Objectives: Iron deficiency anemia (IDA) is a common hematological disorder and cause of low hemoglobin. Preoperative anemia has been demonstrated to increase the risk of adverse outcomes after posterior cervical fusion and other spinal surgeries. The need for a transfusion during lumbar fusion has been shown to increase length of stay. This study aimed to assess the impact of IDA on outcomes after spinal fusion for adult spinal deformity (ASD).

Methods: The New York Statewide Planning and Research Cooperative System (SPARCS) database was searched from 2009 to 2013 to identify all patients undergoing ≥2-level thoracolumbar spinal fusion (primary and revision) for ASD with a 2-year follow-up. The patients were then stratified by the presence or absence of IDA. Patients with IDA and patients without IDA were subjected to 1:1 propensity score matching based on age, sex, and obesity. Univariate analysis was employed to compare demographics, hospital parameters, and rates of adverse outcomes. Multivariate binary logistic regression with odds ratio (OR) was employed to identify independent risk factors for adverse postoperative outcomes.

Results: A total of 524 patients (262 with IDA and 262 without IDA) were identified. Patients with IDA experienced higher rates of overall surgical complications (50.4% vs 23.7%, P < 0.001), wound complications (3.4% vs 0.4%, P = 0.011), and blood transfusion (10.3% vs 6.5%, P < 0.001). No difference was observed in the rate of overall medical complications. Patients with and without IDA had comparable rates of readmission (8.0% vs 13.0%, P = 0.064), although patients with IDA had lower rates of reoperation (7.6% vs 13.0%, P = 0.044). There was no mortality in either cohort. IDA was independently associated with wound complications (OR = 10.6, P = 0.028), blood transfusion (OR = 3.9, P < 0.001), and surgical complications (OR = 3.5, P < 0.001).

Conclusions: Baseline IDA was predictive of increased wound complications, postoperative blood transfusion, and overall surgical complications after thoracolumbar fusion surgery for ASD. Our findings could inform potential medical interventions to mitigate the risks of adverse outcomes in patients with IDA.

Introduction: During spinal surgery, management of intraoperative bleeding and effective hemostasis are required to clearly visualize the surgical field and to safely perform procedures and positive postoperative outcomes. However, it is challenging to stop bleeding from the venous plexus around the dural sac due to the potential risk of neural tissue damage. We aimed to develop hemostatic sheets with appropriate characteristics for spinal surgery, such as softness, appropriate thickness, biodegradability, thrombin bioactivity, and minimal water-induced expansion.

Methods: Hemostatic sheets were made by dissolving bovine bone-derived gelatin in water and aerating it to form foam, followed by freeze-drying, crosslinking, and thrombin-soaking. Sheets A to H were produced with different gelatin concentrations, foam densities, and crosslinking times by additional heat treatment. The sheets were then soaked in thrombin solution for enhanced hemostasis. Material properties, such as density, tensile strength, biodegradability, and hemostatic capacity, were evaluated. Sheet efficacy was further assessed with liver bleeding and spinal venous plexus bleeding models in a miniature pig.

Results: High-density gelatin sheets showed stable shape retention in wet conditions and robust tensile strength. Sheets with higher density and more crosslinking had prolonged persistence in the pepsin test and lower biodegradability in vivo. Sheet B, produced from a 4% gelatin solution with heating at 155°C for 4 h, showed the best balance of properties, such as no deformation cracks, rapid water absorption, minimal expansion, and faster degradation within 10 weeks, compared with TachoSil and other sheets. In hemostasis models, Sheet B outperformed Avitene and TachoSil, achieving higher success rates in spinal (four out of six sites) and liver bleeding (five out of five sites) models.

Conclusion: A thrombin-loaded hemostatic sheet produced from 4% gelatin solution with a short heating time for crosslinking demonstrated well-balanced material properties, such as shape retention, biodegradability, and wet expansion rate, which resulted in effective hemostasis in in vivo models. These advances may contribute to surgical hemostatic applications.

Introduction:

This study aimed to compare the biomechanical stress at the proximal junctional aspect between the conventional pedicle screw (PS) fixation (PSF) and the low PS density fixation (LPF) method.

Methods:

This study involved 10 patients, half of whom have non-osteoporosis and the other half have osteoporosis. We made two types of intact models (one is from the upper thoracic-to-pelvis model, and the other is from the lower thoracic-to-pelvis model). From the intact models, we constructed two kinds of fusion models: (1) PSF and (2) LPF. The LPF method was as follows: The claw hooks (the combination of the down-going transverse process hooks and facet hooks) were set at the upper instrumented vertebra (UIV) and sublaminar wires at the thoracic spine and PSs at the lumbo-pelvis.

Results:

Upper thoracic to pelvis fixation model

In non-osteoporosis, no significant difference between the PSF and LPF is found. In osteoporosis, the von Mises stresses of the vertebra body at UIV, UIV + 1, and disc were significantly lower in LPF than in PSF.

Lower thoracic-to-pelvis fixation model

In non-osteoporosis, the average von Mises stress of the vertebral body at UIV + 1 and the maximum stress at UIV were lower in LPF than in PSF; however, no significant difference was found in the others. In osteoporosis, the von Mises stress was significantly lower in LPF than in PSF.

Conclusions:

The claw hooks stabilized the vertebra body at UIV firmly, and sublaminar wires reduced load translation from the fixed spine.

Introduction: Pre- and postoperative optimization remains a complex process impacted by various demographic factors. Our study aims to identify and describe those demographic factors associated with poor outcomes after spinal fusion with instrumentation in neuromuscular scoliosis to reduce health disparities and improve postoperative outcomes.

Methods: A retrospective analysis was conducted using Healthcare Cost and Utilization Project data from 2016 to 2020, encompassing a random sample of 20% of procedures in the United States. Data included demographic and hospital variables, including days from admission to the procedure, length of stay, recovery time, total charge, discharge disposition, and mortality rates. In addition to ANOVA, Chi-Squares, and t-tests, multiple-linear and multiple-logistic regression models were designed and run to generate adjusted odds ratios.

Results: Compared to non-Hispanic patients (N = 1829), Hispanic patients (N = 431) had spinal fusion with instrumentation at younger ages (12.9 vs. 14.1 years old, p = 0.011) and had significantly different household incomes with less representation in the 75th to 100th percentile (16.8% vs. 26.5%, p < 0.001). Additionally, Hispanic patients were more likely to be Medicaid users (67.2% vs. 46.0%, p < 0.001). Hispanic patients undergoing spinal fusion with instrumentation had longer lengths of stay (LOS) (10.0 vs. 7.6 days, p < 0.001), longer periods from admission to surgery (wait time) (1.6 vs. 1.0 days, p = 0.046), and longer recovery times (8.5 vs. 6.7 days, p < 0.001).

Conclusions: Hispanic patients with NMS often have longer lengths of stay, longer periods between admission and surgery, and longer recovery times than non-Hispanic patients. This difference in hospital courses and surgical timing could be an effect of disparities in healthcare access and socioeconomic standing. Further efforts are required to both understand and reduce barriers to healthcare access in the Hispanic patient population undergoing spinal fusion with instrumentation.

Introduction: Due to global increases in life expectancy, numbers of both super-elderly patients (≥90 years old) and the spine surgeries they undergo are increasing. However, no studies on spine surgery for super-elderly patients have focused on patient-reported outcomes (PROs).

Methods: Subjects were elderly patients (over 75 years old) undergoing spine surgery for degenerative disease (4408 cases) performed at our 13 affiliated centers between April 2017 and August 2021. Surgical procedures, perioperative complications, and PROs were investigated and compared between patients ≥90 years old (SE group) and control patients 75–89 years old (E group).

Results: Although the two groups showed no significant differences in patient background, the SE group showed significantly fewer fusions. The incidence of perioperative complications, including death within 30 days, did not significantly differ between groups. Regarding PROs, there were no significant differences in percentages of patients who achieved minimum clinically important differences in Neck Disability Index, Oswestry Disability Index, or EuroQoL 5 Dimension. There were no significant differences in pre- and postoperative numeric rating scales for each item or patient satisfaction.

Conclusions: There were significant improvements in PROs at 1 year postoperatively in the SE group than in the E group, and there were no significant differences in perioperative complication rates or mortality.

Lumbar spine microscopic decompression (LSMD) is a common surgical procedure for decompressing neural elements. Although the optimal extent of decompression remains a critical consideration, limited evidence-based guidelines define the threshold for instrumented fusion to maintain biomechanical stability. Existing studies suggest that unilateral LSMD generally does not result in iatrogenic instability. However, the potential instability associated with bilateral segmental decompression (BLSMD) is less well-defined, particularly in patients with pre-existing degenerative lumbar scoliosis (SC) or spondylolisthesis (SL).

This retrospective study included patients undergoing BLSMD without instrumented fusion. Pre-existing SC was defined as Cobb' s angle ≥10° and SL as any anterior–posterior slip of operated level adjacent vertebral bodies. The primary outcome was new or progressive SC/SL measured on pre and postoperative radiographs. Secondary outcomes were revision rates, changes in Visual Analog Scores (bVAS/lVAS), and Oswestry Disability Index (ODI) scores, collected preoperatively and 1–2 years postoperatively. Baseline characteristics such as age, BMI, sex, and number of levels operated were also collected.

A total of 31 patients were reviewed comprising 15 female and 16 male patients with a mean age of 61.4 years (21–78) and BMI of 26.5 (18–41). There were 14 one-level, 12 two-level, and 4 three-level BLSMD performed. Patients with pre-existing SC and SL had a 66% and 23% incidence of radiological progression, respectively, compared to 0% in patients without pre-existing deformity. Progression cases were associated with high reoperation rates (up to 75%) and seemed to have inferior clinical outcomes than those without progression.

In patients undergoing BLSMD, pre-existing SC/SL is linked to a higher incidence of radiological progression and higher reoperation rates. For patients with SC/SL, careful consideration should be given to limiting decompression, potentially exploring fusion options, and implementing close postoperative radiographic monitoring.

Introduction: Whether the benefits of continued perioperative aspirin therapy in spinal surgery outweigh the risk of perioperative complications remains unclear. This study evaluates the perioperative effects of continuous low-dose aspirin treatment in patients who underwent lumbar decompression alone.

Methods: This single-institute retrospective study included patients who underwent lumbar decompression for L1/2–L5/S1 lesions. The patient characteristics, perioperative parameters, and complications were compared between 103 patients who continued to take 100 mg/day aspirin during the perioperative period (aspirin group) and 653 patients who did not take antiplatelet or anticoagulant drugs (nonaspirin group).

Results: A significantly higher proportion of the patients in the aspirin group were males. The patients in the aspirin group had significantly lower preoperative hemoglobin levels than those in the non-aspirin group (P = 0.001 and P = 0.044, respectively). No significant differences were detected between the groups in terms of the number of disc decompression levels, duration of surgery, intraoperative blood loss, postoperative drainage volume, number of reoperations required for epidural hematoma formation, or perioperative blood transfusions. No cardiovascular or cerebrovascular ischemic events occurred in either group.

Conclusions: Continuous low-dose aspirin therapy alone during the perioperative period for lumbar decompression did not increase perioperative bleeding or the risk of bleeding-related complications. In conclusion, continuous low-dose aspirin treatment may be acceptable for use in preventing the increased risk of cardiovascular disease caused by aspirin withdrawal in patients undergoing lumbar decompression.

Introduction: This study investigated the mid- to long-term postoperative outcomes of patients with adult spinal deformity (ASD), focusing on physical function and quality of life (QOL). We also compared age-related changes between patients aged 75 years or older (high elderly) and those younger than 75 years (low elderly).

Methods: A total of 47 patients with ASD underwent thoracic-iliac long spinal fusion between August 2013 and September 2014. The study spanned from the preoperative period to at least 5 years postoperatively. Physical function was assessed using isometric hip flexion and knee extension muscle strength, the 6-min walk distance test, the 10-m walk test, and the timed up and go test. QOL was assessed using the Scoliosis Research Society-22 and Oswestry Disability Index. Repeated-measures analysis of variance with a mixed model approach, corrected for multiple comparisons using Bonferroni, was performed.

Results: Of the 47 patients, 21 participated in the study. Patients with ASD showed improved gait ability postoperatively. Hip flexor strength decreased at more than 5 years postoperatively compared with the preoperative strength. Patient-reported outcome (PRO) scores showed continuous improvement postoperatively, regardless of age. Although older patients had lower preoperative and postoperative physical function, their PRO scores significantly improved and remained favorable for more than 5 years postoperatively.

Conclusions: Patients with ASD experienced sustained improvements in walking ability and PRO for more than 5 years postoperatively. The results of this study showed that even among the elderly, PRO scores consistently improved after surgery and remained positive for an extended period.

Introduction: There is a lack of research on the relationship between cervical spinal cord injury (SCI) surgery and symptomatic urinary tract infections (UTIs); hence, this study seeks to fill this critical knowledge gap in postoperative care. This study aims to identify the risk factors for UTIs in patients with traumatic cervical SCI.

Methods: We retrospectively analyzed 187 patients (mean age: 68 years) who underwent cervical SCI surgery between 2017 and 2021. Patients were categorized into UTI and non-UTI groups. Patients with recurrent UTIs were defined as the multiple-UTI group. Preoperative risk factors, including prognostic nutritional index (PNI; 10 × serum albumin [g/dL] + 0.005 × total lymphocyte count [/μL]), were assessed.

Results: Among 187 patients, 99 (52.9%) experienced a UTI within 90 days postoperatively. The majority of patients in the UTI group, that is, 92 patients (92.9%), had an indwelling catheter as urinary management at the time of the UTI. The UTI group faced higher rates of cardiopulmonary dysfunction, bacteremia, longer hospital stays, and increased medical costs. Multiple UTIs were associated with worse outcomes, including increased complications, longer hospital stays, and higher medical costs. PNI at 3 weeks and 4 weeks postoperatively in the multiple-UTI group was significantly lower than in the single-UTI and non-UTI groups. The American Spinal Injury Association impairment scale grade at admission was independently linked to initial UTI occurrence within 90 days after surgery when adjusting for confounding variables.

Conclusions: We found that 52.9% of patients experienced UTIs within 90 days postoperatively. The risk factors for UTI occurrence included the severity of paralysis, indwelling catheter, and poor improvement in the perioperative nutritional status. Early interventions with intermittent catheterization, appropriate antibiotics, and nutrition might be suggested for patients with severe cervical SCI and malnutrition.

Objectives

Gait changes could occur after thoracic to pelvic long-segment corrective fusion surgery, a common procedure for adult spinal deformity (ASD), potentially affecting the occurrence and progression of postoperative hip osteoarthritis. We aimed to clarify postoperative pelvic kinematics in patients with ASD by performing gait analysis using a system based on a smartphone-integrated inertial measurement unit (IMU).

Methods

A total of 21 consecutive outpatients (73.6 ± 4.6 years old, 2 men, 19 women) were enrolled. All had undergone long-segment fusion from the thoracic spine to the pelvis for ASD more than 1 year previously and could walk unassisted. A control group comprised 20 healthy volunteers. The IMU was fixed on the sacrum, and data were collected when subjects walked forward on a flat indoor floor. Acceleration in three axial directions and angular velocity around the three axes were recorded simultaneously during gait, and data were cut out for each gait cycle. Of 1043 features obtained, the top 20 features with the smallest p-value in a statistical comparison were selected. These features, plus gender and age, were classified using gradient boosting machine learning based on the decision tree algorithm. The classification accuracy and relative importance of the feature items were calculated.

Results

The accuracy rate for gait classification between groups was 96.7% and the F1-score was 0.968. The factor that contributed most to the classification of gait in both groups was "y-angular,_change_quantiles,_f_agg="var",_isabs=True,_qh=0.6,_ql=0.2," which means the variance of the change of the absolute value in the pelvic rotation angular velocity in the horizontal plane in the range of 20%–60% of the gait cycle. Its relative importance was 0.351, which was smaller in the group with fusion.

Conclusions

Patients with ASD following long-segment fusion from the thoracic spine to the pelvis apparently have a gait style characterized by suppressed pelvic rotation in the horizontal plane.

Background: Intervertebral disc degeneration (IDD) is a primary cause of chronic back pain and disability, highlighting the need for precise detection and grading for effective treatment. This study focuses on developing and validating a convolutional neural network (CNN) with a You Only Look Once (YOLO) architecture model using the Pfirrmann grading system to classify and grade lumbar intervertebral disc degeneration based on magnetic resonance imaging (MRI) scans.

Methods: We developed a deep learning model trained on a dataset of anonymized MRI studies of patients with symptomatic back pain. MRI images were segmented and annotated by radiologists according to the Pfirrmann grading for the datasets. The segmentation MRI-disc image dataset was prepared for three groups: a training set (1,000), a testing set (500), and an external validation set (500) to assess model generalizability without overlapping images. The model's performance was evaluated using accuracy, sensitivity, specificity, F1 score, prediction error, and ROC-AUC.

Results: The AI model showed high performance across all metrics. For Grade I IDD, the model achieved an accuracy of 97%, 95%, and 92% in the training, testing, and external validation sets, respectively. For Grade II, the sensitivity was 100% in both training and testing sets and 98% in the validation set. For Grade III, the specificity was 95.4% in the training set and 94% in both testing and validation sets. For Grade IV, the F1 score was 97.77% in the training set and 95% in both testing and validation sets. For Grade V, the prediction error was 2.3%, 2%, and 2.5% in the training, testing, and validation sets, respectively. The overall ROC-AUC was 97%, 92%, and 95% in the training, testing, and validation sets, respectively.

Conclusions: The AI-based classification model exhibits high accuracy, sensitivity, and specificity in detecting and grading lumbar IDD using the Pfirrmann grading. AI has significantly enhanced diagnostic precision and reliability, providing a powerful tool for clinicians in managing IDD. The potential impact is substantial, although further clinical validation is necessary before integrating this model into routine practice.

Introduction: Meningiomas and schwannomas are common intradural–extramedullary spinal tumors. Because of their different origins, they necessitate different surgical procedures, which makes preoperative diagnosis important.

Methods: In this study, clinical and imaging data for 62 patients diagnosed with either meningioma or schwannoma across multiple institutions were analyzed.

Results: The average age of patients was older (67.6 vs. 58.9 years), and the frequency of females was higher (72% vs. 46%) for meningioma than for schwannoma. Meningiomas were mostly found in the thoracic region (84%), whereas schwannomas were commonly located in the lumbar region (54%). For each tumor type, specific radiological findings were identified. For meningiomas, findings included the ginkgo leaf sign (GLS) (sensitivity 58%, specificity 100%), oval shape (sensitivity 84%, specificity 63%), dural tail sign (DTS) (sensitivity 75%, specificity 100%), and intertumoral calcification (sensitivity 39%, specificity 100%). Combining GLS and DTS greatly improved sensitivity to 89% (specificity 100%). For schwannomas, specific findings included a lobule shape (sensitivity 25%, specificity 95%), dumbbell shape (sensitivity 54%, specificity 100%), and cystic changes (sensitivity 54%, specificity 97%).

Conclusions: GLS may be a specific radiological feature for meningiomas and can aid in diagnosis when combined with DTS. Understanding these distinct radiological characteristics is valuable for preoperative differential diagnosis of intradural–extramedullary spinal tumors.

Purpose

There is limited evidence between lumbar disk degeneration and normal lumbar segmental range of motions (SRMs), because previous studies were skewed by age and lacked large cohort of asymptomatic data.We aimed to characterize the normal lumbar SRMs according to age and gender and determine its association with disk degeneration.

Methods

A total of 639 healthy Japanese volunteers (≥50 individuals of each decade of age from 20 to 79) without any symptom or morphological spinal abnormalities, who underwent lumbar radiograph and magnetic resonance image (MRI), were selected retrospectively. SRMs were evaluated by the flexion-extension radiographs taken in the recumbent position. Disk degenerations were assessed according to the Pfirrmann grade using MRI T2 imaging.

Results

The mean SRMs became larger in the lower lumbar level. The range of the mean SRMs was smallest at L1–2 and largest at L4–5: 6 to 9 degrees at L1/2, to peaking at 11–14 degrees at L4/5 in male, and 6–8 degrees at L1/2, to peaking at 11–17 degrees at L4/5 in female. Lumbar disk degeneration progressed faster with age in the lower lumbar spine than in the upper lumbar level. SRM did not change depending on the severity of disk degeneration in upper lumbar spine, but significantly decreased with progressive disk degeneration in the lower lumbar spine.

Conclusions

These findings could help to identify the normal lumbar SRMs that might be useful to evaluate the instability or inflexibility in the clinical situation. Furthermore, our results demonstrated the transition of the normative lumbar SRMs based on age, gender, and lumbar level.

Introduction: The risk factors for the development of progressive segment degeneration (PSD) after decompression surgery are still unknown. In this study, the risk factors for PSD in patients who undergo decompression surgery for lumbar spinal stenosis with and without coexisting spondylolisthesis and scoliosis were examined, focusing on decompression and non-decompression segments.

Methods: We reviewed the data of patients with >5 years of postoperative follow up. Radiographic PSD was defined as either the development of an anterolisthesis or retrolisthesis of >3 mm or a decrease in disc height of >3 mm during the 5-year follow up. On the basis of intervertebral segments, the association between PSD and other preoperative clinical findings was analyzed.

Results: Overall, 840 lumbar segments (L1–L2 to L5–S1) in 168 patients, with a mean age of 69.5 ± 9.2 years, met the inclusion criteria. PSD was observed in 162 (19.3%) lumbar segments. A logistic regression model identified that Cobb angle ≥10° (OR 2.53, 95% CI 1.50–4.24), spondylolisthesis ≥3 mm (OR 4.447, 95% CI 2.06–9.58), and level of segments were more likely to have PSD at the non-decompression level; additionally, lateral listhesis ≥3 mm (OR 2.91, 95% CI 1.08–7.81) was more likely to have PSD in the decompression segments. In clinical outcomes in patients with PSD at baseline and the 5-year follow-up, no significant difference was found.

Conclusions: Even though PSD does not correlate with worsening symptoms, our study confirms that a higher degree of pre-existing disc degeneration is indicative of a higher PSD in 5 years.

Introduction

Sacral perineural cysts are rarely symptomatic; however, they may occasionally cause various symptoms. As the patient exhibits multiple cysts, it often becomes difficult to determine if these cysts are symptomatic.

Technical Note

Six patients with multiple sacral cysts, identified using magnetic resonance imaging (MRI), were further examined using myelography and computed tomography (CT) immediately and 6–18 h after myelography. Symptomatic cysts were exclusively diagnosed as not enhanced immediately (filling defect sign) but displayed enhancement later (delayed filling sign/retention sign) compared to the subarachnoid space. A minimal laminectomy was performed on the target cyst. The dura and epineurium with the arachnoid of the cyst were then longitudinally incised along the nerve root, and the adhesion at the junction between the cyst and the dura mater was released. The incised epineurium and dura mater were sutured using 6-0 nylon and covered with multiple layers of polyglycolic acid seat and fibrin glue. A suction drain was placed for 1 or 2 days, and the patients were mobilized on postoperative day 1. Symptoms improved in all patients; however, the improvement ratio varied. At an average follow-up of 39 months, no recurrence was observed on the MRI.

Conclusion

This case series reports the diagnostic and surgical methods for multiple sacral perineural cysts and their outcomes. Delayed CT myelography is helpful in diagnosing symptomatic cysts. Moreover, all cysts with filling defect signs or delayed filling/retention signs demonstrated neural adhesions in the neck. Microsurgical fenestration and the release of adhesions are effective for the improvement of symptoms without recurrence.

Introduction: Fifth lumbar (L5) vertebral morphology contributes to spondylolysis. However, there are no comprehensive examinations of the three-dimensional vertebral shape in early-stage cases. This study aimed to investigate the overall L5 vertebral shape in early-stage spondylolysis.

Methods: Homologous models of the L5 vertebra were constructed using computed tomography data from 72 patients with early-stage spondylolysis (SP group) and 95 patients without spondylolysis (CON group). Principal component analysis was performed on the three-dimensional coordinates of all vertices of the generated homologous models. The groups' principal component scores were compared.

Results: Principal component (PC) 3, which represents the morphology of the cross-sectional area of the vertebral body; length of pedicle, neural arch, and isthmus; shape of the vertebral body; and spinous process orientation were significantly higher in the SP group than in the CON group. Additionally, the SP group showed higher values for PC10, which represents the morphology of the anteroposterior length of the vertebral body and transverse process orientation. Compared to the CON group, the SP group' s PC3 had a smaller cross-sectional vertebral body area, longer pedicle and neural arch length, larger dorsal wedge shape of the vertebral body, horizontally oriented spinous process, and a shorter isthmus length. PC10, compared with the CON group, indicated the SP group had a shorter anteroposterior length of the superior and inferior surfaces of the vertebral body and a coronally oriented transverse process.

Conclusions: The overall L5 vertebral shape differed between individuals with and without early-stage spondylolysis. Our findings suggest that a wedge-shaped vertebral body and shorter isthmus length may be associated with spondylolysis development. Our study may be valuable in elucidating spondylolysis pathogenesis and may contribute to early detection and prevention.

Introduction

Minimally invasive surgical treatment of myelopathy caused by central thoracic disc herniation (TDH) is challenging to carry out because reaching the herniation site is difficult and the thoracic spinal cord is fragile. In this study, using the posterior–lateral approach for central TDH with myelopathy, we present a novel procedure of transcostal microendoscopic discectomy (TCMED).

Technical Note

The patient was operated in a prone position under general anesthesia. At a preoperatively determined distance from the midline, an 18-mm-long longitudinal incision was conducted, and using a 25-degree microendoscope, the operation was carried out. The endoscope was placed at an inward angle of approximately 50 degrees in the vertical direction. The ribs adjacent to the disc were identified, and the disc was exposed by resecting the ribs using a surgical high-speed drill while preserving the cortical bone of the ribs on the pleural side. The herniation was identified by drilling the ventral side of the disc and was then successfully removed. After discectomy, the dura mater expanded ventrally.

Three male patients (mean age, 47.3 years) were treated, with 20 weeks of follow-up on average, 237.7-min mean operative time, and 26.7-mL mean blood loss. The average preoperative modified Japanese Orthopedic Association score was 5.2/11, which improved to 9.5/11 postoperatively, with a 75.6% average recovery rate. The 10-s step test score improved from an average of eight times preoperatively to 20 times postoperatively. No serious perioperative or postoperative complications or residual rib pain were observed.

Conclusions

The proposed TCMED approach for treating central TDH that causes myelopathy allows for safe access to the level of the posterior vertebral wall using the rib as a landmark for resecting the rib head without opening the chest. Using the angled microendoscope and curved surgical instruments, the central TDH, located ventral to the spinal canal, can then be safely and effectively resected without spinal cord retraction.

Introduction: Patients with adult spinal deformity (ASD) lean forward with their trunks when walking, even if they can remain upright during static standing. However, it remains unclear which part of the spinal column is involved in forward trunk tilt and the details of the relationships between sagittal alignment during static standing and changes in dynamic parameters during walking. Therefore, this study aimed to clarify the above by analyzing the walking motion of ASD patients using inertial measurement units (IMUs).

Methods: Preoperative ASD patients were included in this study. Dynamic parameters during gait were measured by IMUs attached on the skin at the T1, T12, and S1 spinous processes, thigh, and lower leg. Walking data were divided into three phases of 10 s each (initial, middle, and final), and the average dynamic parameters at each phase were statistically compared. The relationships between the standing radiographic and dynamic parameters in the final phase were evaluated by linear regression analyses.

Results: A total of 34 patients were included in this study. Their mean age was 72 years. The inclination of IMUs on the T1, T12, and S1 and the flexion angle of T12-S1 IMUs significantly increased over time. Pelvic tilt (PT) of standing radiography was positively correlated with the inclination angles of T12 (r² = 0.22, p = 0.0048) and S1 (r² = 0.16, p = 0.0178) and the flexion angle of T12-S1 IMUs (r² = 0.29, p = 0.0011).

Conclusions: This study showed that anteversion of the trunk in patients with ASD is due to an increase in lumbar forward bending and anterior tilt of the pelvis. Lumbar forward bending was significantly correlated with PT on standing radiography. It is important to consider the presence of poorer posture during gait than during standing when we evaluate patients with high PT.

Introduction

Adult spinal Langerhans cell histiocytosis (LCH) presents a treatment challenge due to ongoing controversies. Traditional approaches such as curettage with bone grafting and internal fixation are preferred for severe cases involving mechanical instability, neurological deficits, or deformity. This study aimed to explore the efficacy of a customized approach involving simple posterior instrumentation without curettage or bone grafting in treating adult spinal LCH.

Methods

This retrospective study analyzed a prospectively maintained database of all spine surgeries conducted at our institute from April 2013 to December 2020. Adult patients (age ≥ 20) diagnosed with LCH were included. We assessed surgical methods, adjuvant therapy, and clinical results, such as perioperative progression of disease, symptoms, and recurrence.

Results

Four male patients aged between 21 and 28, each with a single spinal LCH lesion (T6, T5, and C5) except one case (T5 and T7), were treated. Diagnoses were confirmed via biopsy (two open, two needle biopsies). Whole-body computed tomography or bone scintigraphy revealed no additional LCH lesions in any patient, except in one patient with a small lung nodule. All patients presented with severe back or neck pain and pathological fractures at the affected vertebra. Thoracic LCH cases received percutaneous pedicle screw fixation, while the cervical case was managed with conventional posterior instrumentation using lateral mass screws. After surgery, all patients experienced significant pain relief, halted bone lysis, and rapid new bone formation. One patient underwent chemotherapy postsurgery. Over 3 years of follow-up, imaging studies revealed no recurrences of the disease.

Conclusions

Posterior instrumentation, without the need for curettage or bone grafting, is a promising surgical treatment for adult spinal LCH. This method may effectively halt lesion progression, prevent spinal deformity, and avert neurological deficits in the patients with progressive spine lesion where conservative treatment may not adequately prevent vertebral fractures.

Introduction: In high-grade spinal osteotomy involving large anterior column resection, restoration of the structural integrity of the posterior column at the osteotomy site can reduce postoperative instrumentation failure (IF). This study aimed to describe our technique of posterior strut bone grafting using an en bloc resected vertebral arch, which is useful for posterior column reconstruction after high-grade osteotomies during surgeries for spinal tumor and deformity in the lower lumbar spine.

Technical Note: Using a posterior approach, en bloc resection of the targeted vertebral arch was performed in accordance with the surgical technique for total en bloc spondylectomy (TES). The posterior elements in the upper and lower adjacent vertebrae were separated by a significant space after vertebral body resection followed by cage insertion in TES or anterior column osteotomy followed by correction in deformity surgery. To create a new posterior column, the en bloc resected vertebral arch was placed at 90 ( rotation to bridge the upper and lower vertebral arches. Using this technique, an abundant amount of bone chips made from the resected vertebral elements were placed over the en bloc resected posterior arch as an additional bone graft. The technique was used in three patients who underwent TES for spinal tumors and in one patient who underwent grade 4 osteotomy for adult spinal deformity in the lower lumbar spine. One year after surgery, computed tomography showed that the structural integrity of bony fusion was successfully achieved between the en bloc resected arch and the posterior elements of the adjacent vertebrae in all patients and showed no postoperative IFs.

Conclusions: This bone graft technique created new continuity of the posterior column after high-grade osteotomies in the lower lumbar spine. Bone fusion was achieved in the posterior elements to prevent IF after surgery.

Introduction

This study aimed to identify factors associated with intervertebral disc degeneration (DD) in adolescent idiopathic scoliosis (AIS) patients who reached middle and older age after surgery.

Methods

A total of 252 AIS patients who underwent spinal fusion surgery between 1968 and 1988 were included in this survey-based study. Patients with a mean follow-up period of 40.9 years were evaluated through lumbar spine Magnetic resonance imaging (MRI), radiographic assessments, and patient-reported outcome measures (PROMs). DD was evaluated using the Pfirrmann grading system. Various factors, such as surgical levels, sagittal alignment, and PROMs, were analyzed for their association with DD.

Results

Among the 21 participants who underwent both previous (conducted from 2014 to 2016) and latest surveys (conducted in 2022), the prevalence of DD increased from 66.7% in the previous survey to 76.9% in the latest survey. The overall Pfirrmann disc score significantly increased from 3.2 to 3.5. Sagittal alignment parameters, such as sagittal vertical axis (SVA), pelvic incidence minus lumbar lordosis (PI-LL), and pelvic tilt (PT), worsened over time. Scores in the Scoliosis Research Society-22 Questionnaire pain, Roland-Morris Disability Questionnaire, and Oswestry Disability Index were significantly worse in the latest survey than in the previous one. Comparison between patients with the lower instrumented vertebra (LIV) at L4 or lower and L3 or higher revealed significantly higher disc scores and 100% prevalence of DD in the L4 or lower group. Factors associated with DD included LIV at L4 or lower, smaller LL, larger thoracolumbar kyphosis, and increased SVA, PI-LL, and PT.

Conclusions

This study suggests that maintaining the LIV at L3 or higher, achieving good sagittal alignment, and maintaining LL may help prevent long-term DD in AIS patients.

Introduction

Previous studies have shown that early patient mobility and activity can improve patient outcomes after lumbar fusion procedures. This study aimed to explore the relationship between patient mobility and activity, measured by the Activity Measure for Post-acute Care (AM-PAC) "6-Clicks" assessment and postoperative outcomes in lumbar fusion patients.

Methods

A retrospective review of 306 lumbar fusions (105 with 6-Clicks mobility and 289 with 6-Clicks activity scores) was conducted. Statistical analyses were performed to evaluate the relationship between 6-Clicks scores and postoperative outcomes, such as prolonged length of stay (LOS), nonhome discharge, 30-day emergency department (ED) returns and readmissions, and minimal clinically important difference (MCID) achievement on the PROMIS-PF instrument at 3–12 months postoperatively.

Results

After controlling for age, body mass index, sex, race, number of levels, and preoperative PROMIS-PF, higher 6-Clicks mobility scores decreased the likelihood of 3+ day LOS (OR: 0.72; p = 0.010), non-home discharge (OR: 0.68; p < 0.001), and 30-day ED return (OR: 0.78; p = 0.022) and increased the likelihood of PROMIS MCID achievement (OR: 1.28; p = 0.004). The odds of LOS 3+ days, non-home discharge, and ED return for each one-point increase in mobility scores all decreased by 28%, 32%, and 22%, respectively, while the odds of achieving PROMIS MCID for every one-point increase in mobility increased by 28%. After risk adjustment, higher 6- Clicks activity scores were protective against 3+ day LOS (OR: 0.78; p < 0.001) and non-home discharge (OR: 0.69; p < 0.001).

Conclusions

The AM-PAC 6-Clicks mobility and activity scores hold value as early indicators of prolonged LOS and nonhome discharge, while mobility scores may help identify patients who are at risk for ED returns and who fail to experience clinically significant improvement in physical function. These tools may be used to identify patients requiring additional resources and can inform discussions surrounding patient expectations.

Objectives

After posterior lumbar interbody fusion (PLIF), trabecular bone remodeling (TBR) occurs in the vertebral body. This study aimed to investigate whether imaging findings obtained with PLIF are applicable to lateral lumbar interbody fusion (LLIF).

Methods

A total of 53 cases who underwent one- or two-level LLIF with polyether ether ketone cage and posterior spinal fixation/fusion (PSF) were retrospectively included in this study. TBR, vertebral endplate cyst (VEC), facet union, and pseudarthrosis were investigated on computed tomography (CT) images at 3 months, 1 year, and 2 years postoperatively. Of the 53 patients, 36 (68%) who underwent CT examination at approximately 5 years postoperatively were subanalyzed.

Results

TBR was commonly observed anterior to the cage on CT sagittal images. The TBR-positive rate was 21%, 67%, and 73% at 3 months, 1 year, and 2 years postoperatively, respectively. The 3-month TBR-positive segments showed significantly less VEC (0% vs. 29%, P = 0.029) at 1 year postoperatively. The 1-year TBR-positive segments showed a significantly higher facet union rate (83% vs. 57%, P = 0.019) and less pseudoarthrosis (0% vs. 13%, P = 0.041) at 2 years postoperatively. At 5 years postoperatively, 50% of the 2-year TBR-positive segments turned negative with solid intervertebral bony fusion.

Conclusions

TBR-positive segments had significantly lower future VEC positivity, higher future facet union rates, and lower future pseudarthrosis rates. In LLIF-PSF, TBR suggests the establishment of intervertebral stability and allows consideration of intervertebral biomechanics.

Background: Preoperative estimations of blood loss are important when planning surgery for cervical spine injuries in older adults. The association between ankylosis and blood loss in perioperative management is of particular interest. This multicenter database review aimed to evaluate the impact of ankylosis on surgical blood loss volume in elderly patients with cervical spine injury.

Methods: The case histories of 1512 patients with cervical spine injury at among 33 institutions were reviewed. After the exclusion of patients without surgery or whose blood loss or ankylosis status was unclear, 793 participants were available for analysis. Differences in blood loss volume were compared between the Ankylosis (+) group with ankylosis at the cervical level and the Ankylosis (−) group without by the inverse probability of treatment weighting (IPTW) method using a propensity score.

Results: Of the 779 patients (mean age: 75.0 ± 6.3 years) eligible for IPTW calculation, 257 (32.4%) had ankylosis at the cervical level. The mean blood loss volume was higher in Ankylosis (+) patients than in Ankylosis (−) patients (P < 0.001). This difference did not reach statistical significance when weighted by background factors, with mean blood loss of 244 mL and 188 mL, respectively, after adjustment.

Conclusions: This study revealed that ankylosis was significantly associated with increased blood loss volume when unadjusted by surgical time. Elderly patients with cervical spine injury accompanied by ankylosis appear predisposed to higher bleeding and severe hemorrhage, both as a result of the condition and their particular demographic characteristics.

Objective

This study aimed to investigate the clinical and radiological outcome of "indirect decompression" using lateral–posterior combined surgery for osteoporotic vertebral fracture (OVF) with neurological symptoms.

Methods

A total of 17 patients who underwent lateral and posterior combined indirect decompressive spinal reconstruction (LP-IDR) for single-level OVF with neurological symptoms were included in this study. The neurological symptoms (sensory disturbance and muscle weakness) and imaging findings (local angle and height of the fracture segment and bone fragment occupancy in the spinal canal) were investigated preoperatively, postoperatively, and at the 1-year follow-up.

Results

Muscle weakness was observed preoperatively in ten patients. Nine patients had complete recovery of muscle weakness (p < 0.001), whereas one had residual muscle weakness at the 1-year follow-up. The presence of sensory disturbance was observed in 16 patients preoperatively, and it was significantly reduced to 8 patients at the 1-year follow-up (p = 0.003). The bony fragment occupancy rate in the spinal canal was decreased from 44.0% to 40.2% postoperatively (p = 0.04) and to 33.1% at 1 year (p = 0.002). The local angle was corrected from 8.3° to −2.6° postoperatively (p = 0.003) and to 1.2° at 1 year. The local height was corrected from 26.7 to 32.0 mm postoperatively (p < 0.001) and to 29.8 mm at 1 year.

Conclusions

LP-IDR for OVF with neurological symptoms provided sufficient neurological improvement with expansion of the spinal canal over time.

Introduction: This study aimed to standardize perioperative interruption of antiplatelet agents in patients undergoing cervical spinal surgery and investigate the incidence of epidural hematoma and thrombotic complications.

Methods: A total of 153 patients, consisting of 85 men and 68 women, were included in this study. Their mean age was 65.5 years. They were divided into two groups: Groups A and B. Group A (139 patients) did not receive preoperative antiplatelet agents, and Group B (14 patients) resumed antiplatelet agents from 7 or 14 days presurgery to 3 days postsurgery. Our analysis encompassed demographic data before surgery, postoperative magnetic resonance image-based assessment of radiological epidural hematoma (EH), and complications such as symptomatic hematoma, blood transfusion, stroke, and venous thromboembolism after surgery.

Results: The frequency of medical conditions, such as hypertension, diabetes, and hyperlipidemia, was significantly higher in Group B than in Group A. The CHADS2 scores, which serve as a clinical prediction rule for estimating stroke risk, were significantly higher in Group B than in Group A. In contrast, the intraoperative blood loss was significantly lower in Group B than in Group A. There was no significant difference in radiologically severe EH, hemorrhage, and thrombotic complications between the two groups. Interestingly, none of the patients in Group B had hemorrhagic and thrombotic complications.

Conclusions: Our standardized perioperative management of antiplatelet agents did not affect the incidence of radiological EH, hemorrhage, and thrombotic complications in patients undergoing cervical spinal surgery.

Objectives: Disc degeneration is a risk factor of pyogenic spondylitis. However, its degree in patients with pyogenic spondylitis is unknown. This study aimed to determine differences in disc degeneration between patients with pyogenic spondylitis and those with noninfectious lumbar spondylosis.

Methods: A total of 85 patients with lumbar pyogenic spondylitis (the infected group) and 156 with lumbar spondylosis who underwent posterior lumbar interbody fusion (the noninfected group) were retrospectively evaluated. Patients with a previous history of spinal fusion, tuberculous spondylitis, and multilevel infection and those receiving dialysis were excluded. Lumbar spine magnetic resonance imaging of the lumbar spine was conducted. Each disc at the L1/2–5/S levels was graded. The total score of the four discs, excluding the affected disc, was used as the modified disc degenerative disease (DDD) score. Propensity score matching was performed using independent variables such as age, sex, diabetes mellitus, cancer, and steroid use. The modified DDD scores at all and each disc level were compared between the two matched groups.

Results: After matching, 48 patients in the infected group and 88 in the noninfected group were finally included in the study. The mean modified DDD scores of the infected and noninfected groups were 7.63 and 5.40, respectively. The modified DDD scores at all and each disc level were higher in the infected group than in the noninfected group.

Conclusions: The incidence of disc degeneration at all and each disc level was higher in patients with pyogenic spondylitis than in those with noninfectious lumbar spondylosis.

STUDY DESIGN: Prospective case series study

OBJECTIVE: To evaluate curve correctability, complications, and rate of growth following treatment.

BACKGROUND: Distraction-founded techniques such as traditionally growing rods or magnetically controlled growing rods are the almost globally accepted management patterns for early onset scoliosis. However, periodic lengthening operations are still needed. Moreover, an MCGR is difficult to contour, and implant-associated problems are common. We developed concave side apical control of the growing rod in which an additional anchor site is inserted at the apex to enhance stability and assist in the adjustment of axial deformity.

METHODS: Entirely skeletally immature early onset scoliosis (EOS) cases with a progressive curve of >40° and without bone or soft tissue weakness were appropriate for this study. Coronal Cobb angle, sagittal parameters, complications, spinal length, and reoperations were documented with at least a 3-year follow-up.

RESULTS: In this study, 15 patients were involved. The mean age was 7 years. The mean preoperative Cobb angle was 48°, which postoperatively became 12° with the percentage of coronal correction reaching 75.73%. The mean Cobb angle degrees of correction were 39°. T1–S1 height increased by 10 mm/year. Postoperative complications occurred in two cases with single rod technique and rod breakage.

CONCLUSION: The concave side apical control of the growing rod seems to be a hopeful surgical procedure for the management of EOS. Curve correctability in patients was 60% and can be sustained for a minimum of 2 years. Reoperations and complications might not be constricted, but the complication frequency looks more reasonable than in the current systems.

Objectives

For older adults, dysphagia is a serious problem that can occur after spinal cord injury (SCI), but its risk factors are unclear. This study aimed to identify risk factors for dysphagia in elderly patients (≥65 years) with cervical SCI.

Methods

This multicenter study included 707 patients with cervical SCI (mean age 75.3 years). Univariate and multivariate analyses were conducted for patient characteristics and geriatric nutritional risk index (GNRI).

Results

Dysphagia occurred in 69 patients (9.8%). The significant factors were as follows: male sex (odds ratio [OR] 3.43), GNRI <92 (1.83), dementia (2.94), fracture (3.40), complete paralysis (3.61), anterior surgery (3.74), and tracheostomy (17.06). Age was not identified as a risk factor.

Conclusions

Low GNRI before injury was one of the independent risk factors for dysphagia after geriatric cervical SCI. GNRI represents the comprehensive nutritional status of the elderly and reflects feeding function and its recovery capacity.

Background: Full endoscopic spine surgery continues to spread worldwide but has a long learning curve. Conventional endoscopy training uses live pigs or human cadavers, which has disadvantages such as high costs and limited availability. Therefore, this study aimed to develop and evaluate three-dimensional (3D) -printed models for endoscopy training.

Methods: Models for 3D printing were generated using raw imaging data from 1.0-mm slices of computed tomography scans, and each part was printed using a different colored material. The combined model was used for training as part of the full endoscopy training kit.

Results: This approach offers several advantages. First, it enables the creation of accurate disease models, such as lumbar disc herniation and other abnormalities, which are useful for both surgical training and preoperative simulations. Second, it is useful for learning surgical orientation. During surgical training, the surgical field can be viewed directly through an endoscope or with the naked eye. By using various colors, it becomes easier to recognize the orientation. Third, the amount of drilling resection can be easily confirmed, facilitating feedback. Finally, training for various surgical techniques is possible, including endoscopic holding techniques and using the endoscope's outer sheath to retract nerves. However, this approach also has some disadvantages, such as the lack of bleeding, inability to reproduce tissue hardness, and difficulty in faithfully recreating soft tissue, such as connective tissue, blood vessels, and fat. Therefore, it is difficult to reproduce the hardness of the calcified disc or disc herniation with apophyseal ring fracture. Moreover, 3D-printed models are not suitable for surgical training using the interlaminal approach because it is difficult to perform separation between the ligamentum flavum and dural matter or between the dural matter and intervertebral disc.

Conclusions: 3D-printed models are a useful complement to live pigs and human cadavers in surgical training and can reduce the time required to acquire endoscopic skills.

Introduction: Few studies have assessed the minimum clinically important difference (MCID) of each Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ) domain. This study assessed MCIDs of JOABPEQ in patients with lumbar spine disease by generation.

Methods: We evaluated the JOABPEQ score of 805 consecutive patients with lumbar spine disease undergoing posterior surgery preoperatively and 1 year postoperatively. MCIDs of each JOABPEQ domain were determined using anchor- and distribution-based methods according to age. A question based on the concept of a health transition item was used as the anchor for the MCID decision.

Results: Overall, MCIDs of the JOABPEQ were 28.6 and 27.3 points for pain-related disorder and gait disturbance, respectively. The MCID for the lumbar spine dysfunction domain did not reach 0.6 over the area under the curve. Regarding the differences among generations, MCIDs of pain-related disorder and gait disturbance domains differed slightly between the elderly and middle-aged. The psychological disorder domain did not reflect clinically meaningful changes in the elderly. MCIDs of the social life disturbance domain decreased with age.

Conclusions: Focusing on achieving the ideal responsiveness of patient-reported outcomes across generations, MCIDs of the pain-related disorder and gait disturbance domains may be valuable for patients, regardless of age, when adopting the JOABPEQ for patients with lumbar spine disease undergoing surgery. This study only evaluated cases that underwent posterior lumbar surgery. Future research will necessitate conducting surveys concerning the outcomes of various treatments for lumbar spine disease.

Introduction

Percutaneous vertebral augmentation techniques, such as balloon kyphoplasty (BKP) and vertebral body stenting (VBS), are commonly used for surgical intervention in osteoporotic vertebral fractures (OVFs). However, markedly unstable OVF cases require additional fixation procedures, prompting the exploration of combined percutaneous vertebral augmentation and posterior fixation. A novel surgical approach involving percutaneous vertebral augmentation with penetrating endplate screws (PES) and downward PES, complemented by a short fusion of one above one below, was developed. This study aimed to introduce and report the preliminary outcomes of this technique based on a retrospective analysis of 20 consecutive cases in the short and medium term.

Methods

Surgical indications are a vertebral wedge angle difference of 10° or more, vertebral pedicle fractures, posterior wall fractures, and diffuse low-signal changes exceeding 50% on T1-weighted magnetic resonance imaging. The procedure is reserved for highly unstable cases following a comprehensive health assessment. The surgical technique involves prone positioning, fluoroscopy-guided percutaneous vertebral augmentation, and the use of downward PES in the cranial vertebral body and PES for the caudal vertebral body by percutaneous technique. The fixation range is one above and one below.

Results

The case series of 20 patients, with an average follow-up period of 146.9 days, demonstrates a mean surgical time of 57 min and minimal complications. The advantages of the technique are as follows: ease of performance, minimal fixation range, and time efficiency. Risks, such as potential screw loosening and the need for prolonged follow-up, are acknowledged.

Discussion

The technique represents a promising surgical approach that balances the requirements of minimally invasive intervention and relatively robust initial fixation for elderly osteoporotic patients with unstable OVFs. While short- and medium-term results are favorable, long-term observations are needed to further assess its efficacy. This novel technique has a potential to be a valuable surgical option for unstable OVFs.

Introduction: Ligamentum flavum (LF) hypertrophy is the main etiological factor in the development of lumbar spinal stenosis (LSS); however, its molecular pathology remains unclear. Histologically, LF hypertrophy is characterized by a reduction in elastic fibers and an increase in collagen fibers. We previously performed miRNA transcriptomic analysis on excised LF from elderly patients with LSS and identified the insulin receptor signaling along with TGFβ-mediated signaling as pathways involved in ligament hypertrophy. Therefore, this study aimed to investigate the involvement of endogenous insulin as a risk factor for LF hypertrophy in patients with LSS.

Methods: A total of 1,119 patients aged ≥65 years (average: 76.1 ± 5.9 years) treated for LSS including surgery and conservative treatment were analyzed. The flavum canal ratio (FCR) was calculated in the MRI cross-sectional image, and an FCR of 0.4275 or greater was defined as ligamentous stenosis according to Sakai' s criteria. Homeostatic model assessment for insulin resistance (HOMA-IR) was calculated and values ≥2.5 were indicative of insulin resistance in Japanese people.

Results: Fifty-one percent of patients with LSS exhibited LF hypertrophy, correlating with higher age, proportion of males and diabetic patients, BMI, HOMA-IR, and creatinine. Among LSS patients, 43.0% had insulin resistance, with 47.1% exhibiting LF hypertrophy and 38.6% without LF hypertrophy, with a significant difference. (p < 0.01) LSS patients with high insulin resistance also demonstrated significantly higher FCR (p < 0.05) and a higher percentage of LF hypertrophy. (p < 0.01) Conditional logistic regression analysis, adjusting for age, identified HOMA-IR as a significant factor.

Conclusions: The study establishes an association between LF hypertrophy and insulin resistance. Considering LF hypertrophy as an inflammation-triggered degeneration of elastic fibers, age-related changes in LF may underlie the basis of inflammatory aging.

Objective

Elderly patients have a higher frequency of upper cervical fractures caused by minor trauma; nevertheless, the clinical differences between mid- and lower-cervical (C6–C7) injuries are unclear. The aim of this study was to compare the epidemiology of lower- and mid-cervical injuries in the elderly.

Methods

This multicenter, retrospective study included 451 patients aged 65 years or older who had mid- or lower-cervical fractures/dislocations. Patients' demographic and treatment data were examined and compared based on mid- and lower-cervical injuries.

Results

There were 139 patients (31%) with lower-cervical injuries and 312 (69%) with mid-cervical injuries. High-energy trauma (60% vs. 47%, p = 0.025) and dislocation (55% vs. 45%, p = 0.054) were significantly experienced more often by elderly patients with lower-cervical injuries than by patients with mid-cervical injuries. Although the incidence of key muscle weakness at the C5 to T1 levels were all significantly lower in patients with lower-cervical injuries than those with mid-cervical injuries, impairments at C5 occurred in 49% of them, and at C6, in 65%. No significant differences were found in the rates of death, pneumonia, or tracheostomy requirements, and no significant differences existed in ambulation or ASIA impairment scale grade for patients after 6 months of treatment.

Conclusions

Elderly patients with lower-cervical fractures/dislocations were injured by high-energy trauma significantly more often than patients with mid-cervical injuries. Furthermore, half of the patients with lower-cervical injuries had mid-cervical level neurological deficits with a relatively high rate of respiratory complications.

Introduction: Pedicle screws are commonly used in fixation to treat various spinal disorders. However, screw loosening is a prevalent complication, particularly in patients with osteoporosis. Various biomechanical studies have sought to address this issue, but the optimal depth and trajectory to increase the fixation strength of pedicle screws remain controversial. Therefore, a biomechanical study was conducted using finite element models.

Methods: Three-dimensional finite element models of the L3 vertebrae were developed from the preoperative computed tomography images of nine patients with osteoporosis and nine patients without who underwent spine surgery. Unicortical and bicortical pedicle screws were inserted into the center and into the anterior wall of the vertebrae, respectively, in different trajectories in the sagittal plane: straightforward, cephalad, and caudal. Subsequently, three different external loads were applied to each pedicle screw at the entry point: axial pullout, craniocaudal, and lateromedial loads. Nonlinear analysis was conducted to examine the fixation strength of the pedicle screws.

Results: Irrespective of osteoporosis, the bicortical pedicle screws had greater fixation strength than the unicortical pedicle screws in all trajectories and external loads. The fixation strength of the bicortical pedicle screws was not substantially different among the trajectories against any external loads in the nonosteoporotic vertebrae. However, the fixation strength of the bicortical pedicle screws against craniocaudal load in the cephalad trajectory was considerably greater than those in the caudal (P = 0.016) and straightforward (P = 0.023) trajectories in the osteoporotic vertebrae. However, this trend was not observed in pullout and lateromedial loads.

Conclusions: Our results indicate that bicortical pedicle screws should be used, regardless of whether the patient has osteoporosis or not. Furthermore, pedicle screws should be inserted in the cephalad trajectory in patients with osteoporosis.

Background: A halo vest is an immobilization device widely used to stabilize the cervical spine. Pain and infection at the skull pin insertion site are common complications, but skull perforation is rare, and most published studies are case reports. This study aimed to identify risk factors for skull perforation by comparing patients who did and did not develop perforation.

Methods: Overall thickness and the thicknesses of the internal and external laminae of the skull at the skull pin insertion sites were measured on cranial computed tomography scans of 66 patients fitted with a halo vest. The results were compared between patients who did and did not develop perforation.

Results: Four patients developed perforations. All patients with perforation were older women, and their external and internal laminae were significantly thinner than those of patients who did not develop perforation.

Conclusion: The reported causes of skull pin perforation include infection around the pin, osteoporosis, and an enlarged frontal sinus. However, most patients with perforation in the present study were older women, and the cause was the thinning of the external and external laminae.

Background. Human pose estimation, a computer vision technique that identifies body parts and constructs human body representations from images and videos, has recently demonstrated high performance through deep learning. However, its potential application in clinical photography remains underexplored. This study aimed to establish photographic parameters for patients with adolescent idiopathic scoliosis (AIS) using pose estimation and to determine correlations between these photographic parameters and corresponding radiographic measures.

Methods. We conducted a study involving 42 patients with AIS who had undergone spinal correction surgery and conservative treatment. Preoperative photographs were captured using an iPhone 13 Pro mounted on a tripod positioned at the head of an X-ray tube. From the outputs of pose estimation, we derived five photographic parameters and subsequently conducted a statistical analysis to assess their correlations with relevant conventional radiographic parameters.

Results. In the sagittal plane, we identified significant correlations between photographic and radiographic parameters measuring trunk tilt angles. In the coronal plane, significant correlations were found between photographic parameters measuring shoulder height and trunk tilt and corresponding radiographic measurements.

Conclusions. The results suggest that pose estimation, achievable with common mobile devices, offers potential for AIS screening, early detection, and continuous posture monitoring, effectively mitigating the need for X-ray radiation exposure. Level of Evidence: 3.

Introduction: Despite that lateral lumbar interbody fusion (LLIF) is a minimally invasive surgery, some patients complain of severe site pain immediately after the surgery. This study aimed to explore the extent of perioperative pain after LLIF, compare the degree of perioperative pain after LLIF with that after other surgical procedures, and evaluate the factors associated with severe pain in the early postoperative period.

Methods: In this study, 93 patients who underwent lumbar spine surgeries for lumbar degenerative diseases were analyzed. The patients were categorized into three groups based on the surgical procedure: Group L, LLIF with percutaneous pedicle screw (PPS); Group P, posterolateral fusion (PLF) or posterior lumbar interbody fusion (PLIF); and Group D, posterior decompression (fenestration). The extent of low back pain was evaluated using the visual analog scale (VAS) preoperatively and from postoperative days 1 to 14.

Results: The VAS score for postoperative pain decreased in a time-dependent manner in all three groups (P < 0.01). Repeated measures analysis of variance (ANOVA) showed that the VAS in Group L was significantly higher than that in Group D (P < 0.01). Time point analysis revealed that the VAS scores from postoperative days 1 to 9 in Group L were significantly higher than those in Group D (P < 0.05). No significant difference was observed in the VAS scores of postoperative pain between Groups L and P on all postoperative days. The VAS score for early postoperative pain in Group L was significantly correlated with the change in disc height index (P < 0.05, r = 0.43) and tended to be associated with the grade of preoperative disc degeneration and the VAS score of preoperative low back pain (P = 0.076–0.19).

Conclusions: This study is the first to evaluate the factors associated with pain during the early postoperative period of LLIF. Although LLIF is a minimally invasive surgery, severe pain may develop in patients with significant preoperative disc degeneration or following spinal correction surgery.

Introduction: Chemonucleolysis with condoliase is a minimally invasive treatment option for lumbar disk herniation (LDH). However, studies reporting the efficacy of condoliase in patients aged <20 years are scarce. Therefore, the present study aimed to evaluate the efficacy of condoliase therapy for LDH in the aforementioned population.

Methods: Condoliase administration was determined based on adequate informed consent. The study enrolled 138 patients (mean age, 41.3 ± 15.4 years) with LDH who received condoliase injections with a follow-up period of 1 year. The patients were divided into Group Y (age, <20 years) and Group A (age, 20–70 years). The clinical outcomes were visual analog scale (VAS) scores for leg and back pain and Oswestry Disability Index (ODI) values. Changes in disk height and degeneration were evaluated. These data were obtained at baseline and at the 3-month and 1-year follow-ups. Condoliase therapy was considered to be effective if it improved the VAS score for leg pain by ≥50% at 1 year from baseline and prevented surgery.

Results: Groups Y and A consisted of 15 and 123 patients, respectively. Condoliase therapy was effective in 9 patients (60.0%) in Group Y and 96 patients (78.0%) in Group A. The rates of Pfirrmann grade deterioration and recovery were substantially higher in Group Y than in Group A (83.3% vs. 45.8% and 50.0% vs. 16.3%, respectively). While the disk height reduction in Group Y was greater at 3 months, it recovered to the same level as that in Group A at 1 year. In Group Y, patients who did not respond to the treatment exhibited a considerably higher preoperative ODI (P < 0.05).

Conclusions: Chemonucleolysis with condoliase is considered to have limited efficacy in patients aged <20 years. Caution should be taken when managing cases showing lumbar instability or existing disability. While chemonucleolysis with condoliase is a less invasive treatment option for LDH, the administration should be decided upon with sufficient consent considering the potential limited efficacy and disk degeneration.

Introduction: This study aimed to investigate the relationship between childbirth and lower back pain and determine the health-related quality of life of female patients with lower back pain.

Methods: A total of 111 patients were divided into three groups: those who had given birth and developed lower back pain due to pregnancy, childbirth, or child-rearing movements (childbirth group, n = 41), those who had given birth and developed lower back pain due to other causes (childbirth and other cause group, n = 29), and those who were nulliparous (nulliparous group, n = 41). A total of 22 physical therapists evaluated the patients during initial rehabilitation. Basic information and health-related quality of life were compared among the three groups using a one-way analysis of variance for the visual analog scale scores for lower back pain, summary scores (physical health [physical component summary] and mental health [mental component summary]), and subscales (physical functioning, role-physical, bodily pain, general health, vitality, social functioning, role-emotional, and mental health) of the Short Form-8 Health Survey. These values were also compared with the national standard values for health-related quality of life. The chi-square test of independence was used to compare distributions, and Fisher' s exact probability test was used for cells with an expected value of <5.

Results: Most participants had physical component summary scores below the national standard values. The visual analog scale scores for lower back pain were significantly higher in the birth group than in the nonbirth group. The physical component summary, physical functioning, and general health scores were significantly lower in the birth group than in the nonbirth group. Moreover, bodily pain scores were significantly lower in the birth group than in the other groups.

Conclusions: For female patients with lower back pain due to pregnancy, childbirth, or childcare activities, physical conditions unique to postpartum women should be considered, and if necessary, instructions for activities of daily living should be provided.