Background: Idiopathic spinal cord herniation (ISCH) is a rare condition that is characterized by ventral herniation of the spinal cord through a defect in the dura mater into the epidural space, with no identifiable cause. ISCH is frequently underdiagnosed, and the information available in case reports is limited. To provide an overview of the clinical manifestations and diagnosis of this condition, this study aims to conduct a review of reported cases of ISCH.

Methods: A literature review was carried out using seven databases. The search was conducted using the keywords "Idiopathic spinal cord herniation" OR "Idiopathic Ventral Spinal Cord Herniation" AND "Case report" OR "case series."

Results: A total of 92 relevant papers reporting 224 cases, besides the index case, were determined. Of the cases, 58.5% were females and the mean age was 50.7 (SD 13.2) years. Symptoms, diagnoses, and outcomes were similar between genders. The most common clinical signs included motor symptoms (82.6%), instability (61.3%), hypoesthesia (59.2%), and disturbance of thermal sensitivity (47.3%). Brown-Séquard syndrome was observed in 27.2% of the cases, and surgical treatment was employed in 89.7% of the cases.

Conclusions: ISCH is a pathology that is principally treated with surgical approach. This study provides valuable insights into the clinical manifestations and diagnosis of ISCH, which can aid in the early recognition and treatment of this rare condition.

The major symptoms of lumbar disc herniation (LDH) are low back pain, radiative lower extremity pain, and lower limb movement disorder. Patients with LDH suffer from great distress in their daily life accompanied by severe economic hardship and difficulty in self-care, with an increasing tendency in the aging population. PubMed and the Cochrane Central Register of Controlled Trials were searched for relevant studies of spontaneous resorption or regression in LDH after conservative treatment and for other potential studies, which included those from inception to June 30, 2023. The objective of this narrative review is to summarize previous literatures about spontaneous resorption in LDH and to discuss the mechanisms and influencing factors in order to assess the probability of spontaneous resorption by conservative treatment. Spontaneous resorption without surgical treatment is influenced by the types and sizes of the LDH, inflammatory responses, and therapeutic factors. If the lumbar disc herniated tissue comprises a higher percentage of cartilage or modic changes have been shown on magnetic resonance imaging (MRI), resorption in LDH is prevented. The bull's eye sign on enhanced MRI, which is a ring enhancement around a protruding disc, is a vital indicator for easy reabsorption. In addition, the type of extrusion and sequestration in LDH could forecast the higher feasibility of natural reabsorption. Moreover, the higher the proportion of protrusion on the intervertebral disc tissue within the spinal canal, the greater the likelihood of reabsorption. Therefore, which illustrates the feasibility of conservative treatments for LDH. Nonsurgical management of LDH with clinical symptoms is recommended by the authors.

The incidence of spontaneous or primary spondylodiscitis has been increasing over the years, affecting the aging population with multiple comorbidities. Several conditions influencing treatment outcomes stand out, such as diabetes mellitus, renal insufficiency, cardiovascular and respiratory dysfunction, and malnutrition. Due to these, the question arises regarding properly managing their current conditions and pre-existing disease states. Treatment plans must consider all concomitant comorbidities rather than just the infectious process. This can be done with the help of multidisciplinary teams to provide comprehensive care for patients with pyogenic spondylodiscitis. To date, there is no article regarding comprehensive medicine for spontaneous pyogenic spondylodiscitis; hence, this paper reviews the evidence available in current literature, recognizes knowledge gaps, and suggests comprehensive care for treating patients with spinal infections.

Pre-requisites for implementing multidisciplinary teams include leadership, administrative support, and team dynamics. This group comprises an appointed leader, coordinator, and different subspecialists, such as orthopedic surgeons, infectious disease specialists, internists, rehabilitation doctors, psychiatrists, microbiologists, radiologists, nutritionists, pharmacologists, nurses, and orthotists working together with mutual trust and respect.

Employing collaborative teams allows faster time for diagnosis and improves clinical outcomes, better quality of life, and patient satisfaction. Forefront communication is clear and open between all team members to provide holistic patient care. With these in mind, the need for employing multidisciplinary teams and the feasibility of its implementation emerges, showing a promising and logical path toward providing comprehensive care in managing multimorbid patients with pyogenic spondylodiscitis.

Background: Tranexamic acid (TXA) has gained popularity in spinal surgery because of its potential to reduce blood loss. However, concerns regarding its safety and efficacy remain.

This systematic review and meta-analysis aimed to evaluate the efficacy of TXA in reducing blood loss and its safety profile in spinal surgeries.

Methods: A comprehensive search was conducted in electronic databases for randomized controlled trials and prospective studies evaluating the use of TXA in spinal surgery. The primary outcomes were intraoperative and total estimated blood loss (EBL), and the secondary outcomes included the incidence and types of complications associated with TXA use. Meta-analyses were performed using random-effects models.

Results: Thirteen studies involving 1,213 participants were included in the meta-analysis. The use of TXA was associated with significant reductions in both intraoperative (mean difference: −46.56 mL [−73.85, −19.26], p<0.01]) and total EBL (mean difference: −210.17 mL [−284.93, −135.40], p<0.01) while also decreasing the need for blood transfusions (risk ratio: 0.68 [0.51, 0.90], p<0.01). No significant difference was found in the incidence and types of thrombotic complications when TXA was used in spinal surgery. Subgroup analysis showed consistent results in instrumentation and fusion surgery and different doses of TXA.

Conclusions: TXA is effective in reducing intraoperative and overall blood loss in spinal surgery without increasing the risk of complications. These findings support the use of TXA to improve patient outcomes. However, caution should be exercised because of the heterogeneity among the included studies. Further research is needed to confirm these findings and explore potential long-term complications.

Introduction: The incidence of hyponatremia after orthopedic surgery is high. Hyponatremia may prolong hospitalization and increase mortality, but few reports have identified risk factors for hyponatremia after spinal surgery. This study aims to determine the incidence and risk factors for hyponatremia after spinal surgery.

Methods: A total of 200 patients aged 20 years or older who underwent spinal surgery at our hospital from 2020-2021 were recruited. Data on age, sex, height, weight, body mass index, operation duration, blood loss, albumin level, the geriatric nutritional risk index (GNRI), potassium level, the estimated glomerular filtration rate (eGFR), sodium level, length of hospital stay, history of hypertension, dialysis status, the occurrence of delirium during hospital stay, and oral medication use were collected. Comparisons between the postoperative hyponatremia group and the postoperative normonatremia group were conducted to evaluate the impact of hyponatremia on clinical outcomes.

Results: Postoperative hyponatremia was observed in 56 (28%) of the 200 patients after spinal surgery. Comparison between the postoperative hyponatremia group with the postoperative normonatremia group revealed that the patients in the postoperative hyponatremia group were significantly older (72 versus 68.5 years, p<0.01). Postoperative hyponatremia was significantly associated with low GNRI values (100.8 versus 109.3, p<0.01), low eGFR values (59.2 versus 70.8 mL/min/1.73 m², p<0.01), preoperative hyponatremia (138.5 vs. 141 mEq/L, p<0.01), and a high incidence of delirium (12.5% versus 2.7%, p=0.01). Older age (odds ratio=1.04, p=0.01) and preoperative hyponatremia (odds ratio=0.66, p value<0.01) were risk factors for postoperative hyponatremia.

Conclusions: In addition to older age and preoperative hyponatremia, the study identified new risk factors for postoperative hyponatremia, which are preoperative undernutrition and impaired renal function. The incidence of delirium was significantly higher in the postoperative hyponatremia group, suggesting that correcting preoperative hyponatremia and ensuring good nutrition may prevent delirium and thereby shorten hospital stays.

Introduction: In this study, we aim to describe the radiological characteristics of degenerative cervical kyphosis (DCK) with cervical spondylotic myelopathy (CSM) and discuss the relationship between DCK and the pathogenesis of spinal cord dysfunction.

Methods: In total, 90 patients with CSM hospitalized in our center from September 2017 to August 2022 were retrospectively examined in this study; they were then divided into the kyphosis group and the nonkyphosis group. The patients' demographics, clinical features, and radiological data were obtained, including gender, age, duration of illness, cervical Japanese Orthopaedic Association (JOA) score, cervical lordosis (CL), height of intervertebral space, degree of wedging vertebral body, degree of osteophyte formation, degree of disc herniation, degree of spinal cord compression, and anteroposterior diameter of the spinal cord. In the kyphosis group, kyphotic segments, apex of kyphosis, and segmental kyphosis angle were recorded. Radiological characteristics between the two groups were also compared. Correlation analysis was performed for different spinal cord compression types.

Results: As per our findings, the patients in the kyphosis group showed more remarkable wedging of the vertebral body, more severe anterior compression of the spinal cord, and a higher degree of disc herniation, while the posterior compression of the spinal cord was relatively mild when compared with the nonkyphosis group. CL was related to the type of spinal cord compression, as cervical kyphosis is an independent risk factor for anterior spinal cord compression.

Conclusions: DCK might play a vital role in the pathogenesis of spinal cord dysfunction. In patients with DCK, it was determined that the anterior column is less supported, and more severe anterior spinal cord compression is present. The anterior approach is supposed to be preferred for CSM patients with DCK.

Introduction: The Scoliosis Research Society-30 (SRS-30) is a questionnaire originally developed from the SRS-22r questionnaire and is used to evaluate adolescent idiopathic scoliosis (AIS). It comprised questions on five domains: function, pain, self-image, mental health, and satisfaction, with seven additional questions related to postoperative aspects. In addition to the original English version, translations in multiple languages have been effectively applied. Herein, we evaluated the internal consistency and external validity of the Japanese version of the SRS-30 for AIS patients.

Methods: Among the 30 questions in SRS-30, the eight additional questions from SRS-22r were translated and back-translated to create a Japanese version of the SRS-30. This translated questionnaire was then used to survey patients with AIS who underwent corrective fusion surgery one year postoperatively. The internal consistency of the responses was evaluated using the Cronbach α coefficient. Additionally, the Spearman correlation analyses were conducted to assess the correlation between the scores obtained from the SRS-30 Japanese version and SRS-22r and the Oswestry Disability Index (ODI) for the overall scale and the five domains.

Results: A total of 81 cases (eight males and 73 females; mean age at surgery 14.4 years) were enrolled. The mean preoperative Cobb angle was 51.0°. The Cronbach α coefficient for the overall SRS-30 was 0.861, indicating high internal consistency, while the coefficients for each domain were as follows: function/activity, 0.697; pain, 0.405; self-image/appearance, 0.776; mental health, 0.845; and satisfaction, 0.559. The SRS-30 total score significantly correlated with the SRS-22r total (r=0.945, P<0.001) and the ODI (r=−0.511, P<0.001). The SRS-30 domains highly correlated with the corresponding SRS-22r domains, with correlations ranging from r=0.826 to 0.901 (all P<0.001).

Conclusions: The Japanese version of the SRS-30 demonstrated good internal and external validity. The SRS-30 can be used as an assessment tool for health-related quality of life in AIS patients.

Introduction: Locomotive syndrome caused by degenerative musculoskeletal diseases is reported to improve with surgical treatment. However, it is unclear whether surgical treatment is effective for the locomotive syndrome developing in patients with degenerative cervical myelopathy (DCM). Thus, this study primarily aimed to longitudinally assess the change in locomotive syndrome stage before and after cervical spinal surgery for patients with DCM using the 25-question geriatric locomotive function scale (GLFS-25). A secondary objective was to identify factors associated with the postoperative improvement in the locomotive syndrome stage.

Methods: We retrospectively reviewed clinical data of patients undergoing cervical spine surgery at our institution from April 2020 to May 2022 who had answered the Japanese Orthopaedic Association Cervical Myelopathy Assessment Questionnaire, visual analog scale, and GLFS-25 preoperatively and at 6 months and 1 year postoperatively. We collected demographic data, medical history, preoperative radiographic parameters, presence or absence of posterior longitudinal ligament ossification, and surgical data.

Results: We enrolled 115 patients (78 men and 37 women) in the present study. Preoperatively, using the GLFS-25, 73.9% of patients had stage 3, 10.4% had stage 2, 9.6% had stage 1, 6.1% had no locomotive syndrome. The stage distribution of locomotive syndrome improved significantly at 6-months and 1-year postoperatively. The multivariable Poisson regression analysis revealed that better preoperative lower extremity function (relative risk: 3.0; 95% confidence interval: 1.01-8.8) was significantly associated with postoperative improvement in the locomotive syndrome stage.

Conclusions: This is the first study to longitudinally assess the locomotive syndrome stage in patients with DCM using GLFS-25. Our results indicated that patients with DCM experienced significant improvement in the locomotive syndrome stage following cervical spine surgery. Particularly, the preoperative lower extremity function was significant in postoperative improvement in the locomotive syndrome stage.

Introduction: To analyze the reliability of the newly developed patient-specific Screw Guide Template (SGT) system as an intraoperative navigation device for spinal screw insertion.

Methods: We attempted to place 428 screws for 51 patients. The accuracy of the screw track was assessed by deviation of the screw axis from the preplanned trajectory on postoperative CT. The safety of the screw insertion was evaluated by the bone breach of the screw. The bone diameter available for screw trajectory (DAST) was measured, and the relations to the bone breach were analyzed.

Results: In the inserted screws, 98.4% were defined as accurate, and 94.6% were contained in the target bone. In the cervical spine, the screw deviation between breaching (0.57 mm) and contained screws (0.43 mm) did not significantly differ, whereas DAST for breaching screws (3.62 mm) was significantly smaller than contained screws (5.33 mm) (p<0.001). Cervical screws with ≥4.0 mm DAST showed a significantly lower incidence of bone breach (0.4%) than ≤3.9 mm DAST (28.3%) (p<0.001). In the thoracic spine, screw deviation and DAST had significant differences between breaching (1.54 mm, 4.41 mm) and contained (0.75 mm, 6.07 mm) (p<0.001). The incidence of the breach was significantly lower in thoracic screws with ≥5.0 mm (1.9%) than ≤4.9 (21.9%) DAST (p<0.001).

Conclusions: This study demonstrated that our SGT system could support precise screw insertion for 98.4% accuracy and 94.6% safety. DAST was recommended to be ≥4.0 and ≥5.0 mm in the cervical and thoracic spines for safe screw insertion.

Introduction: Previous research has demonstrated that mid- to long-term health-related quality of life following corrective fusion surgery for adult spinal deformity (ASD) can be improved by appropriate revision surgery. In this study, we aim to compare the cost-effectiveness of corrective fusion surgery for ASD with and without unexpected revision surgery 5 years postoperatively.

Methods: In total, 79 patients with ASD (mean age, 68.7 years) who underwent corrective fusion surgery between 2013 and 2015 were included in this study. Cost-effectiveness was evaluated based on the cost of obtaining 1 quality-adjusted life year (QALY). Patients were divided into two groups according to the presence or absence of unexpected revision surgery following corrective fusion and were subjected for comparison.

Results: As per our study findings, 26 (33%) of the 79 ASD patients underwent unexpected revision surgery during the first 5 years following surgery. Although there was no significant difference in terms of inpatient medical costs at the time of initial surgery for 5 years after surgery between the two groups (no-revision group, revision group; inpatient medical costs at the time of initial surgery: USD 69,854 vs. USD 72,685, P=0.344), the total medical expenses up to 5 years after surgery were found to be higher in the revision group (USD 72,704 vs. USD 104,287, P<0.001). The medical expenses required to improve 1 QALY 5 years after surgery were USD 178,476 in the no-revision group, whereas it was USD 222,081 in the revision group.

Conclusions: Although the total medical expenses were higher in the revision group, no significant difference was observed in the cumulative QALY improvement between the revision and no-revision groups. Moreover, the medical expenses required to improve 1 QALY were higher in the revision group, with a difference of approximately 20%.

Introduction: Precise prediction of hospital stay duration is essential for maximizing resource utilization during surgery. Existing lumbar spinal stenosis (LSS) surgery prediction models lack accuracy and generalizability. Machine learning can improve accuracy by considering preoperative factors. This study aimed to develop and validate a machine learning-based model for estimating hospital stay duration following decompression surgery for LSS.

Methods: Data from 848 patients who underwent decompression surgery for LSS at three hospitals were examined. Twelve prediction models, using 79 preoperative variables, were developed for postoperative hospital stay estimation. The top five models were chosen. Fourteen models predicted prolonged hospital stay (≥14 days), and the most accurate model was chosen. Models were validated using a randomly divided training sample (70%) and testing cohort (30%).

Results: The top five models showed moderate linear correlations (0.576-0.624) between predicted and measured values in the testing sample. The ensemble of these models had moderate prediction accuracy for final length of stay (linear correlation 0.626, absolute mean error 2.26 days, standard deviation 3.45 days). The c5.0 decision tree model was the top predictor for prolonged hospital stay, with accuracies of 89.63% (training) and 87.2% (testing). Key predictors for longer stay included JOABPEQ social life domain, facility, history of vertebral fracture, diagnosis, and Visual Analogue Scale (VAS) of low back pain.

Conclusions: A machine learning-based model was developed to predict postoperative hospital stay after LSS decompression surgery, using data from multiple hospital settings. Numerical prediction of length of stay was not very accurate, although favorable prediction of prolonged stay was accomplished using preoperative factors. The JOABPEQ social life domain score was the most important predictor.

Introduction: Recently, patient satisfaction has gained prominence as a crucial measure for ensuring patient-centered care. Furthermore, patient satisfaction after lumbar spinal canal stenosis (LCS) surgery is an important metric for physician's decision of surgical indication and informed consent to patient. This study aimed to elucidate how patient satisfaction changed after LCS surgery to identify factors that predict patient dissatisfaction.

Methods: We retrospectively reviewed time-course data of patients aged ≥40 years who underwent LCS surgery at multiple hospitals. The participants completed the Zurich Claudication Questionnaire (ZCQ) and the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ) before surgery and then 6 months and 1 year postsurgery. Patient satisfaction was categorized according to the postoperative score of the satisfaction domain of the ZCQ: satisfied, score ≤2.0; moderately satisfied, 2.0< score ≤2.5; and dissatisfied, score >2.5.

Results: The study enrolled 241 patients. Our data indicated a satisfaction rate of around 70% at 6 months and then again 1 year after LCS surgery. Among those who were dissatisfied 6 months after LCS surgery, 47.6% were more satisfied 1 year postsurgery. Furthermore, 86.2% of those who were satisfied 6 months after LCS surgery remained satisfied at 1 year. Multivariable analysis revealed that age (relative risk, 0.5; 95% confidence interval, 0.2-0.8) and preoperative score of psychological disorders on the JOABPEQ (relative risk, 0.2; 95% confidence interval, 0.03-0.08) were significantly associated with LCS surgery dissatisfaction. In addition, the receiver operating characteristic curve analysis revealed that the cutoff value for the preoperative score of psychological disorder of the JOABPEQ was estimated at 40 for LCS surgery dissatisfaction.

Conclusions: Age and psychological disorders were identified as significant predictors of dissatisfaction, with a JOABPEQ cutoff value providing potential clinical applicability.

Introduction: Studies describing the relationship between the hip and spine have reported that corrective spinal surgery for adult spinal deformity (ASD) affects the orientation of the acetabulum. However, the extent to which spinal correction in ASD affects acetabular anteversion in the standing position is unclear, especially after total hip arthroplasty, for which dislocation is a concern. The purpose of this study was to evaluate changes in anterior acetabular coverage in the upright position due to extensive correction surgery for ASD.

Methods: Thirty-six consecutive patients who had undergone spinal corrective surgery from the thoracolumbar region to the pelvis were enrolled and evaluated. The ventral-central-acetabular (VCA) angle and anterior acetabular head index (AAHI) were measured with a false-profile view to evaluate the relationship between acetabular anteversion in the standing position and spinopelvic parameters before and after surgery. The spinopelvic parameters measured included thoracic kyphosis, pelvic incidence, pelvic tilt (PT), sacral slope, lumbar lordosis (LL), sagittal vertical axis, and global tilt.

Results: The VCA angle and AAHI were significantly increased after spinal deformity correction (p<0.001). The changes in LL and PT were correlated with the VCA angle (LL: right, ρ=0.56; left, ρ=0.55, p<0.001; PT: right, ρ=−0.59; left, ρ=−0.64, p<0.001) and AAHI (LL: right, ρ=0.51; left, ρ=0.58, p<0.01; PT: right, ρ=−0.52; left, ρ=−0.59, p<0.01), respectively. Linear regression analysis revealed that a 10° increase in LL results in 1.4°-1.9° and 1.6%-2% increases in the VCA angle and AAHI, respectively.

Conclusions: Surgical correction for ASD significantly affects sagittal spinopelvic parameters, resulting in increased acetabular anteversion. The anterior coverage of the acetabulum in the postoperative standing position could be predicted with the intraoperatively measured LL, and evaluation using a false-profile was considered useful for treating ASD, particularly in patients after total hip arthroplasty.