Introduction: Long-term radiographic changes of segmental partial laminectomy (SPL) in patients with cervical spondylotic myelopathy are not clear.

Materials: A retrospective cohort study was conducted. The primary outcomes were changes in 3 parameters (cervical lordosis, lordotic angle, and range of motion) between preoperative and 1, 3, 5, 8, and 10 years after surgery. The secondary outcomes were the presence of union of vertebral arches and fracture of the spinous process, and their influence on 3 parameters.

Results: A total of 111 patients underwent SPL from 1991 to 2016, with a mean age of 63.8 years, 65 males, and 46 females. There were no significant differences in 3 parameters between preoperative and 1, 3, 5, 8, and 10 years after surgery. Union of vertebraevertebral arches occurred in 14 of 111 patients (12.6%) and in 17 of 310 vertebral arches (5.5%), and there were no significant differences in 3 parameters between the union and non-union groups. Fracture of spinous processes occurred in 21 of 111 patients (18.9%) and in 42 of 428 spinous processes (9.8%), and there were no significant differences in 3 parameters between the fracture and non-fracture groups.

Conclusions: Cervical lordosis, lordotic angle, and range of motion were maintained for a long time after SPL. Union of vertebral arches and fracture of spinous processes had no effect on 3 parameters.

Introduction: Multimodal intraoperative neurophysiological monitoring (IONM) is recommended in spinal surgery to prevent postoperative neurological deficits. Spontaneous electromyographic activity (sEMG) can detect neural invasion in real time; however, its clinical significance remains insufficiently understood. This study aimed to clarify the characteristics of sEMG during cervical and thoracic spinal surgery.

Materials: We analyzed 119 cervical and 47 thoracic spinal surgeries performed in 2023 in which both transcranial motor evoked potentials (Tc-MEP) and sEMG were used. Patient demographics, IONM outcomes, and detailed sEMG characteristics were evaluated. sEMG was defined as activity lasting ≥5 seconds and clearly associated with surgical manipulation.

Results: Spontaneous electromyographic activity occurred in 53.8% of cervical and 46.8% of thoracic spinal surgeries. In cervical cases, sEMG was significantly more frequent in cases of ossification of the posterior longitudinal ligament (OPLL) and anterior surgical approaches. In thoracic cases, OPLL and spinal cord tumors showed particularly high sEMG incidences. sEMG most frequently occurred during decompression and tumor resection. Patients who developed postoperative motor deficits exhibited significantly higher sEMG amplitudes and involvement of a greater number of muscles simultaneously compared with those without deficits.

Conclusions: Spontaneous electromyographic activity frequently occurred in high-risk spinal surgeries, including cervical and thoracic OPLL and spinal cord tumor cases. While most sEMG appeared transient and reversible, high-amplitude and multi-muscle sEMG discharges were associated with postoperative motor deficits and should be interpreted with caution. sEMG is useful for monitoring nerve invasion in real time and providing feedback to the surgeon. IONM in combination with sEMG and Tc-MEP is expected to result in safer surgery.

Introduction: In corrective fixation for adult spinal deformity (ASD), the S2 alar iliac screw (S2AIS) is a useful fixation technique that can transmit corrective force directly to the pelvis. However, because S2AIS is inserted through the sacroiliac joint, there is concern about screw loosening and its effect on the sacroiliac joint. The purpose of this study was to evaluate the long-term effects of S2 alar iliac screw (S2AIS) loosening on the sacroiliac joint after corrective fusion surgery for ASD.

Methods: We retrospectively reviewed 38 patients (1 male, 37 females; mean age at surgery 73.5 years; mean follow-up 103 months) who underwent posterior corrective fusion from the thoracic spine to the sacrum using S2AIS between September 2013 and September 2019. Patients were divided into loosening (L) and non-loosening (N) groups based on radiological evidence of screw loosening (a radiolucent zone of 2 mm or more around S2AIS on computed tomography at 1 year postoperatively).

The following parameters were compared between groups: spinal sagittal alignment (SVA, PI, PT, TK, and LL), degenerative changes of the sacroiliac joint, chronological changes of screw loosening, and presence of postoperative sacroiliac joint pain confirmed by physical provocation tests (Newton and Gaenslen tests).

Results: S2AIS loosening occurred in 18 cases (47%), all bilaterally. There were no significant differences in age, body mass index, or bone mineral density between the groups. The preoperative PI was significantly higher in the L group, but other sagittal parameters showed no statistically significant differences. Progression of sacroiliac joint degeneration was observed in 22% of joints in the L group and 10% in the N group. No cases in the L group exhibited progressive enlargement of loosening after 1 year. Sacroiliac joint pain was noted in three cases per group, all mild and without impact on daily activity, and unrelated to the degree of articular degeneration.

Conclusions: Loosening of S2AIS did not progress over time and did not adversely affect sagittal alignment, sacroiliac joint integrity, or pain. These findings suggest that S2AIS loosening may preserve sacroiliac joint mobility without compromising long-term fixation stability or clinical outcomes after corrective fusion surgery for ASD.

Introduction: With the advent of a super-aged society, pharmacological treatment for osteoporosis has become widely implemented. However, nationwide studies on pharmacological treatment for patients with osteoporotic vertebral fractures remain limited. The aim of this study is to investigate the status of osteoporosis medication use before and after vertebral fracture among the elderly using a large-scale claims database.

Methods: A descriptive epidemiological study was conducted using an insurer database provided by DeSC Healthcare, which includes health insurance claims data for the elderly population. The study population consisted of newly diagnosed patients aged 75 years and older with vertebral fractures. We examined the prescription status of osteoporosis medications before and after the fracture.

Results: Of the 552,931 elderly patients with osteoporotic fractures, 265,301 patients with vertebral fractures were identified. The mean age was 84.2 years, and 72.9% were female. The proportion of patients prescribed osteoporosis medications was 44.6% before the fracture and 50.3% after the fracture. The breakdown of osteoporosis treatments showed that before fracture, the most common category was "no medication" (55.4%), followed by active vitamin D₃ (27.8%) and bisphosphonates (21.7%). After fracture, "no medication" remained the most common category (49.7%), followed by active vitamin D₃ (31.5%) and bisphosphonates (21.8%).

Conclusion: Among elderly patients with vertebral fractures, although the rate of pharmacological treatment for osteoporosis increased after the fracture, it remained insufficient.

Introduction: Adolescent idiopathic scoliosis (AIS) is typically considered asymptomatic, but some patients report preoperative pain. Psychological factors may contribute to this pain, although evidence is limited for Lenke type 1 curves.

Materials and Methods: This retrospective study included 212 patients with Lenke type 1 AIS who underwent posterior spinal fusion. We first analyzed the prevalence of preoperative pain and its association with clinical and radiographic factors. Subsequently, 57 patients with complete Scoliosis Research Society-30 (SRS-30) and Oswestry disability index (ODI) scores at three time points-preoperatively, at 2 years postoperative, and at final follow-up-were analyzed to assess the relationship between mental health and pain.

Results: Preoperative pain was present in 103 (48.6%) patients. There were no significant differences in age, sex, Cobb angle, lumbar modifier, or sagittal profile between patients with and without pain, although the pain group showed a trend toward reduced thoracic kyphosis. In the subgroup analysis, mental health scores on the SRS-30 positively correlated with pain scores at all time points and negatively correlated with ODI scores preoperatively and at the final follow-up. Moreover, preoperative mental health was a significant predictor of final pain and disability scores.

Conclusions: Nearly half of patients with AIS Lenke type 1 experienced preoperative pain, which was not associated with conventional radiographic parameters. Mental health, particularly, at the preoperative stage, was significantly associated with concurrent and long-term pain and functional outcomes. These findings highlight the importance of including psychosocial assessment and interventions in the preoperative management of patients with AIS.

Introduction: Magnetic resonance imaging (MRI) is the gold standard for diagnosing acute vertebral compression fractures (VCFs) due to its sensitivity to bone marrow edema (BME). However, its use may be limited by contraindications or patient-related factors such as severe pain or inability to remain still. Dual-Energy computed tomography (DECT), which has been developed in recent years, is a novel imaging technique capable of generating material decomposition images, including water density images that suppress calcium and enhance water content. These images enable visualization of intramedullary hemorrhage, which has been reported to be applicable for diagnosing acute VCFs. This study aimed to compare the diagnostic accuracy of DECT with MRI for detecting VCFs.

Methods: A retrospective analysis was conducted on 50 patients (mean age: 80.2 years) who presented with suspected VCFs between September 2023 and September 2024 and underwent DECT and MRI. Water density images from DECT were analyzed for the presence of BME and compared with MRI results to evaluate diagnostic accuracy.

Results: DECT showed a sensitivity of 75.0%, specificity of 71.4%, positive predictive value (PPV) of 87.0%, negative predictive value of 53.0%, false positive rate of 28.6%, false negative rate of 25.0%, positive likelihood ratio of 2.62, and negative likelihood ratio of 0.35. These results suggest that the presence of bone marrow edema on DECT water density images strongly correlates with vertebral compression fractures.

Conclusion: DECT offers a practical alternative for diagnosing acute VCFs, particularly, in emergency settings or when MRI is unavailable. Its high PPV supports its reliability in confirming fractures, although sensitivity is reduced in early-stage fractures where detection remains challenging.

Introduction: Kyphotic deformity after cervical laminoplasty is a well-known postoperative complication, but its preoperative prediction remains difficult. This study aimed to investigate preoperative alignment parameters as potential risk factors for postoperative kyphotic change.

Materials: We retrospectively analyzed 43 patients (36 males, 7 females; mean age 73.1 years) who underwent cervical laminoplasty for cervical spondylotic myelopathy at our institution between 2016 and 2024. Patients with preoperative kyphotic alignment were excluded. Patients were divided into two groups based on cervical sagittal alignment at 1 year postoperatively: those with C2-7 angle < 0° were defined as the kyphosis group and the others as the non-kyphosis group. Preoperative radiographic parameters-including C2-7 angle, extension/flexion Cobb angles, cervical range of motion (ROM), C7 slope, C7 slope-CL angle mismatch, and cervical sagittal vertical axis (cSVA) -were compared between the two groups. In addition, intraoperative factors and JOA recovery rates were analyzed. The correlation between preoperative extension Cobb angle and postoperative C2-7 angle change (ΔCobb) was assessed using Spearman correlation. A receiver operating characteristic (ROC) curve analysis was performed to determine the optimal cut-off value of extension Cobb angle for predicting kyphotic deformity. Patients were then stratified into two groups based on this cut-off value, and the kyphosis incidence rates were compared. Multivariate logistic regression was used to identify independent predictors of postoperative kyphosis.

Results: Postoperative kyphotic deformity occurred in 13 (30.2%) patients. The kyphosis group showed significantly lower preoperative C2-7 angle, extension Cobb angle, C7 slope, and JOA recovery rates than the non-kyphosis group (p<0.05). In the multivariate analysis, only the preoperative extension Cobb angle was identified as an independent predictor of postoperative kyphosis (p < 0.05). No significant correlation was observed between extension Cobb angle and ΔCobb (r=0.103, p = 0.51). The ROC analysis yielded a cut-off value of 17.0° (AUC = 0.80). Using this threshold, the incidence of kyphosis was significantly higher in patients with extension Cobb angle < 17° (58.3%) than those with ≥ 17° (19.4%) (p < 0.05).

Conclusions: Preoperative extension Cobb angle was an independent predictor of kyphotic deformity after cervical laminoplasty, with an optimal cut-off value of 17.0°. This parameter may be a useful tool in preoperative assessment and surgical planning.

Introduction: Determination of bone union is a fundamental issue in the treatment of osteoporotic vertebral fractures (OVFs). It is likely that OVFs without visually detectable vertebral mobility (V-mobility: a difference in vertebral height on sitting or standing and supine radiographs) are considered radiographically united without reference to a cutoff value of V-mobility to determine bone union in clinical practice. The present study aimed to estimate a V-mobility cutoff value to determine radiographic bone union on sitting and supine radiographs.

Methods: Lateral radiographs of the thoracolumbar vertebrae from T11 to L2 in 45 OVFs were obtained from 27 OVF patients (22 women, 5 men; mean age, 81 years). V-mobility was measured in 0.1 mm units on lateral radiographs in sitting and either lateral decubitus or supine positions in this study. Lateral radiographs to detect V-mobility were selected according to the grade of V-mobility. Stable vertebrae were defined as fractured vertebrae without visually detectable V-mobility on radiographs. Two observers visually assessed OVFs as stable or unstable on radiographs twice, with an interval of more than 1 week. Each observer reevaluated only OVFs in which the determinations differed between the two timepoints. Another observer examined OVFs with different determinations between the two observers to obtain a final determination for this study. Intraobserver and interobserver reproducibility were assessed by kappa statistics. The cutoff value of V-mobility to determine fracture status (stable or unstable) of OVFs was estimated by receiver operating characteristic curve analysis.

Results: The V-mobility cutoff value to determine fracture status of OVFs was an anterior vertebral height (Ha; mm) of 1.9 mm. The area under the curve was 0.918 (95% CI: 0.825-1.011, p < 0.001), indicating high accuracy. The sensitivity and specificity were 0.900 and 0.867, respectively. The kappa statistics of intraobserver reproducibility values of the two observers were 0.906 (95% CI: 0.777-1.034, p < 0.001) and 0.8004 (95% CI: 0.615-0.986, p < 0.001), with excellent and good agreement, and that of interobserver reproducibility was 0.657 (95% CI: 0.428-0.887, p < 0.001), with good agreement.

Conclusions: The V-mobility cutoff value to determine fracture status (stable or unstable) of OVFs was 1.9 mm in Ha, with high accuracy in receiver operating characteristic curve analysis. Accordingly, it is likely that OVFs with V-mobility of ≤ 1.9 mm in Ha on sitting and supine radiographs may be determined to have achieved bone union.

Introduction: Surgical procedures using spinal instrumentation, such as percutaneous pedicle screws and minimally invasive iliac screws, have recently become a common treatment for pelvic ring fractures. The outcomes of this treatment are reported, and the efficacy is evaluated.

Methods: Twenty-three patients who underwent 27 pelvic ring fracture repair procedures using spinal instrumentation at our hospital were included in the study. The fracture types were classified as follows: AO B1, three cases; B2, two cases; B3, 11 cases; C1, 1 case; C2, five cases; and C3, one case. The surgical procedures were as follows: minimally invasive Galveston method, seven cases; crab-shaped fixation, 11 cases; trans-iliac rod fixation, three cases; and minimally invasive anterior pelvic internal fixator (INFIX), including dual INFIX, six cases. The evaluation criteria were operative time, intraoperative blood loss, and bone union.

Results: The average operative time was two hours and 11 minutes with an average blood loss of 332 mL. When the five cases that required additional surgical procedures (two cases required exposure of the fracture site due to complete anterior dislocation of the sacroiliac joint, one case required removal of spinal bone fragments, one case required connection to existing spinal instrumentation, and one case required simultaneous fixation of multiple lumbar fractures) were excluded, the average operative time was two hours and one minutes with an average blood loss of 221 mL. The average operative time for each surgical procedures was as follows: minimally invasive Galveston method, two hours and 43 minutes (maximum, three hours and eight minutes); crab-shaped fixation, two hours and 6 minutes (maximum, two hours and 28 minutes); trans-iliac rod fixation, one hour and 31 minutes (maximum, one hour and 37 minutes); and INFIX, including dual INFIX, one hour and 20 minutes (maximum, one hour and 40 minutes). The operative time did not exceed the average operating time for each procedure by more than 25 minutes. Bone union was achieved in all 21 patients who had follow-up evaluations > six months.

Conclusion: Surgical treatment using spinal instrumentation for pelvic ring fractures is minimally invasive and provides adequate fixation. A major advantage of this procedure is the low variability in operative time. This feature is particularly beneficial for this type of trauma, where multiple surgical sites are often required due to multiple injuries.

Introduction: The typical symptoms of cervical myelopathy primarily include numbness and motor disturbance in the extremities. However, there are some rare cases in which the lesion is confined to the cervical spinal cord, and symptoms in the lower extremities are clearly present, but symptoms in the upper extremities are absent. The absence of symptoms in the upper extremities makes these cases difficult to diagnose. At our hospital, we have often experienced improvement in symptoms after performing cervical spine surgery on such cases. The purpose of this study was to clarify characteristics of the subjective symptoms and clinical and imaging findings by reviewing a series of these cases.

Methods: Of the 344 cases that underwent cervical spine surgery at our hospital, 27 cases (7.8%) in which no clear upper extremity symptoms were observed were selected for this study. 9 cases (2.6%) underwent cervical spine surgery only, while 18 cases (5.2%) had lesions in the thoracolumbar spine and underwent simultaneous thoracolumbar spine surgery.

Results: The average age of the subjects was 74±8.8 years (54-90 years), with 20 males and 7 females. None of the cases had reported upper limb symptoms preoperatively, but 10 cases reported improvement in upper extremity movement postoperatively. All cases reported some symptoms in the lower extremities preoperatively, and except for one case, improvement in the symptoms was observed postoperatively. The levels of cervical spinal cord compression were as follows: one case (3.7%) with C6/7 alone, 17 cases (63%) with multi-level compression including C6/7, and 9 cases (33.3%) with multi-level compression above C5/6.

Conclusions: This study suggested that there were some cases of cervical myelopathy in which only symptoms in the lower extremities are present without symptoms in the upper extremities.

Introduction: Epidural hematoma causing spinal cord compression after spinal surgery is a rare but severe complication that may cause profound motor paralysis. Because neurological prognosis is closely tied to the time to hematoma evacuation, prompt decompression is critical. However, immediate surgery under general anesthesia is often delayed by the need to secure an operating room, induce anesthesia, and complete preoperative preparations, especially at night, on holidays, or soon after the patient has eaten. To address this, we implemented a two-step salvage operation: rapid bedside hematoma evacuation under local anesthesia, followed by definitive surgical management under general anesthesia. Here, we report our experience with this approach in three cases of acute severe motor paralysis after spinal surgery.

Case Report: Acute complete motor paralysis developed in three patients (a 78-year-old man and 62-year-old man with cervical ossification of the posterior longitudinal ligament [OPLL], and an 84-year-old woman with thoracic ossification of the ligamentum flavum [OYL]) within hours of decompressive spinal surgery. The time from initial surgery to detection of paralysis ranged from 1 hour 21 minutes to 3 hours 12 minutes. In all cases, immediate wound opening and hematoma evacuation were performed at the bedside under local anesthesia. The procedures were performed with the patient in prone or lateral position, using aseptic technique with skin disinfection, gowning, and portable lighting. All patients showed immediate neurological improvement after hematoma evacuation. One patient had recurrent paralysis on the same day and required a second evacuation and delayed wound closure under general anesthesia. The other two underwent definitive wound closure and hemostasis in the operating room under general anesthesia on the same day. No postoperative neurological deterioration or wound infection occurred in any case.

Conclusions: In these three cases of severe postoperative paralysis due to epidural hematoma, a two-step salvage operation-immediate bedside hematoma evacuation under local anesthesia, followed by definitive management under general anesthesia-produced rapid neurological recovery without complications. Shortening the interval from paralysis onset to decompression was critical for favorable outcomes. This method bypasses delays associated with operating room and anesthesia preparation, making it suitable for emergency situations. With proper diagnosis, sterile technique, and a standardized protocol, this approach can be safely performed and may serve as a valuable option for spinal surgeons treating acute postoperative paralysis due to epidural hematoma.