Spine Surgery and Related Research最新文献

Introduction: To evaluate the differences in anterior spinal bridging and sagittal spinal parameters between patients with diffuse idiopathic skeletal hyperostosis (DISH) and ankylosing spondylitis (AS) using whole-spine computed tomography (CT).

Methods: This retrospective study included patients with DISH (n=111) and AS (n=27). The number of anterior spinal bridges and sagittal spinal parameters was evaluated. The sagittal vertical axis (SVA) evaluated by whole-spine CT was defined as sup-SVA. Patients were further evaluated by matching their age and sex.

Results: Anterior spinal bridging frequently occurred in the thoracic spine in DISH and AS. In AS, bridging occurred in the lumbar spine according to the number of anterior spinal bridges. Sup-SVA and T5-T12 thoracic kyphosis (TK) were significantly greater in AS, and lumbar lordosis (LL) was significantly smaller in AS. TK was greater according to the number of anterior spinal bridges in both DISH and AS. Sup-SVA in DISH was greater according to the number of anterior spinal bridges, especially in the thoracic spine, whereas it was greater according to the lumbar in AS. LL in AS was smaller according to the number of lumbar bridges. Sup-SVA in DISH correlated with TK, whereas it correlated with both TK and LL in AS.

Conclusions: In patients with AS, the spine tends to bridge from the lumbar to the thoracic spine, causing kyphosis in the thoracolumbar spine. In patients with DISH, the spine tends to bridge from the thoracic spine, causing kyphosis in the thoracic spine. Thus, sup-SVA is greater in AS than in DISH.

Introduction: This study aimed to identify the factors associated with the postoperative deterioration of sagittal balance after surgery for adult spinal deformity (ASD), focusing on preoperative alignment and pelvic incidence (PI).

Methods: We retrospectively reviewed the medical records of 87 patients who underwent corrective surgery for ASD (2017-2020). Sagittal balance was assessed using the sagittal balance classification (SBC). The patients were classified as balanced (maintained SBC grade 1 or 2) or imbalanced (deteriorated to grade 3). Radiographic parameters, clinical outcomes (Japanese Orthopedics Association scores and mechanical complications), and bone mineral density were analyzed.

Results: In 15 patients (17.2%), the sagittal balance deteriorated to grade 3 (imbalanced group). Factors significantly associated with postoperative deterioration of sagittal balance included preoperative grade 3 SBC (73.3% vs. 23.6%, p<0.001), steroid use (26.7% vs. 2.8%, p<0.01), pelvic fusion (80% vs. 51.4%, p=0.049), higher preoperative PI, sacral slope, and sagittal vertical axis. At 2 years, the imbalanced group showed a significantly greater corrective loss of the lumbar spine. Receiver operating curve analysis identified preoperative PI ≥52.1° as predictive of postoperative imbalance (sensitivity 86.7%, specificity 66.7%). The clinical outcomes were similar, but the reoperation rates were higher in the imbalanced group (20.0% vs. 2.8%, p=0.03).

Conclusions: High preoperative PI, severe sagittal imbalance, steroid use, and pelvic fusion were predictive of postoperative sagittal balance deterioration, underscoring the need for personalized preoperative planning.

Introduction: Endoscopic spine surgery (ESS) presents advantages over traditional microscopic techniques but faces limitations in terms of field of view and depth perception. Virtual reality (VR) devices offer solutions by integrating real-time digital images into the surgical field, enabling magnification and teleproctoring.

Methods: The study was conducted in two phases. In the first phase, 55 surgeons completed a pre-use questionnaire. In the second phase, 19 surgeons participated in cadaveric practical training using the device and completed a post-use survey. Data were analyzed using R software.

Results: Following device use, surgeon confidence in magnification increased significantly (from 21% to 57%), with improved perception of image quality. Acceptance of teleproctoring rose from 33% to 94.7%. The device was considered superior to the operating microscope in both image quality and ergonomics.

Conclusions: VR head-mounted devices enhance visualization in ESS, allow intraoperative access to imaging, and support remote guidance via teleproctoring. Their adoption may contribute to improved training, planning, and surgeon ergonomics. However, additional controlled studies are required to determine their effects on clinical outcomes and operative performance.

Introduction: Surgical decompression is necessary for anterior paradiscal-type thoracic spine tuberculosis with a neurological deficit; nevertheless, if pedicle screw fixation is unsuccessful, laminectomy may result in pan-vertebral instability. No available studies compare traditional anterolateral decompression (ALD) with the convenient, less extensive technique of transpedicular decompression (TPD).

Methods: This randomized comparative study of 20 cases of thoracic spine tuberculosis (T2-T12) used a posterior midline surgical approach with pedicle screw instrumentation. Diseased pedicle removal by eggshell technique (TPD) was compared with decompression by removal of the posterior part of the rib, transverse process, pedicle, and posterolateral part of the diseased vertebral body (ALD).

Results: Both groups had similar lengths of skin incision, intraoperative blood loss, and blood transfusion, but the duration of surgery was significantly less (p-value 0.019) in the TPD (156.5 minutes) than in the ALD group (184.5 minutes). Additional hemi-laminotomy was needed in two cases of TP, in the absence of liquid pus. Both groups showed similar neurological recovery except for one case of multidrug resistance in the ALD group. Improvements in the modified Japanese Orthopedics Association score (p=0.719); visual analog scale (p=0.259) and Nurick scale (p=0.387) had no statistical difference between the two groups. Mean kyphosis correction of 6.64⁰ and 6.45⁰ and mean loss of correction at 2-years were 4.74⁰ and 1.98⁰ in the TPD and ALD groups, respectively. Complications included one case of surgical site infection in each group.

Conclusions: Similar outcomes of both approaches. TPD is quicker but may need hemi-laminotomy in the absence of liquid pus. ALD enables thick organized pus removal without compromising lamina in paradiscal-tuberculosis.

Introduction: Herniated lumbar intervertebral discs migrate into the rostral or caudal anterior epidural space (AES). Previous studies have reported varying frequencies of migration direction, and the factors influencing the migration direction include patient age, affected disc level, and AES structural differences. However, the relationship between AES volume and migration direction remains unclarified. The purpose of this study was to measure the AES volume using computed tomography (CT) imaging and investigate the factors affecting herniated nucleus pulposus (HNP) migration in the sagittal direction.

Methods: We reviewed 42 patients who were surgically treated for migrated lumbar intervertebral disc herniation between 2014 and 2023. The primary endpoint was the ratio of the AES volume between vertebrae adjacent to the herniated disc. The secondary endpoints were patient demographics, disc level, clinical symptoms, disc degeneration, and lumbar instability. AES volume was measured by calculating the area between the posterior vertebral wall concavity and a line connecting the posterior walls on CT images, with the total volume determined as the sum of the slice areas multiplied by the slice width.

Results: A total of 14 patients exhibited rostral HNP migration, while 28 exhibited caudal HNP migration. Rostral HNP migration was associated with a higher prevalence of double-root involvement (p<0.05) and a greater superior/inferior ratio of the AES volume (p<0.01). Multivariate analysis identified the AES volume superior/inferior ratio (odds ratio: 9.551) as a factor significantly associated with the direction of HNP migration.

Conclusions: The HNP tends to migrate toward the direction with a larger AES volume because the herniated material follows the path of least resistance. Clinical presentation of double-root symptoms was strongly indicative of rostral HNP migration.

Introduction: Cervical spinal cord injury (CSCI) without major bone injury is increasing among older adults, particularly in aging societies like Japan. The optimal treatment strategies remain unclear, with conservative therapy often preferred, especially for older patients. However, surgery is frequently necessary due to poor improvement or progression of paralysis during conservative treatment. This study investigated the characteristics and outcomes of older patients with CSCI without major bone injury who transitioned from conservative treatment to surgery.

Methods: This nationwide, retrospective study examined data from patients aged ≥65 years with CSCI without major bone injury. The patients were categorized into 3 groups: conservative treatment, planned surgery, and those who switched from conservative treatment to surgery. The study aimed to identify the risk factors for conservative therapy failure that necessitate surgical intervention and to compare the outcomes between patients who had planned surgery and those who required surgery after conservative management failed.

Results: Among 615 patients, 422 (68.6%) received conservative treatment, 193 (31.4%) had planned surgery, and 116 (18.9%) transitioned from conservative to surgical treatment. Transition to surgery was mainly due to poor improvement or progression of neurological deficits. Significant risk factors for transitioning to surgery included younger age, presence of ossification of the posterior longitudinal ligament, and spinal cord signal changes on magnetic resonance imaging. Comparative analysis showed no significant differences in neurological outcomes between patients who had surgery as planned and those who required surgery after failed conservative treatment.

Conclusions: A significant proportion of older patients with CSCI without major bone injury who were initially managed conservatively eventually required surgery due to insufficient neurological improvement. The outcomes of patients who transitioned to surgery were similar to those who had surgery as initially planned, indicating that careful monitoring of conservative treatment followed by surgery, if necessary, may be an effective approach.

Introduction: The prone transpsoas (PTP) approach is a novel, single-position lumbar fusion technique that enables lateral lumbar interbody fusion (LLIF) entirely in the prone position, allowing simultaneous access to both the anterior and posterior spinal columns. While it offers advantages such as achieving circumferential fusion without repositioning the patient, it also presents challenges, including hemodynamic shifts, pressure-related complications, and technical difficulties in navigating complex anatomical structures. This study describes anatomical shifts relative to the lumbar spine when transitioning from the supine to the prone position.

Methods: This retrospective review included patients who underwent posterior lumbar fusion between 2018 and 2024 and had both preoperative magnetic resonance imaging (MRI) and intraoperative prone computed tomography-guided imaging. Patients with deformity, infection, trauma, prior fusion, or malignancy were excluded. Anteroposterior (AP) and mediolateral (ML) distances (in mm) were measured on axial slices using reference lines aligned to vertebral endplates at each lumbar level. Measurements included AP and ML distances to the abdominal great vessels, psoas major, and intervertebral discs. Dependent samples t-tests and analysis of variance were used to assess anatomical shifts from supine to prone and to compare segmental differences.

Results: Among the 74 patients (47% female), the mean age was 62.7±12.2 years, and the mean body mass index was 29.8±5.8 kg/m². Significant AP translation was observed at L2-L3 and L3-L4 for the inferior vena cava (p<0.001) and aorta (p<0.01), and at L4-L5 for the common iliac arteries (p<0.001) and right iliac vein (p<0.05). Symmetric AP excursion of the psoas major muscle was noted at L2-L3 and L4-L5 in the prone position (p<0.05). No significant differences in mean translation were found across lumbar levels.

Conclusions: Prone positioning induces measurable anterior translation of both the psoas major muscle and great vessels, potentially altering the operative corridor utilized in the PTP approach. These discrepancies between supine MRI and prone intraoperative anatomy emphasize the need to account for positional anatomical changes to minimize neurovascular risk during PTP LLIF.

Introduction: Awareness of the harmful effects of long-term low-dose radiation is increasing. There are few comprehensive reports that accurately evaluate the radiation exposure dose to spinal interventionalists during selective nerve root block (SNRB). The purpose of this study was to evaluate the radiation exposure doses from C-arm fluoroscopy to different body areas of the interventionalist and to assess the effectiveness of lead-equivalent protective gear in reducing radiation exposure during SNRB.

Methods: Seven fresh cadavers were irradiated for 1 and 3 minutes using C-arm fluoroscopy to stimulate the real clinical setting of SNRB. The X-ray source was positioned both under and over the table. Radiation exposure doses were measured using real-time dosimeters. Lead-equivalent protective gear was placed on each body part (crystalline lens, thyroid gland, chest, non-dominant hand, dominant hand, gonads, and foot).

Results: Scatter radiation exposure doses to the upper body of the interventionalist were much higher when the X-ray source was positioned over the table compared to when it was positioned under the table. Use of X-ray protective gear reduced radiation exposure to the interventionalist regardless of the X-ray source position. The direct radiation dose to the hand in the irradiated field was extremely high when the X-ray source was positioned over the table-approximately 85 times higher than when under the table. Notably, hand doses remained extremely high even when the interventionalist wore protective gloves, although X-ray-protective-gear reduced overall radiation exposure.

Conclusions: This is the first report to quantify both scattered and direct radiation doses to each body part, as well as the reduction effect of using X-ray protective gear, in detail using fresh cadavers instead of patients. Spinal interventionalists should preferentially use an under-table X-ray source during SNRB and should consistently wear adequate X-ray-protective gear to minimize occupational radiation exposure.

Introduction: Degenerative cervical spondylolisthesis is associated with aging, neck pain, and myelopathy. While anterior spondylolisthesis (AS) has been extensively studied in relation to cervical sagittal parameters, posterior spondylolisthesis (PS) remains poorly understood despite its potential to cause myelopathy. This study investigates the association between PS and cervical sagittal parameters to elucidate its pathophysiology.

Methods: This retrospective study included 169 patients who underwent cervical spine surgery to treat cervical myelopathy, classified into 3 groups: PS, AS, and a control group without spondylolisthesis. Variables assessed included age, sex, body mass index, smoking history, T1 slope, sagittal vertical axis C2-C7 (SVA C2-C7), C2-C7 angle, C2-C7 range of motion, C1-C2 angle, and cervical disk degeneration (summed Pfirrmann grades). Logistic regression analysis was conducted to identify factors significantly associated with PS, and comparisons were made between the PS and AS groups.

Results: Of the 169 participants, 58 had PS, 22 had AS, and 89 formed the control group. A T1 slope ≥29° was significantly associated with PS (odds ratio: 1.090, p=0.005). PS was more common in younger men with mild disk degeneration, while AS was more frequent in older women with severe disk degeneration. Patients with PS exhibited larger C2-C7 angles and smaller SVA C2-C7 compared to those with AS. A high T1 slope appeared to induce a compensatory increase in the C2-C7 angle, generating posterior shear force that may have contributed to the development of PS.

Conclusions: A T1 slope of ≥29° was associated with PS. Our findings suggest that a compensatory mechanism related to a high T1 slope may play a role in the pathophysiology of PS, providing new insights into its development in cervical spinal disorders.

Introduction: In dropped head syndrome (DHS), the factors contributing to the prognosis due to conservative treatment have been unclear. The purpose of this study was to investigate the effect of spinal malalignment due to pre-existing thoracolumbar vertebral fractures on the improvement rate of conservative treatment of DHS.

Methods: Overall, 90 patients with DHS who visited our hospital and underwent conservative treatment for 6 months were included in the study. Patients were divided into 2 groups, Group F with and Group N without thoracolumbar vertebral fracture, and their improvement rate and spinal parameters were compared and statistically examined.

Results: Group F had a significantly larger sagittal vertical axis (SVA) and pelvic incidence minus lumbar lordosis (PI-LL). Cervicothoracic spine alignment did not differ between Groups F and N. The improvement rate of Group F was significantly lower than that of Group N (Group F: 18.8%, Group N: 54.1%).

Conclusions: DHS with thoracolumbar vertebral fracture has significantly large SVA and PI-LL, which would be a poor prognostic factor of conservative treatment.