Deep learning-based prediction model for postoperative complications of cervical posterior longitudinal ligament ossification.

PURPOSE: Postoperative complication prediction helps surgeons to inform and manage patient expectations. Deep learning, a model that finds patterns in large samples of data, outperform traditional statistical methods in making predictions. This study aimed to create a deep learning-based model (DLM) to predict postoperative complications in patients with cervical ossification of the posterior longitudinal ligament (OPLL). METHODS: This prospective multicenter study was conducted by the 28 institutions, and 478 patients were included in the analysis. Deep learning was used to create two predictive models of the overall postoperative complications and neurological complications, one of the major complications. These models were constructed by learning the patient's preoperative background, clinical symptoms, surgical procedures, and imaging findings. These logistic regression models were also created, and these accuracies were compared with those of the DLM. RESULTS: Overall complications were observed in 127 cases (26.6%). The accuracy of the DLM was 74.6 ± 3.7% for predicting the overall occurrence of complications, which was comparable to that of the logistic regression (74.1%). Neurological complications were observed in 48 cases (10.0%), and the accuracy of the DLM was 91.7 ± 3.5%, which was higher than that of the logistic regression (90.1%). CONCLUSION: A new algorithm using deep learning was able to predict complications after cervical OPLL surgery. This model was well calibrated, with prediction accuracy comparable to that of regression models. The accuracy remained high even for predicting only neurological complications, for which the case number is limited compared to conventional statistical methods.

Protective Attitudes toward Occupational Radiation Exposure among Spine Surgeons in Japan: An Epidemiological Description from the Survey by the Society for Minimally Invasive Spinal Treatment.

Background and Objectives: The global trend toward increased protection of medical personnel from occupational radiation exposure requires efforts to promote protection from radiation on a societal scale. To develop effective educational programs to promote radiation protection, we clarify the actual status and stage of behavioral changes of spine surgeons regarding radiation protection. Materials and Methods: We used a web-based questionnaire to collect information on the actual status of radiation protection and stages of behavioral change according to the transtheoretical model. The survey was administered to all members of the Society for Minimally Invasive Spinal Treatment from 5 October to 5 November 2020. Results: Of 324 members of the Society for Minimally Invasive Spinal Treatment, 229 (70.7%) responded. A total of 217 participants were analyzed, excluding 12 respondents who were not exposed to radiation in daily practice. A trunk lead protector was used by 215 (99%) participants, while 113 (53%) preferred an apron-type protector. Dosimeters, thyroid protector, lead glasses, and lead gloves were used by 108 (50%), 116 (53%), 82 (38%), and 64 (29%) participants, respectively. While 202 (93%) participants avoided continuous irradiation, only 120 (55%) were aware of the source of the radiation when determining their position in the room. Regarding the behavioral change stage of radiation protection, 134 (62%) participants were in the action stage, while 37 (17%) had not even reached the contemplation stage. Conclusions: We found that even among the members of the Society for Minimally Invasive Spinal Treatment, protection of all vulnerable body parts was not fully implemented. Thus, development of educational programs that cover the familiar risks of occupational radiation exposure, basic protection methods in the operating room, and the effects of such protection methods on reducing radiation exposure in actual clinical practice is warranted.

Destructive Spondyloarthropathy due to Congenital Insensitivity to Pain with Anhidrosis: A Case Report of Long-Term Follow-Up.

Congenital insensitivity to pain with anhidrosis (CIPA) is a rare autosomal-recessive hereditary neuropathy causing congenital loss of pain sensation, thermoception, and perspiration. CIPA sometimes causes destructive spondyloarthropathy, the so-called Charcot spine, because of insensitivity to pain stimuli. Herein, we report a case of CIPA with severe spinal destruction treated by multiple spinal reconstructive surgeries and over 15 years of follow-up. A 15-year-old male patient who had been diagnosed with CIPA at the age of 17 months presented to his previous spine clinic with gait disturbance due to muscle weakness in his lower extremities. Imaging studies revealed that collapsed L3 and L4 vertebral bodies involved the spinal canal, and it was treated by L3-L4 instrumented posterior fusion. Fourteen years after surgery, the patient became unable to walk again due to spinal canal stenosis at the proximal fusion segment. An L2-L3 posterior interbody fusion alleviated his gait ability for 2 years; however, he became unable to stand again because of the collapsed fusion segment that caused severe lumbar kyphosis. Subsequently, a two-staged posterior and anterior fusion surgery from the lower thoracic spine to the pelvis was performed, and spinal fusion and neurological recovery were achieved 3 years after surgery. A kyphotic deformity in patients with CIPA-associated Charcot spine could be favorably treated by a long spinal fusion in combination with a reconstruction of an anterior spinal column. This case report provides a significant lesson for a treatment of CIPA-associated Charcot spine.

Prevalence of pre-existing factors causing spinal cord compression: Is there a difference between patients suffering from cervical spinal cord injury with and without bone injury?

BACKGROUND: Recently, the prevalence of elderly patients suffering from cervical spinal cord injury (CSCI) without bone injury has been increasing in various countries. Pre-existing factors causing spinal cord compression, such as ossification of the posterior longitudinal ligament (OPLL), can increase the risk of CSCI without bone injury. However, no study has compared the prevalence of pre-existing factors between CSCI with and without bone injury. This study aimed to compare the prevalence of pre-existing factors between CSCI with and without bone injury. METHODS: In 168 consecutive patients with CSCI, pre-existing factors including OPLL, posterior spur of the vertebral body, developmental stenosis, disc bulge and calcification of yellow ligament (CYL) were evaluated on imaging studies. The prevalence of each type of pre-existing factors was compared between patients with and without bone injury. RESULTS: The prevalence of pre-existing factors in patients without bone injury (86%) was significantly higher than in those with bone injury (20%) (P < 0.001; odds ratio, 23.9). The most common pre-existing factor was OPLL followed by developmental stenosis, posterior spur, disc bulge and CYL in both groups. OPLL, development stenosis and posterior spur were significantly more common in patients without bone injury compared to those with bone injury (P < 0.01). CONCLUSIONS: Prevalence of pre-existing factors, such as OPLL, development stenosis and posterior spur was significantly higher in patients without bone injury than in those with bone injury. Thus, these pre-existing factors might be a potential risk of CSCI without bone injury.

Retrospective comparison of the surgical results for patients with thoracic myelopathy caused by ossification of the posterior longitudinal ligament: Posterior decompression with instrumented spinal fusion versus modified anterior decompression through a posterior approach.

BACKGROUND: In Japan, approximately 75% of patients with thoracic myelopathy caused by ossification of the posterior longitudinal ligament (OPLL) are treated by posterior decompression with instrumented spinal fusion (PDF) because of its efficacy and safety. To achieve more effective decompression of the spinal cord using a posterior approach, anterior decompression through a posterior approach was developed. However, this technique has a high risk of postoperative paralysis. We have added a couple of ingenuities to this procedure (modified Ohtsuka procedure). This study was performed to report the surgical results of our modified Ohtsuka procedure and to compare them with the results of PDF. METHODS: This was a retrospective case series. From 2008 to 2018, we surgically treated 32 patients: 20 patients treated by PDF (PDF group) and 12 patients by our modified Ohtsuka procedure (modified Ohtsuka group) as the initial surgery. All patients were followed up for at least 12 months. The degree of surgical invasion and patients' neurological condition were assessed. RESULTS: The operative duration and intraoperative blood loss indicated no significant differences (PDF vs. Ohtuska: 507 ± 103 vs. 534 ± 99 min, 1022 ± 675 vs. 1160 ± 685 ml, respectively). The preoperative Japanese Orthopaedic Association (JOA) score was 4.5 ± 2.0 in the PDF group and 3.3 ± 1.4 in the modified Ohtsuka group (p < 0.05). However, the latest JOA score and recovery rate were significantly better in the modified Ohtsuka group than in the PDF group (8.9 ± 1.2 vs. 7.4 ± 2.5 and 70.8 ± 17.6% vs. 44.5 ± 40.2%, respectively). Postoperative paralysis did not occur in the modified Ohtsuka group while four patients had it in the PDF group. CONCLUSIONS: The present study clearly indicated the modified Ohtsuka group showed significantly better surgical outcomes than the PDF group with the recovery rate ≥70%.

Reinforcement of Percutaneous Pedicle Screw Fixation with Hydroxyapatite Granules in Patients with Osteoporotic Spine: Biomechanical Performance and Clinical Outcomes.

In percutaneous pedicle screw (PPS) fixation of the osteoporotic spine, rigid screw fixation obtaining strong stabilization is important for achieving successful treatment outcomes. However, in patients with severe osteoporosis, it is difficult to obtain PPS fixation with sufficient stability. PPS fixation has potential disadvantages with respect to maintaining secure stabilization in comparison to conventional pedicle screw fixation. In PPS fixation, bone grafting to achieve posterior spine fusion is generally not applicable and transverse connectors between the rods cannot be used to reinforce the fixation. Various augmentation methods, including additional hooks, sublaminar bands, and hydroxyapatite (HA) sticks, are available for conventional pedicle screw fixation. On the other hand, there has been no established augmentation method for PPS fixation. Recently, we developed a novel augmentation technique for PPS fixation using HA granules. This technique allows the percutaneous insertion of HA granules into the screw hole along the guidewire prior to insertion of the PPS. We have used this augmentation technique for PPS fixation in various spine surgeries in patients with osteoporosis. In our previous studies, biomechanical analyses demonstrated that PPS fixation was significantly enhanced by augmentation with HA granules in the osteoporotic lumbar spine. Furthermore, augmentation with HA granules was considered to decrease the incidence of screw loosening and implant failure following PPS fixation in patients with osteoporotic spine. In this article, we describe the surgical procedures of the augmentation method using HA granules and summarize our data from the biomechanical analysis of augmentation for PPS fixation. We also review the surgical outcomes of PPS fixation with augmentation using HA granules.

Novel augmentation technique of percutaneous pedicle screw fixation using hydroxyapatite granules in the osteoporotic lumbar spine: a cadaveric biomechanical analysis.

PURPOSE: Percutaneous pedicle screw (PPS) fixation has been commonly used for various spine surgeries. Rigid PPS fixation is necessary to decrease the incidence of screw loosening in osteoporotic spine. Recently, we have reported biomechanical advantages of augmentation technique using hydroxyapatite (HA) granules for PPS fixation in synthetic bone. However, its biomechanical performance in augmenting PPS fixation for osteoporotic spine has not been fully elucidated. The aim of the present study is to perform a cadaveric biomechanical analysis of PPS fixation augmented with HA granules. METHODS: Thirty osteoporotic lumbar vertebrae (L1-L5) were obtained from 6 cadavers (3 men and 3 women; age 80 ± 9 years; bone mineral density 73 ± 9 mg/cm3). The maximal pullout strength and maximal insertion torque were compared between the screws inserted into the vertebrae with and without augmentation. In toggle testing, the number of craniocaudal toggle cycles and maximal load required to achieve the 2-mm screw head displacement were also compared. RESULTS: The maximal pullout strength in the screws augmented with HA granules was significantly greater compared to those without augmentation (p < 0.05). The augmentation significantly increased the maximal insertion torque of the screws (p < 0.05). Moreover, the number of toggle cycles and the maximal load required to reach 2 mm of displacement were significantly higher in the augmented screws (p < 0.05). CONCLUSION: The PPS fixation was significantly enhanced by the augmentation with HA granules in the osteoporotic lumbar spine. The PPS fixation augmented with HA granules might decrease the incidence of screw loosening and implant failure in patients with osteoporotic spine.

Association of occupational direct radiation exposure to the hands with longitudinal melanonychia and hand eczema in spine surgeons: a survey by the society for minimally invasive spinal treatment (MIST).

PURPOSE: To investigate the association between occupational direct radiation exposure to the hands and longitudinal melanonychia (LM) and hand eczema in spine surgeons. METHODS: A web-based questionnaire survey of the Society for Minimally Invasive Spinal Treatment (MIST) in Japan was conducted. The proportion of LM and hand eczema in hands with high and low-radiation exposure was compared using Fisher's exact test. The odds ratios (ORs) and their 95% confidence intervals (CIs) for the prevalence of LM and hand eczema in the high-radiation exposure hands were calculated using generalized estimating equations for logistic regression as control for the correlation of observations among the same individuals and possible confounders. RESULTS: Among 324 members of the society, responses were received from 229 members (70.7%). A total of 454 hands from 227 participants were analysed. The prevalence of LM and hand eczema was 43% and 29%, respectively. In a hand-by-hand comparison, more hands had LM in the high-radiation exposure group than the low-radiation exposure group (90 [40%] vs. 39 [17%], respectively, p < 0.001). A similar trend was observed for hand eczema (63 [28%] vs. 33 [15%], respectively, p = 0.001). The adjusted OR for high-radiation exposure hands was 3.18 (95% CI: 2.24-4.52). Consistent results were obtained for hand eczema, with an adjusted OR of 2.26 (95% CI: 1.67-3.06). CONCLUSION: The present study suggests that direct radiation exposure to physician's hands is associated with LM and hand eczema. Those with LM and radially biased hand eczema may have had high direct radiation exposure.

The characteristics of the patients with radiologically severe cervical ossification of the posterior longitudinal ligament of the spine: A CT-based multicenter cross-sectional study.

BACKGROUND: Ossification of the posterior longitudinal ligament of the spine (OPLL) is characterized by heterotopic bone formation in the posterior longitudinal ligament of the spine. We know that the size and distribution of the ossified lesions in patients with OPLL are different in each case. However, the characteristics of the patients with radiologically severe cervical OPLL remain unknown. METHODS: The participants of our study were symptomatic patients with cervical OPLL who were diagnosed by standard radiographs of the cervical spine. Whole-spine CT data and demographic data such as age and sex were obtained from 20 institutions belonging to the Japanese Multicenter Research Organization for Ossification of the Spinal Ligament. According to the number of the levels involved by OPLL, we stratified the patients into two subgroups: severe group (S-group) and non-severe group (NS-group) to delineate the characteristics of radiologically severe patients with cervical OPLL. We also evaluated the most compressed level and the degree of occupying ratio of cervical spinal canal by OPLL at the most compressed level. RESULTS: A total of 234 patients with a mean age of 65 years were recruited. The S-group consisted of 48 patients (21%, 12 females and 36 males) and the NS-group consisted of 92 patients (79%, 22 females and 70 males). The mean age of males in the S-group (68 years old) was significantly higher than that of males in the NS-group (64 years old); however there was no significant difference in the mean age in females between the S-group (69 years old) and the NS-group (66 years old). No significant difference of body mass index, ossification of the nuchal ligament-positivity and presence of diabetes mellitus were found between the S- and the NS-group. CONCLUSIONS: It is likely that the manner of extension of cervical OPLL is different between male and female patients.

Co-existence of ossification of the nuchal ligament is associated with severity of ossification in the whole spine in patients with cervical ossification of the posterior longitudinal ligament -A multi-center CT study.

BACKGROUND: Previous studies have shown that patients with cervical ossification of the posterior longitudinal ligament (OPLL) often have co-existing ossification of the nuchal ligament (ONL). However, no studies have focused on ONL and its relevance to the severity of OPLL or ossification of other spinal ligaments, such as anterior longitudinal ligament (OALL), ligamentum flavum (OLF), and supraspinous/interspinous ligament (OSIL). METHODS: In this multicenter study, we investigated ossification of the spinal ligaments in the whole spine computed tomography (CT) images of 233 cervical OPLL patients. The severity of ossification was evaluated using ossification index for each spinal ligament, calculated as the sum of the level of ossification. We compared the severity of ossification in each spinal ligament between patients with ONL and those without ONL. Furthermore, we investigated how the number of segments, where ONL exists, affects the severity of ossification in each spinal ligament. RESULTS: One hundred thirty patients (55.8%) had co-existing ONL in the cervical OPLL patients included in this study. The ONL (+) group included more male and aged patients. The cervical ossification indexes of OPLL and OALL were higher in ONL (+) patients than in ONL (-) patients. The thoracolumbar ossification indexes of OALL and OSIL were also higher in ONL (+) patients. Logistic regression analysis revealed that age, gender and cervical OA-index were independent factors correlating to the existence of ONL. In the cervical spine, both the ossification indexes of OALL and OPLL increased as the levels of ONL increased. Similarly, in the thoracolumbar spine, both the ossification indexes of OALL and OSIL were increased as the levels of cervical ONL increased. In the multiple regression analysis, cervical OA-index and thoracolumbar OSI-index showed significant correlation with the number of ONL levels. CONCLUSIONS: Co-existence of ONL in cervical OPLL patients was associated with the severity of spinal hyperostosis especially in cervical OPLL, OALL, thoracolumbar OALL and OSIL.

Adjacent segment degeneration after fusion spinal surgery-a systematic review.

PURPOSE: Adjacent segment degeneration (ASDeg) and disease (ASDis) have become major concerns after fusion surgery. However, there is no definitive data or knowledge about the incidence or risk factors. The review discusses the incidence and risk factors and prevention of ASDeg and ASDis in the relevant literature. METHODS: We performed a systematic review of meta-analyses, randomized control trials, and cohort studies published in English to provide evidence-based information about ASDeg and ASDis. RESULTS: According to a meta-analysis, the pooled incidence of ASDeg after lumbar and cervical fusion surgery was 26.6% and 32.8%, respectively. Approximately 1/4-1/3 of ASDeg progressed to ASDis. Risk factors after cervical fusion surgery were young age, pre-existing disc degeneration, short fusion segment, high T1 slope, disruption of adjacent soft tissue, and plate placement close to the adjacent disc. The risk factors of ASDeg and ASDis after lumbar fusion surgery were age, genetic factors, high body mass index, pre-existing adjacent segment degeneration, laminectomy at the adjacent level of fusion, excessive distraction of the fusion level, insufficient lumbar lordosis, multilevel fixation, floating fusion, coronal wedging of L5-S disc, pelvic tilt, and osteoporosis. Motion-preserving surgeries seem to have less risk of ASDeg and ASDis than conventional fusion surgery both in the lumbar and cervical spine. CONCLUSIONS: The existent literature points out variables involved in ASDeg and ASDis. High evidence-level studies should provide more relevant data to guide strategies for avoiding ASDeg and ASDis.

Minimally invasive discectomy for lumbar disc herniation: current concepts, surgical techniques, and outcomes.

PURPOSE: To date, various minimally invasive surgeries for lumbar disc herniation (LDH) have been performed in many countries, including microendoscopic discectomy (MED) and percutaneous endoscopic discectomy (PED). We herein report the surgical indications, current concepts, and techniques of minimally invasive discectomy for LDH, including MED and PED. The postoperative outcomes and risks of complications compared with conventional discectomy are also discussed. METHODS: By reviewing past literatures, the current concepts, surgical techniques, and clinical outcomes were described. RESULTS: Minimally invasive discectomy is generally performed using a transmuscular approach with an endoscopic technique and can reduce muscle and soft tissue damage. The minimal invasiveness can also reduce the severity of postoperative pain and improve patient satisfaction compared with conventional open discectomy. Based on the data of previous systematic reviews and meta-analyses, minimally invasive lumbar discectomy, such as MED and PED, appears to be safe and effective alternatives to open discectomy for patients with symptomatic LDH. These minimally invasive surgeries can provide beneficial effects to shorten the hospital stay and time to return to work. However, minimally invasive discectomy has a demanding learning curve. Only a well-trained surgeon and support team should perform these less invasive procedures. CONCLUSIONS: Clinical evidence supporting the superiority of MED and PED is still limited. Well-designed prospective multicentered randomized controlled trials with large samples are therefore needed in order to draw a convincing conclusion.

Recurrence of ossification of ligamentum flavum at the same intervertebral level in the thoracic spine: a report of two cases and review of the literature.

PURPOSE: Ossification of the ligamentum flavum (OLF) is a possible cause of thoracic myelopathy. We report two rare cases with recurrent thoracic myelopathy caused by OLF markedly re-extended at the same intervertebral level after the primary surgery. METHODS: Both patients had thoracic myelopathy caused by OLF and underwent decompressive laminectomy and resection of the OLF in the primary surgery. However, the neurological conditions gradually deteriorated following recovery after the primary surgery due to the recurrent OLF at the same intervertebral level. RESULTS: These patients were successfully treated by revision surgery via resection of the recurrent OLF and posterior spinal fusion with instrumentation. Two years after the second surgery, the neurological disturbance was resolved satisfactorily, and re-growth of the resected ossified lesion was not observed. CONCLUSIONS: The recurrence of OLF following resection of the ossified lesions is exceedingly rare but should be noted in patients treated surgically for thoracic myelopathy due to OLF.

Recurrent primary osseous hemangiopericytoma in the thoracic spine: a case report and literature review.

PURPOSE: Primary osseous hemangiopericytoma (HPC) of the spine is exceedingly rare. HPC has malignant potential and has the capacity for metastasis and local recurrence. We herein present the first case of recurrent primary osseous HPC in the thoracic spine that was successfully treated by total spondylectomy at three vertebral levels and spinal reconstruction. METHODS: We performed a two-stage operation for recurrent HPC using anterior and posterior approaches at the T5-T7 vertebrae. The preoperative embolization of the tumor was performed to prevent massive intraoperative bleeding. Then, total spondylectomy was performed (T5-T7) to resect the tumor. Anterior spinal reconstruction and posterior instrumentation were performed, with abundant bone autograft and allograft used to achieve sufficient boney fusion following the removal of the tumor. RESULTS: At 2 years after surgery, the patient had made a sufficient recovery from his symptoms. The bone union was complete without tumor recurrence or implant failure. CONCLUSIONS: Total spondylectomy and spinal reconstruction with instrumentation might be useful for performing the safe and adequate excision of recurrent HPC of the spine. However, patients should be closely monitored to detect local recurrence and the malignant degeneration of the tumor after surgery.

Distribution of ossified spinal lesions in patients with severe ossification of the posterior longitudinal ligament and prediction of ossification at each segment based on the cervical OP index classification: a multicenter study (JOSL CT study).

BACKGROUND: In patients with ossification of the posterior longitudinal ligament (OPLL) in the cervical spine, it is well known that the thoracic ossified lesions often coexist with the cervical lesions and can cause severe myelopathy. However, the prevalence of OPLL at each level of the thoracic and lumbar spinal segments is unknown. The aims of this study were to investigate how often OPLL occurs at each level in the thoracolumbar spine in patients with a radiological diagnosis of cervical OPLL and to identify the spinal levels most likely to develop ossification. METHODS: Data were collected from 20 institutions in Japan. Three hundred and twenty-two patients with a diagnosis of cervical OPLL were included. The OPLL index (OP index), defined as the sum of the vertebral body and intervertebral disc levels where OPLL is present, was used to determine disease severity. An OP index ≥20 was defined as severe OPLL. The prevalence of OPLL at each level of the thoracic and lumbar spinal segments was calculated. RESULTS: Women were more likely to have ossified lesions in the thoracolumbar spine than men. Severe OPLL was significantly more common in women than in men (20% vs. 4.5%). For thoracic vertebral OPLL, the most frequently affected was the T1 segment in both men and women, followed by the T1/2 and T3/4 intervertebral levels in men and women, respectively. Ossified lesions were frequently seen at the intervertebral and vertebral levels around the cervicothoracic and thoracolumbar junctions in men with severe OPLL, whereas OPLL was more diffusely distributed in the thoracic spine in women with severe OPLL. CONCLUSION: Thoracolumbar OPLL occurred most often at T1 in men and at T3/4 in women. In severe OPLL cases, although ossified lesions were frequently seen at the intervertebral and vertebral levels around the cervicothoracic and thoracolumbar junctions in men, OPLL could be observed more diffusely in the thoracic spine in women.

Successful Management of Gorham-Stout Disease in the Cervical Spine by Combined Conservative and Surgical Treatments: A Case Report.

Gorham-Stout disease (GSD) is a rare condition characterized by intraosseous proliferation of endothelial-lined vessels and progressive osteolysis. The precise etiology and pathophysiology of the disease remain poorly understood. Current therapeutic options for GSD include chemotherapy, radiotherapy, and surgical resection, but the surgical treatment of GSD is difficult, especially in the spinal lesion. The indication of wide-margined resection was limited because of anatomical features. Herein, we report a case of GSD of the cervical spine in which the lesions were successfully stabilized with combined conservative and surgical treatments. A 15-year-old male patient was admitted because of severe neck pain. The patient presented no neurological deficiency. However, the radiological findings revealed osteolytic lesions on the laminae and vertebrae between C1 to C5. An open biopsy confirmed an irregular, thin-walled vessel formation in the bone trabeculae, which was diagnosed as GSD. Conservative treatment was initiated with chemotherapy and radiotherapy. After one and a half year, the osteolytic condition had regressed. Spinal fusion surgery was then performed from C2 to C5 to prevent for progression of the cervical kyphotic changes, and spinal fusion was confirmed 7 months after the surgery. The patient showed no recurrence of GSD in the 5-year follow-up period after surgery. We were able to provide successful treatment by giving priority to the combined conservative treatments. If a patient has no severe deformity or progressive neurologic deficits, it might be better to prioritize conservative treatments and to perform the surgery after the osteolytic changes have stopped.

Prevalence and distribution of ossification of the supra/interspinous ligaments in symptomatic patients with cervical ossification of the posterior longitudinal ligament of the spine: a CT-based multicenter cross-sectional study.

BACKGROUND: Supra/interspinous ligaments connect adjacent spinous processes and act as a stabilizer of the spine. As with other spinal ligaments, it can become ossified. However, few report have discussed ossification supra/interspinous ligaments (OSIL), so its epidemiology remains unknown. We therefore aimed to investigate the prevalence and distribution of OSIL in symptomatic patients with cervical ossification of the posterior longitudinal ligament (OPLL). METHODS: The participants of our study were symptomatic patients with cervical OPLL who were diagnosed by standard radiographs of the cervical spine. The whole spine CT data as well as clinical parameters such as age and sex were obtained from 20 institutions belong to the Japanese Multicenter Research Organization for Ossification of the Spinal Ligament (JOSL). The prevalence and distribution of OSIL and the association between OSIL and clinical parameters were reviewed. The sum of the levels involved by OPLL (OP-index) and OSIL (OSI-index) as well as the prevalence of ossification of the nuchal ligament (ONL) were also investigated. RESULTS: A total of 234 patients with a mean age of 65 years was recruited. The CT-based evidence of OSIL was noted in 68 (54 males and 14 females) patients (29%). The distribution of OSIL showed a significant thoracic preponderance. In OSIL-positive patients, single-level involvement was noted in 19 cases (28%), whereas 49 cases (72%) presented multi-level involvement. We found a significant positive correlation between the OP-index grade and OSI-index. ONL was noted at a significantly higher rate in OSIL-positive patients compared to negative patients. CONCLUSIONS: The prevalence of OSIL in symptomatic patients with cervical OPLL was 29%. The distribution of OSIL showed a significant thoracic preponderance.

Increasing Incidence of Degenerative Spinal Diseases in Japan during 25 Years: The Registration System of Spinal Surgery in Tohoku University Spine Society.

Spinal disorders affect mainly older people and cause pain, paralysis and/or deformities of the trunk and/or extremities, which could eventually disturb locomotive functions. For ensuring safe and high-quality treatment of spinal disorders, in 1987, the Tohoku University Spine Society (TUSS) was established by orthopedic departments in Tohoku University School of Medicine and its affiliated hospitals in and around Miyagi Prefecture. All spine surgeries have been enrolled in the TUSS Spine Registry since 1988. Using the data from this registration system between 1988 and 2012, we demonstrate here the longitudinal changes in surgical trends for spinal disorders in Japan that has rushed into the most advanced "aging society" in the world. In total, data on 56,744 surgeries were retrieved. The number of spinal surgeries has annually increased approximately 4-fold. There was a particular increase among patients aged ≥ 70 years and those aged ≥ 80 years, with a 20- to 90-fold increase. Nearly 90% of the spinal operations were performed for degenerative disorders, with their number increasing approximately 5-fold from 705 to 3,448. The most common disease for surgery was lumbar spinal stenosis (LSS) (35.9%), followed by lumbar disc herniation (27.7%) and cervical myelopathy (19.8%). In 2012, approximately half of the patients with LSS and cervical myelopathy were ≥ 70 years of age. In conclusion, the number of spinal operations markedly increased during the 25-year period, particularly among older patients. As Japan has a notably aged population, the present study could provide a near-future model for countries with aging population.