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Recently, the number of adult spinal deformity surgeries including sacroiliac joint fixation (SIJF) by using an S2 alar iliac screw or iliac screw has increased to avoid the distal junctional failure. However, we occasionally experienced patients who suffered from hip pain after a long instrumented spinal fusion. We hypothesized that long spinal fusion surgery including SIJF influenced the hip joint as an adjacent joint. The aim of this paper was to evaluate the association between spinal deformity surgery including SIJF and radiographic progression of hip osteoarthritis (OA). This study was retrospective cohort study. In total, 118 patients who underwent spinal fusion surgery at single center from January 2013 to August 2018 were included. We measured joint space width (JSW) at central space of the hip joint. We defined reduction of more than 0.5 mm/year in JSW as hip OA progression. The patients were divided into two groups depending on either a progression of hip osteoarthritis (Group P), or no progression (Group N). The number of patients in Group P and Group N was 47 and 71, respectively. Factor that was statistically significant for hip OA was SIJF (p = 0.0065, odds ratio = 7.1, 95% confidence interval = 1.6–31.6). There were no other significant differences by the multiple logistic regression analysis. This study identified spinal fixation surgery that includes SIJF as a predictor for radiographic progression of hip OA over 12 months. We should pay attention to hip joint lesions after adult spinal deformity surgery, including SIJF.

This study aims to establish normative data for parameters of spino-pelvic and spinal sagittal alignment, gender related differences and age-related changes in asymptomatic subjects. A total of 626 asymptomatic volunteers from Japanese population were enrolled in this study, including 50 subjects at least for each gender and each decade from 3rd to 8th. Full length, free-standing spine radiographs were obtained. Cervical lordosis (CL; C3–7), thoracic kyphosis (TK; T1–12), lumbar lordosis (LL; T12–S1), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS) and sagittal vertical axis (SVA) were measured. The average values (degrees) are 4.1 ± 11.7 for CL, 36.0 ± 10.1 for TK, 49.7 ± 11.2 for LL, 53.7 ± 10.9 for PI, 14.5 ± 8.4 for PT, and 39.4 ± 8.0 for SS. Mean SVA is 3.1 ± 12.6 mm. Advancing age caused an increase in CL, PT and SVA, and a decrease in LL and SS. There was a significant gender difference in CL, TK, LL, PI, PT and SVA. From 7th decade to 8th decade, remarkable decrease of LL & TK and increase of PT were seen. A large increase of SVA was also seen between 60’ and 70’. Standard values of spino-pelvic sagittal alignment were established in each gender and each decade from 20’ to 70’. A remarkable change of spino-pelvic sagittal alignment was seen from 7th decade to 8th decade in asymptomatic subjects.

Nonunion is a major complication of anterior cervical fusion that causes poor outcomes and occasionally requires additional operative intervention. The purpose of this study is to evaluate the accuracy of functional computed tomography (CT) scanning for determining fusion status after anterior cervical fusion by comparing with functional radiographs.The fusion status in 59 patients treated by anterior cervical fusion was assessed by functional radiography and functional CT scanning at 6 and 12 months after surgery. Fusion rates and clinical symptoms were evaluated. Fusion on functional radiography was defined as less than 2 mm of motion between adjacent spinous processes and a particular bony trabeculation on functional CT; fusion was defined as nonexistence of a clear zone or a gas pattern and a particular bone connection on reconstructed sagittal-view images.Functional radiographs demonstrated solid fusion in 83.9% at 6 months and 91.1% at 12 months postoperatively; functional CT showed solid fusion in 55.3 and 78.6%, respectively. The fusion rate detected on functional CT images was significantly lower than that on functional radiographs at each period. At 6 months postoperatively, patients with incomplete union on functional CT were more likely to have neck pain than those who had complete union on functional CT. (46.2 vs 13.3%, P0.05) CONCLUSION: Functional CT can detect nonunion more clearly than functional radiography. At 6 months postoperatively, patients with incomplete union on functional CT images were likely to have more neck pain. Functional CT may allow accurate detection of symptomatic nonunion after anterior cervical fusion.

The pathomechanism of cervical myelopathy due to cervical ossification of posterior longitudinal ligament (C-OPLL) remains unclear. No previous literature has quantified the influence of dynamic factors on cervical myelopathy due to C-OPLL. The purpose was to investigate the influence of dynamic factors on the spinal column in the patients with C-OPLL using CT scan after myelography (MCT).The study included 41 patients with cervical myelopathy due to C-OPLL. An MCT was done during neck flexion and extension, and spinal cord cross-sectional areas (SCCSA) were measured at each disc level between C2/3 and C7/T1. Ossification morphology at each segment was divided into three groups, connection department, coating part, and non-connection department of OPLL group. Dynamic changes of SCCSA in each group of ossification morphology were calculated. The relationship between clinical results and SCCSA at the narrowest level was investigated.MCT showed SCCSA changes during neck extension; 7.4 ± 5.1 mm(2) in the connection department, 5.8 ± 6.0 mm(2) in the coating part, and 6.7 ± 6.4 mm(2) in the non-connection department of OPLL group. There difference was not statistically significant. There was a weak correlation between the JOA score and SCCSA at the narrowest level (R = 0.49). There was no significant correlation between the recovery rate of JOA score and SCCSA at the narrowest level (R = 0.37).Dynamic factors are seen both in cervical myelopathy patients with the continuous type of OPLL and others. Deterioration of myelopathy could be induced by motion effects even in the connection department of OPLL.

Some reported studies have evaluated the dural sac in patients with lumbar spinal stenosis (LSS) by computed tomography (CT) after conventional myelography or magnetic resonance imaging (MRI). But they have been only able to evaluate static factors. No reports have described detailed dynamic changes in the dural sac during flexion and extension observed by multidetector-row computed tomography (MDCT). The aim of this study was to elucidate or demonstrate, in detail, the influence of dynamic factors on the severity of stenosis.One hundred patients with LSS were enrolled in this study. All underwent MDCT in both flexion and extension positions after myelography, in addition to undergoing MRI. The anteroposterior diameter (AP-distance) and cross-sectional area of the dural sac (D-area) were measured at each disc level between L1-2 and L5-S1. The dynamic change in the D-area was defined as the absolute value of the difference between flexion and extension. The rate of dynamic change (dynamic change in D-area/D-area at flexion) in the dural sac at each disc level was also calculated.The average AP-distance in flexion/extension (mm) was 9.2/7.4 at L3-4 and 8.3/7.4 at L4-5. The average D-area in flexion/extension (mm(2)) was 96.3/73.6 at L3-4 and 72.3/61.0 at L4-5. The values were significantly lower in extension than in flexion at all disc levels from L1-2 to L5-S1. AP-distance was narrowest and D-area smallest at L4-5 during extension. The rates of dynamic changes at L2-3 and L3-4 were higher than those at L4-5.MDCT clearly elucidated the dynamic changes in the lumbar dural sac. Before surgery, MDCT after myelography should be used to evaluate the dynamic change during flexion and extension, especially at L2-3, L3-4, and L4-5.

There have been few reports on the risk factors for tracheostomy and the possibility of patients for decannulation. The purpose of this study was to identify factors necessitating tracheostomy after cervical spinal cord injury (SCI) and detect features predictive of successful decannulation in tracheostomy patients.One hundred and sixty four patients with cervical fracture/dislocation were retrospectively reviewed. The patients comprised 142 men and 22 women with a mean age of 44.9 years. The clinical records were reviewed for patients' demographic data, smoking history, level of cervical spine injury, injury patterns, neurological status, evidence of direct thoracic trauma and head injury, tracheostomy placement, and decannulation. Risk factors necessitating tracheostomy and factors predicting decannulation were statistically analysed.Twenty-five patients (15.2%) required tracheostomy. Twenty-one patients were successfully decannulated. Smoking history (relative risk [RR], 3.05; p = 0.03) and complete SCI irrespective of injury level (C1-4 complete SCI: RR, 67.55; p0.001, C5-7 complete SCI: RR, 57.88; p0.001) were significant risk factors necessitating tracheostomy. C1-4 complete SCI was more frequent among those who could not be decannulated. However, even in patients with high cervical complete SCI at the time of injury, patients regaining sufficient movement to shrug their shoulders within 3 weeks after injury could later be decannulated.The risk factors for tracheostomy after complete SCI were a history of smoking and complete paralysis irrespective of the level of injury. High cervical level complete SCI was found to be a risk factor for the failure of decannulation in patients without shoulder shrug within 3 weeks after injury.

The purpose of this study is to compare bone union rate between autologous iliac bone and local bone graft in patients treated by posterior lumbar interbody fusion (PLIF) using carbon cage for single level interbody fusion.The subjects were 106 patients whose course could be observed for at least 2 years. The diagnosis was lumbar spinal canal stenosis in 46 patients, herniated lumbar disk in 12 patients and degenerative spondylolisthesis in 51 patients. Single interbody PLIF was done using iliac bone graft in 53 patients and local bone graft in 56 patients. Existence of pseudo-arthrosis on X-P (AP and lateral view) was investigated during the same follow up period.No significant differences were found in operation time and blood loss. Significant differences were also not observed in fusion grade at any follow up period or in fusion progression between the two groups. Donor site pain continued for more than 3 months in five cases (9%). The final fusion rate was 96.3 versus 98.3%.Almost the same results in fusion were obtained from both the local bone group and the autologous iliac bone group. Fusion progression was almost the same. Complications at donor sites were seen in 19% of the cases. From the above results, it was concluded that local bone graft is as beneficial as autologous iliac bone graft for PLIF at a single level.

Literature has described a risk for subsequent vertical subluxation (VS) and subaxial subluxation (SAS) following atlantoaxial subluxation in rheumatoid patients; however, the interaction of each subluxation and the radiographic findings for atlantoaxial fixation has not been described. The purpose of this study was to evaluate the effects of two different posterior atlantoaxial screw fixation on the development of subluxation in patients with rheumatoid atlantoaxial subluxation.Between 1996 and 2006, rheumatoid patients treated with transarticular fixation and posterior wiring (TA) or C1 lateral mass-C2 pedicle screw fixations (SR) in the Nagoya Spine Group hospitals, a multicenter cooperative study group, were included in this study. VS, SAS, craniocervical sagittal alignment, and range of motion (ROM) at the atlantoaxial adjacent segments were investigated to determine whether posterior atlantoaxial screw fixation is a prophylactic or a risk factor for the development of VS and SAS.The mean follow-up was 7.2 years (4-12). No statistically significant difference was observed among the patients treated with either of the procedure during the follow-up period. Of 34 patients who underwent posterior atlantoaxial screw fixation, SAS was observed in 26.5 % during the follow-up period; however, VS was not observed. Postoperative C2-7 angle, and Oc-C1 and C2-3 ROM were significantly different between patients with and without postoperative SAS. The incidence of SAS was 38.9 % for TA and 12.5 % for SR; statistically significant differences were observed in the postoperative C1-2 and C2-7 angles, and C2-3 ROM.Atlantoaxial posterior screw fixation may be an appropriate prophylactic intervention for VS and SAS if the atlantoaxial joint develops bony fusion following physiological alignment. Compared to TA, SR provided optimal atlantoaxial angle and prevented lower adjacent segment degeneration, thereby reducing SAS.

To clarify the relative frequency of various histopathological primary spinal cord tumors and their features in Japanese people and to compare this data with other reports.Primary spinal cord tumor surgical cases from 2000 to 2009, which were registered in our affiliated hospital database were collected. We examined age at surgery, sex, anatomical location, vertebral level of the tumor, and pathological diagnosis in each case.Of the 678 patients in our study, 377 patients (55.6 %) were males and 301 patients (44.4 %) were females (male/female ratio 1.25). The mean age at surgery was 52.4 years. Of these tumors, 123 cases (18.1 %) were intramedullary, 371 cases (54.7 %) were intradural extramedullary, 28 cases (4.1 %) were epidural, and 155 cases (22.9 %) were dumbbell tumors. The pathological diagnoses included 388 schwannomas (57.2 %), 79 meningiomas (11.6 %), 54 ependymomas (8.0 %), 27 hemangiomas (4.0 %), 23 hemangioblastomas (3.4 %), 23 neurofibromas (3.4 %), and 9 astrocytomas (1.3 %). The male/female ratios for schwannomas, meningiomas, ependymomas, hemangiomas, hemangioblastomas, neurofibromas, malignant lymphomas, and lipomas are 1.4, 0.34, 1.3, 1.5, 2.3, 1.3, 2.7 and 2.3, respectively.This is the first published research in English on the epidemiology of primary spinal cord tumors in Japanese people. Similar to other reports from Asian countries, our data indicates a higher male/female ratio overall for spinal cord tumors, a higher proportion of nerve sheath cell tumors, and a lower proportion of meningiomas and neuroepithelial tumors compared to reports from non-Asian countries. Data in the current study represent the characteristics of primary spinal cord tumors in Asian countries.

Operative decompression is indicated for progressive neurological deterioration in patients with cervical compressive myelopathy (CCM). However, the best timing to ensure clinical recovery has not been determined because of the lack of a suitable method. 10 s step (“step”) test is an easily performed physical test to assess the severity of CCM, particularly for the severity of lower limb dysfunction. The purpose of this study was to analyze the predictive value of preoperative step test results in relation to the results of expansive laminoplasty in patients with CCM. Clinical and imaging data were prospectively collected from 101 patients who underwent cervical expansive laminoplasty for CCM. The Japanese Orthopedic Association (JOA) score and the lower limb function section of the Japanese Orthopedic Association Cervical Myelopathy Evaluation Questionnaire (JOACMEQ-L) were used to evaluate surgical outcomes. Cutoff value was determined by receiver operating characteristic curve analysis to predict clinical recovery after surgery. JOA recovery rate exceeding 50% was defined as an effective clinical result. The treatment was judged to be effective in 30 patients based on the JOACMEQ-L. The cutoff value of the step test was 14.5 in cases of an effective judgment with JOA and JOACMEQ-L. Multivariate analysis showed that preoperative patient age and duration of symptoms were predictive parameters for effectively judging JOA scores. A preoperative step test result of greater than or equal to 14.5 and male gender were significant predictive parameters for an effective judgment with JOACMEQ-L. Preoperative step test results significantly reflected the effective results of JOACMEQ-L and were predictive of improved lower limb function after laminoplasty in patients with CCM. Patients with a score of greater than or equal to 14.5 can experience effective lower limb functional recovery.

The aim of this study is to establish standard MRI values for the cervical spinal canal, dural tube, and spinal cord, to evaluate age-related changes in healthy subjects, and to assess the prevalence of abnormal findings in asymptomatic subjects.The sagittal diameter of the spinal canal and the sagittal diameter and cross-sectional area of the dural tube and spinal cord were measured on MRIs of 1,211 healthy volunteers. These included at least 100 men and 100 women in each decade of life between the third (20s) and eighth (70s). Abnormal findings such as spinal cord compression and signal changes in the spinal cord were recorded.The sagittal diameter of the spinal canal was 11.2 ± 1.4 mm [mean ± standard deviation (SD)]/11.1 ± 1.4 mm (male/female) at the mid-C5 vertebral level, and 9.5 ± 1.8/9.6 ± 1.6 mm at the C5/6 disc level. The cross-sectional area of the spinal cord was 78.1 ± 9.4/74.4 ± 9.4 mm² at the mid-C5 level and 70.6 ± 11.7/68.9 ± 11.3 mm² at the C5/6 disc level. Both the sagittal diameter and the axial area of the dural tube and spinal cord tended to decrease with increasing age. This tendency was more marked at the level of the intervertebral discs than at the level of the vertebral bodies, especially at the C5/6 intervertebral disc level. The spinal cord occupation rate in the dural tube at the C5 vertebral body level averaged 58.3 ± 7.0%. Spinal cord compression was observed in 64 cases (5.3%) and a T2 high-signal change was observed in 28 cases (2.3%).Using MRI data of 1,211 asymptomatic subjects, the standard values for the cervical spinal canal, dural tube, and spinal cord for healthy members of each sex and each decade of life and the age-related changes in these parameters were established. The relatively high prevalence of abnormal MRI findings of the cervical spine in asymptomatic individuals emphasizes the dangers of predicating operative decisions on diagnostic tests without precisely correlating these findings with clinical signs and symptoms.

In the treatment algorithm for cervical spine fracture-dislocations, the recommended approach for treatment if there is a disc fragment in the canal is the anterior approach. The posterior approach is not common because of the disadvantage of potential neurological deterioration during reduction in traumatic cervical herniation patients. However, reports about the frequency of this deterioration and the behavior of disc fragments after reduction are scarce. Forty patients with traumatic disc herniation were observed. They represented 29.2% of 137 consecutive patients with subaxial cervical spine fracture-dislocations. Surgical planning was performed according to our two-stage algorithm. In the first stage, they were treated with posterior open reduction and posterior spine arthrodesis. In the second stage, anterior surgery was added for cases where neurological deterioration attributed to non-reduced disc fragments on postoperative magnetic resonance imaging (MRI). Neurological deterioration after posterior open reduction was not observed. Furthermore, 25% of total cases and 75% of incomplete paralysis cases improved postoperatively by ≥ 1 grade in the American Spinal Injury Association impairment scale. Reduction or reversal of disc herniation was observed in all cases undergoing postoperative MRI. For local sagittal alignment, preoperative 9.4° kyphosis was corrected to 6.9° lordosis postoperatively. The disc height ratio was 72.4% preoperatively and 106.3% postoperatively. The second stage of our plan was not required after the posterior approach in this series. The incidence of neurological deterioration after posterior open reduction was zero, even in cases with traumatic cervical disc herniation. Favorable clinical and radiological outcomes could be obtained by the first stage alone. Although preparations for prompt anterior surgery should always be made to cover any contingency, the need for them is minimal.

Cervical pedicle screw fixation is an effective procedure for stabilising an unstable motion segment; however, it has generally been considered too risky due to the potential for injury to neurovascular structures, such as the spinal cord, nerve roots or vertebral arteries. Since 1995, we have treated 144 unstable cervical injury patients with pedicle screws using a fluoroscopy-assisted pedicle axis view technique. The purpose of this study was to investigate the efficacy of this technique in accurately placing pedicle screws to treat unstable cervical injuries, and the ensuing clinical outcomes and complications. The accuracy of pedicle screw placement was postoperatively examined by axial computed tomography scans and oblique radiographs. Solid posterior bony fusion without secondary dislodgement was accomplished in 96% of all cases. Of the 620 cervical pedicle screws inserted, 57 (9.2%) demonstrated screw exposure (50% of the screw outside the pedicle). There was one case in which a probe penetrated a vertebral artery without further complication and one case with transient radiculopathy. Pre- and postoperative tracheotomy was required in 20 (13.9%) of the 144 patients. However, the tracheotomies were easily performed, because those patients underwent posterior surgery alone without postoperative external fixation. The placement of cervical pedicle screws using a fluoroscopy-assisted pedicle axis view technique provided good clinical results and a few complications for unstable cervical injuries, but a careful surgical procedure was needed to safely insert the screws and more improvement in imaging and navigation system is expected.

To investigation of the outcomes of indirect posterior decompression with corrective fusion for myelopathy associated with thoracic ossification of the longitudinal ligament, and prognostic factors. Conservative treatment for myelopathy associated with thoracic ossification of the longitudinal ligament (OPLL) is mostly ineffective, and treatment is necessary. However, many authors have reported poor surgical outcomes, and no standard surgical procedure has been established. We have been performing indirect spinal cord decompression by posterior laminectomy and simultaneous corrective fusion of the thoracic kyphosis. Twenty patients underwent indirect posterior decompression with corrective fusion, and were included in this study. The follow-up period was minimum 2 years and averaged 2 years and 9 months (2-5 years 6 months). Operative results were examined using JOA scoring system (full marks: 11 points) and Hirabayashi's recovery rate, as excellent (100-75%), good (74-50%), fair (49-25%), unchanged (24-0%) and deteriorated (i.e., decrease in score less than 0%). Cases in which the spinal cord is floating from OPLL on intraoperative ultrasonography were defined as the floating (+) group, and those without floating as the floating (-) group. In addition, we used compound muscle action potentials (CMAP) as intraoperative spinal cord monitoring and the cases were divided into three groups: Group A, no change in potential; Group B, potential decreased, and Group C, potential improved. The mean pre- and postoperative JOA scores were 6.2 and 8.9 points, respectively, and the recovery rate was 56%. The outcome was rated excellent in three, good in eight, fair in six, unchanged in two, and deteriorated in one. The mean preoperative thoracic kyphosis measured 58 degrees , and was corrected to 51 degrees after surgery. On intraoperative ultrasonography, 12 cases were included in the floating (+) and 8 in the floating (-) groups; the recovery rates were 58 and 52%, respectively, showing no significant difference between the recovery rates of the two groups. Regarding intraoperative CMAP, the outcome was excellent in one, good in seven, fair in four, and unchanged in one in Group A; fair in one, unchanged in one, and deteriorated in one in Group B, and excellent in two and good in one in Group C. The recovery rates were 50, 48 and 68.3% in Groups A, B and C, respectively, showing that the postoperative outcome was significantly poorer in Group B. Although indirect posterior decompression with corrective fusion using instruments obtained satisfactory outcomes, not all cases achieved good outcomes using this procedure. We consider that additional application of anterior decompressive fusion is preferable when improvement of symptoms occurs not satisfactory after indirect posterior decompression with corrective fusion using instruments. Intraoperative spinal cord monitoring of CMAP demonstrated that the spinal cord was already impaired during the laminectomy via the posterior approach. Concomitant intraoperative monitoring of CMAP to avoid impairment of the vulnerable spinal cord and corrective posterior spinal fusion with indirect spinal cord decompression is recommendable as a method capable of preventing postoperative neurological aggravation.

Anterior procedures in the cervical spine are feasible in cases having anterior aetiologies such as anterior neural compression and/or severe kyphosis. Halo vests or anterior plates are used concurrently for cases with long segmental fixation. Halo vests are bothersome and anterior plate fixation is not adequately durable. We developed a new anterior pedicle screw (APS) and plate fixation procedure that can be used with fluoroscope-assisted pedicle axis view imaging. Six patients (3 men and 3 women; mean age, 54 years) with anterior multisegmental aetiology were included in this study. Their original diagnoses comprised cervical myelopathy and/or radiculopathy (n = 4), posterior longitudinal ligament ossification (n = 1) and post-traumatic kyphosis (n = 1). All patients underwent anterior decompression and strut grafting with APS and plate fixation. Mean operative time was 192 min and average blood loss was 73 ml. Patients were permitted to ambulate the next day with a cervical collar. Local sagittal alignment was characterised by 3.5° of kyphosis preoperatively, which improved to 6.8° of lordosis postoperatively and 5.2° of lordosis at final follow-up. Postoperative improvement and early bony union were observed in all cases. There was no serious complication except for two cases of dysphagia. Postoperative imaging demonstrated screw exposure in one screw, but no pedicle perforation. APS and plate fixation is useful in selected cases of multisegmental anterior reconstruction of cervical spine. However, the adequate familiarity and experience with both cervical pedicle screw fixation and the imaging technique used for visualising the pedicle during surgery are crucial for this procedure.