Recovery of the Japanese orthopedic association back pain evaluation questionnaire score and walking ability following lumbar spinal stenosis surgery.

PURPOSE: We investigated the recovery of the Japanese orthopedic association back pain evaluation questionnaire (JOABPEQ) scores and 6 min walk distance (6MWD) in patients after surgery for lumbar spinal stenosis and identified the items among 25 questions of JOABPEQ that showed recovery. METHODS: A total of 227 patients (average age 71.5 years; SD: 7.5; 121 men) were included from a single center. The outcome measures were JOABPEQ, visual analog scale (VAS), and 6MWD and obtained preoperatively and at 1, 3, 6, and 12 months postoperatively. Mixed-model repeated measures were used to compare the variables at each time point between the surgery groups. RESULTS: The JOABPEQ, VAS, and 6MWD scores generally improved at 1 month postoperatively compared with those obtained preoperatively, and some parameters further improved at 3 months. However, improvement in the lumbar spine dysfunction item of JOABPEQ was delayed, showing improvement at 3 months postoperatively for decompression surgery (average score: pre, 64.6; 3 months, 78.5) and 6 months postoperatively for fusion surgery (average score: Pre, 64.3; 6 months, 77.1). Responses to the individual JOABPEQ questions generally improved after surgery. No significant changes in lumbar spine dysfunction occurred in the fusion group. CONCLUSION: Our results demonstrated the early postoperative recovery course of JOABPEQ and 6MWD. In the fusion group, significant changes in lumbar spine dysfunction started at 6 months postoperatively. These findings could help medical staff explain postoperative recovery to patients after lumbar spinal stenosis surgery and in their decision making regarding surgery.

Variety of preoperative MRI changes in spinal cord ependymoma of WHO grade II: a case series.

PURPOSE: To report a case series of surgically proven spinal ependymomas of WHO grade II in which there were changes in the preoperative MRI characteristics over time. METHODS: A total of 71 patients with spinal cord ependymoma of WHO grade II underwent surgery. There were ten cases in which surgery was performed at an average of 2.2 years after the tumor was found. Cystic components, syringomyelia, hemorrhage "cap sign," Gd enhancement pattern, characteristic changes in MRI, MIB-1 index, and neurological assessment during the preoperative period were examined. RESULTS: Cases with a huge cyst showed further enlargement of the cyst on the caudal and rostral sides with hemosiderin formation over time and changes in the pattern of Gd enhancement. In contrast, cases without initial cyst did not show cyst formation, and nodular homogeneous lesion remained without changes in Gd enhancement. Regarding neurological status, two cases with cyst enlargement and hemosiderin formation had worsened non-independent gait preoperatively. CONCLUSIONS: MRI in cases of spinal ependymomas of WHO grade II showed characteristics such as hemorrhage and cyst formation that varied over time. In particular, cases with cyst and hemosiderin showed tumor enlargement, including enlargement of lesions on the caudal and rostral sides and enlargement of Gd-enhanced lesions. These characteristics might influence gait ability during preoperative period. We emphasize that early surgery is still the standard of care for cervical intramedullary ependymoma, and our findings in this study should not be interpreted to indicate that such early surgery is not necessary in symptomatic cases. These slides can be retrieved under electronic supplementary material.

Reoperation within 2 years after lumbar interbody fusion: a multicenter study.

PURPOSE: Posterior lumbar interbody fusion (PLIF)/transforaminal lumbar interbody fusion (TLIF) can have complications that require reoperation. The goal of the study was to identify risk factors for reoperation within 2 years after PLIF/TLIF. METHODS: A retrospective analysis of a prospective multicenter database was performed for patients who underwent PLIF/TLIF. A total of 1363 patients (689 males and 674 females) were identified, with an average age of 65.9 years old. Comorbidities, perioperative ASA grade, and operative factors were compared between patients with and without reoperation. Risk factors for reoperation were identified in multivariate logistic analysis. RESULTS: There were 38 reoperations within 2 years after PLIF/TLIF (2.8%). The original surgical procedures were open PLIF (n = 26), open TLIF (n = 10), and minimally invasive surgery (n = 2). Reoperation was due to adjacent segment degeneration (ASD) (n = 10), surgical site infection (SSI) (n = 9), screw misplacement (n = 6), postoperative epidural hematoma (n = 6), pseudoarthrosis (n = 4), and cage protrusion (n = 3). Number of levels fused and dural tear were significantly associated with reoperation. In analysis of complications requiring reoperation, SSI was related to diabetes mellitus and dural tear, and postoperative epidural hematoma was related to fusion of two or more levels, EBL, and operation time. In multivariate logistic regression, fusion of two or more levels (HR 2.19) was significantly associated with reoperation. CONCLUSION: Surgical invasiveness, as reflected by number of fused levels, operation time, EBL and dural tear, was associated with reoperation. Fusion of two or more levels is a strong risk factor for reoperation within 2 years after initial PLIF/TLIF. These slides can be retrieved under Electronic Supplementary Material.

Surgical outcomes of spinal cord and cauda equina ependymoma: Postoperative motor status and recurrence for each WHO grade in a multicenter study.

BACKGROUND: The goals of the study are to analyze postoperative outcomes and recurrence in cases of spinal cord and cauda equina ependymoma in each World Health Organization (WHO) Grade, and to examine the influence of extent of surgical removal on prognosis. Spinal ependymoma has a relatively high frequency among intramedullary spinal cord tumors. The tumor is classified in WHO guidelines as grades I, II, and III, but few studies have examined postoperative prognosis based on these grades. METHODS: The records of 80 patients undergoing surgery for spinal cord and cauda equina ependymoma were examined in a multicenter study using a retrospective database. Neurological motor status, pathological type, extent of resection, and tumor recurrence were evaluated. RESULTS: The histopathological types were grade I in 23 cases (myxopapillary: 21, subependymoma: 2), grade II in 52 cases, and grade III in 5 cases (including all anaplastic cases). Total resection was performed in 60 cases (83%), and eight cases had recurrence, including 2 in WHO grade I, 2 in grade II, and 4 in grade III. The 5-year recurrence-free survival rates were 90%, 91%, and 20% in grades I, II and III, respectively. Adjuvant radiotherapy for the local site was performed in 8 cases, including 3 in grade I and 5 in grade III; however, 4 of the 5 grade III cases (80%) had recurrence after radiotherapy. Among 59 patients with normal ambulation or independence without external assistance (McCormick Grade I or II), 53 (90%) maintained the same mobility after surgery. In cases that underwent total resection, the recurrence rate was significantly lower (p < 0.01). A good preoperative motor status also resulted in significantly better postoperative recovery of motor status (p < 0.05). CONCLUSIONS: Total resection of spinal cord and cauda equina ependymoma leads to postoperative motor recovery and may reduce tumor recurrence. Therefore, early surgery for this tumor is recommended before aggravation of paralysis.

Ultrasonography has a diagnostic value in the assessment of cervical radiculopathy: A prospective pilot study.

OBJECTIVE: This study investigated the diagnostic accuracy of the difference in the cross-sectional areas (CSAs) of affected cervical nerve roots (NRs) for diagnosing cervical radiculopathy (CR). METHODS: In total, 102 CR patients and 219 healthy volunteers were examined with ultrasound. The CSA of the cervical NR at each level was measured on the affected side and the contralateral side in CR patients by blinded ultrasonographic technicians. The difference between the CSAs of CR patients and normal volunteers and the difference in the laterality of CSA at the same affected level (ΔCSA) were calculated for each cervical level. RESULTS: The CSAs of the affected NRs in CR patients were significantly larger than those of the unaffected NRs in CR patients and those of the control group at the C5, C6 and C7 levels (P<0.005). ΔCSA was also significantly larger in the CR group at all levels (P<0.001). A receiver operating characteristic analysis demonstrated that the threshold values were 9.6 mm2 (CSA) for C5NR and 15 mm2 for both C6NR and C7NR. CONCLUSIONS: This study revealed that the CSAs of affected NRs were enlarged and that the laterality of the CSA (ΔCSA) was greater in CR patients than in control patients. KEY POINTS: • Cervical radiculopathy is diagnosed through ultrasonographic measurement of the CSAs. • The CSAs of affected nerve roots were significantly enlarged. • The ΔCSA in the CR group was significantly higher than in the control group. • Diagnostic CSA and ΔCSA thresholds were identified.

Prevalence of C7 level anomalies at the C7 level: an important landmark for cervical nerve ultrasonography.

BACKGROUND: Recently, various examination and intervention techniques using cervical nerve ultrasonography have been developed. The specific shapes of the C7 transverse process and vertebral artery in front of the C7 transverse process have become landmarks. PURPOSE: To determine the prevalence of anomalies and anomalous vertebral artery entrances at the C7 transverse process. MATERIAL AND METHODS: The records of patients who underwent plain or contrast-enhanced neck or cervical spine computed tomography (CT) were reviewed. The examinations were scored for the anomalous presence of anterior tubercles or cervical ribs as well as vertebral artery entrances in the C7 transverse process. The prevalence of anomalies was compared based on patient sex and age. RESULTS: Evaluating the examinations from 2067 patients (1046 men; 1021 women), 1% of patients exhibited an anomalous presence of anterior tubercles, and 0.3% of patients displayed cervical ribs at the C7 transverse process. The prevalence of anomalies process was significantly higher in men aged less than 40 years than in older men (P < 0.001), whereas the prevalence was not higher in women aged less than 40 years than in older women. The prevalence of vertebral artery entry into the C7 transverse foramen was 0.6%. CONCLUSION: Although an anomalous vertebral artery entry into the C7 transverse foramen was rare, the prevalence of an anomaly at the C7 transverse process was higher in men aged less than 40 years. Therefore, we recommend performing CT in younger men before cervical nerve ultrasonographic intervention to avoid misinterpretations at the cervical level.

The prevalence of diffuse idiopathic skeletal hyperostosis in Japan - the first report of measurement by CT and review of the literature.

BACKGROUND: Diffuse idiopathic skeletal hyperostosis (DISH) is prone to be accompanied by a spinal column fracture which is resistant to conservative therapy. This major characteristic of DISH is not recognized adequately by physicians, because the disease's detailed pathological condition has not yet been investigated. Therefore, the purposes of this study were to investigate the prevalence of DISH using computed tomography (CT), and to validate the reliability of CT interpretation. METHODS: Subjects were 558 patients (300 male and 258 female) who underwent both CT of chest to pelvis and x-ray of chest and abdomen from August 2011 to July 2012 at any department other than orthopedic surgery in our institution. The definition of DISH based on x-ray as well as CT was the presence of consecutive fused vertebral bodies according to Resnick's criteria. The prevalence of DISH based on both modalities was calculated in all subjects. For 107 subjects extracted at random, intra- (Cohen kappa) and inter-observer error (Fleiss kappa) were calculated and the levels of fused segments were investigated. RESULTS: Ninety-eight of 558 subjects (17.6%) were diagnosed as DISH by x-ray, and 152 (27.2%) by CT. Among males, 70 of 300 subjects (23.3%) were diagnosed by x-ray, and 116 (38.7%) by CT. Among females, 28 of 258 subjects (10.9%) were diagnosed by x-ray and 36 (14.0%) by CT. The levels of fused segments were presented from thoracic spine to lumbar spine, especially the middle and lower thoracic spine. Cohen kappa of x-ray was 0.587, and that of CT was 0.825. Fleiss kappa of x-ray was 0.552, and that of CT was 0.643. CONCLUSIONS: The prevalence of DISH based on CT was 27.1%, which was higher than that of x-ray. In addition, intra- and inter-observer error by review of CT was less than that of x-ray. CT evaluation would be a better method for precise understanding of the state of DISH.

Large volume inside the cage leading incomplete interbody bone fusion and residual back pain after posterior lumbar interbody fusion.

The purpose of this study is to compare intervertebral bone fusion and clinical outcomes in L4-5 posterior lumbar interbody fusion (PLIF) using the same posterior instrumentation with four combinations of one of three types of interbody cage with one of two bone grafts, iliac and local or only local. In 67 patients who underwent L4-5 PLIF, 19 patients had the Brantigan cage and iliac and local bone graft, 18 with the TELAMON C cage and iliac and local bone graft, 16 with the TELAMON C cage and local bone graft (TL), and 14 with the OIC PEEK cage and local bone graft. Clinical assessments were based on Japanese Orthopaedic Association (JOA) scores and on the visual analogue scale (VAS). The bone fusion assessments were based on radiography and CT scans according to the Brantigan, Steffee, and Fraser criteria. More than 2 years after surgery, these assessments were made. In the results, the fusion outcome for the group receiving TL was significantly less than those for the other three groups. In TL, multivariate logistic regression analysis showed that the inside volume of the cage of ≥2.0 mL was the only significant factor for incomplete fusion. Moreover, the VAS (low back pain) score was significantly higher for TL than for the other three groups. In conclusions, we believe that the large volume inside the cage (≥2.0 mL) with local bone graft may lead incomplete interbody bone fusion and residual postsurgical low back pain after PLIF.

Diagnostic accuracy of multifidus muscle spontaneous activity by needle electromyography for the detection of lumbar foraminal and lateral exit-zone stenosis.

PURPOSE: The medial branch of the posterior ramus of the lumbar spinal nerve is well known to be innervated independently and to end in the multifidus muscle without anastomosis. This prospective cohort study aimed to determine the diagnostic specificity and sensitivity of multifidus muscle denervation (MMD) by needle electromyography (N-EMG) for lumbar foraminal and lateral exit-zone stenosis (LF/LEZS). METHODS: We enrolled 61 consecutive patients experiencing unilateral dysesthesia and/or leg pain in the L4 or L5 regions with suspicious LF/LEZS. The Japanese Orthopedic Association (JOA) score, Visual Analog Scale (VAS) for leg pain, and N-EMG were examined. In this study protocol, all patients received at least 3 months of conservative therapy. Surgery was performed on patients who experienced less than 50% VAS pain relief compared with their initial score after confirming the responsible level by lumbar nerve root block. The specificity of N-EMG was the proportion of patients who improved with conservative therapies (non-surgery) after 3 months. The sensitivity of N-EMG was the proportion of patients who improved with surgical therapies (surgery) after more than 12 months. RESULTS: Twenty-three patients underwent surgery. The initial lower JOA, positive Kemp test and motor weakness were significantly higher in the surgery group. The MMD by N-EMG indicated that 34 of 38 patients were negative in the non-surgery group. In the surgery group, 21 of 23 patients were positive. The diagnostic sensitivity and specificity were 91.3 and 92.1%, respectively. CONCLUSIONS: Needle electromyography is a simple and available additional method for the diagnosis of LF/LEZS.

Surgically treated cases of lumbar spondylolysis and isthmic spondylolisthesis: a multicenter study.

STUDY DESIGN: Prospective database study. OBJECTIVES: To grasp the characteristics of surgically treated cases with lumbar spondylolysis or isthmic spondylolisthesis. SUMMARY OF BACKGROUND DATA: A detailed analysis of surgically treated cases with spondylolysis or isthmic spondylolisthesis has never been reported. An epidemiological study in Japan conducted on 2000 subjects found the incidence of lumbar spondylolysis in the Japanese general population (population-based study) to be 5.9% (males: 7.9%, females: 3.9%). Among 124 vertebrae with spondylolysis, there were 0.8% L2 lesions, 3.2% L3 lesions, 5.6% L4 lesions, and 90.3% L5 lesions, including 5 cases (4.3%) with multiple-level lesions. METHODS: We have been registering surgically treated spine cases in our database since 2000. From this database, we prospectively collected cases with lumbar spondylolysis or isthmic spondylolisthesis that were treated surgically between January 2000 and December 2009. We determined the age at surgery, sex, and vertebral level of spondylolysis. RESULTS: Of the 564 spondylolysis patients treated surgically, 66.8% were male and 33.2% were female. The mean age at surgery was 52.5 years (range, 13-84 y). There were 585 vertebrae with spondylolysis including 21 cases (3.7%) with multiple-level lesions. L5 spondylolysis affected 432 vertebrae and was the most common location (73.8%), followed by 125 L4 lesions (21.4%), 24 L3 lesions (4.1%), and 2 L2 lesions (0.7%). CONCLUSIONS: The percentage of L4 lesions in our study was significantly higher and of L5 lesions was significantly lower than those lesions' percentages in the population-based study. L4 spondylolysis may be more unstable or cause clinical symptoms more frequently leading to more surgical intervention. The percentage of multiple-level spondylolysis was similar between the 2 studies, suggesting these patients respond relatively well to conservative treatment. The male/female ratio was 2:1 in both studies, indicating that males and females require surgery at a similar frequency.

Appropriate timing of surgical intervention for the proximal type of cervical spondylotic amyotrophy.

PURPOSE: The purposes of this study were to evaluate the clinical outcome after surgical treatment of patients with the proximal type of cervical spondylotic amyotrophy (CSA) and to explore the appropriate timing for surgical intervention. MATERIALS AND METHODS: A retrospective review was performed on a consecutive cohort of 41 patients who underwent surgical treatment for the proximal type of CSA between 1995 and 2011 at the Nagoya Spine Group Hospitals. We collected information regarding age, type of muscle atrophy, preoperative and final manual muscle test, duration of symptoms, high-intensity areas on T2-weighted MRI images, low-intensity areas on T1-weighted MRI images, levels of spinal canal stenosis, the compression lesion site, cervical kyphosis and surgical procedures (laminoplasty, anterior spinal fusion and posterior spinal fusion). Univariate analyses and multivariate logistic regression analysis were performed to identify correlates of a poor outcome. To explore the appropriate timing for performing surgery, we analyzed the data using receiver operating characteristic (ROC) analysis. RESULTS: The duration of CSA symptoms was 11.6 months on average. The surgical results were excellent for 25 patients, good for six, fair for nine and poor for one. On multivariate logistic regression analysis, the duration of symptoms was statistically associated with a poor surgical outcome (OR 1.393, p = 0.011). ROC analysis demonstrated that 4.3 months from the onset of CSA symptoms was the appropriate time to undergo surgery. CONCLUSIONS: Our results indicate that we should recommend surgical intervention to patients with the proximal type of CSA within about 4 months after the onset of symptoms if conservative treatment has not been successful.

Vertebral artery variations and osseous anomaly at the C1-2 level diagnosed by 3D CT angiography in normal subjects.

INTRODUCTION: The craniovertebral junction is anatomically complicated. Representative vertebral artery (VA) variations include the persistent first intersegmental artery (FIA), fenestration of the VA above and below C1 (FEN), posterior inferior cerebellar artery (PICA) from C1/2, and high-riding VA (HRVA). The ponticulus posticus (PP) is a well-known osseous anomaly at C1. Although those anomalies are frequent in patients with cervical deformity, the prevalence of these in subjects with normal cervical spines is still unknown. The aim of this study is to investigate the variations and prevalence of vascular and osseous anomalies based on three-dimensional computed tomographic (3D CT) angiography in patients without any cervical diseases, such as rheumatoid arthritis, Klippel-Feil syndrome, or Down syndrome. METHODS: Eligible subjects were patients who underwent 3D CT angiography by the Department of Otorhinolaryngology and Internal Medicine from January 2009 to October 2013 in our institution. The authors defined a HRVA as a C2 pedicle with a maximum diameter of 4 mm or less. RESULTS: Among 480 subjects with a mean age of 63.1 years, 387 patients were eligible. One hundred and eighteen subjects were female, and 269 were male. HRVA was observed in 10.1% of patients (39 out of 387 cases), FIA in 1.8% (7 cases), FEN in 1.3% (5 cases), and PICA in 1.3% (5 cases). PP was observed in 6.2% of patients (24 cases). CONCLUSION: According to past reports, many VA anomalies could be attributed to congenital or acquired conditions (e.g., rheumatoid arthritis). However, VA anomalies appear to exist even in patients without any such cervical diseases.

The surgical treatment method for an adult posttraumatic thoracolumbar kyphosis patient with osteogenesis imperfecta.

Osteogenesis imperfecta (OI) is an inheritable bone disorder characterized by osseous fragility and ligamentous laxity. It is sometimes difficult to obtain bone union in patients with OI. The purpose of this report is to present a rare case of posttraumatic kyphosis due to a L1 burst fracture in a patient with OI, and to discuss how to treat it to achieve an adequate correction and circumferential fusion. The patient was a 29-year-old man with OI (Sillence type-IA) who had sustained an L1 fracture when he dived head first into a river. After 3 months of conservative therapy with a body cast, he showed disability at work because of his persistent low back pain and fatigue in his whole back. He showed no neurological disorder. Diagnostic imaging revealed localized kyphotic deformity at L1. Therefore, lumbar lordosis and thoracic kyphosis worsened. Anterior release and fusion, and posterior fusion were conducted. Three months after surgical treatment, circumferential fusion was obtained. His low back pain and fatigue in the whole back disappeared, and he could resume work without any difficulty. From the bone union standpoint, the surgical strategy for spinal correction in OI patients is still controversial because of the intractableness of bone union and fragility of the bone itself. The authors achieved circumferential union using anterior fusion and posterior fusion, in which wide bone bed is available owing to spared posterior elements of the spinal column.

A case of mediastinal embryonal carcinoma successfully treated by integrative therapy.

Mediastinal embryonal carcinoma is rare, and the life prognosis of this disease is assumed to be relatively short. We encountered a case of mediastinal embryonal carcinoma for which we could perform radical surgical resection. The patient was male, aged 16 years, and acutely aware of back pain. Because the pain increased during the same year, he visited a local doctor, and an expanding neoplastic lesion was detected in the right thoracic wall by computed tomography (CT). Then he was referred to our institution. Magnetic resonance imaging (MRI) showed a dumbbell type tumor (Eden type 3) at the Th7/8 level. Malignant disease was suspected, so the authors planned and performed CT-guided biopsy. The result showed that this tumor pathologically corresponded to malignant peripheral nerve sheath tumor (MPNST). Therefore, chemotherapy was considered the main treatment. After 2 courses of chemotherapy, the tumor size decreased dramatically. The authors thought that radical resection is possible if there is no intrathoracic tumor dissemination as a result of a favorable response to chemotherapy. We thus perfomed surgical resection after we confirmed by a thoracoscopic exploratory thoracotomy that there was no intrathoracic tumor dissemination. Pathological findings were consistent with an embryonal carcinoma. Both the cutting ends of the thoracic wall and the epidural lateral sides of the excised lesion were negative for tumor cells. There is no image finding from the MRI and PET-CT suggesting metastasis or recurrence in the MRI and PET-CT 18 months after surgical resection. Therefore, the long-term vital prognosis can be expected in this patient.

Bone union rate with autologous iliac bone versus local bone graft in posterior lumbar interbody fusion (PLIF): a multicenter study.

PURPOSE: 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. METHODS: 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. RESULTS: 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%. CONCLUSIONS: 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.

Minimal Clinically Important Difference of the 6-Minute Walk Distance in Patients Undergoing Lumbar Spinal Canal Stenosis Surgery: 12 Months Follow-Up.

STUDY DESIGN: Retrospective review of prospectively collected data. OBJECTIVE: We evaluated the responsiveness of the 6-minute walk distance (6MWD) and determined the threshold of the minimal clinically important difference (MCID) in patients who underwent lumbar spinal stenosis (LSS) surgery. SUMMARY OF BACKGROUND DATA: Little evidence exists on the MCID of 6MWD after LSS surgery. The 6MWD is an objective gait assessment that can be measured quickly. MATERIALS AND METHODS: In total, 126 patients (74 men; average age, 72.2 ± 6.5 yr) were included and assessed preoperatively and at 12 months postoperatively. We used the Oswestry Disability Index (ODI), as an anchor to calculate the MCID for the 6MWD and measured internal and external responsiveness of the 6MWD. The external responsiveness was assessed in 2 ways: (1) One based on the anchoring questionnaire and (2) another based on the scale distribution. The anchor-based approach was evaluated using the Spearman rank correlation coefficient and receiver-operating characteristic curve. The distribution-based approach was evaluated using the minimal detectable change. RESULTS: The ODI scores and 6MWD for each anchor significantly improved postoperatively. The change in the 6MWD was significantly correlated with change in the ODI (6 mo, r = -0.45; 12 mo, r = -0.49). The receiver-operating characteristic analysis demonstrated good discriminative properties for the 6MWD using the ODI anchor (6 mo, 0.72; 12 mo, 0.78). The cutoff values for 6MWD were 102.3 and 57.5 at 6 and 12 months, respectively. In the distribution-based approach, the minimal detectable change for the 6MWD was 95.7 m. CONCLUSIONS: We validated both the internal and external responsiveness of the 6MWD using the ODI and estimated the MCID in the 6MWD for patients undergoing LSS surgery. However, there was lower validity for the MCID among those participants with the high walking ability and low disability at baseline.

Rheumatoid vertical and subaxial subluxation can be prevented by atlantoaxial posterior screw fixation.

PURPOSE: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Complications and outcomes of posterior fusion in children with atlantoaxial instability.

INTRODUCTION: Atlantoaxial instability (AAI) is an uncommon disease in children. Surgical treatment of pediatric patients with AAI poses a challenge to spine surgeons because of the patients' immature bone quality, extensive anatomical variability, and smaller osseous structures. In this study, the authors report complications and outcomes after posterior fusion in children with AAI. METHODS: The authors reviewed medical records of patients 13 years old and younger with AAI who underwent posterior fusion in the Nagoya Spine Group hospitals, a multicenter cooperative study group, from January 1995 to December 2007. We identified 11 patients who underwent posterior fusion, and analyzed their clinical outcomes and complications. To determine if vertical growth within the construct continued after posterior fusion, in three patients at 5 or more years following occipito-cervical (O-C) fusion, intervertebral disc heights and vertebral heights between the fused and non-fused levels were compared on the final follow-up. RESULTS: The initial surgeries were C1-C2 fusions in six patients and O-C fusion in five patients. Successful fusion ultimately occurred in all patients, however, the complication rate related to the operations was high (64%). Complications included neurologic deterioration, pedicle fracture with pedicle screw insertion, C1 posterior arch fracture with lateral mass screw insertion, perforation of the skull with a head pin placement, and fusion extension to adjacent vertebrae. Two patients required reoperation. The mean fixed and non-fixed intervertebral disc heights on the final follow-up were 2.6 and 5.3 mm, respectively, showing that the disc height of the fixed level was less than the non-fused level. Each vertebra lengthened similarly between fused and non-fused levels except for C2 which had a lower growth rate than the other vertebrae. CONCLUSIONS: A high complication rate should be anticipated after posterior fusion in children with AAI. Careful consideration should be paid to pediatric patients with AAI treated by screw and/or rod systems. After posterior fusion in pediatric patients, each vertebra continued to grow, in contrast the disc height decreased between fused levels.

Transvertebral anterior key hole foraminotomy without fusion for the cervicothoracic junction.

BACKGROUND: Various surgical procedures have been used to repair disc herniations and osteophytes at the cervicothoracic junction. Among these procedures, transvertebral anterior foraminotomy without fusion is a relatively less invasive, safe and useful method, although the majority of spinal surgeons remain unfamiliar with this method. We describe the surgical procedure for a transvertebral anterior keyhole foraminotomy without fusion at the cervicothoracic junction, and we assess the middle-term clinical and radiological outcomes. METHODS: Of 118 patients undergoing this surgery in our institute between 2007 and 2010, five (4.2 %) had C8 radiculopathy causing C7/T1 disc herniations or osteophytes. We studied five patients who underwent trans-C7 vertebral keyhole foraminotomy without fusion. We retrospectively examined clinical data, pre- and postoperative neurological status. RESULTS: In all cases, surgical decompression was successfully achieved without difficulty when accessing the pathology. No complications related to the surgical procedure were reported. The follow-up period was 12-28 (mean 20) months. In all patients, the visual analogue scale (VAS) due to radicular pain immediately decreased after the operation and did not increase thereafter. The mean VAS decreased from 7.8 (4.5-9.6) to 1.0 (0-2.1). The Cobb angle at C2-T1 in a neutral position improved from -12.6 (-2.8 to -24.7) degrees to -6.9 (4.2 to -25.4). The postoperative C7/T1 disc height decreased from 5.4 to 4.9 mm, indicating minimal loss. CONCLUSIONS: This procedure allows for direct access to the pathology and is less invasive. In this study, we clarified that this technique yields excellent radiological and clinical outcomes.