辻 崇

Retrospective case series. To examine central neuropathic pain after surgical resection of intramedullary spinal cord tumor (IMSCT). Because of the rarity of IMSCT, there is little information about postoperative neuropathic pain after surgical resection. Eighty-five of 105 patients treated surgically for IMSCT at our hospital between 2000 and 2008 completed the Neuropathic Pain Symptom Inventory (NPSI) and the short form (SF)-36 health inventory. The NPSI score was analyzed against the tumor type and the postoperative Japanese Orthopaedic Association (JOA) score for neurological symptoms. The mean NPSI score of the patients was 13.5. The subscore for paresthesia/dysesthesia was significantly higher than the other subscores. Analysis of the NPSI scores by tumor type revealed no significant differences among patients with ependymoma, astrocytoma, and vascular tumors. The postoperative JOA score showed a weak negative correlation with the NPSI score in patients with thoracic spinal cord tumor, and no correlation in those with cervical tumor. In the 11 patients with hemangioblastoma, intense pain was reported at the level of the tumor, although postoperative paralysis was mild. All the postoperative SF-36 subscores of our study patients were significantly lower than the national average, and a significant negative correlation was observed between the SF-36 and the NPSI subscores. Neuropathic pain after surgical resection reduces the QOL of patients with IMSCTs, and pain severity varies with the tumor's location and histological features, the severity of paralysis, and the location of pain relative to the tumor.

The objective of this study was to evaluate 2 years post-surgical loss of three-dimensional correction in adolescent idiopathic scoliosis (AIS) patients using multi-planar reconstruction computed tomography (CT). Twenty-seven AIS patients treated by segmental pedicle screw (PS) constructs were included in this study. Correction in the axial plane was evaluated using the "relative apical vertebral rotation angle" (rAVR), defined as the difference between the axial rotation angles of the upper instrumented vertebra and the apical vertebra on reconstructed axial CT images. The Cobb angle of the main curve and apical vertebral translation was measured to evaluate the coronal correction. Thoracic kyphosis was also measured for the evaluation of sagittal profile. Measurements were performed before surgery, and 1 week and 2 years after surgery. The relationships between the correction losses and skeletal maturity, and variety of spinal constructs were also evaluated. The mean preoperative Cobb angle of the major curve was 59.1A degrees A A +/- A 11.2A degrees before and 13.0A degrees A A +/- A 7.2A degrees immediately after surgery. Two years later, the mean Cobb angle had increased significantly, to 15.5A degrees A A +/- A 7.8A degrees, with a mean correction loss of 2.5A degrees A A +/- A 1.5A degrees (p < 0.001). The mean preoperative rAVR of 28.5A degrees A A +/- A 8.4A degrees was corrected to 15.8A degrees A A +/- A 7.8A degrees after surgery. It had increased significantly to 18.5 +/- A 8.4 by 2 years after surgery, with a mean correction loss of 2.7A degrees A A +/- A 1.0A degrees (p < 0.001). The mean correction losses for both the Cobb angle and rAVR were significantly greater in the skeletally immature patients. The significant correlations were recognized between the correction losses and the proportion of multi-axial screws, and the materials of constructs. Statistically significant loss of correction in the Cobb angle and apical vertebral axial rotation angle (AVR) were recognized 2 years after surgery using PS constructs. The correction losses, especially AVR, were more evident in the skeletally immature patients, and in patients treated with more multi-axial screws and with titanium constructs rather than with stainless constructs.

Background: The purpose of this study was to test the hypothesis that direct vertebral derotation by pedicle screws (PS) causes hypokyphosis of the thoracic spine in adolescent idiopathic scoliosis (AIS) patients, using computer simulation. Methods: Twenty AIS patients with Lenke type 1 or 2 who underwent posterior correction surgeries using PS were included in this study. Simulated corrections of each patient's scoliosis, as determined by the preoperative CT scan data, were performed on segmented 3D models of the whole spine. Two types of simulated extreme correction were performed: 1) complete coronal correction only (C method) and 2) complete coronal correction with complete derotation of vertebral bodies (C + D method). The kyphosis angle (T5-T12) and vertebral rotation angle at the apex were measured before and after the simulated corrections. Results: The mean kyphosis angle after the C + D method was significantly smaller than that after the C method (2.7 +/- 10.0 degrees vs. 15.0 +/- 7.1 degrees, p < 0.01). The mean preoperative apical rotation angle of 15.2 +/- 5.5 degrees was completely corrected after the C + D method (0 degrees) and was unchanged after the C method (17.6 +/- 4.2 degrees). Conclusions: In the 3D simulation study, kyphosis was reduced after complete correction of the coronal and rotational deformity, but it was maintained after the coronal-only correction. These results proved the hypothesis that the vertebral derotation obtained by PS causes hypokyphosis of the thoracic spine.

Study Design. Retrospective case series. Objective. To evaluate the treatment strategies for spinal meningioma. Summary of Background Data. Although previous studies have demonstrated favorable surgical outcomes for spinal meningioma, with a low incidence of tumor recurrence, few have examined long-term surgical outcomes. Methods. The influence of patient age, surgical margin status (Simpson grade), tumor location, and histological subtype on tumor recurrence were examined retrospectively. In addition, the resected dura mater from Simpson grade I cases was examined for invasive tumor cells and compared with the presence or absence of a dural tail sign on magnetic resonance image. Results. Complete resection (Simpson grades I and II) was performed in 62 patients. Among them, the tumor recurrence rate was 9.7%, all in patients who underwent grade II resection for ventral spinal lesions. The mean duration to reoperation in these patients was 12.2 +/- 5.2 years. Of the 6 patients who underwent incomplete resection (Simpson grade III/IV), all required reoperation for tumor recurrence or regrowth, 5 years later on average. Patients younger than 50 years at the initial surgery had a significantly higher recurrence rate than those aged 50 years or older. Histologic examination of 43 dura mater specimens from Simpson grade I-resection patients revealed tumor cell invasion between the inner and outer layers in 15 patients. This invasion was noted in 8 (29%) of 28 patients who were negative for the dural tail sign on magnetic resonance image, and in 7 (47%) of 15 patients who showed a positive dural tail sign. The MIB-1 index reached about 10% for dumbbell-type meningiomas invading the vertebral body; these were associated with repeated recurrence and unfavorable prognosis. Conclusion. Long-term follow-up after surgery for meningiomas indicated that Simpson grade I resection should be selected whenever practicable when treating younger patients or dumbbell-type meningiomas. Tumors recurred at 12 years, on average, in approximately 30% of patients who underwent grade II resection.

To evaluate the morphologic characteristics of the thoracic pedicle with regard to safe free-hand thoracic pedicle screw placement, based on multi-planar reconstruction CT images. Thirty adolescent idiopathic scoliosis (AIS) patients who had undergone posterior corrective surgery for major thoracic curve were included in this study. Reconstructed CT axial images at each thoracic vertebra were used to measure: (1) the shortest distance from an entry point to the ventral cortex of the lamina (critical distance), and (2) the distance from the entry point to the tangent of the spinal canal at the medial wall of the pedicle (safe distance). The critical length was defined as the distance between the critical distance and the safe distance. The distance from the entry point to the medial wall breach site (breach distance) was measured on post-operative CT images. The mean critical distance was 9.3 +/- A 1.1 mm. The critical distance of vertebrae from different levels was relatively constant, between 8.1 and 10.1 mm. The mean safe distance was 15.2 +/- A 1.3 mm. The safe distance of vertebrae from different levels was also relatively constant, between 14.5 and 16 mm. The mean critical length was 5.9 +/- A 1.0 mm. The critical length of vertebrae between T3 and T12 was relatively constant, ranging from 5 to 6.5 mm. The mean breach distance was 12.3 +/- A 1.3 mm and the each breach always recognized between the critical distance and the safe distance. The risk of pedicle medial wall perforation increases as the pedicle probe advances beyond the critical distance of 8-10 mm from the entry point, while it decreases entering into the safe distance at 14.5-16 mm. These parameters were relatively constant even in the most rotated vertebrae at T9 or those with the narrowest pedicle at T7 or T4.

Study Design. Prospective clinical series. Objective. To investigate the sterility of the posterior elements of the spine during posterior correction surgery. Summary of Background Data. Bacterial growth in the operating field is considered one of the causes of surgical-site infection. Methods. A total of 80 consecutive patients (mean age = 19.5 years) who underwent posterior correction surgery for spinal deformities were included in the study. During surgery, specimens for bacterial culture were obtained by swabs from (1) the skin after cleansing using povidone-iodine scrub solution but before draping, (2) laminae immediately after exposure, (3) laminae immediately after screw placement, (4) laminae immediately before wound closure, (5) a small piece of bone obtained from the spinous process immediately after exposure and placed on a sterile dish during surgery as a control, kept covered, and (6) a similar sample as (5), kept uncovered. The culture was conducted on both blood agar and Gifu anaerobic medium agar plates. Results. No patient developed surgical-site infection. The culture was positive in specimen (S) 1 in 25 patients (31.3%), S2 in 20 (25%), S3 in 25 (31.3%), S4 in 26 (32.5%), S5 in 6 (7.5%), and S6 in 7 (8.8%). Bacterial species included Propionibacterium acnes in 15 specimens, Propionibacterium species in 9, and others in 10. Of the 25 patients with a positive culture in S1 and 55 patients without, 22 (88%) and 26 (47.3%), respectively, demonstrated a positive culture in specimens obtained during surgery. Conclusion. The culture was more frequently positive in specimens obtained immediately before wound closure than in those harvested immediately after exposure and isolated from the surgical field. The results suggest that bacterial contamination of the operating field may originate from the skin of the patient during surgery.

Lumbar spinal canal stenosis (LSCS) is one of the most common spinal disorders in the elderly, and ligamentum flavum (LF) hypertrophy is an important cause of LSCS. Matrix metalloproteinase 13 (MMP13) can degrade fibrillar collagens and elastic microfibrils, and is involved in inflammation and fibrosis. The purpose of this study was to compare the expression of MMP13 in the LF from LSCS patients with diabetes mellitus [DM (+)] with that in the LF from patients without DM [DM (-)] and to analyze the relationship among DM, MMP13 expression, and LF hypertrophy. LFs from 11 DM (+) and 24 DM (-) LSCS patients were analyzed in this study. Histology analysis using hematoxylin and eosin and Masson's trichrome stain was performed for each LF. The expression of MMP13 was analyzed by quantitative real-time PCR. The thickness of LF was measured by CT. In the LF from DM (+) LSCS patients, the elastic fibers were more disorganized and had lower volumes than in the LF from DM (-) LSCS patients, while more fibrotic tissue was observed in the LF from DM (+) than from DM (-) LSCS patients. MMP13 expression was significantly higher in the LF from DM (+) LSCS patients (0.46 +/- A 0.61 vs. 0.05 +/- A 0.09, P = 0.002). The LF from the DM (+) LSCS patients was significantly thicker than that from the DM (-) LSCS patients (5.0 +/- A 0.9 vs. 3.1 +/- A 0.8 mm, P < 0.01), and the thickness was correlated with the expression of MMP13 (correlation coefficient = 0.43, P = 0.01, Pearson's correlation test). DM-related MMP13 expression can be one of the factors contributing to fibrosis and hypertrophy of the LF. Further research on the mechanism of this process may lead to new therapies for LF hypertrophy.

Object. The object of this study was to investigate failures after spinal reconstruction following total en bloc spondylectomy (TES), related factors, and sequelae arising from such failures in patients with malignant spinal tumors. Methods. Fifteen patients (12 males and 3 females, with a mean age of 46.5 years) with malignant spinal tumors who underwent TES and survived for more than 1 year were included in this analysis (mean follow-up 41.5 months). Seven patients had primary tumors, including giant cell tumors in 4 patients, chordoma in 2, and Ewing sarcoma in 1. Eight patients had metastatic tumors, including thyroid cancer in 6 and renal cell cancer and malignant fibrous histiocytoma in 1 patient each. Seven patients without prominent paravertebral extension of the tumor were treated using a posterior approach alone, and 8 patients who exhibited prominent anterior or anterolateral extension of the tumors into the thoracic or abdominal cavity were treated using a combined anterior and posterior approach. Spinal reconstruction after tumor resection was performed using a combination of anterior structural support and posterior instrumentation. The relationship between instrumentation failure and clinical and radiographic factors, including age, sex, history of previous surgery, preoperative radiotherapy, tumor histology, tumor level, surgical approach, number of resected vertebrae, rod diameter, number of instrumented vertebrae, and cage subsidence, was investigated. Results. Six patients (40%) with spinal instrumentation failure were identified: rod breakage occurred in 3 patients, and breakage of both the rod and the cage, combined cage breakage and screw back-out, and endplate fracture arising from cage subsidence occurred in 1 patient each. All of these patients experienced acute or chronic back pain, but only 1 patient with a tumor recurrence experienced neurological deterioration upon instrumentation failure. Cage subsidence (>= 5 mm), preoperative irradiation, and the number of instrumented vertebrae (<= 4 vertebrae) were significantly related to late instrumentation failure. Conclusions. Late instrumentation failure was a frequent complication after TES. Although patients with instrumentation failure experienced back pain, the neurological sequelae were not catastrophic. For prevention, meticulous preparation of the graft site and a longer posterior fixation should be considered. (DOI: 10.3171/2011.5.SPINE10813)

Because of the lack of long-term postoperative follow-up studies of idiopathic spinal cord herniation (ISCH), there is little information about the long-term effectiveness and complications of the dural defect enlargement in patients with ISCH. The purpose of this study is to determine the long-term effectiveness of this procedure. Sixteen patients with ISCH were treated surgically by enlargement of the dural defect. The patient's neurological status and surgical outcome were evaluated by the JOA scores for thoracic myelopathy and the recovery rate (mean follow-up period 9.6 years). Correlations between the surgical outcomes and patients' age and duration of disease were assessed retrospectively. The patients were also divided into two groups based on the location of the dural defect: the ventro-lateral (VL) group and the ventral (V) group. The difference in the duration of disease, preoperative JOA score, and the recovery rate were compared between the two groups. There was no recurrence of ISCH after surgery. The mean recovery rate was 42.6%. There was a significant correlation between the patient's age and the recovery rate, and between the duration of disease and the recovery rate. The median recovery rate was significantly lower in the V group than in the VL group. There were no complications related to CSF leakage after surgery. Long-term surgical outcomes of enlargement of the dural defect for ISCH were stable and favorable without recurrences or any complications. This procedure should be considered for patients with ISCH before their neurological deficit worsens, especially for the patients in whom the dural defect is located at the ventral part of the dural canal.

Cavernous hemangioma consists mainly of congenital vascular malformations present before birth and gradually increasing in size with skeletal growth. A small number of patients with cavernous hemangioma develop scoliosis, and surgical treatment for the scoliosis in such cases has not been reported to date. Here we report a 12-year-old male patient with severe progressive scoliosis due to a huge subcutaneous cavernous hemangioma, who underwent posterior correction and fusion surgery. Upon referral to our department, radiographs revealed a scoliosis of 85° at T6-L1 and a kyphosis of 58° at T4-T10. CT and MR images revealed a huge hemangioma extending from the subcutaneous region to the paraspinal muscles and the retroperitoneal space and invading the spinal canal. Posterior correction and fusion surgery using pedicle screws between T2 and L3 were performed. Massive hemorrhage from the hemangioma occurred during the surgery, with intraoperative blood loss reaching 2800 ml. The scoliosis was corrected to 59°, and the kyphosis to 45° after surgery. Seven hours after surgery, the patient suffered from hypovolemic shock and disseminated intravascular coagulation due to postoperative hemorrhage from the hemangioma. The patient developed sensory and conduction aphasia caused by cerebral hypoxia during the shock on the day of the surgery. At present, two years after the surgery, although the patient has completely recovered from the aphasia. This case illustrates that, in correction surgery for scoliosis due to huge subcutaneous cavernous hemangioma, intraoperative and postoperative intensive care for hemodynamics should be performed, since massive hemorrhage can occur during the postoperative period as well as the intraoperative period.© 2011 Ogura et al licensee BioMed Central Ltd.

Background: Shprintzen-Goldberg syndrome (SGS) is characterized by craniosynostosis and marfanoid habitus. The clinical findings of SGS include neurological, cardiovascular, connective tissue, and skeletal abnormalities. Among these skeletal findings, developmental scoliosis is recognized in half of all patients with SGS. However, no earlier reports have described the surgical treatment of scoliosis associated with SGS. Methods: Four patients (2 boys and 2 girls; mean age at the time of surgery, 7.3 + 4.4 y) with SGS who underwent surgical treatment for progressive scoliosis were reviewed. The radiologic findings, operative findings, and perioperative complications were evaluated. Results: The mean preoperative Cobb angle was 102.8 + 16.9 degrees. The curve patterns were a double curve in 2 cases and a triple curve in 2 cases. Local kyphosis at the thoracolumbar area was recognized in all the cases with a mean kyphosis angle of 49 +/- 16 degrees. Growing rod procedures were performed in 2 patients, and posterior correction and fusion were performed in 2 patients. The mean correction rate was 45% in the patients who underwent the growing rod procedures at the time of growing rod placement and 51% in the patients who underwent posterior correction and fusion. Dislodgement of the proximal anchors occurred in 3 of the 4 patients. One patient developed pseudoarthrosis. Two patients developed deep wound infections, and implant removal was necessary in 1 patient. Conclusions: Surgical treatment for scoliosis in patients with SGS was associated with a high incidence of perioperative and postoperative complications including implant dislodgements and deep wound infections attributable to poor bone quality and a thin body habitus, which are characteristic clinical features of this syndrome. Careful preoperative surgical planning and postoperative care are critical for the surgical treatment of scoliosis associated with SGS, especially in infants requiring multiple surgeries.

Study Design. A retrospective case series. Objective. To propose a novel treatment strategy for chronic atlantoaxial rotatory fixation (AARF). Summary of Background Data. Treatment strategy for chronic or recurrent AARF remains controversial. We have previously reported that a deformity of the superior facet of the axis (C2 facet deformity), which is frequently observed in patients with chronic AARFs, is a risk factor for recurrent dislocation. In this article, we report seven consecutive cases of chronic AARF who underwent closed manipulation followed by external halo fixation and maintained good reduction with the remodeling of the C2 facet deformity. Methods. Seven girls with a chronic AARF who sustained torticollis for an average of 4.6 months after the onset were referred to our clinic. Closed manipulation by careful manipulation under general anesthesia followed by external immobilization with a halo vest was performed in all cases. Radiographic findings and clinical courses were retrospectively reviewed with approvals by the institutional review board. Results. Three-dimensional computed tomography images before reduction revealed persistent atlantoaxial subluxation and the C2 facet deformity in the dislocated side in all cases. Follow-up three-dimensional computed tomographic scans demonstrated the remodeling of the C2 facet deformity at an average of 2.8 months after successful reduction of subluxation. Subsequently, the halo vests were removed and gentle neck range of motion exercise was started in all cases. The normal cervical range of motion was obtained 2 weeks after the removal of halo vests in five cases, whereas the range of motion remained limited in two cases. At a mean follow-up of 17.4 months, neither symptoms nor recurrence of subluxation occurred in all cases. Conclusion. Chronic irreducible and recurrent unstable AARF can be managed successfully by careful closed manipulation followed by halo fixation, if the C1 and C2 have not been osseously fused. The remodeling of the C2 facet deformity detected on follow-up CT scans can be a useful radiographic parameter to determine the appropriate period of halo fixation in this new treatment strategy obviating the need for surgical intervention.

Object To reduce intraoperative damage to the posterior supporting structures of the lumbar spine during de compressive surgery for lumbar canal stenosis (LCS) lumbar spinous process-splitting laminectomy (LSPSL or split laminectomy) was developed This prospective randomized controlled study was conducted to clarify whether the split laminectomy decreases acute postoperative wound pain compared with conventional laminectomy Methods Forty-one patients with LCS were enrolled in this study The patients were randomly assigned to either the LSPSL group (22 patients) or the conventional laminectomy group (19 patients) Questionnaires regarding wound pain (intensity depth and duration) and activities of daily living (ADL) were administered at postoperative days (PODs) 3 and 7 Additionally, the authors evaluated the pre and postoperative serum levels of C-reactive protein and creatine phosphokinase, the amount of pain analgesics used during a 3-day postoperative period and the muscle atrophy rate measured on 1-month postsurgical MR images Results Data obtained in patients in the LSPSL group and in 16 patients in the conventional laminectomy group were analyzed The mean visual analog scale for wound pain on POD 7 was significantly lower in the LSPSL group (16 +/- 17 mm vs 34 +/- 31 mm, respectively, p = 0 04) The mean depth of-pain scores on POD 7 were significantly lower in the LSPSL group than in the conventional group (0 9 +/- 0 6 vs 1 7 +/- 0 8, respectively, p = 0 013) On POD 3 the mean serum creatine phosphokinase level was significantly lower in the LSPSL group (126 +/- 93 U/L) than in the other group (207 +/- 150 U/L) (p = 0 02), on POD 7, the mean serum C reactive protein level was significantly lower in the LSPSL group (1 1 +/- 0 6 mg/dl) than in the conventional laminectomy group (1 9 +/- 1 5 mg/dl) (p = 0 04) The number of pain analgesics taken during the 3-day postoperative period was lower in the LSPSL group than in the conventional laminectomy group (1 7 +/- 1 3 tablets vs 2 3 +/- 2 4 tablets respectively p = 0 22) The mean muscle atrophy rate was also significantly lower in the LSPSL group (24% +/- 15% vs 43% +/- 22%, p = 0 004) Conclusions Lumbar spinous process splitting laminectomy for the treatment of LCS reduced acute postoperative wound pain and prevented postoperative muscle atrophy compared with conventional laminectomy possibly because of minimized damage to the paraspinal muscles (DOI 10 3171/2010 9 SPINE09933)

Object. The optimal management of malignant astrocytomas remains controversial, and the prognosis of these lesions has been dismal regardless of the administered treatment. In this study the authors investigated the surgical outcomes of cordotomy in patients with thoracic malignant astrocytomas to determine the effectiveness of this procedure. Methods. Cordotomy was performed in 5 patients with glioblastoma multiforme (GBM) and 2 with anaplastic astrocytoma (AA). A Kaplan-Meier survival analysis was performed, and the associations of the resection level with survival and postoperative complications were retrospectively examined. Results. Cordotomy was performed in a single stage in 2 patients with GBM and in 2 stages in 3 patients with GBM and 2 patients with AA. In the 2 patients with GBM, cordotomy was performed 2 and 3 weeks after a partial tumor resection. In the 2 patients with AA, the initial treatment consisted of partial tumor resection and subtotal resection combined with radiotherapy, and rostral tumor growth and progressive paralysis necessitated cordotomy 2 and 28 months later. One patient with a secondary GBM underwent cordotomy; the GBM developed 1 year after subtotal resection and radiotherapy for a WHO Grade II astrocytoma. Four patients died 4, 5. 24, and 42 months after the initial operation due to CSF dissemination, and 3 patients (2 with GBM and I with AA) remain alive (16, 39, and 71 months). No metastasis to any other organs was noted. Conclusions. One-stage cordotomy should be indicated for patients with thoracic GBM or AA presenting with complete paraplegia preoperatively. In patients with thoracic GBM, even if paralysis is incomplete, cordotomy should be performed before the tumor disseminates through the CSF. Radical resection should be attempted in patients with AA and incomplete paralysis. If the tumor persists, radiotherapy and chemotherapy are indicated, and cordotomy should be reserved for lesions growing progressively after such second-line treatments. (DOI: 10.3171/2010.4.SPINE09901)

Object. The aim in this study was to evaluate the efficacy of the ball tip technique in placing thoracic pedicle screws (TPSs), as compared with the conventional freehand technique, in both a cadaveric study and a clinical study of patients with adolescent idiopathic scoliosis. Although posterior spinal surgery using TPSs has been widely applied, these screws are associated with the potential risk of vascular, pulmonary, or neurological complications. To further enhance the accuracy and safety of TPS placement, the authors developed the ball tip technique. Methods. After creating an appropriate starting point for probe insertion, a specially designed ball tip probe consisting of a ball-shaped tip with a flexible metal shaft is used to make a guide hole into the pedicle. Holding the probe with the fingertips while using an appropriate amount of pressure or by tapping it gently and continuously with a hammer, one can safely insert the ball tip probe into the cancellous channel in the pedicle. In a cadaveric study, 5 spine fellows with similar levels of experience in placing TPSs applied the ball tip or the conventional technique to place screws in 5 cadavers with no spinal deformities. The incidence of misplaced screws was evaluated by dissecting the spines. In a clinical study, 40 patients with adolescent idiopathic scoliosis underwent posterior surgery with TPS placement via the ball tip or conventional technique (20 patients in each treatment group). The accuracy of the TPS placements was evaluated on postoperative axial CT scanning. Results. In the cadaveric study, 100 TPSs were evaluated, and the incidence of misplaced screws was 14% in the ball tip group and 34% in the conventional group (p = 0.0192). In the clinical study, 574 TPSs were evaluated. One hundred seventy-one intrapedicular screws (67%) were recognized in the conventional group and 288 (90%) in the ball tip group (p < 0.01). In the conventional and ball tip groups, the respective numbers of TPSs with a pedicle breach of <= 2 mm were 20 (8%) and 15 (5%), those with a pedicle breach of > 2 mm were 32 (13%) and 9 (3%; p < 0.01), and those located in the costovertebral joints were 32 (13%) and 7 (2%). Conclusions. In both cadaveric and clinical studies the ball tip technique enhanced the accuracy of TPS placement as compared with the conventional freehand technique. Thus, the ball tip technique is useful for the accurate and safe placement of TPSs in deformed spines. (DOI: 10.3171/2010.3.SPINE09497)

Study Design. Retrospective radiographic/imaging study. Objective. To evaluate preoperative and sequential postoperative radiographs following C1-C2 arthrodesis for atlantoaxial subluxation in patients with rheumatoid arthritis (RA) to determine risk factors for the development of subaxial subluxations (SAS). Summary of Background Data. The development of SAS has often been observed after C1-C2 arthrodesis. However, there have been no previous reports on the correlation between radiographic parameters and the incidence of postoperative SAS. Methods. The study group comprised of 58 patients with RA who underwent C1-C2 arthrodesis due to atlantoaxial subluxation. There were 5 men and 53 women with a mean age of 55.8 years. The mean follow-up period was 137 months. Nineteen patients with a postoperative SAS after C1-C2 arthrodesis were classified as the SAS+ group. Other 39 patients without a postoperative SAS were included in the SAS+ group. Clinical outcomes and plain radiographs were reviewed retrospectively and compared between the 2 groups. Results. The difference between pre- and postoperative atlantoaxial (AA) angles in the SAS+ group was significantly greater than those in the SAS+ group (P = 0.039). The C2-C7 angles changed significantly between pre-and postoperative periods in the SAS+ group (P = 0.039), but not in the SAS+ group (P = 0.897). It was suggested that a large AA angle and a small C2-C7 angle observed at the early postoperative period were the risk factors for the development of SAS. We also demonstrated that a high incidence of the C3-C4 SAS resulted from excessive bone fusion at the C2-C3. Conclusion. Excessive correction of AA angle is likely to cause loss of cervical lordosis, resulting in the development of postoperative SAS. In addition, extensive bony union at C2-C3 following C1-C2 arthrodesis frequently leads to the development of extensive SAS at the C3-C4.

Study Design. Case report. Objective. To report 3 cases of malignant tumors in the upper cervical spine that were treated surgically by a combination of posterior tumor resection and stabilization and anterior tumor resection through a mandible-splitting approach after failed ion-beam radiation therapy. Summary of Background Data. Few clinical reports have described in detail the postoperative complications associated with transoral surgical resection of tumors in the upper cervical spine after unsuccessful ion-beam radiation therapy. Methods. Three patients with malignant tumors in the upper cervical spine who had undergone ion-beam radiotherapy and experienced tumor recurrence were treated by a combination of posterior and anterior surgery through a mandible-splitting approach. One patient (patient 1, a 32-year-old man) had a hemangioendothelioma at the C2 and C3 level, whereas the other 2 patients (patient 2, a 66-year-old woman and patient 3, a 65-year-old man) had a chordoma at the C2 and C3 level. Results. The intralesional but macroscopic total resection of the tumors was achieved in all 3 patients. However, serious complications developed after surgery, including deep wound infection, cerebrospinal fluid leakage, and meningitis in patient 1, prolonged swallowing difficulty, subsidence of the strut graft, and recurrence in patient 2, and deep wound infection and discitis causing progressive paralysis in patient 3. All patients underwent salvage surgery, including debridement of the wound in patient 1, posterior reinforcement using instrumentation and posterior tumor resection for the recurrent tumor in patient 2, and anterior debridement of the wound with a pedicle flap using the pectoral major muscle in patient 3 to address these problems. Patients 1 and 3 had no signs of recurrence at the time of a follow-up examination. Conclusion. Severe complications, mainly associated with the disturbance in healing of the retropharyngeal wall, were observed in all 3 patients. A preventive method, such as primary repair of the retropharyngeal wall using muscular/musculocutaneous flaps, should be considered for patients undergoing resection through a transoral approach after ion-beam irradiation.

Object. In this paper, the authors' goal was to elucidate the clinical features and results of decompression surgery for extraforaminal stenosis at the lumbosacral junction. Methods. Twenty-eight patients with severe leg pain caused by extraforaminal stenosis at the lumbosacral junction (18 men and 10 women; mean age 68.2 +/- 8.9 years) were treated by posterior decompression without fusion using a microendoscope in 19 patients and a surgical microscope or loupe in 9 patients. The decompression procedures consisted of partial resection of the sacral ala, the L-5 transverse process, and the L5-S1 facet joint along the L-5 spinal nerve. The following items were investigated: 1) preoperative neurological findings-2) preoperative radiological findings, including plain radiographs, CT scans, selective radiculography of L-5: 3) surgical outcome as evaluated using the Japanese Orthopaedic Association scale for low-back pain (JOA score) and 4) need for revision surgery. Results. All patients presented with neurological deficits compatible with a diagnosis of L-5 radiculopathy such as weakness of the extensor hallucis longus muscle and sensory disturbance in the L-5 area together with neurogenic claudication. On plain radiographs, 21 patients (75%) and 17 patients (60.7%) exhibited lumbar scoliosis (>= 5 degrees) and wedging of the L5-S1 intervertebral space (>= 3 degrees), respectively. The CT scans demonstrated marked osteophyte formation at the posterolateral margin of the L5-S1 vertebral bodies, and a selective L-5 nerve root block was effective in all patients. All patients reported pain relief immediately after Surgery. The mean JOA scores were 11.3 +/- 3.8 before surgery and 24.3 +/- 3.4 at the time of the final follow-up examination the recovery rate was 68.6 +/- 16.5%. The mean estimated blood loss was 66.6 +/- 98.6 ml, and the mean surgical time was 135.3 +/- 46.5 minutes. No significant difference in the recovery rate of the JOA scores or in the surgical time and blood loss was observed between the 2 surgical approaches. Four patients underwent revision posterior interbody fusion for the recurrence of radicular pain as a result of intraforaminal stenosis in 3 patients and insufficient decompression of the extraforaminal area in the remaining patient at an average of 19.5 months after surgery. Conclusions. Extraforaminal stenosis at the lumbosacral junction is a rare but distinct pathological condition causing L-5 radiculopathy. Decompression surgery without fusion using a microendoscope or a surgical microscope/loupe is a feasible and less invasive surgical option for elderly patients with extraforaminal stenosis at the lumbosacral junction. (DOI: 10.3171/2009.7.SPINE09344)

Study Design. A case report. Objectives. To report a case of progressive kyphoscoliosis associated with a tethered cord that was corrected by posterior vertebral column resection after complicated untethering surgery. Summary of Background Data. There have been few clinical reports on posterior vertebral column resection conducted for severe deformity associated with a tethered cord. Methods. A patient with progressive kyphoscoliosis associated with a tethered cord first underwent untethering surgery, resulting in neurologic deterioration. Posterior vertebral column resection was performed to correct the kyphoscoliosis while shortening the spinal column to prevent the spinal cord from stretch injury. Results. Good correction of kyphoscoliosis was obtained without further neurologic deterioration. The Cobb angles of scoliosis was 103 before surgery and 25 after surgery (correction rate; 75.7%), and that of kyphosis was 90 and 36, respectively (correction rate; 60.0%). Conclusion. Correction of progressive kyphoscoliosis associated with a tethered cord can be achieved successfully by posterior vertebral column resection even after complicated untethering surgery.

Study Design. Retrospective case series. Objective. To evaluate our treatment strategy for myxopapillary ependymomas of the cauda equina. Summary of Background Data. Some patients with myxopapillary ependymoma develop cerebrospinal fluid (CSF) dissemination leading to poor prognosis. Because of the rarity of this tumor, there is no consensus on its optimal treatment options and prognosis. Methods. We reviewed 25 cases of myxopapillary ependymomas, treated surgically between 1972 and 2005. The mean postoperative follow-up period was 10.4 years. The effects of surgical margins at surgery and postoperative radiotherapy on tumor recurrence and prognosis were investigated. Results. In 15 patients, total resection achieved (6 cases of en bloc resection without postoperative radiation, and in 9 cases piecemeal resection) was followed by whole brain and spinal cord radiation or local irradiation. Fourteen of these patients survived without tumor recurrence. In 1 case of total resection without radiotherapy, the tumor capsule was violated intraoperatively and local recurrence occurred 2 years after surgery. In 4 patients, the tumors were removed subtotally. Of these, 2 patients who received radiation (24 Gy) only to the whole brain and spinal cord developed recurrence, and 2 who received whole brain and spinal cord radiation ( 24 Gy) supplemented with local radiation (46 Gy) developed no recurrence. The remaining 6 patients received partial resection after local radiation (40-50 Gy) alone, and all 6 died of CSF dissemination. Conclusion. The results of the present study indicate that the surgical margin obtained at the initial surgery and the extent and amount of postoperative radiation can be crucial factors determining the prognosis of patients with myxopapillary ependymoma. Although this tumor is histologically benign, CSF dissemination can occur once tumor capsule is violated, before or during surgery. Therefore, early diagnosis is essential, and a therapeutic strategy including radiotherapy, on the assumption that this tumor is malignant, should be established.

Study Design: Retrospective case series. Objective: To determine the clinical significance and prognosis of idiopathic syringomyelia. Summary of Background Data: With the widespread use of magnetic resonance imaging, cases of syringomyelia are found occasionally. However, the clinical significance and optimum treatment strategy for idiopathic syringomyelia remain unclear, because there are few reports on details of this condition. Methods: The clinical records and magnetic resonance images of 15 patients with idiopathic syringomyelia were reviewed to determine the changes in patient's neurologic status assessed by the Japanese Orthopedic Association scores for cervical myelopathy and the distribution of the syringomyelia on magnetic resonance imaging. Twelve cases were treated conservatively (conservative group) and syringo-subarachnoid shunt was performed in the remaining 3 cases (surgical group). The follow-up period ranged from 7 to 20 years (mean: 10.5 y). Results: The localized type of idiopathic syringomyelia, which extended under 3 vertebras (mean: 2.1 vertebras), was observed in the 12 patients of the conservative group. There were no significant changes in either the size of the syringomyelia or the severity of the neurologic deficits during the follow-up period (mean: 10 y). In contrast, the extended type, which distributed over 4 or more vertebras (mean: 10.2 vertebras), was observed in the 3 patients of the surgical group. Because of severe and progressive neurologic deficits, syringo-subarachnoid shunt was performed and the surgery successfully prevented further neurologic deterioration. The mean Japanese Orthopedic Association score of the surgical group was significantly lower than that of the conservative group, both at the time of the initial examination and at the final follow-up. Conclusions: There are 2 types of idiopathic syringomyelia. One is a "localized'' type, which might represents congenital enlargement of the central canal of the spinal cord, and can be managed conservatively. The other is an "extended'' type, which causes progressive neurologic dysfunction, and should be treated surgically to prevent further neurologic deterioration. Further study should be needed to clarify the mechanism of the extended type of idiopathic syringomyelia.

Study Design. Questionnaire survey on leg cramps for patients with lumbar spinal canal stenosis (LCS). Objective. To evaluate the prevalence of leg cramps in patients with LCS treated surgically and the relationship between leg cramps and the surgical outcomes. Summary of Background Data. Although it has been anecdotally reported that LCS patients have suffered from leg cramps, the true prevalence remains unknown. Methods. One hundred twenty LCS patients who underwent decompression surgery (men 85, women 35, mean age 73.5) and 370 elderly subjects from the general population (men 162, women 208, mean age 75.6) were enrolled in the study. The participants filled in a questionnaire regarding: (all participants) (1) experience of leg cramps, (2) frequency and time of the day of the cramp attacks; (for LCS patients only), (3) changes in cramps before and after surgery, (4) activities of daily living disturbance because of leg cramps, (5) satisfaction with surgery and walking ability, (6) the Roland-Morris Disability Questionnaire, and (7) the Oswestry Disability Index. Results. Eighty-five (70.8%) patients with LCS and 137 (37.2%) of the control population experienced leg cramps (age and sex adjusted odds ratio; 4.6, P < 0.01). Leg cramps occurred once or twice a week in 34.9% of the LCS group and once in several months in 44.5% of the control group, and occurred nocturnally in 73.3% of the LCS patients and in 91.6% of the control group. In LCS patients, leg cramps improved after surgery in 18.2%, remained unchanged in 45.5%, and worsened in 26.1%, and activities of daily living were disturbed in 47.6%. There was no significant difference in satisfaction with surgery, the Oswestry Disability Index, the Roland-Morris Disability Questionnaire scores, or walking ability between the LCS patients with or without leg cramps. Conclusion. LCS patients had significantly more frequent attacks of nocturnal leg cramps than the control population, and leg cramps disturbed the quality of the patients' life, and they rarely improved after decompression surgery. Leg cramps should be recognized as one of the symptoms of LCS, which disturb the patients' quality of life.

Object. This retrospective study was conducted to evaluate the prevalence and clinical consequences of postoperative lamina Closure after open-door laminoplasty and to identify the risk factors. Methods. Eighty-two consecutive patients with cervical myelopathy who underwent open-door laminoplasty without plates or spacers in the open side (Hirabayashi's original method) were included (62 men and 20 women with a mean age of 62 years and a mean follow-up Of 1.8 years). In 67 patients the cause Of cervical myelopathy was spondylotic myelopathy. and in 15 it was Caused by ossification of posterior longitudinal ligament. Radiographic measurements were made of the anteroposterior diameters of the spinal canal and vertebral bodies from C3-6, and the presence of kyphosis were assessed. Lamina closure was defined as >= 10% decrease in the canal-to-body ratio at the final follow-up compared with that immediately after surgery at >= 1 vertebral level. The impact of lamina closure on neck pain, patient satisfaction, Japanese Orthopaedic Association scores. and recovery rates were also evaluated. Results. The mean canal-to-body ratio at C3-6 was 0.69-0.72 preoperatively, 1.25-1.28 immediately after surgery, and 1.18-1.24 at the final follow-up examination. Lamina Closure was observed in 34% of patients and was not associated with sex, age, or Cause of myelopathy, but was significantly associated with the presence of preoperative kyphosis (p = 0.014). Between patients with and without lamina closure, there was no significant difference in preoperative (9.7 +/- 3.1 vs 10.6 +/- 2.5) and postoperative (13.7 +/- 2.4 vs 13.1 +/- 2.7) Japanese Orthopaedic Association scores, recovery rates (53.9 +/- 29.9% vs 44.3 +/- 29.5%. neck pain scores (3.5 +/- 0.7 vs 3.3 +/- 1.0). or patient satisfaction level (4.0 +/- 1.4 vs 4.8 +/- 1.0). Conclusions. Lamina closure at >= 1 vertebral level Occurred in 34% of patients. Although patients with lamina Closure obtained equivalent recovery from myelopathy in a short-term follow-Lip, they tended to be less satisfied with surgery compared with those who did not have Closure. The only significant risk factor identified was the presence of preoperative cervical kyphosis. and preventative methods for lamina closure, therefore, should be considered for patients with preoperative kyphosis. (DOI: 10.3171.SPI.2008.4.08176)

A total of 64 patients with cervical spondylotic myelopathy (CSM) were assessed in this study. Forty-two patients underwent selective expansive open-door laminoplasty (ELAP). Twenty-two patients who underwent conventional C3-7 ELAP served as controls. There were no significant differences in recovery rate of JOA scores, C2-C7 angle or cervical range of motion between two groups. Incidence of axial symptoms and segmental motor paralysis in selective ELAP was significantly lower than those in the C3-7 ELAP. Size of anterior compression mass, postoperative spinal cord positions and decompression conditions were evaluated using preoperative or postoperative MRI in 50 of 64 patients. There was a positive correlation between number of expanded laminae and maximum anterior spaces of spinal cord. Incomplete decompression was developed in three of 37 patients in selective ELAP and in two of 13 patients in C3-7ELAP. Mean size of anterior compression mass at incomplete decompression levels was significantly greater than that at complete decompression levels. Since, there was less posterior movement of the spinal cord in selective ELAP than that in C3-7ELAP, minute concerns about size of anterior compression mass is necessary to decide the number of expanded laminae. Overall, selective ELAP was less invasive and useful in reducing axial symptoms and segmental motor paralysis. This new surgical strategy was effective in improving the surgical outcomes of CSM, and short-term results were satisfactory.

The authors report a case of spontaneous resorption of intradural disc material in a patient with recurrent intradural lumbar disc herniation and review magnetic resonance (MR) imaging and histopathological findings. Intradural lumbar disc herniation is rare, and most patients with this condition require surgical intervention due to severe leg pain and vesicorectal disturbance. In the present case, however, the recurrent intradural herniated mass had completely disappeared by 9 months after onset. Histological examination of intradural herniated disc tissue demonstrated infiltrated macrophages and angiogenesis within the herniated tissue. and Gd-enhanced MR images showed rim enhancement not only at the initial presentation, but also at recurrence. The authors conclude that when rim enhancement is present on Gd-enhanced MR images, there is a possibility of spontaneous resorption even though the herniated mass may be located within the intradural space. Moreover, when radiculopathy is controllable and cauda equina syndrome is absent, conservative therapy can be selected.

Study Design. Experimental study on age-related changes in expression of tissue inhibitor of metalloproteinases-3 (TIMP-3) associated with transition from notochordal nucleus pulposus (NP) to fibrocartilaginous NP in rabbit intervertebral disc (IVD). Objectives. To identify roles of notochordal NP in extracellular matrix (ECM) metabolism of IVD. Summary of Background Data. One of most interesting properties of TIMP-3 is to inhibit aggrecanases in addition to matrix metalloproteinases. Balance of aggrecanase/TIMP-3 is critical to maintain homeostasis of ECM metabolism. Methods. Four-week-old and 160-week-old male Japanese white rabbits were used. Age-related changes in IVDs were evaluated histologically using previously established grading system. Immunohistochemistry of TIMP-3 and semiquantitative reverse transcriptase-polymerase reaction (RT-PCR) of TIMP-3, a disintegrin and metalloproteinases with thrombospondin motifs (ADAMTS) 4, 5, and transforming growth factor-beta 1 (TGF-beta 1), were conducted. Results. Semiquantitative assessment of histologic changes indicated that 4-week-old rabbit was equivalent to fetus to 2-year-old human and 160-week-old rabbit was equivalent to 11- to 30-year-old human, particularly 11- to 16-year-old, which corresponds to transition period from notochordal to fibrocartilaginous NP. Immunohistochemistry revealed that TIMP-3 was positive in 4-week-old rabbit only. Semiquantitative RT-PCR revealed that levels of expressions of TGF-beta 1 and TIMP-3 mRNAs in 4-week-old were significantly higher than those in 160-week-old rabbits. There was no significant difference in expression of ADAMTS4 mRNA. ADAMTS5 mRNA was not detected or extremely low in both groups. Expression of TIMP-3 mRNA in NP was upregulated by TGF-beta 1 but was not affected by IL-1 beta. On the contrary, expression of ADAMTS4 mRNA was not upregulated by TGF-beta 1 but was upregulated by IL-1 beta. Conclusions. Levels of expression of TIMP-3 in notochordal NP were significantly lower in 160-week-old rabbits than those in 4-week-old rabbits. Decrease in expression of TIMP-3, possibly mediated in part by TGF-beta 1, may cause imbalance of ADAMTS4/TIMP-3 ratio at transition period from notochordal to fibrocartilaginous NP.

Background context: Kyphoscoliosis is one of the most frequent complications of osteomalacia, which only rarely results in severe deformity requiring surgery. To the best of our knowledge, there has been only one previous report of a spinal deformity as a complication of osteomalacia that was sufficiently severe so as to require surgical treatment. Purpose: To report here the case of a 27-year-old woman who experienced back pain of gradual onset accompanied by progressive scoliosis resulting in severe dyspnea. Study design: A case report. Methods: She was diagnosed with hypophosphatemic osteomalacia and secondary hyperparathyroidism. She underwent posterior surgical correction and fusion from Th4-L1 using the ISOLA spinal system. Results: At the last follow-up (3 year and 9 months postoperatively), her body balance was good and the dyspnea had disappeared. Plain radiographs demonstrated no loss of correction and also showed no evidence of instrumentation failure. Conclusions: We present a unique instance of a young woman with severe kyphoscoliosis who underwent posterior surgical correction/fusion with spinal instrumentation. © 2006 Elsevier Inc. All rights reserved.

Many investigators have reported that persistent low back pain may occur after posterior surgical intervention, and studies have investigated the histologic and histochemical changes in back muscle after posterior lumbar spine surgery. The purpose of the current study is to compare the pre- and postoperative cross-sectional area of the back musculature among 5 surgical groups including anterior lumbar interbody fusion, which has no direct invasion of the back musculature, using magnetic resonance imaging, and to correlate the clinical results with the degree of atrophy. The cross-sectional area of the back musculature was measured before and after surgery in T2-weighted axial magnetic resonance images using a computer-linked digitizer. The degree of atrophy (atrophy ratio) was calculated as a ratio of the postoperative cross-sectional area to the preoperative cross-sectional area. Clinical results were evaluated using the Japanese Orthopaedic Association's scores for the management of low back pain. Atrophy of the back musculature was confirmed in each group. However, no significant difference was seen in the atrophy ratio between the groups. Back musculature atrophy occurred even in anterior lumbar interbody fusion, which does not involve any direct surgery of the back muscle. A positive correlation was noted between the atrophy ratio and operation time only in posterior surgery, especially in nonfusion surgery. In conclusion, the current study suggests that a shorter operation time may minimize back muscle injury, and shows that factors inducing back musculature atrophy include not only direct invasion of the back muscle via a posterior approach, but also postoperative external fixation.

Monostotic fibrous dysplasia of the spine is extremely rare. We present a 57-year-old mail who complained of persistent low back pain with monostotic Fibrous dysplasia of the lumbar spine. Computed tomography revealed a lytic expansile lesion and marginal sclerosis in the L2 posterior element, although a bone scan did not reveal increased uptake in the lesion. The patient underwent total excision of the tumor via a posterior approach. Two years later, he is asymptomatic with no recurrence of the lesion, as confirmed by imaging.

We present a 24-year-old man and a 3 1 -year-old woman who complained of persistent back pain with osteoid osteoma of the thoracic spine. Computed tomography (CT) revealed a round sclerotic lesion in the posterior element of the thoracic spine ' although their plain radiographs showed no abnormalities except a slight scoliosis. The patients underwent total excision of the tumor via a posterior approach. They are currently asymptomatic with no recurrence of the lesion and have returned to full activity. The thin slice CT is one of the most important diagnostic tools for osteoid osteoma of the spine.

The authors placed titanium mesh cages to achieve posterior atlantoaxial fixation in five patients with atlantoaxial instability caused by rheumatoid arthritis or os odontoideum. A mesh cage packed with autologous cancellous bone was placed between the C-1 posterior arch and the C-2 lamina and was tightly connected with titanium wires. Combined with the use of transarticular screws, this procedure provided very rigid fixation. Solid fusion was achieved in all patients without major complications. The advantages of this method include more stable fixation, better control of the atlantoaxial fixation angle, and reduced donor-site morbidity compared with a conventional atlantoaxial arthrodesis in which an autologous iliac crest graft is used.