Laterality of lumbar disc herniation.

BACKGROUND: Lumbar disc herniation (LDH) is most common in men aged 20-40 at the L4/5 level; however, left-right differences have not been reported. Improving our understanding of left- and right-side LDH may facilitate the estimation of mechanical load on intervertebral discs. Here, we assessed left-right differences in LDH via a retrospective analysis of LDH cases. METHODS: Among 10,972 surgical cases of LDH identified in the Nagoya Spine Group database, 2899 in which right- and left-LDH sides were observable in a single vertebral segment were identified (mean age 46.3 ± 16.6 years, 2028 males). The following characteristics of patients with right- and left-LDH were compared: age, LDH level, surgical technique, operative time, blood loss, length of hospital stay, preoperative Japan Orthopaedic Association (JOA) score, and JOA recovery rate. RESULTS: LDH occurred on the right and left sides in 1358 and 1541 patients, respectively, with patients with right-side LDH significantly older than those with left (47.9 ± 16.6 versus 45.0 ± 16.5, respectively; p < 0.001). No between-group differences in sex, age, LDH level, surgical technique, operative time, blood loss, length of hospital stay, preoperative JOA score, or JOA recovery rate were observed. The occurrence of right-side LDH increased with age, occurring in 42.7%, 45.1%, 49.9%, and 54.7% of patients aged 10-29, 30-49, 50-69, and 70-89 years, respectively. CONCLUSION: Left-side LDH was observed more frequently than right; however, right-side LDH incidence increased with age. No significant between-group differences regarding symptoms, treatments, or outcomes were observed.

Trends in the numbers of spine surgeries and spine surgeons over the past 15 years.

The purpose of this study is to examine trends in spine surgeries at ten facilities over 15 years, and to analyze relationships with the number of spine surgeons at these facilities. The subjects were patients who underwent spine surgery at the ten facilities from 2003 to 2017. Data were collected every year via a questionnaire designed to obtain clinicopathological and surgical information. There were 37,601 spine surgeries (60.2% male) recorded in the registry at 9 facilities in the Nagoya Spine Group (NSG) between 2003 and 2017, with an increase in the annual number of surgeries by 2.4 times over 15 years. On the other hand, the number of spine surgeons has increased by just under 1.5 times. Instrumentation surgeries increased from 959 in 2003 to 2,276 in 2017 (2.3 times). There was a particularly marked increase in surgeries for spinal degenerative disease from 1,075 in 2003 to 2,821 in 2017 (2.6 times). The number of surgeries performed per surgeon increased from 61.4 in 2003 to 102.8 in 2017, while the average number of spine surgeons per hospital increased from 2.6 in 2003 to 3.7 in 2017. In conclusion, with heavier burden on spine surgeons and the major changes in the spine surgery environment, training and increasing surgeons with advanced expertise and skills will become increasingly important.

A Young Boy with Neck Pain.

CASE PRESENTATION: A five-year-old boy presented to our emergency department with severe posterior neck pain that was exacerbated upon neck movement. Cervical spine radiography revealed calcification in the cervical intervertebral disk 3-4. DISCUSSION: Pediatric idiopathic intervertebral disk calcification is a benign, rare condition that might be complicated by associated severe neurological symptoms. In this case, the symptoms gradually subsided with conservative management alone.

Clinical features and prognostic factors in spinal meningioma surgery from a multicenter study.

Meningiomas are benign tumors that are treated surgically. Local recurrence is likely if the dura is preserved, and en bloc tumor and dura resection (Simpson grade I) is recommended. In some cases the dura is cauterized and preserved after tumor resection (Simpson grade II). The purpose of this study was performed to analyze clinical features and prognostic factors associated with spinal meningioma, and to identify the most effective surgical treatment. The subjects were 116 patients (22 males, 94 females) with spinal meningioma who underwent surgery at seven NSG centers between 1998 and 2018. Clinical data were collected from the NSG database. Pre- and postoperative neurological status was defined using the modified McCormick scale. The patients had a mean age of 61.2 ± 14.8 years (range 19-91 years) and mean symptom duration of 11.3 ± 14.7 months (range 1-93 months). Complete resection was achieved in 108 cases (94%), including 29 Simpson grade I and 79 Simpson grade II resections. The mean follow-up period was 84.8 ± 52.7 months. At the last follow-up, neurological function had improved in 73 patients (63%), was stable in 34 (29%), and had worsened in 9 (8%). Eight patients had recurrence, and recurrence rates did not differ significantly between Simpson grades I and II in initial surgery. Kaplan-Meier analysis of recurrence-free survival showed that Simpson grade III or IV, male, and dural tail sign were significant factors associated with recurrence (P < 0.05). In conclusion, Simpson I resection is anatomically favorable for spinal meningiomas. Younger male patients with a dural tail and a high-grade tumor require close follow-up. The tumor location and feasibility of surgery can affect the surgical morbidity in Simpson I or II resection. All patients should be carefully monitored for long-term outcomes, and we recommend lifelong surveillance after surgery.

Risk factors of non-union in Anderson-D'Alonzo type III odontoid fractures with conservative treatment.

OBJECTIVE: The purpose of this study was retrospectively to analyze the risk factors for non-union in Anderson-D'Alonzo type III odontoid fractures with conservative treatment. METHODS: 25 patients with type III fractures were analyzed. Coronal and sagittal tilt as well as sagittal and lateral mass gaps were measured by using computed tomography. RESULTS: The non-union group had significantly higher age, greater coronal tilt and lateral mass gap. Especially, the lateral mass gap was >2 mm in all cases with non-union. CONCLUSIONS: Higher age, coronal tilt, and lateral mass gap were significant risk factors for non-union.

Trends in Reoperation for Surgical Site Infection After Spinal Surgery With Instrumentation in a Multicenter Study.

STUDY DESIGN: A multicenter retrospective analysis of a prospectively maintained database. OBJECTIVE: To examine the characteristics of reoperation for surgical site infection (SSI) after spinal instrumentation surgery, including the efficacy of treatment for SSI and instrumentation retention. SUMMARY OF BACKGROUND DATA: Aging of the population and advances in surgical techniques have increased the demand for spinal surgery in elderly patients. Treatment of SSI after this surgery has the main goals of eliminating infection and retaining instrumentation. METHODS: The subjects were 16,707 patients who underwent spine surgery with instrumentation in 11 hospitals affiliated with the Nagoya Spine Group from 2004 to 2015. Details of those requiring reoperations for SSI were obtained from surgical records at each hospital. RESULTS: There were significant increases in the mean age at the time of surgery (54.6-63.7 years) and the number of instrumentation surgeries (726-1977) from 2004 to 2015. The incidence of reoperation for SSI varied from 0.9% to 1.8%, with a decreasing trend over time. Reoperation for SSI was performed in 206 cases (115 men, 91 women; mean age 63.2 years). The average number of reoperations (1.4 vs. 2.3, P < 0.05), time from SSI to first reoperation (4.3 vs. 9.5 days, P < 0.05), and the methicillin-resistant Staphylococcus identification rate (20% vs. 37%, P < 0.01) were all significantly lower in cases with instrumentation retention (n = 145) compared to those with instrumentation removal (n = 61). CONCLUSION: There were marked trends of aging of patients and an increase in operations over the study period; however, the incidences of reoperation and instrumentation removal due to SSI significantly decreased over the same period. Rapid debridement after SSI diagnosis may have contributed to instrumentation retention. These results can serve as a guide for developing strategies for SSI treatment and for improved planning of spine surgery in an aging society. LEVEL OF EVIDENCE: 3.

Prognostic Factors in the New Katagiri Scoring System After Palliative Surgery for Spinal Metastasis.

STUDY DESIGN: Retrospective study. OBJECTIVE: The purpose of the study was to examine survival after surgery for a metastatic spinal tumor using prognostic factors in the new Katagiri score. SUMMARY OF BACKGROUND DATA: Surgery for spinal metastasis can improve quality of life and facilitate treatment of the primary cancer. However, choice of therapy requires identification of prognostic factors for survival, and these may change over time due to treatment advances. The new Katagiri score for the prognosis of skeletal metastasis includes classification of the primary tumor site and the effects of chemotherapy and hormonal therapy. METHODS: The subjects were 201 patients (127 males, 74 females) who underwent surgery for spinal metastases at six facilities in the Nagoya Spine Group. Age at surgery, gender, follow-up, metastatic spine level, primary cancer, new Katagiri score (including primary site, visceral metastasis, laboratory data, performance status (PS), and chemotherapy) and survival were obtained from a prospectively maintained database. RESULTS: Posterior decompression (n = 29) and posterior decompression and fixation with instrumentation (n = 182) were performed at a mean age of 65.9 (range, 16-85) years. Metastasis was present in the cervical (n = 19, 10%), thoracic (n = 155, 77%), and lumbar (n = 26, 13%) spine, and sacrum (n = 1, 1%). In multivariate analysis, moderate growth (HR 2.95, 95% CI, 1.27-7.89, P < 0.01) and rapid growth (HR 4.71, 95% CI, 2.78-12.31, P < 0.01) at the primary site; nodular metastasis (HR 1.53, 95% CI, 1.07-3.85, P < 0.01) and disseminated metastasis (HR 2.94, 95% CI, 1.33-5.42, P < 0.01); and critical laboratory data (HR 3.15, 95% CI, 2.06-8.36, P < 0.01), and poor PS (HR 2.83, 95% CI, 1.67-4.77, P < 0.01) were significantly associated with poor survival. CONCLUSION: Accurate prognostic factors are important in deciding the treatment strategy in patients with spinal metastasis, and our identification of these factors may be useful for these patients. LEVEL OF EVIDENCE: 3.

Postoperative Complications Associated With Spine Surgery in Patients Older Than 90 Years: A Multicenter Retrospective Study.

STUDY DESIGN: A review of a prospective database. OBJECTIVES: Surgery for elderly patients is increasing yearly due to aging of society and the desire for higher quality of life. The goal of the study was to examine perioperative complications in spine surgery in such patients. METHODS: A multicenter study of surgical details and perioperative complications was performed in 35 patients aged older than 90 years who underwent spinal surgery, based on a review of a prospective database. The frequency and severity of complications were assessed, and the effects of patient-specific and surgical factors were examined. Major complications were defined as those that were life threatening, required reoperation in the perioperative period or left a permanent injury. Ambulatory function before and after surgery was also analyzed. RESULTS: Perioperative complications occurred in 19 of the 35 cases (54%), and included 11 cases of postoperative delirium, most of which occurred after cervical spine surgery. There were 8 major complications (23%), including cerebral infarction (n = 3), coronary heart disease (n = 3), pulmonary embolism (n = 1), and angina (n = 1). Preoperative motor deficit, operative time, estimated blood loss, and instrumented fusion were significantly associated with major complications. An improved postoperative ambulatory status occurred in 61% of cases, with no change in 33%, and worsening in 2 cases (6%). CONCLUSIONS: Timing of surgery before paralysis progression and reduced surgical invasiveness are important considerations in treatment of the very elderly. Improved outcomes can be obtained with better management of spine surgery for patients aged 90 years or older.

Factors Affecting the Severity of Neurological Disorders in Thoracic Idiopathic Spinal Cord Herniation.

STUDY DESIGN: Retrospective multicenter case-controlled study. OBJECTIVE: The objective of this study was to quantitatively examine imaging findings of idiopathic spinal cord herniation (ISCH) and determine the relationship between the image findings and the severity of pre- and postoperative neurological symptoms. SUMMARY OF BACKGROUND DATA: Many radiographic types of ISCH have been identified with regard to the location of the hernial opening or amount of herniated spinal cord. However, few previous studies have investigated the relationship between radiographic findings and the severity of neurological symptoms. METHODS: Of 30,469 patients who underwent spinal surgery at 7 hospitals, 18 patients who underwent surgery for ISCH were identified. Their preoperative neurological severity, disease duration, magnetic resonance imaging findings, computed tomography myelography findings, surgical findings, and postoperative improvements were retrospectively examined. The spinal cord kink angle and minimum cord occupancy rate within the dural tube were measured. In addition, herniation was classified according to the location of the hiatus as either central (type C) or lateral (type L) type. RESULTS: A negative correlation was found between the spinal cord kink angle and the minimum cord occupancy rate. Patient age was significantly higher in the severe paralysis group than in the mild paralysis group. In addition, the number of patients with type C herniation and the kink angle were significantly higher in the severe paralysis group. The number of patients with type L herniation was higher in the significant recovery group than in the mild recovery group; however, the difference was not significant. CONCLUSION: Patients with a large spinal cord kink angle had a smaller spinal cord occupancy rate within the dural tube, and this resulted in severe preoperative conditions. Type C ISCH cases had a severe preoperative neurological deficit and poor postoperative neurological recovery, and the spinal cord in such cases might be damaged irreversibly. LEVEL OF EVIDENCE: 4.

Clinical and Radiographical Differences Between Thoracic Idiopathic Spinal Cord Herniation and Spinal Arachnoid Cyst.

STUDY DESIGN: A retrospective, multicenter, case-controlled study. OBJECTIVE: The aim of this study was to investigate the clinical and radiographical differences between thoracic idiopathic spinal cord herniation (ISCH) and spinal arachnoid cyst (SAC). SUMMARY OF BACKGROUND DATA: ISCH and SAC are relatively rare diseases. Preoperative misdiagnose was frequently reported in both; however, these clinical and radiographical differences remain unclear. METHODS: Of 30,469 patients who underwent spinal surgery, 18 (0.059%) and 22 (0.072%) patients were diagnosed as ISCH or SAC at nine hospitals, respectively, and their clinical and radiographical data were retrospectively evaluated. The spinal cord kink angle was measured on magnetic resonance or computed tomography myelography sagittal images; the kink angle was the exterior angle formed between the two tangents to the dorsal-side inflection points at the maximally affected level. RESULTS: There were no significant differences in age, gender, and duration of symptoms. Preoperative motor deficit was significantly higher (94.4%) and severer (manual muscle testing: 3.1 ±â€Š1.1) in ISCH. Brown-Séquard syndrome was observed in 38.9% of ISCH, while no patients in SAC. In addition, leg sensory disorder and bladder rectal disorder were significantly more common in ISCH, while back pain was significantly frequent in SAC. With respect to radiographical findings, the length of disease (5.1 ±â€Š2.7 levels) and altered cerebrospinal flow (CSF) (81.8%) in the lesion was significantly longer and more common in SAC. On the contrary, the kink angle was significantly greater in ISCH (54.0 ±â€Š23.1°) than in SAC (14.1 ±â€Š12.0°) (P < 0.001). The cut-off value of the kink angle to distinguish ISCH and SAC was 32.8°. CONCLUSION: Patients with ISCH commonly had severe preoperative neurological deficit, Brown-Séquard syndrome, and higher kink angle, while patients with SAC had back pain, longer length of disease, and altered CSF in the lesion. LEVEL OF EVIDENCE: 4.

Fatal case of cervical blunt vascular injury with cervical vertebral fracture: a case report.

Blunt cerebrovascular injury (BCVI) is usually caused by neck trauma that predominantly occurs in high-impact injuries. BCVI may occur due to damage to both the vertebral and carotid arteries, and may be fatal in the absence of appropriate treatment and early diagnosis. Here, we describe a case of cerebral infarction caused by a combination of a lower cervical spinal fracture and traumatic injury to the carotid artery by a direct blunt external force in a 52-year-old man. Initially, there was no effect on consciousness, but 6 hours later loss of consciousness occurred due to traumatic dissection of the carotid artery that resulted in a cerebral infarction. Brain edema was so extensive that decompression by emergency craniectomy and internal decompression were performed by a neurosurgeon, but with no effect, and the patient died on day 7. This is a rare case of cerebral infarction caused by a combination of a lower cervical spinal fracture and traumatic injury to the carotid artery. The case suggests that cervical vascular injury should be considered in a patient with a blunt neck trauma and that additional imaging should be performed.

Cervical epidural hematoma in a healthy donor presenting stroke mimic symptoms: a rare adverse event following peripheral blood stem cell apheresis.

Peripheral blood stem cell apheresis from a healthy donor is indispensable for allogeneic peripheral blood stem cell transplantation. Here, we report a rare adverse event following peripheral blood stem cell apheresis. A female sibling donor, aged 61 years with an unremarkable medical history, complained of pain in the left neck and shoulder and numbness in the left upper limb 1 h after the end of peripheral blood stem cell apheresis. Paralysis of the left upper and lower limbs appeared consecutively. Computed tomography and magnetic resonance imaging of the head showed no abnormalities. Anticoagulant therapy was initiated according to the standard treatment of atherothrombotic brain infarction. Magnetic resonance imaging of the cervical cord on the following day revealed a cervical epidural hematoma. An emergency C4-C5 laminectomy was performed, and the paralysis was improved immediately after surgery. This report is the first case of cervical epidural hematoma in a healthy donor who underwent peripheral blood stem cell apheresis and presented symptoms confusingly similar to those of brain infarction.

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.

Intradural disc herniation: radiographic findings and surgical results with a literature review.

OBJECTIVE: To report a series of four cases of intradural disc herniation (IDH) with a review of the literature. SUMMARY OF BACKGROUND DATA: IDH is a rare type of disc herniation. Preoperative diagnosis is difficult and IDH is only confirmed during surgery in most cases. Here, we describe four cases of IDH, including three with lumbar hernia and one with thoracic hernia. METHODS: A retrospective chart review, surgical database query, and review of radiology reports are presented for each case, along with a literature review of IDH. RESULTS: Two of the four patients had a history of surgery at the same spinal level. Ring enhancement in gadolinium-enhanced MRI, an air image in computed tomography, and complete block in myelography were observed in the series. Surgery was performed with a transdural approach in all patients. One patient underwent transforaminal lumbar interbody fusion after postoperative recurrence. Three patients with lumbar involvement had nerve root symptoms preoperatively, but showed symptomatic improvement in the early postoperative period. In contrast, the patient with thoracic involvement had preoperative muscle weakness due to myelopathy symptoms, and had residual symptoms after surgery. CONCLUSIONS: IDH is a rare disease and characteristic imaging findings can be useful for diagnosis. Intraoperative findings lead to a definitive diagnosis in many cases and recognition of the pathological characteristics of IDH is important.

Characteristics and surgical results of the distal type of cervical spondylotic amyotrophy.

OBJECT: Cervical spondylosis that causes upper-extremity muscle atrophy without gait disturbance is called cervical spondylotic amyotrophy (CSA). The distal type of CSA is characterized by weakness of the hand muscles. In this retrospective analysis, the authors describe the clinical features of the distal type of CSA and evaluate the results of surgical treatment. METHODS: The authors performed a retrospective review of 17 consecutive cases involving 16 men and 1 woman (mean age 56.3 years) who underwent surgical treatment for the distal type of CSA. The condition was diagnosed on the basis of cervical spondylosis in the presence of muscle impairment of the upper extremity (intrinsic muscle and/or finger extension muscles) without gait disturbance, and the presence of a compressive lesion involving the anterior horn of the spinal cord, the nerve root at the foramen, or both sites as seen on axial and sagittal views of MRI or CT myelography. The authors assessed spinal cord or nerve root impingement by MRI or CT myelography and evaluated surgical outcomes. RESULTS: The preoperative duration of symptoms averaged 11.8 months. There were 14 patients with impingement of the anterior horn of the spinal cord and 3 patients with both anterior horn and nerve root impingement. Twelve patients were treated with laminoplasty (plus foraminotomy in 1 case), 3 patients were treated with anterior cervical discectomy and fusion, and 2 patients were treated with posterior spinal fixation. The mean manual muscle testing grade was 2.4 (range 1-4) preoperatively and 3.4 (range 1-5) postoperatively. The surgical results were excellent in 7 patients, good in 2, and fair in 8. CONCLUSIONS: Most of the patients in this series of cases of the distal type of CSA suffered from impingement of the anterior horn of the spinal cord, and surgical outcome was fair in about half of the cases.

Risk factors for a poor outcome following surgical treatment of cervical spondylotic amyotrophy: a multicenter study.

INTRODUCTION: Cervical spondylotic amyotrophy (CSA) is characterized by muscle atrophy in the upper extremities without gait disturbance. However, the indications and outcomes of surgical treatment for CSA have not been clarified. The purpose of this study was to determine the risk factors for a poor outcome following surgical treatment of CSA. MATERIALS AND METHODS: We performed a retrospective review of CSA in patients from 1991 to 2010 through a multicenter study. We collected information regarding age, type of muscle atrophy, preoperative manual muscle test (MMT), duration of symptoms, high-intensity areas on T2-weighted MR images, low-intensity areas on T1-weighted MR images, levels of spinal canal stenosis, cervical kyphosis and surgical procedures (laminoplasty, anterior cervical discectomy and fusion and posterior spinal fusion), and calculated overall risk factors related to a poor outcome following surgery. Univariate analyses and multivariate logistic regression analysis were performed to identify correlates of a poor outcome. RESULTS: Fifty-nine patients, 95 % male (56 patients), were included in our analysis with a mean age of 59 years (range 32-78 years). Eighteen patients did not improve after surgery. Symptom duration (OR = 1.263), preoperative MMT grade (OR = 0.169) and distal type of CSA (OR = 9.223) were all associated with an increased risk of a poor surgical outcome. CONCLUSION: Early surgery is recommended for CSA patients in whom conservative treatment has not been successful. We also recommend surgery for patients who have severe preoperative muscle weakness or have the distal type of CSA.

Primary spinal cord tumors: review of 678 surgically treated patients in Japan. A multicenter study.

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

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.

Microcomputed tomographic evaluation of vertebral microarchitecture in pinealectomized scoliosis chickens.

Pinealectomy was used to induce scoliosis in Broiler chickens, and the bone microarchitecture of the concave and convex sides in pinealectomized scoliosis chickens was assessed by microcomputed tomography (micro-CT). Few studies have assessed the vertebrae bone microarchitecture of the concave and convex sides in scoliosis although the curvature of the coronal plane is the main deformity in scoliosis. The purpose of this study was to determine whether there are differences in the bone microarchitecture of the concave and convex sides in pinealectomized scoliosis chickens by the technique of micro-CT. The etiology and the pathogenesis of the idiopathic scoliosis remain unclear. Limited information is available on the microarchitecture of vertebrae bone of the concave and convex sides of scoliosis, especially in the earlier stage in scoliosis development. One hundred female Broiler chickens were divided into three groups as follows: the control group (n=20), the sham operation group (n=20), and the pinealectomy group (n=60). Then the pinealectomy group was divided into three groups according to the time of killing the chickens: 1-week after the operation (group P-1 w, n=20), 2 weeks after the operation (group P-2 w, n=20), and 3 weeks after the operation (group P-3 w, n=20), respectively. Posteroanterior radiographs of the spine were taken to detect spinal curvature. Using micro-CT, the bone volume/tissue volume (BV/TV), trabecular thickness (Tb.Th), trabecular number (Tb.N), and trabecular separation of the concave and convex sides of the apex vertebrae in the scoliotic chickens were determined. Independent t-tests were used to assess differences of bone parameter of the concave and convex sides in each pinealectomized group. The incidences of scoliosis in the pinealectomized Broiler chickens were 84.2% (group P-1 w), 88.9% (group P-2 w), and 89.5% (group P-3 w), respectively. In groups P-1 w and P-2 w, there were no differences between the concave and convex trabecular bone microarchitectures. In group 3 w, the BV/TV, Tb.Th, and Tb.N of the concave side were significantly greater than those of the convex side. In the earlier stage of pinealectomized scoliosis chickens, there are no histological evidence of a metabolic abnormality. The greater BV/TV, Tb.Th, and Tb.N of the concave side in group P-3 w may be consistent with Wolff's law and are the secondary response to the scoliotic deformity.

An arterial pulse examination is not sufficient for diagnosis of peripheral arterial disease in lumbar spinal canal stenosis: a prospective multicenter study.

STUDY DESIGN: Prospective, multicenter study. OBJECTIVE: To conduct peripheral arterial disease (PAD) screening on intermittent claudication (IC) in patients with lumbar spinal canal stenosis (LSCS) to examine the relationships among combined LSCS and PAD, symptoms, and physical findings. SUMMARY OF BACKGROUND DATA: IC occurs due to two underlying diseases, LSCS and PAD, and has an increasing prevalence with the aging of society. Reliable diagnosis of PAD is critical for appropriate conservative management of IC patients with LSCS in an Orthopedic Surgery Outpatient Department (OSOPD). METHODS: PAD tests were prospectively conducted in 201 patients with IC and LSCS who initially visited an OSOPD at a hospital affiliated with the Nogoya Spine Group. Occurrence of PAD as a complication was assessed using ankle brachial pressure index (ABI) and toe brachial pressure index (TBI) tests. PAD was diagnosed in patients with ABI ≤ 0.9 or TBI ≤ 0.6, and the relationship of the occurrence of PAD with symptoms and physical findings such as abnormal arterial pulses was investigated. RESULTS: Combined LSCS and PAD was found in 52 patients (26%), with 45 cases (22%) diagnosed on the basis of TBI test in patients with a normal ABI. Of the patients with PAD, many suffered from risk factors for PAD, with a significantly higher frequency of PAD in patients with hyperlipidemia (P < 0.05). PAD also occurred significantly more frequently in patients with abnormal pulses in the popliteal (P < 0.05), posterior tibial (P < 0.0001), and dorsal pedis (P < 0.0001) arteries; however, the sensitivity of these tests for PAD diagnosis was relatively low, at 34%, 60% and 68%, respectively. CONCLUSION: The results of the prospective study define the rate of occurrence of combined LSCS and PAD using ABI and TBI tests for the first time, and the findings suggest that screening for PAD should be conducted in LSCS patients. ABI and TBI tests are necessary for PAD screening in outpatients, whereas observation of the arterial pulse in the lower extremities is necessary but not sufficient for PAD diagnosis.