Junichi Ukai

Ponte Osteotomy During Dekyphosis for Indirect Posterior Decompression with Ossification of Posterior Longitudinal Ligament of the Thoracic Spine.

Study Design: Retrospective clinical study. Purpose: To investigate the outcomes after indirect posterior decompression and dekyphosis using multilevel Ponte osteotomies for ossification of the posterior longitudinal ligament (OPLL) of the thoracic spine. Summary of Background Data: There are no previous reports on the use of Ponte osteotomy to treat thoracic OPLL. Methods: The subjects were 10 patients with an average age at surgery of 47 years, who underwent indirect posterior decompression and dekyphosis using multilevel Ponte osteotomies at our institute. Minimum follow-up period was 2 years, and averaged 2 year 6 months. Using radiographs and CT images, we investigated fusion range, preoperative and postoperative Cobb angles of thoracic fusion levels, intraoperative ultrasonography, and clinical results. Results: The mean fusion area was 9.8 vertebraes, with average laminectomy of 7.3 laminas. The mean preoperative thoracic kyphosis of fusion levels on standing radiograph measured 35 degrees and was changed to 21 degrees after surgery. The mean number of Ponte osteotomies was 3 levels. The mean preoperative and postoperative (at the 1 y follow-up) JOA scores were 3.5 and 7.5 points, respectively, and the recovery rate was 56%. On intraoperative ultrasonography, 7 of the cases were included in the floating (+) and 3 in the floating (−) groups, and the recovery rates were 66.0% and 33.4%, respectively. Conclusions: “The Ponte procedure for indirect spinal cord decompression” is a novel concept used for the first time with thoracic OPLL in our study, and we consider it a useful method to achieve more effectively dekyphosis and indirect spinal cord decompression if there is not the spinal cord free from OPLL on intraoperative ultrasonography after only laminectomies.

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.

Radiologic evaluation after posterior instrumented surgery for thoracic ossification of the posterior longitudinal ligament: union between rostral and caudal ossifications.

Study Design: Retrospective clinical study. Objective: To investigate, using multislice CT images, how thoracic ossification of the posterior longitudinal ligament (OPLL) changes with time after thoracic posterior fusion surgery. Summary of Background Data: Few studies have evaluated thoracic OPLL preoperatively and post using computed tomography (CT). Methods: The subjects included 19 patients (7 men and 12 women) with an average age at surgery of 52 years (38-66 y) who underwent indirect posterior decompression with corrective fusion and instrumentation at our institute. Minimum follow-up period was 1 year, and averaged 3 years 10 months (12–120 mo). Using CT images, we investigated fusion range, preoperative and postoperative Cobb angles of thoracic fusion levels, intraoperative and postoperative blood loss, operative time, hyperintense areas on preoperative MRI of thoracic spine and thickness of the OPLL on the reconstructed sagittal, multislice CT images taken before the operation and at 3 months, 6 months and 1 year after surgery. The basic fusion area was 3 vertebrae above and below the OPLL lesion. Results: The mean operative time was 7 hours and 48 min (4 h 39 min–10 h 28 min), and blood loss was 1631 mL (160–11,731 mL). Intramedullary signal intensity change on magnetic resonance images was observed at the most severe ossification area in 18 patients. Interestingly, the rostral and caudal ossification regions of the OPLLs, as seen on sagittal CT images, were discontinuous across the disk space in all patients. Postoperatively, the discontinuous segments connected in all patients without progression of OPLL thickness by 5.1 months on average. Conclusions: All patients needing surgery had discontinuity across the disk space between the rostral and caudal ossified lesions as seen on CT. This discontinuity was considered to be the main reason for the myelopathy because a high-intensity area on magnetic resonance imaging was seen in 18 of 19 patients at the same level. Rigid fixation with instrumentation may allow the discontinuous segments to connect in patients without a concomitant thickening of the OPLL.

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.

Progressive relapse of ligamentum flavum ossification following decompressive surgery.

Thoracic ossification of the ligamentum flavum (T-OLF) is a relatively rare spinal disorder that generally requires surgical intervention, due to its progressive nature and the poor response to conservative therapy. The prevalence of OLF has been reported at 3.8%-26%, which is similar to that of cervical ossification of the posterior longitudinal ligament (OPLL). The progression of OPLL after cervical laminoplasty for the treatment of OPLL is often shown in long-term follow-up. However, there have been no reports on the progression of OLF following surgery. We report a case of thoracic myelopathy secondary to the progressive relapse of OLF following laminectomy.

Treatment for primary spinal atypical teratoid/rhabdoid tumor

Atypical teratoid/rhabdoid tumor (AT/RT) of the central nervous system (CNS) is an uncommon condition that accounts for only 1.3% of primary CNS tumors. It is a highly aggressive neoplasm that commonly occurs in infants and children younger than 3 years of age [1–5]. AT/ RT of the CNS is often located in the posterior fossa [6, 7]; primary spinal AT/RT is extremely rare [8–11]. Medulloblastoma (MB) and a prototype primitive neuroectodermal tumor (PNET) are the most common malignant CNS tumors in children [2, 5], and it can be challenging to differentiate spinal AT/RT from spinal PNET [12]. However, differentiation is necessary because AT/RT has a poor prognosis compared with that of PNET, with median survival for AT/RT of approximately 6 months [13–15]. Thus, AT/RTs may be among the most malignant CNS tumors. Several reports of AT/RT in the CNS are available, but only a few cases of primary spinal AT/RT have been described and there is no standard treatment for spinal AT/RT. Here, we report a surgical case with adjuvant therapy for primary spinal AT/RT in a child, and we review the literature on the topic. Consent for publication was obtained from the parents of the patient.

The relationship between spinal and pelvic parameters in the Japanese patients with adolescent idiopathic scoliosis

Several studies have shown that sagittal pelvic morphology influences the sagittal spinal morphology in normal adults. However, the relationship between pelvic and spinal parameters throughout the growth process in children is poorly defined in Japan. This study aimed to clarify the influence of pelvic parameters on spinal parameters in the Japanese children with idiopathic scoliosis.