Eiren Toh

The importance of preserving disc structure in surgical approaches to lumbar disc herniation.

Study Design This study examined the clinical and radiographic results in patients with lumbar disc herniation treated surgically with one of four procedures: two different methods of herniotomy using a posterior approach and two different methods of percutaneous nucleotomy. Objectives The authors goal was to identify the structural changes in the disc after each of the procedures and to correlate them with the clinical outcome. Summary of Background Data The details of herniotomy procedure via a posterior approach or by percutaneous nucleotomy as described by many authors have not been consistent. Furthermore, previous reviews of these studies have been less than satisfactory. Methods One hundred fifty‐seven herniotomies using a posterior approach and 94 percutaneous nucleotomies were studied with a follow‐up of at least 2 years. Each of these groups was divided into two subgroups to evaluate the role of the remaining nucleus pulposus in the central area of the disc. Results Changes seen in imaging studies, such as a decrease in disc height and an increase of intervertebral instability in plain radiographs and a decrease in signal intensity of the disc in magnetic resonance images, were significantly less common in the subgroups of herniotomy and percutaneous nucleotomy in which the nucleus pulposus in the central area of the disc was preserved when compared with the subgroups in which a complete removal of the disc was attempted. The changes seen in the imaging studies were significant in patients younger than 40 years of age and correlated closely with the clinical results. Conclusions Preserving the nucleus pulposus during the surgical treatment of lumbar disc herniation in patients younger than 40 years of age resulted in better radiographic and clinical results.

Treatment of osteoporotic late collapse of a vertebral body of thoracic and lumbar spine

Although osteoporotic late collapse of a vertebral body is a common infirmity of old age, it has not been well studied, and no consensus regarding treatment of this condition has been reached. Forty-five patients with osteoporotic late collapse of a vertebral body were classified into six types based on the appearance on the lateral projection of a radiograph and the presence or absence of neurologic symptoms and were evaluated on imaging and clinical outcome. We concluded that the treatment of osteoporotic late collapse of a vertebral body can be individualized based on several factors such as the presentation of the fracture and neurologic condition. Conservative treatment can be selected in patients without neurologic involvement who have the concave type with anterior spur or sclerotic change or flat type with uniform compression of collapse. If the patients in those types of collapse show neurologic involvement, decompression and reconstruction through a posterior approach, including an eggshell procedure and the short segment pedicle screw system, are more suitable. Anterior decompression with anterior strut bone graft and anterior spinal instrumentation should be done for wedged type of collapse regardless of neurologic status.

The risks and benefits of percutaneous nucleotomy for lumbar disc herniation: A TEN-YEAR LONGITUDINAL STUDY

Percutaneous nucleotomy is a relatively new technique for treating lumbar disc herniation. There is no agreement as to the volume of disc material to be removed. A long-term study of clinical and radiological data from patients treated by percutaneous nucleotomy was designed to identify the factors associated with favourable and unfavourable outcomes. We studied 42 patients for at least ten years; the mean follow-up was 10.9 years. They were divided into two subgroups to assess the value of preserving the nucleus pulposus in the central area of the disc. The overall success rate for both subgroups was 50%. A decrease in disc height on plain radiography and a decrease in signal intensity on MRI were observed more infrequently in patients in whom the nucleus pulposus in the central area of the disc had been preserved, than in those in whom it had been extensively removed. These adverse radiological findings correlated closely with increased low back pain during the first one to two years after operation and a poorer overall outcome. We conclude that percutaneous nucleotomy is most likely to be successful when the central area of the disc is preserved.

The risks and benefits of percutaneous nucleotomy for lumbar disc herniation

Percutaneous nucleotomy is a relatively new technique for treating lumbar disc herniation. There is no agreement as to the volume of disc material to be removed. A long-term study of clinical and radiological data from patients treated by percutaneous nucleotomy was designed to identify the factors associated with favourable and unfavourable outcomes. We studied 42 patients for at least ten years; the mean follow-up was 10.9 years. They were divided into two subgroups to assess the value of preserving the nucleus pulposus in the central area of the disc. The overall success rate for both subgroups was 50%. A decrease in disc height on plain radiography and a decrease in signal intensity on MRI were observed more infrequently in patients in whom the nucleus pulposus in the central area of the disc had been preserved, than in those in whom it had been extensively removed. These adverse radiological findings correlated closely with increased low back pain during the first one to two years after operation and a poorer overall outcome. We conclude that percutaneous nucleotomy is most likely to be successful when the central area of the disc is preserved.

Intramedullary spinal cord metastasis: a clinical and imaging study of seven patients.

Objectives: Intramedullary spinal cord metastasis (ISCM) is a rare complication of cancer. This complication has been studied by magnetic resonance imaging (MRI) more frequently in the clinical context to improve the survival time of cancer patients. However, the number of the reports of its clinical management or radiographic findings is small. To investigate the clinical and imaging characteristics of ISCM, seven cases of ISCM of a nonneurogenic origin were examined retrospectively. Method: Data regarding the site of the primary neoplasm, location of other metastases, initial symptoms, interval from the original diagnosis of cancer to the onset of neurologic symptoms, time course from initial symptoms to urinary retention, MRI data, and outcome after radiologic or surgical intervention were investigated. Results: Five patients had lung cancer metastases, and one each had breast or uterine cancer metastases. The progression of neurologic deficit was rapid, and the average period between the occurrence of initial symptoms and urinary retention was 25 days. The averaged survival period from the diagnosis of ISCM was 5 months in three patients. (One patient is alive, and the data could not be obtained in another three patients.) MRI characteristics were useful for diagnosis, including large high signal intensity areas on T2-weighted images and strong ring or inhomogeneous enhancement on gadopentetate dimeglumine-enhanced T1-weighted images. Surgery was performed on two patients, but total removal could not be achieved. Radiotherapy was effective in treating neurologic deficit in five patients. Conclusion: Surgical treatment is seldom indicated for ISCM, and radiotherapy is recommended as soon as possible after a diagnosis is made from MRI.

Multiple extradural arachnoid cysts at the spinal cord and cauda equina levels in the young.

Study design:A case report of multiple extradural arachnoid cysts at the spinal cord and cauda equina levels in the young.Objective:To report an exceedingly rare case of multiple extradural arachnoid cysts at the spinal cord and cauda equina levels in the young.Setting:Department of Orthopaedic Surgery, Tokai, Japan.Case report:An 11-year-old boy was diagnosed with multiple extradural arachnoid cysts at the spinal cord and cauda equina levels extending from the T5 to L5 vertebrae and surgery was performed. At 2 years after surgery, no recurrence was observed and muscle weakness of the lower extremities and sensory disturbance improved.Conclusion:Excision of only the arachnoid cysts at the spinal cord level led to a favorable outcome.

Immortalization of Human Nucleus Pulposus Cells by a Recombinant SV40 Adenovirus Vector : Establishment of a Novel Cell Line for the Study of Human Nucleus Pulposus Cells

Study Design. Establishment and characterization of a de novo cell line derived from human nucleus pulposus cells using a recombinant simian virus 40 (SV40) adenovirus vector. Objectives. To assess the feasibility of human nucleus pulposus cell line procurement and to evaluate the character of the resultant outcome to better understand the nature of human nucleus pulposus cells. Summary of Background Data. Despite recent advances in disc cell biologic research, the fundamental nature of nucleus pulposus cells, especially in the context of human cell lines, is still not well understood. Therefore, a broad-based analysis of these cells is of significant necessity. Because of the limited amount of existing human cells, establishment of an immortal cell line would greatly facilitate resource supply. Methods. After release of informed consent, tissue samples of nucleus pulposus were obtained from the lumbar intervertebral disc of a 19-year-old man undergoing anterior fusion for burst fracture. Samples with no apparent damage were selected and digested enzymatically for primary culture and then were infected with recombinant SV40 adenovirus vector (Ad/SV40). The infected cells were maintained in culture for more than 40 population doublings, after which they were considered immortalized. Next, confirmation of expression of T antigen was performed and resultant immortalized cell lines were designated and classified as human nucleus pulposus cell line derived from Ad/SV40 infection-1 (HNPSV-1). HNPSV-1 cells were characterized and compared with their mother cells under two designated culture conditions: monolayer and three-dimensional. Morphologic and immunocytochemical analyses were performed at various intervals. Cell proliferation, DNA synthesis, proteoglycan synthesis, gene expression profiling, and karyotypic analyses were also performed. Moreover, HNPSV-1 cells were injected into rabbit discs to assess the presence of tumorigenesis. Results. Recombinant SV40 adenovirus vector infected nucleus pulposus cells with relatively high efficiency (90%> at multiplicity of infection 100). HNPSV-1 demonstrated marked prolongation of cell life with continuous cell doublings for over 5 months (60–100 cell population doublings). Despite significant increase in cell proliferation and DNA synthesis when compared with its mother cells, resultant cell lines expressed strikingly similar cell morphology and functional characteristics. Atypical karyotypes were noted; however, no apparent tumorigenesis was seen in rabbit discs 24 weeks after injection of HNPSV-1. Conclusions. HNPSV-1 was successfully established using recombinant SV40 adenovirus vector. Results showed that human nucleus pulposus cells are capable of immortalization with maintenance of original cell characteristics. It is anticipated that these cells will be useful for in vitro studies of the biologic nature of human nucleus pulposus cells.

Surgical treatment for injuries of the middle and lower cervical spine

We reviewed the surgical treatment of 31 patients with burst fractures or teardrop dislocation fractures in the middle and lower cervical spine. Patients were treated with anterior instrumentation, posterior instrumentation, or a combination of both. Patients were evaluated radiographically and with the Frankel neurological outcomes grading scale. Anterior decompression and fusion restored the spinal canal diameter by approximately 60% whereas the posterior or combined approaches restored the canal diameter by only 6%. In addition, nine of 24 patients treated anteriorly gained improved neurological function whereas none of the patients treated posteriorly had neurological improvement. Based on the anatomical and neurological findings, the study demonstrates that anterior fusion is preferable to posterior fusion for the treatment of burst fractures and tear-drop dislocation fractures of the middle and lower cervical spine.RésuméNous avons revus le résultat du traitement chirurgical de 31 malades avec une fracture comminutive ou une fracture-luxation en flexion (tear drop) du rachis cervical moyen et inférieur. Les malades ont été traités avec une instrumentation antérieure, une instrumentation postérieure, ou une combinaison des deux. Les malades ont été évalués radiographiquement et avec le score neurologique de Frankel. La décompression-fusion antérieure a restauré le diamètre du canal vertébral approximativement dans 60% des cas, alors que les abords postérieurs ou combinés ont restauré le diamètre du canal dans seulement 6% des cas. De plus, 9 des 24 malades traités par voie antérieure ont vu leur fonction neurologique améliorée, alors qu’aucun des malades traités par voie postérieure n’avait d’amélioration neurologique. Basé sur les conclusions anatomiques et neurologiques, l’étude démontre que la fusion antérieure est préférable à la fusion postérieure pour le traitement des fractures comminutives et des fracture-luxations en flexion de la colonne vertébrale cervicale moyenne et inférieure.

Calcification of the alar ligament of the cervical spine: imaging findings and clinical course

Abstract Ligamentous calcification of the cervical spine has been reported in the yellow ligament, anterior and posterior longitudinal ligaments and interspinous ligament. Calcification in the upper cervical spine is rare, although some cases with calcification of the transverse ligament of the atlas have been reported. Two patients with calcification of the alar ligament with an unusual clinical presentation and course are described. Examination by tomography and computed tomography (CT) showed calcification of the alar ligament and the transverse ligament of the atlas. CT documented decreased calcification as symptoms resolved. There may be a role for CT in the search for calcifications in the upper cervical spine in patients presenting with neck pain and pharyngodynia if radiographs are normal.

Percutaneous Nucleotomy in Elite Athletes

Percutaneous nucleotomy in elite athletes is considered a minimally invasive treatment of lumbar disc herniation. However, long-term effectiveness has not been established by careful follow-up studies. This article evaluates the outcome of percutaneous nucleotomy in elite athletes who have undergone the procedure. Thirty elite athletes with lumbar disc herniation who underwent percutaneous nucleotomy and had been followed for at least 2 years were compared with a matched group of 42 nonathletes. The outcome in athletes was worse than in nonathletes. Early return to vigorous sports activity in less than 3 months correlated with increased symptoms. Similarly, more extensive resection of disc material was associated with an unexpected rapid worsening of the outcome and the lower rate of return to preoperative sports. Patient selection and postoperative management of athletes and nonathletes undergoing percutaneous nucleotomy should be the same, and the procedure in athletes is probably not worthwhile if they do not obey postoperative management such as the timing of return to sports activity.