Masayoshi Oga

Evaluation of the risk of instrumentation as a foreign body in spinal tuberculosis. Clinical and biologic study.

The risk of persistence and recurrence of infection in posterior spinal instrumentation surgery for spinal tuberculosis was studied clinically and microbiologically. Eleven patients with thoracic, thoracolumbar, and lumbar spinal tuberculosis treated by debridement, anterior fusion, and combined posterior instrumentation surgery were analyzed. Seven patients had tuberculosis in both anterior and posterior spinal elements. There were no cases of persistence or recurrence of infection after surgery, and instrumentation provided immediate stability and protected against development of kyphotic deformity. The adherence properties of Mycobacterium tuberculosis to stainless steel (SUS 316) was evaluated experimentally. The results showed that posterior instrumentation surgery was not a hazard to spinal tuberculosis infection when combined with radical debridement and intensive anti-tuberculosis chemotherapy.

Surgical biomaterials and differential colonization by Staphylococcus epidermidis

The data presented in this communication demonstrate preferential colonization of certain biomaterials by Staphylococcus epidermidis. Using a laminar flow biomaterial colonization chamber and surgical-grade biomaterials (stainless steel, aluminium ceramic, methyl methacrylate and high-density polyethylene), the pattern of colonization was quantitated using plate count techniques and electron microscopy. Under comparable conditions, methyl methacrylate was colonized by S. epidermidis in greater numbers than the other biomaterials. Increased bacterial colonization and slime production on methyl methacrylate was time-dependent and 15 times higher than on stainless steel and aluminium and four times higher than on high-density polyethylene. The data reveal that certain biomaterials may promote infection by favouring colonization by potential pathogens. This variable should be explored extensively in an in vivo setting because of its implication in clinical infections.

Tortuosity of the vertebral artery in patients with cervical spondylotic myelopathy: Risk factor for the vertebral artery injury during anterior cervical decompression

Study Design The case report presented herein shows tortuosity of the vertebral artery in a patient with cervical myelopathy. This case led the authors to evaluate 22 other patients who also had undergone anterior cervical fusion. They were studied before operation by either magnetic resonance imaging angiography or selective vertebral angiography. Objectives To analyze the radiographs, computed tomography, magnetic resonance imaging, and angiography findings to detect any tortuosity of the vertebral artery in patients with cervical myelopathy to show the risk factors of vertebral artery injury during anterior decompression. Summary of Background Data Complications of vertebral artery laceration during cervical anterior decompression are rare, so this injury and abnormality in the course of vertebral artery in patients with cervical myelopathy receive little attention. Methods The tortuosity of the vertebral artery was assessed by angiography, magnetic resonance imaging, and computed tomography. Results Mild vertebral artery tortuosity was observed in 10 patients and loop formation in three associated with cervical spondylotic changes. Conclusions This study suggests that vertebral artery loop formation is developed associated with cervical spondylotic changes. During the anterior decompression of cervical spondylotic myelopathy or radiculopathy, the looped vertebral artery could be injured by an excessive wide rejection of the bone or disc material. In the case of vertebral artery migration, the looped vertebral artery can even be injured by routine procedures.

Dysphagia complications in ankylosing spinal hyperostosis and ossification of the posterior longitudinal ligament : roentgenographic findings of the developmental process of cervical osteophytes causing dysphagia

This is the first report of the process of formulation of a cervical osteophyte causing dysphagia, The patient had ankylosing spinel hyperostosis and OPLL and was followed radiographically for a long time before the onset of dysphagia. The radiological observation suggested that dysphagia was produced when the immobile part of the esophagus was compressed by the anterior projecting cervical osteophyte. The immobility of the esophagus is an important factor in determining whether dysphagia occurs. Another possible contributung factor to dysphagia in this patient was the ossification of the cervical anterior and posterior longitudinal ligaments. The OPLL affected intervertebral segmental motion and induced the formation of anterior projecting cervical osteophytes.

Bacterial adherence to bioinert and bioactive materials studied in vitro.

In vitro, bioinert stainless steel and titanium alloy, and bioactive sintered hydroxyapatite and hydroxyapatite-coated titanium materials were exposed to Staphylococcus epidermidis to study bacterial adhesion. Scanning electron microscopy showed that fibrous strands interconnected the adherent bacteria, and that background matrix enclosed bacterial colonies. This adherent mode of growth may reduce the susceptibility of the bacteria to host clearance mechanisms and antibiotic therapy. Adherence assays revealed that bacterial adherence to sintered hydroxyapatite was higher than to the other 3 materials.

Inhibition of bacterial adhesion by tobramycin-impregnated PMMA bone cement.

We investigated the effect of tobramycin-impregnated polymethylmethacrylate (PMMA) bone cement on the adhesion and colonization of Staphylococcus epidermidis. The pattern of colonization was quantitated using plate count techniques and electron microscopy. Colonization of the tobramycin-impregnated disc surface by adhesive bacteria was demonstrated but it was less than in the control disc. This finding suggests that tobramycin may reduce bacterial adherence and proliferation on the PMMA surface.

Clinical Outcome of Microendoscopic Posterior Decompression for Spinal Stenosis Associated with Degenerative Spondylolisthesis − Minimum 2-year Outcome of 37 Patients

A clear consensus for the optimal surgical treatment for spinal stenosis associated with degenerative spondylolisthesis (DS) has not appeared. In general, decompression and fusion are recommended. However, the symptoms of spinal stenosis are the main complaints in almost all patients with DS, and whether or not routine concomitant fusion is necessary in the surgical treatment for DS is still discussed controversially. The authors have treated almost all the patients with spinal stenosis associated with DS by microendoscopic posterior decompression (MEPD) procedures since 2001. In the present study, we examined the minimum 2-year outcome in 37 patients surgically treated with the MEPD procedures for spinal stenosis associated with DS. At the mean of 38 months after surgery, the overall results were excellent in 54% of the patients, good in 19%, fair in 13.5%, and poor in 13.5%, based on the Japanese Orthopedic Association lumbar score, a visual analogue scale, and the Roland-Morris disability questionnaire. Although the progression of spondylolisthesis and the increase of segmental sagittal motion after surgery were seen in 7 patients (19%), only one patient required secondary fusion during the follow-up period. A sufficient decompression with the preservation of the posterior structures of the spine was observed in almost the patients after surgery. In conclusion, the MEPD is a minimally invasive procedure developing a sufficient decompression with the preservation of the spinal stability. Thus, the MEPD is one of the useful procedures in the surgical treatment of spinal stenosis associated with DS. However, further follow-up studies should be performed to evaluate the long-term outcome for evaluation of the true validity of the MEPD for DS.

Herniation of calcified cervical intervertebral disc causes dissociated motor loss in a child.

Herniation of the calcified nucleus pulposus is a rare complication of intervertebral disc calcification in children. Surgical intervention is rarely indicated in the majority of such cases. This paper reports a 12-year-old boy with a calcified nucleus pulposus at C7-T1 which had ruptured into the spinal canal, causing dissociated motor loss. Anterior discectomy and fusion were performed and the patients muscle weakness markedly improved after surgery.

Increased resistance of bacteria after adherence to polymethyl methacrylate: An in vitro study

The pathobiology of total joint prosthesis infection was investigated in vitro. Discs of polymethylmethacrylate (PMMA) were exposed to a suspension containing cells of 10(8) per mL Staphylococcus epidermidis E-46. After 12 hours, exposed discs were rinsed with phosphate-buffered saline and placed in brain heart infusion broth containing antibiotics (2.5 mg per mL of Cephaloridine). After gentle shaking for 24 hours at 37 degrees C, the bacteria on the PMMA surface were detached and washed with phosphate-buffered saline to remove the antibiotics. Compared with the free bacteria which were detached from the PMMA by sonication immediately after exposure to the antibiotic solution, those allowed to remain adhered to the PMMA surface were more resistant to antibiotics. Scanning electron microscopy showed accumulation of bacteria surrounded by slime on PMMA discs exposed for 12 hours. Our results indicate that resistance of bacteria to antibiotics is increased after adherence to the biomaterial and formation of a slime layer.

Treatment of Cervical Cord Compression, Caused by Hereditary Multiple Exostosis, With Laminoplasty : A Case Report

STUDY DESIGN Case report. OBJECTIVES Successful excision of the exostosis within the spinal canal. SUMMARY OF BACKGROUND DATA Myelopathy caused by exostosis within the spinal canal developed in a 13-year-old boy with hereditary multiple exostosis. METHODS Spinous process-splitting laminoplasty with an ultrasonic knife was performed to remove the mass and minimize the possibility of postlaminectomy kyphosis. RESULTS The spinal canal exostosis with cervical cord compression was excised successfully with laminoplasty. After surgery there has been no recurrence of tumor, and the stability of the cervical spine has been preserved. CONCLUSION This is the first report of laminoplasty as a useful surgical approach for intraspinal exostosis to prevent postoperative cervical instability.