Characterization of the technique involved in isolating Schwann cells from adult human peripheral nerve

Only recently has it been possible to isolate large quantities of adult derived Schwann cells (SCs) from peripheral nerves in cell culture. These techniques can be easily applied to the isolation of human SCs. We evaluated the influence of donor age and length of explant culture time on the purity of the human SC preparations obtained from a large number ( n = 35) of live organ donors ranging in age from 1 to 63 years. The average SC purity from all donors was 92.7 ± 2.73% and did not appear to be influenced by donor age or duration of culture time in excess of 1 week. Myelin debris was a prominent feature of human SCs prepared in culture and could be detected within histological sections of cultured peripheral nerve segments as well as within human SCs obtained from enzymatic dissociation of the peripheral nerves. This report supports the reproducibility of the techniques involved in isolating human SCs from peripheral nerve from a large series of donors and addresses the mechanism in which a period of cell culture permits the isolation of large quantities of adult human SCs

INFECTIONS OF THE LUMBAR SPINE-TREATMENT OPTIONS

ABSTRACT With advances in antimicrobial therapy, diagnostic techniques, and operative intervention, the overall morbidity and mortality associated with spine infections has been greatly reduced. These infections can be devastating, as the population most at risk are the elderly and/or immunocompromised. Given the poor prognosis without appropriate therapy and the relative rarity of these disorders, a high index of suspicion is paramount to facilitate early diagnosis and expeditious treatment. Current concepts in the management of both pyogenic vertebral osteomyelitis and spinal epidural abscess are reviewed in this article with a special emphasis on the lumbar spine

Management of Posttraumatic Syringomyelia Using an Expansile Duraplasty

Study Design. A patient in whom posttraumatic syringomyelia developed 34 years after an L2 fracture is reported. Objectives. To review the pathophysiology and current management modalities for posttraumatic syringomyelia. The delayed presentation and management rationale of this case are emphasized. Summary of Background Data. This case represents the most delayed onset of symptoms from a posttraumatic syrinx reported in the literature. Although lysis of arachnoid adhesions and expansile duraplasty to recreate the subarachnoid space have been described for nonshuntable syrinxes, this form of management was used as the primary management modality in this case. Methods. A posttraumatic syrinx was managed by lysis of the arachnoid adhesions, fenestration of the cyst, and an expansile duraplasty. Results. After surgery, the patient\u27s symptoms improved, and magnetic resonance imaging showed a decrease in the size of the syrinx. Conclusion. Posttraumatic syringomyelia represents one of the few surgically remediable presentations of spinal cord injury. Consequently it is necessary to continuously develop and monitor new management options for this disease. In the case reported here, the syrinx was treated successfully without the implanting a drainage tube

Minimally Invasive Lateral Mass Screw Fixation in the Cervical Spine: Initial Clinical Experience with Long-term Follow-up

Abstract OBJECTIVE: Lateral mass screw fixation of the subaxial cervical spine has been a major advancement for spinal surgeons. This technique provides excellent three-dimensional fixation from C3 to C7. However, exposure of the dorsal spinal musculature can produce significant postoperative neck pain. The incorporation of a minimal access approach using tubular dilator retractors can potentially overcome the drawbacks associated with the extensive muscle stripping needed for traditional surgical exposures. METHODS: A retrospective analysis was performed on the first 18 patients treated using lateral mass screws placed in a minimally invasive fashion. All patients, except 2 who were lost to follow-up, had a 2-year minimum clinical follow-up. All patients had a computed tomography (CT) scan in the immediate postoperative period to check the positioning of implanted hardware. Operative time, blood loss, and complications were ascertained. Fusion was assessed radiographically with dynamic radiographs and CT scans. RESULTS: Sixteen of the 18 patients underwent successful screw placement. Two patients had the minimal access procedure converted to an open surgery because radiographic visualization was not adequate in the lower cervical spine. Six cases involved unilateral instrumentation and 10 had bilateral screws. A total of 39 levels were instrumented. There were no intraoperative complications, and follow-up CT scans demonstrated no bony violations except in cases where bicortical purchase was achieved. All patients achieved bony fusion. CONCLUSION: A minimally invasive approach using tubular dilator retractors can be a safe and effective means for placing lateral mass screws in the subaxial cervical spine. Up to two levels can be treated in this manner. This approach preserves the integrity of the muscles and ligaments that maintain the posterior tension band of the cervical spine but requires adequate intraoperative imaging

Studies of Myelin Formation after Transplantation of Human Schwann Cells into the Severe Combined Immunodeficient Mouse

We have previously demonstrated (J. Neurosci., 14: 1309-1319) that Schwann cells (SCs) isolated from adult human peripheral nerve in tissue culture and then transplanted into an immune-deficient rat can enhance axonal regeneration and myelinate regenerating peripheral axons. We have now (a) compared the capacity of both primary and expanded populations of cultured human SCs to form myelin around regenerating mouse axons when transplanted into a gap within the sciatic nerve of severe combined immunodeficiency (scid) mice and (b) also compared the myelinating capability of these cultured SCs to their counterparts in the native human peripheral nerve xenograft. Schwann cells were isolated from adult human peripheral nerve. Semipermeable guidance channels were filled with a 30% Matrigel solution mixed with either primary human SCs or human SCs expanded with mitogens both at a density of 120 million cells/ml. These channels or a human peripheral nerve xenograft were implanted within a 5-mm gap in the transected sciatic nerve of the scid mice and analyzed after a period of 6 weeks. The presence of human myelin segments was confirmed in both the guidance channels containing human SCs and the xenografts by immunostaining with a monoclonal antibody (592) which specifically recognizes a prominent myelin component, P0, in the human but not in the mouse. Within both the guidance channels and the xenografts there was an invasion of the transplant by host SCs which went on to form myelin around regenerating mouse axons. In this report, we also demonstrate that human SCs that have been expanded in culture with mitogens are capable of forming myelin after transplantation in this experimental paradigm

Multi‐tiered treatment of pressure sores in two cynomologous macaques (Macaca fascicularis)

Successful treatment of one Grade III and two Grade IV pressure sores on two female Macaca fascicularis, subsequent to a T11 hemilaminectomy and left spinal cord hemisection, was achieved through a combined strategy of wound care, diet, and husbandry. Wound care consisted of early and thorough debridement of all necrotic tissue, initial twice daily cleaning with an iodine scrub and application of a multi‐ingredient ointment. Tissue hydrolyzer, a drying agent, vitamin E, ground selenium, and topical antibiotics were applied to the wound during the respective 45‐ and 46‐day courses of treatment. Oral antibiotics were administered; vitamins C and E, and selenium were increased in the diet. No infection occurred and both animals recovered fully to complete the study. Importantly, pressure sores in subsequent study animals were prevented by post‐operative padding of the perch with towel‐covered foam and placement of a wheelchair cushion on the floor of the cage

Chiari I Malformations and Syringomyelia

ABSTRACT The pathogenesis of the Chiari I malformation (CMI) as well as its associated syringomyelic cavity remains relatively vague despite significant recent advances. Multiple theories have been proposed to explain both the origin of the CMI and the development of a syrinx. This article fleshes out the major theories for both of these conditions. The indeterminate quality of this condition can also be seen in its presentation. There are myriad documented presenting signs and symptoms in patients with CMI. The major clinical syndromes and most common signs and symptoms are reviewed. Most importantly for both patient and physician, this lack of consensus extends to treatment. Because of historical unsatisfying surgical results, a multitude of treatment options have been and are currently being proposed for the treatment of both conditions. The major schools of thought with regard to treatment are also reviewed

Intradural spinal arachnoid cysts in adults

Idiopathic arachnoid cysts are rare lesions not associated with trauma or other inflammatory insults. To date, there have been few large series describing the presentation and management of these lesions. Twenty-one cases of intradural spinal arachnoid cysts were identified (1994-2001). Pediatric patients and cases with antecedent trauma were excluded. There were eight women and 13 men with an average age of 52 years. Follow-up averaged 17 months. Cysts were most commonly found in the thoracic spine (81%). Fifteen cysts were dorsal to the spinal cord and six were ventral to the spinal cord. All patients underwent laminectomy with cyst fenestration and radical cyst wall resection. Based upon intraoperative ultrasonography, four cysts were also shunted to the subarachnoid space, and seven patients had an expansile duraplasty with freeze-dried dural allograft. Of the seven patients with syringomyelia, three resolved with extramedullary cyst resection alone. Four required syrinx to subarachnoid shunting. Follow-up MRI demonstrated cyst resolution in all cases. All seven intramedullary syrinxes were decreased in size and four resolved completely. Weakness (100%), hyperreflexia (91%), and incontinence (80%) were more likely to improve than neuropathic pain (44%) and numbness (33%). One patient had increased numbness postoperatively. Ventral cysts are more likely to cause weakness and myelopathic signs. Preoperative symptoms of neuropathic pain and numbness are less likely to improve than weakness and myelopathy. Utilizing intraoperative ultrasound to guide aggressive surgical treatment with the adjuncts of shunting and duraplasty results in a high rate of cyst and syrinx obliteration