Minimally invasive posterior cervical arthrodesis and fixation.

This article describes the use of minimally invasive posterior cervical arthrodesis and internal fixation for the subaxial cervical spine. Such systems vary by the angulation of their screws and in the degree of the constraint placed at the screw-rod interface. The polyaxial tulip or islet connectors of the screws are able to angle medially, laterally, and straight, with varying degrees of rotational freedom in each direction, thus making segmental fixation more easily achievable from a top-loading approach and allowing for the possibility of minimally invasive posterior cervical fixation.

Treatment of lumbar synovial cysts using minimally invasive surgical techniques.

OBJECT: Lumbar synovial cysts are a potential cause of radiculopathy and back pain, and the definitive treatment is the complete excision of the cyst. This report summarizes the authors' preliminary clinical experience with the minimally invasive resection of lumbar synovial cysts. METHODS: Nineteen patients (nine men and 10 women) with symptomatic synovial cysts underwent minimally invasive resection. The mean patient age was 64 years of age (range 43-80 years). The presenting symptom was radiculopathy in 16 patients, low-back pain in two, and lower-extremity weakness in one. There were 16 cases of a cyst located at the L4-5 level, two at L3-4, and one at L5-S1. The mean cyst diameter was 13.7 mm (range 3-30 mm). The mean follow-up time was 16 months (range 4-29 months). Clinical outcomes were graded, based on the Macnab modified criteria, as excellent, good, fair, or poor. Eighteen patients (95% of cases) reported either excellent (10 patients) or good (eight patients) results, and a fair result was reported by one patient (5% of cases). The mean operative time was 158 minutes (range 75-270 minutes), and the average intraoperative blood loss was 31 ml (range 10-100 ml). Two patients had intraoperative dural tears that resulted in cerebrospinal fluid leaks that resolved following primary closure. CONCLUSIONS: Synovial cysts can be safely and effectively treated using minimally invasive surgical techniques. Long-term follow up is required to determine whether this approach results in less need for fusion than conventional surgical approaches.

A genetic strategy to overcome the senescence of primary meningioma cell cultures.

Even though meningiomas are the second most common brain tumor in adults, little is known about the molecular basis of their growth and development. The lack of suitable cell culture model systems is an impediment to this understanding. Most studies on meningiomas rely on primary, early passage cell lines that eventually senesce or a few established cell lines that have been derived from aggressive variants of meningiomas. We have isolated three primary meningioma cell lines that are negative for telomerase activity. We can overcome the senescence of a Grade III derived meningioma cell line by expressing the telomerase catalytic subunit (hTERT), whereas Grade I meningioma cell lines require the expression of the human papillomavirus E6 and E7 oncogenes in conjunction with hTERT. Meningioma cell lines, immortalized in this manner, maintain their pre-transfection morphology and form colonies in vitro. We have confirmed the meningothelial origin of these cell lines by assessing expression of vimentin and desmoplakin, characteristic markers for meningiomas. Additionally, we have karyotyped these cell lines using array CGH and shown that they represent a spectrum of the genetic diversity seen in primary meningiomas. Thus, these cell lines represent novel cellular reagents for investigating the molecular oncogenesis of meningiomas.