Journal of neurosurgery
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Journal of neurosurgery · Aug 1995
Biomechanical analysis of bone mineral density, insertion technique, screw torque, and holding strength of anterior cervical plate screws.
✓ The bone mineral density (BMD) of 99 cadaveric cervical vertebral bodies (C3-7) was determined using dual x-ray absorptiometry. The vertebral bodies were randomly assigned to receive either a unicortical (51 bodies) or bicortical (48 bodies) Caspar cervical plating screw. The initial insertion torque was measured using a digital electronic torque wrench, and the force required to withdraw the screw from the vertebral body was determined. ⋯ The calculated holding index and resultant pullout force were significantly correlated for both techniques of screw insertion (r = 0.92), and a significant difference in holding index was observed with unicortical versus bicortical screw placement (p = 0.04). The determination of BMD and measurement of insertion torque to create a unique holding index provides an assessment of bone-screw interaction and holding strength of the screw, both of which impact on the resultant stability of cervical instrumentation. As the number of cervical plating systems increases, the determination of a holding index for various screws and insertion techniques may assist in the comparison of cervical instrumentation.
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Journal of neurosurgery · Jul 1995
Electrical stimulation of the trigeminal nerve root for the treatment of chronic facial pain.
Between March 1990 and December 1992, 23 patients with chronic intractable facial pain due to various forms of injury to the trigeminal nerve or nerve root underwent implantation of an electrical stimulating system to treat their pain. All patients had failed previous extensive pain treatment efforts. A monopolar platinum-iridium electrode was implanted on the trigeminal nerve root via percutaneous puncture of the foramen ovale. ⋯ Although changes in the patterns of analgesic medication usage were few, six patients (26%) now experience a normal life style. Only one complication was seen, namely a dislocated electrode, which was easily replaced. Chronic electrical stimulation of the trigeminal nerve root appears to be an easy and safe technique for providing relief of chronic facial pain related to injury to the trigeminal nerve in a significant number of patients.
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Journal of neurosurgery · Jul 1995
Case ReportsAneurysm of a persistent primitive olfactory artery. Case report.
A ruptured anterior cerebral artery (ACA) aneurysm is reported in a patient in whom an anomalous ACA arose from the internal carotid artery at the bifurcation. The aberrant artery coursed anteriorly along the ipsilateral olfactory tract and made a hairpin turn posterior to the olfactory bulb, supplying the circulation of the ACA. Persistence of the primitive olfactory artery is suggested as an embryological origin of this vascular anomaly.