Journal of neurosurgery
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Journal of neurosurgery · Aug 1995
Case ReportsIschemic optic neuropathy following lumbar spine surgery. Case report.
This 48-year-old hypertensive man, a cigarette smoker, awoke in the recovery room with visual loss in the right eye after uncomplicated lumbar spine surgery. His intraoperative blood pressure had been maintained at relatively low levels to reduce bleeding; a loss of 1500 cc of blood was reported. Postoperative hemoglobin was 4.2 g/dl less than the preoperative hemoglobin; however, the patient did not receive a blood transfusion. ⋯ The right optic nerve and retina were initially normal but the patient eventually developed optic nerve atrophy consistent with the clinical diagnosis of ischemic optic neuropathy. Neurosurgeons should be aware that this condition may follow uncomplicated lumbar spine surgery and should obtain prompt ophthalmological consultation when patients develop postoperative visual loss. Aggressive and rapid correction of blood pressure and hematocrit may be helpful in individuals who develop ischemic optic neuropathy after lumbar spine surgery.
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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
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.