Surgical treatment of lumbar spondylolisthesis.

This article provides an overview of studies that address the medical and surgical treatment of lumbar spondylolisthesis, both degenerative and isthmic. Although the efficacy of decompression for symptomatic lumbar stenosis recalcitrant to conservative treatment has been demonstrated, the addition of instrumentation to a fusion procedure remains controversial. The senior author's (VKHS) experience with pedicle screw fixation and fusion for lumbar spondylolisthesis, the addition of interbody fusion, and spinal navigation is reviewed.

Efficacy of pedicle screw fixation in the treatment of spinal instability and failed back surgery: a 5-year review.

OBJECT: The goal of this study was to review retrospectively the outcome of 95 patients with various disorders leading to instability of the thoracolumbar and lumbar spine who were treated consecutively via a posterior surgical approach with pedicle screw fixation in which the Texas Scottish Rite Hospital system was used. METHODS: All cases were managed according to the same protocol. Follow-up review averaged 29.6 months. Radiographic evidence of osseous union and the patient's current status were analyzed. Four screws were malpositioned, and there were two dural lacerations of a nerve root and one pedicle fracture. Deep wound infections developed in five patients (5.2%), and three patients had postoperative radicular pain. In one case, the rods disengaged from the screws; in four cases, hardware was removed but there were no broken screws. Neurological deficits improved in 85% of the surviving patients, and no patient was worse neurologically after surgery. The rate of osseous union was 96.8%. Three patients developed pseudarthrosis, one of whom was asymptomatic. Back pain improved in 80 patients. A solid bone fusion, however, was not necessarily associated with decreased back pain. CONCLUSIONS: These results support the use of pedicle screw fixation as an effective and safe procedure for fusion of the thoracolumbar and lumbar spine and support the finding that complications can be minimal when a meticulous surgical technique is used. The proper selection of patients for surgery is probably the most important factor associated with good outcomes.

Use of the BendMeister rod bender for occipitocervical fusion: technical note.

The creation of various curves in bendable metallic rods remains difficult. We describe a simple instrument that uses two bending levers to provide the mechanical advantage required to easily shape up to 5.5 mm diameter bendable metallic rods with precision, control, and minimal nicking or scratching of the metal surface. We have successfully used this tool to contour primary and secondary curvatures in threaded Steinmann pins and grooved titanium rods for occipitocervical fusion.

Thoracoscopic spinal surgery. Treatment of thoracic instability.

Thoracoscopic spinal surgery is technically feasible and can be performed safely with acceptable rates of morbidity and excellent clinical and neurologic results. Thoracoscopic techniques can be used for anterior decompression and internal fixation in cases in which pathologic processes lead to instability. This minimally incisional access technique can achieve the identical extent of spinal exposure, dissection, decompression, and reconstruction as those obtained with open techniques.

Triple anterior screw fixation of an acute combination atlas-axis fracture. Case report.

The authors report the successful treatment of an acute combination atlas-axis fracture in an 85-year-old man using anterior odontoid and C1-2 transarticular facet screw fixation and a Philadelphia collar. Treatment with halo brace immobilization failed, and the patient experienced recurrent episodes of oxygen desaturation when placed partially prone for chest physiotherapy. If a posterior approach is not feasible, an anterior odontoid and C1-2 transarticular facet screw fixation can be considered as a salvage procedure for patients with acute combination atlas-axis fractures.

Thoracic vertebrectomy and reconstruction using a microsurgical thoracoscopic approach.

A video-assisted thoracoscopic microsurgical approach was developed in the laboratory and subsequently used clinically to resect abnormalities of the thoracic vertebrae, to decompress the thoracic spinal cord, and to reconstruct the thoracic vertebral bodies. This report describes the development of the clinical operative techniques for microsurgical thoracoscopic vertebrectomy, neural decompression, and spinal reconstruction. This minimally incisional approach was clinically used in 17 patients to treat vertebral osteomyelitis, tumors, and compression fractures. Microsurgical thoracoscopic techniques were performed using several narrow, flexible, working portals placed in small incisions in the intercostal spaces. Access to the thoracic spine was achieved through the pleural cavity after temporary deflation of one lung using a double-lumen endotracheal tube. The parietal pleura, segmental vessels, and rib heads were dissected off the surfaces of the involved vertebrae to expose the region of interest. Long narrow spine dissection tools were used to perform the spinal decommpression and reconstruction. This technique achieved the same amount of spinal dissection as that achieved with conventional open spinal procedures and used microsurgical visualization techniques. The small incisions with reduced soft tissue dissection may reduce postoperative pain, shorten the length of hospitalization, and have cosmetic and functional advantages. Thoracoscopic vertebrectomies and reconstruction of the spine were technically feasilble procedures that were performed with excellent clinical results. This minimally incisional technique provides a viable alternative to thoracotomy or to posterolateral approaches for thoracic vertebrectomy and vertebral body reconstruction.

Elevated intracranial venous pressure as a universal mechanism in pseudotumor cerebri of varying etiologies.

Pseudotumor cerebri (PTC), or idiopathic intracranial hypertension, is a syndrome associated with multiple clinical conditions. We hypothesize that most if not all etiologies result in an increase in intracranial venous pressure as a final common pathway. We studied 10 patients with PTC. Five had dural venous outflow obstruction as demonstrated by venography, and the five remaining patients had normal venous anatomy. Pressure measurements, made during venography in eight patients, all showed elevated pressures. Pressure measurements in the superior sagittal sinus ranged from 13 to 24 mm Hg (mean, 16.6 mm HG). Patients with obstruction tended to have a high pressure gradient across the stenotic segment. Five patients with normal dural venous anatomy had elevated right atrial pressures (range, 6 to 22 mm Hg; mean, 11.8 mm Hg), which were transmitted up to the intracranial venous sinuses. Endovascular techniques, including angioplasty and infusion of thrombolytic agents in some cases, improved outlet obstruction from a hemodynamic perspective but were ineffective in consistently and reliably alleviating the clinical manifestations of PTC. Patients in both groups tended to respond well to conventional CSF diversion procedures. Our study suggests that elevated intracranial venous pressure may be a universal mechanism in PTC of different etiologies. This elevated venous pressure leads to elevation in CSF and intracranial pressure by resisting CSF absorption. Although the mechanism leading to venous hypertension in the presence of outflow obstruction is obvious, the etiology of increased intracranial and central systemic venous pressure in PTC remains obscure.

Glossopharyngeal neuralgia associated with vascular compression and choroid plexus papilloma.

We report two cases of presumed idiopathic glossopharyngeal neuralgia that were discovered intraoperatively to be associated with compression by choroid plexus papillomas, and by a variable degree of vascular compression at the root entry zones of cranial nerves IX and X. The combination of the two entities in glossopharyngeal neuralgia has not previously been reported.

Posterior atlantoaxial facet screw fixation.

Eighteen patients with atlantoaxial instability were treated with posterior atlantoaxial facet screws to obtain immediate rigid fixation of C1-2. Of these 18 patients, instability occurred due to trauma in nine, rheumatoid arthritis in six, neoplasms in two, and os odontoideum in one. Four patients presented with nonunion after failed C1-2 wire and graft procedures. In all cases in this series the screw fixations were augmented with an interspinous C1-2 strut graft which was wired in place to provide three-point stabilization and to facilitate bone fusion. In every case fixation was satisfactory, and C1-2 alignment and stability were restored without complications due to instrumentation. One patient died 3 months postoperatively from metastatic tumor; the spinal fixation was intact. All 17 surviving patients have developed osseous unions (mean follow-up period 12 months, range 6 to 16 months). Posterior atlantoaxial facet screw fixation provides immediate multidirectional rigid fixation of C1-2 that is mechanically superior to wiring or clamp fixation. This technique maximizes success without the need for a supplemental rigid external orthosis, and is particularly useful for pseudoarthrosis.

Naloxone stimulation of in vivo LHRH release is not diminished following ovariectomy.

The effects of an opiate receptor antagonist, naloxone, on the in vivo release of luteinizing hormone releasing hormone (LHRH) in ovariectomized and intact female rats were examined using push-pull perfusion. Hypothalamic LHRH release rates were determined before and after naloxone (2.5 mg/kg s.c.) or saline vehicle injection in rats during metestrus or 4 or 8 days following ovariectomy. Naloxone was found to be equally effective in significantly (p less than 0.05) stimulating LHRH release in all three treatment conditions. In animals that were fitted with atrial catheters instead of push-pull cannulae, naloxone administration led to significant increases in peripheral LH levels in metestrous and ovariectomized rats. Peripheral follicle-stimulating hormone levels were unaffected by naloxone. These results suggest that opioid inhibitory tone is not diminished during pituitary escape from ovarian negative feedback in adult female rats. Our findings are not consistent with the hypothesis that ovarian negative feedback regulation of LH secretion is serially mediated by endogenous opioid peptide neurons in these animals. Rather, it is proposed that opioid inhibition of LHRH release and ovarian negative feedback may operate in parallel to control LH secretion in the female rat.