Leslie C. Hellbusch

The long-term clinical outcome of patients undergoing anterior cervical discectomy with and without intervertebral bone graft placement

OBJECTIVE This retrospective study provides data on the long-term clinical outcomes of patients with either anterior cervical discectomy alone (ACD) or anterior cervical discectomy with intervertebral bone graft placement (ACDF). METHODS A questionnaire was mailed to 525 patients who had undergone ACD (290 patients) or ACDF (235 patients) at least 2 years previously. All procedures were performed by University of Nebraska Medical Center faculty in the Section of Neurosurgery. The follow-up period averaged 8.1 years, with a range of 2 to 14 years. RESULTS Two hundred sixty-two (49.9%) patients responded to the questionnaire. There was no demographic difference between respondents and nonrespondents (P > 0.05). Respondents who underwent ACDF reported fewer problems with pain than did those who underwent ACD (P < 0.05). A higher percentage of respondents with ACDF reported that they had normal function than did those who underwent ACD (P < 0.05). When limited to respondents who underwent first-time, single-level operations (191 patients), similar results were obtained for the pain parameter (P < 0.05) but not for the level of function (P = 0.25). Patients with longer follow-up periods had fewer problems with pain and better levels of function (P < 0.05). CONCLUSION Patients who underwent ACD or ACDF did well and benefited from their operations. Those who underwent ACDF did better than those who underwent ACD. Length of follow-up was also an important predictor of current levels of function and pain.

Cerebral arteriovenous malformation in three successive generations

We report a kindred with cerebral arteriovenous malformations in three generations, suggesting autosomal dominant inheritance in this family. Screening asymptomatic persons with a family history for cerebral arteriovenous malformations is discussed.

Magnetic resonance angiography in the diagnosis of traumatic vertebrobasilar complications: A report of two cases

Although conventional arteriography is usually performed to study the vertebrobasilar system, we report two cases of traumatic vertebrobasilar vascular occlusion that were diagnosed by magnetic resonance angiography. This enabled us to promptly treat the patients. Our experience suggests that magnetic resonance angiography may be a useful diagnostic tool in the setting of acute vertebrobasilar complications, associated with cervical spine trauma.

Flow characteristics of cerebrospinal fluid shunt tubing

OBJECT Cerebrospinal fluid shunt systems malfunction for a multitude of reasons, including malpostitioning, obstruction of the ventricular or distal catheter, obstruction of the shunt valve, and catheter disruptions or disconnections. The goal of this study was to examine the hydrodynamic resistance and flow in new and explanted catheters and also in catheters with 1 or 2 straight connectors. METHODS Explanted catheters of multiple lengths, 2-piece catheters, 3-piece catheters, and new catheters were attached to a proximal and distal manometer. A flask with artificial CSF attached to the proximal end provided flow. The flow was allowed to stabilize over 1 hour; then the change in pressure between the proximal and distal end of the catheter was measured. RESULTS The resistance to flow was calculated for new, never-implanted catheters and compared with the resistance of explanted distal shunt catheters. The resistance of the new catheters was examined after the addition of 1 and 2 straight connectors. Explanted catheters exhibited a slight increase in the resistance to flow of artificial CSF compared with new catheters. Two-piece and 3-piece catheters had a significant increase in resistance to flow compared with new catheters. For all catheters, resistance to flow increased as length increased (new, p = 0.01; explanted, p = 0.009; 1 connector, p = 0.01; 2 connectors, p = 0.03). In this paper, effective diameter is defined as the available cross-sectional area of catheter contacted by the artificial CSF. For new and explanted catheters, a decrease in the effective diameter of the catheter was associated with an increase in the resistance to flow of artificial CSF (new, p = 0.1083; explanted, p = 0.0091). However, after the addition of 1 or 2 connectors, an inverse trend was observed: resistance to flow increased with effective diameter. CONCLUSIONS There appears to be some increase in resistance of CSF shunt catheters as they age, altering flow dynamics. In addition, the use of straight connectors within a CSF shunt system increases the resistance to flow of artificial CSF within the shunt system. The increase in resistance appears to be related to the duration of implantation and the length of the catheter and inversely related to the diameter of the catheter. This increase in resistance may be related to sterile shunt malfunction. The addition of straight connectors is associated with a significant increase in resistance in comparison with catheters without connectors (p = 0.005).

Analysis of adjacent segment degeneration with laminectomy above a fused lumbar segment

Although recent data suggests that lumbar fusion with decompression contributes to some marginal acceleration of adjacent segment degeneration (ASD), few studies have evaluated whether it is safe to perform a laminectomy above a fused segment. This study investigates the hypothesis that laminectomy above a fused lumbar segment does not increase the incidence of ASD, and assesses the benefits and risks of performing a laminectomy above a lumbar fusion. A retrospective review of 171 patients who underwent decompression and instrumented fusion of the lumbar spine was performed to analyze the association between ASD and laminectomy above the fused lumbar segment. Patients were divided into two groups - one group with instrumented fusion alone and the other group with instrumented fusion plus laminectomy above the fused segment. Of the 171 patients, 34 underwent additional decompressive laminectomy above the fused segment. There was a significant increase in ASD incidence as well as progression of ASD grade in both groups. There was no significant increase in ASD in patients with decompressive laminectomy above the fused lumbar segment compared to patients with laminectomy limited to the fused segment. This retrospective review of 171 patients who underwent decompression and instrumented fusion with follow-up radiographs demonstrates that laminectomy decompression above a fused segment does not significantly increase radiographic ASD. There is, however, a significant increase in ASD over time, which was observed throughout the entire cohort likely representing a natural progression of lumbar spondylosis above the fusion segment.

Rectal sphincter pressure monitoring device

A silicone, dual cuffed catheter designed for the control of nasal hemorrhage was used for rectal sphincter pressure monitoring. Patients with lipomyelomeningocele and tethered spinal cord were monitored during their operative procedures to aid in distinguishing sacral nerve roots from other tissues. Stimulation of sacral nerve roots was done with a disposable nerve stimulator. The use of a catheter with two balloons helps to keep the outer balloon placed against the rectal sphincter.

Effect of Protein Concentration on the Flow of Cerebrospinal Fluid Through Shunt Tubing

BACKGROUND Protein levels in cerebrospinal fluid (CSF) are commonly thought to be related to sterile shunt malfunction. OBJECTIVE To investigate the relationship between protein concentration and flow through CSF shunt tubing and a shunt valve. METHODS New and explanted shunt catheters were tested with and without a shunt valve attached at various protein concentrations. The protein concentrations used were 0.5, 2, 5, and 10 g/L. A flask with artificial CSF attached to the proximal end provided flow. The flow was allowed to stabilize over 1 hour, and then the change in pressure between the proximal and distal end of the catheter was measured and recorded. The resistance to flow was calculated for new and explanted catheters for adult shunt systems, as well as with the addition of a programmable siphon control valve. The resistance was examined after the addition of various protein concentrations to a normal CSF solution. RESULTS Both new and explanted catheters exhibited a decrease in the resistance to flow with higher concentrations of protein. CONCLUSION In our laboratory setting, there was decreased resistance of adult CSF shunt catheters with and without a valve as the concentration of protein in the CSF increased. The decrease in the resistance of CSF shunt catheters with the addition of protein to the CSF may be related to the lowering of surface tension. This is the first study to examine the effects of varying protein concentrations across different lengths of shunt tubing for both new and explanted catheters.

Cerebrospinal fluid shunt valve fracture with separation: Report of three cases

Three cases of shunt valve fracture with separation are reported. Fracture with separation of the shunt valve of a cerebrospinal fluid shunt is an infrequent occurrence. Because a portion of the shunt valve is radiolucent on a shunt survey radiograph, this problem is easily overlooked if it occurs. The diagnosis can be made by comparing old and new shunt survey radiographs and noting the increased distance between radiopaque portions of the shunt on the new X-ray films.