Joel D. MacDonald

Extensive experience with dural sinus thrombosis

OBJECTIVEDural sinus thrombosis (DST) is an uncommon cause of stroke. The safest and most effective therapy for DST has not been conclusively identified. METHODSA retrospective chart review of data for 31 patients who were treated for DST at our institution between 1992 and 2001 was performed. Four treatment strategies were identified, i.e., 1) medical observation only, 2) systemic anticoagulation (AC) therapy with heparin, 3) endovascular chemical thrombolysis with urokinase or tissue plasminogen activator and concurrent systemic AC therapy, and 4) mechanical endovascular clot thrombolysis with concurrent systemic AC therapy. Complications and clinical outcomes were assessed for each group. RESULTSPatients treated solely with medical observation fared the worst; four of five patients experienced intracranial hemorrhagic complications, and only two of five exhibited clinical improvement. Patients who received systemic AC therapy experienced no hemorrhagic complications, even when pretreatment hemorrhage was present; 75% (six of eight patients) exhibited improvement with AC therapy alone. Chemical thrombolysis was very effective in restoring sinus patency (90% of patients); however, 30% of patients (3 of 10 patients) experienced hemorrhagic complications. Sixty percent of patients (6 of 10 patients) who underwent chemical thrombolysis exhibited clinical improvement. Patients who underwent mechanical thrombectomies demonstrated a low hemorrhagic complication rate, and most (88%) made good recoveries. CONCLUSIONTherapy directed at the underlying clot in DST must begin without delay. Our results suggest that supportive medical management of DST, without therapy directed at the clot or clotting process, is not effective. Systemic AC therapy, even in the presence of intracerebral hemorrhage, seems to be safe. Heparin can be safely titrated to yield partial thromboplastin times of 60 to 70 seconds. Chemical clot thrombolysis is efficacious in opening occluded sinuses but may cause intracranial hemorrhage. We currently recommend either systemic AC therapy or systemic AC therapy in conjunction with mechanical clot thrombectomy as a safe effective treatment for DST.

2016 Infectious Diseases Society of America (IDSA) Clinical Practice Guideline for the Treatment of Coccidioidomycosis

It is important to realize that guidelines cannot always account for individual variation among patients. They are not intended to supplant physician judgment with respect to particular patients or special clinical situations. Infectious Diseases Society of America considers adherence to these guidelines to be voluntary, with the ultimate determination regarding their application to be made by the physician in the light of each patients individual circumstances.Coccidioidomycosis, also known as San Joaquin Valley fever, is a systemic infection endemic to parts of the southwestern United States and elsewhere in the Western Hemisphere. Residence in and recent travel to these areas are critical elements for the accurate recognition of patients who develop this infection. In this practice guideline, we have organized our recommendations to address actionable questions concerning the entire spectrum of clinical syndromes. These can range from initial pulmonary infection, which eventually resolves whether or not antifungal therapy is administered, to a variety of pulmonary and extrapulmonary complications. Additional recommendations address management of coccidioidomycosis occurring for special at-risk populations. Finally, preemptive management strategies are outlined in certain at-risk populations and after unintentional laboratory exposure.

Cervical catheter tip placement for intrathecal baclofen administration.

OBJECTIVE:Intrathecal baclofen can reduce congenital and posttraumatic spasticity. Traditionally, the catheter tip for baclofen delivery is placed in a low thoracic position, which can result in a lumbar-to-cisternal cerebrospinal fluid baclofen concentration gradient. We investigated whether more rostral catheter placement was technically feasible, safe, and able to control upper extremity spasticity. METHODS:The records of 48 patients with a baclofen pump were reviewed retrospectively to evaluate the safety and efficacy of cervically placed intrathecal catheters for baclofen administration. Twenty-three patients had a catheter located in a cervical position and 25 had a catheter in a thoracic position (control group). Complications, including baclofen overdose, mechanical failures, and infections, were noted. Pre- and postoperative Ashworth scores were determined by a physical therapist using a standardized protocol. RESULTS:The mean duration of the follow-up period was 10 months. The groups were not significantly different in patient age, baclofen dose, or duration of follow-up, but differed somewhat in the causes of spasticity. For patients with a cervical catheter tip position, upper extremity Ashworth scores decreased significantly from 4.0 ± 0.8 (standard deviation) preoperatively to 3.0 ± 0.9 postoperatively (P = 0.003). In both groups, lower extremity spasticity was significantly reduced. Postoperatively, one patient with a cervical catheter developed aspiration pneumonia, possibly because of sedation. Other complications included hardware infections, mechanical malfunctions, and pseudomeningoceles. CONCLUSION:In this series, placement of intrathecal baclofen catheters in the cervical region resulted in equal control of spasticity in the upper and lower extremities and did not increase complications related to the catheter position.

Revision of vagal nerve stimulator electrodes: technical approach

SummaryBackground. As the number of implanted vagal nerve stimulators grows, the need for removal or revision of the devices will become more frequent. Our purpose was to demonstrate the feasibility of complete removal of the vagal nerve stimulator electrode using microsurgical technique. Methods. Operative databases at the University of Utah (1995 through 2002), Westchester Medical Center (1995 through 2001), and University of Arizona Health Sciences Center (1995 through 1999) were retrospectively reviewed. Patients who had undergone removal or revision of a previously placed vagal nerve stimulator electrode were identified. Patients who had a vagal nerve stimulator device removed but had the lead trimmed and incompletely removed were excluded. Findings. Seven patients underwent complete removal of the lead. Microsurgical dissection allowed removal of the helical electrode from the vagus nerve without apparent physiological consequences. Four patients had a new electrode placed just proximal to the original lead site. The operative procedure required an additional 30 minutes to complete compared with initial device placement. The four patients who underwent replacement of the electrode demonstrated normal device function and lead resistance at the time of postoperative follow-up. Each experienced a return to prior stimulation response and seizure control. Conclusions. This series suggests that the electrode can be removed from the vagus nerve and repositioned without significant consequence in most cases.

The History of Ventriculoscopy: Where Do We Go from Here?

With the availability of better endoscopes, improved lighting and increased instrumentation, the use of ventriculoscopy and ventriculostomy in the management of hydrocephalus is becoming increasingly more common. Neurosurgeons recognized the potential for endoscopic surgery early in this century, but were frustrated in many of their attempts at treatment due to the poor quality of the instruments available. Nevertheless, much progress has been made, and the stage was set for better results with modern instrument design. This paper reviews the history of endoscopes in neurosurgery and ponders the direction these instruments will take us in the near future.

Infusion of intrathecal baclofen for acute withdrawal : Technical note

Acute baclofen withdrawal syndrome is a life-threatening situation that demands early recognition and urgent treatment. The current therapy of choice for this syndrome is administration of intravenous benzodiazepines, propofol, and chemical paralytic drugs until the intrathecal system can be restored. The authors present a novel technique for administering baclofen intrathecally using a lumbar drain and a standard patient-controlled analgesia pump (in continuous infusion mode). In one case, this method was used to wean the patient from high-dose intrathecal baclofen treatment. In a second case, this method was used as a temporizing measure until the indwelling pump system could be repaired. In both cases, the patients recovered to their neurological baseline level, and lasting consequences of serious withdrawal were avoided.

Self-assessment in Neurological Surgery: The SANS Wired White Paper

OBJECTIVE:Periodic self-assessment is an important component of postgraduate medical education and certification. The Self-assessment in Neurological Surgery (SANS) examination has a history of usefulness for neurosurgical written and oral board examination preparation. The SANS Wired test represents a recreation of the original SANS test using an Internet-based platform. Advanced functionality and contemporary content have been added to meet the increasing requirements for demonstration of lifelong learning and self-assessment as part of the Maintenance of Certification (MOC) process. METHODS:A needs assessment was performed before the development of SANS Wired. Postexamination surveys for users obtaining continuing medical education credit were analyzed for user satisfaction with the platform and content. Test-item performance metrics were analyzed based on first-attempt responses. The economic value of SANS Wired as a component of the mandatory MOC process was evaluated. RESULTS:The needs assessment identified a deficiency of available content and mechanisms for neurosurgery-specific self-assessment. As of October 15, 2005, a total of 588 individuals had subscribed to SANS Wired (28 institutional licenses accounted for 229 users). Eighty-eight post-test surveys were analyzed for user satisfaction. Ninety-four percent of responses indicated that learning objectives had been met. Initial performance metrics show an average point-biserial discrimination index of +0.18 for all test items. CONCLUSION:The SANS Wired system seems to be an effective platform for neurosurgical self-assessment and is acceptable to users. The system satisfies, in part, two of the four required components of MOC, namely, periodic self-assessment and demonstration of cognitive expertise. It is endorsed by the American Board of Neurological Surgeons for MOC.

Surgical approaches for resection of vestibular schwannomas: translabyrinthine, retrosigmoid, and middle fossa approaches

Surgical removal remains one of the key treatment modalities for vestibular schwannomas. A team approach between a neurotologist and a neurosurgeon offers the patient the expertise of both specialties and maximizes the chances for an optimal outcome. Vestibular schwannomas can typically be resected through 1 of 3 main surgical approaches: the translabyrinthine, the retrosigmoid, or the middle fossa approaches. In this report and videos, the authors describe and illustrate the indications and surgical techniques for the removal of these tumors.

Examination of ELN as a Candidate Gene in the Utah Intracranial Aneurysm Pedigrees

Background and Purpose— A study of intracranial aneurysm (IA) sibpairs suggested association of an ELN haplotype with IA risk. Subsequent linkage analysis of the ELN region on chromosome 7q11 in high-risk Utah IA pedigrees significantly confirmed linkage between IA and the ELN region. Methods— We have investigated the ELN gene as a potential candidate gene for IA in Utah pedigrees. One IA case from each pedigree, who shared an ELN region haplotype segregating in the pedigree, was screened for mutation. The promoter region, 34 exons, and the 3′UTR (UnTranslated Region) of the ELN gene were screened for variants using DHPLC. Results— Variants were observed in the promoter region, exons 4 and 6, and the 3′UTR. Variants in exon 6 and in one 3′UTR position were unique to Utah. The remaining variants were absent in the controls. There was no evidence for segregation of the ELN variants found in IA cases with the hypothesized chromosome 7 haplotypes segregating in pedigrees. Conclusion— Our analysis does not support ELN as the gene responsible for familial IA in the linked Utah IA pedigrees.

The skin bleeding time test as a predictor of brain bleeding time in a rat model

Previous studies have indicated that the skin bleeding time test does not accurately reflect visceral bleeding time (BT). The present study examines the predictive value of the skin bleeding time for brain bleeding tendency. Sixteen Sprague-Dawley rats were divided into equal groups. The first group (controls) underwent standardized skin and brain bleeding time tests under general anesthesia. Mean skin BT was found to be 168.8 sec with a standard deviation of +/- 20.8 sec. Mean brain BT was found to be 172.5 sec with a standard deviation of +/- 19.6 sec. The second group was given 23.2 mg/kg of aspirin per day for five days prior to skin and brain BT testing. Mean skin BT in this group was 315 seconds with a standard deviation of +/- 72.2 sec which proved to be significantly different from the control skin BT (P = 0.0005). Brain BT in the aspirin treated group was 155.6 sec with a standard deviation of +/- 22.6 sec. Brain BT in both control and aspirin treated groups was not significantly different (P = 0.13). All animals were euthanized 30 minutes after brain BT and their brains harvested. One animal in the control group showed evidence of a small subcortical hemorrhage upon brain sectioning. Sectioned brains in the aspirin-treated group showed no evidence of subcortical hematoma. The results indicate that skin BT is prolonged by aspirin administration, but brain bleeding time is unaffected. Brain hemostasis is likely more dependent on intrinsic procoagulant than platelet function. The skin BT test may therefore be of little utility as a preoperative screening test for neurosurgical patients.