Biomedical subjects
Johnny B Delashaw
Publications and source records attributed to Johnny B Delashaw.
Indications for cerebrospinal fluid drainage and avoidance of complications.
An understanding of normal CSF physiology is a prerequisite to treating problems such as CSF fistulae and pseudomeningoceles. CSF diversion techniques fall into two categories, external and internal. External lumbar drainage is useful when temporary CSF diversion is necessary (eg, in cases necessitating manipulation and retraction of the brain to gain access to deep lesions) and in treating otorrhea or rhinorrhea following traumatic or iatrogenic insults to the cranial base. Drawbacks include insertion discomfort and limited duration of therapy.LP and VP shunts came into widespread use in the 1970s, and both systems share risks of bowel perforation, obstruction, over drainage and wound-related complications. In addition, VP shunts add the risks of intracerebral hematoma and ventriculitis. New valve technology has made it possible to alter the volume drained, thus alleviating problems of over-and under drainage.
Radial forearm free tissue transfer in the management of persistent cerebrospinal fluid leaks.
OBJECTIVE: Cerebrospinal fluid (CSF) leaks can occur after head trauma or skull base surgery. Persistent or spontaneous leaks should be repaired, since they put patients at risk for serious intracranial complications. Although numerous repair methods have been successful, the occasional patient develops a persistent leak. We describe our experience with free tissue transfer for repair of recalcitrant CSF leaks. STUDY DESIGN: Retrospective chart review of patients undergoing free tissue transfer for repair of a CSF leak between November 1995 and October 2004. Setting was an academic, tertiary care referral center. METHODS: Twelve patients with persistent CSF leak were studied. Eleven of 12 patients had undergone a previous repair attempt ranging from endoscopic repair with fat graft to craniotomy and primary repair of the dural defect. All patients underwent radial forearm free tissue transfer. RESULTS: There were six female and six male patients. Average age was 52.7 years (range, 22-80 y). The most common presenting complaints were intracranial abscess, recurrent meningitis, or pneumocephalus (n=9) and CSF otorrhea or rhinorrhea (n=8). Cause was head trauma (n=6), prior surgery (n=4), cholesteatoma (n=1), or meningoencephalocele (n=1). Eleven of 12 patients failed prior procedures (range, 0-6 procedures; mean, 1.9). Ten flaps were placed in the anterior skull base and two were in the middle or posterior skull base. Radial forearm free tissue transfer resulted in sustained resolution of CSF leakage in all 12 patients. CONCLUSIONS: Free tissue transfer is an efficacious option in the repair of recalcitrant CSF leaks.
Modified osteoplastic orbitozygomatic craniotomy. Technical note.
The authors report on a surgical technique involving a one-piece osteoplastic bone flap, which incorporates the frontal, temporal, and lateral portions of the orbital rim as a technically simpler alternative to the standard orbitozygomatic (OZ) craniotomy. The orbital rim component extends just laterally from the supraorbital foramen/notch to the frontozygomatic suture. This craniotomy obviates the need for removing the zygoma and has evolved from the authors' experience in more than 200 patients with a variety of pathological lesions, both vascular and tumorous. The osteoplastic aspect of this technique was initially evaluated in 14 cadaveric sites in seven heads dissected prior to implementing this procedure clinically. The osteoplastic bone flap minimally obstructs the surgical view and provides all the advantages of a standard OZ craniotomy. Temporalis muscle atrophy leading to temporal hollowing is avoided, a bone union to the calvaria is improved, and the possibility of bone infection is decreased. The osteoplastic component of the technique adds to the improved long-term cosmesis and warrants active consideration in the art of neurosurgery.
Extradural anterior clinoidectomy. Technical note.
The anterior clinoid process (ACP), located on the skull base, is a relatively small structure, although its removal provides enormous gain in facilitating the management of lesions--either tumors or aneurysms--in the paraclinoid region and upper basilar artery. The extensive surgical field gained contributes to safer exposure of the neurovascular elements in the vicinity while avoiding excessive and hazardous retraction of the brain. In this report the authors present a technically simpler avenue for performing an extradural anterior clinoidectomy after reviewing the anatomy of the ACP and its anatomical variations. Additionally, the original Dolenc procedure and its subseqtient derivatives are compared and contrasted to the authors' simpler and less laborious technique. Different clinical situations in which to use the procedure are described based on the authors' experience from 60 cases (40 aneurysm cases and 20 tumor cases) during a 4-year period.
Supraorbital craniotomy for parasellar lesions. Technical note.
The authors present a modification to a previously reported supraorbital craniotomy procedure that is smaller, simpler, safe, and cosmetically pleasing. Minimal brain retraction is used without compromising the surgical exposure of the orbital roof, floor of the anterior fossa, and the parasellar region to treat tumoral lesions that are located medial to the ipsilateral optic nerve as well as aneurysms of the anterior communicating artery.
Hearing preservation with the transcrusal approach to the petroclival region.
OBJECTIVE: We studied the hearing results and outcomes after transcrusal craniotomy. STUDY DESIGN: We conducted a retrospective review. SETTING: This study was conducted at a tertiary care hospital. PATIENTS: We studied 10 consecutive patients, including two men and eight women, who underwent transcrusal craniotomy for petroclival masses or tumors. INTERVENTION: The intervention consisted of therapeutic removal of petroclival meningioma. MAIN OUTCOME MEASURE: The main outcome measure of this study was hearing preservation as measured by standard audiogram. RESULTS: There were six meningiomas, one eighth nerve schwannoma, one fifth nerve schwannoma, one chordoma, and one midbasilar artery aneurysm. Postoperative hearing was measured according to the AAOHNS criteria. Complications and further therapies were recorded. Postoperative hearing was measured in eight. The cochlear nerve was severed in one patient. One was unavailable for follow up. Eight patients retained hearing at or near preoperative levels, seven with SRT within 10 dB and speech discrimination within 10% of preoperative levels. Four patients presented with trigeminal symptoms, one with third nerve palsy and two with facial weakness. Postoperative deficits included fourth, sixth, seventh, and eighth nerve palsies in three patients. Complications included one wound infection, two cerebrospinal fluid leak, and two cases of meningitis, both of which were sterile. There were secondary procedures in five patients-three radiosurgery, two shunts, one tracheotomy, and one g-tube. CONCLUSIONS: Transcrusal craniotomy is a safe and effective approach to the petroclival region. Excellent hearing results can be expected with this technique.
Extended middle fossa approach: quantitative analysis of petroclival exposure and surgical freedom as a function of successive temporal bone removal by using frameless stereotaxy.
OBJECT: Conventional wisdom regarding skull base surgery says that more extensive bone removal equals greater exposure. Few researchers have quantitatively examined this assertion, however. In this study the authors used a frameless stereotactic system to measure quantitatively the area of petroclival exposure and surgical freedom for manipulation of instruments with successive steps of temporal bone removal. METHODS: With the aid of high-power magnification and a high-speed drill, 12 cadaveric specimens were dissected in four predetermined, successive bone removal steps: 1) removal of the Kawase triangle; 2) removal of the Glasscock triangle; 3) removal of the cochlea together with skeletonization of the anterior internal auditory canal; and 4) inferior displacement of the zygoma. Step 1 offered 62 +/- 43 mm2 of exposed petroclival area, with 84 +/- 69 mm2 of surgical freedom; Step 2, 61 +/- 22 and 76 +/- 58 mm2; Step 3, 128 +/- 47 and 109 +/- 87 mm2; and Step 4, 135 +/- 38 and 102 +/- 69 mm2, respectively. CONCLUSIONS: The middle fossa approach provided a means surgically to expose the petroclival area. When examined quantitatively by using a frameless stereotactic device, the authors determined that the removal of the cochlea and skeletonization of the anterior internal auditory canal (Step 3) provided the most significant increase in both exposure and surgical freedom. Removal of the zygoma improved neither exposure nor surgical freedom.
Choroid plexus papilloma of the third ventricle in the fetus. Case illustration.
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Incidence, etiology, and management of cerebrospinal fluid leaks following trans-sphenoidal surgery.
OBJECTIVES/HYPOTHESIS: The incidence of cerebrospinal fluid (CSF) leak following trans-sphenoidal surgery ranges from 0.5% to 15.0%. Factors predicting which patients are likely to develop postoperative leaks and optimal management of these patients are poorly defined. The objective was to determine 1) the incidence of CSF leak following trans-sphenoidal surgery; 2) demographic or intraoperative factors associated with postoperative leaks; 3) techniques and efficacy of postoperative leak management at Oregon Health and Science University, (Portland, OR). STUDY DESIGN: Retrospective chart review. METHODS: Two hundred thirty-five trans-sphenoidal surgeries were performed on 216 patients between 1994 and 2001. Follow-up data were available for 217 operations (92.3%) performed on 202 patients (93.5%). RESULTS: Postoperative CSF leaks occurred in 6.0% (13 of 217) of patients. Leaks were more common in the setting of revision surgery versus primary surgery (14.6% vs. 4.0%, P =.0096), nonadenomatous disease versus pituitary adenoma (15.8% vs. 5.1%, P =.059), or if an intraoperative leak occurred (12.7% vs. 2.7%, P =.004). However, on multivariate analysis, only the presence of intraoperative leak (P =.008) and nonadenomatous disease (P =.047) were found to be independently associated with postoperative CSF leak. Size of adenoma was not associated with occurrence of postoperative CSF leak (6.4% for microadenoma vs. 4.2% for macroadenoma) on both univariate and multivariate analysis. There were 13 postoperative CSF leaks: 2 resolved with lumbar drainage and 11 required operative management (three required multiple procedures). Of the three patients who required multiple operations, two had hospital courses complicated by meningitis and postinfectious hydrocephalus and ultimately required ventriculoperitoneal shunts. Endoscopic re-exploration was successful in 87.5% (7 of 8) of cases. CONCLUSIONS: Cerebrospinal fluid leaks following trans-sphenoidal surgery occurred in 6.0% of cases. Nonadenomatous disease and presence of an intraoperative leak were independent predictors of a postoperative leak. Endoscopic re-exploration combined with packing was an effective technique in managing uncomplicated postoperative leaks. In the setting of meningitis and postinfectious hydrocephalus, more invasive techniques such as ventriculoperitoneal shunt may be necessary.