Douglas E. Anderson

Optimal clip application and intraoperative angiography for intracranial aneurysms

BACKGROUND The actual incidence of residual aneurysm after clipping is unknown. The natural history of residual aneurysm can be regrowth and hemorrhage. Intraoperative angiography offers a cost-effective, safe interdiction to the problem of residual aneurysm and parent vessel stenosis. METHODS/RESULTS Forty consecutive patients harboring 54 aneurysms underwent 42 operative procedures to clip 52 aneurysms, during which 220 intraoperative angiographic runs were performed. Ninety-three percent of the procedures were performed on patients with acute subarachnoid hemorrhage. There were 4 giant (>2.5 cm, 4/52 = 8%, all anterior circulation), 21 large (1.0-2.5 cm, 21/52 = 40%, 16/ 21 = 76% anterior circulation, 6/21 = 28% posterior circulation), and 27 small (<1.0 cm, 27/52-52%, 22/27 = 81% anterior circulation, 5/27 = 18% posterior circulation) aneurysms. Intraoperative angiography led to clip adjustment in 18/52 = 34% of aneurysms (4/18 = 22% for parent artery stenosis, 8/18 = 44% for residual aneurysm and 6/18 = 33% for both). Of the 18 adjustments made, 16 = 88% were made on giant or large aneurysms and two were small (one was a complex anterior communicating and one was a vertebral junction aneurysm). Follow-up angiography was performed on 26/42 = 62% of operative cases. Postoperative angiography confirmed intraoperative angiography in all cases. Two complications occurred during 220 angiographic runs: one embolic stroke and one incident of equipment failure. CONCLUSION A grading scale was applied to test the relationship between anatomical site and size as they relate to the necessity for clip adjustment for complete aneurysm obliteration and/or parent artery compromise. Significance was related to site (basilar bifurcation, anterior communicating, middle cerebral bifurcation, and ophthalmic) and size (>1.0 cm), both as independent and codependent variables. An analysis of the cost-effectiveness of intraoperative angiography was demonstrated.

Successful treatment of chronic paroxysmal hemicrania with posterior hypothalamic stimulation: technical case report.

OBJECTIVEChronic paroxysmal hemicrania (CPH) is a rare, unilateral primary headache syndrome. Recent studies suggest hypothalamic dysfunction as the likely cause of CPH. Therapeutic response to deep brain stimulation of the hypothalamus has been observed in the treatment of related trigeminal autonomic cephalgias. We explored the therapeutic effectiveness of posterior hypothalamic stimulation for the treatment of CPH in a patient intolerant of medical management. CLINICAL PRESENTATIONA 43-year-old woman with CPH reported acute onset of lancinating, unilateral headache pain focused about the right orbit. These debilitating headaches were accompanied by ipsilateral nasal congestion, conjunctival injection, tearing, and ptosis lasting minutes before resolving spontaneously. The patient exhausted attempts at medical management. TECHNIQUEA deep brain stimulator microelectrode was placed under stereotactic guidance. The posterior hypothalamic target was 3 mm posterior, 5 mm inferior, and 2 mm ipsilateral to the midcommissural point. The electrode was connected to a standard pulse generator and set to final amplitude of 1.5 V, a pulse width of 60 microseconds, and a frequency of 185 Hz. CONCLUSIONThe patients headache symptoms were durably alleviated with intraoperative activation. No complications were observed. This preliminary success suggests a role for posterior hypothalamic stimulation as a safe and effective treatment in patients with medically refractory CPH. As a therapeutic incremental innovation, this off-label use of technology for symptomatic therapy contributes to results of studies that support a central pathophysiological role for hypothalamic dysfunction in headaches classified among the trigeminal autonomic cephalgias.

Refinements using free-tissue transfer for complex cranial base reconstruction.

Resection of skull base tumors may sometimes result in massive extirpation defects that are not amenable to local tissue closure. Closure of large basicranial defects can be performed with either a myocutaneous, a deepithelialized myocutaneous, or a simple muscle free flap designed from the ample rectus abdominis vascular territory. This free-tissue donor site has abundant and reliable well-vascularized tissue that can easily be customized to seal these tenuous areas. The rectus abdominis muscle and its vascularized territory were used in 18 of 19 consecutive patients at our center to close basicranial ablation defects. Of these, 6 were rectus abdominis muscle flaps, 5 were myocutaneous rectus abdominis flaps, and 7 were deepithelialized rectus abdominis muscle flaps. All free flaps survived. The intracranial space was sealed successfully in all but one patient. This patient underwent reconstruction with a muscle free flap and had a postoperative cerebrospinal fluid leak. This complication could have been avoided by using a deepithelialized myocutaneous flap to obliterate the central dead space with the vascularized subcutaneous fat. Two patients experienced minor wound infections, and one had a subdural abscess that was fully contained by a free flap placed over the duraplasty. One patient had a donor-site hernia. There was no incidence of meningitis. Knowledge of the anatomy of the vascular territory of the deep inferior epigastric vessels can be used judiciously to secure three-dimensional reconstruction of the skull base. The donor site supplies ample tissue for reconstruction and allows individual tailoring for obliteration of geometrically complex extirpation defects in and around the cranial base without the need to reposition the patient. (Plast. Reconstr. Surg. 92: 567, 1993.)

Cerebrospinal Fluid Fistula after Transtemporal Skull Base Surgery

OBJECTIVES: The purpose of this article is to outline our methods for the prevention and management of cerebrospinal fluid (CSF) leak after transtemporal skull base surgery. METHODS: A total of 589 patients underwent a variety of transtemporal surgical approaches for the extirpation of skull base tumors at our institution from July 1988 to October 1999. The medical records were retrospectively reviewed to identify the tumor histology, size, and location as well as the surgical approach, defect reconstruction technique, and the incidence of postoperative CSF leak. RESULTS: The risk of CSF fistulae was greatest in utilizing the restrosigmoid approach (8%) and least in those who underwent a translabyrinthine approach (4%). Tumor size had no bearing on the incidence of the CSF leak and the overall incidence of meningitis was 1.0%. CONCLUSION: The proper surgical technique will minimize the risk of CSF leak after transtemporal skull base surgery. Immediate management of CSF fistulae helped prevent meningitis in the majority of these patients.

Improved cerebral blood flow and CO2 reactivity after microvascular anastomosis in patients at high risk for recurrent stroke.

The medical community has not yet identified cerebrovascular pathophysiological factors that distinguish patients at high risk for stroke or aid in selecting patients for microvascular cerebral bypass. In this study, we describe the courses of 13 patients, all of whom suffered recurrent episodes of transient cerebral ischemia after previous cerebral infarction. These patients underwent regional cerebral blood flow studies using xenon inhalation with a CO2 challenge before and at various times after extracerebral-to-intracerebral microvascular anastomosis. Collateral circulation was assessed in all patients before surgery using four-vessel cerebral angiography. Patients were followed for a mean of 30 months (range, 1-7 yr) after the anastomosis. Measurements of mean cortical cerebral blood flow, as measured using the initial Slope Index, and CO2 cerebrovascular reactivity of these 13 patients were compared with those in a group of 20 patients designed as controls. Hemispheric cortical blood flow was significantly depressed in these patients before surgery compared with those in the control group (P less than 0.05). After the bypass, the mean resting Initial Slope Index in these patients increased 14% (P = 0.0005). Cerebral blood flow both before and after CO2 inhalation improved significantly in these patients after surgery (P = 0.001). Detectors bordering computed tomographic or magnetic resonance image documented infarctions, identified as peri-infarct regions, and demonstrated significant mean increases in both cerebral blood flow (38.8-43.2 ml/min/100 g, P = 0.05) and CO2 cerebrovascular reactivity in these patients after bypass (1.71 + 1.91% to 4.00 + 2.38% change Initial Slope Index/mm Hg CO2, P = 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

From prefrontal leukotomy to deep brain stimulation: the historical transformation of psychosurgery and the emergence of neuroethics

The history of psychosurgery is described and analyzed. This historical perspective largely begins with analysis of the work of Egas Moniz in the development of the leukotomy, and follows the rise and fall of its popularity in the 1900s. The reemergence of psychosurgical procedures and the development of new therapeutic technologies such as vagus nerve stimulation and deep brain stimulation are discussed. In addition, an introduction to the field of neuroethics is provided, given its importance in any discussion about surgical therapy for psychiatric patients.

The clinical significance and optimal timing of postoperative computed tomography following cranial surgery

OBJECT This study was conducted to evaluate the value of postoperative CT scans in determining the probability of return to the operating room (OR) and the optimal time to obtain such scans to determine the effects of surgery. METHODS Between January and December 2006 (12 months), all postoperative head CT scans obtained for 3 individual surgeons were reviewed. Scans were divided into 3 groups, which were determined by the preference of each surgeon: Group A (early scans-scheduled between 0 and 7 hours); Group B (delayed scans-scheduled between 8 and 24 hours); and Group C (urgent scans-ordered because of a new neurological deficit). The initial scans were reviewed and analyzed in 2 different fashions. The first was to analyze the efficacy of the scans in predicting return to the OR. The second was to determine the optimal time for obtaining a scan. The second analysis was a review of serial postoperative scans for expected versus unexpected findings and changes in the acuity of these findings over time. RESULTS In 251 (74%) of 338 cases, the patients had postoperative head CT scans within 24 hours of surgery. Analysis 1 determined the percent of patients returning to the OR for emergency treatment based on postoperative scans: Group A (early)-133 patients, with 0% returning to the OR; Group B (delayed)-108 patients, with 0% returning to the OR; and Group C (urgent)-10 patients, with 30% returning to the OR (p < 0.05). Analysis 2 determined the optimal timing of postoperative scans and changes in scan acuity: Group A (early scan) had an 11% incidence of change in acuity on subsequent scans. Group B (delayed scan) had a 3% incidence of change in acuity on follow-up scans (p < 0.05). CONCLUSIONS Routine postoperative scans at 0-7 hours or at 8-24 hours are not predictive of return to the OR, whereas patients with a new neurological deficit in the postoperative period have a 30% chance of emergency reoperation based on CT scans. In addition, early postoperative scans (0-7 hours) fail to predict CT changes, which might evolve over time and may influence postoperative medical management.

Perioperative and long-term operative outcomes after surgery for trigeminal neuralgia: microvascular decompression vs percutaneous balloon ablation

ObjectivesNumerous medical and surgical therapies have been utilized to treat the symptoms of trigeminal neuralgia (TN). This retrospective study compares patients undergoing either microvascular decompression or balloon ablation of the trigeminal ganglion and determines which produces the best long-term outcomes.MethodsA 10-year retrospective chart review was performed on patients who underwent microvascular decompression (MVD) or percutaneous balloon ablation (BA) surgery for TN. Demographic data, intraoperative variables, length of hospitalization and symptom improvement were assessed along with complications and recurrences of symptoms after surgery. Appropriate statistical comparisons were utilized to assess differences between the two surgical techniques.ResultsMVD patients were younger but were otherwise similar to BA patients. Intraoperatively, twice as many BA patients developed bradycardia compared to MVD patients. 75% of BA patients with bradycardia had an improvement of symptoms. Hospital stay was shorter in BA patients but overall improvement of symptoms was better with MVD. Postoperative complication rates were similar (21% vs 26%) between the BA and MVD groups.DiscussionMVD produced better overall outcomes compared to BA and may be the procedure of choice for surgery to treat TN.

What's New in the Diagnosis and Treatment of Peripheral Nerve Entrapment Neuropathies

Entrapment neuropathies can be common conditions with the potential to cause significant disability. Correct diagnosis is essential for proper management. This article is a review of recent developments related to diagnosis and treatment of various common and uncommon nerve entrapment disorders. When combined with classical peripheral nerve examination techniques, innovations in imaging modalities have led to more reliable diagnoses. Moreover, innovations in conservative and surgical techniques have been controversial as to their effects on patient outcome, but randomized controlled trials have provided important information regarding common operative techniques. Treatment strategies for painful peripheral neuropathies are also reviewed.

Surgical management of facial neuromas: lessons learned.

Objective: Primary tumors of the facial nerve are rare, representing 1% of all intrapetrous lesions. We analyzed the management and surgical outcomes of 16 patients with multisegment facial neuromas treated at our institution during a 16-year period. Study Design: A retrospective chart review. Setting: Tertiary referral center. Patients: All patients included in the study had surgical management of their facial neuroma. There were 9 women and 7 men. The mean age was 46 years, with a mean follow-up period of 3 years. Intervention: Surgical excision (n = 15) or decompression (n = 1) of facial neuroma. Main Outcome Measures: Tumor location, presenting symptoms, hearing outcomes, and facial function. Results: Thirteen (81%) patients had facial paresis as their presenting symptom. Unilateral hearing loss was present in 9 (56%) patients. Most tumors (n = 15) involved multiple segments of the facial nerve and ranged in size from 1.5 to 7 cm. Fifteen (94%) patients had the tumor completely excised, and 1 (6%) patient underwent needle decompression of the cystic component of the tumor. The geniculate ganglion was the most commonly involved (11 patients, 69%) segment of the nerve, followed by the labyrinthine and tympanic segments. Despite multiple types of reconstructive options used, the best recovery of facial function was a House-Brackmann Grade III in 12 patients. Conclusion: Treatment of facial neuromas depends on the extent of tumor, degree of facial paresis, and hearing function. We advocate complete resection of tumor when facial palsy exists. Patients with normal facial function and hearing may be advised on a more conservative treatment option such as radiologic observation, drainage of any cystic component of the tumor for histologic diagnosis, and/or bony decompression of the tumor.