Current results of the surgical management of aneurysms of the basilar apex.

OBJECTIVE: To provide current information regarding the expected clinical outcomes and sources of morbidity and mortality in the modern surgical management of basilar apex aneurysms. METHOD: A retrospective review was conducted of 303 cases of such aneurysms that were treated surgically during 18 years at one institution. Postoperative angiography was performed in 81% of the cases. Clinical grading using the Glasgow Outcome Scale was conducted at the time of hospital discharge and for 91% of the surviving patients at 6 months after surgery. The preoperative parameters that were linked statistically to poor clinical outcome were identified through the use of single and multivariate analyses. RESULTS: More than 80% of the patients were operated on using some modification of the trans-sylvian exposure, and temporary arterial occlusion was used routinely. Good outcomes (Glasgow Outcome Scale scores of 4 or 5) were achieved in 76% of the patients at the time of discharge and in 81% of the patients at 6 months after surgery. There was no incidence of postoperative subarachnoid hemorrhage. Residual aneurysm was revealed by postoperative angiography in 6% of the cases. Factors found to be statistically linked to poor outcome included poor admission grade (Hunt and Hess Grades IV and V), patient age older than 65 years, computed tomographic demonstration of thick basal cistern clot, aneurysm size greater than 20 mm, and symptoms attributable to brain stem compression. CONCLUSION: Direct microsurgical repair of basilar apex aneurysms should result in good clinical outcomes in 80 to 85% of cases, with reliable prevention of subarachnoid bleeding and routine elimination/reduction of symptoms secondary to mass effect. Those patients who are at high risk for poor outcomes can be identified by the presence of certain clinical, radiographic, and demographic features before undergoing surgery and can be considered for alternative or adjunctive modes of therapy if long-term efficacy of such treatment is demonstrated.

Multidisciplinary approach to traumatic intracranial aneurysms secondary to shotgun and handgun wounds.

BACKGROUND: Traumatic intracranial aneurysms (TICAs) may develop following gunshot injuries to the head. Management of these lesions often combines various aspects of microneurosurgical and endovascular techniques to safely repair or obliterate vessel defects. METHODS: We reviewed our experience over the last 18 years and identified five cases of intracranial aneurysms following gunshot and handgun wounds that were treated surgically and/or endovascularly. RESULTS: All patients had successful obliteration of their lesions using a variety of therapeutic modalities aimed at preserving neurologic function while at the same time eliminating the aneurysm from the circulation. CONCLUSION: Both microneurosurgery and endovascular surgery have important roles to play in the management of TICAs. In some cases, both methods can be combined to eliminate lesions and maximize patient recovery in a safe, efficient, and effective fashion.

A founder mutation as a cause of cerebral cavernous malformation in Hispanic Americans.

BACKGROUND: Cerebral cavernous malformation is a vascular disease of the brain causing headaches, seizures, and cerebral hemorrhage. Familial and sporadic cases are recognized, and a gene causing familial disease has been mapped to chromosome 7. Hispanic Americans have a higher prevalence of cavernous malformation than do other ethnic groups, raising the possibility that affected persons in this population have inherited the same mutation from a common ancestor. METHODS: We compared the segregation of genetic markers and clinical cases of cavernous malformation in Hispanic-American kindreds with familial disease; we also compared the alleles for markers linked to cavernous malformation in patients with familial and sporadic cases. RESULTS: All kindreds with familial disease showed linkage of cavernous malformation to a short segment of chromosome 7 (odds supporting linkage, 4X10(10).1). Forty-seven affected members of 14 kindreds shared identical alleles for up to 15 markers linked to the cavernous-malformation gene, demonstrating that they had inherited the same mutation from a common ancestor. Ten patients with sporadic cases also shared these same alleles, indicating that they too had inherited the same mutation. Thirty-three asymptomatic carriers of the disease gene were identified, demonstrating the variability and age dependence of the development of symptoms and explaining the appearance of apparently sporadic cases. CONCLUSIONS: Virtually all cases of familial and sporadic cavernous malformation among Hispanic Americans of Mexican descent are due to the inheritance of the same mutation from a common ancestor.

External carotid-to-middle cerebral bypass in the treatment of complex internal carotid injury.

Patients with penetrating carotid injuries above C2 present special challenges to the cerebrovascular surgeon. A subgroup of patients may lack the vascular collaterals necessary to tolerate carotid sacrifice or prolonged ischemia during direct carotid repair. We present a technique of extracranial-intracranial (EC-IC) saphenous vein bypass in two patients with high cervical and skull base carotid injuries and poor vascular collaterals. This technique allows preservation of internal carotid flow during the proximal anastomosis. Interruption of cerebral blood flow is limited to the duration required for a distal intracranial anastomosis and is confined to the territory supplied by a single middle cerebral branch. The procedure eliminates systemic anticoagulation, includes trapping of the injured segment of the internal carotid artery, and restores a volume of flow similar to that of the internal carotid artery. It is a valuable adjunct in this specific population of patients with high carotid injuries who cannot tolerate even brief periods of temporary occlusion or in whom clinical urgency precludes an endovascular trial occlusion.

Orbital infarction syndrome after surgery for intracranial aneurysms.

BACKGROUND: Global orbital infarction results from ischemia of the intraocular and intraorbital structures due to hypoperfusion of the ophthalmic artery and its branches. PATIENTS: The authors describe six patients in whom acute proptosis, ophthalmoplegia, and blindness developed immediately after surgery for intracranial aneurysms. RESULTS: All patients underwent standard frontotemporal craniotomies to clip their aneurysms. In all patients, proptosis, ophthalmoplegia, and blindness developed in the immediate postoperative period; fundus abnormalities included retinal edema, retinal arteriolar narrowing and other vascular abnormalities, and pale optic disc swelling. Some patients had facial and corneal anesthesia. Ophthalmoplegia and facial anesthesia improved in most patients, but none regained any vision in the affected eye. CONCLUSION: Orbital infarction syndrome is a rare complication of neurosurgical procedures. Increased orbital pressure probably reduced ophthalmic artery and collateral arterial perfusion, resulting in ischemia of the intraocular and intraorbital structures. There may be multiple factors that compound the risk for orbital infarction, and patients with subarachnoid hemorrhage, increased intracranial pressure, anomalous arterial or venous circulation, or impaired orbital venous outflow seem particularly vulnerable.

Treatment of traumatic arterial vasospasm with intraarterial papaverine infusion.

We report a case of severe posttraumatic arterial vasospasm treated with repetitive intraarterial papaverine infusions. The salient features of the mechanism of action of papaverine are included.

An unusual transcranial Doppler waveform associated with vessel distortion in giant intracranial aneurysms.

Although the shapes of velocity waveforms obtained with transcranial Doppler examination can indicate such abnormalities as increased intracranial pressure and proximal arterial compromise, the significance of unusual waveform morphologies is often obscure. In this report, we describe four cases in which an unusual waveform morphology was obtained from vessels distorted and narrowed by intracranial masses. The appearance of this unusual morphology as an isolated signal within a transcranial Doppler examination should, therefore, suggest a structural deformation of the insonated vessel to those who interpret transcranial Doppler studies.

Surgery for paraclinoidal carotid artery aneurysms.

Aneurysms arising from the proximal carotid artery between the roof of the cavernous sinus and the origin of the posterior communicating artery pose conceptual and technical surgical problems with regard to acquisition of proximal control and safe intracranial exposure. Over the past 3 1/2 years, 89 patients with paraclinoidal aneurysms have been treated at the University of Texas Southwestern Medical Center. Thirty-nine (44%) of these patients presented with subarachnoid hemorrhage. A total of 149 aneurysms and six arteriovenous malformations have been identified in this patient group such that 38 (43%) of the patients suffered multiple vascular anomalies. Temporary artery occlusion has been employed during operation in 48 cases (54%), permanent carotid artery occlusion in four (4%), and hypothermic circulatory arrest in two (2%). Twenty-two patients harbored giant aneurysms, seven of which had ruptured. Outcome was considered good in 77 patients (86.5%), fair in eight (9%), and poor in three (3%); one patient died. This concentrated experience permitted a practical anatomical grouping of aneurysms into three types: carotid-ophthalmic artery aneurysms with a superior or superomedial projection (44 cases); superior hypophyseal aneurysms with a medial or inferomedial projection (26 cases); and proximal posterior carotid artery wall aneurysms projecting posteriorly or posterolaterally (19 cases). Despite the fact that paraclinoidal aneurysms often disobey the traditional teachings of aneurysm development, having no vessel of origin or clear hemodynamic cause, this practical grouping has allowed individualized and focused operative approaches unique to each aneurysm projection with good visual function and outcome in most patients.

Combined transsylvian-subtemporal exposure of cerebral aneurysms involving the basilar apex.

The surgical repair of cerebral aneurysms involving the apex of the basilar artery continues to undergo refinement and evolution. The inherent difficulty in accessing the basilar apex as well as the complexities of the microanatomy render this area a notoriously hazardous and technically challenging region in which to perform microsurgical clipping of cerebral aneurysms. Several operative approaches have been described and are constantly undergoing a state of evolution in the hopes of optimizing the exposure of the distal basilar artery and minimizing the inherent risks of surgery. The consistent decline in operative morbidity has paralleled improved understanding of the microvascular anatomy, both in this region and along the various corridors of approach. No single operative approach is universally superior, considering the wide variability of individual patient anatomy and vascular configurations. Each approach has strengths, weaknesses, and potential complications that must be considered in the though process of planning an operative attack on a basilar apex aneurysm. Intimate familiarity with the microvasculature and the microsurgical anatomy of the region is an imperative prerequisite for the application of any surgical approach to this region. This paper outlines a detailed review of the microsurgical anatomy that is pertinent to microsurgery of aneurysms in this region, and describes an approach referred to as the combined transsylvian-subtemporal approach. We have found this operative approach particularly useful in aneurysm surgery of the basilar apex but do not mean to imply that this single approach is suitable for all surgeons or all patients.(ABSTRACT TRUNCATED AT 250 WORDS)

The future. Prospects of innovative treatment of intracerebral hemorrhage.

Aggressive surgical as well as medical management strategies have had limited success with improving outcomes from spontaneous intracerebral hematomas. Future prospects of treatment will undoubtedly focus on less invasive, better tolerated procedures to remove hematomas in select patients. Some success has been achieved with a coupling of stereotactic technology, fibrinolytic agents, and mechanical devices, which can remove solid portions of hematoma through narrow probes. Newer technology also has involved laser endoscopic and small ultrasonic probes to facilitate morcellation and subsequent aspiration without the problems associated with a major intracranial procedure.

The transcranial Doppler appearance of acute carotid artery occlusion.

Transcranial Doppler ultrasound is a noninvasive technique of cerebral blood velocity measurement that is being increasingly used to detect untoward hemodynamic changes. In this report, we describe striking transcranial Doppler ultrasound changes occurring in 2 patients after cervical carotid artery occlusion that led to cerebral infarction. These changes consist of the sudden appearance of a Doppler signal of extremely low pulsatility and moderately high velocity in the middle cerebral artery distribution. In 1 patient, this signal was the first sign of carotid occlusion. We suggest that these transcranial Doppler ultrasound changes can provide an early warning of carotid artery compromise.

Ventriculopleural shunting used as a temporary diversion.

Due to the limited absorptive capacity of the pleural cavity, infants and young children are not generally ideal candidates for ventriculopleural shunts. We report using chest cavities as alternate for temporary diversion of CSF in a young child. Venous access to the cervical region could not be utilized because of scarring from previous procedures, while peritoneal access was contraindicated due to repeated pseudocyst formation. Pleural effusions were removed by thoracentesis when necessary, and the shunt catheter was changed to the opposite side of the chest when the effusions reaccumulated within one week. Utilizing the ventriculopleural shunts allowed us to temporize her non-communicating hydrocephalus for a period of one year, until a definitive CSF procedure by direct intracardiac placement of the distal catheter could be performed.

Central nervous system monitoring. What helps, what does not.

The ICU monitoring of CNS function can make a difference in the clinical outcome. No single technique addresses the multiple issues that arise in the ICU setting, especially for the polytrauma patient. Multimodality approaches combining assessment of cerebral blood flow, electrophysiologic parameters, and intracranial pressure, when appropriate, with cardiac and respiratory monitors are being developed at a number of traumatology centers world wide. Experience needs to be gained to establish the best combination of these modalities. Pending this, selected use of intracranial pressure monitoring combined with EEG and transcranial Doppler ultrasound provides reliable immediate assessment and ongoing monitoring of CNS structures.

Diagnosis and microsurgical approach to far-lateral disc herniation in the lumbar spine.

Lumbar-disc herniations that occur beneath or far lateral to the intervertebral facet joint are increasingly recognized as a cause of spinal nerve root compression syndromes at the upper lumbar levels. Failure to diagnose and precisely localize these herniations can lead to unsuccessful surgical exploration or exploration of the incorrect interspace. If these herniations are diagnosed, they often cannot be adequately exposed through the typical midline hemilaminectomy approach. Many authors have advocated a partial or complete unilateral facetectomy to expose these herniations, which can lead to vertebral instability or contribute to continued postoperative back pain. The authors present a series of 25 patients who were diagnosed as having far lateral lumbar disc herniations and underwent paramedian microsurgical lumbar-disc excision. Twelve of these were at the L4-5 level, six at the L5-S1 level, and seven at the L3-4 level. In these cases, myelography is uniformly normal and high-quality magnetic resonance images may not be helpful. High-resolution computerized tomography (CT) appears to be the best study, but even this may be negative unless enhanced by performing CT-discography. Discography with enhanced CT is ideally suited to precisely diagnose and localize these far-lateral herniations. The paramedian muscle splitting microsurgical approach was found to be the most direct and favorable anatomical route to herniations lateral to the neural foramen. With this approach, there is no facet destruction and postoperative pain is minimal. Patients were typically discharged on the 3rd or 4th postoperative day. The clinical and radiographic characteristics of far-lateral lumbar-disc herniations are reviewed and the paramedian microsurgical approach is discussed.

Posterior flank approach to the peritoneum for ventriculoperitoneal shunting.

We report a technique for insertion of a distal shunt catheter into the peritoneal cavity through a posterior incision. This has been helpful in patients with impaired access anteriorly. It may also be useful in elective situations. We have performed this procedure on 3 infants where the traditional anterior approaches would have been difficult due to subcutaneous scar tissue, ostomy sites and anterior intra-abdominal adhesions. This technique was safe and provided easy access to the peritoneal cavity. Complications would be similar to those for the standard ventriculoperitoneal shunts including bowel perforation, damage to the kidney or liver, infection and occasionally posterior cervical webbing that may cause pain locally or pull the head into an extended position.

Pressure changes within a chronic subdural hematoma during hemodialysis.

Spontaneous intracranial hemorrhage is not an infrequent complication of systemic anticoagulation, as occurs in hemodialysis. The neurological symptoms of subdural hematoma may be similar to those of dialysis disequilibrium. The pressure within a subdural fluid collection was monitored in a patient undergoing hemodialysis. The patient was known to become unresponsive during previous dialysis treatments. The initial pressure within the subdural cavity was measured to be -10.0 cm H2O prior to dialysis. The pressure within the collection decreased to a minimum value of -19.4 cm H2O during dialysis and stabilized at -16.4 cm H2O at the termination of dialysis. The neurological status changed subjectively during the procedure, with the patient becoming unresponsive to verbal stimuli as the intracranial pressure reached a minimum. These findings represent a syndrome similar to aliquorrhea, or low cerebrospinal fluid pressure within an otherwise asymptomatic subdural hematoma. Previously only increased intracranial pressure has been reported with hemodialysis.

Technique of stereotactic biopsy of two cranial target employing spherical coordinates to define a single trajectory.

A 'spherical coordinate system' has been developed to allow either stereotactic biopsy of two intracranial lesions using a single predetermined trajectory or biopsy of a single lesion through an existing burr hole. By means of the Gildenberg technique, the CT coordinates of the targets (or target and burr hole) are obtained. These are employed in three simple trigonometric equations to give three coordinates-two angles for the probe carrier (theta and alpha) and the radius (T) of a sphere, defined by one target as the center and the other target on the surface. These can be utilized in the Todd-Wells stereotactic frame. This system was evaluated using hollow skulls and crossed 30-gauge wire for phantom targets. The system was tried on ten different target combinations, and eight successful trajectories were obtained to within 3 mm. Two target combinations were inaccessible because of technical limitations of the Todd-Wells frame. This 'spherical coordinate system' can decrease the time to localize multiple targets as well as minimize the number of passes.