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.

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.

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 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.

Retrograde suction decompression of giant paraclinoidal aneurysms. Technical note

Giant paraclinoidal carotid artery aneurysms frequently require temporary interruption of local circulation to facilitate safe occlusion. Due to brisk retrograde flow through the ophthalmic artery and cavernous branches, simple trapping of the aneurysm by cervical internal carotid artery clamping and intracranial distal clipping may not adequately soften the lesion. The authors describe a retrograde suction method of aspiration of this collateral supply which they have used in over 40 cases. After temporary trapping, a No. 18 angiocatheter is inserted into the cervical internal carotid artery. This catheter is then connected to a wall suction point allowing rapid aneurysm deflation. This technique, accomplished by the surgical assistant, permits the surgeon the freedom to use both hands in dealing quickly with the aneurysm.

Causes of morbidity and mortality from surgery of aneurysms of the distal basilar artery

Despite modern neurosurgical technology and neuroanesthetic care, treatment of aneurysms of the distal basilar artery remains fraught with complications. Between 1982 and 1988, 126 patients with aneurysms of the distal basilar artery who had been treated by 2 surgeons were retrospectively analyzed to determine the causes of morbidity and mortality from this disease and its treatment. Ten patients (8%) died, and 14 patients (11%) suffered permanent neurological disability after treatment. The causes of failed management could be grouped into the following categories: 1) direct effects of hemorrhage; 2) errors in surgical timing; 3) conceptual errors; 4) technical errors; 5) morbidity from delayed cerebral ischemia; and 6) complications of hypertensive/hypervolemic therapy for symptomatic vasospasm; a small group of patients who died despite having received what we consider excellent management were grouped under a seventh category, "bad luck." Frequently, patients who did poorly suffered from multiple complications, each of which contributed to their overall morbidity. It is our hope that increased awareness of these potential pitfalls and the further evolution of intravascular technique in selected cases will, in time, improve the outlook for patients suffering from these dangerous lesions.

Evidence of redistribution of cerebral blood flow during treatment for an intracranial arteriovenous malformation

The presence of an intracranial arteriovenous malformation has a dramatic impact on local circulatory dynamics. Treatment of some arteriovenous malformations can result in disastrous hyperemic states caused by redistribution of previously shunted blood. This report describes serial hemodynamic measurements of both cerebral blood flow and flow velocity in 3 patients during treatment for arteriovenous malformations. Measurements of cerebral blood flow were made by computed tomographic scan employing the stable xenon inhalation technique; flow velocity, including autoregulatory characteristics, was measured by transcranial Doppler ultrasonogram. Substantial hyperemia developed in one patient (Case 1) after resection and in another (Case 3) after embolization. Embolization resulted in restoration of normal regional cerebral blood flow in a patient who demonstrated hypoperfusion before treatment (Case 2). In Patient 1, postoperative hyperemia was associated with persistently elevated flow velocities, and may have been accompanied by hemispheric neurological deficits. Sequential hemodynamic measurements may predict patients at risk of perioperative complications, and may become useful clinical guidelines for the extent and timing of embolization and for the timing of surgery after intracranial hemorrhage or preoperative embolization procedures.

Reversible middle cerebral artery embolization in dogs without intracranial surgery

Using dogs, we developed an intravascular model for reversible middle cerebral artery occlusion that does not involve intracranial surgery or enucleation. Using silicone plastic plugs with a suture embedded within them, we embolized the middle cerebral artery in 19 dogs via the cervical carotid artery. The free end of the suture remained accessible in the neck, and after variable dwell times traction was placed on the suture and the plug was withdrawn. Placement of the plug in the middle cerebral artery produced ischemia in the basal ganglia. The degree and distribution of cortical ischemia were variable as evidence by the pathologically documented scattered nature of infarcts that resulted when the plug was left permanently in the middle cerebral artery and when it was removed after 1 or 2 hours. Angiography demonstrated occlusion of the middle cerebral artery with the plug in place as well as reperfusion when the plug was withdrawn. This modification of a previously described model of middle cerebral artery occlusion provides an opportunity to study structural, physiologic, and biochemical events occurring in acutely hypoperfused cerebral tissue as well as critical changes leading to irreversible injury without the disadvantages of surgical manipulation required by all previous models of reversible cerebral ischemia.

Microfibrillar collagen model of canine cerebral infarction

A new canine model of focal cerebral ischemia has been developed employing intravascular delivery of microfibrillar collagen via femoral catheterization. In 13 dogs, dose-effect studies showed neurologic deficits (ranging from mild hemiparesis to death) related to the dose of microfibrillar collagen delivered. In another 10 dogs, 0.5 ml of 60 mg/ml microfibrillar collagen was injected into the common carotid artery; neurologic assessment over 48 hours revealed a survivable stroke syndrome in seven dogs, death at 40 hours in one dog and at less than 12 hours in another, and no clinical effect in one dog. The eight surviving dogs were sacrificed at 48 hours; nine of the 10 dogs had middle cerebral artery distribution infarcts (two grossly hemorrhagic and five grossly nonhemorrhagic) on histologic examination. Angiography in three dogs demonstrated no significant major vascular occlusion. All seven dogs with survivable strokes demonstrated a dense hemiparesis at 24 hours that improved to ambulatory status at 48 hours. The use of microfibrillar collagen to produce middle cerebral artery strokes in dogs provides a new opportunity to study cerebral ischemia without surgery involving the cervical or cranial vasculature. Dogs have larger brains than other common animal models and thus are more amenable to study with imaging modalities. A model with a measurable but survivable insult provides an opportunity for short- and long-term clinical follow-up and for the investigation of therapeutic interventions.

Cerebrovascular hemodynamics in arteriovenous malformation complicated by normal perfusion pressure breakthrough

Catastrophic hyperemic states are known complications after the treatment of certain types of intracranial arteriovenous malformations (AVMs). A case is presented in which a large AVM was preoperatively embolized and later resected. There was clear intra- and postoperative evidence of edema and hemorrhage, which resulted in a fatal outcome. Regional cerebral blood flow (rCBF) data from this patient obtained with single photon emission computed tomography (SPECT) both before and after embolization were compared with data from four patients with similar size supratentorial AVMs treated and studied in a similar protocol who did not develop perfusion breakthrough. Pretreatment hemispheric rCBF was significantly reduced in this patient's ipsilateral hemisphere (50 ml/100 g/min) compared to the control group mean (83 +/- 9.5 ml/100 g/min). A similar relative depression was found in the contralateral hemisphere. After therapeutic embolization, the ipsilateral rCBF increased by 33 ml/100 g/min and the contralateral hemispheric rCBF increased by 30 ml/100 g/min; this embolization-induced increase in rCBF was significantly higher than in the control group. Acetazolamide, known to increase rCBF in normal tissue by 35 +/- 3%, resulted in a 56% augmentation of ipsilateral hemispheric flow before embolization in the reported patient vs. a 22 +/- 10% increase for the control group. Postembolization, this hyperresponsiveness to acetazolamide remained unchanged. It is possible that these hemodynamic derangements may indicate a dissociation between the vasoconstrictive and vasodilatory reactivity in chronically hypoperfused territories adjacent to AVMs such that pharmacological or metabolic stimuli may induce further vasodilation, but sudden redistribution of large volumes of flow will not promote protective vasoconstriction.

Use of etomidate, temporary arterial occlusion, and intraoperative angiography in surgical treatment of large and giant cerebral aneurysms

The operative management of large and giant aneurysms is complicated by their typically atheromatous and thick walls, frequent intramural thrombosis with calcification, and broad-based necks that often incorporate perforating and other vital vessels. Not infrequently, it is necessary to at least focally arrest the intracranial circulation and open or excise these aneurysms to facilitate vascular reconstruction. This maneuver, in patients whose disease processes have destroyed autoregulatory function or who have inadequate sources of anatomical collateral supply, may cause the threshold for permanent ischemic injury to be exceeded. The authors have recently treated 14 such patients while under electroencephalographic monitoring to document electrical burst suppression induced by the administration of etomidate, followed by temporary clipping to permit vascular repair and intraoperative angiography to document patency of parent arteries. Up to 60 minutes of internal carotid artery occlusion, 35 minutes of middle cerebral artery occlusion, 19 minutes of upper basilar artery occlusion, and 4 1/2 minutes of lower basilar artery occlusion have been well tolerated using this protocol. In such situations, etomidate may be effective in protecting the cerebral circulation without the detrimental cardiotoxicity observed with protective doses of barbiturates.

Subtemporal transdural use of detachable balloons for traumatic carotid-cavernous fistulas

Endovascular use of detachable balloons has revolutionized the management of carotid-cavernous fistulas so that the goals of angiographic elimination of fistula and preservation of carotid patency can usually be achieved nonsurgically. Certain circumstances of flow dynamics and anatomy, however, make an endovascular approach difficult for even an experienced interventional neuroradiologist. Fistulas involving the posterior carotid wall at its proximal cavernous entry and the anterior carotid wall in its initial horizontal intracavernous segment, as well as very low flow fistulas at other sites, have posed particular problems. Three patients with such traumatic fistulas whose endovascular treatment failed were managed by the direct transdural introduction of balloons. Intraoperative angiography was accomplished with open internal carotid artery (ICA) catheterization and the use of a portable C-arm with a 6-in. image intensifier. After temporal craniectomy and subtemporal exposure, the course of the cavernous ICA was mapped out with spinal needles and the site of the fistula was localized by intraoperative angiography. An incision was then made in the lateral wall of the cavernous sinus, and latex balloons were manually introduced via a 7 French introducer sheath. The balloons were inflated under angiographic control and detached when the fistula was obliterated. This simple technique was initially successful in three patients; the fistula was eliminated with preservation of carotid patency. One patient suffered a recurrence of his fistula 2 months postoperatively while lifting weights, and one patient developed a new 3rd nerve palsy after operation.

Use of the extracranial-intracranial arterial bypass in the management of refractory vasospasm: a case report

Cerebral arterial vasospasm after aneurysmal subarachnoid hemorrhage remains one of the major causes of morbidity and mortality in patients surviving the initial hemorrhage. Once established, no known method has been shown to reverse this process in humans. Although intravascular volume expansion and induced arterial hypertension have been shown to be effective in the reversal of neurological deficits secondary to vasospasm, a large proportion of patients remain refractory to these methods. We report one such case successfully managed by the establishment of an extracranial-intracranial anastomosis in an attempt to augment collateral flow.

Resection of upper aerodigestive tract tumors involving the middle cranial fossa

Benign and malignant neoplasms of the upper aerodigestive tract that invade the middle cranial fossa are frequently considered unresectable due to the proximity of the cavernous sinus and internal artery, and to the inaccessibility of this region via conventional surgical approaches. We report our experience using a combined, lateral intracranial and infratemporal fossa procedure for the management of these tumors in four patients. Successful removal of neoplasm associated with minimal morbidity was accomplished in 3 patients, 2 with angiofibromas and 1 with an adenoid cystic carcinoma. The postoperative course of the fourth patient was complicated by meningitis which resulted in the patient's death five months following resection of an adenocarcinoma.

Saphenous vein interposition grafts in the microsurgical treatment of cerebral ischemia

Saphenous vein interposition grafts of varying lengths have been used in 25 extracranial-intracranial bypasses since 1974. Indications for operation included transient ischemic episodes (13 cases), prophylactic augmentation of middle cerebral artery (MCA) collateral flow prior to surgical treatment of intracranial aneurysm (four), and traumatic occlusion of cervical or intracranial internal carotid arteries (eight). Vein grafts to cortical branches of MCA originated from superficial temporal or occipital arteries in ten cases, common or external carotid arteries in ten, and subclavian or innominate vessels in five. Twenty-one patients have been followed up for a minimum of 12 months. Immediate patency rate was 84%; one late graft occlusion decreased overall patency to 80%. There was one operative mortality. Early technical problems, including donor-recipient size disparity, anastomotic distortion, and inappropriate graft routing, have been overcome by the use of 2-mm veins, the avoidance of hydrostatic dilation, and the construction of retroauricular tunnels. It is reasonable to assume that long-term patency of these reconstructions will parallel that of extracranial-intracranial bypasses using autologous arteries.

Management of penetrating injuries of the internal carotid artery at the base of the skull utilizing extracranial-intracranial bypass

Penetrating injuries of the internal carotid artery at the base of the skull often require permanent or transient occlusion of the injured vessel during repair. Extracranial-intracranial bypass (EC-IC) was employed in five patients to insure adequate cerebral perfusion during cervical exploration. Preoperative neurologic deficits were noted in three patients; two demonstrated complete reversal following EC-IC. This experience suggests that EC-IC can maintain adequate cerebral perfusion during repair of internal carotid injuries and allow selective revascularization of patients with neurologic deficit and carotid occlusion.

Traumatic middle cerebral artery aneurysm: case report

A case of traumatic middle cerebral artery aneurysm is presented. The case demonstrates some of the difficulties encountered when dealing with this type of aneurysm. The unusual surgical approach required for obliteration is described.

Failure of extracranial-intracranial arterial bypass in acute middle cerebral artery occlusion: case report

Extracranial-intracranial arterial bypass procedures provide important augmentation of collateral circulation to cortical areas rendered potentially ischemic by therapeutic occlusion of major branches of the circle of Willis. Although the case studies reported to date in general reflect positively on this use of the bypass procedure, this report of a patient who failed to tolerate acute middle cerebral artery occlusion despite the presence of a patent superficial temporal-middle cerebral artery branch anastomosis points up several of the practical and theoretical limitations of this therapeutic approach. Certain modifications of the timing of the bypass procedure, the selection of donor and recipient arteries, and the mechanics of intracranial arterial occlusion may allow a wider application of extracranial-intracranial arterial bypass in this therapeutic setting.

Risk of intracranial aneurysm surgery in the good grade patient: early versus late operation

To evaluate the risk of definitive intracranial microsurgical aneurysm obliteration as a function of the timing of the operative intervention, we retrospectively reviewed 106 consecutive patients in good clinical condition who underwent such surgery. The patients who were operated upon within the first 8 days of their most recent subarachnoid hemorrhage formed the "early" group; the patients operated upon between the 9th and 31st day were considered to have undergone "late" surgery. On the basis of their clinical outcome the patients were allocated to one of four outcome categories ("good," "fair," "death") both at the time of their hospital discharge and at their most recent clinical re-evaluation, a minimum of 6 months after discharge from the hospital. There was no significant difference in the operative mortality in each group (early surgery, 5%; late surgery, 4%); additionally, no significant difference was noted in the incidence of either intraoperative complications or postoperative morbidity. A suggestive but statistically insignificant increase in the incidence of postoperative cerebral ischemic events was seen in the "early" surgery group (8% vs. 4% for the "late" surgery group). The potential significance of these findings for the timing of intracranial aneurysm surgery is discussed.

Microsurgical treatment of transient cerebral ischemia. Preliminary results in 50 patients

Extracranial-intracranial arterial bypass is a microneurosurgical procedure recently introduced in the treatment of a variety of cerebrovascular ischemic states. Fifty patients with transient ischemic attacks (TIAs) localized to the distribution of the internal carotid artery underwent this procedure during a 48-month period. All have been followed up for at least 14 months after surgery. There were no operative deaths, and notable postoperative morbidity has been experienced in less than 8% of cases. Seventy-six percent of patients have been asymptomatic since surgery, 14% have continued to experience TIAs, and 6% have had completed strokes (2% occurring in the operative hemisphere).

Microsurgical evaluation of the pterional approach to aneurysms of the distal basilar circulation

The microsurgical correlates the pterional approach to the distal basilar circulation were evaluated in 20 cases of posterior circulation aneurysms, 50 human cadaver dissections, and a variety of other intracranial surgical lesions. The pterional approach permitted successful clipping of the aneurysm in 13 of 15 basilar bifurcation aneurysms, 1 of 2 basilar-posterior cerebral aneurysms, and 2 of 3 basilar-superior cerebellar aneurysms. In each of the failed attempts via the pterional approach, the subtemporal route ultimately resulted in proper clip application. The interposition of the posterior clinoid process was the impediment to successful clipping in three of the four cases that could not be managed via the pterional approach. All 3 of these patients had a basilar bifurcation that was below the level of the posterior clinoid on angiography, whereas none of the remaining 17 aneurysm patients demonstrated a low-lying bifurcation. Posterior displacement of the basilar artery away from the posterior clinoid exceeded 1 cm in only 13% of our cases and was not an impediment to successful clipping of the aneurysm via the pterional route. We conclude that, when the anatomical situation is appropriate, the pterional approach offers the advantages of less brain retraction and better visualization of the parent arteries and important perforating branches when compared to the subtemporal approach.

Extracranial-intracranial (EC-IC) arterial bypass: past performance and current concepts

The authors present a review of published experience with intracranial-extracranial arterial bypass grafting. The procedure is technically feasible and has a relatively low morbidity and mortality when performed by experienced microvascular surgeons. However, its therapeutic value is still unproven.