Saphenous vein graft bypass of the cavernous internal carotid artery

Vascular considerations and complications in cranial base surgery

The technical evolution of cranial base surgery has resulted in approaches that allow more radical surgical extirpation of complex cranial base lesions. Our service has extensively applied these cranial base approaches for lesions of the cranial base. A subgroup of 100 patients who had cranial base tumors involving potential manipulation or sacrifice of carotid arteries underwent 20-minute balloon test occlusions coordinated with vascular assessments consisting of a combination of the following: 1) four-vessel cerebral angiogram with compression studies; 2) occlusion transcranial Doppler ultrasonography; 3) occlusion single-photon emission computed tomography perfusion studies; and 4) xenon-133 cerebral blood flow studies. Transient neurological deficits associated with balloon test occlusion occurred in 7 of 100 patients (7%). Subsequently, 18 patients underwent permanent carotid occlusion by endovascular detachable balloons. Delayed ischemic complications (> 72 h) occurred in 4 of 18 (22%) patients. Additionally, a number of vascular complications not predicted by the balloon occlusion tests and vascular assessments were experienced. Repeat vascular assessments defined the causes and guided treatment of ischemic patients. Ischemic complications were caused by hemodynamic insufficiency, embolization, vasospasm, radiation vasculopathy, and venous anomaly. Our experience leads us to believe that no vascular assessment exists today that can predict the occurrence of vascular complications accurately. The current enthusiasm for cranial base surgery must be tempered with the sober reality that management of cerebrovascular anatomy and physiology remain significant limitations. Consideration of potential cerebrovascular complications is paramount to successful outcome and implementation of cranial base surgery.

Infiltration of the carotid artery by cavernous sinus meningioma

Intracranial meningiomas are known to infiltrate surrounding structures such as the calvaria and dural sinuses, and the brain itself. The issue of whether meningiomas invade major intracranial arteries is of clinical importance, particularly in the case of meningiomas of the cavernous sinus. If a meningioma has not invaded the carotid artery wall, complete tumor removal may be accomplished with careful dissection from the carotid artery; however, if the tumor has infiltrated the wall of the carotid artery, complete removal may require sacrifice of the artery. To determine whether cavernous sinus meningiomas invade the carotid artery, the authors retrospectively reviewed the histopathology of 19 consecutively treated individuals whose carotid artery was sacrificed during removal of a meningioma involving the cavernous sinus. Patients were selected for carotid artery resection based on preoperative magnetic resonance imaging studies demonstrating complete encasement of the artery. Reconstruction of the carotid artery was planned depending on the results of preoperative balloon test occlusion with blood flow determinations. None of the 19 patients had pathological evidence of malignant tumor. Eight individuals (42%) were found to have infiltration of the carotid artery by meningioma. In five cases, focal involvement of the adventitia of the carotid artery wall was noted and, in three, the vessel was infiltrated up to the tunica muscularis. In no case was the tunica muscularis invaded by tumor. Thus, meningiomas of the cavernous sinus do infiltrate the internal carotid artery and, in order to completely resect these lesions and effect a surgical cure, it may be necessary to sacrifice the carotid artery with or without reconstruction.

Review of skull base surgery approaches: with special reference to pediatric patients

The techniques of skull base surgery attempt to maximize the exposure of a cranial base lesion while using the least amount of brain retraction. Cranial base surgery is not a 'new' area of neurosurgical or otolaryngologic interest, but instead represents a resurgence of efforts to treat difficult lesions involving the cranial base. This resurgence of interest and effort is a product of recent advances in microanatomical knowledge of the cranial base, advances in microsurgical technique, improved neurophysiologic monitoring, and improved collaborative relationships between neurosurgery, otolaryngology and plastic surgery. Furthermore, improved neuroanesthetic techniques allow the surgeon to proceed with surgery without undue concern about time, and improved neuroimaging techniques provide the surgeon with detailed knowledge of the three dimensional characteristics of the tumor and surrounding structures. This review will focus on the surgical management of cranial base tumors primarily affecting the pediatric population. Little has been written on the techniques of skull base surgery as they apply to the pediatric population, since cranially-based tumors are a relatively rare occurrence in this patient population. In most instances, however, many of the 'standard' skull base approaches can be applied to the pediatric patient with few modifications, and in our experience, the pediatric patients have tolerated these approaches as well as their adult counterparts.

Validity of test occlusion studies prior to internal carotid artery sacrifice

Twenty-nine patients with lesions of the neck, skull base, and cavernous sinus had test balloon occlusions of the internal carotid artery (ICA) to determine the feasibility of sacrifice of the artery. Only one patient (3.4%) showed evidence of cerebrovascular compromise. Sixteen patients who tolerated test occlusions went on to ICA sacrifice. Ten patients had permanent balloon occlusion (PBO) of the ICA for cavernous aneurysms or to "trap" carotid-cavernous fistulae (CCF). Complications occurred in three patients (30%) with permanent morbidity in one patient (10%). One patient with CCF had PBO of the proximal ICA only, resulting in an unstable neurologic state and ultimately in death. Two patients had resection of skull base tumors 2 and 6 days after PBO of the ICA. Both suffered strokes and one died. Three patients had surgical sacrifice of the ICA without PBO. Two of these patients suffered cerebral ischemia without permanent sequelae. We conclude that test occlusion of the ICA with clinical monitoring will miss a significant number of patients with inadequate cerebrovascular reserve. Sensitivity is improved by controlled reduction of systemic blood pressure during the test occlusion. Resection of a skull base tumor soon after PBO of the ICA should be done in a delayed fashion or preceded by extracranial-intracranial arterial bypass. Patients who have had the artery sacrificed should be monitored in an intensive care setting for 48 hours to avoid hypotension, which could cause cerebrovascular ischemia.

Meningiomas of the cranial base

Treatment objectives for meningiomas of the cranial base include relief of neurologic disability and prevention of clinical progression or recurrence with the least morbidity. Recent advances in skull base surgical techniques, through an appreciation of skull base anatomy and institutional specialization, have contributed major improvements to the outlook for patients with these tumors, and previously inoperable cases may now often be removed completely with acceptable risk. Since significant morbidity may be incurred during surgical resection of these difficult lesions, especially in terms of cranial nerve dysfunction, the value of aggressive surgical resection must be weighted against the often indolent natural history of these lesions, and must be individualized in each patient. Completeness of resection is the major prognostic factor determining the outcome of patients with typical benign meningiomas in terms of length of survival, risk of recurrence, and neurological disability. Various means of prognosticating the growth potential of a given tumor are being investigated, though none have yet been confirmed for their predictive value in typical, histologically benign meningiomas. The role of external beam radiotherapy has not been subjected to adequately controlled, prospective studies, and there is currently insufficient followup to assess the risks and benefits of stereotactic radiosurgery. Advances in the clinical management of tumors of the skull base has had perhaps the greatest impact for patients with meningiomas who constitute a large portion of tumors seen in these locations. Although the majority have benign histological features, skull base meningiomas can present a formidable challenge due to their proximity to vital structures, surgical inaccessibility, and occasional aggressive features. The combination in recent years of advances in skull base surgical techniques, adjuvant therapy, and rehabilitation methods have dramatically improved the outcome for these tumors.

Vein graft replacement of the middle cerebral artery after unsuccessful embolectomy: case report

A forty-one-year-old man with a cavernous hemangioma of the right cavernous sinus underwent a preoperative cerebral angiogram and a balloon occlusion test of the internal carotid artery. During the operation to remove the cavernous sinus lesion, the ipsilateral electroencephalogram was found to be abnormal. An embolic occlusion of the M2 and M3 segments of the middle cerebral artery (MCA) was discovered. A platelet and thromboembolus was removed via multiple incisions, and flow was restored. The cavernous sinus lesion was removed uneventfully. At the end of the operation, the MCA was found to be reclotted. Flow was eventually restored by replacing the M2 segment of the MCA with a 2-cm saphenous vein graft. The patient recovered without any deficits of brain function and with transient deficits of Cranial Nerves III and VI. Computed tomography revealed infarcts in the temporal and parietal areas. When MCA embolectomy is unsuccessful, vein graft replacement should be considered to restore flow and to avoid major neurological deficits.

Vein graft replacement of the distal vertebral artery

Vein graft reconstruction of the cervical portion of the vertebral artery has been commonly used for the treatment of atherosclerotic arterial disease. In this article, we describe two instances of vein graft replacement of the distal portion of the vertebral artery. In the first case, the vein graft was placed from C2 transverse foramen to the intradural portion of the vertebral artery to replace an artery abnormally encased and involved by meningioma. The grafting was done in this case to preserve the cerebrovascular reserve in a young patient. In the second case, a vein graft was placed from the extradural C1 portion to the intradural artery beyond the posterior inferior cerebellar artery. This was done to replace a segment of the artery involved by a giant aneurysm, which could not be clipped without occluding the parent artery. In this case, the vein graft replacement was necessitated by changes of somatosensory evoked potentials after the aneurysm was clipped, demonstrating the need to preserve the patency of the artery. Vein graft replacement of the proximal intradural vertebral artery is feasible by the combination of standard cerebro-vascular techniques and the exposures afforded by skull base surgery.

Contralateral external carotid-to-middle cerebral artery graft using the saphenous vein. Case report

A variation of the extracranial-intracranial arterial bypass, using a long saphenous vein graft, is presented. The saphenous vein graft was inserted from the contralateral external carotid artery to the distal middle cerebral artery to replace the common and internal carotid arteries in a patient with a large neck tumor that invaded the common and internal carotid arteries, the esophagus, and the trachea. The patient had a positive balloon Matas' test. The saphenous vein was covered with an artificial vascular graft so that turning of the head or movement of the mandible did not displace or compress the graft. A large volume of flow began immediately after anastomosis. A description of the case and the operative technique is presented herein.

En bloc resection of an ethmoid carcinoma involving the orbit and medial wall of the cavernous sinus

The involvement of the cavernous sinus by malignant tumors has limited their surgical treatment. We report here a successful en bloc resection of an invasive ethmoid carcinoma involving the cavernous sinus in a 46-year-old man. To prepare for surgery on this patient, a cadaver study was performed to investigate the feasibility of en bloc cavernous sinus resection and reconstruction. The preoperative evaluation, operative approach, and postoperative management are presented.

Temporal bone neoplasms: a report on 20 surgically treated cases

The surgical resection of neoplasms involving the petrous bone and surrounding areas in 20 patients is reported. Technical advances described include the total resection of several tumors previously considered inoperable due to involvement of dura and brain, petrous internal carotid artery (ICA), the vein of Labbé, and adjacent areas such as the clivus and the cavernous sinus. Areas of reconstruction after resection included the ICA, the seventh and 11th cranial nerves, and the cranial base, often requiring the use of vascularized flaps. There were no intraoperative deaths. Many patients experienced significant temporary morbidity related primarily to wound healing and to lower cranial nerve palsy; however, all but three patients (all with fast-growing malignancies) returned to their preoperative functional status. During a median follow-up period of 30 months (range 17 to 63 months), the 10 patients with benign tumors and slow-growing malignancies fared well, seven being alive and disease-free. The 10 patients with fast-growing malignancies fared poorly, only two being alive without disease. This outcome appeared to be related to tumor pathology and extent of invasion; both survivors harbored tumors confined to the petrous bone. An anatomical classification system of tumor spread is introduced, which should be considered concomitantly with tumor pathology.

The combined supra- and infratentorial approach for lesions of the petrous and clival regions: experience with 46 cases

The combined supra- and infratentorial approach has been subdivided into three variations: the retrolabyrinthine technique (petrous bone resection with preservation of hearing); the translabyrinthine technique (greater petrous bone resection and sacrifice of hearing); and the transcochlear technique (maximum petrous drilling, sacrifice of hearing, and transposition of the facial nerve). These three variations maximize temporal bone drilling and therefore provide exquisite exposure of the clivus and petrous regions with minimal or no brain retraction. The superior petrosal sinus is always sacrificed and the tentorium completely cut. The sigmoid sinus can be transected or kept intact, depending on the venous drainage and the degree of exposure required. A series of 46 patients who underwent the combined approach is presented.

Aneurysms of the intracavernous carotid artery: a multidisciplinary approach to treatment

Of 43 cavernous sinus aneurysms diagnosed over 6 1/2 years, 23 fulfilled indications for treatment; of these 19 were treated, eight surgically and 11 with interventional radiological techniques. Six small and two giant aneurysms were treated surgically: four were clipped, two were repaired primarily, and two were trapped with placement of a saphenous-vein bypass graft. Seven large and four giant aneurysms were treated with interventional radiological techniques: in five cases the proximal internal carotid artery (ICA) was sacrificed; one aneurysm was trapped with detachable balloons; and five were embolized with preservation of the ICA lumen. The mean follow-up period was 25 months. At follow-up examination, three patients in the surgical group were asymptomatic, two had improved, and three had worsened. Three of these patients had asymptomatic infarctions apparent on computerized tomography (CT) scans. At follow-up examination, four radiologically treated patients were asymptomatic, five had improved, two were unchanged, and none had worsened. One patient had asymptomatic and one minimally symptomatic infarction apparent on CT scans; both lesions were embolic foci after aneurysm embolization with preservation of the ICA. It is concluded that treatment risk depends more on the adequacy of collateral circulation than on the size of the aneurysm. A multidisciplinary treatment protocol for these aneurysms is described, dividing patients into high-, moderate-, and low-risk groups based on pretreatment evaluation of the risk of temporary or permanent ICA occlusion using a clinical balloon test occlusion coupled with an ICA-occluded stable xenon/CT cerebral blood flow study. Radiological techniques are suggested for most low-risk patients, while direct surgical techniques are proposed for most moderate- and high-risk patients.

The use of an intraluminal shunt for bypass grafts of the cavernous internal carotid artery. Technical note

The authors describe an indwelling intraluminal shunt for use during graft bypass procedures of the cavernous internal carotid artery. The clinical use of this shunt in a patient with meningioma invading the right cavernous sinus is described. This shunt has also been found applicable during carotid endarterectomy, and should prove to be a useful addition to the neurosurgical armamentarium for skull-base surgery.

Direct surgery of the cavernous sinus: patient selection

The cavernous sinus is involved either in lesions arising primarily in the sinus or in lesions invading the sinus from surrounding structures. Experience with direct surgery of the cavernous sinus is encouraging, but no conclusive evidence exists concerning the roles of conservative, surgical, and radiological treatments in terms of effectiveness, morbidity, and long-term results. Consequently, management is individualized according to the patient and the lesions. We discuss these factors in patient selection for cavernous sinus surgery.

Management of tumours involving the cavernous sinus

The operative experience with 137 tumours of the cavernous sinus at the University of Pittsburgh during the past 7 years is reported. The importance of the normal and tumour-infiltrated cavernous sinus anatomy and imaging is delineated. 63% of the tumours are benign, primarily meningiomas, for which an anatomical grading system is presented. The various operative approaches to the cavernous sinus are described. 88% of the meningiomas were totally resected. There was a 1.5% operative mortality and 1.5% severe morbidity rate. Initial ipsilateral opthalmoplegia progressively improved in the majority of patients. For all patients with at least 6 months of follow up of benign tumours, the intracavernous tumour recurrence rate was 3% and total recurrence rate was 6%.