Reconstruction of the cranial base following tumour resection

Twenty-four patients have undergone resection of tumours involving the cranial base by a multidisciplinary team consisting of a neurosurgeon, ENT surgeon and plastic surgeon. The resultant defects of the cranial base have been reconstructed using local fascial flaps, transposition of local muscle flaps and microsurgical transfer of free muscle flaps. Indications for reconstruction have included obliteration of paranasal sinuses, coverage of tenuous dural repairs or dural grafts and separation of the nasopharynx from the dura of the frontal and temporal lobes and posterior fossa to prevent CSF leakage and meningitis.

Operative exposure and management of the petrous and upper cervical internal carotid artery

The exposure and operative management of the petrous and upper cervical internal carotid artery (ICA) in 29 patients is detailed. Twenty-seven of these patients had extensive cranial base neoplasms (benign or malignant), 1 had an inflammatory cholesteatoma, and 1 had an aneurysm of the upper cervical ICA immediately proximal to the carotid canal. Preoperative studies useful in the evaluation of these patients included computed tomography, magnetic resonance imaging, cerebral and cervical angiography, and a balloon occlusion test of the ICA with evaluation of neurological status and of cerebral blood flow. The exposure of the upper cervical and petrous ICA was useful to obtain proximal control of the cavernous ICA, aided in the operative approach to extensive petroclival, intracavernous, and parapharyngeal neoplasms, and enabled the total resection of 23 of 27 such tumors. A subtemporal and preauricular infratemporal fossa approach was most commonly used for the exposure of the artery. Intraoperative arterial management consisted of exposure and decompression only, dissection from encasing neoplasm, resection of the invaded arterial segment and vein graft reconstruction, or intentional arterial occlusion. Vascular complications included 1 stroke due to delayed arterial occlusion, 1 stroke and death due to infection spreading from the nasopharynx with bilateral ICA rupture, and 1 pseudoaneurysm formation secondary to wound infection necessitating postoperative balloon occlusion of the ICA. Nonvascular complications included facial nerve paralysis in 10 patients (usually temporary), glossopharyngeal and vagal paralysis in 13 patients requiring Teflon injection of the vocal cord in 9, temporary difficulties with mastication in 9 patients, and wound infection in 3. The surgical exposure and management of the upper cervical and petrous ICA may permit a total operative resection of extensive cranial base neoplasms and is also an alternative for the management of vascular lesions involving these segments of the artery. With malignant neoplasms extending from the nasopharynx, postoperative infection remains a problem and may best be resolved by the use of a vascularized rectus abdominis muscle flap to reconstruct defects of the nasopharynx. Bilateral ICA encasement by neoplasms is also a major problem to be solved. The value of such an aggressive approach to the management of malignant neoplasms remains to be proven.

Transtemporal approach to the skull base: an anatomical study

The surgical anatomy of a transtemporal approach to the structures of the clivus was defined with the aid of dissections in 10 cadaver heads. The steps in the dissection consisted of first exposing the cervical internal carotid artery (ICA), the internal jugular vein, and the caudal cranial nerves, each at the skull base; then performing small retromastoid and temporal craniotomies; and, finally, drilling away the petrous and tympanic bone to expose the intratemporal parts of the facial nerve, the petrous ICA, the sigmoid sinus, and the jugular bulb. To expose the structures of the lower clivus, the sigmoid sinus was ligated and divided, the facial nerve was displaced anterosuperiorly, and the inner ear structures were preserved. Dural opening exposed the anterolateral and anterior surfaces of the medulla, the pontomedullary junction, and the spinomedullary junction. The ipsilateral vertebral artery and often the contralateral vertebral artery and the vertebrobasilar junction, the caudal cranial nerves, and the origin of the 6th, 7th, and 8th cranial nerves were well exposed. To expose the structures of the middle clivus, we drilled away the labyrinth, the cochlea, and a portion of the clival bone. The facial nerve was displaced posteroinferiorly. Dural opening exposed the ipsilateral anterior surface of the pons, the midbasilar artery, and the ipsilateral 5th, 6th, 7th, and 8th cranial nerves. A portion of the contralateral anterior surface of the pons was also exposed at times. The superior limit of this exposure was just above the origin of the trigeminal nerve. The exposure of the upper clival structures was limited with this approach, and required medial temporal lobe retraction. Two case reports are included to illustrate the application of the transtemporal approach to the exposure and clipping of aneurysms of the vertebrobasilar system. The advantages and disadvantages of this approach are discussed.

Free rectus abdominis muscle flap reconstruction of the middle and posterior cranial base

A multidisciplinary approach by the neurosurgeon, ENT surgeon, and plastic surgeon has been used in seven patients with extensive tumors involving the middle and posterior skull base. Wide resection of these tumors was accomplished, and the resultant defect of the cranial base was reconstructed using free rectus abdominis muscle flaps. The free muscle flap has been used to reconstruct defects in the posterior and lateral walls of the nasopharynx, obliterate the exposed paranasal sinuses, and cover tenuous dural repairs or dural grafts overlying the temporal lobe and posterior fossa to prevent cerebrospinal fluid leakage and ascending meningitis.

Operative management of tumors involving the cavernous sinus

In the past, neurosurgeons have been reluctant to operate on tumors involving the cavernous sinus because of the possibility of bleeding from the venous plexus or injury to the internal carotid artery (ICA) or the third, fourth, or sixth cranial nerves. The authors describe techniques for a more aggressive surgical approach to neoplasms in this area that are either benign or locally confined malignant lesions. During the last 2 years, seven tumors involving the cavernous sinus have been resected: six totally and one subtotally. The preoperative evaluation included axial and coronal computerized tomography, cerebral angiography, and a balloon-occlusion test of the ICA. Intraoperative monitoring of the third, fourth, sixth, and seventh cranial nerves was used to assist in locating the nerves and in avoiding injury to them. The first major step in the operative procedure was to obtain proximal control of the ICA at the petrous apex and distal control in the supraclinoid segment. The cavernous sinus was then opened by a lateral, superior, or inferior approach for tumor resection. Temporary clipping and suture of the ICA was necessary in one patient. None of the patients died or suffered a stroke postoperatively. Permanent trigeminal nerve injury occurred in three patients; in two, this was the result of tumor invasion. One patient suffered temporary paralysis of the third, fourth, and sixth cranial nerves, and in another the sixth cranial nerve was temporarily paralyzed. Preoperative cranial nerve deficits were improved postoperatively in three patients. Radiation therapy was administered postoperatively to four patients. These seven patients have been followed for 6 to 18 months to date and none has shown evidence of recurrence of the intracavernous tumor.

Noninvasive detection of intracranial vascular lesions using an electronic stethoscope

Using an electronic stethoscope, the authors have attempted noninvasive detection of intracranial aneurysms, arteriovenous malformations (AVM's), and carotid cavernous fistulas in 45 patients. A microphone of older design and a newly designed horn-coupled probe microphone were used to record the sound signals emanating from the cranium. A trigger pulse recorded by another microphone placed over the carotid area or the precordium was used to time the intracranial signals. The sound signals were converted to electrical signals, amplified, filtered, and analyzed using fast Fourier transformation to give plots of amplitude versus frequency of the signals. A spike at a certain frequency or a bruit over a band of frequencies was considered a positive finding. The records of 18 of the patients were not satisfactory for analysis, mainly due to external noise interference. Eight of 11 aneurysm patients with satisfactory recordings emitted resonant spikes, turbulent bruits, or combinations of the two. The other three records were negative. Four patients with AVM's and two with carotid cavernous fistulas exhibited broad-band bruits representing turbulent flow. Neither spikes nor bruits were demonstrable in three patients with brain tumors or in seven patients without intracranial vascular lesions. Experimental vein pouch aneurysms were also induced in two dogs. Recordings from these animals revealed resonant spikes. The limitations and scope of electronic stethoscope audiometry are discussed.

Tentorial meningiomas: surgical management and results

We report the clinical features, radiological studies, operative management, and follow-up data in a series of 27 patients with tentorial meningiomas. Headache and extremity or gait ataxia were the most common presenting symptoms. Signs of elevated intracranial pressure and cranial nerve, pyramidal, or cerebellar deficits were the most common findings on neurological examination. Computed tomography was the single most important diagnostic tool. Cerebral arteriography was considered important to define arterial and venous relationships to the tumor. Two patients in the series underwent cerebrospinal fluid shunting only. The others underwent an operation on the tumor, with or without a shunt. There were 2 postoperative deaths early in the series, 1 due to cerebellar swelling and the other due to brain stem infarction. With an average follow-up of 5.5 years, 19 patients are independent and have resumed their premorbid level of activity. The pathological anatomy of these lesions is described. The different operative approaches to this tumor are discussed.

Cerebellopontine angle meningiomas. Microsurgical excision and follow-up results

During the years 1974 through 1981, 22 patients with cerebellopontine angle meningiomas underwent surgery: 14 tumors were excised completely, and eight subtotally. A retromastoid approach was used in 19 cases and a subtemporal approach in three cases. There was no operative mortality and the quality of survival was good. Five patients suffered new cranial nerve deficits as a result of the operation. The average follow-up period was 5 years. One tumor thought to be completely removed has recurred, but has not required another operation so far. One subtotally excised tumor required reoperation. Computerized tomography and arteriography were important in preoperative evaluation. Good neuroanesthesia, the use of the surgical microscope and microtechnique, and an understanding of the pathological relationships were factors contributing to good results.

A technique of clipping giant intracranial aneurysms with the preservation of the parent artery

Several methods are currently available for the treatment of giant intracranial aneurysms. In this report, we emphasize the technique of temporary trapping of the aneurysm followed by aspiration and collapse, and subsequent clipping. This method permits the preservation of the parent vessel and avoids the need for creating a microvascular bypass. Two cases are presented to illustrate this technique; in one case the patient had a giant middle cerebral artery aneurysm, and in the other a giant carotid-ophthalmic artery aneurysm. Both aneurysms were successfully clipped with preservation of the major vessels and a good result. On the basis of the configurations of their necks, giant aneurysms can be classified into three groups. The different methods of treating these aneurysms are reviewed with respect to this classification.

Thoracic disc herniation: operative approaches and results

In a series of 12 cases of thoracic disc herniation operated upon at the University of Pittsburgh, 4 different operative approaches were used. These included laminectomy in 2 early cases, posterolateral extrapleural operation in 5 cases, transthoracic operation in 3 cases, and transpedicular operation in 2 cases. The relative merits of the various approaches are discussed in this paper. The clinical presentation, radiological features, and follow-up data are also presented. Precise preoperative radiological diagnosis was essential in planning the operative strategy. The posterolateral and transpedicular approaches were both satisfactory, but the former had some advantages over the latter. With a mean follow-up period of 5 years, 5 patients were cured, 5 were improved, and 1 was unchanged. One patient was worse due to coexistent amyotrophic lateral sclerosis.

Contributions of engineering to the neurological sciences

Engineering technology has made several important contributions to the basic and clinical neurological sciences. However, technology has been criticized for dehumanizing patient care and for escalating the cost of medical care. We review several areas where engineering technology has advanced neuroscientific knowledge and improved the care of neurologically ill and impaired and also areas where significant contributions may be expected. Some of the problems of technological innovation such as cost, equipment failure, and standardization are discussed. The importance of focusing on ethical issues raised by technological progress is pointed out. Some suggestions are made for furthering the applications of technology to the neurological sciences.

Malfunctioning ventriculoperitoneal shunts. Clinical and pathological features

The authors report the clinical and pathological findings in 201 procedures to revise malfunctioning ventriculoperitoneal shunts in 114 patients. The revised shunts were predominantly Raimondi three-piece systems. Collection of fluid along the shunt track is emphasized as an early clinical feature of shunt malfunction. In some cases, there are few clinical signs of shunt infection, and the first indication of it may be shunt malfunction. Ventricular catheter obstruction was caused by tissue from the region in addition to choroid plexus. Inflammation was frequently found around both ventricular and peritoneal catheters. Foreign bodies (cotton fiber, hair, and talc) and granulomatous inflammation were often present at both ends. Tissues obstructing the peritoneal catheter included embolic neoplastic cells, choroid plexus, and leptomeninges. There was also more necrotic debris at the peritoneal end. To prevent shunt malfunction, attention should be directed to: 1) optimal placement of ventricular catheters inside the lateral ventricle; 2) prevention of infection; 3) avoidance of contamination by cotton fibers, hair, or talc; and 4) improvements in the biocompatibility of the implanted materials.

Diagnostic and therapeutic alternatives in patients with symptomatic "carotid occlusion" referred for extracranial-intracranial bypass surgery

An increasing number of patients with symptomatic carotid artery occlusion are being referred for extracranial to intracranial bypass grafts. After careful clinical and angiographic assessment, a number of these patients have been treated with a direct approach to the carotid arteries in the neck or with anticoagulation rather than with a bypass graft. These patients may be categorized diagnostically under the following heading: 1) complete occlusion of the internal carotid artery (ICA) with intracranial patency; 2) spontaneous dissection of the ICA: 3) atheromatous pseudo-occlusion; 4) carotid artery occlusion with stenosis of the contralateral ICA; 5) occlusion of the ICA and stenosis of the external carotid artery; and 6) thrombus in the intracranial segment of an occluded ICA. Each of these categories is discussed briefly, and illustrative cases are presented.

Origin, growth, and rupture of saccular aneurysms: a review

Pathological and hemodynamic concepts regarding the origin, growth, and rupture of intracranial saccular aneurysms are reviewed. Aneurysms form as a result of an interplay between hemodynamic factors, such as axial stream impingement and the water hammer effect, and structural weaknesses at apices of arterial bifurcations, such as congenital and acquired medial defects, funnel-shaped dilatations, and areas of thinning. Hypertension and time aid the formation of aneurysms. Unknown factors in women and in some families also play a role. Enlargement of aneurysms results from an interplay between mechanical factors, such as self-excitation and resonance, that produce structural fatigue and pathological processes of repair of the aneurysmal wall. Rupture of aneurysms is caused by the same hemodynamic factors that effect growth and is also influenced by extramural pressure. Pathologically, a major rupture may be preceded by fibrinous and leukocytic infiltration of the wall, bleb formation, and a minor hemorrhage. Such minor leaks can be followed by healing and growth. Aneurysms that escape major hemorrhage or heal successfully after a hemorrhage can grow to giant proportions, but remain susceptible to rupture despite their size, unless they become completely thrombosed. Intramural thrombosis may be stimulated by minor leaks and is dependent upon the physical characteristics of aneurysms. Experimental, angiographic, and clinical studies that pertain to the origin, growth, and rupture of aneurysms are also reviewed.

Atheromatous pseudo-occlusion of the internal carotid artery

In the past year, three patients were referred for microvascular bypass surgery for relief of symptoms secondary to an apparently occluded internal carotid artery (ICA). Careful review of the late films of their initial arteriographic series or repeat arteriography with a specialized technique revealed a thin trickle of contrast medium flowing antegrade through a region of extreme stenosis. This thin line of contrast material ascended slowly to meet the column of contrast medium in the cavernous carotid segment that was filling by collateral circulation. Surgical exploration of the neck in these patients revealed a patent but collapsed ICA distal to a localized atheromatous plaque. These patients have been asymptomatic following carotid endarterectomy. This distinctive angiographic appearance may be described as "atheromatous pseudo-occlusion." Once recognized, carotid endarterectomy is the logical treatment of choice.

Pseudogrowth in skull fractures of childhood

We report two cases in which linear fractures of the parietal bone in infants healed spontaneously after initial enlargement suggested growth of the fracture line. We suggest the term "pseudogrowing skull fracture" to indicate this phenomenon. Growing skull fractures are best managed by early surgical correction. It is, therefore, important to recognize that some fractures may heal after an initial period of growth.

Carotid-cavernous sinus thrombosis caused by Aspergillus fumigatus. Case report

A case is presented of Aspergillus fumigatus granuloma involving the sphenoid sinus, sella turcica, cavernous sinus, and the internal carotid artery. The diagnosis was established by a transsphenoidal biopsy. The infection proved difficult to treat and finally remitted after chemotherapy with a combination of amphotericin B, rifampin (rifampicin), and flucytosine (5-fluorocytosine). The spectrum of aspergillosis of the central nervous system is reviewed, and difficulties in treating this infection are considered.

Carotid-cavernous fistula following percutaneous retrogasserian procedures. Report of two cases

Carotid arterial puncture during percutaneous retrogasserian procedures is a common but usually harmless complication. Strokes, resulting presumably from carotid artery thrombosis, have been reported previously following percutaneous retrogasserian coagulation. The authors report two cases of carotid-cavernous fistula, one following percutaneous radiofrequency rhizotomy and the other after percutaneous retrogasserian block. The latter patient had an anomaully by intracavernous injection of isobutyl-2 cyanoacrylate, using intra-arterial balloon flotation catheters. Carotid-cavernous fistula is a potentially serious complication of such procedures, and may be more common than realized since small fistulas may close spontaneously.

Ultrasonic B-scan echoarteriographic imaging of experimentally induced thrombi in dogs

Ultrasonic echoarteriography is a noninvasive method of visualizing extracranial arteries in health and disease. The real-time echoscanning device developed at the University of Cincinnatti utilizes a 5-MHz (center frequency) pulse-echoimaging system. B-mode pictures of the tissues studied are obtained and displayed on a video screen, real-time operation being provided by the scanning mechanism operating at 30 frames per second. In our experiments internal arterial damage produced by surgically scraping the intima induced experimental thrombosis in nine carotid in nine carotid and three femoral arteries in dogs. Where pathologically demonstrated, the thrombi were demonstrated by ultrasonic echoarteriography in every instance. Echoarteriography seemed more sensitive than contrast arteriography in the detection of a partially occlusive thrombus.