Aldo Spallone

An Anatomicosurgical Study of the Temporal Branch of the Facial Nerve

The surgical anatomy of the temporal branch of the facial nerve was studied bilaterally in 10 embalmed cadaveric heads. Particular attention was paid to the relationships between the temporal branch, the galeal-fascial layers, and the fat pads of the temporal-zygomatic region. The temporal branch of the facial nerve pierces the parotidomasseteric fascia below the zygomatic arch. This branch travels first in the subcutaneous tissue and then, above the zygomatic arch, in the subgaleal space. The temporal branch divides into an anterior, a middle (frontal), and a posterior ramus soon after it pierces the parotid fascia. The course of the terminal twigs of the temporal branch of the facial nerve in the subgaleal space is extremely variable, with their location being at times posterior to the anterior one-fourth of the temporalis muscle. Occasionally, a twig for the frontalis muscle may run in between the two layers of the superficial temporal fascia. Because of these findings (anteroposterior variability of temporal branch twigs and recurrent intrafascial twig), Yasargils interfascial dissection may at times fail. A combined frontotemporal scalp/superficial temporal fascia dissection is anatomically suited to preserve the temporal branch of the facial nerve.

Petroclival meningioma. An attempt to define the role of skull base approaches in their surgical management.

BACKGROUND Petroclival meningiomas represent a difficult surgical challenge. The introduction of modern techniques of skull base surgery has stimulated the interest of the neurosurgical community in the surgical management of these lesions, although very good results have been obtained by experienced neurosurgeons in cases of petroclival meningioma operated using traditional surgical approaches. METHODS Thirty-one cases of petroclival meningioma have been operated on during a 4-year period using two different philosophies as far as the approach. Group A patients (13 cases) have been operated on using mostly either a subtemporal transtentorial or a retrosigmoid approach. Group B patients (18 cases) have been managed using a lateral skull base approach, either the anterior transpetrosal or the presigmoid approach. Translabyrinthine/transcochlear approaches have been used occasionally. RESULTS Tumor dissection and removal seemed to be easier in skull-base operated patients. However, operations take longer and surgical complications such as cerebrospinal fluid leak and hearing loss were increased. Radical tumor removal could be achieved in an equal percentage of cases of both groups (77% vs. 83%). The early postoperative course was more favorable in group B patients. However, late permanent morbidity appeared to be similar in the two groups of patients. CONCLUSIONS Skull base approaches facilitate tumor dissection and removal at the expense of increased surgical complications. However, the widened surgical field and increased angle of approach that the techniques of skull base surgery may offer can play a significant role in the removal of sizeable, infiltrative, and/or recurrent petroclival meningiomas.

Epidermoid Cysts of the Fourth Ventricle

Epidermoid tumors located in the fourth ventricle are exceedingly rare. Seven cases of this pathological condition were observed during a 10-year period. Patients were mostly middle-aged men, with a clinical history of relatively short duration (5 months). Clinical symptoms consisted of vertigo and ataxia, followed by incoordination, dysmetria, and tremor at a later stage. Computed tomography scanning represented the main diagnostic technique for these lesions, and typically showed a highly hypodense, round-shaped area within the fourth ventricle, occasionally accompanied by hydrocephaly. Subtotal surgical removal of the cysts produced excellent results in 86% of the cases. The implications of these findings are discussed.

The Endolymphatic SacMicrosurgical Topographic Anatomy

The endolymphatic sac is part of the membranous labyrinth; it plays an important role in the hearing mechanism. Injury to the endolymphatic sac may, over time, severely compromise hearing. The endolymphatic sac is located in a duplication of the dura of the posterior aspect of the petrous pyramid and is, therefore, in the surgical field of many neurosurgical operations performed on the posterolateral cranial base. The endolymphatic sac was exposed bilaterally in 10 anatomic specimens; the distance from the center of the sac to the posterior lip of the internal auditory meatus and to the XIth nerve in the jugular foramen was measured with a caliper. Also measured was the distance between the center of the sac and the closest point on the petrous ridge and the distance between that point and the petro-sigmoid intersection. The petro-sigmoid intersection was defined as the point at which the medial aspect of the sigmoid sinus intersects the lateral aspect of the petrous ridge. The dimensions of the sac were also recorded. On the average, the sac was found to be 15.7 mm posterosuperior (superolateral) to the XIth nerve in the jugular foramen (range, 11.0-18.5 mm) and 13.3 mm posterior (lateral) to the internal auditory meatus (range, 10.0-18.0 mm). The center of the sac was 24.1 mm (mean value) (range, 20.0-28.0 mm) in front of the petro-sigmoid intersection at a point 11.5 mm (mean value) (range, 8-17 mm) below the petrous ridge. The mean width and height of the sac were 3.83 (range, 2-6 mm) and 3.80 mm (range, 2.5-8 mm), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Cerebral vasospasm in a double-injection model in rabbit

The present study was designed to assess the occurrence of cerebral vasospasm following an experimental subarachnoid hemorrhage model in rabbits. Sixty-nine New Zealand albino rabbits were used in this study. One milliliter of fresh arterial blood was injected through the surgically exposed atlanto-occipital membrane over a period of 20 seconds. The procedure was then repeated 24 hours later. Fifty animals underwent digital subtraction angiography at one of the following prefixed intervals: 1, 3, or 8 days after the second injection hemorrhage. Nineteen animals underwent one angiographic examination prior to the instillation of the intracisternal blood. This procedure was followed by a repeated angiography 3 days after the second experimental subarachnoid hemorrhage. For the purpose of evaluation, the films were magnified 10-fold and the diameter of the basilar artery as well as that of the extracranial vertebral artery at three different levels were measured. We assessed the diameter of the basilar artery as well as the mean ratio extracranial vertebral artery/basilar artery diameters. This ratio was considered to minimize anatomical and technical variabilities. The results in the first 50 animals showed a trend suggesting that spasmogenic activity reaches a peak at about the third day after subarachnoid hemorrhage. These results were confirmed in the latter 19 animals. However, mortality in this group was high: 50%. This double-injection model of subarachnoid hemorrhage in rabbits consistently reproduced cerebral vascular spasm 3 days after repeated subarachnoid hemorrhage. However, its usefulness as an experimental model for subarachnoid hemorrhage is limited practically by the high animal mortality in the protocols where repeated angiographic studies are necessary.

Early postoperative MRI findings following surgery for herniated lumbar disc.

SummaryMRI is routinely used in the evaluation and management of patients with failed back surgery syndrome (FBSS). However, its value is unclear in the early detection of signs that can negatively affect the later course of surgical cases. The purpose of the present study is to describe the MR images of early postoperative MRI at 3 days in 30 unselected patients who underwent lumbar microdiscectomy, and to correlate the findings with follow up MRI at 8 weeks and with final outcome. The findings are correlated with literature data. Early postoperative MRI findings were consisting of pseudohernia in 24 patients (80%), annular rent in 23 patients (80%), and other non-specific postoperative findings. On the late MRI the pseudohernia persisted in 12 patients (50%), the annular rent in 4 patients (15%) and asymptomatic pseudo-spondylodiscitis was apparent in 3 patients (10%) as was a case of true spondylodiscitis. Therefore, early postoperative findings have limited value in the management of patients after surgery for lumbar disc herniation, since the images were not correlated with the immediate clinical course after surgery nor with the late radiological and clinical outcome. The evident imaging changes in the early postoperative period after lumbar disc surgery limit the accuracy of the interpretation of MRI examinations.

Preservation of the temporal branch of the facial nerve in pterional-transzygomatic craniotomy.

SummaryThe temporal branch of the facial nerve may be saved in a pterional-transzygomatic craniotomy if the dissection is carried beneath the superficial temporal fascia. The anatomical and technical aspects of this exposure are described in this report.

Choroid plexus papillomas in infancy and childhood

The present study deals with 15 cases of choroid plexus papilloma, out of approximately 500 cases of brain tumors observed in children up to 16 years old. Several features are considered, including clinical symptoms and signs—mostly related to increased intracranial pressure—radiological diagnosis, pathology and surgical treatment, and results. Surgery may be radical in most cases, with the exception of histologically malignant papillomas. The management results are usually satisfactory. An adequate choice of surgical approach is mandatory and surgical technique should be meticulous, also in order to avoid the risk of intraoperative tumoral seeding.

Early postoperative MRI findings following surgery for herniated lumbar disc. Part II : A gadolinium-enhanced study

SummaryThe aim of our study was to evaluate the contrast-enhanced MR imaging (MRI) findings, in the early postoperative period, in unselected patients undergoing lumbar microdiscectomy (15/16 had total resolution of their symptoms). Contrast-enhanced imaging studies were performed, in all 16 patients of our series, before surgery, and at the third postoperative day and, two months after surgery. Postoperative paraspinal muscles enhancement was present in all patients. In the postoperative period, nerve root enhancement was present in 5/16 patients at the early survey and persisted in one after two months. A pseudohernia depicted as epidural intermediate signal intensity tissue, was seen in 13 patients at the third day MRI, and only in eight after two months. This pseudohernia enhanced peripherally in 8/13 patients and enhanced homogeneously in the remaining five at the first postsurgical examination; in the late MRI the peripheral enhancement was appreciable in only two patients while a homogeneous enhancement was observed in six.Clinical symptoms resolved completely in 14/16 patients on clinical evaluation at the third postoperative day, while the remaining two patients showed residual symptoms and signs of radicular compression. At the early MRI these two patients showed intradural nerve root enhancement. Two months later, one patient did not show the previously described nerve root enhancement and improved clinically, while the other had a positive Straight Leg Raising Sign with persistent intradural nerve root enhancement. In conclusion, no correlation between clinical course and contrastenhancement of pseudohernia and extradural nerve root was appreciable, although intradural nerve root enhancement seems to represent a clinically relevant finding.

Microsurgical carotid endarterectomy in rats.

The purpose of this study was to develop an inexpensive experimental model of carotid endarterectomy. Unilateral common carotid endarterectomies 3 mm in length were performed on 25 rats using microsurgical techniques. The pattern of endothelial regrowth after endarterectomy, the pinocytosis of regenerated endothelial cells, and the effects of heparin and thromboxane A2 synthetase inhibitor on thrombus formation were examined 7 days after the resumption of flow. Pinocytotic vesicular transport in endothelial cells was evaluated using horseradish peroxidase. All endarterectomized vessels in both control and drug-treated groups were patent 7 days after operation without apparent mural thrombus formation. Regenerated endothelial cells had spindle-shaped nuclei and cell bodies with long axes oriented parallel to the direction of blood flow. There were several instances where the leading edge of the endothelium at the distal end was reflected back in the distal direction. The extent of the endothelial ingrowth was often greater from the proximal end of the endarterectomy than from the distal end. These observations suggest that hemodynamic force affects endothelial regeneration. Pinocytotic activity was less in the regenerated endothelium than in either the endothelium remaining at the periphery of the endarterectomy or the endothelium of the control animals.