Microsurgical management of anterior communicating artery aneurysms

OBJECTIVE

Aneurysms of the anterior communicating (ACOM) artery are the most frequently occurring type of ruptured intracranial aneurysms. The peculiar anatomy of the anterior communicating artery complex, its anatomic variations, and its multiple perforators, along with the deep location of these aneurysms and our difficulty accessing them, pose challenging anatomic problems in their surgical treatment.

METHODS

We present our operative techniques for microsurgical treatment of ACOM artery aneurysms. Special, complex situations that may arise during treatment of these aneurysms and their solutions are also discussed. We highlight the technical aspects of microsurgical clipping of ACOM artery aneurysms.

RESULTS

Operative videos are provided to illustrate the technical variations of approaching and clipping these aneurysms, the A3-A3 bypass technique, and the complexity of managing these aneurysms.

CONCLUSION

Attention to detail is critical for successful treatment of ACOM artery aneurysms. Management of each patient must be tailored, because no one technique is suitable for all situations. Not all ACOM artery aneurysms can be coiled; therefore, the surgeon's microsurgical clipping technique is an important facet of managing these aneurysms.

Outcomes of ruptured intracranial aneurysms treated by microsurgical clipping and endovascular coiling in a high-volume center

BACKGROUND AND PURPOSE

The purpose of this study was to analyze the 3-month outcomes of patients with aneurysmal subarachnoid hemorrhage (SAH) treated from January 2005 to June 2006. This paper describes the outcomes after treatment of aneurysmal SAH and comparison between patients treated by clipping or coiling in a high volume center.

MATERIALS AND METHODS

A retrospective chart review was performed of records of 195 consecutive patients with SAH. The overall outcome and the pretreatment variables predicting outcomes and the difference between the clipping and coiling groups were analyzed by logistic regression analysis.

RESULTS

A total of 105 (55%) patients had microsurgical clipping and 87 (45%) had endovascular coiling. At 3 months, 69% of patients recovered with no or mild disability. The predictors of a 3-month modified Rankin Scale (mRS) were Hunt and Hess (HH) grade on admission and the presence of intracerebral hemorrhage (ICH). Patients in the coiling group had worse admission grades; they had worse 3-month mRS (2.28 vs 1.73), but this was not significant when the groups were matched (P = .38). Vasospasm rate was significantly higher in the clipping group (66% vs 52%). The immediate incomplete occlusion rate of aneurysms was higher (21.7% vs 7.6%) in the coiling group.

CONCLUSION

The overall results of treatment of aneurysmal SAH have improved. There is no significant difference in the outcomes between the patients in the clipping and coiling groups.

The use of fibrin glue to stop venous bleeding in the epidural space, vertebral venous plexus, and anterior cavernous sinus: technical note

OBJECTIVE

Various techniques have been used to stop venous bleeding from the epidural space, vertebral venous plexus, and cavernous sinus. Here, we describe our experience with the use of fibrin glue to stop venous bleeding in these areas.

METHODS

During the last 8 years, the senior author (LNS) has used injection of Tisseel fibrin glue (Baxter Healthcare Corp., Deerfield, IL) into the epidural space (n = 200 patients), anterior cavernous sinus (n = 46 patients), vertebral venous plexus (n = 20 patients), and superior petrosal sinus (n = 20 patients) to assist in hemostasis. The technical nuances are illustrated in three videos.

RESULTS

Injection of fibrin glue in the epidural space, anterior cavernous sinus, and vertebral venous plexus yielded good results in assisting with hemostasis. Two patients experienced complications caused by occlusion of veins draining the brainstem after fibrin glue was injected into the superior petrosal sinus.

CONCLUSION

Fibrin glue injection is an excellent option for hemostasis in the epidural space, anterior cavernous sinus, and vertebral venous plexus. However, based on our experience, fibrin glue injection into the superior petrosal sinus is not recommended.

Petroclival meningiomas: multimodality treatment and outcomes at long-term follow-up

OBJECTIVE

To evaluate patients' clinical outcome, survival, and performance status, at the long-term follow-up evaluation after aggressive microsurgical resection of petroclival meningiomas.

METHODS

During a 13-year period (1991-2004), 150 patients underwent 207 operative procedures for resection of petroclival meningiomas. The tumor size was large in 79% of the patients, with a mean tumor diameter of 3.44 cm. Tumors extended into adjoining regions in 57% of the patients. Thirty patients (20%) previously underwent operation or irradiation. One hundred patients (66%) had a single operation, 43 patients (29%) had two operations, and seven patients (5%) had three operations. Gross tumor resection was accomplished in 48 patients (32%), subtotal resection in 65 patients (43%), and partial resection in 37 patients (25%). There were no operative deaths. Postoperative complications (cerebrospinal fluid leakage, quadriparesis, infections, cranial nerve palsies, etc.) were observed in 33 patients (22%). Postoperative radiation or radiosurgery was administered to 47 of the 102 patients who had residual tumors. The outcome and survival of patients were evaluated by questionnaires, telephone calls, and review of their recent radiological images.

RESULTS

At the conclusion of the study, 87 patients (58%) were alive with disease and 45 patients (30%) were alive without disease. The mean follow-up period was 102 months (range, 15-180 mo). Seven patients (5%; five of the subtotal and partially resected patients and two of the total resection patients) had recurrence; of these patients, two underwent repeat resection and four were treated with gamma knife radiosurgery. One of the patients died of tumor progression with no response to gamma knife radiosurgery. The recurrence-free survival rate was 100% at 3 years, 92.7% at 7 years, and 85% at 12 years; the progression-free survival rate was 96% at 3 years, 86.8% at 7 years, and 79.5% at 12 years. The Karnofsky Performance Scale score was 78 +/- 11 preoperatively, 76 +/- 11 at 1 year postoperatively, and 84 +/- 9 at the time of the latest follow-up evaluation. Common disabilities at the time of the follow-up evaluation included diplopia, loss of hearing, balance problems, and loss of sensation in the V1 and V2 cranial nerve distribution. Most patients developed coping mechanisms.

CONCLUSION

This series has the largest number of patients with the longest follow-up period, to our knowledge, reported in the literature to date. The excellent quality of life at the time of the long-term follow-up examination for these patients warrants aggressive but judicious tumor resection, with or without radiosurgical treatment of tumor remnants.

Do skull base lesions and their surgical treatment cause epileptic seizures?

OBJECTIVES

Few reports exist on the risk of seizures with skull base lesions and their surgical treatment.

PATIENTS AND METHODS

All patients referred for surgery of a skull base lesion at George Washington University Hospital from January 1998 to August 1999 were reviewed. After excluding patients with other risk factors 136 patients were included.

RESULTS

No seizures were reported before or after surgery, but 59 patients (43%) were taking anticonvulsants. Only 17 (12.5%) had EEG. Four of these showed no abnormalities, 2 were abnormal without sharp waves and 11 had sharp waves (an increase compared to the general population). Most sharp waves affected the temporal lobe on the side of surgery. All EEGs were performed less than 4 months after surgery.

CONCLUSION

This study does not indicate that seizures are common in this patient group, but there was an increased amount of epileptiform activity on EEG and many patients were taking AED. A prospective study with systematic patient interviews, pre- and post-surgical EEG and a longer follow up is needed.

High-flow Bypass Grafts in the Management of Complex Intracranial Aneurysms

THE MAJORITY OF intracranial aneurysms can be treated by either endovascular coiling or microsurgical clipping. A small group of aneurysms may require vascular bypass or reconstruction for their management. A variety of vascular reconstruction techniques are available, including direct suture, patch grafting, local reimplantations, side to side anastomosis, and bypass grafts. Bypass grafts may include low-flow (superficial temporal to middle cerebral) and high-flow bypass grafts using either the radial artery or saphenous vein. In this article, the indications and techniques of high-flow bypasses and concurrent aneurysm management are discussed. Troubleshooting of these bypasses is also illustrated. Seven intraoperative videos have been provided to demonstrate the various techniques of radial artery graft harvesting, cervical exposure of carotid vessels, bypasses, and concurrent aneurysm management.

Intradural cranial chordoma: a rare presentation of an uncommon tumor

Object

Intracranial intradural chordomas are extremely rare lesions, and only a few cases have been reported in the neurosurgical literature. The authors performed a retrospective analysis of cases treated at their institutions. They present an illustrative surgical scenario and discuss the published literature, pathogenesis, and histopathological features as well as available follow-up data on the clinical behavior of these intradural lesions.

Methods

The authors reviewed clinical, neuroimaging, operative and follow-up data from a series of 79 chordomas treated at their institutions over the last 17 years. They found that the tumors were confined exclusively to the intradural compartment in only three cases. Staining for MIB-1 was performed to support the differential diagnosis between ecchordosis physaliphora and intradural chordoma, and in all three patients the neoplastic nature of the lesions was confirmed. None of these three cases showed recurrence of the lesion at midterm follow up.

Conclusions

Complete resection, followed by close clinical and neuroradiological follow up, is warranted in cases of intradural cranial chordoma.

Patient Outcome at Long-term Follow-up after Aggressive Microsurgical Resection of Cranial Base Chordomas

OBJECTIVE:

In this study, we evaluated patients' clinical outcome and recurrence rates at long-term follow-up after aggressive microsurgical resection of cranial base chordomas.

METHODS:

Seventy-four patients with chordomas underwent operations during a 16-year period from 1988 to 2004. The philosophy was to perform complete resection whenever possible and to provide adjuvant radiotherapy for remnants. Staged operations were performed for extensive tumors or if a sizable tumor remnant was noted after the first resection. Patients included primary (previously untreated) and previously operated or irradiated cases. Information was prospectively gathered concerning the patients' neurological condition, Karnofsky Performance Scale score, and tumor status on magnetic resonance imaging scans.

RESULTS:

There were 47 primarily operated patients (63.5%) and 27 patients (36.5%) who had previously undergone surgery or radiotherapy. A total of 121 procedures were performed in 74 patients. The mean follow-up period was 96 months, with a range of 1 to 198 months. A single stage removal was performed in 41 (55.4%) of the patients and multiple stage removal was performed in 33 (44.5%) of the patients. Gross total removal was accomplished in 53 (71.6%) of the patients, and subtotal resection was accomplished in 21 (28.4%) of the patients. During the follow-up period, 24 (32%) of the patients had no evidence of disease, 37 (50%) of the patients were alive with evidence of disease, 11 (14.8%) of the patients died of disease, and two (2.7%) of the patients died of complications. Recurrence-free survival at 10 years was 31% for the whole group, 42% for the primarily operated patients, and 26% for the reoperation cases (P = 0.0001). The average Karnofsky Performance Scale score was 80 ± 11.7 preoperatively, 84 ± 8.9 at the 1-year follow-up, and 86 ± 12.8 at the last follow-up in surviving patients. No conclusion could be drawn regarding the value of radiotherapy because of the treatment philosophy and the small number of patients.

CONCLUSION:

Aggressive microsurgical resection of chordomas can be followed by long-term, tumor-free survival with good functional outcome. A more conservative strategy is recommended in reoperation cases, especially after previous radiotherapy, to reduce postoperative complications.

Patient outcome at long-term follow-up after aggressive microsurgical resection of cranial base chondrosarcomas

OBJECTIVE

To evaluate patient clinical outcome and survival at long-term follow-up after aggressive microsurgical resection of chondrosarcomas of the cranial base.

METHODS

Over a 20-year period, 47 patients underwent 72 operative procedures for resection of cranial base chondrosarcomas. Thirty-three patients were previously untreated, whereas 14 patients previously had undergone surgery or radiation. Twenty-three patients had a single operation and 24 underwent staged (more than one) operations because of extensive disease. Patients who underwent subtotal resection also underwent radiotherapy or radiosurgery. Patients were evaluated at follow-up clinically and by imaging studies.

RESULTS

Gross total resection was accomplished in 29 (61.7%) patients, and subtotal resection was accomplished in 18 patients (38.3%). The resection was better in patients who underwent a primary operation (gross total resection, 68.8 versus 46.7%) rather than a reoperation. Patients who underwent incomplete resection underwent postoperative radiotherapy, which included proton beam radiotherapy (15.6%), radiosurgery (68%), and fractionated radiation (15.6%). There were no operative deaths. Postoperative complications (cerebrospinal fluid leakage, quadriparesis, infections, cranial nerve palsies, etc.) were observed in 10 patients (18%). The follow-up ranged from 2 to 255 months, with an average of 86 months. At the conclusion of study, 36 (76.6%) patients were alive, and 21 (44.7%) patients were alive without disease. Recurrence-free survival was 32% at 10 years in all patients, 42.3% in primary patients and 13.8% in those who underwent reoperation. The Karnofsky performance score was 82.4 +/- 9.8 before surgery, 85 +/- 12.5 at 1 year after surgery, and 85.3 +/- 5.8 at the latest follow-up. Two patients died as a result of radiotherapy complications (malignancy, radiation necrosis).

CONCLUSION

Cranial base chondrosarcomas can be managed well by complete surgical resection or by a combination of surgery and radiotherapy. The study cannot comment about the efficacy of radiotherapy. Approximately half of the patients survived without recurrence at long-term follow-up (>132 mo). The functional status of the surviving patients was excellent at follow-up.

Endoscopic Microneurosurgery: Usefulness and Cost-effectiveness in the Consecutive Experience of 210 Patients

OBJECTIVE:

Indications, usefulness, and cost-effectiveness of the endoscope in routine microneurosurgery are not clear. To delineate such aspects, we assessed our experience of endoscopic application and additional cost to use an endoscope.

METHODS:

Endoscopes were used in 210 patients with cranial base and cisternal pathological features in the previous 7 years. Lesions were located in the extradural cranial base in 78 patients and in the cistern in 132 patients. Rigid lens endoscopes 2.7 to 4 mm in width, 11 to 20 cm in length, and 0 to 70° in angle were used.

RESULTS:

Endoscopes were used for primary or a significant part of the surgery in 64% of the extradural cranial base procedures. Although endoscopes were used only for visual assistance in 82% of cisternal pathological features, significant benefit was noted in 9% and was not different from cranial base lesions. Eleven patients may have had complications if the endoscope had not been used, and 10 procedures would have been impossible without endoscopic use. Therefore, the number of patients need to treat to experience significant benefits by endoscope was 10. Endoscopic equipment costs an additional US $326 per patient and, hence, significant benefit was the equivalent of US $3260. No permanent complications resulted from the use of the endoscope.

CONCLUSION:

The endoscope can be applied safely in routine microsurgery with specific equipment and has proven useful in 1 of 10 patients. To perform more effective procedures using endoscopes, we need to develop specially designed instruments usable through a narrow corridor and in an angled field.

Reconstruction Options for Complex Middle Cerebral Artery Aneurysms

OBJECTIVE:

To describe techniques of reconstruction for unclippable and uncoilable middle cerebral artery aneurysms.

METHODS:

A retrospective review was performed of seven patients who underwent eight operations during a 9-year period to treat complex middle cerebral artery bifurcation aneurysms not amenable to direct clipping or endovascular coiling. All preoperative and postoperative clinical and imaging data were reviewed. Follow-up was obtained for all patients via clinic visit and/or telephone.

RESULTS:

The operative techniques used included saphenous vein graft bypass (n = 1), radial artery graft interposition (n = 2), radial artery patch (n = 1), superficial temporal artery interposition graft (n = 1), superior thyroid artery interposition graft (n = 1), direct reimplantation of branch (n = 1), and reconstruction of trifurcation (n = 1). There was no mortality. Six patients had excellent outcomes with Glasgow Outcome Scale scores of 5, and one patient had a good outcome with a Glasgow Outcome Scale score of 4.

CONCLUSION:

Techniques for middle cerebral artery reconstruction may remain important and useful in the age of endovascular aneurysm treatment.

Proposed Classification of Segments of the Internal Carotid Artery: Anatomical Study With Angiographical Interpretation

The nomenclature and borders of the segments of the internal carotid artery (ICA) remain confusing. A classification of segments of the ICA is proposed based on constant anatomical structures, such as the carotid foramen and canal, the petrous bone, the petrolingual ligament (PLL), and the proximal and distal dural rings. The bilateral ICAs were dissected in 15 cadaveric head specimens using different neurosurgical approaches. The bilateral lacerum foramina were studied in five dry skulls. The bilateral segments of the ICA were also examined on carotid angiograms of 10 normal patients and another with the ophthalmic artery originating from the intracavernous portion of the ICA. The present classification divides the ICA into five segments in the direction of the blood flow. The cervical segment is extradural and extracranial, the petrous segment is extradural and intraosseous, the cavernous segment is interdural and intracavernous, the clinoidal segment is interdural and paracavernous, and the cisternal segment is intradural and intracisternal. The ICA did not pass through the lacerum foramen in any specimen. In all specimens, 1/8 to 5/8 of the lacerum foramen was under the deep dural layer of the cavernous sinus. The term 'lacerum segment' as used previously and called the 'trigeminal segment' by us cannot be justified. The PLL is the posterolateral border of the cavernous sinus and the lacerum and trigeminal segments should be included in the cavernous and petrous segments. The ophthalmic artery may originate from the clinoidal ICA, from the cavernous ICA, or from the middle meningeal artery. Instead of using the term 'ophthalmic segment,' the term 'cisternal segment' should be used for the anatomically distinct ICA in the subarachnoid space. This classification should be minimally affected by anatomical variations.

Bypass Grafting and Revascularization in the Management of Posterior Circulation Aneurysms

OBJECTIVE:

To describe the bypass techniques, cranial base approaches, results of treatment, causes of failure, and lessons that are learned in patients with posterior circulation aneurysms requiring revascularization.

METHODS:

Retrospectively, 19 patients with posterior fossa aneurysms requiring revascularization procedures operated on between 1991 and 2002 were reviewed. Preoperative and postoperative clinical information, neurological examinations, imaging data, and updated follow-ups were reviewed. Patient outcome is reported as the most current Karnofsky Performance Scale score.

RESULTS:

A total of 22 arterial bypasses were performed in 19 patients for posterior fossa circulation aneurysms between 1991 and 2002. The mean follow-up was 41 months. Total graft patency rate (including patients requiring reoperation) was 86.4% (before) and 100% (after) salvage procedures. Patient outcome was 84.2% with Karnofsky Performance Scale score 80 to 90, and three deaths occurred perioperatively. Only one death could be attributed to the failure of the radial artery graft because of spasm and subsequent rupture during angioplasty.

CONCLUSION:

Certain graft selection criteria and technical considerations contribute to the success or failure of bypass grafts in the management of posterior circulation aneurysms. Bypass procedures remain an important method of management of complex posterior circulation aneurysms, in addition to endovascular procedures.

The trigeminal nerve and ganglion: an anatomical, histological, and radiological study addressing the transtrigeminal approach

BACKGROUND

The transtrigeminal route with splitting of the trigeminal ganglion (TG) is a skull base approach used to expose the posteromedial part of the cavernous sinus (CS), the base of the TG, and the petrolingual ligament (PLL).

METHODS

To verify the transtrigeminal approach (TTA), the 3 divisions of the trigeminal nerve (TN), the so-called TG, and the trigeminal root were analyzed anatomically, histologically, and radiologically. The anatomic study was performed bilaterally in 5 cadaveric head specimens. For the histologic study, 6 TN specimens removed from cadavers were used. In addition, the radiologic demonstration of the TN and its so-called ganglion was performed on 5 cases by magnetic resonance imaging (MRI) scan.

RESULTS

The TN is composed of linear, crossing, and connecting rootlets. These 3 types of rootlets indicate a plexiform constitution rather than a ganglion even though there are ganglionic cells. Consequently, the term "trigeminal plexus" may be preferred to describe this network. In our new proposed classification, the segments of the TN can be divided into 6 portions according to their relationship with the brainstem, the cisterns, and the bone structures. The first 3 segments before separating into 3 divisions are (1) pontine, (2) cisternal (preganglionic or preplexal), (3) gasserian (ganglionic or plexal). The last 3 segments after the division are (4) preforamino-fissural (postganglionic or postplexal), (5) foramino-fissural, and (6) extracranial (postforamino-fissural). A loose connective tissue along the rootlets of the maxillary and the mandibular divisions of the TN at the gasserian (ganglionic or plexal) segment enabled us to split the so-called "trigeminal ganglion" or "gasserian ganglion" to perform the TTA.

CONCLUSION

The TTA is possible, useful, and necessary in selected cases with invasion of the posteromedial part of the CS.

Endoscope-assisted Microsurgery for Microvascular Compression Syndromes

OBJECTIVE

To discuss the results of endoscope-assisted surgery in microvascular decompression (MVD) of Cranial Nerves (CNs) V, VII, and VIII.

METHODS

Neuroendoscopy was used as an adjunct to the surgical microscope in the MVD of the trigeminal (17 patients), facial (10 patients), and vestibulocochlear (1 patient) nerves in a series of 28 consecutive patients. After a standard microsurgical approach to CNs V, VII, and VIII, the endoscope was used to inspect all aspects of neural anatomy, to assess vascular compression, and to check the results of the decompression. Endoscope use was graded in four categories: Grade I, used but no definite role; Grade II, visualization assisted; Grade III, procedure assisted; and Grade IV, primary role. The usefulness of the endoscope was evaluated in each case.

RESULTS

The endoscope was useful in visualizing the anatomy in all cases. It was especially useful in establishing trigeminal vein compression of CN V in Meckel's cave; observing multiple sources of vascular compression; ensuring adequate decompression after cauterization of vein, insertion of the Teflon felt, or a pexy procedure; and permitting observation of the compression of CN VII at the root exit zone by small arteries and veins. In six patients with trigeminal neuralgia, the trigeminal vein was cauterized and divided by using endoscopic vision only because the venous compression was not completely visualized with the microscope. During a follow-up period of 6 to 52 months (mean, 29 mo; median, 40 mo), all patients were asymptomatic and receiving no medication.

CONCLUSION

The endoscope is a useful adjunct to MVD in the treatment of trigeminal neuralgia, hemifacial spasm, and disabling positional vertigo or tinnitus.

Endoscopic and Microscopic Extended Subfrontal Approach to the Clivus: A Comparative Anatomical Study

Ten cadaveric heads fixed and injected were dissected in the operative position. An enlarged subfrontal approach was adopted. The clival bone was drilled as much as possible under direct microscopic vision. Dissection in blind angles was avoided until the clival dura was exposed. The rigid 4-mm endoscope (angled 0 degrees and 30 degrees) was secured in a holder so the surgical cavity could be inspected. The residual bone was drilled under endoscopic visualization. The amount of bone removed was measured and compared with that removed under microscopic view. Blind angles in both microscopic and endoscopic views were recorded. The additional area of clival bone removed under endoscopic visualization compared with microscopic visualization was 467 mm(2) (range, 176 to 753 mm(2); standard deviation, 208.8 mm(2)).The amount of additional bone removed under endoscopy was inversely and significantly related to the minimal distance between the vertical segment of the two cavernous carotid arteries (p = 0.04). The endoscope is of great value in the removal of clival bone through the extended subfrontal approach. Its use improves the visualization of angles that are blind under the microscope.

Endoscope-assisted microsurgery for intracranial aneurysms

OBJECTIVE

We discuss the role of the endoscope in the microsurgical treatment of intracranial aneurysms, analyzing its benefits, risks, and disadvantages.

METHODS

This was a prospective study of 55 patients with 79 aneurysms, treated between July 1998 and June 2001, for whom the endoscope was used as an adjunct in the microsurgical treatment of their lesions. Seventy-one aneurysms were located in the anterior circulation, and eight were located in the posterior circulation. Thirty-seven patients presented with subarachnoid hemorrhage. Eighteen patients had unruptured aneurysms, of whom 5 presented with mass effect, 2 presented with transient ischemic attacks, and 11 were without symptoms. In all cases, the endoscope was used in addition to microsurgical dissection and clipping (sometimes before clipping, sometimes during clipping, and always after clipping), for observation of the neck anatomic features and perforators and verification of the optimal clip position. Intraoperative angiography was performed for all patients after aneurysm clipping.

RESULTS

In the majority of cases, the endoscope was very useful for the assessment of regional anatomic features. It allowed better observation of anatomic features, compared with the microscope, for 26 aneurysms; in 15 cases, pertinent anatomic information could be obtained only with the endoscope. The duration of temporary clipping of the parent artery was significantly reduced for two patients. The clip was repositioned because of a residual neck or inclusion of the parent vessel during aneurysm clipping in six cases, and the clip position was readjusted because of compression of the optic nerve in one case. One patient experienced a small aneurysm rupture that was directly related to use of the endoscope, but this was easily controlled, with no sequelae. For many patients, the combination of the neuro-endoscope and the micro-Doppler probe made intraoperative angiography redundant.

CONCLUSION

"Endoscope-assisted microsurgery" is a major advance in the microsurgical treatment of intracranial aneurysms; the endoscope allows better observation of regional anatomic features because of its magnification, illumination, and ability to "look around corners."

Outcome analysis of preoperative embolization in cranial base surgery

OBJECTIVE

Management of cranial base tumors requires an interdisciplinary approach. Supraselective angiography and embolization is an important adjunct to cranial base surgery. Though successful embolization facilitates resection, the morbidity of this procedure remains poorly defined. Therefore, we set out to define the morbidity associated with embolization of skull base meningiomas, thus allowing for informed decision making when considering this adjunct to tumor resection.

METHODS

A retrospective analysis was performed on our experience with embolization of 167 cranial base meningiomas. Cranial base meningiomas were defined as tumors originating from the olfactory groove, tuberculum sella, medial sphenoid wing, petro-clival region or foramen magnum.

RESULTS

280 feeding vessels were embolized with an average of 1.7 vessels per lesion. In 91% of patients embolized, good to excellent embolization was achieved without permanent neurological sequelae. In 20 patients no embolization was attempted due to the risk of new neurologic deficits or lack of an appropriate vessel for embolization. Twenty-one patients (12.6%) had transient worsening of their neurologic exam or a medical complication requiring hospitalization. Fifteen patients (9%) experienced permanent neurologic deficits or medical morbidity as a result of embolization. Four of the patients who experienced major complications had a decline in previously compromised cranial nerve function.

CONCLUSIONS

Embolization of cranial base tumors is an important part of the therapeutic armamentarium for the treatment of cranial base lesions. Recognition of the morbidity of this procedure will allow for the most appropriate use of this powerful adjunct to cranial base surgery.

The cosmetic aspects of neurosurgery

The cosmetic aspects of neurosurgery are important and make a considerable difference to the patient's quality of life. In general, the saying is true that "at a cocktail party, the patient should not be recognized as having had neurosurgery, or, even better, the patient's own neurosurgeon should not be able to detect which side the patient was operated on when the patient is seen in the office 6 months later without looking at the chart."

The preservation and reconstruction of cerebral veins and sinuses

Although cerebral veins and venous sinuses are very important to the neurosurgeon, they have received adequate attention only recently. The consequences of cerebral venous occlusion are well known. When the venous outflow is compromised due to a lack of adequate collateral circulation, venous infarction follows, with swelling, haemorrhage and neuronal death. The clinical consequences will depend upon the region of involvement of the brain and the site of the infarcted tissue. The symptoms may include seizures, hemiplegia, aphasia, coma and death. Similarly, the consequences of cerebral venous sinus occlusion depend upon the availability of collateral circulation. When such collaterals are not available, papilledema and visual loss and a pseudotumour cerebri syndrome are observed in milder cases, whereas, severe diffuse brain swelling, coma and death may be observed in severe cases. Acute venous or venous sinus occlusion is potentially very dangerous, whereas slow and chronic venous or venous sinus occlusion is better tolerated. Even in such patients, some neurological manifestations may follow, when the collaterals are poor.

Endoscopic-assisted transcolumellar approach to the clivus: an anatomical study

OBJECTIVE

Surgical exposure of the clivus and retroclival region is a challenging problem. Several extracranial and intracranial approaches using microsurgical techniques have been proposed in the search to optimize the exposure of the clival region. The objective of the present study was to develop an endoseopic-assisted transcolumellar approach to the anterior clivus.

STUDY DESIGN

Experimental anatomic study.

METHODS

The approach was studied in 10 consecutive cadaveric preparations. It included a preliminary external rhinoplasty technique with a septal displacement procedure, which gives a wide intranasal route to the posterior wall of the nasopharynx. By use of a drill system and instruments specially designed for endoscopic sinus surgery, the clivus and retroclival region were appropriately managed. Direct morphometric measurements were obtained during all steps of the procedure.

RESULTS

The endoscopic-assisted transcolumellar approach developed in the present experimental study allowed a good exposure of the clivus area and anterior cranial-cervical junction. By performing a preliminary septoplasty, the nostrils were turned into a single passage with adequate space for endoscopic insertion and manipulation of one or two instruments. The authors were able to completely expose the posterior wall of the sphenoid sinus and clival dura after the thick bone of the vomer, the floor of the sphenoid, and the clivus were removed by a drill. Angled endoscopes provided a comprehensive view of the retrosellar area.

CONCLUSIONS

The endoscopic-assisted transcolumellar approach, besides offering a wide opening for endoscopic management of the clivus, also allowed the surgeon to perform a double-handed procedure and to associate the use of a microscope if needed. The use of endoscopes, although lacking the three-dimensional view, gave a thorough and closer exposure of the surgical field with the advantage of a multiangled perspective.

Patient-evaluated outcome after surgery for basal meningiomas

OBJECTIVE

To study the outcomes of patients with basal meningiomas treated by one primary surgeon with a philosophy of aggressive surgical management to establish an index of satisfaction and patient-evaluated outcome.

METHODS

We collected prospective data for patients with basal meningiomas who were operated on by one primary surgeon (LNS) during a 7-year period from 1993 to 2000. The outcomes in 269 patients were ascertained through follow-up visits, mailed follow-up questionnaires, and telephone interviews by two other surgeons (RA and MN). The mean patient age was 50 +/- 13.6 years. The mean estimated tumor diameter was 3.07 +/- 1.24 cm. There were 62 males and 207 females. Mean follow-up was 49 +/- 26 months. Twenty-seven percent of patients were Levine-Sekhar (LS) Grade 0, 43% were LS Grade I, 24% were LS Grade II, and 6% were LS Grade III. Gross total resection was achieved in 66% of patients. Extent of resection correlated (P < 0.05) with LS grade. Thirty-seven patients received adjuvant treatments, and six patients required reoperations. Perioperative mortality was 1.1%. Eighty percent of patients were discharged home, 17% were discharged to rehabilitation facilities, and 1.5% were discharged to nursing homes. Postoperative complications were observed in 30% of patients.

RESULTS

During the follow-up study, of a total of 269 patients, 30 patients could not be contacted, and 11 patients had died of unrelated causes. The mean follow-up Karnofsky Performance Scale score of the patients was 83 +/- 10. Ninety-seven percent of patients were very satisfied/satisfied with their treatments (P < 0.001). Forty-three percent of patients were employed, and 83% of patients were employable. Their expectations of treatment were met in 90% of patients (P < 0.001), 95% thought surgery had been a good treatment choice (P < 0.001), and 95% would recommend the same treatment for a family member (P < 0.001).

CONCLUSION

These results demonstrate that patient satisfaction can remain high and satisfactory outcome can be achieved with surgical management in patients with these complex lesions.

Brain stem cavernoma excised by subtemporal-infratemporal approach

Brain stem cavernomas are most safely removed through the pial surface at which the cavernoma is surfacing. When a lower pontine or an upper medullary cavernoma comes to the surface of the anterior portion of the brain stem, it is difficult to reach by traditional approaches. We describe a case of mid- and lower pontine cavernoma, surfacing anteriorly, which was completely excised by the subtemporal-infratemporal approach. After making a small temporal craniotomy and a zygomatic osteotomy, the petrous carotid artery was mobilized anteriorly and the petroclival bone was drilled away to reach the anterior surface of the pons using the subtemporal-infratemporal approach. A small incision was made on the anterior surface of the pons, between the CN V and CN VI and the cavernoma was completely excised with the aid of the surgical microscope and the neuro-endoscope. Immediately after the operation, the patient had a complete abducens palsy and a mild increase of left hemiparesis, both of which resolved completely within 3 months. The patient returned to the full time work without any neurological deficit. A follow-up MRI 1 year later showed the complete excision of the cavernoma. The subtemporal-infratemporal approach is useful for anteriorly located mid to lower pontine and upper medullary cavernomas.

Nonvestibular schwannomas of the brain: a 7-year experience

OBJECTIVE

Nonvestibular schwannomas are uncommon tumors of the brain. Trigeminal nerve schwannomas are the most common of this group, followed by glossopharyngeal, vagal, facial, accessory, hypoglossal, oculomotor, trochlear, and abducens nerve schwannomas, in descending order of frequency. We present a series of nonvestibular schwannomas that were surgically treated during a 7-year period.

METHODS

Forty-six patients with schwannomas of Cranial Nerves V (26 cases), VII (7 cases), IX, X, and XI (9 cases), XII (3 cases), and III (1 case) were microsurgically treated by the senior author (LNS) during a 7-year period, from 1993 to 2000. The clinical presentations, operative approaches, complications, and results were studied.

RESULTS

Forty-five patients underwent gross total tumor resection in the first operation. One patient who had undergone subtotal tumor resection in the initial operation experienced a large recurrence after 4 years, and gross total tumor resection was achieved in the second operation. There were no postoperative deaths. Postoperative morbidity consisted of cerebrospinal fluid leaks for 5 patients (3 patients required a second operation to repair the leak, and 2 patients responded to lumbar drain placement), meningitis for 3 patients (2 cases were aseptic and 1 involved bacterial meningitis, which resolved with antibiotic therapy), vasospasm requiring angioplasty for 1 patient, temporary hemiparesis for 2 patients (who experienced good recoveries), and permanent hemiparesis for 1 patient. New cranial nerve deficits were observed for 24% of patients but were usually partial. The mean follow-up period was 33.3 months (range, 0.2-93 mo). No patient experienced tumor recurrence after complete tumor removal. The patient who experienced regrowth of the tumor did not exhibit recurrence after the second operation. The Karnofsky Performance Scale scores at the latest follow-up examination were 80 or more for 45 patients (98%) and 70 for 1 patient.

CONCLUSION

Nonvestibular schwannomas can be treated via microsurgical excision, with excellent functional results. Recurrence is rare after total tumor excision, although much longer follow-up monitoring is required.

Cerebral revascularization for aneurysms and tumors

OBJECTIVE

To discuss the indications, techniques, pitfalls, complication avoidance, and management of cerebral revascularization techniques for the treatment of aneurysms and cranial base tumors.

METHODS

The indications for cerebral revascularization procedures included microsurgical occlusion of a parent vessel during the treatment of aneurysms and occlusion of a major vessel during the treatment of basal tumors. The techniques discussed include arterial patch grafting, end-to-end anastomosis, side-to-side anastomosis, arterial interposition grafting, and extracranial-to-intracranial bypass grafting, using radial artery grafts or saphenous vein grafts.

RESULTS

During the 15-year period between 1985 and 2000, the senior author performed 24 radial artery grafts, 105 saphenous vein grafts, and 8 other revascularization procedures, among 50 patients with aneurysms and 83 patients with cranial base tumors. The overall patency rate was 95.6%. Twenty-three patients experienced a cerebral infarction; among those patients, 17 (12.5%) exhibited symptoms but the majority demonstrated considerable recovery during the follow-up period. One hundred one patients recovered to an excellent (Glasgow Outcome Scale score of 5) or good (Glasgow Outcome Scale score of 4) condition. Fifteen patients died as a result of recurrence or progression of tumors during the follow-up period. There were five perioperative deaths. For the last 35 patients, the surgical mortality rate was 0%, with all patients returning to an excellent or good condition.

CONCLUSION

Although highly specialized, these sophisticated cerebral revascularization techniques should be learned and practiced by all neurosurgeons who wish to microsurgically treat intracranial aneurysms or cranial base tumors.

Cutaneous metastasis from an intracranial glioblastoma multiforme

A 34-year-old white man with a history of an intracranial glioblastoma multiforme was treated with surgical excision and radiotherapy. Five months later, the patient had a rapidly growing scalp mass develop. This lesion was excised, and the histology revealed a tumor that was similar to the originally resected intracranial glioblastoma. Immunohistochemistry for general neuroepithelial derivation (S-100 protein) and for glial fibrillary acidic protein (GFAP) was positive, whereas mesenchymal, epithelial, and neuronal markers were negative. This immunohistochemistry pattern was identical to the original tumor. Although metastasis of this tumor is not uncommon, metastasis to the skin has never been reported. To our knowledge, this is the first reported case of cutaneous metastasis from glioblastoma in the world literature.

Brain-stem abscess successfully treated by microsurgical drainage: a case report

Brain-stem abscess is an uncommon condition associated with high mortality. The best method of treatment is not yet defined. It can be managed by medical treatment alone, stereotactic aspiration of the pus and medical treatment, or surgical excision/drainage of the abscess. We present a case of large brain-stem abscess, treated successfully by surgical drainage after the failure of medical treatment. The patient had a large brain-stem abscess extending from the mid-brain down to the lower pons. She was in a poor neurological condition pre-operatively, and was worsening despite intravenous antibiotics. The abscess was coming close to the surface in the lateral aspect of the mid-brain. The presumed source of infection was multiple dental abscesses. The brain-stem abscess was approached by a subtemporal transzygomatic approach and drained completely after making an incision on the lateral surface of the mid-brain. After the operation, the patient showed steady improvement. At six months after the surgery, the patient was fully conscious, talking fluently, and walking with the help of a walker. Her hemiparesis and co-ordination were improving. Surgical drainage of a brain-stem abscess is indicated when medical therapy fails. Proper anatomical knowledge of the brain-stem and the selection of appropriate surgical approach is important for safe drainage of the abscess.

Cerebral revascularization using radial artery grafts for the treatment of complex intracranial aneurysms: techniques and outcomes for 17 patients

OBJECTIVE

The goal of this report is to illustrate the use of radial artery grafts as bypass conduits in the management of complex intracranial aneurysms and to describe a new "pressure distension technique" to eliminate postoperative vasospasm, which was a common problem early in our experience.

METHODS

This study included a series of 17 patients who were surgically treated between 1994 and January 2001 for complex intracranial aneurysms. Five patients were surgically treated without the pressure distension technique; for 12 patients, the technique was used to reduce postoperative vasospasm. Fourteen of the patients had anterior circulation aneurysms, and three had posterior circulation aneurysms. Five of the patients had undergone previous attempts at direct clipping or excision and reconstruction of the aneurysm in question, and embolization had been performed for one patient with a carotid-cavernous fistula. Thirteen patients underwent permanent revascularization combined with proximal occlusion, trapping, or clipping, and four patients underwent temporary revascularization for cerebral protection during anticipated prolonged occlusion of the parent vessel during aneurysm dissection. Surgical techniques are described, with particular reference to vessel collection and bypass techniques.

RESULTS

The outcomes for this group of patients, considering the complexity of the aneurysms and their "inoperability," with respect to direct clipping, were satisfactory. The aneurysms were completely obliterated for all patients, and the grafts were patent for all except one patient on postoperative angiograms. There were two deaths, one attributable to systemic sepsis and the other attributable to cardiac arrest during a transbronchial biopsy. The postoperative Glasgow Outcome Scale scores were either better or the same for all other patients, compared with their preoperative scores. Three of the five patients treated before the institution of the pressure distension technique experienced vasospasm of the graft, with two of those patients requiring angioplasty. For one of those patients, angioplasty led to rupture of the graft. Vasospasm was not observed for any of the 12 patients for whom the pressure distension technique was used. We observed no morbidity related to radial artery collection.

CONCLUSION

Revascularization techniques are occasionally necessary for the surgical treatment of complicated intracranial aneurysms. The merits of the use of the radial artery as a bypass conduit are discussed. Radial artery grafts should be considered as alternatives to saphenous vein and superficial temporal artery grafts. The problem of vasospasm of the artery has been solved with the pressure distention technique.

Dural reconstruction with fascia, titanium mesh, and bone screws: technical note

OBJECTIVE

After the resection of cranial base tumors, there may not be enough free dural margin left for reconstruction after involved bone and dura have been removed. In such a situation, dural reconstruction becomes a problem. We propose a new technique of dural closure in such cases.

METHODS

A fascial graft is prepared from either fascia lata, abdominal fascia, pericranium, or temporal fascia and is trimmed to a size slightly larger than that of the dural defect. The fascial graft is placed over the dural defect and affixed to the underlying bone with a piece of titanium mesh, titanium screws, or both. The graft is then reinforced with fibrin glue.

RESULTS

This method of dural reconstruction has been used in five patients with basal meningiomas. Three were in the petromastoid area, and two were in the planum-ethmoid area. None of these patients experienced postoperative cerebrospinal fluid leak, and none experienced any complications related to the reconstruction.

CONCLUSION

This technique of dural reconstruction can be used in selected cases of basal tumors without enough free dural margin to sew into a fascial graft.

Cerebral revascularization in cranial base tumors

Certain cranial base tumors may involve intracranial arteries by encasement or invasion. In such patients, resection of the tumor along with the involved artery is an option for treatment. Techniques and results of vascular bypasses for such lesions are discussed in this article.

Posterior fossa meningiomas: surgical experience in 161 cases

BACKGROUND

We report the clinical, radiological, and surgical findings of patients with posterior fossa meningiomas surgically treated at our institution over the last 6 years.

METHODS

We reviewed 161 consecutive cases of posterior fossa meningiomas operated on between April 1993 and April 1999 at The George Washington University Medical Center.

RESULTS

There were 128 female and 33 male patients (mean age 47 years, range of 10-81 years). Meningiomas were classified as petroclival (110 cases), foramen magnum (21 cases), cerebellar hemispheric, lateral tentorial (14 cases), cerebellopontine angle (9 cases), and jugular foramen (7 cases). Mean tumor equivalent diameter (TED) = (D1xD2xDE)(1/3) was 3.1 cm (range of 0.53-8.95). Head pain (50% of cases) and disturbance of gait (44%) were the most common presenting symptoms, and cranial neuropathies the most common neurological signs on admission. Mean preoperative performance status (Karnofsky scale) was 80.2 (range 40-100). Surgical approaches to these tumors included partial labyrinthectomy petrous apicectomy, fronto-temporal/fronto-temporal orbitozygomatic osteotomy, retrosigmoidal, extreme lateral, transpetrosal, and combined. In 38 cases a staged procedure was performed. Gross-total resection was achieved in 57% of patients, and subtotal/partial in 43%. Surgical mortality was 2.5% and complications were encountered in 41% of patients. Postoperative CSF leak occurred in 22 cases (13.6%). The mean follow-up was 19 months, ranging from 0.2 to 63.6, and the mean performance status of patients with a follow-up of at least 12 months was 77 (range of 40-100). Recurrence or progression of disease was found in 13.7% of cases (follow-up 2 years or more).

CONCLUSION

Our experience suggests that although posterior fossa meningiomas represent a continuing challenge for contemporary neurosurgeons, such tumors may be completely or subtotally removed with low rate of mortality and acceptable morbidity, allowing most of these patients to achieve a good outcome in a long-term follow-up.

Chordomas and chondrosarcomas of the skull base: results and complications of surgical management

Object

Chordomas and chondrosarcomas are rare and difficult to treat tumors for which the optimum treatment modality remains controversial. The aim of this study was to evaluate the surgery-related results and complications in a series of patients in whom radical resection was the treatment of choice.

Methods

The authors conducted a retrospective analysis of the surgery-related results and complications associated with chordoma and chondrosarcoma in 64 patients of whom 33 (52%) had previously undergone some form of treatment. Total or near-total excision was achieved in 56% and this rate increased to 68% in patients without prior treatment. The main complications were postoperative cerebrospinal fluid leakage, intraoperative arterial injury, and new-onset cranial nerve deficits. Arterial injury occurred only and perioperative death occurred more often in patients who had undergone previous treatment.

Conclusions

Analysis of the results provides support for a policy of radical excision of chordomas and chondrosarcomas at the time of first presentation. A higher incidence of procedure-related complications is found in patients who have already undergone surgery and radiotherapy.