Intracranial aneurysms

MICHAEL S. KAVIC, MD General Surgery St. Elizabeth Health Center Northeastern Ohio Universities College of Medicine Youngstown, Ohio PII S0149-7944(00)00203-8

REFERENCES 1. Fruchaud HR. Anatomie chirurgicale des hernies de l’aine. Paris: G. Doin, 1956. 2. Bassini E. Nuovo metodo per la cura radicale dell’ernia inguinale. Padua: Stabili-

mento Prosperini, 1889. 3. Lichtenstein IL. Hernia repair without disability (2nd ed). St. Louis: Ishiyaku

EuroAmerica, 1986. 4. Usher FC, Ochsner J, Tuttle LL Jr. Use of Marlex mesh in the repair of incisional

hernias. Ann Surg 1958;24:969 –974. 5. Amid PK, Shulman AG, Lichtenstein IL. Selecting synthetic mesh for the repair of

groin hernia. Postgrad Surg 1992;4:150 –155. 6. Amid PK, Shulman AG, Lichtenstein IL. An analytic comparison of laparoscopic

hernia repair with open “tension-free” hernioplasty. Int Surg 1995;80:9 –17. 7. Lamb JP, Vitale T, Kaminski DL. Comparative evaluation of synthetic meshes

used for abdominal wall replacement. Surgery 1983;93:643– 648. 8. Kavic MS. Laparoscopic hernia repair. Amsterdam: Harwood Academic Publish-

ers, 1997. 9. Crawford DL, Hiatt JR, Phillips EH. Laparoscopy identifies unexpected groin

hernias. Am Surg 1998;64:976 –978. 10. Wantz GE. Testicular atrophy as a risk of inguinal hernia. Surg Gynecol Obstet

1982;154:570 –571. 11. Kavic MS. Laparoscopic transabdominal preperitoneal hernia repair. In: Ben-

david R, editor. Abdominal wall hernia: principles and management. New York: Springer-Verlag, in press. 12. Lichtenstein IL, editor. Hernia repair without disability. St. Louis: Ishiyaku Eu-

roamerica, 1986. 13. Baker JW, Evoy MM. Insult to the testicle in herniorrhaphy. Surg Gynecol Obstet

1942;75:285–288. 14. Nilson E, Kald A, Anderberg B, et al. Hernia surgery in a defined population: a

prospective three-year audit. Eur J Surg 1997;163:823– 829. 15. Kavic MS. Chronic pelvic pain, hernias, and the general surgeon. In: Bendavid R,

editor. Abdominal wall hernia: principles and management. New York: SpringerVerlag, in press.

Neurology Intracranial Aneurysms Guest Reviewers: Vijay K. Mittal, MD, Fahim A. Habib, MD, Teck Soo, MD, and Shun C. Young, MD CURRENT SURGERY • Volume 57/Number 3 • May/June 2000

197

REVIEWER COMMENTS

This study has the merit of having a large patient population from multiple centers, and being executed meticulously, as is shown in the pilot interobserver reliability testing for radiological interpretation, central adjudication of endpoints, the use of a standardized follow-up questionnaire, the use of validated instruments (Rankin scale and the Mini-Mental State) for measurement of neurologic outcome, and multivariable analysis for the adjustment of confounders. However, the limitation of the study lies in its design. To compare the rupture rate from a retrospective chart review with surgeryrelated mortality and morbidity from prospective data was suboptimal, given the nature of retrospective data and its period of collection. It would also be helpful if the authors could state clearly the criteria for enrollment with or without treatment in the prospective component. The logical next step will be to examine prospectively the rupture and mortality/morbidity rates between treatment and nontreatment groups or between surgical and nonsurgical (eg, endovascular coiling) groups among unruptured aneurysms.

UNRUPTURED INTRACRANIAL ANEURYSMS—RISK OF RUPTURE AND RISKS OF SURGICAL INTERVENTION. INTERNATIONAL STUDY OF UNRUPTURED INTRACRANIAL ANEURYSMS INVESTIGATORS. N Engl J Med 1998;339:1725–1733. Objective: The objectives of this study were twofold: to determine the natural his-

tory of unruptured intracranial aneurysms and to evaluate the morbidity and mortality associated with the treatment of unruptured intracranial aneurysms. Design: Combined retrospective and prospective study. Setting: Multicenter study with 53 participating centers in the United States, Can-

ada, and Europe. Participants: Data on the retrospective cohort were obtained by examining medical

records, at participating centers, during the period from 1970 to 1991. This cohort included patients with at least 1 unruptured intracranial aneurysm, with or without associated symptoms. The prospective component of the study included patients with diagnosed intracranial aneurysms between 1991 and 1995 with or without planned surgical or endovascular treatment of one such aneurysm. Results: Of 1449 patients in the retrospective component of the study, 727 had no

history of a subarachanoid hemorrhage (group 1), and 722 patients had a history of subarachanoid hemorrhage from a different aneurysm that had been repaired successfully (group 2). Thirty-two of the 1449 patients (2.2%) had confirmed rupture of the aneurysm during the follow-up period, with 28 of these occurring within the first 7.5 years. The cumulative rate of rupture for aneurysms less than 10 mm in diameter was 0.05% per year for patients in group 1, and 0.5% for those in group 2. For aneurysms greater than 10 mm in diameter, the risk of rupture was similar for both groups, approaching 1%. Additionally, the location of the aneurysm was found to have independent prognostic significance. Aneurysms located in the basilar tip, vertebrobasilar, and aneurysms of the posterior cerebral circulation were at greater risk for rupture. Of 1172 patients in the prospective cohort, surgery-related morbidity and mortality, at 30 days, occurred in 17.5% of patients in group 1, and 13.6% of patients in group 2. Corresponding rates at 1-year after surgery were 15.7% and 13.1%, respectively. Age was the only independent predictor of a poor surgical outcome. Conclusions: The risk of rupture of an intracerebral aneurysm of less than 10 mm diameter without a history of previous subarachanoid hemorrhage is exceedingly low. The surgery-related risk of mortality and morbidity greatly exceeds the risk of rupture in this group of patients.

REVIEWER COMMENTS

The limitations of this study include the lack of data on aneurysm neck size and geometry, the degrees of recanalization, and thrombosis. Data were also incomplete to assess the protective nature of “acute” coiling. In addition, a mean 10 to 13 months of follow-up is inadequate to assess the risks of rupture and rebleeding.

ENDOVASCULAR EMBOLIZATION OF 150 BASILAR TIP ANEURYSMS WITH GUGIELMI DETACHABLE COILS: RESULTS OF THE FOOD AND DRUG ADMINISTRATION MULTICENTER CLINICAL TRIAL. Eskridge JM, Song JK, and the Participants. J Neurosurg 1998;89:81– 86. Objective: To evaluate the safety and efficacy of Guglielmi detachable coils in the

treatment of ruptured and unruptured intracranial aneurysms in patients deemed to be at high risk for surgery. Design: Prospective database. Setting: Multicenter study involving 21 institutions in the United States. Participants: From January 1991 to September 1995, 150 patients having harbored

basilar tip aneurysms and whose referring neurosurgeons had excluded the patients as surgical candidates were included in the study. The base of the aneurysm was packed 198

CURRENT SURGERY • Volume 57/Number 3 • May/June 2000

with coils. Percentage occlusion determined using standard cerebral angiography was evaluated as a means of determining technical success. Adverse events and mortality were recorded. Results: After excluding the withdrawals and the deaths in which no coils were

inserted, the mean follow-up time for 61 of 83 patients with ruptured aneurysms was 13.7 months and that for 49 out of 67 patients with unruptured aneurysms was 9.8 months. The mortality rates with conservative treatment were 23% for ruptured and 12% for unruptured aneurysms. With treatment, the rebleeding rates were 3.3 % and 4.1%, respectively. Permanent deficits from stroke occurred in 5% of patients with ruptured aneurysms and in 9% of patients with unruptured aneurysms. Vasospasms occurred in 8% of patients. The periprocedural mortality was 2.7%. Conclusions: Guglielmi detachable coils showed a great reduction in mortality and

morbidity in inoperable patients when compared with conservative medical management. However, its role in the treatment of unruptured basilar tip aneurysms was not supported.

SELECTION OF CEREBRAL ANEURYSMS FOR TREATMENT USING GUGLIEMI DETACHABLE COILS: THE PRELIMINARY UNIVERSITY OF ILLINOIS AT CHICAGO EXPERIENCE. Debrun GM, Aletich VA, Kehrlu P, et al. Neurosurgery 1998;43:1281–1297. Objective: To determine criteria rendering cerebral aneurysms suitable for treatment with Guglielmi detachable coils and to evaluate the impact of aneurysm geometry on outcome. Design: Retrospective analysis. Setting: University of Illinois at Chicago.

REVIEWER COMMENTS

This study supports the use of Guglielmi detachable coils in a certain subgroup of intracranial aneurysms and highlighted the importance of aneurysm geometry in the patient selection. The limitation of the study is the retrospective nature of the data, and thus, its inability to prevent bias or to minimize missing data. A prospective study to address these issues is warranted.

Participants: One hundred forty-four patients underwent treatment of their intra-

cranial aneurysm during the period May 1994 to June 1997. The initial 25 patients (group 1) underwent coiling by virtue of being unsuitable for surgical intervention. In the remainder (group 2), selection for coiling was based on the aneurysm geometry and diameter. Results: For the initial group of 25 patients, when selection was restricted to a

nonsurgical candidate and not on the geometry of the aneurysm, high morbidity and mortality rates occurred, with 56% of the treated aneurysms occluded at 6 months. For the remaining 119 patients, the selection was based on aneurysm geometry, with a dome-to-neck ratio of at least 2 and an absolute neck diameter less than 5 mm. In this group, the mortality and morbidity related to the procedure was low. The occlusion rate was much better with a complete occlusion rate of 72% among the acutely ruptured aneurysms and 80% among the nonacute aneurysms. Conclusions: These data showed that Guglielmi detachable coils is a safe and effi-

cient technique when used in patients selected for aneurysm geometry. The percentage of complete aneurysm occlusion is related to the density of coil packing, which again is dependent on the aneurysm geometry. The optimal results are obtained with a dometo-neck ratio of 2.

RUPTURE INTRACRANIAL ANEURYSMS: ACUTE ENDOVASCULAR TREATMENT WITH ELECTROLYTICALLY DETACHABLE COILS—A PROSPECTIVE RANDOMIZED STUDY. Vanninen R, Koivisto T, Hernesniemi J, Vapalahati M. Radiology 1999;211:325–336.

CURRENT SURGERY • Volume 57/Number 3 • May/June 2000

REVIEWER COMMENTS

This study clearly demonstrates the influence of the patient’s initial clinical status as determined by the Hunt and Hess 199

REVIEWER COMMENTS (Con’t)

grade on outcome. Although endovascular treatment appears to effective in the management of ruptured aneurysms in select patients, its use until now has been mainly restricted to cases in which surgery has been considered inappropriate. This prospective randomized trial begins to address the use of endovascular coils as an alternative to surgery. It is, however, clear that results of surgery are superior in certain anatomic locations and with certain types of aneurysmal anatomy. Further, the study is limited by a lack of longterm follow-up with recanalization rates as yet to be determined. The development of alternative endovascular techniques, including endovascular stents and grafts is also eagerly awaited.

Objective: To compare the use of endovascular electrolytically detachable coils versus surgery in the treatment of acutely ruptured intracranial aneurysms. Design: Prospective randomized study. Setting: Tertiary care university hospital. Participants: Of 242 consecutive patients with angiographically proved aneurysmal

subarachanoid hemorrhage during the period February 1995 to August 1997, 111 were randomly assigned to either undergo surgical clipping or endovascular detachable coil placement. Of these patients, 109 were available for analyses. Similar postprocedure care in the intensive care unit, follow-up angiography, and neuropsychologic examinations were performed in the 2 groups. Results: Results of surgical ligation are significantly better for aneurysms of the

anterior cerebral artery. Endovascular treatment appears to be superior for aneurysms of the posterior cerebral circulation. No difference in outcome is observed between the 2 groups for aneurysms developing from the middle cerebral or the internal carotid artery. Early rebleeding was observed in 1 patient in the endovascular group. The technique-related mortality was 4% in the surgical group and 2% in the endovascular group. The clinical outcome was not different in the 2 groups. An increased need for shunt creation for management of hydrocephalus was noted in the surgical group. No late rebleedings occurred in either group. Conclusions: In selected patients, notably, those with aneurysms of the posterior cerebral circulation, endovascular coil embolization may present as a viable alternative to surgical ligation. The long-term effects of this treatment are, however, at the present time unknown.

REVIEWER SUMMARY Intracranial aneurysms are a clinically significant entity and estimated to cause 27,000 strokes annually, of which about 14,000 are fatal.1 According to most autopsy/radiologic studies, intracranial aneurysms are found in 1% to 6% of the general population. Hence, most aneurysms are asymptomatic. The devastating consequence of rupture with only 30% to 40% of the patients returning to their previous level of functioning despite modern medical interventions has provided the impetus for treating asymptomatic aneurysms.2 Asymptomatic incidental aneurysms are increasingly being detected by the widespread use of neuroimaging modalities, including computed tomography (CT), magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA). Screening of the families of patients with aneurysms is increasingly being pursued.3 The management of these lesions based on their natural history and risk associated with treatment suggests that aneurysms with a size less than 10 mm in a patient without past history of ruptured aneurysm need not be treated with conventional clipping (see the reviewed article by the International Study of Unruptured Intracranial Aneuryisms Investigators). Size and location of lesion, age and general health of patient, presence or absence of family history, and level of patient’s anxiety should be factored into the decision-making process. Symptomatic aneurysms from rupture, mass effect, or thromboembolic phenomenon are treated. Ruptured aneurysms are ideally secured early to prevent rebleeding. Hypervolemic, hypertensive, and hemodilution therapy is instituted and nimodipine begun to prevent and treat vasospasm.4 Vasospasm remains the major cause of mortality and morbidity in patients surviving subarachnoid hemorrhage long enough to receive medical care, even exceeding the direct effects of aneurysmal rupture or rebleeding.5 It mandates management in the intensive care unit, with invasive monitoring, aggressive use of fluids and inotropic agents, cerebral blood flow studies, and frequent clinical checks. 200

CURRENT SURGERY • Volume 57/Number 3 • May/June 2000

Conventional clipping of an aneurysm is currently prospectively being compared with interventional neuroradiologic endovascular techniques using the thrombosing Guglielmi detachable coils6 or balloon embolization. Stents are also under evaluation at this time. These minimally invasive techniques are already being employed as the modality of choice in the treatment of intracerebral aneurysms in the difficult patient as well as aneurysms in difficult locations, and they may, in the not-too-distant future, become the dominant modality in the treatment of intracerebral aneurysms.

VIJAY K. MITTAL, MD FAHIM A. HABIB, MD TECK SOO, MD SHUN C. YOUNG, MD Providence Hospital & Medical Center Southfield, Michigan PII S0149-7944(00)00206-3

REFERENCES 1. Ignall TJ, Whisnant JP, Wiebers DO, O’Fallon WM. Has there been a decline of

subarachanoid hemorrhage mortality? Stroke 1989;20:718 –724. 2. Sacco RL, Wolf PA, Bharucha NE, et al. Subarachnoid and intracerebral hemor-

rhage: natural history, prognosis, and precursive factors in the Framingham Study. Neurology 1984;34:847– 854. 3. Lozano AM, Leblanc R J. Familial intracranial aneurysms. Neurosurgery 1987;66:

522–528. 4. Kassell NF, Baumann KW, Hitchon PW, et al. Influence of a continuous high

dose infusion of mannitol on cerebral blood flow in normal dogs. Neurosurgery 1981;9:283–286. 5. Weir B, MacDonald L. Cerebral vasospasm. Clin Neurosurg 1993;40:40 –55. 6. Guglielmi G, Vinuela F, Duckwiler G, et al. Endovascular treatment of posterior

circulation aneurysms by electrothrombosis using electrically detachable coils. J Neurosurg 1992;77:515–524.

Neurology Sound Mind in a Sound Body Guest Reviewer: James H. North, Jr, LTC, USA, MC RELATIONSHIP BETWEEN CEREBRAL BLOOD FLOW AND THE DEVELOPMENT OF SWELLING AND LIFE-THREATENING HERNIATION IN ACUTE ISCHEMIC STROKE. Firlik AD, Yonas H, Kaufmann AM, et al. J Neurosurg 1998; 89:243–249. Objective: To determine whether cerebral blood flow in acute stroke could be cor-

related with the development of cerebral edema and brain herniation. Design: Retrospective review. Setting: Departments of Neurological Surgery, Neurology, and Radiology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania. Participants: Twenty patients with a diagnosis of acute middle cerebral artery ter-

CURRENT SURGERY • Volume 57/Number 3 • May/June 2000

REVIEWER COMMENTS

Life-threatening, complete middle cerebral artery infarction can lead to postischemic brain edema, increased intracranial pressure, herniation, and death. This is termed the “malignant” middle cerebral artery infarction. No reliable clinical indicators of herniation exist after stroke. This retrospective study demonstrated the utility of cerebral blood flow measurements using xenon-enhanced CT in patients with acute stroke. Regions with lower cerebral blood flow are at risk for 201