Petrous carotid-to-intradural carotid saphenous vein graft for intracavernous giant aneurysm, tumor, and occlusive cerebrovascular disease

Thrombotic Intracranial Aneurysms: Classification Scheme and Management Strategies in 68 Patients

OBJECTIVE:

Thrombotic aneurysms are a diverse collection of complex aneurysms characterized by organized intraluminal thrombus and solid mass. Consequently, their treatment often requires techniques other than conventional clipping, such as thrombectomy with clip reconstruction or bypass with parent artery occlusion. A single-surgeon experience with thrombotic aneurysms was analyzed to determine optimal treatment strategies. A classification scheme was devised on the basis of aneurysm, thrombus, and lumen morphology to relate these anatomic features to surgical therapy.

METHODS:

Sixty-eight patients with thrombotic aneurysms were managed during a period of 6.25 years. Thrombotic aneurysms were classified into six types: concentric (n = 17, 25%), eccentric (n = 14, 21%), lobulated (n = 2, 3%), complete (n = 2, 3%), canalized (n = 17, 25%), and coiled (n = 16, 24%).

RESULTS:

Aneurysm management consisted of direct clipping (n = 22, 32%), thrombectomy-clip reconstruction (n = 18, 26%), bypass-occlusion (n = 20, 29%), other (n = 6, 9%), or observation (n = 2, 3%). Complete angiographic obliteration was achieved in 97% of patients, and 47% of aneurysms were thrombectomized. The surgical mortality rate was 6%, and the permanent neurological morbidity rate was 7%. Overall, 87% of patients were improved or unchanged at follow-up, with 79% reaching a Glasgow Outcome Scale score of 5 or 4. Management strategy was influenced by thrombotic aneurysm type, but patient outcome was not. The best results were observed in patients treated with direct clipping and bypass-occlusion.

CONCLUSION:

Despite their solid mass, one-third of thrombotic aneurysms can be treated surgically with conventional clipping. Direct clipping is associated with the best surgical results, and the proposed classification scheme identifies thrombotic aneurysms that may be clippable. Patients with unclippable thrombotic aneurysms had more favorable results when treated with bypass and aneurysm occlusion than with thrombectomy and clip reconstruction. The classification scheme may provide conceptual clarity and therapeutic guidance with preoperative and intraoperative decision making.

Combined surgical and endovascular treatment of a recurrent A3–A3 junction aneurysm unsuitable for standalone clip ligation or coil occlusion

Recurrent aneurysms of the anterior circulation that are distal to the anterior communicating artery (ACoA) but proximal to the callosomarginal–pericallosal bifurcation can pose a treatment challenge. The authors present one such case, in which the patient was treated with pericallosal artery–pericallosal artery (PerA–PerA) side-to-side bypass, followed by endovascular obliteration of the proximal A2 parent vessel. This patient, in whom an ACoA aneurysm had been treated with clip ligation 5 years previously, presented with a new, mid-A2, right-sided aneurysm with the out-flow artery arising from the dome of the lesion.

The treatment plan included two steps: an interhemispheric transcallosal approach for PerA–PerA side-to-side anastomosis; and endovascular coil embolization of the right A2 branch feeding the aneurysm. Postprocedure angiography demonstrated no ipsilateral aneurysm filling and excellent bilateral distal outflow from the anterior cerebral artery (ACA).

The use of PerA–PerA side-to-side bypass for the treatment of an ACA aneurysm, followed by parent vessel occlusion, offers an elegant solution for the treatment of A2 aneurysms that are not amenable to stand-alone clip ligation or coil occlusion. Such combined methods are invaluable in the management of complex cerebral aneurysms.

Use of “Bonnet” Bypass with Radial Artery Interposition Graft in a Patient with Recurrent Cranial Base Carcinoma: Technical Report of Two Cases and Review of the Literature

OBJECTIVE AND IMPORTANCE:

Two patients with recurrent cranial base carcinomas involving the carotid artery received a “bonnet” bypass using the contralateral superficial temporal artery as the donor vessel because the ipsilateral common and external carotid arteries were unavailable. The radial artery was used as the graft.

CLINICAL PRESENTATION:

A 58-year-old man with ear pain and an enlarging mass involving the left cranial base and neck had undergone a right partial glossectomy and modified neck dissection followed by radiotherapy for squamous cell carcinoma. Recurrent carcinoma extensively involved the left internal carotid artery. A 46-year-old man with jaw pain and hoarseness had undergone multiple resections and radiation therapy for medullary thyroid carcinoma. Magnetic resonance imaging showed recurrent tumor on the right.

INTERVENTION:

Both patients underwent a pterional craniotomy. The supraclinoid internal carotid artery was exposed. The radial artery was harvested. The contralateral superficial temporal artery was dissected at its bifurcation into the frontal and parietal branches. The radial artery graft was anastomosed to the superficial temporal artery and a recipient ipsilateral branch of the middle cerebral artery. The internal carotid artery was clip-ligated. After surgery, both patients remained neurologically stable. Angiography confirmed that the bypasses were patent and that the middle cerebral artery territory filled. The patients’ carcinomas were resected aggressively.

CONCLUSION:

When aggressive resection of cranial base tumors is needed and the ipsilateral carotid artery is unavailable as a donor vessel, a “bonnet” bypass with carotid artery sacrifice may be performed. Compared with vein grafts, microsurgical anastomosis is easier and the patency rate is higher with a radial artery graft.

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.

Microsurgical anatomy of cerebral revascularization. Part I: Anterior circulation

Object. Revascularization is an important component of treatment for complex aneurysms that require parent vessel occlusion, skull base tumors that involve major vessels, and certain ischemic diseases. In this study, the authors examined the microsurgical anatomy of cerebral revascularization in the anterior circulation by demonstrating various procedures for bypass surgery.

Methods. Twenty-five adult cadaveric specimens were studied, using 3 to 40 magnification, after the arteries and veins had been perfused with colored silicone. The microsurgical anatomy of cerebral revascularization in the anterior circulation was examined with the focus on the donor, recipient, and graft vessels. The techniques discussed in this paper include the superficial temporal artery (STA)—middle cerebral artery (MCA), middle meningeal artery (MMA)—MCA, and side-to-side anastomoses; short arterial and venous interposition grafting; and external carotid artery/internal carotid artery (ICA)—M2 and ICA—ICA bypasses. Bypass procedures for cerebral revascularization are divided into two categories depending on their flow volume: low-flow and high-flow bypasses. A low-flow bypass, such as the STA—MCA anastomosis, is used to cover a relatively small area, whereas a high-flow bypass, such as the ICA—ICA anastomosis, is used for larger areas. Cerebral revascularization techniques are also divided into two types depending on the graft materials: pedicled arterial grafts, such as STA and occipital artery grafts, and free venous or arterial grafts, which are usually saphenous vein and radial artery grafts. Pedicled arterial grafts are mainly used for low-flow bypasses, whereas venous or arterial grafts are used for high-flow bypasses.

Conclusions. It is important to understand the methods of bypass procedures and to consider indications in which cerebral revascularization is needed.

Saphenous vein graft for bypass of the external carotid artery to supraclinoid internal carotid artery using a modified technique: an anatomical and technical study

OBJECTIVE

To investigate the use of a saphenous vein graft for bypass of the external carotid artery (ECA) to supraclinoid internal carotid artery (ICA) when the proximal middle cerebral artery (MCA) is not suitable for a bypass procedure.

MATERIAL AND METHODS

Five adult cadaver sides were used. Dissection required a frontotemporal craniotomy and a zygomatic arch osteotomy, with a hole being opened 2-3 mm lateral to the foramen rotundum extradurally. The ECA was found easily via a second incision in the cervical region. The ophthalmic segment of the ICA was exposed by removal of the anterior clinoid process intradurally. After the dura over the hole was opened, the 7-8-cm long bypass graft was passed just behind the mandibula and through the hole inside the dura to reach the ICA. The ECA was then transected proximal to the occipital artery (OA) branch and the distal side of the vein graft was anastomosed end-to-end with the ECA and end-to-side with the supraclinoid ICA.

RESULTS

The mean diameter of the ECA proximal to the OA was 3.75+/-0.4 mm (range 3.35-4.15 mm) and that of the supraclinoid ICA was 3.4+/-0.5 mm (range 2.9-3.9 mm). The mean length of the venous graft was 7.5+/-0.5 cm (range 7-8 cm).

CONCLUSION

When high blood flow is needed and the proximal MCA is not suitable for a bypass, the bypass described herein may be an alternative to a superficial temporal to MCA bypass as well as to extracranial carotid artery to MCA or ICA bypasses, which both need long vein grafts.

Complex tumors of the glomus jugulare: criteria, treatment, and outcome

Object

Tumors of the glomus jugulare are benign, slow-growing paragangliomas. Their natural history, surgical treatment, and outcome have been well addressed in the recent literature; however, there remains a subgroup of complex tumors—multiple, giant, malignant, neuropeptide-secreting lesions, and those treated previously by an intervention with an adverse outcome—that is high risk, presents surgical challenges, and is associated with treatment controversy. In this article the authors report on a series of patients with complex glomus jugulare tumors and focus on treatment decisions, avoidance of complications, surgical refinements, and patient outcomes.

Methods

In this retrospective study, the patient population was composed of 11 male and 32 female patients (mean age 47 years) with complex tumors of the glomus jugulare who were treated by the senior author within the past 20 years. These include 38 patients with giant tumors, 11 with multiple paragangliomas (seven bilateral and four ipsilateral), two with tumors that hypersecreted catecholamine, and one with a malignant tumor. Six patients had associated lesions: one dural arteriovenous malformation, one carotid artery (CA) aneurysm, two adrenal tumors, and two other cranial tumors.

All but one patient presented with neurological deficits. Cranial nerve deficits, particularly those associated with the lower cranial nerves, were the prominent feature. Twenty-eight patients underwent resection in an attempt at total removal, and gross-total resection was achieved in 24 patients. Particularly challenging were cases in which the patient had undergone prior embolization or CA occlusion, after which new feeding vessels from the internal CA and vertebrobasilar artery circulation developed.

The surgical technique was tailored to each patient and each tumor. It was modified to preserve facial nerve function, particularly in patients with bilateral tumors. Intrabulbar dissection was performed to increase the likelihood that the lower cranial nerves would be preserved. Each tumor was isolated to improve its resectability and prevent blood loss. No operative mortality occurred. In one patient hemiplegia developed postoperatively due to CA thrombosis, but the patient recovered after an endovascular injection of urokinase. In four patients a cerebrospinal fluid leak was treated through spinal drainage, and in five patients infection developed in the external ear canal. Two of these infections progressed to osteomyelitis of the temporal bone. There were two recurrences, one in a patient with a malignant tumor who eventually died of the disease.

Conclusions

Despite the challenges encountered in treating complex glomus jugulare tumors, resection is indicated and successful. Multiple tumors mandate a treatment plan that addresses the risk of bilateral cranial nerve deficits. The intra-bulbar dissection technique can be used with any tumor, as long as the tumor itself has not penetrated the wall of the jugular bulb or infiltrated the cranial nerves. Tumors that hypersecrete catecholamine require perioperative management and malignant tumors carry a poor prognosis.

Radial Artery Graft for Bypass of the Maxillary to Proximal Middle Cerebral Artery: An Anatomic and Technical Study

OBJECTIVE

In this study, we aimed to investigate the use of a radial artery graft for bypass of the maxillary artery (MA) to the proximal middle cerebral artery (MCA) as an alternative to superficial temporal artery-to-MCA anastomosis or extracranial carotid-to-MCA bypass using long grafts.

METHODS

Five adult cadavers were used bilaterally. After a frontotemporal craniotomy and a zygomatic arch osteotomy, the MA was found easily 1 to 2 cm inferior to the infratemporal crest. A hole was created with a 4-mm-tip drill in the sphenoid bone 2 to 3 mm lateral to the foramen rotundum extradurally, and the dura over the hole was opened. After the carotid and sylvian cisterns had been opened, the M2 segment of the MCA was exposed. The graft was passed through the hole to reach the M2 segment. Then, the MA was freed from the surrounding tissue and was transected before the infraorbital artery branch. The radial artery graft was anastomosed end-to-end to the MA proximally and end-to-side to the M2 segment of the MCA distally.

RESULTS

The mean thickness of the MA before the infraorbital artery branch was 2.6 ± 0.3 mm. The mean thickness of the largest trunk of the MCA was 2.3 ± 0.3 mm. The average length of the graft was 36 ± 5.5 mm.

CONCLUSION

MA-to-MCA bypass is as feasible as proximal MCA revascularization using long vein grafts. The thickness of the MA provides sufficient flow; the length of the graft is short, and it has a straight course. MA-to-proximal MCA bypass may be an alternative to superficial temporal artery-to-MCA as well as extracranial carotid-to-MCA bypasses.

Proximal superficial temporal artery to proximal middle cerebral artery bypass using a radial artery graft: an anatomic approach

We present the use of radial artery graft for bypass of the proximal superficial temporal artery to the proximal middle cerebral artery. Six adult cadaver sites were used bilaterally. After apterional incision, 2x2-cm minicraniectomy was performed which began 2 cm behind the zygomatic process of the frontal bone. The superficial temporal artery was transsected before exposing the zygomatico-orbital artery branch. The proximal side of the radial artery graft was anastomosed end-to-end to the proximal superficial temporal artery and the distal side end-to-side to the proximal middle cerebral artery. The mean calibers of the proximal superficial temporal artery and largest trunk of the middle cerebral artery were 2.25+/-0.35 mm and 2.3+/-0.3 mm, respectively. The average graft length was 85+/-5.5 mm. We conclude that such bypasses are simpler than proximal middle cerebral artery revascularization using long vein grafts. This method proves that the caliber of the proximal superficial temporal artery is more suited to providing sufficient flow than the distal superficial temporal artery, and the graft is short. Such bypasses to the middle cerebral artery may be an alternative to those from the distal superficial temporal artery or extracranial carotid artery.

Microsuture-tying forceps with attached scissors for bypass surgery

BACKGROUND

Bypass surgery requires the shortest temporary occlusion time of a recipient artery during anastomosis. For this purpose, we have devised a microforceps with attached scissors that makes it possible to perform the multiple steps involved in anastomosis without exchanging instruments. This microforceps avoids having to exchange instruments twice in one suturing, such as that between a microsuture-tying forceps or a microneedle holder and microscissors in conventional methods.

METHODS

The instrument is made of stainless steel and is 15.5 cm long. Using this microforceps with scissors, we can suture, tie, and cut a ligature fluently for consecutive sutures without exchanging instruments. The mean time during one suturing was compared between two patient groups treated by conventional method and with use of this instrument.

RESULTS

This instrument was used for 34 patients with ischemic cerebrovascular disease (including three who needed deep-site anastomoses) and allowed us to perform superficial temporal artery-middle cerebral artery (STA-MCA) anastomoses uneventfully. This instrument saved 15.2 s in the mean time during one suturing.

CONCLUSIONS

Although it is of paramount importance to practice tying sutures well, this new instrument removes the need to exchange conventional instruments, and we believe it will save time and, therefore, decrease complications during bypass surgery.

Cerebral revascularization

During the last 10 years, there has been a revival of interest in cerebral revascularization procedures. Not only have significant progressions in surgical techniques been published, the use of more advanced diagnostic methods has led to a widening of the indications for cerebral bypass surgery. The purpose of this review is to outline the current techniques for extracranial-to-intracranial (EC/IC) and intracranial-to-intracranial (IC/IC) bypass surgery, as well as to identify the current indications for revascularization procedures based on the available literature. The excimer laser-assisted non-occlusive anastomosis (ELANA) technique is described in more detail because we think that this technique almost completely eliminates the risk of cerebral ischemia due to the temporary vessel occlusion which is currently used in conventional anastomosis techniques.

Selective cerebral revascularization as an adjunct in the treatment of giant anterior circulation aneurysms

Cerebral revascularization, an indispensable component of neurovascular surgery, has been performed in the treatment of cranial base tumors, complex cerebral aneurysms, and occlusive cerebrovascular disease. The goal of a revascularization procedure is to augment blood flow distally. It can therefore be used as an adjunctive measure in the treatment of complex neurosurgical disease processes that require parent artery sacrifice for definitive treatment. In the treatment of giant anterior circulation aneurysms, for instance, a cerebral revascularization procedure may be considered in patients in whom the collateral circulation is marginal and in whom lesions may be treated either using a Hunterian-based strategy or clip-assisted reconstruction requiring a prolonged period of temporary occlusion. To date, there is no entirely effective method known to produce long-term tolerance to carotid artery (CA) sacrifice and, largely for that reason, some neurovascular surgeons advocate universal revascularization. The authors of this report, however, prefer to perform revascularization only in the limited subset of patients in whom preoperative assessment has revealed risk factors for cerebral ischemia due to hypoperfusion. In this paper, the authors introduce their protocol for assessing cerebrovascular reserve capacity, indications for cerebral revascularization in the treatment of complex anterior circulation aneurysms, and discuss their rationale for choosing to practice selective, rather than universal, revascularization.

Conduits for cerebrovascular bypass and lessons learned from the cardiovascular experience

Direct cerebral revascularization is an important procedure in the treatment of certain complex aneurysms and skull base tumors when acute sacrifice of the internal carotid artery is required. It likely remains an appropriate treatment in a small subgroup of patients with cerebral ischemia refractory to maximal medical management. Similar to cardiovascular surgery, the choice of a graft conduit is critical for a successful outcome. The standard conduits are interposition vein grafts (usually the greater saphenous vein), free arterial grafts (radial artery), and pedicled arterial grafts (superficial temporal artery). The goal of this review is to summarize the conduits commonly used in cerebral revascularization with emphasis on their patency rates and flow characteristics. Comparisons are made with similar data available in the cardiovascular literature.

Interpositional carotid artery bypass strategies in the surgical management of aneurysms and tumors of the skull base

Cerebral revascularization is an important component in the surgical management of complex skull base tumors and aneurysms. Patients who harbor complex aneurysms that cannot be clipped directly and in whom parent vessel occlusion cannot be tolerated may require cerebrovascular bypass surgery. In cases in which skull base tumors encase the carotid artery (CA) and a resection is desired, a cerebrovascular bypass may be necessary in planned CA occlusion or sacrifice. In this review the authors discuss options for performing high-flow anterograde interposition CA bypass for lesions of the skull base. The authors review three important bypass techniques involving saphenous vein grafts: the cervical-to-petrous internal carotid artery (ICA), petrous-to-supraclinoid ICA, and cervical-to-supraclinoid ICA bypass. These revascularization techniques are important tools in the surgical treatment of complex aneurysms and tumors of the skull base and cavernous sinus.

Combined microsurgical and endovascular management of complex intracranial aneurysms

OBJECTIVE

The disciplines of microneurosurgery and cranial base surgery have reached maturity, and technical advances in the surgical management of aneurysms are limited. Although most aneurysms can be clipped microsurgically or coiled endovascularly, a subset of patients may require a combined approach. A consecutive series of patients with aneurysms in one surgeon's cerebrovascular practice was reviewed retrospectively to analyze strategies for integrating microsurgical and endovascular techniques in the management of complex aneurysms.

METHODS

Between 1997 and 2001, 596 aneurysms in 491 patients were treated microsurgically by the senior author (MTL) at the University of California, San Francisco, and 77 of these patients (96 aneurysms) were managed with a multimodality approach comprising a total of eight different combinations: selective revascularization and aneurysm occlusion (n = 23), endovascular and surgical trapping (n = 1), clipping of the aneurysm after attempted or incomplete coiling (n = 22), coiling after attempted or incomplete clipping (n = 5), clipping of recurrent aneurysm after coiling (n = 6), coiling of recurrent aneurysm after clipping (n = 1), clipping and coiling of multiple remote aneurysms (n = 13), and coiling after previous surgery (n = 6).

RESULTS

A total of 96 aneurysms were treated with combined therapy, of which 43% were large or giant in size and 34% had fusiform or dolichoectatic morphology. Complete angiographic obliteration was achieved in 91 aneurysms (95%). Overall, 66 patients (86%) had good outcomes (Glasgow Outcome Scale score of 4 or 5; mean follow-up, 9 mo). The treatment mortality rate was 9.1% (seven patients), and permanent treatment-associated neurological morbidity rate was 5.2% (four patients).

CONCLUSION

Evolving endovascular technologies need to be integrated into the microsurgical management of aneurysms. Multimodality approaches are best used with complex aneurysms in which conventional therapy with a single modality has failed. Revascularization remains a unique surgical contribution to the overall management of aneurysms with which current endovascular techniques cannot be used. Multimodality management should be considered an elegant addition to the therapeutic armamentarium that, through simplification and increased safety, improves the treatment of complex aneurysms beyond what is achievable by performing clipping or coiling alone.

Complex tumors of the glomus jugulare: criteria, treatment, and outcome

OBJECT

Tumors of the glomus jugulare are benign, slow-growing paragangliomas. Their natural history, surgical treatment, and outcome have been well addressed in the recent literature; however, there remains a subgroup of complex tumors--multiple, giant, malignant, neuropeptide-secreting lesions, and those treated previously by an intervention with an adverse outcome--that is high risk, presents surgical challenges, and is associated with treatment controversy. In this article the authors report on a series of patients with complex glomus jugulare tumors and focus on treatment decisions, avoidance of complications, surgical refinements, and patient outcomes.

METHODS

In this retrospective study, the patient population was composed of 11 male and 32 female patients (mean age 47 years) with complex tumors of the glomus jugulare who were treated by the senior author within the past 20 years. These include 38 patients with giant tumors, 11 with multiple paragangliomas (seven bilateral and four ipsilateral), two with tumors that hypersecreted catecholamine, and one with a malignant tumor. Six patients had associated lesions: one dural arteriovenous malformation, one carotid artery (CA) aneurysm, two adrenal tumors, and two other cranial tumors. All but one patient presented with neurological deficits. Cranial nerve deficits, particularly those associated with the lower cranial nerves, were the prominent feature. Twenty-eight patients underwent resection in an attempt at total removal, and gross-total resection was achieved in 24 patients. Particularly challenging were cases in which the patient had undergone prior embolization or CA occlusion, after which new feeding vessels from the internal CA and vertebrobasilar artery circulation developed. The surgical technique was tailored to each patient and each tumor. It was modified to preserve facial nerve function, particularly in patients with bilateral tumors. Intrabulbar dissection was performed to increase the likelihood that the lower cranial nerves would be preserved. Each tumor was isolated to improve its resectability and prevent blood loss. No operative mortality occurred. In one patient hemiplegia developed postoperatively due to CA thrombosis, but the patient recovered after an endovascular injection of urokinase. In four patients a cerebrospinal fluid leak was treated through spinal drainage, and in five patients infection developed in the external ear canal. Two of these infections progressed to osteomyelitis of the temporal bone. There were two recurrences, one in a patient with a malignant tumor who eventually died of the disease.

CONCLUSIONS

Despite the challenges encountered in treating complex glomus jugulare tumors, resection is indicated and successful. Multiple tumors mandate a treatment plan that addresses the risk of bilateral cranial nerve deficits. The intrabulbar dissection technique can be used with any tumor, as long as the tumor itself has not penetrated the wall of the jugular bulb or infiltrated the cranial nerves. Tumors that hypersecrete catecholamine require perioperative management and malignant tumors carry a poor prognosis.

Extracranial-intracranial vein graft bypass for giant intracranial aneurysm surgery for pediatric patients: two technical case reports

OBJECTIVE AND IMPORTANCE

Herein we describe two cases of extracranial-intracranial vein graft bypasses for the treatment of giant intracranial aneurysms in prepubertal pediatric patients. One patient is, we think, the youngest patient reported in the literature to have been successfully treated in such a manner, with a good long-term outcome. Such grafts seem to enlarge longitudinally during the growth spurt, making such techniques reasonable long-term therapeutic options for the management of complex intracranial aneurysms in pediatric patients.

CLINICAL PRESENTATION

Patient 1, a 13-year-old boy, presented with headaches and rapidly progressive right cavernous sinus syndrome. Computed tomography and cerebral angiography revealed a giant, fusiform, right intracavernous internal carotid artery aneurysm. Patient 2, a 23-month-old girl, was discovered to harbor an asymptomatic, recurrent, giant, fusiform, left M1 middle cerebral artery aneurysm 1 year after presenting with seizures related to subarachnoid hemorrhage from the aneurysm, for which she had been treated with clipping and an M2-M2 anastomosis.

INTERVENTION

Both patients underwent craniotomies, with sacrifice of the proximal parent vessel (the distal cervical internal carotid artery and the proximal middle cerebral artery, respectively), combined with cerebral revascularization through extracranial-intracranial saphenous vein bypass grafts. Both patients experienced excellent long-term clinical outcomes, have undergone significant growth, and exhibit excellent long-term graft patency and aneurysm obliteration.

CONCLUSION

These two cases highlight the safety and efficacy of extracranial-intracranial vein graft bypasses among prepubertal pediatric patients. The indications for bypass procedures to treat giant intracranial aneurysms are discussed, and the technical aspects of maximizing vein bypass graft patency are reviewed.

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.

Saphenous vein graft for bypass of the maxillary to supraclinoid internal carotid artery: an anatomical short study

The use of a saphenous vein graft for bypass of the maxillary artery (MA) to the supraclinoid internal carotid artery (ICA) in internal carotid occlusions is investigated. Five adult cadaver sides were used. Dissection required zygomatic arch osteotomy and a pterional craniotomy with extensive removal of the floor of the middle cranial fossa. The MA was found easily medial to infratemporal crest. The clinoidal segment of the ICA was exposed with the removal of the anterior clinoid process intradurally. The bypass graft was 4 to 5 cm long and was sutured end-to-end to the MA and end-to-side to the supraclinoid ICA. When high blood flow is needed in cases with ICA occlusion, such a bypass may be an alternative to superficial temporal (STA)-to-middle cerebral artery (MCA) bypass as well as to common carotid-to-MCA or-ICA bypass, which needs a long vein graft. This type of bypass will provide the opportunity to clip the ICA proximal to the origin of ophthalmic artery, which may inhibit distal embolization.

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.

Giant petrous carotid aneurysm treated by submandibular carotid—saphenous vein bypass

✓ Petrous and cavernous sinus carotid artery (CA) aneurysms that are not amenable to clip ligation or endovascular therapy may be successfully treated by a saphenous vein bypass, thereby preserving the patency of the CA. The authors report the unique case of a 47-year-old man with a giant fusiform aneurysm of the petrous CA, who presented with a rapid onset of a lateral rectus palsy and diplopia. The lesion was treated by trapping the aneurysm and performing a saphenous vein bypass from the cervical to the intracranial CA. The saphenous vein graft was routed beneath the condyle of the mandible to reduce the overall length of the graft, thereby increasing the likelihood of long-term patency and offering protection to the graft by the mandible, temporal muscle zygomatic process, and masseter and temporal muscles. The presentation and technical aspects of the bypass graft in this unique case are discussed.

Surgical repair of clinoidal segment carotid artery aneurysms unsuitable for endovascular treatment

OBJECTIVE

Clinoidal segment carotid artery aneurysms are surgically challenging lesions. The aneurysm neck originates proximal to the distal dural ring, and the aneurysms typically are larger. Therefore, endovascular techniques are often considered to be the primary treatment option. Treatment techniques and results for 40 clinoidal segment carotid artery aneurysms that were considered unsuitable for contemporary endovascular intervention are analyzed in this report.

METHODS

Forty aneurysms in 33 female and 3 male patients were treated surgically. Fifteen patients had bilateral aneurysms; of these patients, four underwent bilateral craniotomies. Twenty-seven aneurysms were 10 to 14 mm in size, eight were 15 to 24 mm, and five were more than 25 mm. The most common presentation was visual loss, which occurred in 13 patients. Seven patients presented with subarachnoid hemorrhage.

RESULTS

Thirty-seven aneurysms were directly repaired with clipping, two were trapped with bypass, and one was trapped without bypass. The complication rate was 10%, with one major stroke, two minor strokes, and one successfully treated brain abscess.

CONCLUSION

Surgical treatment of clinoidal segment carotid artery aneurysms can produce acceptable outcomes. Specific preoperative and intraoperative techniques facilitate improved surgical results for aneurysms that are not treatable with contemporary endovascular techniques.

Augmentation of endothelial function by endothelin antagonism in human saphenous vein conduits

OBJECT

Cerebral revascularization with saphenous vein (SV) conduits is used in the management of hard-to-treat lesions that require deliberate arterial occlusion and in selected patients with occlusive vascular disease. Endothelial dysfunction is thought to contribute to acute perioperative vasospasm and chronic graft atherosclerosis. In the present study the authors examined the contribution of the potent vasoconstrictor endothelin-1 (ET-1) to endothelial dysfunction in human SVs.

METHODS

The effects of an ET(A/B) receptor antagonist (bosentan), an ET(A) receptor antagonist (BQ-123), and an ET(B) receptor antagonist (BQ-788) on in vitro endothelium-dependent and -independent responses were studied in human SVs. Vascular segments were obtained in 34 patients who had undergone revascularization procedures, and isometric dose-response curves (DRCs) were constructed using the isolated tissue bath procedure as follows: 1) cumulative DRCs to norepinephrine; and 2) DRCs to acetylcholine (ACh) and sodium nitroprusside in the absence and presence of bosentan, BQ-123, or BQ-788. Maximal vasodilatory responses and sensitivity were compared between groups. In the presence of bosentan (Experiment 1) and BQ-123 or BQ-788 (Experiment 2), ACh responses were significantly augmented (percent maximum relaxation values: 7+/-2 [control] compared with 17+/-3 [bosentan], p < 0.002 [Experiment 1]; and 12+/-2 [control] compared with 29+/-2 [BQ-123] and 25+/-2 [BQ-788], p < 0.003 and p < 0.002, respectively [Experiment 2]). The sensitivity of SVs to ACh was unaffected by treatment. These beneficial effects were specific for the endothelium.

CONCLUSIONS

Blockade of ET receptors significantly improves endothelial function in SVs. Furthermore, these effects appear to be independently and maximally mediated by antagonism of either ET(A) or ET(B) receptors. Interventions aimed at improving endothelial function may serve to counter perioperative vasospasm and impede atherosclerosis in SVs used for revascularization procedures.

Effect of external stenting and systemic hypertension on intimal hyperplasia in rat vein grafts

OBJECTIVE

Overdistention of vein grafts in arterial circulation and systemic hypertension are thought to be influential risk factors contributing to vein graft failures. This study tested the effects of external stenting in preventing systemic hypertension and overdistention of the rat vein graft in the long term.

METHODS

Jugular vein grafts were interposed into the carotid artery of normotensive (n = 39) and two-kidney, one-clip hypertensive (n = 30) rats. Jugular vein grafts wrapped with 1.5-mm-diameter polyester stents were used in normotensive (n = 26) and hypertensive (n = 25) rats. The vein grafts were harvested at 1, 2, 4, 8, 12, and 24 weeks after the grafting procedure. The neointimal area and wall thickness were measured by computerized planimetry, and Ki-67 immunohistochemistry was used to detect replicative smooth muscle cells in the graft wall.

RESULTS

In each group, intimal hyperplasia was apparent at 1 week and increased gradually to 24 weeks. The number of Ki-67-positive cells was most increased at 2 weeks after the grafting procedure and gradually decreased thereafter. The numbers of Ki-67-positive cells and the extent of intimal hyperplasia were not significantly different between normotensive and hypertensive rats. Both neointima formation and cell proliferation in the graft wall were significantly reduced by external stenting as compared with the results with unstented grafts.

CONCLUSION

Systemic hypertension by itself is not a risk factor for intimal hyperplasia and experimental vein graft failure in the long term. External stenting is effective against intimal hyperplasia, and it is possible to reduce the subsequent atherosclerotic change of the vein graft wall and improve the long-term patency of the vein graft with external stenting.

Saphenous vein graft bypass in the treatment of giant cavernous sinus aneurysms: report of two cases

Two cases of giant intracavernous aneurysms treated by high flow bypass with saphenous vein graft between the external carotid artery (ECA) and branches of the middle cerebral artery (MCA) are presented. Very often these aneurysms are unclippable because they are fusiform or have a large neck. Occlusion of the internal carotid artery (ICA) is the treatment of choice in many cases. This procedure has however a high risk of brain infarction. Revascularization of the brain by extra-intracranial anastomosis between the superficial temporal artery (STA) and branches of the MCA is frequently performed. This procedure provides however a low flow bypass and brain infarction may occur. We report two cases of giant cavernous sinus aneurysms treated by high flow bypass and endovascular balloon occlusion of the ICA. Immediate high flow revascularization of MCA branches was achieved and the patients showed no ischemic events. Follow-up of 8 and 14 months after operation shows patency of the venous graft and no neurological deficits. Angiographic control examination showed complete aneurysm occlusion in both cases.

Venous and arterial bypass grafts for difficult tumors, aneurysms, and occlusive vascular lesions: evolution of surgical treatment and improved graft results

OBJECTIVE: In the treatment of patients with cranial base tumors, unclippable aneurysms, or medically intractable ischemia, it may be necessary to use high-flow bypass grafts. The indications, surgical techniques and complications are discussed. METHODS: During a 10-year period, 99 saphenous vein grafts and 3 radial artery grafts were performed for 101 patients, i.e., 72 with neoplasms, 23 with aneurysms, and 6 with ischemia. Clinical follow-up monitoring of the patients was by direct examination or telephone interview, with a mean follow-up period of 41.2 months (range, 5-147 mo). Radiological follow-up monitoring was by magnetic resonance imaging, magnetic resonance angiography, or three-dimensional computed tomographic angiography, with a mean follow-up period of 32 months (range, 1-120 mo). During the follow-up period, there was one late graft occlusion and one graft stenosis. RESULTS: The use of intraoperative angiography improved the patency rate from 90 to 98% and reduced the incidence of perioperative stroke from 13 to 9.5%. Ninety-two percent of the patients were in excellent or good neurological condition at the time of discharge from the hospital, compared with 95% before surgery. The perioperative mortality rate was 2%. Other complications included three intracranial hematomas, rupture of a vein graft in a patient with Marfan's syndrome, and five tumor resection-related problems. The long-term survival rates for patients who received grafts were excellent for patients with benign tumors, fair to poor for patients with malignant tumors, good for patients with aneurysms, and excellent for patients with ischemia. CONCLUSION: The results of saphenous vein and radial artery grafting have been greatly improved by the use of intraoperative angiography, improvements in surgical techniques, and improved perioperative treatment.

Extradural approach to intracavernous ICA aneurysms

A series of 115 intracavernous internal carotid artery (ICA) aneurysms have been treated by a direct surgical approach during the past 15 years. Sixty-eight aneurysms were small. Of these 11 were traumatic; nine caused by severe head injury and 2 by ICA injury during transsphenoidal surgery. Twenty-six aneurysms were large and 21 were giant. Thirty-eight aneurysms were clipped, 46 were treated by resection followed by ICA wall reconstruction with interrupted sutures, 16 by excision and proximal/distal ICA end-to-end anastomosis and 15 by resection/grafting. Postoperative angiography was performed in 107 cases and the ICA was found to be patent in 100 of these. Three patients died after surgery, two (with traumatic aneurysms) from associated brain injury and 1 from pulmonary embolism. Oculomotor palsy was present in the immediate postoperative period in 104 patients. However, six months after surgery only 7 patients had residual palsy. The direct surgical approach to intracavernous ICA aneurysms has constantly been changed and improved. The approach in its original version [6] was mainly intradural, whereas its contemporary version in most cases is extradural [10, 11]. The latter approach provides complete exposure of the entire parasellar region, good proximal control of the ICA [13], and good access to the cavernous sinus through the individual "corridors" between the cranial nerves [7]. In the author's opinion the direct surgical approach provides better results than endovascular treatment with regard to patency of the ICA [11].

Long-term patency of radial artery graft bypass for reconstruction of the internal carotid artery. Technical note

Reconstruction of the carotid artery by using a radial artery graft is a useful option that can produce reliable long-term patency for the surgical treatment of giant and/or large aneurysms of the cavernous and paraclinoid internal carotid artery (ICA). During the past 10 years, 43 patients with intracavernous and paraclinoid giant aneurysms of the ICA have been treated by reconstruction of the ICA with radial artery grafts after ligation of the cervical ICA. The long-term patency of the grafted radial artery was evaluated over more than a 5-year period (mean 7.2 years) in 20 of these patients by using magnetic resonance angiography or conventional angiography. There was no late occlusion of the graft in any of these cases. Stenotic graft changes were observed in two cases.

Spontaneous occlusion of supraclinoid aneurysms after the creation of extra-intracranial bypasses using long grafts: report of two cases

OBJECTIVE

We describe two cases of giant supraclinoid aneurysms, treated by means of saphenous vein grafting between the external carotid artery and the middle cerebral artery, which unexpectedly spontaneously occluded.

CLINICAL PRESENTATION

Two patients presented with subarachnoid hemorrhage and headache, respectively. In the first case, angiography showed an aneurysm of the right internal carotid artery (ICA), which had been treated by clipping. Repeat angiography showed a giant aneurysm of the right ICA, the formation of which was probably caused by sliding of the clip that had been applied during the previous operation. The patient was operated on again, but it was impossible to exclude the aneurysm because no clear neck could be identified. In the second case, magnetic resonance imaging and cerebral angiography showed a large, partially thrombosed aneurysm of the supraclinoid segment of the left ICA.

TECHNIQUE

In view of the patients' ages and the statuses of compensatory circulation, each patient underwent cerebral revascularization with a long saphenous vein graft placed between one branch of the middle cerebral artery and the external carotid artery, in anticipation of subsequent endovascular treatment of the aneurysm and/or closure of the ICA in the neck. Postoperative angiography demonstrated spontaneous occlusion of the aneurysms.

CONCLUSION

Thrombosis of an aneurysm may occur spontaneously or after explorative surgery. However, it should be remembered that spontaneous occlusion of an aneurysm may be induced or favored by hemodynamic vascular alterations that take place inside the aneurysm after a high-flow extra-intracranial bypass has been created.

Vascular reconstruction using interposed small vessels

OBJECTIVE

This study presents the relationship between the patency of short-vessel graft bypasses and their diameter/length.

METHODS

The authors performed interposed graft bypass operations using small vessels for four patients with moyamoya disease, six patients with cerebral thrombosis, and one patient with aortitis syndrome. The donor artery was the superficial temporal artery (10 patients) or the occipital artery (1 patient), and the recipient artery was the cortical branch of the middle cerebral artery (8 patients) or the cortical branch of the anterior cerebral artery (3 patients). The interposed graft used between these donor and recipient vessels was the superficial temporal vein (seven patients), the superficial temporal artery (three patients), or the epigastric artery (one patient).

RESULTS

Good patency of the graft was confirmed for 7 of these 11 patients. Regarding the relationship between the diameter/length and the patency, we found that long-term patency could not be expected when the discriminant function of y = (15.39 x diameter) - (0.35 x length) - 14.37 was below zero.

CONCLUSION

Short-vessel graft bypass is a practical option for cerebral revascularization surgery when short large vessels are used.

Direct surgery of carotid cavernous fistulae and dural arteriovenous malformations of the cavernous sinus

OBJECTIVE

To save the patency of the internal carotid artery (ICA) during the treatment of carotid cavernous fistulae or cavernous sinus dural arteriovenous malformations, direct surgery of the cavernous sinus after failure of endovascular treatment was attempted in this study.

METHODS

A total of 78 patients with carotid cavernous fistulae or cavernous sinus dural arteriovenous malformations were treated. Obliteration of the fistulous rent and preservation of the ICA were the therapeutic goals. All patients, except one in whom acute bleeding occurred, received endovascular treatment as the first treatment. In 18 (23.4%) of these 77 patients, it was not possible to obliterate the fistulous rents without sacrificing the ICAs. The 18 patients and the 1 patient with acute bleeding underwent direct surgery to open the cavernous sinus.

RESULTS

Various methods, including suturing or clipping the fistulae, sealing the fistulae with fascia and acrylate glue, and packing the cavernous sinus were applied. In each of three complicated cases, the cavernous segment of the ICA was trapped and an intracranial bypass from the petrous segment to the supraclinoid segment was performed. There was nor mortality, and the most common morbidity was transient oculomotor palsy, which occurred in eight patients. Follow-up angiography revealed that the ICAs or bypass grafts were thrombosed in 5 of the 19 patients who had undergone surgery.

CONCLUSION

In this series, the overall ICA patency rate of patients who underwent embolization and surgery was 94%, and the obliteration rate of the fistulae was 100%. Direct surgery of the cavernous sinus as a complimentary treatment of embolization can increase the preservation rate of the ICA.

Results of surgery for head and neck tumors that involve the carotid artery at the skull base

To evaluate the results of surgery in patients with head and neck cancers that involved the internal carotid artery at the skull base the authors retrospectively reviewed a consecutive series of 17 patients who underwent surgery at Mount Sinai Hospital over a 4-year period. In general, patients who underwent tumor resection with carotid preservation had less advanced disease (two of seven tumors were recurrences) than patients who underwent tumor resection with carotid sacrifice (seven of 10 tumors were recurrences). Of seven patients who underwent resection with carotid preservation, six had good outcomes (five patients alive in good condition, one dead at 2.2 years) and none had strokes. Of seven patients who underwent resection with carotid sacrifice and bypass, five had good outcomes (four alive in good condition, one dead at 2.5 years with no local recurrence) and two suffered graft occlusions that led to strokes, one of which was major and permanently disabling. Of three patients who underwent resection with carotid sacrifice and ligation without revascularization, there were no good outcomes: all three patients died within 6 months of surgery, two having suffered major permanently disabling strokes. The overall results (11 [65%] of 17 with good outcomes at an average follow-up period of 2.1 years) compared very favorably with historical nonsurgical controls. The authors conclude that tumor resection with carotid preservation carries the lowest risk of stroke and should usually be the treatment of choice. For patients with more advanced and recurrent disease, in whom it is believed that carotid preservation would prevent a safe and oncologically meaningful resection, carotid sacrifice with carotid bypass may be a useful treatment option. Carotid sacrifice without revascularization seems to be the treatment option with the least favorable results.

Middle cerebral artery revascularization. Anatomical studies and considerations on the anastomosis site

In the surgical management of skull base lesions and vascular diseases such as giant aneurysms, involvement of the internal carotid artery may require the resection or the occlusion of the vessel. The anastomosis of the external carotid artery and the middle cerebral artery with venous graft may be indicated to re-establish the blood flow. To determine the best suture site in the middle cerebral artery, an anatomical study was carried out. Fourteen cerebral hemispheres were analysed after the injection of red latex into the internal carotid artery. The superior and inferior trunk of the main division of the middle cerebral artery have more than 2 mm of diameter. They are superficial allowing an anastomosis using a venous graft. The superior trunk has a disadvantage, it gives rise to branches for the precentral and post-central giri. The anastomosis with the inferior trunk presents lower risk of neurological deficit even though the angular artery originates from it.

Microsurgical anatomy of the infratemporal fossa as viewed laterally and superiorly

OBJECTIVE

Benign tumors involving cavernous sinus, trigeminal nerve, and middle cranial fossa occasionally extend to the infratemporal fossa (ITF). In this study, we describe the microsurgical anatomy and dissection of the ITF, as viewed laterally and superiorly. We also describe a new bypass graft to the supraclinoid internal carotid artery using the internal maxillary artery (IMA), which is found in the ITF.

METHODS

Twelve cadaver specimens were used. Dissection required zygomatic arch osteotomy, downward displacement of the temporalis muscle, extensive subtemporal craniectomy, and mild elevation of the temporal lobe together with the dura.

RESULTS

The anatomic relationships between the lateral and medial pterygoid muscles and the neurovascular bundle of the ITF are demonstrated. The neurovascular bundle contains the IMA, which runs horizontally, and the main branches of the mandibular nerve, which run vertically. The course and anatomic variations of the IMA and inferior alveolar, lingual, auriculotemporal, and buccal nerves are shown. The distal IMA was quite tortuous and, when the artery straightened, we were able to perform a tension-free in situ IMA graft to the supraclinoid carotid artery in 9 of 12 specimens.

CONCLUSIONS

Knowledge of the anatomy of the ITF is a prerequisite for tumor resection in this area. The IMA may serve as a bypass graft to the supraclinoid internal carotid artery if the cavernous or petrous carotid artery is involved by tumor and needs to be sacrificed.