Cervical-to-petrous internal carotid artery bypass procedure. Technical note

[Anatomical bases of brain revascularization: choosing an extra-intracranial bypass option]

Surgical brain revascularization is an important treatment for acute or chronic ischemia, intracranial aneurysms and skull base tumors. Individual anatomy of brain vessels should be clearly understood for this procedure. Variants of collateral cerebral blood flow in patients with cerebrovascular diseases depend on individual characteristics of circle of Willis and reserve mechanisms of collateral circulation. These anatomical variations require careful preoperative planning to choose the optimal revascularization option.

Exercise, redox system and neurodegenerative diseases

Regular exercise induces a wide range of redox system-associated molecular adaptive responses to the nervous system. The intermittent induction of reactive oxygen species (ROS) during acute exercise sessions and the related upregulation of antioxidant/repair and housekeeping systems are associated with improved physiological function. Exercise-induced proliferation and differentiation of neuronal stem cells are ROS dependent processes. The increased production of brain derived neurotrophic factor (BDNF) and the regulation by regular exercise are dependent upon redox sensitive pathways. ROS are causative and associative factors of neurodegenerative diseases and regular exercise provides significant neuroprotective effects against Alzheimer's disease, Parkinson's disease, and hypoxia/reperfusion related disorders. Regular exercise regulates redox homeostasis in the brain with complex multi-level molecular pathways.

Clinical utility and versatility of the petrous segment of the internal carotid artery in revascularization

Direct approaches to high cervical lesions, including tumors and aneurysms, carry significant risks. This renders alternative approaches desirable, with vascular disease amenable to exclusion and revascularization to the intracranial circulation, including the petrous or supraclinoid segments of the internal carotid artery (ICA). The cervicopetrous ICA bypass via saphenous venous grafting has proven an effective strategy for treating and excluding these lesions. In current practice, this is performed via an extradural subtemporal approach to access the petrous segment of the ICA and a cervical incision for access to the cervical ICA. The venous graft is alternately tunneled subcutaneously or in situ through the cervical ICA, with the latter eschewing external compression, kinking, and torsion, which increases risk of graft thrombosis with the former. Maxillary or middle meningeal arteries may also serve as donors to the petrous ICA. Moreover, the petrous ICA may be used as a donor in revascularization procedures, to the supraclinoid segment of the ICA and the middle cerebral artery, with petrous supraclinoid and petrous-MCA bypasses described. Clinical utility and operative approaches bypassing to or from the petrous ICA in revascularization procedures are reviewed and discussed.

Revascularization and Aneurysm Surgery

BACKGROUND:

Given advances in endovascular technique, the indications for revascularization in aneurysm surgery have declined.

OBJECTIVE:

We sought to define indications, outline technical strategies, and evaluate the outcomes of patients treated with bypass in the endovascular era.

METHODS:

We retrospectively reviewed all aneurysms treated between September 2006 and February 2013.

RESULTS:

We identified 54 consecutive patients (16 males and 39 females) with 56 aneurysms. Aneurysms were located along the cervical internal carotid artery (ICA) (n = 1), petrous/cavernous ICA (n = 1), cavernous ICA (n = 16), supraclinoid ICA (n = 7), posterior communicating artery (n = 2), anterior cerebral artery (n = 4), middle cerebral artery (MCA) (n = 13), posterior cerebral artery (PCA) (n = 3), posterior inferior cerebellar artery (n = 4), and vertebrobasilar arteries (n = 5). Revascularization was performed with superficial temporal artery (STA) to MCA bypass (n = 25), STA to superior cerebellar artery (SCA) (n = 3), STA to PCA (n = 1), STA-SCA/STA-PCA (n = 1), occipital artery (OA) to PCA (n = 2), external carotid artery/ICA to MCA (n = 15), OA to MCA (n = 1), OA to posterior inferior cerebellar artery (n = 1), and in situ bypasses (n = 8). At a mean clinical follow-up of 18.5 months, 45 patients (81.8%) had a good outcome (Glasgow Outcome Scale 4 or 5). There were 7 cases of mortality (12.7%) and an additional 9 cases of morbidity (15.8%). At a mean angiographic follow-up of 17.8 months, 14 bypasses were occluded. Excluding the 7 cases of mortality, the majority of aneurysms (n = 42) were obliterated. We identified 7 cases of residual aneurysm and recurrence in 6 patients at follow-up.

CONCLUSION:

Given current limitations with existing treatments, cerebral revascularization remains an essential technique for aneurysm surgery.

Simultaneous approach of internal carotid artery revascularization at the base of the skull and coronary arteries bypass without extracorporeal circulation

The best surgical approach for the treatment of patients with severe cerebral artery disease and simultaneous serious coronary artery disease remains controversial. In this report, we present a case of a 65-year-old man admitted to the hospital with unstable angina. Triple coronary artery obstructive disease and severe right internal carotid artery stenosis in the retroparotid region were diagnosed. A combined, simultaneous surgical procedure was performed. A lesion located in the retroparotid space required an approach by a presternocleidomastoid cervicotomy extended distally. Venous grafting of the internal carotid artery was performed. After carotid reconstruction, the three coronary arteries were revascularized without extracorporeal circulation. The patient showed a satisfactory postoperative outcome.

Petrous carotid artery's in situ bypass: anatomic study

The purpose of our study was to reveal the possibility of cervical-to-petrous carotid artery in situ bypass with maximum preservation of cranial nerves. Four human cadavers prepared in formalin were investigated. Eight surgical approaches were used (bilateral exposure on each cadaver). The skin incision started from the level of the temporomandibular joint. The VII, IX, X, and XII cranial nerves, starting from the stylomastoid angle, were maximally preserved. Resection of the styloid process, subluxation of the mandibular joint, and milling of tympanic bone revealed the petrous carotid artery. Exposure of the carotid bifurcation was performed with a mini-skin incision. After dividing the petrous internal carotid artery (ICA) and the cervical ICA, the cervical ICA was dilated using a Fogarty catheter to simulate aneurysmal dilatation. The patient's saphenous vein after stripping was utilized for the bypass. The vein was passed into the lumen of the dilated cervical ICA, and a cervical-to-petrous carotid bypass was performed. In each case, the described technique made it possible to expose the intrapetrous carotid artery adequately. In two cases it was impossible to make a luxation, and therefore the mandibular branch was resected. The vertical segment's mean length was 12 mm (range 10-15 mm). In all cases, the VII, IX, X, and XII cranial nerves were preserved maximally. The main points of the approach are luxation of the mandibular articulation and milling of the tympanic bone. Our study in cadavers suggests the possibility of petrous carotid artery bypass without exposing the cervical ICA.

Increasing exposure of the petrous internal carotid artery for revascularization using the transzygomatic extended middle fossa approach: a cadaveric morphometric study

OBJECTIVE

When internal carotid artery (ICA) sacrifice is planned in the management of difficult tumors or aneurysms at the cranial base, the petrous ICA may be a useful site for anastomosis for interpositional vascular bypass. However, exposure of the artery and performing an anastomosis in this region may be technically challenging because of the narrow working corridor. The authors describe a transzygomatic extended middle fossa approach that maximizes the exposure of the petrous ICA for performing the difficult anastomosis.

METHODS

Bilateral dissections were performed on eight silicone-injected cadaveric head specimens. Exposure of the entire petrous ICA (horizontal segment, genu, and vertical segment) using the transzygomatic extended middle fossa approach was performed by the following steps. A frontotemporal craniotomy was performed followed by a zygomatic osteotomy. The temporal lobe dura was elevated extradurally to expose the posterior cavernous sinus and floor of the middle fossa. The middle fossa rhomboid was identified, which is bordered by V3 anteriorly, the GSPN laterally, the arcuate eminence posteriorly, and the petrous edge medially. Bone drilling was performed in the middle fossa rhomboid and Glasscock's triangle with care not to violate the cochlea. The horizontal and vertical segments of the petrous ICA were skeletonized entirely and mobilized from carotid canal. The V3 segment of the trigeminal nerve was retracted anteriorly to obtain more distal exposure of the ICA. An osteoplastic bone flap of the middle fossa floor lateral to the ICA was removed to increase the working space. A morphometric analysis was performed, quantifying the petrous ICA exposure, the surgical working corridor, and the angles of exposure.

RESULTS

On average, the length of the horizontal petrous ICA exposed was 9.2 +/- 1.0 mm (range, 8.0-11.0 mm). Anterior retraction of V3 provided an additional 4.3 +/- 0.4 mm of carotid exposure (46.7% increase; P < 0.05). The length of the genu was on average 3.6 +/- 0.4 mm (range, 3.0-4.0 mm), and the length of the vertical segment of the petrous ICA was 13.1 +/- 2.0 mm (range, 10.0-15.0 mm). The average depth of the petrous ICA from the outer surface of the temporal bone was 30.6 +/- 1.1 mm (range, 30.0-33.0 mm) at the V3-ICA junction and 27.2 +/- 0.7 mm (range, 26.0-28.0 mm) at the ICA genu. The average diameter of the inner working corridor was 24.2 +/- 3.0 mm (range, 21.5-30.0 mm). Removal of the zygoma increased the outer working corridor from an average distance of 24.4 +/- 3.8 mm to 33.4 +/- 3.4 mm (36.9% increase in exposure; P < 0.05). The average angle of exposure was 66.5% greater (P < 0.05) with zygomatic arch removal (39.3 +/- 4.9 degrees) than without zygomatic arch removal (23.6 +/- 2.7 degrees).

CONCLUSION

The transzygomatic extended middle fossa approach provides a wide surgical corridor for maximal exposure of the petrous ICA with minimized temporal lobe retraction. This large exposure facilitates vascular anastomoses at the petrous ICA and provides working room to maneuver instruments. The middle fossa rhomboid is a key landmark to identify the petrous ICA and to avoid neuro-otologic structures.

Carotid artery resection and reconstruction: clinical experience of 28 consecutive cases

The aim of this study was to analyse the experience at a single institution in carotid artery resection with or without reconstruction performed as part of an oncological procedure or emergency haemostasis. A total of 28 patients were included in this retrospective study; 17 underwent ligation or resection of the carotid artery, and 11 underwent reconstruction of the carotid artery. The perioperative complications and surgical outcomes were recorded and analysed. Of the 17 patients with ligation or resection of the carotid artery, 4 developed neurologic deficit within 2 weeks postoperatively. Three patients with malignant tumours died 1 month (1) and 4 months (2) postoperatively. Of the 11 patients undergoing carotid reconstruction, no major cerebral complications were noted after operation. Colour Doppler showed patent vascular graft 1 year postoperatively in nine patients. Due to the higher complication rates both in short and long term with ligation or resection of the carotid artery, resection and revascularization of the carotid artery is advocated for patients with carotid artery involvement when possible.

Submandibular-Infratemporal Interpositional Carotid Artery Bypass for Cranial Base Tumors and Giant Aneurysms

OBJECTIVE:

Cerebral revascularization is an important strategy in the surgical management of some complex cranial base tumors and unclippable aneurysms. A high-flow bypass may be necessary in planned carotid occlusion or sacrifice. The cervical-to-supraclinoid internal carotid artery bypass or cervical carotid-to-middle cerebral artery bypass are useful procedures to bypass lesions at the base of the cranium. We describe technical modifications of the submandibular-infratemporal interpositional saphenous vein (or radial artery) graft bypass technique specifically designed to avoid removal of the zygoma.

METHODS:

The saphenous vein or radial artery interpositional graft is tunneled through a burr hole created in the floor of the middle fossa via a submandibular-infratemporal route avoiding removal of zygoma and attachments of the masseter or temporalis muscles.

RESULTS:

The technique is demonstrated in one patient with removal of a malignant cavernous sinus tumor and in another patient with an unclippable giant carotid bifurcation aneurysm.

CONCLUSION:

The advantages of this approach include preservation of the facial anatomy and creation of a short and safe route for passage of the saphenous vein or radial artery graft.

Revascularization with saphenous vein bypasses for complex intracranial aneurysms

Most intracranial aneurysms can be managed with either microsurgical clipping or endovascular coiling. A subset of complex aneurysms with aberrant anatomy or fusiform/dolichoectatic morphology may require revascularization as part of a strategy that occludes the aneurysm or parent artery or both. Bypass techniques have been invented to revascularize nearly every intracranial artery. An aneurysm that will require a saphenous vein bypass is one that cannot be treated with conventional microsurgical clipping or endovascular coiling and also requires deliberate sacrifice of a major intracranial artery as part of the alternative treatment strategy. In the past 7 years the senior author (MTL) has performed a total of 110 bypasses, of which 46 were for aneurysms. Twenty-two of these patients received high-flow extracranial-to-intracranial bypasses using saphenous vein grafts, of which 16 had aneurysms that were giant in size. We review the indications for saphenous vein bypasses for complex intracranial aneurysms, surgical techniques, and clinical management strategies.

Revascularization for complex skull base tumors

We discuss revascularization techniques for complex skull base lesions utilizing high-flow arterial bypass. At present, the radial artery is the donor graft utilized in most circumstances at our institution. The knowledge of revascularization techniques is very important to achieve radical resection in lesions where arterial compromise is documented.

Possibility of middle meningeal artery-to-petrous internal carotid artery bypass: an anatomic study

The possibility of creating a middle meningeal artery (MMA)-to-petrous internal carotid artery (ICA) bypass was investigated in six cadavers (bilaterally). Such a procedure could be used to treat patients with high cervical vascular lesions and those with tumors of the infratemporal fossa invading the high cervical ICA. After a frontotemporal craniotomy, the foramen spinosum and foramen ovale were exposed extradurally. Immediately posterior to the foramen ovale and medial to the foramen spinosum, the petrous portion of the ICA was exposed with a diamond-tipped drill. The MMA was lifted from its groove, and a sufficient length was transected to perform a bypass with the petrous ICA medially. The mean width of the MMA at the site of anastomosis was 2.3 +/- 0.35 mm. The mean length of MMA from the foramen spinosum to the site of the anastomosis was 9.6 +/- 1.7 mm. Based on these measurements, width and length of MMA appear to be sufficient for a bypass with petrous ICA.

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.

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.

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 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.

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.

Treatment of malignant neoplasms of the lateral cranial base with the combined frontotemporal-anterolateral approach: five-year follow-up

Technical advances in accessing the lateral cranial base have permitted disease in this area previously deemed inoperable to be resected. The procedures required to effect an oncologically adequate resection are often long and accompanied by the potential for serious, even life-threatening, complications. Although it has been demonstrated that such disease can be extirpated, the question of whether such heroic surgery improves long-term survival remains unanswered. We retrospectively reviewed the records of 25 patients who underwent a combination of frontotemporal craniotomy with other, more conventional, anterolateral procedures (eg, infratemporal fossa approach, maxillectomy, orbitectomy, mandibulopharyngectomy) to resect stage IV malignant disease of the lateral to midcranial base between 1983 and 1990. Perioperative deaths occurred in 2 patients, 1 patient died of unrelated causes free of disease, and 2 patients were lost to follow-up, leaving 20 patients with a minimum 5-year evaluation. Five (25%) of the 20 patients we monitored were free of disease. Of those patients in whom recurrent disease developed, local control was achieved in about 50%; however in 80% of those with recurrence, metastatic disease developed. Surgical treatment of selected stage IV malignant disease of the lateral to midcranial base appears to have provided long-term disease-free survival to 25% of patients in this series who would otherwise have had little hope of survival.

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.

Anatomic basis for the treatment of aneurysms of the upper cervical segment of the internal carotid artery by extra-intracranial cervico-petrous bypass with inverted "in situ" saphenous vein graft

In the surgical treatment of aneurysms of the upper cervical portion of the internal carotid a., exclusion of the affected vascular segment combined with an extra-anatomic cervico-petrous bypass using a vein graft (great saphenous v.) may be considered. One of the problems specific to these extra-anatomic bypasses is associated with the sub-cutaneous positioning of the vein graft, exposing it to risks of angulation, torsion or extrinsic compression that may lead to early venous thrombosis. We suggest an alternative technique using the principle of telescoping and consisting of positioning the vein graft within the cervical portion of the artery ("in situ" bypass). The cervical portion of the ICA may be used as a tunnel for the vein graft since there are no collateral arterial branches at this level. The technical features of such a bypass are defined by means of an anatomo-surgical study in the cadaver: exposure of the petrous portion of the internal carotid a. in its horizontal segment by subtemporal access, exposure of the ICA in the neck, transverse arteriotomies of the ICA, angioplasty with a Fogarty balloon, intracarotid telescoping of a saphenous vein graft from the cervical to the petrous region, distal end-to-end anastomosis between the vein graft and the petrous portion of the ICA, and proximal end-to-end anastomosis between the vein graft and the cervical portion of the ICA.

Reversed-flow saphenous vein grafts for cerebral revascularization. Technical note

The authors sought to create a saphenous vein interposition graft to be used in cerebral bypass procedures that would be more physiologically appropriate than standard vein grafts and would provide a better match between the graft and recipient vessels at the anastomotic sites. The saphenous vein graft was prepared by lysing the valves with a valvulotome. The blood flow could then be reversed in the vein, allowing it to be used in either direction as a bypass graft. An illustrative case including angiograms that confirm good patency and blood flow through the reversed-flow bypass graft is presented. It is concluded that the reversed-flow saphenous vein graft provides a more physiologically suitable conduit than standard vein grafts. Lysis of the valves allows the graft to be used in an orientation that takes advantage of the natural tapering of the vein to produce a better match with the recipient vessels at the anastomotic sites. Minimizing diameter changes at the proximal and distal anastomoses helps reduce turbulence, which has been implicated as a cause of early graft failure and thrombosis.

Surgical exposure of the petrous internal carotid artery: practical application for skull base surgery

When exposing the horizontal petrous carotid artery in preparation for intrapetrous carotid bypass, the surgeon has no definite landmarks to localize the perimeter of the cochlea. The results of this study provide a practical, consistent, and safe method to maximize carotid artery exposure while minimizing cochlear injury. We measured the carotid-cochlea distance (mean, 4.3 mm) and the carotid-cochlear angle (mean, 10.8 degrees) in 33 temporal bones in which the extended middle fossa approach had been performed. We correlated this distance to the width of a Sheehy weapon knife, which can be easily measured intraoperatively. Twenty-five temporal bones were imaged prior to surgical exposure using a new computed tomography (CT) protocol that can be used for preoperative assessment of the carotid-cochlear anatomy. The carotid-cochlea distance and carotid-cochlear angle measured on CT are compared with postsurgical measurements.

Gunshot wounds of the internal carotid artery at the skull base: management with vein bypass grafts and a review of the literature

BACKGROUND

Penetrating trauma to the skull base and distal cervical internal carotid artery (ICA) can result in occlusion or pseudoaneurysm formation. The appropriate management strategy for these rare lesions is controversial and includes observation, anticoagulation, carotid ligation, balloon occlusion, or revascularization.

METHODS

We present the management and outcomes of four consecutive patients, two with pseudoaneurysms and two with acute occlusions, after injury to the distal cervical/petrous ICA from gunshot wounds. Preoperative assessment determined intracranial collateral flow patterns and the patency of the distal portion of the petrous ICA.

RESULTS

Two patients underwent cervical-to-petrous ICA vein bypass grafts without neurologic complications. Both grafts remain patent without evidence of emboli at 2 years and 3 months, respectively. Both of the conservatively managed patients died, one from a massive cerebral infarction and the other from intracerebral hemorrhage.

CONCLUSIONS

These cases underscore the need for an aggressive approach to the assessment and management of patients with penetrating vascular skull-base injuries. Although the optimal treatment of remains controversial, when the goal is exclusion of the injured portion of the carotid artery and revascularization, the cervical to petrous ICA vein bypass graft is a valuable management option that can reduce the potential morbidity and mortality from acute ischemic or delayed embolic or hemorrhagic complications, provide immediate restoration of high flow, and allow good surgical access with minimal risk to intracranial structures.

Cervical-to-petrous internal carotid artery saphenous vein in situ bypass for the treatment of a high cervical dissecting aneurysm: technical case report

OBJECTIVE AND IMPORTANCE

We describe a novel cervical-to-petrous internal carotid artery (ICA) saphenous vein in situ bypass for the treatment of a high cervical dissecting aneurysm. The cervical ICA has no major collateral branches and can be used as a tunnel for the vein graft.

CLINICAL PRESENTATIONS

A 25-year-old man was involved in a car accident. A cerebral angiogram revealed a right ICA dissection with aneurysm formation at the C1-C2 level. The patient recovered fully and was anticoagulated. Six months after the initial angiogram, a second angiogram disclosed ICA stenosis (80%) and persistence of the traumatic dissecting aneurysm. Definitive surgical bypass was considered the most appropriate course of action.

TECHNIQUE

The horizontal portion of the petrous ICA was exposed by an extradural subtemporal approach. The cervical arteries were exposed by a separate surgical incision. After dividing the petrous ICA and the cervical ICA, the cervical ICA was dilated using a Fogarty balloon embolectomy catheter. A saphenous vein graft was inserted inside the lumen of the cervical ICA and was anastomosed to the ICA end-to-end both proximally and distally (cervical-to-petrous ICA in situ bypass). The graft was patent on the follow-up angiogram.

CONCLUSION

We describe a new technique that could be considered an alternative to the classical extra-anatomic cervical-to-petrous ICA bypass procedures.

External carotid-to-middle cerebral bypass in the treatment of complex internal carotid injury

Patients with penetrating carotid injuries above C2 present special challenges to the cerebrovascular surgeon. A subgroup of patients may lack the vascular collaterals necessary to tolerate carotid sacrifice or prolonged ischemia during direct carotid repair. We present a technique of extracranial-intracranial (EC-IC) saphenous vein bypass in two patients with high cervical and skull base carotid injuries and poor vascular collaterals. This technique allows preservation of internal carotid flow during the proximal anastomosis. Interruption of cerebral blood flow is limited to the duration required for a distal intracranial anastomosis and is confined to the territory supplied by a single middle cerebral branch. The procedure eliminates systemic anticoagulation, includes trapping of the injured segment of the internal carotid artery, and restores a volume of flow similar to that of the internal carotid artery. It is a valuable adjunct in this specific population of patients with high carotid injuries who cannot tolerate even brief periods of temporary occlusion or in whom clinical urgency precludes an endovascular trial occlusion.

Revascularization and aneurysm surgery: current techniques, indications, and outcome

Revascularization is an important component of treatment for complex aneurysms that cannot be directly clipped and instead require parent vessel occlusion. A consecutive series of 61 patients with 63 aneurysms requiring cerebral revascularization is presented. Aneurysms were located along the petrous internal carotid artery (ICA) (n = 5), the cavernous ICA (n = 16), the supraclinoid ICA (n = 12), the middle cerebral artery (n = 17), the anterior cerebral artery (n = 4), the vertebral artery/posterior inferior cerebellar artery (n = 5), and the midbasilar artery (n = 4). Aneurysms were treated by direct clipping (n = 8), trapping (n = 28), proximal vessel occlusion (n = 9), distal vessel occlusion (n = 1), excision (n = 15), and thrombotic occlusion (n = 2). Revascularization was performed with petrous to supraclinoid ICA bypass (n = 12), superficial temporal artery to middle cerebral artery bypass (n = 15), superficial temporal artery to middle cerebral artery bypass with saphenous graft (n = 5), superficial temporal artery to superior cerebellar artery bypass (n = 4) long saphenous bypass (n = 11), in situ bypass (n = 3), and primary reanastomosis (n = 13). Fifty-seven patients (93%) had good outcomes, and one patient died (surgical mortality, 2%). This experience demonstrates that revascularization can be performed with low morbidity and mortality. We think that the cumulative risks of not performing revascularization in patients who tolerate ICA balloon occlusion exceed the surgical risk of revascularization. We therefore favor revascularization in patients with complex aneurysms treated by surgical arterial occlusion.

Surgical treatment of extracranial internal carotid artery dissecting aneurysms

Aneurysms of the extracranial internal carotid artery (ICA) are uncommon. A significant proportion of such aneurysms are now recognized to be caused by arterial dissection. In some patients, surgical treatment may become necessary. The surgical treatment of 22 patients with spontaneous or traumatic dissecting aneurysms arising from the extracranial ICAs is reviewed. The mean age of the 7 women and 15 men was 39 years. The aneurysm arose from the proximal third of the extracranial ICA in 1 patient, from the middle third in 1 patient, and from the distal third in 20 patients. Five patients underwent cervical carotid ligation; in 13 patients, the aneurysms were resected, and the ICAs were reconstructed, and 4 patients underwent cervical-to-intracranial ICA bypasses. There were 2 postoperative strokes (9%). Facial and lower cranial nerve palsies were commonly seen after high cervical exposure, but these cranial nerve palsies were transient. There were no long-term neurological sequelae during a mean follow-up of 6.2 years. In our relatively limited experience, extracranial ICA dissecting aneurysms can be treated with acceptable morbidity using a variety of techniques. However, the indications for surgical intervention in these aneurysms remain limited.