High-flow bypass using nonocclusive excimer laser-assisted end-to-side anastomosis of the external carotid artery to the P1 segment of the posterior cerebral artery via the sylvian route. Technical note

Long-term feasibility of the new sutureless excimer laser-assisted non-occlusive anastomosis clip in a pig model

BACKGROUND

High flow bypass surgery can be a last resort procedure for patients suffering from complex neurovascular pathology. Temporary occlusion of a recipient artery in these patients could result in debilitating neurological deficits. We developed a sutureless, mechanical anastomotic connection device, the SELANA clip (Sutureless Excimer Laser-Assisted Non-occlusive Anastomosis clip: SEcl). In the present study, we aim to determine the long-term non-inferiority of the SEcl technique compared with historical data of the conventional ELANA anastomosis technique.

METHODS

A total of 18 SEcl bypasses were created on the carotid artery in a porcine model in 6 different survival groups. Mean application times, flap retrieval rates, hemostasis, patency, flow, endothelialization, and remodeling were assessed.

RESULTS

The mean application time of the SEcl anastomoses was 15.2 ± 9.6 min, which was faster compared with the conventional ELANA anastomoses. The flap retrieval rate of the SEcl anastomoses was 86% (32/37). Direct hemostasis was achieved in 89% (33/37) SEcl anastomoses. Patency in all surviving animals was 94% (17/18). Bypass flow after six months was 156.5 ± 24.7 mL/min. Full endothelialization of the SEcl pins was observed after 3 weeks.

CONCLUSION

The SEcl technique is not inferior to the ELANA technique regarding patency, flap retrieval rate, flow, and endothelialization. On the basis of a significantly shorter application time and superior hemostasis, the SEcl technique could be preferable over the ELANA technique. A pilot study in patients is a logical next step based on our current results.

Bypass Surgery for the Treatment of Dolichoectatic Basilar Trunk Aneurysms: A Work in Progress

BACKGROUND

The treatment of dolichoectatic basilar trunk aneurysms has been ineffectual or morbid due to nonsaccular morphology, deep location, and involvement of brainstem perforators. Treatment with bypass surgery has been advocated to eliminate malignant hemodynamics and to stabilize aneurysm growth.

OBJECTIVE

To validate that flow alteration with bypass and parent artery occlusion favorably impacts aneurysm progression.

METHODS

Surgical management evolved in 3 phases, each with different hemodynamic alterations.

RESULTS

During a 17-year period, 37 patients with dolichoectatic basilar trunk aneurysms were retrospectively identified, of whom 21 patients were observed, 12 treated immediately, and 4 selected for treatment after clinical progression. In phase 1, flow reversal was overly thrombogenic, despite heparin (N = 5, final mortality, 100%). In phase 2, flow reduction with intracranial-to-intracranial bypass was safer than flow reversal, but did not prevent progressive aneurysm enlargement (N = 3, final mortality 67%). In phase 3, distal clip occlusion of the basilar trunk aneurysm preserved anterograde flow in the aneurysm without rupture, but reduced flow threatened perforator patency, despite treatment with clopidogrel (N = 8, final mortality 62%).

CONCLUSION

Shifting treatment strategy for dolichoectatic basilar trunk aneurysms improved surgical (80% to 50%) and final mortalities (100% to 62%), with stabilization of aneurysms in the phase 3 survivors. Good outcomes are determined by perforator preservation and mitigating aneurysm thrombosis. Occlusion techniques with increased distal run-off seem to benefit perforators. The treatment of dolichoectatic basilar trunk aneurysms can advance through concentrated management in dedicated centers, concerted efforts to study morphology and hemodynamics with computational methods, and widespread collection of registry data.

ABBREVIATIONS

4D PC-MRI, time-resolved phase-contrast MRIAICA, anterior inferior cerebellar arteryCE-MRA, high-resolution contrast-enhanced MR angiographyEC-IC, extracranial-to-intracranial bypassMCA, middle cerebral arteryMR, magnetic resonancemRS, modified Rankin ScalePCA, posterior cerebral arteryPICA, posterior inferior cerebellar arterySCA, superior cerebellar arterySTA, superficial temporal arteryVA, vertebral artery.

Giant and complex aneurysms treatment with preservation of flow via bypass technique

Due to their anatomical characteristics and the complexity of the procedures required to obtain their complete occlusion, the treatment of giant intracranial aneurysms is a real challenge. Direct reconstructive strategies, whether by interventional neuroradiology (coils, stents) or microsurgical (clipping) means, are not always applicable and, in patients that would not tolerate parent or collateral artery sacrifice, the adjunction of a revascularization procedure using a bypass technique might be necessary. Cerebral arterial bypasses can be classified according to their function (3 types: flow replacement, flow reversal or protective), the branching mode of the graft used (3 types: pedicled, interpositional or in situ), the sites of anastomosis (2 types: extracranial-intracranial or intracranial-intracranial) and the class of flow they are supposed to provide (3 types: low-, intermediate- or high-flow). In this article, the authors review the different aspects in the management of patients with a giant intracranial aneurysm using a bypass: preoperative work-up, types of bypass and indications, surgical techniques and results.

"How I Do It:" Non-occlusive High Flow Bypass Surgery

Giant intracranial aneurysms are a formidable challenge for treatment, considering their grim prognosis. Until lately, endovascular treatment options have been disappointing, and neurosurgical treatment results are by far the most promising. In the neurosurgical treatment of giant intracranial aneurysms, the non-occlusive nature of the ELANA anastomosis technique is a major advantage in flow replacement bypass surgery where large proximal arteries with higher flows need to be replaced or reconstructed. The construction of a deep intracranial anastomosis using the ELANA technique needs less vessel exposure than when using a conventional occlusive technique. This extra advantage facilitates the construction of anastomoses even on the ICA, MCA, ACA, P1, P2, SCA or BA, using the trans-Sylvian route only, without major skull base surgery. Several different types of EC-IC and IC-IC flow replacement bypass are now safely applicable due to the non-occlusive character of this technique.Future improvements of the technique are focused on sutureless applications, graft improvements and Flow Model Simulation. It is clear that not only conventional bypass techniques, but also, and even especially, the ELANA bypass technique, are of great value in the treatment of giant aneurysms.

Reconstructive endovascular treatment of fusiform and dissecting basilar trunk aneurysms with flow diverters, stents, and coils

BACKGROUND AND PURPOSE

Patients with fusiform basilar trunk aneurysms have a poor prognosis. Reconstructive endovascular therapy is possible with modern devices. We describe the clinical presentation, radiologic features, and clinical outcome of 13 patients with fusiform basilar trunk aneurysms treated with flow diverters, stents, and coils.

MATERIALS AND METHODS

Of the 13 patients, 7 were men and 6 were women with a mean age of 59.7 years. Clinical presentation was SAH in 3 patients, mass effect on the brain stem in 4 patients, vertebral artery dissection in 1 patient, and the aneurysm was an incidental finding in 5 patients. Mean aneurysm size was 21 mm. All except 1 were large or giant aneurysms. Nine aneurysms were partially thrombosed.

RESULTS

Stents were used in all 13 patients, in 2 patients with additional flow diverters and in 11 patients with additional coils. In 4 patients, 1 vertebral artery was subsequently occluded with coils to decrease flow into the aneurysm. Of 13 patients, 9 had a good outcome with adequate aneurysm occlusion and stable size on follow-up of 6-72 months. One of 3 patients who presented with SAH died of a rebleed 1 month later. One other patient died soon after treatment of in-stent thrombosis, and another patient became mute after treatment. In 2 of 3 patients who presented with symptoms of mass effect, there was improvement at a follow-up of 6-24 months.

CONCLUSIONS

Reconstructive endovascular therapy of fusiform and dissecting basilar trunk aneurysms is feasible but carries substantial risks. The safety and effectiveness in relation to natural history has not yet been elucidated.

Patency, flow, and endothelialization of the sutureless Excimer Laser Assisted Non-occlusive Anastomosis (ELANA) technique in a pig model

OBJECT

The purpose of this study was to assess flow, patency, and endothelialization of bypasses created with the sutureless Excimer Laser Assisted Non-occlusive Anastomosis (SELANA) technique in a pig model.

METHODS

In 38 pigs, a bypass was made on the left common carotid artery (CCA), using the right CCA as a graft, with 2 SELANAs. Bypass flow was measured using single-vessel flowmetry. The pigs were randomly assigned to 1 of 12 survival groups (1, 2, 3, 4, 5, 6, 7, and 10 days; 2 and 3 weeks; and 3 and 6 months). One extra animal underwent the procedure and then was killed after 1 hour of bypass patency to serve as a control. Angiography was performed just before the animals were killed, to assess bypass patency. Scanning electron microscopy and histological studies were used to evaluate the anastomoses after planned death.

RESULTS

The mean SELANA bypass flow was not significantly different from the mean flow in the earlier ELANA (Excimer Laser Assisted Non-occlusive Anastomosis) pig study at opening and follow-up. Overall SELANA bypass patency (87%) was not significantly different from the ELANA patency of 86% in the earlier study. Complete SELANA endothelialization was observed after 2-3 weeks, compared with 2 weeks in the earlier ELANA study.

CONCLUSIONS

The SELANA technique is not inferior to the current ELANA technique regarding flow, patency, and endothelialization. A pilot study in patients is a logical next step.

Experience in Using the Excimer Laser–Assisted Nonocclusive Anastomosis Nonocclusive Bypass Technique for High-Flow Revascularization

BACKGROUND

The excimer laser–assisted nonocclusive anastomosis (ELANA) technique enables large-caliber bypass revascularization without temporary occlusion of the parent artery.

OBJECTIVE

To present the surgical experience of 2 bypass centers using ELANA in the treatment of complex intracranial lesions.

METHODS

Between July 2002 and December 2007, 64 consecutive patients (37 in Germany and 27 in Finland) were selected for high-flow bypass surgery with ELANA. Modified Rankin Scale, a bypass success rate, and the success rate of the laser arteriotomy were assessed.

RESULTS

In 66 surgeries for 64 intent-to-treat patients, 58 ELANA procedures were completed successfully. A favorable outcome (postoperative modified Rankin Scale score less than or equal to preoperative modified Rankin Scale) at 3 months was achieved in 43 of 56 patients (77%) with anterior circulation lesions (37 of the 43 patients had aneurysms, 4 had ischemia, and 2 received a bypass before tumor removal) and only in 2 of 8 patients (25%) with posterior circulation aneurysms. Perioperative (< 7 days) mortality for anterior and posterior circulation aneurysms was 6% and 50%, respectively. At the 3-month follow-up, 12% and 63% of patients with anterior and posterior circulation aneurysms, respectively, were dead. The success rate of the laser arteriotomy was 70%. Another 14% were retrieved manually after a nearly complete laser arteriotomy.

CONCLUSION

The ELANA procedure requires a meticulous and careful operative technique. Morbidity and especially mortality rates, usually unrelated to ELANA, are comparable to those of contemporary series of conventional high-flow revascularization operations. This underscores the overall complexity of treating neurovascular pathologies by high-flow bypasses.

Microsurgery for Previously Coiled Aneurysms: Experience With 81 Patients

BACKGROUND:

Residual and recurrent intracranial aneurysms after endovascular treatment with Guglielmi detachable coils may necessitate a microsurgical occlusion.

OBJECTIVE:

To analyze the microsurgical technique and describe how the location, morphology, and appearance of the coiled aneurysm affect the technique.

METHODS:

We retrospectively analyzed 81 patients with 82 previously coiled aneurysms treated microsurgically at 2 Finnish neurosurgical university hospitals in Helsinki and Kuopio between July 1995 and August 2009. Seven videos were selected to demonstrate the microsurgical strategy in various locations.

RESULTS:

Fifty-eight aneurysms (71%) were located at anterior circulation and 24 (29%) at posterior circulation. Fifteen patients were operated on within the first month (early surgery) after coiling, whereas 66 were treated later (late surgery). Complete or partial removal of coils during surgery may facilitate clipping, but is significantly (P < .001) more difficult to accomplish in late surgery. Removal of coils may also increase the chance of poor outcome. Chance of poor outcome also increased with intraoperative aneurysm rupture, size of the aneurysm, and posterior circulation location. Good clinical outcome (same or better clinical condition 3 months after surgery) was achieved in 71 patients (88%). After microsurgery, 4 patients were severely disabled and 6 patients died, 3 of them because of poor clinical condition.

CONCLUSION:

Complete microsurgical occlusion of the residual aneurysm is possible. However, in large or giant aneurysms direct microsurgery is a challenging high-risk procedure, and we recommend that these patients be referred to a dedicated neurovascular center to minimize surgical complications. Even in experienced hands, use of different bypass procedures may be the best option for demanding growing lesions, especially those in the posterior circulation.

Experimental simplification of the excimer laser-assisted nonocclusive anastomosis (ELANA) technique

BACKGROUND

The excimer laser-assisted nonocclusive anastomosis (ELANA) technique facilitates the construction of an end-to-side anastomosis between a donor vessel and a recipient artery without the need to temporarily occlude the recipient artery.

OBJECTIVE

To test whether the surgically difficult ELANA technique can be simplified.

METHODS

In 42 rabbits, with the aorta as the recipient artery and human saphenous veins as donor grafts, we made 30 conventional ELANAs with 8 microsutures, 90 ELANAs with 4 microsutures (ELANA-4s), 40 ELANAs with 2 microsutures (ELANA-2s), and 90 sutureless ELANAs (SELANAs). SELANA involved a new ring design with 2 pins. ELANA-4, ELANA-2, and SELANA were each combined with 3 different sealants (Bioglue, Tachoseal, and Tisseel) and compared regarding application time, complications, and burst pressure.

RESULTS

The conventional ELANA was constructed in a mean of 14.8 +/- 2.6 minutes. All experimental anastomoses were constructed significantly faster; the ELANA-4 in a mean of 10.9 +/- 1.3 minutes, the ELANA-2 in a mean of 5.4 +/- 1.7 minutes, and the SELANA in a mean of 2.5 +/- 1.8 minutes. All ELANA and ELANA-4 anastomoses were sufficiently strong with a burst pressure > 200 mm Hg, except for 1 insufficiently sealed ELANA-4 anastomosis. ELANA-2 was sufficiently strong only with Bioglue, showing a burst pressure > 280 mm Hg. SELANA was sufficiently strong with Bioglue or TachoSil, showing a burst pressure > 260 mm Hg.

CONCLUSION

The ELANA technique can be simplified by reducing or even abandoning microsutures. Of the experimental anastomoses tested, we consider the SELANA technique combined with TachoSil of most potential benefit. Long-term survival studies will be performed in animals before we consider using any of these new techniques in patients.

Surgical and endovascular treatments for intracranial aneurysms

The goals of microsurgical and endovascular treatment of intracranial aneurysms are to prevent subarachnoid hemorrhage and/or eliminate mass effect symptoms. Debate has raged regarding which aneurysms to treat and with which technique or combination of techniques. It is our impression that studies that have assessed aneurysm natural history and treatment options are compromised by the inherent limitations of clinical trials, with many natural history studies likely underestimating rupture risk over long-term follow-up. Endovascular therapy and open neurosurgery should both be used strategically, and our current interest is in integrating these techniques in a fashion extending beyond the simplistic clip-versus-coil debate.

Giant Aneurysm Clipping Under Protection of an Excimer Laser–Assisted Non-occlusive Anastomosis Bypass

OBJECTIVE

To define the safety and clinical value of giant aneurysm clipping under protection of an excimer laser–assisted non-occlusive anastomosis (ELANA) bypass.

METHODS

We report 32 patients with an uncoilable intracerebral giant aneurysm, operated on with the aid of an ELANA protective bypass between January 1, 1994, and January 1, 2008. We retrospectively collected data from patient records. Follow-up data were updated by telephone interview. We defined a favorable outcome as a successfully treated aneurysm and a better or equal postoperative modified Rankin scale (mRS) score compared with the preoperative mRS.

RESULTS

In total 33 bypasses were constructed, of which 31 (94%) were patent during the rest of the procedure. The first failed bypass was salvaged during a second procedure. Of the second failed bypass, the ELANA anastomosis could be reused during second bypass surgery. All 32 aneurysms could be treated. The bypasses served as protection during temporary parent vessel occlusion (n = 24, 75%), control during aneurysm rupture (n = 3, 9%), and in all patients as an indicator for recipient artery narrowing during clip placement. Four bypasses (12%) eventually had to partially (n = 3) or fully (n = 1) replace recipient artery flow at the end of surgery. Postoperatively, 3 patients (9%) had a hemorrhagic complication and 2 patients (6%) had an ischemic complication. At long-term follow-up (mean, 6.1 ± 3.4 y), 28 patients (88%) had a favorable functional outcome.

CONCLUSION

The ELANA protective bypass is a safe and useful instrument for the treatment of these difficult aneurysms.

Minimally occlusive laser vascular anastomosis (MOLVA): experimental study

BACKGROUND

Temporary occlusion of an intracranial artery during microvascular anastomosis is a major risk factor in cerebrovascular surgery. A new laser vascular welding technique that minimizes the occlusion time of the recipient vessel has been developed and is described in this report.

METHOD

A new minimally occlusive technique of end-to-side microvascular anastomosis was developed employing a diode laser in association with the application of a chromophore in our experimental model of double end-to-side anastomosis. The implantation of a vein graft on the patent carotid artery was obtained through the application of three interrupted sutures at each anastomotic site; the carotid was then clamped, two arteriotomies were performed, followed by the application of a fourth suture and of the laser welding procedure on each anastomosis. Monitoring of the temperature at the site of the anastomosis was introduced in order to control the welding technique.

FINDINGS

The time of the clamping of the carotid artery was 12 min to perform two end-to-side anastomoses (i.e., 6 min for each anastomosis). All bypasses were patent after a follow-up of 90 days and histological study confirmed good preservation of the vascular wall.

CONCLUSIONS

Our laser-assisted technique of vascular anastomosis reduces the duration of the clamping of the recipient artery down to 6 min. This technique can minimize the risk of cerebral ischemia associated with occlusion of a recipient artery in intracranial bypass procedures, promoting an improved vascular healing process with a lower risk of thrombosis and occlusion.

TREATMENT OF GIANT MIDDLE CEREBRAL ARTERY ANEURYSMS WITH A FLOW REPLACEMENT BYPASS USING THE EXCIMER LASER-ASSISTED NONOCCLUSIVE ANASTOMOSIS TECHNIQUE

OBJECTIVE

To define the clinical value of the flow replacement bypass using the excimer laser-assisted nonocclusive anastomosis (ELANA) technique in the treatment of patients with a noncoilable, nonclippable giant intracranial aneurysm of the middle cerebral artery (MCA).

METHODS

Between 1999 and 2006, 22 patients with a giant intracranial aneurysm of the MCA were treated in our hospital with an ELANA flow replacement bypass and MCA occlusion. We collected data on patient characteristics, operative aspects, complications, and functional health scores using the modified Rankin Scale. Mean follow-up was 3.6 years (range, 0.2–7.7 yr).

RESULTS

We were able to construct a patent bypass in 20 (91%) of 22 patients. All 34 ELANA attempts resulted in a patent anastomosis with a strong backflow directly after ELANA catheter retraction. The patients did not need to undergo temporary occlusion in any of the ELANA constructions. Mean ± standard deviation intracranial-to-intracranial bypass flow was 53 ± 13 ml/min. MCA aneurysm treatment was attempted in all 20 patients who had a patent bypass and was successful in 19 of them. There was a fatal hemorrhagic complication in one patient (5%), a nonfatal hemorrhagic complication in three patients (14%), and a nonfatal ischemic complication in six patients (27%). At follow-up, 17 patients (77%) had a functionally favorable outcome (modified Rankin Scale score at follow-up was the same as or less than the preoperative modified Rankin Scale score). All of these patients were independent at follow-up (modified Rankin Scale score ≤2).

CONCLUSION

This study demonstrates satisfactory results in the treatment of giant MCA aneurysms with an ELANA flow replacement bypass, considering the very grave natural history and treatment complexity of these lesions. The ELANA technique is a useful tool in the treatment armamentarium of the vascular neurosurgeon.

Revascularization for complex intracranial aneurysms

The modern management of intracranial aneurysms includes both constructive and deconstructive strategies to eliminate the aneurysm from the circulation. Both microsurgical and endovascular techniques are used to achieve this goal. Although most aneurysms can be eliminated from the circulation with simple clip reconstruction and/or coil insertion, some require revascularization techniques to enhance tolerance of temporary arterial occlusion during clipping of the aneurysm neck or to enable proximal occlusion or trapping. In fact, the importance of revascularization techniques has grown because of the need for complex reconstructions when endovascular therapies fail. Moreover, the safety and feasibility of bypass have progressed due to advances in neuroanesthesia, technological innovations, and ~ 5 decades of accumulating wisdom by bypass practitioners. Cerebral revascularization strategies become necessary in select patients who possess challenging vascular aneurysms due to size, shape, location, intramural thrombus, atherosclerotic plaques, aneurysm type (for example, dissecting aneurysms), vessels arising from the dome, or poor collateral vascularization when parent artery or branch occlusion is required. These techniques are used to prevent cerebral ischemia and subsequent clinical sequelae. Bypass techniques should be considered in cases in which balloon test occlusion demonstrates inadequate cerebral blood flow and in which there is a need for Hunterian ligation, trapping, or prolonged temporary occlusion. This review article will focus on decision making in bypass surgery for complex aneurysms. Specifically, the authors will review graft options, the utility of balloon test occlusion in decision making, and bypass strategies for various aneurysm types.

Excimer laser–assisted nonocclusive anastomosis

Excimer laser–assisted nonocclusive anastomosis (ELANA) has been developed over the past 14 years for assistance in the creation of intracranial bypasses. The ELANA technique allows the creation of intracranial–intracranial and extracranial–intracranial bypasses without the need for temporary occlusion of the recipient artery, avoiding the inherent risk associated with occlusion time. In this review the authors discuss the technique and its indications, while reviewing the clinical results of the procedure. The technique itself is explained using cartoon drawings and intraoperative photographs. Advantages and disadvantages of the technique are also discussed.

Sutureless nonocclusive bypass surgery in combination with an expanded polytetrafluoroethylene graft. Laboratory investigation

OBJECT

Cerebral aneurysms that cannot be treated by clip or coil placement can be treated with high-flow bypass surgery using techniques such as the excimer laser-assisted nonocclusive anastomosis (ELANA). To simplify the technique, a sutureless ELANA (SELANA) was developed in combination with an expanded polytetrafluoroethylene (ePTFE) graft.

METHODS

In 18 rabbits a bypass was constructed on the abdominal aorta using the SELANA technique with an ePTFE graft, resulting in 18 bypasses and 36 anastomoses. Short-term effects were analyzed in the first 2 weeks and at 2 and 3 months after the procedure. Patency was evaluated using quantitative ultrasound flowmetry. The anastomotic sites were studied using scanning electron microscopy.

RESULTS

Construction of the bypass using the SELANA technique was easier and faster (15-25 minutes) compared with bypasses made with the ELANA technique (> 90 minutes). At the end of follow-up, 16 of 18 bypasses were patent. Of 36 SELANA anastomoses, 32 could be completed without short temporary occlusion of the recipient vessel. Scanning electron microscopy showed complete coverage of all anastomoses with neointimal repair tissue after 10 days.

CONCLUSIONS

The SELANA technique provides further advantages over the conventional ELANA technique in ease of use and shortening of procedure time. The patency rate in this series was 89% and neointima repair tissue at the anastomosis site was complete after 10 days. Further experimental studies of the long-term patency and safety of this technique are necessary before clinical application.

Historical landmarks in vascular neurosurgery "On July 10th 2006, at the 70th Anniversary of the Department of Neurosurgery of Zürich Medical School"

Direct aneurysm surgery started more than 70 years ago. Introduction of cerebral angiography by Moniz in 20s and operating microscope by Yaşargil in 60s were the real cornerstones in vascular neurosurgery. Since then the development of neuroanestesiology and further development of non-invasive imaging (MRA and CTA) together with the latest development of operating microscopes with intraoperative ICG angio have shifted vascular microneurosurgery to a different level to still compete with the 'non-invasiness' of endovascular therapy. There is an increasing demand to perform the already forgotten bypasses mastered only by few and with the high-flow techniques (e.g. ELANA) we can treat lesions that some time ago were considered impossible. Endovascular embolization to reduce the flow in AVM before surgery is very helpful in those cases that can not be treated by embolization or radiosurgery alone. We still need to find a way to detect aneurysms before they rupture and especially those thin-walled that are in an increased risk of rupture. Recent data on the pathobiology of the aneurysm wall may help us to better understanding of the growth mechanisms and it might be possible to develop more potent local or systemic pharmaceutical therapy to induce myo-intimal hyperplasia occluding the aneurysm and strengthening the wall to prevent rupture.

Extracranial-intracranial bypass for the treatment of cavernous sinus aneurysms

The optimal management of symptomatic cavernous sinus aneurysms remains controversial. Carotid occlusion is a simple procedure, but carries an ongoing risk of early and late stroke. Cerebral revascularisation is technically demanding and carries a risk of morbidity and mortality of around 10%. Eight patients treated with an extracranial-intracranial vascular bypass graft over a period of 44 months for symptomatic cavernous sinus aneurysms are reviewed. At a mean follow-up of 20 months, seven patients (87.5%) had an excellent outcome (Glasgow Outcome Score 5) while one patient suffered a perioperative stroke. In only one case, where the radial artery had been used, the graft became occluded. The results of this series seem to indicate that cerebral revascularisation is an effective treatment for patients with symptomatic cavernous sinus aneurysms.

Expanded polytetrafluoroethylene graft for bypass surgery using the excimer laser–assisted nonocclusive anastomosis technique

Object

Patients with complex craniocerebral pathophysiologies such as giant cerebral aneurysms, skull base tumors, and/or carotid artery occlusive disease are candidates for a revascularization procedure to augment or preserve cerebral blood flow. However, the brain is susceptible to ischemia, and therefore the excimer laser–assisted nonocclusive anastomosis (ELANA) technique has been developed to overcome temporary occlusion. Harvesting autologous vessels of reasonable quality, which is necessary for this technique, may at times be problematic or impossible due to the underlying systemic vascular disease. The use of artificial vessels is therefore an alternative graft for revascularization. Note, however, that it is unknown to what degree these grafts are subject to occlusion using the ELANA anastomosis technique. Therefore, the authors studied the ELANA technique in combination with an expanded polytetrafluoroethylene (ePTFE) graft.

Methods

The experimental surgeries involved bypassing the abdominal aorta in the rabbit. Ten rabbits were subjected to operations representing 20 ePTFE graft–ELANA end-to-side anastomoses. Intraoperative blood flow, follow-up angiograms, and long-term histological characteristics were assessed 75, 125, and 180 days postoperatively. Angiography results proved long-term patency of ePTFE grafts in all animals at all time points studied. Data from the histological analysis showed minimal intimal reaction at the anastomosis site up to 180 days postoperatively. Endothelialization of the ePTFE graft was progressive over time.

Conclusions

The ELANA technique in combination with the ePTFE graft seems to have favorable attributes for end-to-side anastomoses and may be suitable for bypass procedures.

Revascularizing the upper basilar circulation with saphenous vein grafts: operative technique and lessons learned

BACKGROUND

The purpose of this study was to report our operative technique and lessons learned using saphenous vein conduits to revascularize the rostral basilar circulation (ie, bypass to the posterior cerebral or superior cerebellar arteries). We also review the evolution of this technique for the treatment of vertebrobasilar insufficiency (VBI) and complex posterior fossa aneurysms.

METHODS

Data were collected retrospectively for 8 consecutive patients undergoing rostral basilar circulation saphenous vein bypass grafts at our institution between 1989 and 2004 for the treatment of VBI or in conjunction with Hunterian ligation of complex posterior circulation aneurysms. The indications for treatment, pre- and postoperative neurologic status, angiographic results, operative complications, and long-term clinical outcomes were analyzed for each patient.

RESULTS

With clinical and angiographic follow-up ranging from 3 months to 15 years, 7 of 8 bypasses remained patent, 3 of 3 aneurysms remained obliterated, and 4 of 5 patients with VBI experienced resolution of their preoperative symptoms. There were no surgery-related deaths, but 2 patients did experience major neurologic morbidity. The outcomes for the 217 total patients reported in the literature were as follows: 135 excellent (62%), 26 good (12%), 30 poor (14%), and 26 dead (12%).

CONCLUSIONS

Despite the risk of serious neurologic complications with this procedure, when one considers the natural history of untreated patients, saphenous vein revascularization of the rostral basilar circulation remains an acceptable option. Although surgical technique has varied, patient selection criteria, graft patency, and patient outcomes have been relatively constant over the past 25 years.

ELANA: Excimer Laser-Assisted Nonocclusive Anastomosis for extracranial-to-intracranial and intracranial-to-intracranial bypass: a review

ELANA, excimer laser-assisted nonocclusive anastomosis, is a technique using an excimer laser/catheter system for intracranial bypass surgery of the brain. The technique has been developed over the past 12 years by Tulleken and colleagues at UMC Utrecht in The Netherlands for treatment of primarily untreatable giant aneurysms. We review here the emergence of transplanted conduit bypass as a valuable technique for managing these lesions and the subsequent development of ELANA bypass. The ELANA technique allows the operating surgeon to perform an extracranial-to-intracranial or intracranial-to-intracranial bypass using a transplanted large caliber conduit without occlusion of the recipient artery, thus eliminating intraoperative ischemic insult related to temporary occlusion time. We describe the ELANA technique, illustrate it with intraoperative photos, and review the relevant literature. ELANA is shown to be safe; we discuss its advantages over conventional techniques.

Long-term reendothelialization of excimer laser—assisted nonocclusive anastomoses compared with conventionally sutured anastomoses in pigs

Object. In contrast to conventional anastomosis methods, the excimer laser—assisted nonocclusive anastomosis (ELANA) technique involves a platinum ring and intima—adventitia apposition with a rim of medial and adventitial layers exposed to the bloodstream. The authors assessed the reendothelialization of porcine carotid arteries through ELANA compared with conventional anastomosis by using scanning electron microscopy.

Methods. In 28 pigs a bypass with one ELANA and one conventional anastomosis was made on the left common carotid artery. All patent anastomoses were evaluated intraoperatively with the aid of an ultrasonographic flowmeter and postoperatively by using scanning electron microscopy at 2 weeks, 2 months, 3 months, and 6 months thereafter. Twenty-four of 28 bypasses (48 of 56 end-to-side anastomoses) were fully patent at the time of evaluation. On scanning electron microscopic evaluation of the bypasses, all 48 patent anastomoses showed complete reendothelialization, including all 24 ELANAs in which the endothelium covered the rim and the laser-ablated edge completely. No endothelial difference was observed between conventional anastomoses and ELANAs, aside from the obvious anatomical differences like the platinum ring, which had been completely covered with endothelium. At 6 months postsurgery, remodeling of the ELANA was observed, leaving the ring covered with a layer of endothelium as the most narrow part of the anastomosis.

Conclusions. In long-term experiments, ELANA allows reendothelialization comparable to that achieved with conventional anastomosis. Considering its nonocclusive and high-flow characteristics, the ELANA technique is preferable in cerebral revascularization procedures.

Microsurgical anatomy of cerebral revascularization. Part II: Posterior circulation

Object. Revascularization is an important component of treatment for complex aneurysms, skull base tumors, and vertebrobasilar ischemia in the posterior circulation. In this study, the authors examined the microsurgical anatomy related to cerebral revascularization in the posterior circulation and demonstrate various procedures for bypass surgery.

Methods. The microsurgical anatomy of cerebral and cerebellar vessels as they relate to revascularization procedure and techniques, including extracranial-to-intracranial bypass grafting, arterial interposition grafting, and side-to-side anastomosis, were examined by performing stepwise dissections in 22 adult cadaveric specimens. The arteries and veins in the specimens were perfused with colored silicone.

Dominant cerebral and cerebellar revascularization procedures in the posterior circulations include superficial temporal artery (STA)—posterior cerebral artery (PCA), STA—superior cerebellar artery (SCA), occipital artery (OA)—anterior inferior cerebellar artery, OA—posterior inferior cerebellar artery (PICA), and PICA—PICA anastomoses. These procedures are effective in relatively small but critical areas including the brainstem and cerebellum. For revascularization of larger areas a saphenous vein graft is used to create a bypass between the PCA and the external carotid artery. Surgical procedures are generally difficult to perform in deep and narrow operative spaces near critical vital structures.

Conclusions. Although a clear guideline for cerebral revascularization procedures has not yet been established, it is important to understand various microsurgical techniques and their related anatomical structures. This will help surgeons consider surgical indications for treatment of patients with vertebrobasilar ischemia caused by aneurysms, tumors, or atherosclerotic diseases in the posterior circulation.

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.

Treatment and outcome in 30 patients with posterior cerebral artery aneurysms

OBJECT

The records of 30 patients with posterior cerebral artery (PCA) aneurysms treated during a 12-year period were reviewed to determine outcome and the risk of visual field deficit associated with PCA sacrifice.

METHODS

Clinical data and treatment summaries for all patients were maintained in an electronic database. The Glasgow Outcome Scale (GOS) and modified Rankin Scale (mRS) scores were determined by an independent registrar. Visual field changes were determined by review of medical records. Twenty-eight patients were treated with open surgery, one of them after an attempt at detachable coil embolization failed. Two patients underwent successful endovascular PCA sacrifice. The mean GOS and mRS scores in 18 patients with unruptured aneurysms were 4 and 2, respectively, at discharge. Subarachnoid hemorrhage (SAH) from other aneurysms and neurological deficits caused by the PCA lesion or underlying disease contributed to poor outcomes in this group. The mean GOS and mRS scores in 12 patients with ruptured aneurysms were 4 and 4, respectively, at discharge. One patient died of severe vasospasm. Neurological deficits secondary to SAH and, in one patient, treatment of a concomitant arteriovenous malformation contributed to poor outcomes in the patients with ruptured aneurysms. Seven patients with normal visual function preoperatively underwent PCA occlusion. One patient (14%) developed a new visual field deficit.

CONCLUSIONS

Optimal treatment of PCA aneurysms is performed via one of several surgical approaches or by endovascular therapy. The approach is determined, in part, by the anatomical location and size of the aneurysm and the presence of underlying disease and neurological deficits.

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.

Construction of a new posterior communicating artery in a patient with poor posterior fossa circulation: technical case report

OBJECTIVE AND IMPORTANCE

The carotid and the vertebrobasilar circulation were connected, effectively creating a new posterior communicating artery (PComA). The excimer laser-assisted nonocclusive anastomosis technique is a new anastomosis technique whereby formerly untreatable patients may be treated with an intracranial artery-to-intracranial artery bypass procedure. This report is the first one in which an angiographically proved patent internal carotid artery-posterior cerebral artery segment P1 bypass is presented.

CLINICAL PRESENTATION

Our patient presented with repeated episodes of vertebrobasilar ischemia because of vertebral artery occlusion and stenosis.

INTERVENTION

An internal carotid artery-posterior cerebral artery segment P1 bypass procedure was performed. Because the patient experienced transient ischemia in the left cerebral hemisphere at the end of postoperative angiography procedure, no radiological intervention was performed, and the patient refused to undergo a new radiological intervention at a later stage.

TECHNIQUES

Both anastomoses were made using the excimer laser-assisted nonocclusive anastomosis technique.

CONCLUSION

Intraoperative flowmetry was performed using an ultrasound flowmeter, which disclosed blood flow of 35 ml/min through the bypass. We hope that this new PComA suffices to protect the patient from infarction in the territory of the vertebrobasilar circulation.