First clinical experience with excimer assisted high flow bypass surgery of the brain

Summary A new type of revascularization of the brain is used in patients with brain ischaemia, caused by an occlusion of one or both internal carotid arteries, and in patients in whom the internal carotid artery has been deliberately occluded for the treatment of a giant aneurysm of the internal carotid artery.A so-called high flow extra-intracranial bypass operation is performed. An arterial or venous transplant is interposed between a branch of the external carotid artery or the external carotid artery itself and the intracranial portion of the internal carotid artery. The anastomosis with the intracranial portion of the internal carotid artery is made without temporary occlusion of the recipient artery and with the aid of the newly developed Excimer laser assisted anastomosis technique.The results of animal experiments and of a clinical series of 9 patients are reported.     

Experimental laser-assisted end-to-side microvascular anastomosis

The authors present a new technique of end-to-side microvascular anastomosis in a rat carotid artery model, employing a milliwatt CO2 laser. Both carotid arteries were isolated and approximated in an end-to-side fashion by the placement of four 10-0 nylon stay sutures. The milliwatt CO2 laser was used to effect vessel anastomosis between the sutures, using 70-100 mW of power. Animals were killed 8 weeks postoperatively. Angiography of each anastomosis was performed in all animals. All anastomoses were then harvested, and submitted for histological analysis. Anastomotic patency was 100%, both intraoperatively and angiographically. There was no evidence of intravascular thrombus, anastomotic stenosis, or pseudoaneurysm formation. Early in the experiment, some anastomoses showed localized dilatation at the anastomotic site. The histologic changes at the anastomotic site are described. Laser-assisted microvascular anastomosis is a feasible technique, and a potential alternative to conventional suture techniques.     

Towards sutureless non-occlusive cerebral revascularization

Sutureless vascular anastomoses have been the subject of extensive research for decades. In neurosurgery the need for a safe and fast technique is high, because temporary occlusion of cerebral arteries may rapidly lead to brain ischemia. Conventional sutured anastomoses have always been the golden standard. Limited working space and difficult suturing techniques were reasons to find alternatives. Many artificial devices to create anastomoses have been engineered over the years like tissue sealants, clips and automated suturing sets with variable success. For all previous options, temporary occlusion of the recipient artery was necessary. The Excimer Laser Assisted Non-Occlusive Anastomosis (ELANA) technique? facilitates the construction of an end-to-side anastomosis without temporary occlusion of the recipient artery using a platinum ring and a laser. However, the technical challenge of intracranial micro-sutures remained. Experiments using less sutures eventually resulted in a sutureless ELANA (SELANA) anastomosis. After in vitro and in vivo experiments, the SELANA slide was considered feasible for intracranial use although some concrete improvements, like the inclusion of a clip at the back of the device, were needed. Therefore, the development of an ideal sutureless anastomosis is still ongoing. This process is an evolution rather than a revolution.     

End-to-side anastomosis of rat carotid artery: comparison of different types of section and shape of the terminal end

Summary In 50 rats, different types of end-to-side carotid artery anastomoses were compared. In one technique, a longitudinal split in the long axis of the vessel was performed to enhance the diameter of the anastomosis. This theoretical advantage was not confirmed in this series. The clamping time, anastomoses time, and tamponade time were increased significantly when compared with a simple, slightly oblique end-to-side anastomosis. This study highlighted that the most simple type of end-to-side anastomosis gave less bleeding, achieved a quicker water-tight anastomosis and decreased the risk of late problems.     

End-to-side microvascular anastomosis using an external metal ring.

Enthusiasm for developing safer and faster anastomotic techniques and complementary devices continues. We report on a new microvascular end-to-side anastomosis technique using a silver ring around the anastomotic circumference. The purpose of this study was to compare the effectiveness of this technique with conventional end-to-side vessel anastomosis.Forty Sprague-Dawley rats were divided into two groups. Twenty rats were used to assess the external ring method in end-to-side anastomosis between carotid arteries and anterior jugular veins and the remaining 20 formed the control group with conventional end-to-end anastomosis.The anastomosis time was 26.4 min for standard suture anastomosis and 18.4 min for the external ring technique (P< 0.01). Patency was 95% with standard technique and 100% using the external ring (P> 0.05). The external ring technique of end-to-side microvascular anastomosis is a safe and reliable method and may reduce the operation time. Its clinical applicability should be further evaluated.     

Mattress anastomosis in micro vascular reconstruction: technical note

Background

Superficial temporal artery-to-middle cerebral artery (STA-MCA) anastomosis is a common procedure for neurosurgeons. The surgery necessarily requires accurate and speedy manipulation of microscope, for which a specific training is needed. Unexpected bypass occlusion sometimes happen during surgery.

Objective

Generally, conventional interrupted or continuous suture has been used for vascular anastomosis, despite various ideas have been attempted in the other surgery fields. We propose a horizontal mattress suture technique for intracranial microvascular bypass surgery. This is the first report ever published on intracranial vascular anastomosis.

Methods

We had four patients of STA-MCA bypass surgery with “mattress anastomosis” from March to May of 2012.

Results

During the procedure, there was no bypass occlusion and good patency was confirmed in all cases.

Conclusion

Intimae of the recipient and the donor blood vessel contact each other precisely with this technique. Although a long-term assessment of patency is needed, it is useful for the intracranial bypass surgery.     

Automated, compliant, high-flow common carotid to middle cerebral artery bypass

The authors describe the use of the Cardica C-Port xA Distal Anastomosis System to perform an automated, high-flow extracranial-intracranial bypass. The C-Port system has been developed and tested in coronary artery bypass surgery for rapid distal coronary artery anastomoses. Air-powered, it performs an automated end-to-side anastomosis within seconds by nearly simultaneously making an arteriotomy and inserting 13 microclips into the graft and recipient vessel. Intracranial use of the device was first simulated in a cadaver prepared for microsurgical anatomical dissection. The authors used this system in a 43-year-old man who sustained a subarachnoid hemorrhage after being assaulted and was found to have a traumatic pseudoaneurysm of the proximal intracranial internal carotid artery. The aneurysm appeared to be enlarging on serial imaging studies and it was anticipated that a bypass would probably be needed to treat the lesion. An end-to-side bypass was performed with the C-Port system using a saphenous vein conduit extending from the common carotid artery to the middle cerebral artery. The bypass was demonstrated to be patent on intraoperative and postoperative arteriography. The patient had a temporary hyperperfusion syndrome and subsequently made a good neurological recovery. The C-Port system facilitates the performance of a high-flow extracranial-intracranial bypass with short periods of temporary arterial occlusion. Because of the size and configuration of the device, its use is not feasible in all anatomical situations that require a high-flow bypass; however it is a useful addition to the armamentarium of the neurovascular surgeon.     

Apprentissage des techniques microchirurgicales vasculaires sur un modèle animal

IntroductionThe aim of this study was to assess the progress of an operator, during microsurgical training, on a bilateral carotid revascularization in the rat.Material and methodsIn this prospective study, nine rats underwent bilateral carotid revascularization. An end-to-end graft of the right carotid artery by the facial vein and an end-to-side bypass of left carotid artery by the jugular external vein were performed. Anastomoses were carried out with 10/0 thread, based on the technique of the symmetric bi-angulation. At the end of procedure, a permeability test was performed on each anastomosis. Duration of survival of the animal, permeability of anastomosis, and evolution of the operating periods during the training were collected and respectively analyzed with a Fisher's and Student's t tests. In cases of procedure success, anastomoses were remotely controlled and a brain dissection was performed in order to seek a possible ischemia due to carotid clamping. In the event of failure, the rat was sacrificed and anastomoses were opened in order to establish the cause of thrombosis.ResultsTwo thirds of the revascularization procedures were successful. A total of 83.3% of the anastomoses were patent. Of the six rats preserved for remote evaluation of anastomoses, three died. Remotely controlled anastomoses remained all permeable. No cerebral ischemia, associated with carotid clamping (approximately 45 minutes), was highlighted by brain dissection. With the growing experience of the operator, an improvement in results in mastery of the technique was objectively observed. Operative durations were reduced between the beginning and the end of the training: −54 minutes (P = 0.001).ConclusionMicrosurgical laboratory training seems to be essential in order to acquire the dexterity, ease and experience necessary for performing microsurgical procedures in humans.     

New type of end-to-side anastomosis for small arteries: a technical and scanning electron microscopic study in rats

A new type of end-to-side anastomosis between small arteries is described. The anastomosis is made for three-quarters of its circumference with a nonoccluded recipient artery. The recipient artery must be occluded for only 3 to 5 minutes to complete the anastomosis. The anastomosis site was studied with the scanning electron microscope at different times (1 hour to 3 months) after the operation in 20 rats. In every case, the anastomosis was widely patent and a gradual endothelialization of the anastomosis site was observed. After 7 to 10 days, the endothelialization was more or less complete and, during the following weeks, a further smoothing of the ridge protruding into the anastomosis was noted. As an addendum, the authors describe an improvement of this technique that was developed after the sapphire tip of the neodymium: YAG laser became available. Now the anastomosis is fully completed and the connection between the two vessels is made by the laser tip introduced via a side branch of the donor vessel. The recipient artery need not be occluded at all. The results are promising.     

Vascular anastomoses in free jejunal reconstruction to the neck vessels: an experience of consecutive 20 cases without using surgical microscope

Twenty consecutive cases of pharyngoesophageal cancer who underwent free jejunal reconstruction were reported. The common carotid or external carotid artery was used for a feeder of the free graft. The internal jugular vein were served as a drainage vein. All anastomoses were performed in an end-to-side fashion without using surgical microscopes. Mean carotid artery clamping time was 16 minutes and no neurological complications were noticed postoperatively. Graft failure was occurred in 1 patient. The presenting technique, showing 95% success rate, is recommended as a simple option for vascular anastomosis in free jejunal reconstructive surgery.     

Availability of end-to-side arterial anastomosis to the external carotid artery using short-thread double-needle microsuture in free-flap transfer for head and neck reconstruction

We seldom have difficulties in the selection of appropriate recipient arteries for microvascular free flap transfer in the head and neck region because many sizable branches (branch artery) of the external carotid artery (ECA) or subclavian artery are available. However, we occasionally encountered the lack of an appropriate recipient artery, especially in secondary reconstruction or reconstruction following the extensive ablation of recurrent cancer. For these challenging cases, we have used end-to-side arterial anastomosis directly to the ECA. Between July 1997 and December 2004, end-to-side anastomosis of the flap artery to the ECA was employed in 16 cases. The reason for its use included the marked size discrepancy between the jejunal artery and branch artery in 4 jejunal transfer cases, the lack of 2 appropriate recipient arteries for double free flap transfers in 1 case, and the lack of an available branch artery as a recipient due to poor regional conditions in 11 cases. Fifteen of 16 flaps underwent an uneventful postoperative course, except 1 whose flap artery was pressed by the submandibular gland and sustained thrombosis 3 days postoperatively. In this case, however, the flap survived perfectly after prompt thrombectomy and reanastomosis. Eventually, all 16 flaps survived completely. We reconfirmed the availability of end-to-side anastomosis to the ECA when a suitable branch artery is not available. Although end-to-side anastomosis to the ECA is laborious compared with end-to-end anastomosis, our newly developed short-thread double-needle microsuture combined with the back-wall-first technique helps to ensure easier anastomosis. Using this device, because all stitches are carried from inside the vessel to outside, the surgeon can place the first stitch at any point on the posterior wall and advance the next suture to the preferred site of the previous suture, and suturing can be performed more safely even in cases where the tunica intima is separated from the tunica media due to arteriosclerosis, previous irradiation, or surgery.     

The precise technique of end-to-side microvascular anastomosis with a suitable experimental model.

In order to perform extracranial to intracranial microrevascularisation a good end-to-side microvascular anastomosis technique is the first essential. The rabbit femoral vessels are similar in size to the human cortical branches of the middle meningeal artery and superficial temporal artery and an easy technique of end-to-side anastomosis of these vessels is described. This pays particular attention to proof of patency until the last stitch is applied. Assessment of patency in all three directions is checked by the directional Doppler or the electromagnetic flow probe.     

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.     

The ELANA technique: Constructing a high flow bypass using a non-occlusive anastomosis on the ICA and a conventional anastomosis on the SCA in the treatment of a fusiform giant basilar trunk aneurysm

Summary A patient with a partially thrombosed fusiform giant basilar trunk aneurysm presented with devastating headache and symptoms of progressive brain stem compression. Having an aneurysm inaccessible for endovascular treatment, and after failing a vertebral artery balloon occlusion test, he was offered bypass surgery in order to exclude the aneurysm from the cerebral circulation and relieve his symptoms. A connection between the intracranial internal carotid artery and the superior cerebellar artery was created whereupon the basilar artery was ligated just distally to the aneurysm. The proximal anastomosis on the internal carotid artery was made using the excimer laser-assisted non-occlusive anastomosis (ELANA) technique, while a conventional end-to-side anastomosis was used for the distal anastomosis on the superior cerebellar artery. Intra-operative flowmetry showed a flow through the bypass of 40ml/min after ligation of the basilar artery. An angiogram 24 hours later showed normal filling of the bypass and the vessels supplied by it, but also disclosed a subtotal occlusion of the proximal ipsilateral middle cerebral artery with delayed filling distally. The patient, who had a known thrombogenic coagulopathy, died the following day. Autopsy showed no signs of ischemia in the territories supplied by the bypass, but a thrombus in the proximal middle cerebral artery and massive acute hemorrhagic infarction with swelling in its territory and uncal herniation. Multiple fresh thrombi were found in the lungs. The ELANA anastomosis showed re-endothelialisation without thrombus formation on the inside.     

End-to-side anastomosis of small vessels using an Nd:YAG laser with a hemispherical contact probe. Technical note.

A new technique is described which enables the surgeon to perform an end-to-side anastomosis between arteries with little (less than 2 minutes) or no occlusion of the recipient artery. The technique was developed in rabbits, but has recently been successfully used in a patient in whom an anastomosis between the superficial temporal artery and a proximal branch of the middle cerebral artery was created.     

End-to-side and end-to-end vascular anastomoses with a carbon dioxide laser

This study was designed to compare anastomoses performed with a carbon dioxide laser and conventional anastomoses performed with 7-0 polypropylene suture. In each of 80 rabbits, the divided left carotid artery was anastomosed by a continuous suture technique and the right carotid was anastomosed with a carbon dioxide laser. In each of 40 additional rabbits, both end-to-end and end-to-side laser anastomoses were performed on the same carotid artery. The laser technique involved the placement of three stay sutures (end-to-end technique) or four stay sutures (end-to-side technique) of 7-0 polypropylene and an everting laser seal at a power level of 65 mW. The 1-year overall patency rate was 98% (78/80) in laser anastomoses, 79% (63/80) in suture anastomoses, and 95% (38/40) in combined end-to-end and end-to-side laser anastomoses. Microscopic findings in laser anastomoses demonstrated degeneration of collagen and protein in the adventitia and media, but much less intimal injury than in suture anastomoses, with reendothelialization beginning earlier (within 7 days after anastomosis as compared with 2 to 4 weeks). The tissue tensile strength at 1 hour was less in laser anastomoses than in suture anastomoses, but the laser anastomoses still withstood an intraluminal pressure load of 380 mm Hg. Laser anastomosis improved the microscopic and histologic appearance of the intimal layer, allowing for rapid early reendothelialization and resulting in excellent patency rates.     

Superficial Temporal Artery to Middle Cerebral Artery Bypass

The superficial temporal artery to middle artery bypass is a technique that allows the blood supply from the extracranial carotid circulation to be routed to the distal middle cerebral artery branches. The procedure allows blood flow to bypass proximal lesions of the intracranial vasculature. The performance of this bypass requires specialized microvascular training and the use of microvascular techniques. The techniques involved in performing these procedures include microdissection of the superficial temporal artery in the scalp, microdissection of the recipient middle cerebral artery branches near the sylvian fissure, and anastomosis techniques using either microvascular sutures or a microanastomotic device. The successful completion of the bypass and subsequent patency requires meticulous attention to technical details.     

Effect of extracranial-intracranial vascular bypass formation on experimental cerebral infarction in dogs (author's transl)

The middle cerebral artery was occluded at its origin via subtemporal approach by microsurgical technique in 24 dogs. In 8 of these 24 dogs, end-to-side anastomosis between the maxillary artery and a branch of the middle cerebral artery (MA-MCA anastomosis) was made 4 hours after MCA occlusion. In 5 dogs, MA-MCA anastomosis was performed under microscopic control 3 weeks after MCA occlusion. Remaining 11 dogs without shunt operation were used as control animals. All the animals were clinically observed every day until sacrifice. In the control animals, common carotid angiography was performed between the 2nd and the 5th postoperative weeks. The treated animals were studied by selective external carotid angiography 2 weeks after MA-MCA anastomosis. After sacrifice, transcarotid perfusion with 10% formalin solution was carried out and the brain was carefully removed. Each brain was additionally fixed in 10% formalin, sectioned, stained and examined pathologically. Clinical evaluation in all the control animals showed mild to severe neurological deficits or death. On the other hand, the animals with patent bypass in acute stage demonstrated no neurological deficits. Gross and microscopic evaluation of the brains showed that the permanent occlusion produced a medium or large-sized infarct in the occluded MCA territory, and the patent prompt bypass usually caused no or only microscopic infarct. In the patent delayed bypass, the size of infarct seemed smaller than that in the untreated animals. No hemorrhagic infarct was found in treated animals with either prompt or delayed bypass. In general, it seemed that the animals with patent bypass fared better than untreated animals both clinically and pathologically. The experimental data suggest that reestablishment of blood flow by extra-intracranial anastomosis, particularly within 4 hours after MCA occlusion, may lead to a significant restoration of neurological function without pathological damage of the brain.     

Cylindrical or T-shaped silicone rubber stents for microanastomosis--technical note

The ostium of the recipient artery and the orifice of the donor artery must be clearly visualized for the establishment of microvascular anastomosis. Specially designed colored flexible cylindrical or T-shaped silicone rubber stents were made in various sizes (400 or 500 microns diameter and 5 mm length) and applied to bypass surgery in patients with occlusive cerebrovascular disease such as moyamoya disease and internal carotid artery occlusion. The colored flexible stents facilitated confirmation of the ostium of the artery even in patients with moyamoya disease and allowed precise microvascular anastomosis without problems caused by the stent.     

One patent intracranial collateral predicts tolerance of flow reversal during carotid angioplasty and stenting

Internal carotid artery (ICA) flow reversal is an effective means of cerebral protection during carotid stenting. Its main limitation is that in the absence of adequate collateral flow it may not be tolerated by the patient. The purpose of this study was to determine if preoperative identification of intracranial collaterals with computerized tomographic (CTA) or magnetic resonance (MRA) angiography can predict adequate collateral flow and neurological tolerance of ICA flow reversal for embolic protection. This was a study of patients undergoing transcervical carotid angioplasty and stenting. Neuroprotection was established by ICA flow reversal. All patients underwent preoperative cervical and cerebral noninvasive angiography with CTA or MRA and had at least one patent intracranial collateral. Mean carotid artery back pressure was measured. Neurological changes during carotid clamping and flow reversal were continuously monitored with electroencephalography (EEG). Thirty-seven patients with at least one patent intracranial collateral on brain imaging with CTA or MRA were included. Mean carotid artery back pressure was 58 mm Hg. All procedures were technically successful. No EEG changes were present with common carotid artery occlusion and ICA flow reversal. One patent intracranial collateral provides sufficient cerebral perfusion to perform carotid occlusion and flow reversal with absence of EEG changes. Continued progress in noninvasive imaging modalities is becoming increasingly helpful in our understanding of cerebral physiology and selection of patients for invasive carotid procedures.