Vascular reconstruction using interposed small vessels

Internal Maxillary Artery to Anterior Circulation Bypass with Local Interposition Grafts Using a Minimally Invasive Approach: Surgical Anatomy and Technical Feasibility

BACKGROUND

The internal maxillary artery (IMA) is a reliable donor for extracranial-intracranial high-flow bypasses. However, previously described landmarks and techniques to harvest the IMA are complex and confusing and require extensive bone drilling, carrying significant neurovascular risk. The objective of our study was to describe a minimally invasive technique for exposing the IMA and to assess the feasibility of using the IMA as a donor for anterior-circulation recipient vessels using 2 different local interposition vessels.

METHODS

Via a minimally invasive technique, the IMA was harvested in 10 cadaveric specimens and a pterional craniotomy was performed. Two interposition grafts-the superficial temporal artery (STA) and middle temporal artery-were evaluated individually. Transsylvian exposure of the second segment of middle cerebral artery (M2), the supraclinoid internal carotid artery, and the proximal postcommunicating anterior cerebral artery segment was completed. Relevant vessel calibers and graft lengths were measured for each bypass model.

RESULTS

The mean caliber of the IMA was 2.7 ± 0.5 mm. Of all 3 recipients, the shortest graft length was seen in the IMA-STA-M2 bypass, measuring 42.0 ± 8.4 mm. There was a good caliber match between the M2 (2.4 ± 0.4 mm) and STA (2.3 ± 0.4 mm) at the anastomotic site. The harvested middle temporal artery was sufficient in length in only 30% cases, with a mean distal caliber of 2.0 ± 0.7 mm.

CONCLUSIONS

This study confirmed the technical feasibility of IMA as a donor for an extracranial-intracranial bypass to the second segment of the anterior cerebral artery, M2, and the supraclinoid internal carotid artery. However, IMA-STA-M2 was observed to be the most suitable bypass model.

Risk factors for neurological worsening and symptomatic watershed infarction in internal carotid artery aneurysm treated by extracranial-intracranial bypass using radial artery graft

OBJECT

The revascularization technique, including bypass created using the external carotid artery (ECA), radial artery (RA), and M2 portion of middle cerebral artery (MCA), has remained indispensable for treatment of complex aneurysms. To date, it remains unknown whether diameters of the RA, superficial temporal artery (STA), and C2 portion of the internal carotid artery (ICA) and intraoperative MCA blood pressure have influences on the outcome and the symptomatic watershed infarction (WI). The aim of the present study was to evaluate the factors for the symptomatic WI and neurological worsening in patients treated by ECA-RA-M2 bypass for complex ICA aneurysm with therapeutic ICA occlusion.

METHODS

The authors measured the sizes of vessels (RA, C2, M2, and STA) and intraoperative MCA blood pressure (initial, after ICA occlusion, and after releasing the RA graft bypass) in 37 patients. Symptomatic WI was defined as presence of the following: postoperative new neurological deficits, WI on postoperative diffusion-weighted imaging, and ipsilateral cerebral blood flow reduction on SPECT. Neurological worsening was defined as the increase in 1 or more modified Rankin Scale scores. First, the authors performed receiver operating characteristic curve analysis for continuous variables and the binary end point of the symptomatic WI. The clinical, radiological, and physiological characteristics of patients with and without the symptomatic WI were compared using the log-rank test. Then, the authors compared the variables between patients with and without neurological worsening at discharge and at the 12-month follow-up examination or last hospital visit.

RESULTS

Symptomatic WI was observed in 2 (5.4%) patients. The mean MCA pressure after releasing the RA graft (< 55 mm Hg; p = 0.017), mean (MCA pressure after releasing the RA graft)/(initial MCA pressure) (< 0.70 mm Hg; p = 0.032), and mean cross-sectional area ratio ([RA/C2 diameter]2 < 0.40 mm [p < 0.0001] and [STA/C2 diameter]2 < 0.044 mm [p < 0.0001]) were related to the symptomatic WI. All preoperatively independent patients remained independent (modified Rankin Scale score < 3). After adjusting for age and sex, left operative side (p = 0.0090 and 0.038) and perforating artery ischemia (p = 0.0050 and 0.022) were related to neurological worsening at discharge (11 [29%] patients) and at the 12-month follow-up or last hospital visit (8 [22%] patients).

CONCLUSIONS

Results of the present study showed that the vessel diameter and intraoperative MCA pressure had impacts on the symptomatic WI and that operative side and perforating artery ischemia were related to neurological worsening in patients with complex ICA aneurysms treated by ECA-RA-M2 bypass.

Posttraumatic carotid-cavernous fistulae treated by internal carotid artery trapping and high-flow bypass using a radial artery graft--two case reports

Two patients presented with post-traumatic carotid-cavernous sinus fistulae (CCFs) that were successfully treated by high-flow bypass using a radial artery graft after initial unsuccessful attempts at obliteration by intravascular embolization. Case 1 was a 20-year-old man with a CCF detected by magnetic resonance imaging and angiography following an accident. Although the CCF appeared partially occluded by intravascular embolization, serial angiography revealed CCF recurrence. The CCF was trapped by placing a high-flow bypass. Case 2 was a 21-year-old man who presented with bilateral CCFs after sustaining face trauma. The bilateral CCFs were directly treated because of recurrence after balloon occlusion. At present, intravascular surgery is the first treatment choice, but placing a high-flow bypass with trapping of the CCF gained time to treat the CCF and may be useful for treating post-traumatic CCF that cannot be effectively eliminated by intravascular techniques.

Extracranial-intracranial bypass surgery using a radial artery interposition graft for cerebrovascular diseases

OBJECTIVE

To investigate the efficacy of extracranial-intracranial (EC-IC) bypass surgery using a radial artery interposition graft (RAIG) for surgical management of cerebrovascular diseases.

METHODS

The study involved a retrospective analysis of 13 patients who underwent EC-IC bypass surgery using RAIG at a single neurosurgical institute between 2003 and 2009. The diseases comprised intracranial aneurysm (n=10), carotid artery occlusive disease (n=2), and delayed stenosis in the donor superficial temporal artery (STA) following previous STA-middle cerebral artery bypass surgery (n=1). Patients were followed clinically and radiographically.

RESULTS

Bypass surgery was successful in all patients. At a mean follow-up of 53.4 months, the short-term patency rate was 100%, and the long-term rate was 92.3%. Twelve patients had an excellent clinical outcome of Glasgow Outcome Scale (GOS) 5, and one case had GOS 3. Procedure-related complications were a temporary dysthesia on the graft harvest hand (n=1) and a hematoma at the graft harvest site (n=1), and these were treated successfully with no permanent sequelae. In one case, spasm occurred which was relieved with the introduction of mechanical dilators.

CONCLUSION

EC-IC bypass using a RAIG appears to be an effective treatment for a variety of cerebrovascular diseases requiring proximal occlusion or trapping of the parent artery.

Salvage techniques for STA-MCA bypass

Superficial temporal artery-to-middle cerebral artery (STA-MCA) bypass is a well-established, indispensable neurosurgical procedure. It is technically challenging, and surgeons must be prepared for unexpected problems. The present report describes four cases where problems arose that resulted in graft occlusion. None of these problems was directly related to the anastomosis procedure, and they occurred from early in the operation (e.g., STA preparation) to late (e.g., skin closure). In all cases, the salvage procedures used were successful, and postoperative angiography demonstrated good bypass patency.

An anatomic study for a modified technique for bypass of the external carotid artery to the proximal middle cerebral artery

We aimed to evaluate whether bypass of the external carotid artery (ECA) to the middle cerebral artery (MCA) can be established by a short saphenous vein graft in order to increase the anastomosis patency. The method was performed to ten adult cadaver sides. We described a modified technique for bypass of the ECA to the M2 segment of MCA. The diameters of the vessels and graft length were measured by using an electronic micrometer. The mean diameter of the superior, middle, and inferior trunks of the MCA with trifurcation were 1.7 +/- 0.15, 2.2 +/- 0.25, and 2.0 +/- 0.2 mm, respectively, whereas the mean diameter of the superior and inferior trunks of the MCA with bifurcation were 2.1 +/- 0.2 and 2.3 +/- 0.3 mm, respectively. The mean diameter of the ECA was 3.75 +/- 0.4 mm. The mean length of the saphenous vein graft was 71.5 +/- 3.9 mm. The high-flow ECA to proximal MCA bypass using a short venous graft can supply enough blood flow to establish cerebral revascularization with a straighter route.

Microsurgical anatomy of cerebral revascularization. Part I: Anterior circulation

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

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

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

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.

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.