The plastic surgeon's role in extracranial-to-intracranial bypass using a reverse great saphenous vein graft

Neuroplastics approach to cerebrovascular bypass surgery: the way forward for centres with small to medium volume caseload

PURPOSE

Cerebral bypasses are technically challenging procedures essential in the neurosurgeon's armamentarium. Decreasing surgical indications leading to reduced caseload has resulted in less than ideal clinical outcomes, particularly in low to medium volume centres. We describe the neuroplastics approach to cerebral bypasses in the largest retrospective series to date and demonstrate how this approach has been able to smoothen the learning curve and achieve consistent outcomes approximating that of high-volume centres.

METHODS

A retrospective study was conducted. All patients who received a bypass were classified into those with bypasses performed using the neuroplastics approach (NP group) and those performed by solo neurosurgeons (Solo group). Technical outcomes and clinical outcomes were compared.

RESULTS

There were 19 patients in the NP group and 50 patients in the Solo group. There were 17 patients in the NP group with double-barrel bypasses and 2 with single-barrel bypasses (total of 36 direct anastomoses) and 45 patients of the Solo group with single-barrel bypasses and 5 patients with conversion to indirect bypasses. Patients in the Solo group were more likely to experience a postoperative stroke in the bypassed territory (Solo, 17.8%; NP, 0%; p = 0.008). Although not statistically significant, there was a difference in the proportion of patients with conversion to indirect bypass (Solo, 10.0%; NP, 0%), postoperative anastomotic bleed (Solo, 8.9%; NP, 0%), and long-term patency (Solo, 93.9%; NP, 100%). Patients in the NP group had a shorter median length of stay (NP, 3 [2 - 7] days; Solo, 6 [5 - 9] days; p = 0.005) and 1-year modified Rankin scale approached significance (NP, 0 [0 - 0]; Solo, 0 [0 - 2]).

CONCLUSION

Our experience supports the adoption of a neuroplastics approach to the training and execution of cerebrovascular bypasses in small to medium volume centres. This collaboration allowed us to deliver cerebral bypasses to indicated patients with excellent outcomes.

Extracranial-Intracranial Microsurgical Bypass Using a Y-Shaped Vein Graft From the Hand

While extracranial-intracranial (EC-IC) bypass is commonly performed by neurosurgeons with specific expertise in cerebrovascular surgery, they can also be performed together with microvascular plastic surgeons. At our institution, some EC-IC bypass cases have evolved to be performed by neurosurgeons and plastic surgeons in a combined approach. Given the plastic surgeons' expertise and volume of experience in performing microvascular surgery, their skills are utilized in performing the donor vessel dissection as well as the bypass itself. This paper outlines a Canadian perspective on collaboration between plastic surgeons and neurosurgeons in performing EC-IC bypass along with a case report illustrating the use of a dorsal hand Y-shaped vein graft for EC-IC bypass, which has not been described in the literature to date.

A Systematic Review of Microsurgical Pedicle Lengthening in Free Tissue Transfer

INTRODUCTION

Traumatic injuries that require free tissue flaps for reconstruction may require vascular pedicle extension between the flap and recipient vessels to form a clear anastomosis. Currently, a variety of techniques are used, each with their own potential benefits and harms. In addition, reports in the literature conflict on the reliability of pedicle extensions of vessels in free flap (FF) surgery. The objective of this study is to systematically assess the available literature about outcomes of pedicle extensions in FF reconstruction.

METHODS

A comprehensive search was performed for relevant studies published up to January 2020. Study quality was assessed using the Cochrane Collaboration risk of bias assessment tool and a set of predetermined parameters was extracted by 2 investigators independently for further analysis. The literature review yielded 49 studies investigating pedicled extension of FF. Studies meeting inclusion criteria underwent data extraction focusing on demographics, conduit type, microsurgical technique, and postoperative outcomes.

RESULTS

The search yielded 22 retrospective studies totaling 855 procedures from 2007 to 2018 in which 159 complications (17.1%) were reported in patients aged between 39 and 78 years. Overall heterogeneity of articles included in this study was high. Free flap failure and thrombosis were the 2 most prevalent major complications noted: vein graft extension technique had the highest rate of flap failure (11%) in comparison with the arterial graft (9%) and arteriovenous loops (8%). Arteriovenous loops had a rate of thrombosis of 5% versus 6% in arterial grafts and 8% in venous grafts. Bone flaps maintained the highest overall complication rates per tissue type at 21%. The overall success rate of pedicle extensions in FFs was 91%. Arteriovenous loop extension resulted in a 63% decrease in the odds of vascular thrombosis and a 27% decrease in the odds of FF failure when compared with venous graft extensions (P < 0.05). Arterial graft extension resulted in a 25% decrease in the odds of venous thrombosis and a 19% decrease in the odds of FF failure when compared with venous graft extensions (P < 0.05).

CONCLUSIONS

This systematic review strongly suggests that pedicle extensions of the FF in a high-risk complex setting are a practical and effective option. There may be a benefit to using arterial versus venous conduits, although further examination is warranted given the small number of reconstructions reported in the literature.

EC-IC bypass for cerebral revascularization following skull base tumor resection: Current practices and innovations

Complex skull base tumors can involve critical vessels of the head and neck. To achieve a gross total resection, vessel sacrifice may be necessary. In cases where vessel sacrifice will cause symptomatic cerebral ischemia, surgical revascularization is required. The purpose of this paper is to review cerebral revascularization for skull base tumors, the indications for these procedures, outcomes, advances, and future directions.

Indications and Outcomes of Prophylactic and Therapeutic Extracranial-to-intracranial Arterial Bypass for Cerebral Revascularization

Background:

Extracranial-to-intracranial (EC-IC) arterial bypass is a technically demanding procedure used to treat complex cerebral artery diseases. The indications, proper surgical techniques, and outcomes of this procedure have been under debate over the recent decades.

Methods:

Between January 2004 and December 2012, 28 patients, including patients with cerebral artery occlusion, intracranial aneurysm, cranial base tumor, and Moyamoya disease, underwent EC-IC bypass. Patients’ records were retrospectively reviewed for demography, indications, complications, high-flow versus low-flow bypass, patency rate of bypass, and neurological outcome. The patients were sorted into prophylactic (n = 16) and therapeutic (n = 12) groups based on the preoperative presentation of their neurological symptoms. Follow-up evaluation was performed at a mean of 32.7 ± 24.3 months.

Results:

The overall patency rate of bypass was 100%, the postoperative stroke rate was zero, and the surgical complication rate was 14.3%. There was no significant difference in the bypass patency rate between the 2 groups or between the high-flow and low-flow bypass patients. Patients who underwent prophylactic bypass had minimal surgical and total complications (P = 0.03 and P < 0.01, respectively) and a better neurological outcome. Surgical complications were more common in patients who underwent therapeutic bypass (25%).

Conclusions:

The collaboration of neurosurgeons and plastic surgeons in performing EC-IC bypass can result in excellent outcomes with a high bypass patency rate and few complications, particularly for prophylactic EC-IC bypass.

Viability of anastomoses with coupler in extra-intracranial bypass: cadaveric study

BACKGROUND

The time required to perform an anastomosis in extra-intracranial bypass is approximately 20 to 60 minutes. The search for alternative methods to reduce the ischemic time remains vital.

OBJECTIVE

To evaluate Coupler anastomosis for extra-intracranial bypass in cadavers.

METHODS

In 8 fresh adult cadavers, the saphenous vein and radial artery were used as donor vessels. The superficial temporal and the extracranial internal and external carotid arteries were dissected. A wide craniotomy with a sylvian fissure opening was performed, exposing the middle cerebral and supraclinoid internal carotid arteries. The Coupler devices were tested in all 8 cadavers. The diameter of the donor and recipient vessels as well as the time required to perform the anastomosis were measured. Bypass permeability was evaluated by injecting saline solution under pressure, checking for leaks.

RESULTS

The anastomoses were successfully performed in all specimens. The size of the head of the fitting Coupler required the performance of a wide craniotomy (6 × 6 cm) and a wide opening of the sylvian fissure. The time required to perform each anastomosis ranged from 4 to 7 minutes, being easier with the radial artery than with the saphenous vein.

CONCLUSION

Coupler devices are helpful to perform the anastomoses, because they significantly reduce ischemia time. Their use is easier at the M1 segment, just before the bifurcation and after takeoff of the lenticulostriate arteries, and in the M2 segment. It would be advisable to have a smaller coupling system, allowing maneuverability in the deeper areas where space is limited.