Introduction: Current techniques for extracranial to intracranial high-flow bypass involve complex and lengthy procedures requiring cranial, cervical and graft site incisions. The internal maxillary artery (IMA) has been proposed as a donor to decrease invasiveness but is limited by its length. Interposition of a superficial temporal artery (STA) graft for high-flow IMA to middle cerebral artery (MCA) bypass has not been previously reported. We studied the anatomical feasibility of interposing a STA graft for high-flow IMA-MCA bypass and described a new approach to the proximal IMA that facilitates its harvesting.
Methods: Five cadaveric heads (10 sides) were studied. The head was turned 90 degrees to the contralateral side and the vertex tilted 15º upwards . STA was exposed from 6cm above to 1.5cm below the zygomatic arch. The distal and proximal caliber of STA was measured. After a pterional craniotomy, the IMA was isolated beneath the floor of the middle cranial fossa through a "posterolateral" approach, and transposed into the intracranial space for proximal end-to-end anastomosis to the STA. The Sylvian fissure was split to expose the insular segment of the MCA and a STA-M2 end-to-side anastomosis was completed.
Results: The average diameters of the STA at the proximal and distal ends were 2.3 ± 0.2 mm and 2.0 ± 0.1 mm, respectively. The average diameter of the distal stump of the IMA was 2.4 ± 0.6 mm. The average diameter of the MCA was 2.3 ± 0.3 mm at the site of anastomosis. The average STA length of the graft required was 67.6 ± 3.3 mm.
Conclusions: In this study we proved the STA can be used as an interposition graft to accommodate a high-flow IMA-MCA bypass. This procedure can provide an efficient and less invasive alternative for a high-flow EC-IC bypass that spares the patient a cervical and forearm incision.
Patient Care: This less invasive technique will potentially benefit patients with giant, complex ICA aneurysms or large skull base tumors where high-flow bypass is required.
Learning Objectives: This abstract, in the form of poster or oral presentation, may help neurosurgeons by: 1) Understanding that high-flow EC-IC bypass could be performed in a less invasive way, 2) Being familiar with the concept of using STA as an interposition graft for high-flow EC-IC bypass 3) Be more familiar with the possiblity of choosing IMA as the arterial donor for high-flow EC-IC bypass that spares the patient a cervical and forearm incision.