Double-Interposition Bypass: Technical Case Report of a Novel Intraoperative Bypass Salvage Technique

Complex cerebrovascular bypass operations may confer an increased risk of intraoperative complications, such as graft thrombosis. Novel techniques are needed to optimize the management of these challenging cases.

A woman in her late 20s was incidentally diagnosed with a 1.5-cm basilar apex aneurysm, which grew to 3.5 cm over 2 years of active surveillance. Definitive treatment was then recommended with flow reversal and Hunterian ligation of the basilar trunk planned as a radial artery graft (RAG) bypass: M2 (S-Ec) RAG (E-Sc*) P2. Intraoperative graft thrombosis prompted multiple attempted salvage maneuvers; however, complete excision and repeat anastomosis were ultimately required. The procedure was completed using a novel double-interposition technique, with ligation of the index RAG approximately 1 cm proximal to the distal anastomosis (final bypass: M2 [S-Ec*] RAG [E-Ec*] RAG' [E-Sc] P2). These technical modifications yielded a less deep recipient site for the repeat bypass and an end-to-end anastomosis rather than an end-to-side anastomosis, collectively facilitating a more efficient and facile salvage. The patient recovered well from surgery, and flow reversal was successfully achieved within the aneurysm.

Despite the increased risk of intraoperative thrombosis with complex cerebrovascular bypass operations, facility with salvage techniques can lead to technically and clinically excellent outcomes. We report the successful use of a novel fourth-generation double-interposition bypass that shortens the working distance and uses a more favorable anastomosis technique. This bypass may facilitate safe and efficient microsurgery in patients who require complete revision of an intracranial-intracranial construct.