Introduction: The treatment strategy for insufficiency syndromes and complex aneurysms of the vertebrobasilar system may involve revascularization of the upper posterior circulation (UPC) (including the superior cerebellar [SCA] and posterior cerebral arteries [PCA]). There are multiple bypass options, each having their own merits and demerits. However, there have been no previous assessments of the use of a superficial temporal artery graft (STAg) in a bypass from the internal maxillary artery (IMA) to the UPC. This study aimed to assess the surgical anatomy and feasibility of the IMA-STAg-UPC bypass.
Methods: Fourteen cadaver heads were studied. The STAg was harvested proximally from about 15mm below the zygomatic arch. The lateral triangle of the middle fossa was used to expose the IMA and a subtemporal approach was used to complete the IMA-STAg-UPC bypass.
Results: The IMA-STAg-UPC bypass was successfully performed in all specimens. The average length of the STAg required for the IMA-STAg-SCA bypass was 46.4mm while that for IMA-STAg-SCA bypass was 49.5mm. Majority (83%) of the STAg had a diameter of =2mm distally with the average distal diameter of STAg being 2.3mm. The average diameters of the SCA and PCA were found to be 1.9mm and 3.0mm, respectively, at the point of anastomosis.
Conclusions: Our investigation reveals that the use of STAg for the proposed bypasses is anatomically feasible and provides a suitable caliber match between the bypass components. This study provides the anatomical basis for the clinical assessment of the proposed technique for the management of complex vertebrobasilar lesions. The proposed bypass may add to the current armamentarium of cerebrovascular surgeons for addressing complex lesions of the posterior circulation.
Patient Care: 1. Introducing a new type of bypass for upper posterior circulation aneurysms that helps surgeons in treating complex distal basilar aneurysms as well as vascular insufficiency syndromes of the posterior circulation
2. Proposing a method for harvesting a better interpositional STA graft without the need for remote incisions to harvest similar grafts like RAG
Learning Objectives: 1. Description of our technique for harvesting IMAX without the need for zygoma removal
2. Description of our proposed technique for harvesting the STA at the region below the zygomatic arch to obtain a better interpositional graft
3. Description of the technique and indications for an IMAX-UPC bypass