Introduction: The occipital artery (OA) is commonly used as a donor for posterior circulation bypass procedures. Localization of OA during harvesting is important to prevent inadvertent damage to the donor. The proximal portion of the OA is found in the occipital groove. The occipitomastoid suture (OMS) is located between the occipital bone and the mastoid portion of the temporal bone. This study aimed to assess the relationship between the OMS and the occipital groove, in order to facilitate localization of the proximal portion of OA while harvesting it for bypass
Methods: Thirty-five dry skulls were assessed bilaterally(n=70) to study the bony landmarks that can be used to identify and locate the proximal segment of OA. The occipital groove (OG) was bilaterally identified in each skull and its shape was classified into canal, groove or impression. The asterion was located and the origin of OMS was identified. The OMS was then followed inferiorly to assess its relationship with the course of the OA (medial, lateral or central)
Results: In 71.5% of the specimens the OA ran in a groove, while it carved an impression in the rest of the cases (28.5%). In none of the specimens the OA was found to run in a bony canal. In 68.6% of the cases, the OMS was found to be medial to the OA groove or impression while in 31.4%, it ran centrally through the OA groove or impression. The OMS was never found lateral to the OA
Conclusions: The OMS is a key landmark for localizing the proximal OA. The OMS can be followed inferiorly from the asterion to the OA groove, thereby localizing the proximal OA. Inadvertent damage to the proximal OA may be avoided by identifying the OMS and dissecting medial to it, since in majority of cases, the proximal OA will be located lateral to it
Patient Care: Using the occipitomasoitd suture as a landmark for identification of proximal occipital artery will help prevent inadvertent damage to it, thereby enabling longer graft lengths and greater potential for the use OA as a donor for posterior circulation revascularization, leading to better patient outcomes
Learning Objectives: 1. To understand the relationship between the occipital groove and the occiptomastoid suture
2. To understand the potential use of occipitomastoid suture as a landmark to identify the proximal segment of OA in the occipital groove