33rd Annual Scientific Meeting proceedings

Introduction
Lateralized C2-C3 arachnoid diverticulum (AD) is mainly approached by hemilaminectomy, which is considered challenging mostly due to hemorrhage reported in the literature. This could be explained by the particular perimedullar vascular environment represented by the interarcuate branches (IAB). This study aims to describe the surgical technique for C2-C3 hemilaminectomy with a particular focus on the hemostasis of the encountered perimedullar vascular structures and reports its clinical application in 8 dogs.

Materials and methods
The surgical technique was described in eight fresh cadavers. After standard C2-C3 hemilaminectomy, the interarcuate ligament and the IAB were exposed. Interarcuate branches were closed using three vascular clips, one dorsally, and two ventrally and severed between the clips. The approach accuracy was recorded. This technique was subsequently used in 8 clinical cases. 

Results
In the cadaveric study, IAB were identified in each dog; their locations were consistent. After the transection of the IAB, the ipsilateral, ventral, and dorsal aspects of the spinal cord could be palpated. Eight dogs (body weight: 23.9±10.4 kg) with C2-C3 lateralized AD treated by cyst excision with this technique, did not experience hemorrhage. In all dogs, treatment of AD was completed. The neurological status of seven dogs improved immediately postoperatively. One dog died from severe hypoventilation 24 hours post-operatively. 

Discussion/Conclusions
Vascular clipping of the IAB could be performed safely in dogs during C2-C3 hemilaminectomy to avoid bleeding during the approach and to provide good access to the lateral part of the vertebral canal allowing surgical treatment of lateralized AD.