The efficacy of using an image-guided Kerrison punch in performing an anterior cervical foraminotomy - An anatomic analysis

Study Design, This study comprised two parts: first, a feasibility study to determine the efficacy of using an image-guided Kerrison punch while perfo rming a foraminotomy during an anterior cervical decompression and, second, an anatomic analysis using vector measurement to determine the distance fr om the entrance of the neuroforamen to the medial margin of the vertebral a rtery in the subaxial cervical spine. Objective. To assess the feasibility of using an image-guided Kerrison punc h when performing an anterior foraminotomy and to obtain data regarding the distance from the vertebral artery to the entrance of the neuroforamen. Summary of Background Data. The documented incidence of catastrophic iatrog enic vertebral artery injury in anterior cervical decompression is low. The use of a realtime image-guidance surgical system should reduce the risk of this complication. Methods. Twelve cadaveric cervical spines were harvested. Standard anterior cervical discectomies with bilateral foraminotomies were performed in the subaxial cervical spine using an image-guided Kerrison. Surgically signific ant morphometric data were measured using a computer-assisted image-guided surgical system. Results. Successful navigation into all neuroforamina in the subaxial cervi cal spine was attained using the image-guided Kerrison punch. The vector me asurement from the neuroforamen to the vertebral artery averaged 5.8 +/- 1. 2 mm at C3-C4, 6.5 +/- 1.6 mm at C4-C5, 7.9 +/- 1.4 mm at C5-C6, and 9.1 +/ - 1.8 mm at C6-C7. Statistically significant differences (P < 0.05) were fo und between all cervical levels except C3-C4 and C4-C5. Conclusion. An image-guided Kerrison punch may be used successfully when pe rforming cervical foraminotomies during an anterior cervical discectomy, th us eliminating the risk of potential vertebral artery injury. These data co nfirm previous findings by other authors. Knowledge of these data may aid t he spine surgeon in performing a foraminotomy during anterior cervical deco mpression.