gms | German Medical Science

Objective: The posterior cervical foraminotomy is a common applied strategy to treat foramen stenosis or lateral herniated disc of the cervical spine. The rate of wrong level surgery is presumed to be higher than often described in the current literature. Correct level surgery of lower segments of the cervical spine can be challenging due to poor fluoroscopic conditions especially in obese patients. Aim of this study was to lower the risk of wrong level surgery and simultaneously reduce the approach dimensions through performing navigation guided posterior cervical foraminotomies in overly obese patients.

Methods: After standard positioning an intraoperative fluoroscopy was obtained to specify spinous process of C7. We also attempted to fluoroscopically visualize treatment levels in every patient as comparative reference. This was then followed by a minimal midline incision to fixate the reference array on the spinous process. We then performed an intraoperative Dyna-CT with a 3D robotic C-arm followed by an auto-registration process. The approach was extended under navigational guidance. Bony decompression of the neuroforamen was also performed with navigational aid. Size of skin incisions were compared to a fluoroscopic planned virtual approach in each case. Integrity of the bony structures was evaluated on the postoperative images and on flexion-extension x-rays.

Results: A total of 13 Patients, 7 women and 6 men, underwent navigated posterior cervical foraminotomies at our department from March 2017. Mean patient BMI was 34.7. No wrong level surgeries were detected in any of the cases on the follow-up CT scans. Cervical instabilities of the treated segment could be excluded through flexion-extension x-rays in all cases at 3-month follow-up. On average skin incisions were reduced by 14% thus leading to a reduction of the subcutaneous and subfascial approach dimensions.

Conclusion: This study demonstrates that a navigated posterior cervical foraminotomy of the lower cervical spine in obese patients can be advantageous for avoidance of wrong level surgery. Additionally, a significant reduction in approach dimensions presumably leads to a reduction of peri- and postoperative morbidities e.g. blood loss, infection rates and consecutive iatrogenic instabilities.