Intraoperative disc level marking with needle: a technical note and prospective study on 30 patients

Wrong-level surgery is a rare but unresolved issue in spine surgery. Some proposed protocols with high success rates, but it remains a risk with potential complications for the patient. Surgical navigation offers more accurate surgery, without additional irradiation related to the imaging device, in order to optimize the surgical guidance.

We describe our institutional technique with a needle placed under fluoroscopy at 3 cm from the incision line at the disc level to be operated, in order to guide the surgical approach; and we report a prospective evaluation of all patients during a six-month period operated by microdiscectomy for symptomatic lumbar discus hernia, whose hernia level was landmarked with this technique. We collected demographic, clinical-such as visual analog scale (VAS) of pain and Oswestry disability index (ODI) scores-operative and irradiation data for effective dose calculation.

Thirty patients were included in the study. No wrong-level procedure was performed. Mean time for landmarking was 2.22 [1-5] minutes. Average operative time was 54.5 [30-150] minutes. The effective dose related to the imaging device use was 0.032 (0.007-0.092) mSv. The effective dose was also correlated to body mass index and disc level (P=0.05). The operative duration, complication rate and postoperative VAS and ODI scores were similar to the current literature.

We advocate the use of percutaneous needle guidance, avoiding wrong-level microdiscectomy and helping the surgeon as a "navigation-like" device with minimal additional irradiation for the patient.