Two-step osteotomy/discectomy through cannulated screw (TOCS) technique for en bloc resection of spine tumor: surgical technique and preliminary results.

Abstract

We have developed a novel technique for osteotomy/discectomy during en bloc resection of spine tumors named two-step osteotomy/discectomy through cannulated screw (TOCS). This study aims at describing the procedure of TOCS technique and assessing its efficiency and safety. We retrospectively reviewed fourteen patients who underwent en bloc resection for spine tumors using TOCS technique in our center between August 2018 and September 2022. The technique was based on a specially designed "slotted" cannulated screw which was a cannulated screw with a longitudinal slot to provide the accessibility of T-saw. During osteotomy/discectomy, the "slotted" cannulated screw was inserted obliquely along the plane between the dura and the posterior wall of spine in light of the planned osteotomy/discectomy plane under routine fluoroscopic imaging guidance. The T-saw was introduced through the screw, and the osteotomy/discectomy was performed sequentially in two steps under the guidance of the screw by turning the slot away and toward the dura. The intra-/perioperative complication, neurological function (determined by Frankel grading), surgical margin (determined by a pathologist using AJCC R system), follow-up details were documented. The mean duration of surgery was 599.3 (360-890)min with a mean volume of intra-operative hemorrhage of 2021.4 (800-5000)mL. The intra-/perioperative complications were found in four patients (28.6%). R0 and R1 resections were achieved in nine and five patients, respectively. There was no R2 resection. After a mean follow-up period of 30.6 (10-67)months, all patients were alive except one patient died ten months after surgery due to unrelated cause. No recurrence and implant failure were found. Thirteen patients (92.9%) exhibited completely normal neurological function same as their preoperative neurological status. Using TOCS technique can facilitate a precise, complete and safe osteotomy/discectomy procedure during en bloc resection for spine tumor without the aid of intra-operative navigation.