# The utility of preoperative computed tomography-guided screw marking in thoracic spine surgery

## TL;DR

Preoperative CT-guided screw marking helps prevent wrong-level surgeries in thoracic spine operations and improves surgical accuracy.

## Contribution

A novel preoperative CT-guided screw marking technique is introduced to prevent wrong-level thoracic spine surgeries.

## Key findings

- WLS occurred in only one patient in the control group and none in the screw group.
- Surgical complications were similar between groups.
- CT-guided screw marking allows precise intraoperative vertebral localization.

## Abstract

Wrong-level surgery (WLS) is a preventable yet severe complication in spinal surgery, particularly for pathologies located in the thoracic spine, where localizing the intended level is more challenging compared to the lumbar or cervical spine, which have more distinct landmark structures and fewer vertebral bodies.

Evaluate the impact of preoperative, computed tomography (CT)-guided screw marking on avoiding WLS and optimizing intraoperative workflows.

We conducted a retrospective case-control study at Bern University Hospital, enrolling all patients treated with thoracic spinal surgery between February 2017 and August 2022. Patients that received preoperative, CT-guided screw marking in the pedicle at the index level were compared to those without preoperative marking. Data included clinical features, radiological parameters, and complications. Primary endpoint: occurrence of WLS. Secondary endpoints: duration of intraoperative fluoroscopy, operating room (OR) occupancy time, and complications.

A total of 117 patients were included: 71 in the screw group and 46 in the control group. The mean age was 54 (±16) years. Significant differences were found in the indication for surgery (p = 0.002). No significant differences were observed in duration of intraoperative fluoroscopy, effective dose, or total OR occupancy time. WLS occurred in only one patient in the control group and none in the screw group. Surgical complications were similar between groups.

We present a safe technique with a low complication rate for preoperative marking of the index vertebra before thoracic spinal surgery, allowing spine surgeons to eliminate the risk of WLS.

•CT-guided screw marking eliminates wrong-level surgery in thoracic spine cases•Fiducial screw placement enables precise intraoperative vertebral localization•Safe technique for screw-marking in thoracic spine surgery with low complication rate

CT-guided screw marking eliminates wrong-level surgery in thoracic spine cases

Fiducial screw placement enables precise intraoperative vertebral localization

Safe technique for screw-marking in thoracic spine surgery with low complication rate