Can computer-assisted surgery reduce the effective dose for spinal fusion and sacroiliac screw insertion?

Abstract

Background: The increasing use of fluoroscopy-based surgical procedures and the associated exposure to radiation raise questions regarding potential risks for patients and operating room personnel. Computer-assisted technologies can help to reduce the emission of radiation; the effect on the patient's dose for the three-dimensional (3-D)-based technologies has not yet been evaluated.

Questions/purposes: We determined the effective and organ dose in dorsal spinal fusion and percutaneous transsacral screw stabilization during conventional fluoroscopy-assisted and computer-navigated procedures.

Patients and methods: We recorded the dose and duration of radiation from fluoroscopy in 20 patients, with single vertebra fractures of the lumbar spine, who underwent posterior stabilization with and without the use of a navigation system and 20 patients with navigated percutaneous transsacral screw stabilization for sacroiliac joint injuries. For the conventional iliosacral joint operations, the duration of radiation was estimated retrospectively in two cases and further determined from the literature. Dose measurements were performed with a male phantom; the phantom was equipped with thermoluminescence dosimeters.

Results: The effective dose in conventional spine surgery using 2-D fluoroscopy was more than 12-fold greater than in navigated operations. For the sacroiliac joint, the effective dose was nearly fivefold greater for nonnavigated operations.

Conclusion: Compared with conventional fluoroscopy, the patient's effective dose can be reduced by 3-D computer-assisted spinal and pelvic surgery.

Level of evidence: Level II, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Fig. 1A–C

(A) Transverse, (B) sagittal, and (C) coronal planes of a 3-D scan of the lumbar spine are being reconstructed of 100 single 2-D images. To acquire these images, the C-arm rotates 190° around the patient. The single images then are processed by the attached work station and the CT-like data set then is sent to the navigation system.

Fig. 2A–D

The preoperative (A) lateral and (B) AP views of the lumbar spine are being made with the same C-arm as are the 3-D scans. The postoperative control (C) lateral and (D) AP views after spinal fusion show the correct placed pedicle screws. In both groups (navigated and conventional) these images usually are acquired after surgery and in both groups these images have been applied to the phantom.

Fig. 3

An anthropomorphic male Alderson-Rando Phantom consists of 35 axial segments containing human skeleton and material with similar properties to soft tissues.

Fig. 4

The Phantom was irradiated according to the scan protocols. The real use of the C-arm was simulated on the phantom, which was positioned in the same manner as a patient on the operating room table.

Fig. 5

Standard hospital equipment was used for irradiation of the phantom. The same equipment was used for the real operations.

Fig. 6

Radiation time is reduced by 3-D navigation compared with the conventional approach for lumbar spinal fusion.

Fig. 7

The total duration of surgery is relatively similar comparing 3-D navigation with conventional lumbar spinal fusion.

Fig. 8

The effective dose is less for 3-D–navigated operations at the spine and at the pelvis. SI = sacroiliac.