Use of intraoperative CT improves outcome of minimally invasive TLIF: a single centre retrospective cohort study.

OBJECTIVE: To provide data about surgical workflow, accuracy, complications, radiation exposure and learning curve effect in a retrospective analysis of a consecutive series of patients submitted to minimally invasive (MIS) TLIF with navigation coupled with an intraoperative mobile CT (iCT).

METHODS: We performed a retrospective analysis of data from patients who underwent single or double-level MIS-TLIF in our institution; a mobile iCT combined with a navigation system was used as the sole intraoperative imaging method to place pedicular screws; decompression and interbody fusion were performed through a 22 mm tubular retractor. Clinical data, perioperative complications, accuracy of pedicular screws and radiation exposure were analyzed. A learning curve effect on surgical time and accuracy was assessed.

RESULTS: A total of 408 screws in 100 patients were available for analysis. In all cases, spinal navigation allowed for identification of pedicular trajectories and greatly facilitated nerve root decompression through the minimally invasive approach. Overall accuracy measured with Heary classification was 95.3%. Nineteen screws (4.7%) presented a minor lateral breach (< 2mm), not clinically significant. Surgical time, blood loss and patient radiation exposure compared favorably with reported values from other series using 3D navigation. A learning curve effect on surgical time, but not on screw accuracy was identified.

CONCLUSION: MIS-TLIF can now be performed without any radiation exposure to the surgeon and OR staff, with almost absolute accuracy during screw positioning and tubular decompression. A learning curve effect on surgical time, but not on overall screw accuracy may be expected.