X-ray Instrument Tracking for LLIF Procedures: A Comparative Study of Time and Radiation Savings across 100 Consecutive Levels

Introduction: Lateral Lumbar Interbody Fusion (LLIF) is a widely used minimally invasive procedure associated with a significant radiation exposure to the staff and patient but with few if any commonly accepted navigation options. Fluoroscopy-based instrument tracking technology has been shown to decrease radiation exposure up to 90% while improving operative times, but has not been explicitly studied for lateral surgery. This multicenter study aims to evaluate the efficiency of instrument tracking technology in limiting LLIF retractor time as well as radiation exposure.

Methods: A consecutive series of 100 LLIF levels across 90 patients using x-ray tracking technology and 28 LLIF levels across 20 patients using conventional fluoroscopic imaging were performed by two surgeons. LLIFs that required angled instrumentation were excluded. Data on elapsed time, radiation exposure, and number of x-rays for both skin incision to skin closure (skin-to-skin) and retractor placement to retractor removal (retractor) were then recorded, compared, and analyzed using a spreadsheet application.

Results: The average retractor time using instrument tracking (12.3 minutes, range 5.0 - 27.5) was significantly shorter (p < 0.001) than conventional methods (14.9 minutes, range 8.1-29.5), a decrease of 17.7%. Using instrument tracking, the surgeons were 60% more likely to stay under a 20 minute retractor time. There was no significant difference (p = 0.12) between the average skin-to-skin time using instrument tracking (16.8 minutes, range 6.7-31.3) and conventional methods (18.1 minutes, range 12.3-26.2). The average number of x-rays taken using instrument tracking (11.5, range 2-35) was significantly shorter (p < 0.001) than conventional methods (44.6, range 28-76), a decrease of 74.3%.

Conclusion : The adoption of x-ray tracking in LLIF procedures significantly reduces radiation exposure to the surgical staff and patient. Additionally, x-ray tracking reduces retractor time, which has been shown to be an independent predictor of neurological complications with LLIFs. Therefore, the use of x-ray tracking can not only substantially decrease the radiation risks associated with MIS spine surgery, but also potentially decrease a key morbidity of lateral lumbar interbody fusion.