Instrument Tracking Reduces Radiation Exposure and Increases Efficiency in Prone Lateral Lumbar Interbody Fusion: A...

Minimally invasive spine surgery, particularly lateral lumbar interbody fusion, offers advantages over open surgery, including reduced blood loss and shorter hospital stays. The prone lateral lumbar interbody fusion (PL-LIF) is an evolution of lateral lumbar interbody fusion that enables posterior instrumentation without repositioning, enhances sagittal correction, and may improve operative efficiency. However, concerns remain regarding prolonged psoas retraction and increased radiation exposure. While instrument tracking technologies have improved workflow and reduced radiation in other minimally invasive surgeries, such as minimally invasive transforaminal lumbar interbody fusion, their role in PL-LIF remains unstudied. This study evaluates the impact of instrument tracking on psoas retraction time, radiation exposure, and procedural efficiency in PL-LIF.

A retrospective analysis reviewed PL-LIF procedures using instrument tracking technology at a single institution over 7 months. Operative times (minutes), radiation exposure (mGy and number of x-ray images), and patient-reported outcome measures (PROMs) were analyzed. The dataset was divided into temporal quartiles based on the chronological order of surgical cases to evaluate the impact of learning over time. PROMs were also reported.

A total of 52 consecutive PL-LIF levels across 39 patients were included. The surgeon had 2 years of PL-LIF experience but had no prior experience with instrument tracking before the first case in the dataset. Median retractor time across the entire study was 17.43 minutes (interquartile range [IQR]: 7.48). From first to final quartile, the median retractor time consistently decreased from 20.9 to 14.7 minutes (-30%, P = 0.028). Comparing the first and the fourth quartile, the frequency of retractor times less than the 20-minute threshold increased from 46% to 85% (χ² = 4.25, P = 0.04). Median radiation exposure per level was 7.55 mGy (IQR: 4.40), corresponding to 13 x-rays images taken (IQR: 7). Linear regression revealed significant decreases in retractor time in the third (-8.95 minutes, P < 0.001) and final quartiles (-7.55 minutes, P < 0.001). Patient-reported outcome measures improved from baseline to 6 and 12 months, with Oswestry Disability Index decreasing 14.6 and 18.6 points, Veterans RAND 12-Item Physical Component Summary increasing 10.0 and 13.1 points, and Zurich Claudication Questionnaire Symptom Severity and Physical Function decreasing 20.1 to 25.8 and 19.7 to 25.5 points, respectively. All changes exceeded established minimal clinically important differences (all P < 0.001).

Prolonged retractor times and substantial radiation associated with the PL-LIF can be dramatically reduced with instrument tracking. Intraoperative radiation exposure was significantly reduced compared with previous studies, with a minimal number of x-rays images required from study onset. Psoas retraction time significantly decreased after an inflection point at 15 cases, ultimately falling below 15 minutes and correlating with adherence to the recommended 20-minute threshold in 85% of cases during the final quartile. Instrument tracking can substantially decrease retractor time and radiation exposure in PL-LIF.

Instrument tracking in PL-LIF improves efficiency and safety, reducing psoas retraction time and radiation while maintaining 12-month PROM gains.