General Session: MIS-4
Presented by: J. Larson - View Audio/Video Presentation (Members Only)
J. Larson(1), B. Hathaway(1)
(1) Coeur d'Alene Spine & Brain, PLLC, Coeur d'Alene, ID, United States
Introduction: MIS TLIF is a promising treatment for some degenerative spine conditions. Reported advantages of MIS TLIF vs. open surgery include less blood loss, shorter operative times, shorter length of stay, earlier mobilization, and quicker recovery. The learning curve for the MIS TLIF procedure remains an obstacle to surgeon acceptance. The current study compares two fundamentally different approaches to MIS TLIF. Both approaches utilize a trans-tubular decompression and interbody fusion followed by percutaneous pedicle screw fixation. The approaches vary by the method of interbody fusion. In the Direct Visualization Approach (DVA) familiar neural elements, such as the passing nerve root to the intervertebral disc space of interest are routinely exposed and used as reference points for orientation to perform interbody fusion. In the Pedicle Based Approach (PBA) the pedicle inferior to the intervertebral disc space of interest is used as a reference point for orientation to perform the interbody fusion while the neural elements are generally not exposed.
Methods: The authors retrospectively studied 115 consecutive cases over a 24-month period of patients who had back pain with radiculopathy and/or neurogenic claudication treated by MIS TLIF. Surgeries were performed by a single surgeon (JJL). 50 patients had MIS TLIF by DVA and 65 patients had MIS TLIF by PBA. The authors compared pre-operative and post-operative Oswestry Disability Index (ODI), blood loss, operative time, length of stay, and major and minor complications.
Results: The average pre-operative to post-operative change in ODI was 37% improvement for DVA and 46% improvement for PBA (p 0.15). The average blood loss was 163 ml for DVA and 125 ml for PBA (p 0.07). The average operative time was 154 minutes for DVA and 118 minutes for PBA (p 0.00001). The average length of stay was 55 hours for DVA and 30 hours for PBA (p 0.00001). There were no major complications in either group. There were 3 minor complications (6% incidence) in the DVA group and 1 minor complication (1.5 % incidence) in the PBA group.
Discussion: The DVA and PBA MIS TLIF techniques differ primarily in the method of interbody fusion. A key difference between the techniques is whether or not neural elements are routinely exposed prior to performing the interbody fusion. Both techniques were performed safely and without any major complications. Both techniques offered relief of the pre-operative symptoms. The PBA technique was superior to the DVA technique in ODI improvement, blood loss, operative time, length of stay, and incidence of minor complications. The difference was statistically significant for operative time and length of stay.
Conclusion: This retrospective study of two MIS TLIF techniques shows that a Pedicle Based Approach to interbody fusion, without exposure of neural elements, can be performed safely and with improved efficiency over a Direct Visualization Approach to interbody fusion that depends on exposure of neural elements to perform the interbody fusion. In essence, an MIS TLIF can be performed without the added risk of exposing the neural elements. This finding supports the development of more systematic approaches to MIS TLIF that may reduce the learning curve and achieve a higher surgeon acceptance rate.