A Cadaveric Comparison of Discectomy Performance During Transforaminal Lumbar Interbody Fusion Approach Using an Endoscopic Technique versus a Minimally Invasive Tubular Approach.

ABSTRACT

STUDY DESIGN: Cadaveric study. OBJECTIVE: Compare discectomy performance between transforaminal lumbar interbody fusion (TLIF) done via an endoscopic versus a tubular technique. SUMMARY OF BACKGROUND DATA Performance of an adequate discectomy is essential to lumbar fusion when performing a TLIF. Previous cadaveric studies comparing open and minimally invasive techniques have reported 36.6%-80% discectomy. There is controversy whether an endoscopic TLIF (E-TLIF) can allow for an adequate discectomy. MATERIALS/METHODS: An E-TLIF was performed on 14 discs (T12-L5) and a minimally invasive tubular TLIF (T-TLIF) was performed on 15 discs (T12-L4, L5-S1). Fellowship trained surgeons performed the TLIFs. Each disc was transected after discectomy and a digital image was analyzed using an imaging processing software to determine the percent of discectomy. Each quadrant of the discectomy was compared. Quadrant one was defined as the left posterior-ipsilateral quadrant of the disc, with each quadrant numbered 2-4 clockwise around the disc. The time to perform the discectomy was compared. Pedicle screws were placed contralaterally to the TLIF and the change in interpedicular distance was compared between techniques after expandable cage implantation as a marker for indirect decompression. A student's t-test was used to determine statistical significance. RESULTS: There was no difference in discectomy performance between techniques (48.86%+/-6.98% T-TLIF vs. 50.26%+/-7.38% E-TLIF, P=0.61). There was no statistical difference between T-TLIF vs E-TLIF at quadrants 1, 3 and 4. There was a difference in discectomy performance at quadrant 2 (39.02%+/-10.18% T-TLIF vs 50.13%+/-14.00% E-TLIF, P=0.02). There was no statistical difference between interpedicular distance created (2.20 mm+/-1.97 mm T-TLIF vs 1.36 mm+/-1.82 mm E-TLIF, P=0.24). E-TLIF took less time than MIS-TLIF (20.00 min+/-7.12 min vs 15.22 min+/-4.42 min, P=0.048). CONCLUSION: Our cadaveric study demonstrates that an adequately performed E-TLIF discectomy may be comparable to a T-TLIF discectomy. Further research is required to maximize the efficiency and instrumentation of this technique.