Anatomic Considerations of Intervertebral Disc Perspective in Lumbar Posterolateral Approach via Kambin's Triangle: Cadaveric Study

STUDY DESIGN Anatomical study. PURPOSE To evaluate the anatomy of intervertebral disc (IVD) area in the triangular working zone of the lumbar spine based on cadaveric measurements. OVERVIEW OF LITERATURE The posterolateral percutaneous approach to the lumbar spine has been widely used as a minimally invasive spinal surgery. However, to our knowledge, the actual perspective of disc boundaries and areas through posterolateral endoscopic approach are not well defined. METHODS Ninety-six measurements for areas and dimensions of IVD in Kambin's triangle on bilateral sides of L1-S1 in 5 fresh human cadavers were studied. RESULTS The trapezoidal IVD area (mean±standard deviation) for true working space was 63.65±14.70 mm2 at L1-2, 70.79±21.88 mm2 at L2-3, 99.03±15.83 mm2 at L3-4, 116.22±20.93 mm2 at L4-5, and 92.18±23.63 mm2 at L5-S1. The average dimension of calculated largest ellipsoidal cannula that could be placed in IVD area was 5.83×11.02 mm at L1-2, 6.97×10.78 mm at L2-3, 9.30×10.67 mm at L3-4, 8.84×13.15 mm at L4-5, and 6.61×14.07 mm at L5-S1. CONCLUSIONS The trapezoidal perspective of working zone of IVD in Kambin's triangle is important and limited. This should be taken into consideration when developing the tools and instruments for posterolateral endoscopic lumbar spine surgery.