Virtually bloodless posterior midline exposure of the lumbar spine using the "para-midline" fatty plane

The authors have developed a "para-midline" approach to the posterior lumbar spine using a virtually avascular surgical plane not previously described in the literature. It was their purpose to document consistent MRI presence of this plane and to prospectively evaluate its clinical use in terms of blood loss.

Fifty consecutive patients undergoing primary lumbar surgery on 1-3 levels were prospectively enrolled from September 2014 to May 2015. The para-midline approach was used in all cases. The deep lumbar fascia is longitudinally incised on either side of the spinous processes instead of directly in the midline, which reveals the para-midline fatty plane. Blood loss during the approach and overall blood loss were recorded for all patients. MRIs from each patient were reviewed by an experienced neuroradiologist to determine the presence of the para-midline fatty plane.

There was no recorded blood loss during the approach for all procedures. The average overall blood loss was 60 cc (20-200 cc). No patient required a transfusion intraoperatively or postoperatively. The fatty para-midline plane was noted on preoperative MRI at all operated levels in all patients. The average width of this plane was 6.5 mm (2-17 mm).

The para-midline approach for lumbar surgery is associated with less blood loss than traditional, subperiosteal exposure techniques. The fatty interval through which this approach is made is universally present and identifiable on MRI. The authors offer this approach as a means of decreasing the risks associated with blood loss and transfusion with posterior lumbar surgery.