A unique triangular space has been identified by Teske
et al., measuring 0.9-1.1 ml on each side.
1 The boundaries are medial to the L5 nerve root, lateral to the S1 nerve root and the base of the triangle is above the disc of L5- S1. This space is large enough to accept the average loose disc fragment. This space tends to collect leaky disc material, a common result of trauma and surgery. Due to the curvature of the sacrum and the formation of dense scarring, regular epidural catheters and scopes have not been able to enter this scarred epidural area. Matsumoto
et al., realized that entering from the posterior aspect of the S1 neural foramin with an 18 gauge
RX-2™ Coudé® Needle and then rotating it, the curved tip allows for ventral epidural projection of a 21 gauge
VERSA-KATH®.
2 The VERSA-KATH
® is x-ray visible, and it is also steerable as long as rotation coincides with the advancement of the catheter.
The scarring triangle is located in-between the L5 DRG and the S1 nerve root and above the L5-S1 disc. Dense scarring can present clinically as: ipsilateral back pain (due to the dura and posterior longitudinal ligament adhering together), L5 radiculopathy, numbness and dysesthesia in the lateral calf to the lateral ankle and foot, and weakness on dorsal flexion of the foot. In advanced cases, foot drop may be evident. Opening of the scarring triangle with the recommended volumes can reverse these clinical symptoms. An S2 component will present as radiculopathy along the posterior aspect of the thigh and calf. Stretch-induced ischemia of the involved nerve roots is likely the cause of foot drop and can be reversed following the scarring triangle neuroplasty.