Injection therapy is a major component of conservative management for spinal disorders like herniated nucleus pulposus (HNP) and spinal stenosis. The most common problem faced during the injection – transforaminal, interlaminar or caudal epidural block is delivering the drug at the exact site of lesion due to adhesions more so when there has been a previous open spinal surgery. Conventional neurolysis effect was limited because adhesiolysis and drug delivery were in the posterior epidural space. So, we report a simple neurolysis technique which can inject drugs directly to nerve roots and intervertebral discs at anterior epidural space through the caudal approach using conventional neurolysis devices.

Purpose
We planned this study to comparatively analyse several clinical results depending on the range of incision in herniated nucleus pulposus surgery.
Materials and Methods
We examined 49 cases herniated nucleus pulposus , performed laminectomy or discectomy from 2006.1 to 2007.2. Average age of patients was 44 years (19~73), male 25 cases and female 24 cases. 20 cases (9 male, 11 female) of conventional incision, and 17 cases (7 male, 10 female) of mini incision, 12 cases (9 male, 3 female) of microscopically assisted percutaneous nucleotomy (MAPN) were performed. All cases were protruded or extruded nucleus pulposus at L4-5 single level. Used VAS score to compare the pain after the operation with preop pain, checked ODI (Oswestry disability index) to compare the functional recovery of the ordinary activities, blood loss measured by total amount collected by drainage tube. Degrees of inflammation were compared by CRP of 1st, 7th, 14th day after the surgery.
Results
Conventional incision (Group I) took average 71 minutes of operation time, degree of pain relief was 7.8→3.2, average ODI was 61%, average blood loss was 69 ml and average change in CRP was 2.5→.2.2→2.0. In mini incision (Group II), 55 minutes, 7.3→2.47, 44%, 45 ml, 2.0→1.7→0.3 and , in cases with MAPN (Group III), 71 minutes, 7.1→2.41, 48%, 19 ml, 1.6→1.1→0.4. Operation time was similar on group I and group III and took shorter on group II. Amount of pain relief showed significant change in group II and group III, indicating that these were much greater than group I. ODI was delayed in group I. Average blood loss decreased significantly in group III. CRP level increased on first day after the operation, group II and group III showed more decrease level of CRP comparing to group I as time flows.
Conclusion
By comparing 3 groups, group III and group II were of better result in average ODI a, blood loss and CRP change. But, MAPN has long learning curve and longer operation time, so we recommend mini incision method in this study.