Role of Non-Real Time Imaging in Improving Success of Blind Inter-Laminar Epidural Injection for Treatment of Symptomatic Prolapsed Lumbar Inter-Vertebral Disc

One of the most commonly employed methods of treatment for Lumbar disc herniation with leg pain is epidural steroid injection. Of the three routes being deployed, inter-laminar approach is preferred as needle entry can be directed more closely to the assumed site of pathology, requiring less volume than the caudal route and it is less risky compared to the trans-foraminal approach. For effective placement of the spinal needle in the epidural space, use of C-arm is a must. But, the operation theatre and C-arm is not available in most of the health centers in the developing countries especially in rural settings. Time taken to set up is another issue. To improve the success rate of needle placement in “blind method” of ILESI, we have developed a technique of using digital X-ray of lumbo-sacral spine, which is available universally nowadays, to measure the depth of the epidural space and level of the targeted inter-vertebral space. Objective: To assess the effectiveness of measurements in plain roentgenograms of lumbo-sacral spine in guiding needle placement into epidural space. Methods: A prospective study was taken up in the Dept. of PMR, JNIMS during the period May 2017- Feb 2018. 56 consecutive clinically diagnosed prolapsed PIVD patients were enrolled. Lengths of spinous process and skin thickness were measured using a caliper. A 22G Quincke needle was advanced to the expected depth given by digital xray measurement. 1 ml of Iohexol dye was injected. Position of needle was checked by C-arm x-ray. Results: Out of the total 56 subjects, 46 (82.1%) completed the treatment program. Needle was placed at proper depth in 36 cases by using Xray measurement, giving success rate of 87.8%. Mean (SD) depth of epidural space from skin was found to be 3.82 (o.74) cm as measured from X-ray and actual measurement confirmed by fluoroscopy was 3.9 (0.81) cm (Pearson’s correlation coefficient =0.86). Conclusion: Measurement of depth of epidural space using plain X-ray of LS spine improves the success rate of blind MILESI from around 50% to 87.8%. This method of non-real time imaging is cost effective in developing countries where C-arm X-ray facilities are not available