OBJECTIVETo prospectively evaluate the clinical effects of posterior paramedian approach in nerve root decompression and reducing muscle damage in low back surgeries.

METHODSStudy group included 30 cases treated from January 2007 to May 2008, DDD 8 cases, spondylolisthesis 6 cases, LDH 11 cases, Low back surgery failure re-operation 5 cases. Based on the comprehensive understanding of modern spine anatomy, we abandoned laminectomy in our procedure, applied a mid-waist skin incision, dissect to the paraspinal muscles where you could easily reach the facets by separating between the multifidus and longissimus, enlarge the canal by performing resection along ligamentum flavum and the inner broader of the articular process, remove enough tissue till you could expose the traversing root and the disc space, this method could achieve a limited but precise and effective decompression with not taking out all of the articular process. Once the anatomy mark of the pedicle is located (usually would be at the central area of the incision), pedicle screws placement would be precise and easy without struggling with muscle traction. The following procedures would be Spondylolisthesis reduction, discectomy and interbody fusion.

RESULTSPost-op patients of study group all showed significant improvement of pain symptoms, VAS reduced from 7.14 + or - 1.8, pre-op to 1.39 + or - 0.72 post-op, narrowed disc space regained height, spondylolisthesis reached anatomic reduction, no complications such as pedicle screw misplacement and nerve root damage were found, the lumbar spine regained it's physiological lordosis structure. Significant difference is discovered (P < 0.001) in statistic study concerning the rate of intractable low back pain between pre-op and post-op.

CONCLUSIONSApplying low back surgery through posterior para-median approach could directly reach the inferior/superior facets and the "soft" structures of the spinal canal, expose the exact decompression region and anatomy mark of the pedicle in the central surgical field without strong retraction on the para-spinal muscles. This approach has the advantage of lowering the surgical difficulty of implantation, reducing the risk of nerve damage and is also a minimum invasive procedure. In many cases, laminectomy is unnecessary, leaving the lamina intact could preserve the physiological anatomy of the spine.