Extra-laminar microscopic-assisted percutaneous nucleotomy (EL-MAPN) for the treatment of foraminal lumbar disc prolapse, a modified minimally invasive approach

Abstract

In this work, a modification of the percutaneous surgical approach for removing the lumbar foraminal disc prolapse is introduced. A prospective study was performed. The indication for surgery was foraminal disc prolapse presenting with acute motor or persistent sensory radiculopathy. MRI and X-ray of the lumbar spine were performed. VAS and ODI were recorded. The operation was done under general anesthesia. A needle was inserted for level-localization using C-arm. A 1.5cm para-median skin incision was performed. A gradual dilatation using trocars was followed by the insertion of a tubular system. Under direct vision using the operative microscope, the lateral edge of the lamina was identified. A small, hooked probe was inserted in the foramen, and its position was documented fluoroscopically. With the help of the microscope, the triad consisting of Pedicle, Nerve root, and Prolapse "PNP" was identified. The nerve root was mobilized, and the prolapsed disc was removed. The study included 50 patients, 26 females, and 24 males. The mean follow-up was 18months. The mean operative time was 65min. The mean blood loss was 105ml. The mean VAS improved from 7.8 ± 2.3 preoperatively to 0.8 ± 0.3 after one year (p = 0.001). Mean ODI improved from 28 ± 10.4 to 4 ± 2.3 after one year (p = 0.02). A recurrent disc occurred in 2 patients and was revised in the same technique. EL-MAPN represents a minimally invasive approach for foraminal disc prolapse removal under direct visual control avoiding injury to the facet joint or pars interarticularis.