Conventional lumbar disc surgery as described in textbooks employs a midline incision 5 to 10 cm in length from the spinous process of L4 to S1 [2
]. The level of the iliac crest revelaed by the plain film of lumbar spine was used to determine the spinous process of L4 [3
]. The surgeon exposes the interspaces under direct vision so that no mistake is made while exploring the interspaces. The fascia, tendon and muscles are sacrificed in these procedures. The disc surgery itself involves decompression of the nerve root to relieve pain. If too much soft tissue and bone is damaged, post-operative pain is inevitable. Lumbodorsal fascia injury also leads to postoperative pain and can limit the back's range of motion postoperatively.
The micro lumbar disectomy was developed in order to minimize injury to the musculature of the back. An operative microscope is used for better visualization and special retractors and miniature instruments are used for the discectomy itself [4
]. Curettage of the disc space is not mandatory. The use of the microscope can lead to loss of three-dimensional visualization and introduces another potential source of operative field contamination. The preoperative localization of the surgical level is made with spinal needles [5
]. Two #20 gauze spinal needles are inserted perpendicularly to the skin approximately three-finger widths lateral to the spine, and lateral skin marker radiographs are then obtained. The skin incision is then made midline over the disc space. The paraspinous needles allow more accurate skin incision placement than a spinous process marker. The disadvantages are that spinal needle insertion may increase the risk of infection, and that it is a time-consuming procedure.
The arthroscopic micro discectomy was introduced by Kambin and colleagues [7
]. An 8 mm internal diameter cannula is introduced into the triangular working zone. Intraoperative fluoroscopic images are used to navigate the position of an oval cannula in these zones between the traversing and exiting nerve roots at the dorso-lateral aspect of the intervertebral disc. The percutaneous nuclectomy was described by Hijikata. In the procedures, the fluoroscopic image control is indispensable to confirm and document disc penetration and to watch the annulus cutter does not go too far to the other margin [9
]. The continuous exposure of theatre staff and the patient to x-ray radiation is the chief concern with this technique.
The miminal acess surgery for the anterior lumbar spine fusion described by Huang and colleagues [11
]. The techniques to localize the exact disc level was approached with the aid of C-arm intensified in an anteroposterior (AP) direction. Then an intersection point formed by the kirschner wire and the extension line of the anterior axillary line of the patient was marked. With this method, the need for radiologic check in a lateral direction was circumvented. The confirmation was obtained by a C-arm intensifier during the operation. Miccoli and colleagues developed minimally invasive video-assisted approach to the cervical spine. They inserted a 1-mm metal probe to exactly localize during fluoroscopy the vertebrae reached by the dissection for the anatomic-ragiologic study [12
]. In these procedures, the preoperative localization was performed by fluoroscopy and the exposure to radiation of surgeons and patients is inevitable.
The currently described procedure produces multiple parallel skin markers that correspond to the PA view of the patient positioned on the operating table. The patient needs to be placed evenly on the table to prevent differences arising with movement between the skin markers and interspaces of the lumbar spine. The intraoperative lateral radiograph is essential for confirmation of the level before laminectomy.