An alternative to automated percutaneous suction discectomy is arthroscopic percutaneous lumbar discectomy developed by Kambin . Like the advocates of chemonucleolysis and suction discectomy, he notes the potential benefits include the avoidance of perineural fibrosis, reduction in the potential for instability, and perhaps avoidance of nuclear reherniation through an annulotomy site. He has developed an array of arthroscopic instrumentation that is used to access the spine through a posterolateral approach.
Similar to others, he advocates that the procedure be done for radicular pain that is greater than back pain, accompanied by positive tension signs, a correlating imaging study, a failure to respond to adequate conservative management, and the absence of drug abuse and psychosocial disorders. He also notes that the procedure is contraindicated in patients with any element of spinal stenosis, particularly in the lateral recess, a migrated disc fragment, or caudal symptoms.
The technique is based on a triangular working zone, as depicted in Figure 4. The procedure is done with the patient awake or minimally sedated. An 18-gauge needle is inserted at a distance of 8 to 11 cm lateral to the midline unless the patient is obese, in which case the needle is inserted more laterally. The position of the needle is checked fluoroscopically.
The stylet of the needle is then withdrawn and replaced by a guidewire. A small skin incision is made, and a cannulated obturator, which serves as the passageway for instruments, is placed over the guidewire and advanced toward the disc. When the cannulated obturator is near the disc, the guidewire is removed, and the obturator is advanced to the annulus, which usually reproduces the patients symptoms. An access cannula with an outer diameter of 6.4 mm is passed over the cannulated obturator, which is the object through which the instruments are placed. Confirmation of the proper placement is obtained in anteroposterior and lateral fluoroscopic views. Kambin emphasizes the importance of arthroscopically visualizing the periannular structures before the annulus is trephined. Once the annulus is trephined, the arthroscope is again used to visualize the intradiscal position. Specially constructed forceps are then used to remove nuclear fragments . As an alternative, a bilateral biportal approach may be used, which permits continued arthroscopic inspection as the nucleus is débrided.
It appears, based on a 20-year experience, that percutaneous lumbar discectomy is clinically efficacious, although this view has not been tested by rigorous randomized prospective evaluation. It is of interest that the return to work for patients with no compensation is 92 days, whereas for those with compensation, it is 262 days. This is no better than the time from conventional discectomy. Why has the procedure not gained greater popularity? One can speculate that there are a number of reasons. In particular, Kambins criteria for selection are significantly narrower than those used for conventional lumbar discectomy (e.g., the absence of any element of lateral recess stenosis), and the procedure appears to have a significant learning curve.
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