Percutaneous Lumbar Diskectomy Using a New Aspiration Probe

Abstract

The introduction of chymopapain and chemonucleolysis raised hopes that a relatively noninvasive treatment for her­ niated lumbar disk had been developed. However, injection of chymopapain into the lumbar nucleus pulposus is not an innocuous procedure. Hypersensitivity to the drug is a major problem; the current anaphylaxis rate is estimated to be about 1% and even higher among women patients [1]. Recent reports of transverse myelitis and subsequent paraplegia associated with chymopapain injection have raised serious questions about its use in young and otherwise healthy persons. Percutaneous lumbar diskectomy has been offered as a relatively noninvasive means of disk decompression involving removal of the disk by mechanical rather than enzymatic action. Previous attempts at percutaneous diskectomy, al­ though yielding preliminary results comparable to those of chymopapain, have required insertion of relatively large can­ nulas (~ 6 mm diam) into the disk space, which has raised concern about possible nerve injury on introduction of the cannula [2-4]. In addition, the disk material had to be removed with a modified pituitary forceps, which was tedious and time­ consuming. For these reasons, acceptance of the procedure has been slow. We report a percutaneous diskectomy using a new auto­ mated disk-aspiration probe. The probe's small size (2 mm diam) minimizes the risk of nerve root injury while its auto­ mated action allows rapid removal of disk material. Technique The patient is placed in the right lateral decutibus position . Using fluoroscopy, a lateral view of the patient's spine is obtained and the L4-L5 disk interspace identified. An entry point for the probe is selected on the skin about 10 cm from the midline as identified by the spinous processes. The patient is then prepped, draped, and given local anesthesia. A 25cm-Iong, 18-gauge hubless stainless steel sheath with a central trocar is aimed obliquely toward the posterior margin of the intervertebral disk as seen on the lateral view. The patient is monitored continously. If he experiences radicular pain, the sheath is redirected . When the sheath is correctly positioned against the disk in the lateral view, its position is confirmed in the anteroposterior view. The trocar is then removed, and a 2.5-mm cannula with an inner blunt-ended sleeve is placed over the hubless sheath . This cannula and sleeve are advanced to the disk while the patient is again monitored for radicular pain . When the cannula appears to be in the correct position, the sleeve and 18-gauge hubless sheath are removed, leaving the 2.5-mm cannula against the anulus of the disk. A 22-gauge needle is then inserted into the center of the disk through the large cannula to confirm that the trajectory of the cannula will bring the final instrument into the center of the disk. The needle is removed, and a hole