[Development of percutaneous endoscopic approach for lumbar disc herniations].

"Primum nil nocere" (minimally invasive procedure) has been the perennial pursuit for surgeons since the time of Hippocrates. However, due to the recent advancement of optical technology and the development of related devices, a remarkable progress has been made in lumbar discectomy by using minimally invasive surgery. By minimizing not only skin incision but also approach related morbidity, an adverse effect to the nerve root can be reduced to the minimum. And day surgery (outpatient surgery, same day surgery, ambulatory surgery) hastens patients' return to normal life. In the U.S., outpatient surgery has grown in popularity since Medicare's introduction of prospective payment system of in-hospital treatment in 1983. As for lumbar disc surgery, a surgical technique which is applicable to the disc herniation at a high location or a traverse section has been developed. This procedure is conducted under either local or general anaesthesia and designed to take the pressure off the nerve root by directly excising the disc that is pushing against the nerve root. The surgery can be done on an outpatient basis or with one overnight stay in the hospital, and most patients can be released from the hospital within 24 hours. This is a technique called percutaneous endoscopic lumbar discectomy (PELD) and the disc can be dissected from lateral intervertebral foramen or between the interlaminar window of vertebrae. PELD originated from percutaneous nucleotomy devised by Hijikata et al. in 1975 and the introduction of endoscopic technique has enabled the direct approach to the lumbar disc herniation, located further posteriorly than nucleus pulposus. It is not an exaggeration to say that this technique was created in Japan. Minimal damage to posterior longitudinal ligament and bones would reduce the postsurgical instability. The procedure is also advantageous in preventing lumbar facet syndrome and vertebral canal stenosis. The patients' satisfaction rate is high in terms of postoperative recovery and the usage of NSAID, and compared to microscopic discectomy and MED technique, PELD can be considered as less invasive surgical technique for lumbar disc herniation. This technique makes the most of the space within the intervertebral foramen where, as Kambin claimed, the safe approach to the lesion is possible. As we make the skin incision more medially than reported before in order to approach the intervertebral foramen at a steep angle, the occurrence of exiting nerve lesion at a superior location has decreased. This surgical method would be a promising alternative to MED technique as well as microscope-assisted technique.