ABSTRACT
The authors retrospectively analized the radiographs and medical records of 135 consecutive patients who underwent minimaly invasive spinal surgery from January, 1990 to December, 1994 at our institution. Among these, 72 patients have had chemonucleolysis and others percutaneous automated lumbar discectomy(PALD). The success rate was similar in both groups, ie, 75% in chemonucleolysis and 74.6% in PALD by Macnab's criteria. The higher success rate could be obtained in 1) younger age below 30, 2) predominant sciatica than lower back pain, 3) eccentric bulged disc with minimal degeneration, 4) abscent or minimal neurologic deficits. In conclusion, provided patients are carefully screened, minimal invasive spinal surgery is more preferable over conventional surgery, providing a safe and effective therapeutic alternative to many patients suffering from herniated lumbar disc.