To evaluate the early clinical results of lumbar microdiscectomy using minimally invasive tubular retractor (METRx-MD system, Medtronic Sofamor Danek, Memphis, TN), and to validate the merits of minimally invasive spinal surgery.

From April, 2003 to April 2004 we retrospectively studied a consecutive series of 45 patients who underwent lumbar microdiscectomy using minimally invasive tubular retractor. In all cases, minimally invasive approach using the tubular retractor were performed with a 2 cm sized paramedian incision. The following data were collected: clinical outcomes, operative time, intraoperative blood loss, need for blood replacement, time needed before ambulation, length of hospital stay, and complications. The clinical outcomes were assessed by the modified MacNab criteria.

Minimally invasive tubular microdiscectomy was performed in 45 patients over a 12-month period with an average follow-up of approximately 8 months. The clinical outcomes assessed by MacNab criteria were excellent in 33 patients (73%), good in 10 patients (22%). The average operative time was 63 minutes (range, 35 to 95 minutes). The average blood loss was 62 mL (range, 50 to 110 mL). None of the patients needed blood replacement. With the exception of 2 patients, all patients could walk at the day of surgery. The average hospital stay was 2.3 days. None of the patients had dural tear, wound problem, or other complications.

Lumbar microdiscectomy using tubular retractor can offer a useful modality for the treatment of lumbar herniated disc with the merits of minimally invasive spinal surgery. Further long-term, randomized, prospective investigations are needed to fully evaluate the impact of this technique.