Percutaneous endoscopic lumbar discectomy and interbody fusion with B-Twin expandable spinal spacer

Posterior lumbar interbody fusion (PLIF) is biomechanically sound as it ablates the degenerated disc, restores the intervertebral height, relieves foraminal stenosis, and positions the bone graft along the weight-bearing axis. But this conventional procedure also results in significant traction on the dural sac and the cauda equina and is thereby a potential source of neurologic damage. Therefore, we performed a minimally invasive technique: percutaneous endoscopic discectomy and interbody fusion (PEDIF) with B-Twin expandable spinal spacer (B-twin ESS) to treat symptomatic lumbar degenerative disc disease and explored the clinical outcome.

From June 2004 to December 2006, 43 consecutive patients with symptomatic lumbar degenerative disc disease were included in this study. There were 28 males and 15 females, with average age of 47 years (range 26-63). Following a routine micro-endoscopic discectomy or percutaneous nucleotomy, endplate curettage was meticulously carried out. The intervertebral space was packed with autograft cancellous bone cut from lumbar delivered through a 5-mm diameter funnel. The B-twin ESS was introduced into the intervertebral space and then expanded. Both stages were monitored by C-arm fluoroscopy.

The mean operative time was 110 ± 36 min (80-150). The mean blood loss was 350 ± 68 ml (210-700). The mean length of hospitalization was 6.6 ± 2.9 days (3-10). All patients were evaluated in follow-up of 12-30 months (mean 18). According to radiological evidence of fusion on dynamic X-ray plain film, 31 cases (72.1%) achieved bone graft fusion after 6 months postoperatively; at the final follow-up, union of the bone graft has been established in all but one patient (97.7%). The subsidence degree of the B-twin ESS was 20-30% in 2 cases and in rest of the cases less than 10%. According to the modified criteria of Chinese Orthopaedic Association, excellent in 31 cases, good in 8 cases, fair in 3 cases, poor in 1 case, and the rate of excellent and good cases was 91%.

The PEDIF technique provided an option for percutaneous interbody fusion similar to that in open surgery while minimizing destruction to adjacent tissues. This technique was safe and exhibited a trend toward decreased intraoperative blood loss, length of stay and the risk of neurological complications.