Minimal Invasive Transforaminal Lumbar Interbody Fusion (TLIF): Technical Feasibility and Early Results
Posted on: 12/02/2004
James D. Schwender, Kevin T. Foley, David P. Rouben
Introduction: Transforaminal lumbar interbody fusion (TLIF) continues to gain popularity as one of the treatments of choice for lumbar spine fusion. This technique often obviates the need for anterior exposure to the lumbar spine to obtain circumferential fusion while providing direct decompression of the neural elements. Advances in technology allow for the TLIF technique to be performed in a less invasive fashion maintaining the advantages of the TLIF concept.
Methods: The METRx™ system (Medtronic Sofamor Danek) is used unilaterally though a 22 or 26mm working cannula for exposure of the facet joint. Unilateral facetectomy is performed to expose the disc space through the foramen. Sub-total discectomy is carried out through the cannula unilaterally. Structural support is achieved with either allograft bone or Harm’s type cages. Bone grafting is achieved with either local autologous or allograft bone and in some cases augmented with recombinant bone morphogenetic protein-2. If indicated, the contralateral facet and posterior elements are packed with bone graft through a second cannula. No autologous bone graft harvesting is required. Bilateral percutaneous pedicle screw placement is accomplished with the Sextant™ pedicle screw system (Medtronic Sofamor Danek).
Results: The results of the first consecutive 49 patients, October 2001 through August 2002, with a minimum of six months follow-up were analyzed. The index diagnosis was degenerative disc disease with recurrent HNP in 26, spondylolisthesis in 22 and one patient with a Chance type seat-belt fracture. The majority of cases (n=45) were at either L4-5 or L5-S1. There were no intra-operative complications that required conversion to open surgery. Pedicle screws were placed bilaterally in all cases. Operative time averaged 240 minutes (range 110-310). Estimated blood loss averaged 140 cc (range 50 to 450). The average length of stay was 1.9 days (range 1-4 days). All patients (n=45) presenting with pre-operative radiculopathy had resolution of symptoms post-operatively. Complications included two cases of new radiculopathy from screw mal-position requiring second procedure screw redirection, and two other cases of radiculopathy; one patient from graft dislodgement and the other secondary to contralateral neural foraminal stenosis. Narcotic use was discontinued, on average, between two and four weeks postoperatively. Outcomes and radiographic data are in the process of being collected. No early failures or other complications have been documented.
Discussion: The early results of this novel technique are encouraging. Preoperative radicular symptoms resolved in all cases with a relatively low complication rate. Length of stay averaged 2 days and blood loss less than 150 cc. Post-operative pain diminished rapidly over the first several weeks.
Conclusions: Minimally invasive transforaminal lumbar interbody fusion is a technically feasible method that allows for percutaneous neural decompression and interbody bone grafting. Although technically demanding, this procedure offers several advantages over traditional open techniques. These include minimizing soft tissue trauma, minimizing blood loss, shortening hospital stays, no iliac crest bone harvesting, and the potential for earlier return to function. Further analysis will be required to determine rates of fusion and long-term outcomes.
