Low fusion rate after L5-S1 laparoscopic anterior lumbar interbody fusion using twin stand-alone carbon fiber cages.

STUDY DESIGN: Prospective study of a cohort of patients who underwent L5-S1 laparoscopic anterior lumbar interbody fusion.

OBJECTIVES: To assess the fusion rate and the clinical outcome more than 2 years after L5-S1 laparoscopic anterior lumbar interbody fusion using twin stand-alone carbon-fiber cages.

SUMMARY OF BACKGROUND DATA: The first reports on laparoscopic anterior lumbar interbody fusion using stand-alone cages appeared in 1995. Since then several articles have reported contradictory data regarding fusion rate. There are no publications describing the fusion rate of stand-alone lumbar carbon-fiber cages.

METHODS: The authors evaluated 12 patients (mean age 36.5 years) in whom endoscopic L5-S1 anterior lumbar interbody fusion was performed using twin stand-alone laparoscopic carbon-fiber cages. Clinical evaluation was carried out prospectively by the use of three self-evaluation scales. Radiologic evaluation was performed by an independent radiologist using dynamic flexion-extension films and CT scans at 6 and 12 months after surgery and subsequently every year until fusion was demonstrated.

RESULTS: After a mean follow-up of 36.6 months (range 24-63 months) the clinical condition of the patients was significantly better than their preoperative status: visual analog scale (P < 0.01), Prolo score (P < 0.05), and Waddell Disability Index (P < 0.01). L5-S1 mobility did not exceed 5 degrees in any dynamic study. However, the overall CT scan fusion rate at 2 years of follow-up was 16.6%. Three years after surgery, CT demonstrated fusion in one of five patients.

CONCLUSION: Two years after endoscopic L5-S1 anterior lumbar interbody fusion using twin stand-alone laparoscopic carbon-fiber cages, the fusion rate was unacceptably low. However, the clinical outcomes of these patients were significantly improved compared with their preoperative status.