Abstract
Introduction
It had been previously shown that minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) has similar fusion rates and complication rates compared with open TLIF surgery. Different graft materials are being used for fusion. However, no previous studies have compared the fusion rates of different graft materials. The aim of this study was to compare the fusion rates of different graft materials used in MIS TLIF, via meta-analysis of the published literature.
Materials and Methods
A MEDLINE search was performed to identify the studies reporting fusion rates of MIS TLIF using different graft materials. A database was created which included patient demographics, preoperative data, type of graft material, clinical outcome, fusion rate, and duration of follow-up. Groups were defined based on the type of graft used. Meta-analysis of the fusion rate was performed using the StatsDirect statistical software.
Results
Forty series with a total of 1,320 patients were included. Age and gender distribution were homogeneous in almost all series. The most frequently operated level was L4/L5. Implanted cages were made of PEEK, titanium, or Hydrosorb. Significant clinical improvement was observed in all studies. Fusion rates were high, regardless of the type of the graft, ranging from 92 to 99% with different graft materials. Comparison of all rhBMP series with all non-rhBMP series showed fusion rates of 96.6 versus 92.5%, respectively. Iliac bone graft alone compared with non-Iliac bone graft showed fusion rates of 92.8 and 92.4%, respectively. The lowest fusion rate was observed with an isolated use of autologous local bone (91.7%). However, the addition of rhBMP to local bone increased the fusion rate up to 95% and the addition of non-rhBMP grafts to the local bone increased it up to 93%. The median complication rate was 8.82%, varying between 0 and 35.71%.
Conclusion
Utilization of rhBMP for MIS TLIF resulted in high fusion rates. Isolated use of local bone resulted in the lowest fusion rate. Addition of non-rhBMP grafts to local bone increased the fusion rate moderately, and addition of rhBMP was associated with a higher increase. Given the potential complications of iliac bone harvesting and rhBMP, the decision on the type of graft material should be made separately for each patient, based on specific characteristics. When rhBMP is used, efforts should be made to use the lowest possible amount.