119 - The Sequential Transforaminal Allograft Cage (STAC) Technique. A Novel...

Oral Posters: MIS

Presented by: S. Mather - View Audio/Video Presentation (Members Only)


S. Mather(1), K. Perillo(1)

(1) Dupage Medical Group, Spine, Downers Grove, IL, United States


Minimally invasive lumbar fusion is an attractive method for lumbar fusion as it spares paraspinal muscle tissue and allows less pain in the postoperative period. However, determination of an actual solid fusion is often difficult to determine, even with CT. Typical MIS TLIF technique is one oblique cage placed centrally and accompanied by a variety of biologics, such as cancellous allograft or autograft with or without BMP. Our novel method of stacking 3 interbody blocks in the disk space triples the footprint of the structural interbody graft, avoiding possible subsidence, while maximizing biologically active surface area, and allows easy interpretation of post-op X-rays to assess fusion without CT. This method uses a modified tubular retractor, interbody preparation instruments, and novel cage with the insertion of commercially available corticocancellous allograft blocks to achieve a footprint 27 mm wide and 21-29 mm deep through a unilateral minimally invasive transforaminal approach. This technique will be demonstrated.

Methods: Thirty-three patients were followed prospectively. All had MIS TLIF using the STAC technique. 8 were 2-level and 25 were one level. BMP was not used in any patient. All but two patients had the 3-block stacked system; 2 patients had only 2 blocks (one cage and one allograft in one patient and the other patient with 2 allograft blocks), Patients were followed for a minimum of 6 months to assess fusion by standard AP and lateral X-ray. Assessment for fusion was done with Bridwell´s criteria. No dural tears , cage or allograft dislodgment, or neurologic complications occurred in any patient.

Conclusions: This STAC technique of MIS TLIF is a novel method which maximizes interbody footprint and biologically active surface area together to create a footprint similar to surface area of an ALIF with diameter 29 mm. This stability and ease of interpreting postoperative X-rays makes this method an attractive technique.