Contribution of recombinant human bone morphogenetic protein—2 to the rapid creation of interbody fusion when used in transforaminal lumbar interbody fusion: a preliminary report

Abstract

Object. The authors compared fusion rates in transforaminal lumbar interbody fusion (TLIFs) when using either autograft or bone morphogenetic protein (BMP) placed in the interbody space. Methods. Between September 2002 and December 2003, the authors performed 44 TLIF operations. Follow-up data were available for 40 patients. Of the 40 procedures, 19 involved cages filled with iliac crest autograft (Group 1) and 21 involved cages filled with a medium kit of recombinant human (rh) BMP-2 (Group 2). In all Group 2 patients, one BMP sponge was placed anterior to the cage and another was placed within the cage. In 12 of the Group 2 patients, iliac crest autograft was placed posterior to the BMP-filled cage (Group 2A). In the remaining nine Group 2 patients, only local autograft was placed posterior to the BMP-filled cage (Group 2B). Assessment of fusion was performed using dynamic radiography at 3-month intervals. Outcomes were assessed using the Prolo Scale, and iliac crest donor site pain was measured using a Visual Analog Scale (VAS). The mean follow-up period was 9 months (range 3–18 months). In Group 1 patients, one pseudarthrosis was detected. In Group 2 patients, dynamic radiography demonstrated solid fusion in all patients except one in Group 2B. Fiftyeight percent of patients in whom iliac crest autograft was used complained of donor site pain 6 months after surgery (5 of 10 points on the VAS). Symptomatic foraminal bone formation was not observed in any Group 2 patient. Conclusions. The use of rhBMP-2 is safe in TLIFs when the sponges are placed away from the dura mater, and BMP promotes a more rapid fusion than iliac crest autograft alone. The use of rhBMP-2 in combination with local autograft is an excellent option for promoting solid fusion with TLIF, and it eliminates the possibility of iliac donor site pain.