Mroz TE, Wang JC, Hashimoto R, Norvell DC.: “Complications related to osteobiologics use in spine surgery: a systematic review.” Spine, 35(9 Suppl): S86-104, 2010

STUDY DESIGN: Systematic review. OBJECTIVE: The objectives of this systematic review were to identify the character and rates of complications in patients after the use of BMP in spine fusion surgery and to determine whether there is a dose-response relationship of BMP with complications. SUMMARY OF BACKGROUND DATA: BMP is used on-label for ALIF with LT-CAGE and off-label for various spine fusion applications in the cervical, thoracic, and lumbar spines because of its effectiveness in promoting arthrodesis. Multiple studies published over the past several years have highlighted complications associated with BMP in a variety of clinical fusion scenarios. There are no systematic reviews on this topic, and thus, the complication profile of off-label use or physician directed use of BMP in spinal fusion surgery is not well characterized. Some of the reported complications are unique to BMP, which underscores the need for this thorough literature review. METHODS: A systematic review of the English language literature was performed for articles published between 1990 and June 2009. Electronic databases and reference lists of key articles were searched to identify articles examining the use of BMP in spine surgery. Two independent reviewers assessed the level of evidence using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) criteria and disagreements were resolved by consensus. RESULTS: Two hundred forty-‘ articles that assessed outcomes after BMP use in spinal surgery were identified from the literature; of these, 31 articles were selected for inclusion. We determined that multiple complications are associated after the use of rhBMP-2 in both cervical and lumbar spine fusion surgery. There is a mean incidence of 44%, 25%, and 27% of resorption, subsidence, and interbody cage migration reported for lumbar spine interbody fusion surgery although reoperation or long-term detrimental effect was rare. Cervical studies report a mean 5.8% of postoperative soft tissue problems, including dysphagia, when rhBMP-2 is used for ventral cervical fusion. It was determined that the strength of evidence of the peer-reviewed literature that report on types of complications is high for the lumbar and low for the cervical spine, respectively, and that the current strength of evidence on rates of complications with BMP is moderate and low, respectively. CONCLUSION: The complication profile of BMP-2 for ALIF with LT-CAGE is well characterized. Because of the lack of substantive data, the same is not true for other types of lumbar fusions, or for cervical or thoracic fusion applications. BMP has been associated with a variety of unique complications in the ventral cervical and lumbar spines. The published data on BMP fail to precisely profile this product’s use in fusion surgery; hence, it should be used only after a careful consideration of the relevant data. Well-designed and executed studies are necessary to completely define the incidence of various complications relative to type of BMP, type and region of fusion, surgical technique, dose, and carrier, and importantly, to define the natural history and management of associated complications.

Hillard VH, Fassett DR, Finn MA, Apfelbaum RI.: “Use of allograft bone for posterior C1-2 fusion.” J Neurosurg Spine, 11(4): 396-401, 2009

OBJECT: An iliac crest autograft is the gold standard for bone grafting in posterior atlantoaxial arthrodesis but can be associated with significant donor-site morbidity. Conversely, an allograft has historically performed suboptimally for atlantoaxial arthrodesis as an onlay graft. The authors have modified a bone grafting technique to allow placement of a bicortical iliac crest allograft in an interpositional manner, and they evaluated it as an alternative to an autograft in posterior atlantoaxial arthrodesis.
METHODS: The records of 89 consecutive patients in whom C1-2 arthrodesis was performed between 2001 and 2005 were reviewed.
RESULTS: Forty-seven patients underwent 48 atlantoaxial arthrodeses with an allograft (mean follow-up 16.1 months, range 0-49 months), and 42 patients underwent autograft bone grafting (mean follow-up 17.6 months, range 0-61.0 months). The operative time was 50 minutes shorter in the allograft (mean 184 minutes, range 106-328 minutes) than in the autograft procedure (mean 234 minutes, range 154-358 minutes), and the estimated blood loss was 50% lower in the allograft group than in the autograft group (mean 103 ml [range 30-200 ml] vs mean 206 ml [range 50-400 ml], respectively). Bone incorporation was initially slower in the allograft than in the autograft group but equalized by 12 months postprocedure. The respective fusion rates after 24 months were 96.7 and 88.9% for autografts and allografts. Complications at the donor site occurred in 16.7% of the autograft patients, including 1 pelvic fracture, 1 retained sponge, 1 infection, 2 hernias requiring repair, 2 hematomas, and persistent pain.
CONCLUSIONS: The authors describe a technique for interpositional bone grafting between C-1 and C-2 that allows for the use of an allograft with excellent fusion results. This technique reduced the operative time and blood loss and eliminated donor-site morbidity.

Mikhael MM, Huddleston PM, Nassr A.: “Postoperative culture positive surgical site infections after the use of irradiated allograft, nonirradiated allograft, or autograft for spinal fusion.” Spine, 34(22): 2466-8, 2009

STUDY DESIGN: Retrospective chart review.
OBJECTIVE: We report the rate of postoperative infection at our institution following the use of irradiated allograft, nonirradiated allograft, or autograft for spinal fusion procedures.
SUMMARY OF BACKGROUND DATA: Infection after a spinal fusion procedure is a devastating complication. It has not been defined whether spine bone graft preparation has any correlation with postoperative infection in spinal fusion procedures.
METHODS: We retrospectively identified 1435 patients who underwent spine fusion procedures with a minimum 1-year follow-up. Irradiated allograft was used in 144 patients, nonirradiated allograft was used in 441 patients, and autograft was used in 850 patients. Postoperative spinal infection was based on documented positive spine cultures at the time of re-exploration for presumed infection. Infection rates were estimated using the method of Kaplan and Meier; estimates were calculated out to 1-year postsurgery, and rates were compared using log-rank tests.
RESULTS: No significant difference in the rate of surgical site infection at 1 year was observed after the use of irradiated allograft (1.7%), nonirradiated allograft (3.2%), or autograft (4.3%), P = 0.51.
CONCLUSION: There is no significant difference in the rate of infection following spine fusion using irradiated allograft, nonirradiated allograft, or autograft. The selection of bone graft to aid in spinal fusion should be based on the requirements of surgical technique and availability of the desired tissue and not on a perceived association with postoperative infection.