Study compares results of allograft and autograft bone use and measurement techniques

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According to a new study presented at the 30th Annual Meeting of the North American Spine Society (NASS; 14­­-16 October, Chicago, USA), spine surgeons should choose a patient’s own bone material rather than donor bone for better results in posterior atlantoaxial fusion.

“In an effort to reduce a patient’s pain and complication risk, surgeons have been relying more on allograft bone for spine fusion,” said Michael D Daubs, an orthopaedic surgeon and NASS Annual Meeting programme chair. “But, as this study indicates, not all bone is created equal, and the way surgeons have been measuring fusion success needs to be carefully re-examined.”

The study was selected as one of only 21 “Best Papers” at the NASS meeting. A record-breaking 1,180 scientific abstracts and session proposals were submitted this year. In this prospective comparative study, 41 consecutive patients underwent posterior atlantoaxial fusion with a screw-rod system fixation. After learning about the possible advantages and disadvantages of each, patients chose between allograft bone or their own bone, harvested from the iliac crest of their own pelvis.

Twenty-four chose allograft and 17 chose autograft. The patients were followed regularly, and underwent CT scans and dynamic radiographs every six months for at least 18 months. At the final follow-up, only two patients (8.3%) in the allograft group were confirmed with bony fusion based on CT image while 15 patients (88%) were confirmed with bony fusion based on CT image. However, all of the 41 patients showed “no movement” on dynamic radiographs, which some surgeons would say indicates that the vertebrae successfully fused. “This study indicates that not only is allograft unreliable for posterior atlantoaxial fusion, but we must be sceptical about using only dynamic radiographs to check fusion,” said Daubs. “We should focus energy on making autograft fusion safer and less painful for our patients.”