Iliac Crest Bone Graft Donor Site Pain After Anterior Lumbar Interbody Fusion

Abstract

Autogenous iliac crest bone is the gold-standard graft for spinal fusion surgery. Unfortunately, there is a frequent incidence of graft site pain that persists well into the postoperative period with complication rates reported in 2.8-39% of patients. Persistent pain lasting at least 2 years is reported in 15-39% of patients. The objective of this work was to determine the incidence of acute and persistent pain as well as patient assessment of graft site appearance following iliac crest bone graft harvest for anterior lumbar interbody fusion (ALIF). The control arms of four randomized prospective multicenter clinical trials evaluating recombinant human bone morphogenetic protein-2 (rhBMP-2) versus autogenous iliac crest bone graft were combined. Two hundred eight patients underwent iliac crest bone graft harvest for ALIF in threaded cylindrical cages or threaded bone dowels. Patients were assessed at each postoperative visit with questionnaires evaluating graft site pain intensity, duration, and appearance. Two hundred eight patients underwent iliac crest bone graft harvest for ALIF as the control group of four randomized prospective multicenter clinical trials evaluating rhBMP-2 versus autogenous iliac crest bone graft in threaded cylindrical cages or threaded bone dowels. Most patients in the control group had anterior iliac crest graft harvest, equally from the right and left side. Three grafts (1.4%) were taken from the posterior crest and six (2.9%) were tricortical. Follow-up was obtained at hospital discharge, 6 weeks, 3, 6, 12, and 24 months. A pain evaluation score was made up of two Visual Analog Scales: one scale measuring intensity, the other frequency of pain. For the intensity scale, a rating of "0" meant no pain and "10" was "as bad as it could be." For the frequency scale, a rating of "0" meant pain was present "none of the time" and "10" meant it was present "all the time." Combining these scales, a total score of 20 indicated the worst pain was present all the time. Patients were also questioned about the graft site appearance. Two hundred eight patients underwent iliac crest harvest, and prospective data were available on 202 patients. At hospital discharge, 2 patients (1%) had no pain; this increased to 34 of 199 (17%) at 6 weeks postoperatively and to 85 of 199 patients (43%) at 3 months. However, 41% of patients reported pain at 6 months postoperatively (79/192), and 33% of 168 reported pain at 1 year. One hundred forty-one of 208 patients completed a survey at 24 months, with 31% reporting some level of pain. At hospital discharge, the graft site pain score ranged from 0 to 20 with a mean of 12.8, decreasing to 7.3 at 6 weeks, to 3.8 at 3 months, and to 2.9, 2.4, and 1.8 at 6, 12, and 24 months, respectively. At all time intervals, P values from t tests comparing the mean with 0 were <0.001. Graft site appearance at discharge was good in 49% of patients, fair in 40%, and poor in 11%. At 6 weeks, appearance was good in 69%, fair in 27%, and poor in 5%; at 3 months, it was good in 75%, fair in 24%, and poor in 2%; at 6 months, it was good in 82%, fair in 15%, and poor in 3%; at 12 months, it was good in 82% and fair or poor in 19%; and at 24 months, it was good in 84% and fair or poor in 16%. There was no significant difference between posterior and anterior harvest sites or bicortical grafts, and all were included in the analysis. Right or left side demonstrated no differences. This is the first study known to the authors presenting results of prospective data collected in a multicenter study evaluating iliac crest harvest site pain, both intensity and frequency, as well as graft site appearance. The results demonstrate that 31% of patients had persistent pain at 24 months postoperatively and 16% reported fair or poor appearance of their graft site. Persistent donor site pain remains a problem with harvest of autogenous iliac crest bone graft for spinal fusion. This prospective study, the first such study reported for ALIF, confirms that donor site pain remains a significant postoperative management problem.