The use of autogenous bone graft in spinal fusion is progressively declining. Different allografts including the human bone morphogenetic protein have been proposed to facilitate fusion rates but are associated with various adverse effects. Osteocel belongs to a new class of allograft tissue material that is a re-absorbable biomaterial with allogenic mesenchymal stem cells. The purpose of the present retrospective study was to analyze the clinical effectiveness of mesenchymal stem cells allograft (Osteocel") to achieve radiological arthrodesis in adult patients undergoing lumbar interbody fusion surgery for different indications. Fifty-two consecutive patients received lumbar interbody fusion at one (69%) or two contiguous (31%) levels of lumbar spine for various indications. The mean age was 50 (range, 27 to 77) years; 60% were females; 43% were habitual smokers and 21% had previously failed surgery at the index level(s).
Outcome measures: Radiographic analyses of fusion by plain films and CT scans. Procedures performed were circumferential fusion (67%), ALIF (17%) and TLIF (16%). Followup radiographic data was analyzed to establish arthrodesis versus failure (pseudarthrosis), number of months until achievement of fusion, and possible factors affecting the fusion rate. Followup ranged from 8 to 27 (median, 14) months. Solid arthrodesis was achieved in 92.3% of patients at median followup time of 5 months (95% Cl; range, 3 to 11 months). Kaplan-Meier survival curves and Mantle-Cox test were conducted to assess the effect of various factors on the rate of fusion. Statistics showed that increasing age (older than 50 years) (p = 0.017) and habitual smoking (p = 0.015) delayed the fusion time and increased the risk of pseudarthrosis. The use of Osteocel allograft is safe and effective in adult patients undergoing lumbar interbody spinal fusion procedure. Increased age and habitual smoking delays fusion but gender, previous surgery at the index level, type of procedure and number of levels do not affect the fusion rates.