The Clinical Effect of i-FACTOR® Versus Allograft in Non-instrumented Posterolateral Spondylodesis Operation in the Elderly With Spinal Stenosis Due to Degenerative Spondylolisthesis

The average life expectancy in Denmark is increasing resulting in an increasing part of the population having age-related disease, ex lumbar spinal stenosis (LSS). LSS causes constriction of the nerves in the lumbar spine resulting in pain in the legs and lower back, especially when standing and walking, known as neurogenic claudication(Goh KJ FAU - Khalifa et al.). LSS occurs in a combination of degenerative changes in the lower back, including hypertrophy of the ligamentum flavus, arthrosis of the facet joints and bulging of the disc. Current treatment of LSS is varied ranging from non-operative conservative treatment to operation. Operative intervention shows very good results according to physical ability and pain(Christensen FB et al.;Hee HT and Wong;McGregor AH FAU - Hughes and Hughes;Xu et al.), but the most optimal treatment is still debated. Nevertheless, a decompression and, if needed, a spinal fusion is recommended.(Ausman). Clinical improvement including decrease of pain, improved ADL-function and an increased quality of life are parameters of highest interest and the purpose of an operation is clear: Making sufficient room for the affected nerves. In addition fusion is desired achieving stability avoiding a new compression of the nerves. Studies attending these issues find a correlation between fusion and clinical outcome, why obtained fusion of the affected levels are very important(Andersen et al.;Andersen et al.;Girardo et al.;Kornblum MB FAU - Fischgrund et al.). P-15, bound to Anorganisk Bone Mineral (ABM), called i-FACTOR®, shows fusion superiority, no side effects and no risk of transferring disease(Thorwarth et al. 5648-57;Thorwarth et al. 789-95;Wenz, Oesch, and Horst 1599-606;Scarano et al. 318-24;Kubler et al. 171-79) why the investigators find this material suited for fusion surgery in the elderly. To the investigators knowledge this is the first prospective study comparing fusion rates and postoperative clinic with i-FACTOR vs allograf