Outcomes of MI-TLIF in High Risk Patients Undergoing Fusion Using Cellular Bone Allograph: Analysis of Clinical Variables and Bone Fusion Rate

Introduction: MI-TLIF has demonstrable clinical benefits for patient by helping to preserve the normal anatomical integrity of the spine particularly in older and obese patients. Successful bone fusion is dependent on a variety of factors including bone graft material. A combination of drilled morselized autograft bone and cellular bone autograft (CBA) was used in this cohort of patients.

Methods: Fifty-one(51) patients underwent single or multi-level MI-TLIF, using a mixture of surgical site morselized autograft bone supplemented with CBA (Trinity ELITE). The primary outcome was successful fusion, defined by lack of motion based on independent radiographic assessment of flexion and extension films at 3, 6 and 12 months post-operatively and/or bridging bone at each treated level. Long-term patient reported outcomes (PRO) were also addressed.

Results: This study included 31 males (62%) with mean age of 66.4±3.7 years and mean BMI of 30.1±5.4. Oswestry Disability Index(ODI) improved significantly from 21.1±7.6 at baseline to 13.2±11.2 at 12 months(p=0.0024). VAS also improved from 7.4±2.4 to 1.9±2.7 at 12 months (p=0.0005). VAS left and right leg pain also demonstrated significant improvement from baseline scores of 4.0±3.5 and 6.6±3.0 to 0.2±0.6 and 0.9±2.0 (p=0.008 and < 0.001) respectively. At one-year, radiographic evidence of bone fusion was present in 49 patients (98%). No revision surgeries or implant-related adverse events were reported.

Conclusion : The combination of CBA along with surgical site morselized autograft in performing MI-TLIF afforded an excellent fusion rate and lowered postoperative complications. High risk individuals with advanced aged and increased BMI were adequately improved with this technique.