A Prospective, Multicenter Observational Study on MAST™ (Minimal Access Spinal Technologies) Fusion Procedures for the Treatment of the Degenerative Lumbar Spine

Instrumented lumbar fusion is usually done through an open procedure which involves an excessive intraoperative dissection and retraction of the paraspinal musculature leading, in a short term basis, to a prolonged recovery time from the surgery. This open approach is frequently associated with significant blood loss and need of transfusion, produces the majority of the perioperative pain, increases hospital stay and the chances of infection and delays the return to normal activities and to work. In a long term basis, the open procedure leads to denervation, atrophy and loss of the muscles independent function, resulting in an increased risk of "fusion disease", a term that has been coined to describe its occurrence. The minimally invasive spinal surgery was developed as a potential solution to the above-mentioned problems by reducing the amount of iatrogenic soft tissue injury while reaching the same traditional goals of the open procedures. Besides minimizing the long-term effects of exposure-related muscle injury, minimally invasive lumbar fusion techniques hold the promise of immediate short-term advantages. Patients undergoing minimally invasive procedures are reported to recover earlier from the surgery. Shorter time to first ambulation, less pain medication consumption, less blood loss, less required transfusion, shorter hospital stay and earlier return to work are generally associated with the minimally invasive procedure as compared to the standard open surgeries. The minimally invasive access requires a surgical corridor targeted on the disease which is accomplished by using a series of tubular muscle dilators allowing a clear intraoperative visualization to perform these procedures together with the parallel use of image guided percutaneous insertion of pedicle screws and instrumentation. The purpose of this study is to observe and document surgical practice and evaluate patients' outcomes following a MAST™ single or double level instrumented fusion procedure using PLIF or TLIF techniques for the treatment of the degenerative lumbar spine in a "real-world" patient population.