There are two main types of L4-L5 fusion procedures that can be performed to treat degenerative conditions affecting the fourth and fifth lumbar vertebrae: minimally invasive fusion and open back fusion. These fusion procedures have similar goals of relieving neural compression and restoring stability to the L4-L5 lumbar motion segment in the lower back, but each takes a different surgical approach.
Open Back Fusion
Open back fusion performed on the L4-L5 vertebral junction is a highly invasive operation, requiring a surgeon to make large incisions and dissect spinal muscles to access the spine. Decompression of the spinal cord or nerve roots often occurs next, with the removal of bone spurs, portions of calcified ligaments or other anatomical abnormalities placing pressure on the delicate neural structures. The L4-L5 intervertebral disc is removed entirely and a supportive cage is situated in the empty disc space and packed with bone graft material. Bulky hardware (rods, plates and screws) is used to affix the two vertebrae. Due to the invasive nature of open back fusion, patients undergoing this type of surgery must be hospitalized and often face a lengthy and arduous recovery.
Minimally Invasive Fusion
While minimally invasive L4-L5 fusion procedures, in essence, follow the same steps as open back fusions, the major difference (and advantage) is the minimally invasive surgical approach employed. The procedure requires only small incisions through which a surgeon can perform the entire procedure. The surgeon will push aside muscle fibers without the need for muscle dissection. Neural decompression, removal of the disc in between the vertebrae, and placement of a supportive implant are completed. Bone graft material and a concentration of a patient’s own stem cells are packed around the implant and small rods and screws are used to hold the L4-L5 vertebrae together while the vertebrae grow, or “fuse” into one solid segment of bone.
Because minimally invasive L4-L5 fusion procedures are performed on an outpatient basis, hospitalization is not required. Additionally, the lack of muscle dissection required during a minimally invasive fusion procedure allows a patient to enjoy a much faster and less arduous recovery period as compared to the recovery associated with open back fusions.