Anterior Lumbar Interbody Fusion Surgery
Anterior lumbar decompression surgery is a surgical technique used to fuse the adjacent vertebrae from the spine’s front. The fusion surgery involves removing the disc material and inserting a bone graft and a cage (implant) to join the vertebrae naturally. The anterior lumbar interbody fusion may be used alone or in conjunction with the posterior approach to provide more stability.
The fusion surgery eliminates any motion in between the involved segment and thus provides stability. The surgery also involves removing the intervertebral disc and any other bony or soft tissue structure compressing the neural structures. The fusion construct is usually stabilized with a metal plate and screws from the front or screws and rods from the back.
The anterior approach may be used in patients with traumatic conditions such as herniated intervertebral discs, traumatic anterior extradural compression, etc. The approach may also be used for degenerative disc disease, deformity correction, biopsy, debridement, and tumor management. The anterior approach may also be used for lumbar disc replacement surgery.
The patients undergoing anterior lumbar interbody fusion are operated on under general anesthesia. The patient breathes through an artificial tube and is unconscious during the surgery. The patient is laid on a specially designed operating table with his/her back on the table.
Under complete aseptic conditions, the surgeon gives an oblique incision on the left side of the stomach. The abdominal muscles are split and retracted to the sides. The abdomen’s organs lie inside a protective covering known as the peritoneum, and the surgeon retracts the peritoneum to one side.
The surgeon carefully passes along the sympathetic nerve plexus near the vertebrae to reach the diseased segment. A vascular surgeon usually accompanies the surgeon to securely retract the major blood vessels (aorta) in front of the vertebral column.
The surgeon then uses special forceps to remove the intervertebral disc material and clear the structures impinging on the dural sac from the front. The two vertebrae are then distracted to insert a metal or plastic (PEEK) bone cage filled with bone graft. The bone graft may be taken from the patient’s pelvic bone during the surgery or maybe harvested from a bone bank.
Screws and plates may be utilized to stabilize the construct until the bone graft fuses with the adjoining vertebrae. At times a posterior surgery may also be performed alongside to remove the compressing structures and also stabilize the spine from the back. The incisions are closed in layers, and a bandage may be applied over the skin incision.
The anterior approach offers some advantages as compared with the posterior approach. During the anterior approach, the back muscles are not cut or separated. The cutting of back muscles in the posterior approach has been linked to increased postoperative back pain and decreased strength of the back muscles. The patients treated with the anterior approach experience a faster recovery.
Additionally, the dural sac is not disturbed or maneuvered during the anterior approach. The retraction of the dural sac during the posterior approach has been associated with dural scarring.
The anterior approach also allows the surgeon to place a larger cage and insert the bone graft under compression. The pathologies in the front of the spine are better addressed by the anterior approach than the posterior approach. Patients requiring another surgery who previously had surgery from the back are candidates for the anterior approach.
In the postoperative period, the patients are encouraged to walk on the first day of the surgery. They are usually allowed to continue their daily activities in the following weeks but advised against lifting heavy weights and bending their back. The majority of patients experience relief of their symptoms in the next few weeks.
As with any surgery, there may be complications associated with the anterior lumbar interbody fusion. There may be potential damage to the major blood vessels that may result in massive bleeding. There may be damage to the peritoneum and the abdominal organs.
In some cases, male patients may experience retrograde ejaculation due to damage to the sympathetic nerves. As with other approaches, there may be potential complications of infection, nonunion of fusion, implant breakout, etc.
The risk of complications remains minimal, and the majority of patients experience excellent relief from their symptoms. To get to know the right approach for your spine pathology, discuss it with your fellowship-trained spine surgeon.