Anterior lumbar fusion--also called anterior lumbar interbody fusion, or ALIF--may relieve pain caused by instability in the spine. To stabilize damaged vertebrae, the surgeon inserts a bone graft to stimulate the healing process that eventually welds the affected bones together. The lumbar or lower spine can be accessed through an incision in the back--the posterior approach--or through the abdomen--the anterior approach. Operating through the abdomen avoids damage to the nerves and muscles of the back, but may cause other complications.
Damage to Blood Vessels
The anterior approach to lumbar fusion may cause damage to the nearby large blood vessels of the legs, according to the Spine-Health website. Excessive blood loss has been reported to be as high as 1 to 15 percent of patients undergoing anterior lumbar fusion. The posterior approach avoids the blood vessels, but may cause nerve or muscle damage.
Retrograde Ejaculation
Male patients who undergo anterior lumbar fusion involving the L5-S1 space--the space between the lowest lumbar vertebra and the first sacral vertebra--may experience damage to the nerves that control the valve that propels ejaculate out of the body. Although the sensation of ejaculation may be the same, the patient's ability to father a child is affected because the ejaculate goes into the bladder. Fewer than 1 percent of male patients experience this complication, and those who are affected tend to recover normal function within a few months to a year.
Nonunion
Approximately 5 to 10 percent of anterior spinal fusion patients do not achieve a full healing of the bones, called nonunion, according to Spine-Health. If the patient's pain is relieved, a second operation is not necessary. However, some patients may require a repeat procedure to achieve stability and pain relief, according to the American Academy of Orthopaedic Surgeons.
General Risks of Spinal Fusion
Between 1 and 3 percent of all spinal fusion patients experience an infection or excessive bleeding, says Spine-Health. Failed back surgery syndrome, in which union occurs but the patient's pain level does not improve, is also a possible complication with both the anterior and posterior approaches. Although rare, blood clots can form in the legs during or after surgery and, if one breaks off and travels to the lungs, the results can be life-threatening, according to the American Academy of Orthopaedic Surgeons.
