Spinal Fusion Complications By Procedure

by Jun 13, 2017

You might think there’s one definitive set of complications associated with spinal fusion that apply to all fusion procedures across the board. In reality, spinal fusion complications vary depending on the type of approach a surgeon uses to access the spine—even the approach varies by surgeon and by case. So it’s important to discuss the details of the surgery with your doctor first, and then make sure you understand the risks based on his or her approach.

Why are there different surgical approaches for fusion? Occasionally it’s determined by the type of pathology present; other times it’s because the patient has had a prior surgery that would make one approach more difficult than another. Mostly, however, it’s a matter of surgeon preference and/or the training they’ve received. Surgeons tend to choose an approach they’re familiar with, in addition to considering what they feel is the safest approach for the case at hand.

Spinal Fusion Complications By Procedure

Currently, fusions are being performed using all four of the following methods:

  • Anterior Lumbar Interbody Fusion (ALIF)
  • Transforaminal Lumbar Interbody Fusion (TLIF)
  • Posterior Lumbar Interbody Fusion (PLIF)
  • Extreme Lateral Interbody Fusion (XLIF)

All of these procedures have one complication in common: a risk of infection. Everyone has bacteria on their skin, and it’s impossible to remove it all, despite the fact that patients are thoroughly prepped before surgery. So there’s always a small chance that bacteria will migrate through a surgical incision and infect the wound.

Beyond infection, let’s take a closer look at the additional complications associated with each type of spinal fusion procedure.


In an ALIF, the surgeon approaches the spine from the front, through the stomach. As part of this procedure, the surgeon must pass through, around, or near several vital organs—the bladder, the kidneys, the ureters (the tubes that connect the kidney to the bladder), and part of the colon—and some major blood vessels, including the abdominal aorta and the iliac. The likelihood of damaging any of these organs is very small, but the risk is real—all of these major structures can be and have been injured during ALIF procedures.

Do you want to know more about back and leg pain relief without fusion surgery? Find out if BalancedBack is right for you.

Damage to a major blood vessel could be life-threatening, while damage to the colon or bladder would require additional surgery or a prolonged hospital stay. There’s also a small risk of a hernia with an ALIF.


The XLIF approach is through the abdominal wall, from the side. This area—called the retroperitoneal space—is the back side of the abdominal cavity. To understand the complications associated with this approach, you need to understand a little bit of anatomy first.

In this area, there’s a large muscle alongside the spine called the psoas. Nerves run down the center of your back and eventually branch off and enter into the psoas before they pass down into the pelvis. In the pelvis, they all coalesce together to form two large nerves—the femoral and the sciatic nerve. 

Complications vary depending on the location of the intended implant—with the most risk occurring at the L4-L5 level of your spine (the two lowest vertebrae). For a surgeon to gain entry to this space, the L4 branch of the nerve—which ultimately becomes part of the femoral nerve—is at risk of being injured. Bruising the L4 nerve will cause temporary weakness in the quadricep muscles in the front of your thigh, making it hard to do things like climb steps. Sometimes, the surgical instruments themselves put pressure on the nerve and may affect blood flow, resulting in a condition called ischemia. Mostly these conditions are temporary, though a small percentage could become permanent. It’s important to note that the chances for nerve damage are reduced at the L3 and L4 levels and even further reduced at levels L2 and L3.

In addition to nerve injuries, there’s a small chance of impacting some of the major structures mentioned in the ALIF—the bladder, ureters, kidney, and blood vessels.  


In a TLIF, the surgeon approaches from the back of your spine, on one side or the other. There’s much less risk of damaging vital structures with this approach. During this procedure, a surgeon gently manipulates the nerve near the spine to gain access, which could result in bruising, stretching, or other damage to the nerve. The chances of nerve injury in this case are small, and in most instances will resolve on its own with time.


Similar to a TLIF, the approach to a PLIF is also from the back, in the middle. The same type of spinal fusion complications associated with a TLIF are also applicable to a PLIF, but the likelihood of stretching and injuring the nerve is greater in a PLIF.

Here’s why: It’s more difficult to work around the nerve from this angle. In a TLIF, the surgeon removes more bone, in effect providing more room to pass by the nerve, remove the disc, and insert the implant. In a PLIF procedure, surgeons simply do not remove as much bone, giving them less space to move. In trying to create extra room, they must work close to the nerve, which leads to a greater risk of nerve injury.  

The BalancedBack Approach

Our BalancedBack surgeons do a TLIF procedure to replace the damaged, painful disc and its facet joints with a total joint implant. It’s different than fusion, which removes the disc and facets and fuses two vertebrae together, resulting in a limited range of movement. Instead of a fusion cage, we insert a prosthesis (like that of a hip replacement) that allows the joint to keep moving. This type of joint replacement procedure helps to replicate your natural range of movement and balance.

Interested in learning more? Click here to learn more about the BalancedBack procedure.

About 3Spine

3Spine is a new kind of healthcare company that vertically integrates the development, clinical research, and delivery of novel healthcare technology.  The BalancedBack Total Joint Replacement is the technology platform developed by 3Spine as an alternative to fusion for the lumbar spine.

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