Updated: Nov 26, 2020
Minimally invasive spine surgery (MISS)
Written by Bansal Gaurav MBBS, MS, MCh (AIIMS), IFAANS (USA)
If you recently learned you need lumbar fusion spine surgery, you might expect to spend a few days in the hospital, a slow recovery, and a long scar to remind you later of the procedure. But, fortunately, none of those things are a given anymore thanks to minimally invasive spine surgery (MISS). Many patients now can have their procedure performed in an outpatient facility and go home the same day.
While many types of MISS can be performed in an outpatient surgery center, this article will focus on minimally invasive lumbar (low back) fusion.
New Surgery, New Setting: Minimally Invasive Spinal Fusion
Unlike a traditional surgical spinal fusion—sometimes called an open spinal fusion—the goal of a minimally invasive lumbar fusion is to minimize the size of the incision and the exposure of the spine, which lessens the amount of healing you have to do. MISS uses specialized instrumentation that allows the surgeon to avoid disrupting soft tissues (eg, muscles) in the spine, resulting in less pain. These procedures are typically safer, quicker, and promote a faster recovery than traditional spine surgery.
The potential benefits of minimally invasive spine surgery include:
Less blood loss
Lower risk of muscle and soft tissue damage
Lower risk of infection
Reduced postoperative pain
Reduced pain medication use
While MISS often focuses on the size of the incision, it’s really a larger concept of being minimally traumatic to the body and the muscles in the low back. The MISS technological advances have not only given spine surgeons a new way to perform lumbar fusion, but they’ve also enabled the surgery to be performed in an outpatient setting. You can now have your surgery performed in a comfortable atmosphere, and many patients return home same day—as opposed to the two to three-day hospital stay for a traditional fusion.
Conditions Treated with Minimally Invasive Lumbar Fusion
Many of the most common spinal disorders may be treated using minimally invasive lumbar fusion, including:
What Happens During a Minimally Invasive Lumbar Fusion Surgery?
Simply put, a fusion procedure fuses (ie, joins) together two or more bones in your spine (eg, vertebral bodies). Bone graft is used to help stimulate fusion. Bone graft may be packed into the empty disc space (after micro-discectomy; surgical removal of an intervertebral disc), interbody device and/or instrumentation implanted to immediately stabilize one or more levels of the spine. Over time, the bones grow and heal together into a solid block, which further stabilizes the spine.
Two common outpatient MISS fusion procedures are (1) transforaminal lumbar interbody fusion (TLIF) and (2) posterior lumbar interbody fusion (PLIF).
In a TLIF, you are positioned face-down on the operating table and the surgeon works from the side of the spine.
In a PLIF, the surgeon accesses your spine from the middle of the back.
The overview below describes both a TLIF and PLIF
Prior to surgery, you are positioned on the operating table face-down, and general anaesthesia is administered.
One of the key instruments used during MISS lumbar fusions is a tubular retractor. This device separates muscles and holds the muscles apart throughout the operative procedure. In many traditional non-MISS procedures, spinal muscles may need to cut to allow access to the surgical site.
The surgeon uses a surgical microscope or operative loupes—eyeglasses with microscopic vision capabilities—to help visualize and magnify the area through the tubular retractor.
Compared to traditional open fusion, which typically requires a 5- to 6-inch incision, the incision for a minimally invasive fusion is only about 2-inches long—the same length as the incision for a lumbar laminectomy. The smaller incision means less tissue disruption and less postoperative pain for the patient.
After the tiny incision (similar to a skin puncture) is made, the tubular retractor is inserted through the skin and down toward the spinal column. Unlike traditional open fusion where the surgical area often exposes more than the spinal level to be fused, the MISS technique isolates the surgical area to only the posterior aspect (the lamina) of the vertebral body.
The surgeon enters the disc space between the adjacent vertebral bodies using small instruments that fit through the center of the tubular retractor. The intervertebral disc is removed (ie, micro-discectomy) and the disc space is prepared for implantation of an interbody device. An interbody device fills the empty space and restores disc space height, which is important to create sufficient room for the nerve roots. But before the interbody device is implanted, the surgeon packs it with bone graft. After the interbody device is in place, more bone graft is packed around the device.
Using special bone screws known as cortical screws, the interbody device is secured in place. The cortical screws are implanted into the upper and lower vertebral bodies and forms a bridging scaffold that fixes the two vertebral bodies together.
At the end of the procedure, the surgeon removes the tubular retractor, which allows the muscles to naturally move back into their original positions. For fusions involving one level, surgery typically takes one to two hours at an advanced center; a surgery impacting two levels may take up to three hours.
Minimally Invasive Lumbar Fusion Considerations
Minimally invasive lumbar fusion has a host of benefits over traditional fusion—less blood loss, smaller incision, and quicker recovery time to name a few. But, not everyone is a candidate for a minimally invasive spinal fusion, particularly in an outpatient setting.
Surgical treatment of some low back (lumbar spine) conditions require a traditional open approach. Therefore, your particular diagnosis and other factors (eg, overall health) are important considerations in making the decision whether MISS is right for you. It is important to understand that if you have a serious health problem, such as cardiovascular disease, your surgeon may recommend you undergo the MISS procedure in the hospital, where other specialists (eg, cardiologists) are readily available.
As any spine fusion surgery, there is a risk of non-union—that is, when bones don’t fuse as planned. Your surgeon will review all potential complications as a result of undergoing minimally invasive lumbar fusion with you prior to surgery.
Advances in technology and instrumentation have paved the way for the ever-growing effectiveness of minimally invasive lumbar spinal fusion. Minimally invasive procedures require smaller incisions with faster recovery, and patients who undergo MISS in an outpatient setting enjoy the additional benefits of being in a comfortable environment and going home the same day.