What You Need to Know
To fully understand how Minimally Invasive Spine Surgery (MISS) works, it is useful to know about the anatomical structure of your back.
The spine, commonly known as the vertebral column is the set of bones that runs down from your sacrum (the bone in your lower back that is located between your hips) to the base of your skull. The anatomy of your spine is divided into four sections: 1) cervical spine (neck), 2) thoracic spine (upper back), 3) lumbar spine (lower back), and 4) the sacral region. It is made up of vertebrae, discs, muscles, and spinal nerves. Individually, they are described as:
- Vertebrae – the ridge-shaped bones that make up your spine’s structure; aside from forming the shape of your back, it protects all your nerves running down your brain to the different parts of the body
- Discs – also termed as intervertebral discs, they are the cushions in between each of your vertebra cushioning your joints and providing support; they are full of gel that makes them tough and flexible. The gel inside the discs are what comes out in herniated discs (derived from Latin word ‘hernia’ which means tear/rupture/protrude)
- Back muscles – a group of tissue supporting the spine; they also work together to hold the body upright and facilitate movement
- Spinal nerves – they are fibers (like a wire cable) that send and receive signals between the body and the brain
If your back hurts, never think that you are alone. In fact, more than 30 million Americans complain of back pain at any given time. Statistics even report that the single leading cause of disability worldwide is low back pain (according to researchers from University of Warwick). Back pain can range from mild conditions such as simple muscle spasms to muscle strains.
However, there are more severe problems than muscle spams or sprains. These serious back related conditions include Degenerative Scoliosis, Spinal Trauma, Spinal Malignancies, Spondylolisthesis, Spinal Stenosis, Sciatica, and Herniated Disc that can cause individuals to experience disabling chronic back pain. These spinal problems often require surgery.
Minimally Invasive Spine Surgery
Fortunately, medical advances in the modern era gave way to a new option to treat or relieve chronic back pains and spinal problems. While traditional surgery (a.k.a. open approach) requires larger openings and longer incisions, Minimally Invasive Spine Surgery can be performed through small openings/incisions at the back allowing for less complications and a quicker recovery time.
How Does It Work?
As we have discussed, the back is made up of vertebrae, discs, spinal nerves, and muscles covering these three. This anatomical arrangement keeps the vertebrae, discs, and spinal nerves located deep inside the body. Any approach to these parts requires moving the muscles out of the way.
Instead of creating a long incision at the back and moving the muscles away from the spine, Minimally Invasive Spine Surgery is facilitated by creating a small incision. To see the spinal area without moving the entire muscles covering the vertebrae, guiding instruments and tiny video cameras are inserted through these small incisions (openings).
Various methods can be used to facilitate this approach. Some of them include:
- Use of a Tubular Retractor – This technique involves progressive retraction of the soft tissues, in contrast to cutting directly through the muscles. By using these tubular retractors to keep the muscles out of the way, your surgeon can access the problematic spine without having to expose your entire back.
Sometimes, your surgeon will also use a microscopic endoscope to assist with carrying out the surgery with a minimal access strategy.
Once the procedure is finished, the retractor can be removed, allowing the retracted tissues to come back together. The incisions can often be small depending on the type of surgery and the severity of the condition.
- Percutaneous Placement of Rods and Screws – This method is only done if it is necessary to place rods and screws to immobilize or stabilize the spine or to facilitate fusion of spinal bones. Traditional approaches for placement of these kinds of instruments requires removal of a large part of back muscles. With minimally invasive spine surgery, rods and screws are inserted without dissecting or cutting the underlying tissue.
With the use of X-ray images, guide instruments/wires are inserted through the skin, then through the vertebral column and through the desired paths for the rods or screws to be placed.
These guide instruments/wires are subsequently removed after facilitating the passage of rods to connect separated bones and secure the screws.
- Direct Lateral Access Routes – This technique is usually performed for cases involving the lumbar spine. It is termed lateral access because the spine is approached from the patient’s side (laterally). This approach is common because fewer muscle tissues are blocking the way of the spine. The most common approach for lateral access is XLIF.
XLIF: eXtreme Lateral Interbody Fusion
XLIF is a minimally invasive procedure used to treat a variety of lumbar spinal disorders accompanied by long-term back or leg pain that has not responded to other non-surgical treatments including steroid injections, physical therapy and pain medication.
During the XLIF procedure, the lumbar spine is approached from the patient’s side and the surgeon will use an X-ray to precisely position and locate the operative space and the disc that will be removed. Next, your skin will be marked at the site where the two small incisions will be made. Your surgeon will use the latest instrumentation to access the spine in a minimally disruptive manner. The surgery is performed through a muscle that lies next to the lumbar spine known as the psoas muscle. Next, the surgeon will prepare the herniated disc by removing the disc tissue which will allow the bones to be fused together. Several X-rays will be taken to ensure the preparation and location is correct.
Once the disc has been prepared, the surgeon will then place a stabilizing implant (an artificial graft) into the space to restore the disc height and enable the bones to fuse together. Once in position, a final X-ray will be taken to confirm correct implant placement. Depending on the patient’s condition and in the event that further stabilization is necessary, the surgeon may choose to insert additional screws, rods, or plates into the vertebrae.
The XLIF procedure is made safe with the use of a technologically advanced monitoring system that allows surgeons to monitor nerve health, function, and location during surgery
- Thoracoscopic Access Routes – In certain conditions, spine surgery may be done by accessing the anterior portion of the torso. A traditional method often involves large incisions through the chest which often require removal of few ribs. Minimally Invasive Spine Surgery using Thoracoscopic Access Routes method relies on the use of tiny cameras inserted into the multiple small openings/incisions to facilitate surgery.
- “Minimally Invasive Spine Surgery.” Mayfield Brain & Spine, Neurosurgery, Spine surgeons, Brain surgeons, Cincinnati, Ohio. Mayfield Clinic, Web. <http://www.mayfieldclinic.com/PDF/PE-MinimallyInvasiveSpine.pdf>.
- “Minimally Invasive Spine Surgery – How Does It Work?.” American Association of Neurological Surgeons. Web. <http://www.aans.org/Patients/Neurosurgical-Conditions-and-Treatments/Minimally-Invasive-Spine-Surgery>.
- “Spine Anatomy, Anatomy of the Human Spine.” Mayfield Brain & Spine, Neurosurgery, Spine surgeons, Brain surgeons, Cincinnati, Ohio. Mayfield Brain & Spine, Web. <http://www.mayfieldclinic.com/PE-AnatSpine.htm>.
- The University of Warwick. “Global burden of low back pain.” ScienceDaily. ScienceDaily, 21 March 2018. <www.sciencedaily.com/releases/2018/03/180321130901.htm>.