A laminotomy is a minimally invasive procedure designed to alleviate the symptoms of spinal cord impingement or nerve root compression by removing a portion of the bony vertebral arch known as the lamina. A laminotomy is not to be confused with a laminectomy, which generally is an open back or neck operation and entails the removal of the entire lamina.
The goal of a laminotomy procedure is to create more space in the spinal canal, thereby relieving pressure on nerve tissue that may be causing pain, muscle weakness, or other neuropathic symptoms in the back, neck, or extremities. In utilizing a laminotomy, rather than a laminectomy, a surgeon seeks to preserve as much vertebral bone as possible while relieving spinal nerve compression.
A laminotomy may also be utilized to provide a surgeon access to the ligamentum flavum, a spinal ligament that can thicken or buckle over time, reducing the amount of space in the spinal canal available for the spinal cord. Removal of this ligament, combined with the removal of a portion of the lamina, can help reduce the problematic spinal cord compression.
The portion of the lamina targeted for removal depends on the location of the anatomical abnormality responsible for the symptomatic nerve compression. If, for example, a spinal osteophyte (bone spur) develops along the top edge of the lamina, it is said to be in a “superior” position. If it were on the bottom edge of the lamina, it would be considered “inferior.” In addition, the source of nerve compression may be located on the lamina to the right or the left of the bony protrusion known as the spinous process, which is the knobby bone you can feel at each vertebral level if you run your hand along your spine.
In many cases, the lamina itself may not be responsible for nerve compression, but the removal of a small portion of a lamina can open up space in a spinal canal that’s being encroached upon by a degenerative spine condition. For instance, a herniated disc or an enlarged facet joint can restrict space in the the spinal canal, but this narrowing can be alleviated by excising bone from the lamina.
The contrast between an endoscopic laminotomy and an open spine laminectomy is not limited to the amount of bone material removed from the spine. The major difference between the procedures is the minimally invasive nature of an endoscopic laminotomy versus the relatively high invasiveness of a laminectomy. When a laminotomy is performed endoscopically, it means the surgeon gains access to the area of neural compression through a small tube, rather than a large, open incision. The contrast between the two surgeries is best illustrated by comparing the requirements of an open spine laminectomy with the steps of an endoscopic laminotomy.
A laminectomy generally necessitates:
The use of general anesthesia
One or more days of hospitalization
A large incision, typically four inches or more
Cutting of muscle and other soft tissue for access to the spine
The complete removal of the posterior portion of the vertebral arch, including the lamina and the spinous process, along with the adjacent muscle and ligamentous tissue
The insertion of metal hardware to stabilize and permanently immobilize the vertebral segment, along with bone graft material in some cases
In contrast, an endoscopic laminotomy entails:
The use of local anesthetic and deep IV sedation
No hospitalization
A small incision, usually no more than one inch
The displacement, rather than the cutting, of muscle and other soft tissue
Removal of only as much bone and other material necessary to relieve spinal cord or spinal nerve compression
No metal hardware or bone graft material implantation
A laminotomy involves the insertion of a series of dilating tubes, each larger than the next, to provide access to the affected vertebral segment. Once the final tube (called a tubular retractor) is in position, the dilating tubes are removed. Surgical instruments are then manipulated through the tubular retractor. This might include a camera, a light, and other tools used to clear away the bone and/or other tissue that is responsible for spinal cord or nerve root compression. Excess bone and other material are extracted through the tube. Once decompression has been achieved, the tube is removed slowly, allowing muscles to return to their previous position. One or two stitches may be necessary to suture the incision closed.
A Laminotomy of the Spine is used to treat the following conditions:
Spinal Stenosis
Herniated disc
Bulging disc
Pinched nerve (nerve root compression)
Bone spurs
Arthritis of the spine
Ligament hypertrophy or ossification
A laminotomy procedure is most often used to alleviate symptoms associated with spinal stenosis, which is the narrowing of the spinal canal. Spinal stenosis often leads to compression of the spinal cord, the elongated bundle of nerve fibers that runs from the base of the skull downward to the lower back and serves as a conduit of sensory and motor signals between the brain and the rest of the body.
Stenosis, or narrowing, is possible at any level of the spine, but is diagnosed most frequently in the lower back, or the lumbar region. The components of the spinal anatomy within the lower back – vertebrae, intervertebral discs, facet joints, and ligaments – are particularly susceptible to the degenerative effects of aging and repetitive movement. This is because the lower back bears most of the weight of the upper body, and therefore must work harder to support the wide range of motion that takes place as we bend, twist, sit, walk, and perform almost any physical activity.
The term spinal stenosis is a general way to describe the narrowing effect of several commonly diagnosed spine conditions that are known to lead to a constriction of the spinal canal. These conditions include:
Bulging disc – Occurs when the outer wall of an intervertebral disc (called the annulus fibrosus) begins to extend beyond its normal boundary and into the spinal canal. This is often a result of diminished water content within the soft central portion (nucleus pulposus) of the disc, which reduces the disc’s flexibility and height.
Herniated disc – Occurs when the annulus fibrosus ruptures and a portion of the nucleus pulposus extrudes into the spinal canal. This often begins as a bulging disc, which develops into a herniation when the outer wall no longer can contain the buildup of excess pressure inside the disc.
Pinched nerve – The spinal cord is housed within the spinal canal, a long, vertical passageway created by the round openings in the center of each of the stacked vertebrae. The vertebrae also provide small passageways (called “foramina”) for nerve roots to branch off the spinal cord and exit the spinal column on either side, where they form a network of nerves that serves the entire body. If the spinal canal or foramina are narrowed in any way, the spinal cord or one of its nerve roots can become “pinched” or compressed. This condition is often referred to as a pinched nerve.
Bone spurs – Occurs as the body’s response to diminished joint stability, as is experienced with spinal osteoarthritis. These spurs, or osteophytes, are smooth protrusions of excess bone that grow along the edges of a facet joint or another part of a vertebra, possibly producing either spinal cord compression or nerve root compression.
Osteoarthritis of the spine – The facet joints are the hinge-like connections in between vertebrae that allow the spine to bend and twist. The combined effects of time and use can cause the facet joints to lose their smooth, rubbery coating of cartilage. This loss of joint cartilage over the years is called osteoarthritis, a condition that can lead to the inflammation and enlargement (hypertrophy) of the facet joints. Swollen facet joints may block the passageways where the spinal cord and nerve roots are located, compressing those nerves and causing pain and other symptoms.
Ligament hypertrophy or ossification – With age, the ligamentum flavum either begins to thicken or bunches together as it loses its ability to “snap back” into place after spinal movement. When the ligament thickens or bunches, the spinal cord may be compressed (causing lower back pain) while the patient is standing upright or walking. Some patients may feel relief when bending forward, as when leaning on a shopping cart.
An important thing to remember about the conditions that are treated by a laminotomy is that they often occur simultaneously. In other words, if a patient is diagnosed with a bulging disc, he or she may also have bone spurs along the edges of the lamina or another common site for spinal osteophytes, the foramina (the openings where nerve roots exit the spinal canal). In these cases, a laminotomy may be performed in conjunction with another type of endoscopic procedure, called a foraminotomy, which opens up clogged foraminal openings. This combination of procedures can be used to provide relief from one of the most common sources of spinal nerve compression, a condition known as lateral recess stenosis.
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