Laminectomy

Overview of Laminectomy

Posterior spinal decompression is a common surgery that is often performed when non-surgical treatments did not solve the problem. This surgery is mainly done on middle-aged and elderly patients to treat spinal stenosis which is a narrowing of the spaces within your spine that can cause pressure on the nerves that travel through the spine. It’s very common among people above 65 years of age.

The surgery, also called a laminectomy, involves the removal of certain parts of the spine, specifically the spinous process and the lamina, to help alleviate the pressure on the nerves. This part of the surgery is considered crucial to preventing further complications and ensuring speedy recovery. The focus is on relieving pressure in areas such as the central canal (the hollow space in the middle of the spinal column), the lateral recesses (tunnel-like passages for nerves) and the neural foramina (openings between vertebrae where nerves exit the spine).

There are many ways to perform this surgery, including open or minimally invasive laminectomy, hemilaminectomy, laminotomies, and laminoplasty. These procedures can be grouped into two types: direct and indirect. Direct procedures, such as the laminectomy, involve visualizing the protective outer layer of the spinal cord (dural sac) during surgery. In contrast, indirect procedures involve the same process but without visualizing the dural sac. A laminectomy, whether performed alone or combined with spinal fusion, is one of the most common procedures done by a spinal surgeon.

The main goals of the surgery are to reduce neurological claudication (pain caused by too little blood flow during exercise), prevent further symptoms or deficits, and improve your ability to walk and move around.

Anatomy and Physiology of Laminectomy

The basic knowledge of the structure of the back part of the spine, also known as the posterior vertebral arch and laminae, is crucial if we want to understand a surgical procedure known as laminectomy. The laminae, part of this posterior vertebral arch, act as supportive structures that give stability to your spine. They also protect the spinal cord and nerves present in your back.

The laminae are placed in such a way that they stretch from the base of the projecting part of the spine or the spinous process all the way up to the junction of certain structures known as the superior and inferior facet joints. If we talk about the overall structure of the laminae, they have an upper and a lower border; the front area is in contact with a canal in the spine known as the medullary canal while the back portion is connected to the back (or erector spinae) muscles.

The size, shape, and thickness of these laminae are different depending on their location. The laminae’s height tends to reduce from a certain point in the neck (C2) to around the middle of the neck (C4), then it increases until it reaches its highest around the middle of your back or thoracic region (T8). It then begins to gradually decrease while length increases in the lower back, and in the lowest part of the back (L5), it has the shortest height. In terms of width, it steadily decreases from neck to mid-back; it is the narrowest at T4 in the chest area and then slowly increases to be widest at L5 in the lower back.

The thickness of the laminae shows an upward movement from the neck to the lower back regions. A more detailed understanding of the different configurations of the laminae in different areas of the spine could possibly enhance the chances of surgical success and reduce the occurrence of complications like injuries to the nerves or spinal cord.

Why do People Need Laminectomy

Laminectomy is a surgical procedure used mainly when you have a narrow spinal canal, a condition known as spinal stenosis. Several factors can cause this narrowing, such as inheriting a small spinal canal, getting older, or as a result of an accident, tumor, or certain diseases. However, the most common cause is wear and tear changes in the spine due to aging.

Spinal stenosis can occur at different points along the spine, and different classifications help doctors understand the location and devise a surgical plan. Laminectomy is particularly good at treating stenosis in the middle of the spinal canal and the side entrance of the spinal nerves.

The most common type of spinal stenosis occurs in the spine’s center, and the primary symptom is a pain, tingling, or cramping sensation in the lower part of your body. The condition can cause pain that usually increases when you stand or walk and decreases when you lean forward or sit. When spinal stenosis does not improve with non-surgical treatment, a laminectomy is often considered.

Sometimes, when the narrowing is associated with the spine’s instability or other disorders like abnormal curvature of the back, a fusion technique is used along with laminectomy. Fusion helps to stabilize the spine, reducing the risk of future spinal instability. However, in some cases of mild spine displacement due to degeneration, studies have shown varying results regarding the risk of spine instability after laminectomy alone. A recent analysis indicates that there’s no increased risk of instability after laminectomy, particularly in patients without general back pain and those undergoing less invasive procedures.

Laminectomy is also useful when there are primary or secondary tumors, infections like abscesses in the protective layer covering the spine, fractures that compromise the spinal canal, or stenosis alongside a deformed spine.

To diagnose spinal stenosis, doctors use different imaging tests:

* CT scan to measure the size of the spinal canal
* MRI, which is the best imaging method for this condition
* Dynamic flexion/extension films to check for instability and displacement of the spine
* EMG to differentiate nerve disorders of the limbs
* An X-ray of hip and knee to rule out conditions that confuse the diagnosis like arthritis

Different causes of spinal stenosis have been identified as:

1. Congenital (present at birth): Short-limbed dwarfism
2. Acquired (develops over time):

* Degeneration of the spine
* Trauma or accident
* Tumors and cysts, which take up space
* Bony lesions from diseases like Paget and Ankylosing Spondylitis

You might need a laminectomy if:

* The narrowing in your spinal canal isn’t responding to 12 weeks of treatment with medication, physical therapy, and injections
* You have excruciating pain or neurological symptoms that are worsening
* You have a condition known as cauda equina syndrome, which is a rare but serious condition that requires immediate surgery.

When a Person Should Avoid Laminectomy

Spondylolisthesis, scoliosis, and lateral listhesis refer to different kinds of spine conditions. Spondylolisthesis is when one of the bones in your spine slides forward over the bone below it. Scoliosis is a disease that leads to a sideways curvature of the spine. Lateral listhesis happens when there’s a side-to-side (lateral) displacement of the vertebral bones.

Sometimes, a patient might not be the best candidate for spine surgery. This could be due to a few reasons:

-The patient has multiple other health conditions. These other conditions can make surgery more risky or affect the recovery time after surgery.

-The patient is dealing with depression. Mental health plays a crucial role in how well someone can recover and cope with the process of surgery and rehabilitation.

-The patient has difficulty walking. When walking is a challenge, it can hinder recovery after the surgery.

-The patient has scoliosis along with the other spine conditions. The presence of more than one spine condition can complicate the surgical approach and recovery.

Equipment used for Laminectomy

In simple terms, when performing spine surgery, the doctor uses the following equipment:

The table where you lie down during the operation is special because it allows X-rays to pass through it. This type of table is known as a ‘radiolucent table’. It is fitted with frames and foam pads to keep you comfortable and stable throughout the procedure.

They use a device known as a ‘C-arm’, which assists in accurately determining where the incision needs to be made, thus minimizing the size of the cut on your skin.

For the surgical procedure itself, they use a set of instruments referred to as a ‘Laminectomy instrument set’. This includes:

• ‘Bone cutting rongeurs’ and ‘high-speed burrs’, which are tools that help remove bone.
• ‘Kerrison rongeurs’ and ‘forceps’ for grasping and manipulating tissues and other small objects.
• ‘Ball tip’, ‘angled spatula spreader’, and ‘bayonet-shaped curettes’ to help with the procedure, reach different angles and scrape away any remaining tissue off the bone.
• ‘Hollow probes’ to examine the area and deliver medications or fluids.
• ‘Tubular retractors’ and ‘dilators’ for less invasive or ‘MIS’ approaches, which help create a passageway to the area being treated, and to gently move aside and hold back tissues, so your doctor can see and work better.

Who is needed to perform Laminectomy?

For spine surgeries, one or two doctors who specialize in spine surgery, nurses who work in the operating theater, and doctors who put you to sleep (anesthesiologists) will be present. A special kind of monitoring of the nerves, also known as ‘neuromonitoring’, is usually advised during surgeries involving the neck, upper back, or lower back, particularly when there’s a higher chance of your nerves being hurt. These spinal surgeons and their team are there to make sure your surgery goes as smoothly and safely as possible.

Preparing for Laminectomy

A laminectomy, which is a surgical operation done on the spine, is performed while the patient lies face down on a specially-designed support frame with foam pads. The position of these pads, one under the chest and one on the ASIS (a part of your hip bone), allows the abdomen to freely hang. This is done to reduce the pressure in the lower part of the back, hence decreasing the chance of bleeding at the operative site.

To prevent any injury to the nerves located in the armpit, the patient’s arms are positioned out to the sides at a 90-degree angle and slightly bent. This posture, again, is designed to avoid any additional pressure or injury during the procedure.

How is Laminectomy performed

A laminectomy is a type of back surgery that can be performed under two different methods: a traditional open approach or a minimally invasive technique.

The traditional method involves making a cut in the middle of the back. The length of the cut varies depending on the specific procedure, but for a single level, it’s normally between 1.2 to 1.6 inches long. After the incision, the surgeon will then carefully expose and remove parts of the vertebra (spine), like the spinous processes and dorsal laminae. These steps help expose the ligamentum flavum, a yellowish tissue that connects adjacent vertebrae, which is then removed or altered to relieve pressure on the spinal nerves. In some cases, the surgeon will also need to conduct a facetectomy, which is a procedure to relieve pressure on a nerve root by removing a part of the facet joint – a joint that aligns our spinal cord. During all of this, the surgeon will take great care to avoid damage to specific parts of the spine in order to reduce the risk of instability after the operation.

On the other hand, minimally invasive surgical (MIS) techniques include procedures called laminotomy and microendoscopic laminotomy. These methods use smaller cuts and tubular retractors, which are basically tubes inserted through your incision to hold the muscles and skin away from the operating area. This allows the surgeon to operate without making large incisions. Studies have suggested that these procedures may result in less damage to the muscles in your back, less blood loss during the operation, and less pain after the operation.

While MIS techniques may improve some experiences (like recovery time and pain) compared to open procedures, more research is needed to fully understand their cost-effectiveness.

A study comparing the traditional method of laminectomy to three techniques that don’t involve removing the spinous process was conducted. It suggested that some of these techniques might cause less back pain after the operation. However, there was no clear difference in hospital stay, operation time, and complications compared to conventional laminectomy.

In essence, the surgeon will first position the patient correctly on the operating table, then make the necessary incision(s). The spine is then we will carefully located and the necessary bone and tissue removal is performed to decompress the area. The wound is then closed layer by layer after making sure there’s no bleeding and, sometimes, inserting a drain. The particular approach to be used for each patient would depend on various factors such as their overall health and the specific cause for the surgery.

Possible Complications of Laminectomy

If you’re having spine surgery, there are a few risks and complications that might occur. One is an injury to the pars interarticularis, a specific part of each spinal bone. If more than half of this area is damaged on both sides or fully damaged on one side during operation, another surgery called fusion surgery may be needed. This is especially important when operating on the upper part of the lower back (L1-3) as it has a small working area for surgery.

Another potential complication is bony re-growth. In some cases, a condition called kyphosis can take place. This is where the backbone develops an abnormal forward-curving, due to the structure keeping the spine straight being disrupted.

There’s also the possibility of a spinal epidural hematoma, which is a blood clot occurring near the spine, posing a higher risk specifically around the third lumbar vertebrae (L2/3).

A complication called a dural tear could occur as well. The dura is the outermost layer that surrounds the spinal cord, and it can be inadvertently torn during surgery. This complication happens in about 3.1% to 13% of first-time surgeries, and in 8.1% to 17.4% of repeat surgeries. A tear can potentially increase the chance of infection at the surgery site, cognitive disturbances post-surgery (delirium), and other issues. This is more common in elderly patients and those who have had previous surgeries. However, the method of closure for the tear doesn’t affect the need for additional surgery or the likelihood of complications. The usual treatment is to repair the leak and then have bed rest.

Lastly, operating with minimal access can reduce the risk of a condition called pseudomeningocele and CSF (cerebrospinal fluid) fistula. These complications arise due to the formation of unnecessary void spaces during or after the surgery.

Though extremely rare, a mortality rate of 0.5 to 2.3% accompanies these procedures, emphasizing that, as with any surgery, there are risks involved.

What Else Should I Know About Laminectomy?

Laminectomy is a common surgical procedure to treat spinal stenosis, which narrows your spinal canal. This surgery can provide relief from pain and speed up recovery, with a low chance of complications. It’s also helpful in treating other conditions affecting the spinal canal, like tumors or an abscess, though it hasn’t been definitively proven to be better than non-surgical treatments for spinal stenosis.

Laminectomy has a 90% success rate, with over 75% of patients reporting satisfaction. It’s particularly effective at resolving pain and weakness quickly. However, some sensations, such as abnormal prickling feelings (dysesthesias), can take up to two years to go away. About 18% of patients need another surgery within five years.

Reasons the surgery might not work can include adjacent segment stenosis (narrowing of the spinal canal next to the operated area), disc herniation (when the filling of a disc in your spine pushes out), spondylolisthesis (a slippage of your vertebra), or the return of stenosis.

There are also variations of laminectomy depending on the patient’s specific condition. Sometimes, along with the laminectomy, surgeons perform decompression, which relieves pressure on the spinal cord. They may also carry out a fusion, which joins two or more vertebrae together. Though this can carry a higher risk of blood loss, infection, long hospital stays, and higher costs, it’s beneficial for patients with spondylolisthesis, scoliosis, and lateral listhesis (sideways curvature of the spine).

Other types of treatments include endoscopic decompression, which is less invasive and preserves stability, and minimally invasive tubular decompression, which requires less recovery time and results in lesser blood loss during surgery.

Surgeons also use various tools and methods to improve the success of the procedure, such as machine learning, and artificial intelligence to improve decision making, surgical simulations for practice, and intraoperative sonography to confirm if the space around the spinal cord has been restored.

In rare cases, a 3D-printed artificial lamina, a part of your vertebra, may be used to help stabilize your spine. All of these techniques aim to ensure that the laminectomy or other treatments are successful in relieving your spinal stenosis.