Lumbar decompressive surgery
Introduction
Lumbar decompressive surgery is an operation to relieve pressure on the spinal nerves in the lower back. It is often used to treat a condition called spinal stenosis.
Spinal stenosis is the narrowing of areas of the spine. It occurs when the bones, ligaments or discs of the spine squash the nerves of the spine causing pain, usually in the lower back and legs.
Causes of spinal stenosis include:
- age-related degeneration of the spine,
- changes in the ligaments of the spine, and
- diseases of the bone, such as Paget’s disease.
Other conditions that may require lumbar decompressive surgery include:
- a slipped (herniated) disc,
- spinal tumours, and
- spinal injury.
Lumbar decompressive surgery is recommended when the pain in your back and legs is affecting your quality of life and alternative treatments, such as pain relief and physiotherapy, have not worked.
Types of surgery
There are two types of lumbar decompressive surgery:
- A laminectomy or partial laminectomy removes or trims the bony arch of a vertebra (bone) or ligaments of the spine to relieve the pressure on the spinal cord.
- A discectomy removes the damaged or bulging part of a slipped disc to relieve pressure on the spinal cord.
Outlook
70% and 75% of patients experience a significant improvement in leg pain after lumbar decompressive surgery. 20-25% of patients experience an improvement, but still have some pain.
The success rate for microdiscectomy (keyhole surgery) is slightly better, with 80-85% of patients experiencing an improvement in their leg pain.
How the spine works
- Your spine extends from your skull to your pelvis. It is made up of 24 individual bones called vertebrae, which are stacked on top of each other.
- The front of each vertebra is solid and is called the vertebral body. Behind the body of each vertebra is an arch of bone called the lamina. The arches form a hollow channel known as the spinal canal or vertebral canal, which protects the spinal cord and nerves.
- A pair of spinal nerves branch out (one to the left and one to the right) from each vertebra. These nerves are called nerve roots and pass through gaps in the arches where they join up to provide sensation and movement to parts of the body. The gaps are called foramens.
- The vertebrae are separated by soft pads or discs that act as shock absorbers.
- Each vertebra also has two sets of joints called facet joints which, with the discs, allow the spine to bend.
- The nerve root foramens are covered by the discs at the front and the facet joints at the back.
- The vertebrae are also held together by tough bands called ligaments. Together with the spinal muscles, these give the back its strength.
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When should it be done?
When lumbar decompressive surgery is needed
Conditions that may require lumbar decompressive surgery include:
Spinal stenosis
Spinal stenosis is the narrowing of the central spinal canal or side root canals of the spine. This narrowing causes pressure on the nerves in the canal, leading to pain, usually in the lower back and legs.
Causes of spinal stenosis include:
- Age-related degeneration of the spine. The main cause of spinal stenosis is natural age-related degeneration. This is often linked to osteoarthritis. As the vertebrae (bones) of the spine begin to weaken and deteriorate, they rub against each other. This causes bony growths called bone spurs, which can cause the spinal canal to narrow.
- Changes in the ligaments of the spine. Like the bones of your spine, the ligaments in your back degenerate over time and can become stiff and thick. This loss of elasticity can have the effect of narrowing your spinal canal.
- Diseases of the bone. Diseases that affect bone growth, such as Paget’s disease and achondroplasia, can cause malformation of the bones of the spine and a narrowing of the spinal canal.
Slipped (herniated) disc
A slipped or herniated disc is when the tough coating of a disc in your spine tears, causing the jelly-like filling to seep out. The torn disc can press on the surrounding nerves causing pain in your back and legs.
A slipped disc can happen at any age, but is more common in people between 20 and 40 years of age. It is usually caused by a combination of minor degeneration in the disc combined with trauma. The trauma can be minor, such as a cough or sneeze.
A slipped disc can press on the nerve sac in the spinal canal causing back pain, or on the surrounding nerves causing pain in the back and legs.
Spinal tumours
Abnormal growths and tumours can form along your spine. These are usually benign (not cancerous), but growing tumours may compress your spinal cord and nerve roots causing pain.
Injury
Injury to your spine, such as dislocation and fractures, or the swelling of tissue after spinal surgery, can put pressure on your spinal cord or nerves.
When to consider surgery
Lumbar decompressive surgery is considered as a treatment for spinal stenosis when:
- pain relief medication and other treatments have failed to help your symptoms,
- the pain is so severe it is interfering with your quality of life, including work and sleep,
- you have had an MRI scan that shows you have a disc, bony spur or thickened ligament pressing on a nerve, or
- you have cauda equina syndrome, a rare and severe form of spinal stenosis. Pressure on the nerves in the lower back causes numbness in the buttocks and prevents you from urinating. In this case, emergency surgery is needed.
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How is it performed?
Before the operation
If you and your consultant decide that you could benefit from lumbar decompression surgery, you will be put on a waiting list. Your doctor or surgeon should be able to tell you how long you are likely to have to wait in your area.
To help you recover from your operation and reduce your risk of complications, it helps if you are as fit as possible beforehand. As soon as you know you are going to have lumbar decompressive surgery, try to:
- stop smoking,
- eat a healthy diet,
- do regular exercise, and
- lose weight if you are overweight.
You will be given a pre-assessment appointment a few days before your operation. Your surgeon will do an X-ray and MRI (magnetic resonance imaging) scan of your spine. The appointment may also involve having some blood tests and a general health check to make sure that you are fit for surgery.
You can also use your pre-assessment appointment as an opportunity to discuss any concerns or ask any questions about your operation.
The operation
You will be admitted to hospital on the day of your operation or the day before. Your surgeon and anaesthetist will explain what will happen during your operation. This will give you the opportunity to ask any questions you may have.
Before going for your operation, you will be asked to sign a consent form for the operation and the anaesthetic. This confirms that you know what the operation involves and the risks.
You will not be allowed to eat or drink for six to eight hours before your operation.
During lumbar decompressive surgery, you will usually be lying face down on a special curved mattress. This reduces the pressure on your chest, abdomen and pelvis. Your spine will be flexed to help expose the compressed nerve. Surgery usually takes between one and two hours.
The goal of lumbar decompressive surgery is to relieve pressure on your spinal cord or nerves and to maintain the strength and flexibility of your spine.
Laminectomy or partial laminectomy
A laminectomy is done to remove areas of bone or ligament that are putting pressure on your spinal cord.
- The surgeon makes a straight incision over the affected section of the spine and down to the lamina, the bony arch of your vertebra.
- The ligament joining the lamina is removed to view the affected nerve root.
- The surgeon will then pull the nerve root back towards the centre of your spinal column and remove part of the bone or ligament causing you pain. This will relieve the pressure on your spinal nerves.
- The incision is then closed and stitched.
Discectomy
A discectomy is done to release the pressure on your spinal nerves caused by a bulging or slipped disc.
- The surgeon makes an incision over the affected area of your spine down to the lamina, the bony arch of your vertebra.
- The ligament joining the lamina is removed to view the affected nerve root.
- The surgeon will then pull the nerve root back towards the centre of your spinal column and will remove just enough of the disc to stop pressure on the nerves. Part of the disc needs to stay to keep working as a shock absorber.
- The incision is then closed and stitched.
Keyhole Surgery
Discectomies and laminectomies are usually performed through a large incision in the back, known as open surgery. In some cases, they may be performed using a microscope (microdiscectomy) or a keyhole technique known as microendoscopic surgery. In this case, the operation is done using a tiny camera and surgical instruments that are inserted through a small incision in your back. The surgeon is guided by viewing the operation on a video monitor.
Microendoscopic back surgery is complicated and is not suitable for all patients (this depends on the exact problem causing your back and leg pain). There is a slightly higher risk of injury than with an open operation. However, this technique may allow your procedure to be carried out as a day case, with a quicker recovery time.
Who will perform your operation?
Your operation will be performed by a neurosurgeon or an orthopaedic surgeon who is experienced in spinal surgery. They may be helped by junior doctors.
You should be told at your pre-operative assessment which surgeon will be doing your operation and may be introduced to them. Ask if you are not told who will be doing your operation.
How can I prepare for going into hospital?
- Get informed. Find out as much as you can about what your operation involves. Your hospital may provide written information or video.
- Arrange help. Organise a friend or relative to help you at home after you return from hospital.
- Sort out transport. Arrange for someone to take you to and from the hospital.
- Prepare your home. Before you go for your operation, put your TV remote control, radio, telephone and medications close to where you will spend most of your time when you come out of hospital.
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Risks
Like all surgical procedures, lumber decompressive surgery carries some risk of complications. Repeat operations have a higher risk of complications than first-time operations.
Complications may include:
Risks from general anaesthetic
There are a number of serious complications associated with general anaesthetic, but these are very rare. Rare complications could include a heart attack, blood clot in the lung or an allergic reaction, any of which could be fatal.
Paralysis
The risk of paralysis after surgery is low. It could occur if there is bleeding into the spinal canal after surgery or the blood supply of spinal nerves is damaged.
Infection
There is always a risk of infection following an operation. Superficial infections of your wound after surgery are not usually serious and can be treated with antibiotics. You are at a higher risk of infection if you are diabetic, on steroids or have a lowered resistance to infection.
Deep spinal infections are much more serious but less common, occurring in less than 1% of cases. If a deep infection occurs, it can require repeat operations and a long course of antibiotics.
Leak of spinal fluid (incidental durotomy)
This is when a hole is made in the lining of the spinal canal allowing the spinal fluid to leak out. The surgeon may intend to do this as part of the operation. Or it may occur as a result of the disc or bone being stuck to the lining of the spinal canal.
The hole in the spinal lining can usually be repaired with stitches or a patch but sometimes it is safer to leave it to heal. The leak of fluid usually dries up within a few days and there is no long-term effect.
Damage to spinal nerves or blood vessels
Having spinal surgery may cause damage to spinal nerves and increased numbness or pain after your operation. In some cases, it may cause paralysis of the legs or permanent bowel problems.
Damage to blood vessels can result in life-threatening bleeding if the main blood vessels are affected. This is extremely rare.
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Recovery
Waking up
When you wake up after your surgery, your back may feel sore and you will probably be attached to one or more tubes, including:
- an intravenous drip to make sure you do not get dehydrated,
- a drain to take away any fluid from your wound,
- a catheter if you are having difficulty urinating, and
- a pump to deliver painkillers directly into your veins every few hours.
The tubes are only usually attached for a short while after your operation.
Discomfort
Immediately after surgery, you will have some pain in and around the area of your operation. You will be given pain relief to make sure you are comfortable and to help you move. The original pain in the leg usually improves immediately, but if it does not, tell the nurses and your doctor.
A very small number of people experience difficulty passing urine after the operation. This is usually temporary, but in rare cases complications, such as nerve damage, may cause the legs or bladder to stop working properly. It is important to tell your doctor and nurses immediately if you experience problems.
It can take up to six weeks to get over the general pain and tiredness following your operation.
Stitches
You will have stitches to repair any cuts or incisions made during your operation. Deep stitches beneath the skin will dissolve and do not need removing. Stitches or clips used on your skin will be removed 5-10 days after your operation. You will be given an appointment to have your stitches removed before you leave hospital.
Your stitches may be covered by a simple adhesive dressing, like a large plaster. When you wash, be careful not to get your dressing wet. After having your stitches out, you will not need a dressing and will be able to bath and shower as normal.
Rehabilitation
Your medical team will want you to get up and move about as soon as possible. This is because not moving can increase your risk of deep vein thrombosis and movement helps to speed up the recovery process.
After your operation, a physiotherapist will monitor your specific needs and help you to safely regain strength and movement. Exercising the spine as instructed will help you recover quicker than if you stay inactive.
Getting home
You will be able to go home one to four days after your operation. How long you have to spend in hospital depends on the type of surgery you had (recovery is quicker after a microdiscectomy) and your individual state of health.
It is important that you take things easy at first. Some help at home is usually needed for at least the first week after surgery. Avoid heavy lifting, awkward twisting and leaning when you do every day tasks.
Work
When you can go back to work depends on how you heal after surgery and the type of job you do. Most people return after four to six weeks if their job is not too strenuous. If your job involves a lot of driving, lifting items that weigh over 5kg or potentially violent situations, you may be off work for up to 12 weeks.
Driving
Before starting to drive again, you should be free from the effects of any painkillers that may make you drowsy. You should be comfortable in the driving position and able to fully control your car, including being able to do an emergency stop without it causing you any pain. Most people feel ready to drive after two to six weeks, depending on the size of the operation.
Some insurance companies do not insure drivers for a number of weeks after surgery, so check what your policy says before you start to drive.
Repeat surgery
After back surgery, 20-30% of people experience recurring symptoms. These can be from a weakened spine or another slipped disc, formation of new bone or thickened ligament. Other treatments, such as physiotherapy, will be tried in the first instance, but further surgery may be needed in some cases.
When to call your doctor
Call your doctor if:
- there is leaking fluid or redness at the site of your wound,
- your stitches come out,
- your dressing becomes soaked with blood.
- you have a high temperature (fever) of 38°C (100.4°F) or above,
- you have increasing pain or numbness in your legs, back or buttocks,
- you cannot move your legs,
- you cannot urinate or have lost control of your bladder,
- you have a severe headache,
- you experience a sudden shortness of breath (this could be a sign of pulmonary embolism, pneumonia or other heart and lung problems).
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