In surgical vocabulary an -ectomy is the removal of a body of tissue, organ, or structure, and in the case of a discectomy this is the removal of an intervertebral disc. A partial discectomy is the excision and removal of a fragment of disc, such as the herniated material or disc bulge causing nerve compression and back pain but this type of back surgery procedure may sometimes be referred to as a discectomy which can cause confusion. Traditional back surgery for a herniated disc is an open discectomy where an incision is made in the back, just above the problematic disc, and the surgeon moves muscles, nerves, and ligaments aside to gain access to the herniation and remove the disc, severing the muscles and ligaments in some cases.
An open discectomy is performed under general anaesthetic and takes around an hour depending on the patient’s size, health status, the severity of the herniation, and other variables. Lee (2009) found that minimally invasive microdiscectomy took an average of 45.8minutes, compared to 73.8minutes in traditional open discectomy surgery. The shorter operating time is not the only benefit of minimal access back surgery as the procedure, usually, causes significantly less trauma to the back’s muscles, nerves, and ligaments, shortens recovery time, reduces the risk of infection and severe blood-loss, and makes scarring, both internal and external, less likely and/or noticeable.
Some patients may not be candidates for minimal access microdiscectomy due to other complications, larger body mass, the necessity for spinal fusion, and previous failed back surgery. Patients should ensure that they discuss their options with their physician prior to scheduling any procedure and that they are comfortable with the likely effects of surgery and their chances of recovery. Around 85-90% of patients undergoing discectomy achieve resolution of their symptoms, with pain often dissipating fairly rapidly, and numbness and weakness taking a little longer to resolve. There are many beneficial actions to take after a discectomy, such as not smoking, avoiding bending and stretching activities for a period of time, and ensuring correct nutrition and hydration. Patients are likely to be given an exercise regime by a physical therapist to promote their recovery.
The video shown is of a discectomy on the neck – in this case the incision is made on the front (anterior) side of the body.
Traditional Open Discectomy
During this back surgery procedure the patient will be lying face down after being turned onto their back following the administration of general anaesthetic. The surgeon makes a 2-3cm incision above the spine in the area of the disc pathology and then dissects the spinal muscles to gain access to the lamina covering the spine. A small piece of the lamina is then removed (a laminotomy) or, if several discs are being decompressed a large section of this ligament is excised (a laminectomy). If a large portion of the lamina is removed during an open discectomy then the patient may incur slippage and curvature of the spine (kyphosis) without a stabilization procedure such as spinal fusion. A laminoplasty (a hinge-like formation) may be possible to maintain the intervertebral height, or a laminotomy in some cases where only a small portion of the ligament is removed to allow access.
After removal of the covering ligament, the surgeon will be able to see the spinal nerves exiting the spine and locate the herniated disc causing the nerve compression. The disc fragment or the complete disc will be removed according to the degree of compression occurring. An open discectomy also allows the surgeon the access to remove osteophytes which may be adding to compression of the spinal nerves. This may be difficult in minimally invasive spine surgery where access is restricted to a smaller area. The surgeon may then perform a spinal fusion procedure and/or further discectomy at another level if necessary and close the incision and apply a surgical dressing.
Open Discectomy Risks
As the open traditional discectomy takes longer and exposes more of the internal tissues of the body there is a higher degree of infection risk in comparison to minimally invasive back surgery. Patients undergoing any surgical procedure should watch out for the development of a fever, tenderness and inflammation at the site of the incision, any fluid leakage or change in appearance of the incision, and acute headaches or stiffness of the neck which could indicate an infection that has spread to the spinal fluid. Any such symptoms should be immediately reported to a medical doctor and investigated as prompt action can prevent permanent disability and death from an infection such as spinal meningitis.
After a Discectomy
When undergoing back surgery for nerve pain due to disc compression, patients may come round from their anaesthetic with complete resolution of leg pain and sciatica symptoms. In most cases however, where the compression has existed for some time, it will take a little longer for the results to become clear and patients are likely to notice an improvement in symptoms over a number of weeks. Analgesic medications may be prescribed to alleviate the pain associated with the incision and tissue trauma. Patients are usually monitored in the hospital overnight and discharged the next day. A review by Lee (2009) found the average stay to be 0.9 days for those undergoing minimal access microendoscopic discectomy, and 3.8 days for the conventional open method. Complications were also found to be lower in this study in association with minimal access discectomy (4%) as opposed to open discectomy (10.3%).
In most cases patients are encouraged to become mobile again as soon as they can after surgery, even if this is only a little walk to the chair in their hospital room, or to the bathroom. This is in order to reduce the risk of thrombophlebitis occurring and to prevent the patient from stiffening up. A gradual increase in gentle exercise is recommended with patients advised to take longer walks over successive days to aid the recovery process. The use of a corset or brace is advised for some patients, particularly those who are at risk of spinal hypermobility during the healing process including those who have had a discectomy and fusion procedure. Any activity which involves twisting or bending the back is usually to be avoided and patients will be cleared for other activities, such as driving, sexual activity, and exercise other than walking after their follow-up appointment (usually set for two weeks after back surgery).
Risks and Benefits of a Discectomy
A recurrent disc herniation is the major cause for concern with this type of surgery as 10-15% of patients will require additional spine surgery to remove another disc fragment following herniation. Those patients who have had nerve compression for some time prior to back surgery are less likely to achieve a full resolution of their symptoms, with the success of the procedure around 85-90%. Discectomy has all of the usual risks associated with back surgery including:
- dural tear
- spinal fluid leakage
- muscle and nerve damage
- failure of the surgery to resolve the symptoms
Patients who undergo an open discectomy will usually incur larger degrees of tissue damage, experience more blood-loss, and take longer to get back on their feet than those having minimally invasive back surgery. If some of the back muscles were severed to allow access to the spine during the procedure then recovery is liable to take longer and be more painful as the spine settles down and the other back muscles compensate for the loss. Scarring is more apparent with open discectomy with a larger incision externally, and potential fibrosis internally where ligaments, nerves, and muscles were impacted by retractors and other instrumentation.
Patients with clear-cut compression of nerves due to herniated or bulging disc material are excellent candidates for a discectomy and will likely experience a significant relief from symptoms once the offending material is removed by this type of back surgery. Relief may be felt instantaneously if patients undergo the procedure under a local anaesthetic, although symptoms of numbness and weakness are likely to take a little longer to dissipate as the nerve heals over time. Inflammation from tissue trauma may need to reduce before experiencing the full effects of the procedure for some patients and they may be prescribed NSAIDs to achieve this more quickly.
Minimally-invasive back surgery carries approximately a 4% risk of infection, with other risks including transient dysaesthesia, and nerve root irritation, although incidence of these in two reviews of a small number of patients were 2.3% (Ahn, 2004), and 1.1% (Hoogland, 2008) respectively. None of the patients in these studies had permanent nerve damage. There is, as always, a risk that the surgery will not correct the symptom the operation was performed to address. Ahn (2004) found that 81.4% of patients undergoing a minimal access lumbar discectomy had an excellent or good outcome.
Watch this video that explains the risks and complications of spine surgery.
Patients may be able to undergo a more modern procedure called an endoscopic discectomy if they require back surgery on only one level and they have no other complications. If a patient requires attention at several spinal levels and will likely need spinal fusion then an endoscopic discectomy may not be appropriate. In some cases a surgeon may commence a minimally invasive procedure only to discover that an open back surgery is necessary due to complications. Some patients with disc herniation at more than one level may be able to have minimal access surgery using a series of small incisions above each problematic disc.
An endoscopic discectomy involves a smaller incision being made above the herniated disc and a tubular retractor inserted to gradually nudge aside the muscles and nerves allowing access to the lamina. The surgeon will use a number of small, specialized instruments alongside an endoscope (a tube with a camera on the end) to perform the surgery. The endoscope’s camera will project a live image onto the monitors in the operating theater to allow the surgeon to visualize the field without having to open up the back in the same fashion as traditional back surgery. If several discs are being operated on then small sections of the lamina over each disc can be removed to provide access. By removing smaller portions of the lamina minimal access discectomy can allow the surgeon to forego the requirement of a spinal fusion procedure as necessary with most laminectomies. The intervertebral height may be maintained more successfully with the majority of the lamina left intact and problematic kyphosis (spinal curvature) can be avoided.
Benefits of an Endoscopic Discectomy
An endoscopic discectomy can minimize the trauma to the muscles and nerves and does not require the muscles to be dissected from the bone. Complications of muscle weakness in the back, and nerve damage, are therefore reduced with minimal access discectomy. The operation may be conducted under a local anaesthetic rather than general anaesthetic which allows for a quicker recovery and return to activity, reduces the risks of thrombophlebitis, and has less risk of respiratory or cardiac complication or allergic reaction to the anaesthetic. For some patients the open procedure is, however, necessary to increase the chances of a resolution of their symptoms and, although the faster recovery time from endoscopic surgery is attractive their surgeon may consider the minimal access procedure inappropriate.
Patients with radicular pain, weakness, numbness, loss of fine motor skill and strength, and paraesthesias in the arms and neck are candidates for discectomy where the symptoms are a result of a herniated or degenerative disc. The majority of patients will have tried more conservative treatments initially, although some patients with acute loss of motor control, weakness, numbness, and severe pain may be rushed into surgery to prevent permanent nerve damage. Conservative treatments, such as the use of analgesics and NSAIDs, complementary therapies, and physical therapies are usually tried for three to six months before back surgery is considered appropriate.
Prior to a discectomy, patients will undergo a series of diagnostic testing, such as X-Rays and MRI scans, to ascertain the level where the problems exist and the possibility of discectomy relieving those symptoms. Selective nerve root blocks (SNRB – pronounced snerb) may also be used to clarify which nerves are causing the symptoms such as radicular pain or numbness. Patients who have suffered acute trauma to the neck or back, through a whiplash or contact sports injury perhaps, are likely to be candidates for immediate surgeries such as a discectomy if the damage may cause permanent nerve pathology. The presence of osteophytes (bone spurs) in the spinal column, or vertebral slippage may affect the available treatment options and patients with back pain should discuss all of the appropriate procedures with their physician prior to back surgery being scheduled.
Anterior Cervical Discectomy
Those with herniated disc in neck may also be candidates for a discectomy and may undergo a slightly different procedure called an anterior cervical discectomy. This operation accesses the spine from the front of the neck and, therefore, carries a number of unique risks associated with the complex region of nerves, blood vessels, thyroid, larynx, and other cervical spinal structures. The anterior approach is the most common type of discectomy performed for the cervical spine however, as the curvature of the neck makes herniated material most likely present at the front of the spine rather than the back as with lumbar disc herniation.
A back surgery fusion may be required which could necessitate a bone graft made up of the patient’s own bone, thereby adding another procedure to the back surgery itself. Obese or heavily overweight patients may not be able to have minimal access discectomy surgery as the instrumentation might not be able to penetrate the tissue of the back sufficiently to reach the vertebral column; an open procedure is often preferred although this carries with it the associated risks of respiratory complications that in themselves are more likely in larger patients.
Pre-Spine Surgery Testing
Patients will also be tested for signs of infection immediately before any scheduled surgery as this will most likely prevent the procedure from taking place. Pre- and post-operative antibiotics may be given if there is concern over the possibility of infection. Guidance on the cessation of medications will be given prior to surgery, and patients should ensure that any herbal or nutritional supplements they are currently taken are known to their doctor so that advice can also be given on these (some anti-inflammatory remedies may also be blood-thinners, fish oil for example). Patients are discouraged from smoking prior to, and after, back surgery as this can severely impair their recovery, particularly in the cases where patients require spinal fusion after a discectomy.