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Procedures Risks & Benefits

Benefits

Spinal surgery or interventions (such as injections) when performed correctly for the right indications (reasons and patient selection) can be life changing and markedly improve quality of life, improve function and reduce reliance on medications and need for aids and the support of others to perform activities of daily living.

When the function of the spinal cord or nerve is impaired such as balance, bladder or bowel function, the ability to walk (e.g. leg giving way or foot drop) or usefully use the upper limb (arm weakness) the decision is often straight forward as surgery is more often seen as a necessity and recommended.

However, when pain and mild sensory disturbance alone are the reason for considering surgery the decision making is more involved. Broadly speaking, removal of pressure from compressed spinal nerves can improve pain not just as experienced in the back or neck but also the pain experienced in the arms (when the nerve is in the neck) or in the legs (when the nerve is in the back). This pain is often difficult to control with simple measures. Surgery for back pain or poor alignment tend to have less reliable results. 

It is also important to bear in mind that in a minority of cases, the pain or functional result can be considered to be worse or not improved. Occasionally, the problem can return after being addressed at initial surgery e.g. a disc prolapse can recur. This all needs to be considered when deciding on surgery for more elective reasons.

Complications and risks:

There is a great fear of complications from spinal surgery. Much of it is irrational or overplayed and some of it justified - in any case, the decision making and discussion of risks is important and deserves time and respect. Experienced and technically accomplished surgeons will have complications in their career if they perform enough operations - the key is being realistic about the relative chance of complications, what they would mean for the patient and how to manage them, should the procedure be recommended.

The common fears and discussion regarding "paralysis" is not grounded in science or evidence. It is theoretically possible occuring very rarely in cervical spine surgery and more commonly, but still rarely, in thoracic spine surgery but in surgery performed below the L2 level it is theoretically impossible in individuals with normal spinal development. Please see the section on spinal anatomy to understand further, but below the Conus Medullaris the fibres in the spinal sac are not spinal cord fibres that produce the dysfunction commonly associated with paralysis. It is much more common to have temporary or sometimes lasting dysfunction to 1 or 2 nerves responsible to sensation and function to a single limb. Often the damage to the nerves is not the conduction fibres that transmit information themselves but the nerve skin (dura) that contains the fluid that overlies the information conduction fibres - this is known as a dural tear. The priority becomes containing the spinal fluid from leaking out from the tear as it can compromise the pressure higher up in the spinal cord and brain, prevent wound healing and sometimes lead to inflammation and sticking together of the nerve fibres (arachnoiditis). 

Death from elective spinal surgery, as opposed to emergency surgery, is very rare in healthy individuals who have been appropriately screened and prepared for general anaesthesia and surgery. Nonetheless medical complications can rarely occur such as heart rhythm abnormalities, severe allergies, sudden problems with breathing, severe blood pressure swings, strokes and so on that can threaten life when not treated promptly. Again this is another reason that the informed consent process deserves respect as there is a small risk (for health individuals) with each general anaesthetic.

Wound problems range from a cosmetic issues such as broad and thick scar for posterior neck surgery to more serious issues such as Infection. Infection in spinal surgery is relatively uncommon with procedures performed from the front of the spine (such as in anterior lumbar or cervical surgery) and extremely rare with injections but more common in posterior (involving open incisions on the back, approached from behind) surgery particularly with larger scale and longer operations. As a general rule, the less invasive the procedure is and the less muscle and skin manipulated, the less risk of infection - for example it is extremely rare to have infections related to injections but relatively more common to have infections for large posterior surgical wounds. Most wound issues generally are related to the body's reaction to movement and pulling apart required to do surgery of the different soft tissue layers - the most common issue in deep wounds is prolonged ooze followed by superficial infection and rarely, deep infection. The infection rate is higher with not just related to the type of procedure and location (e.g. higher in operations to remove the coccyx) but also certain risk factors such as current smoking, diabetes, malnutrition, circulatory problems, steroid use, skin conditions, previous radiotherapy to the area and certain medications (such as those used to treat rheumatoid and inflammatory arthritis conditions) amongst others.

Two relatively common wound problems after posterior cervical or lumbar procedures are (1) Seroma and (2) Suture granuloma also known as 'stitch abscess'

(1) A seroma is a collection of sterile wound fluid that forms under the skin of the surgical wound in the first 3 or so weeks after surgery. It develops due to slow and delayed internal healing of the different layers between the skin and the spine (i.e. the fat, muscle and fascia), particularly where structures have been moved or removed. Inflammation from surgery makes the tiny bloods vessels more leaky than usual and causes accumulation of fluids around the wound bed due to excess deposition and failure of the leaky vessels to transit the fluid away effectively. Generally, the vast majority of seroma resolve as the inflammation settles without the need for any intervention (the body absorbs it and shrinks down the space as the wound contracts) and are not harmful but can be an uncomfortable or an annoying swelling. Pressure such as in the form of a binder can be useful. Occasionally, needle aspiration can be beneficial and considered where resolution is very slow - it is very rare to require surgery for this.

(2) A suture granuloma or a stitch abscess is a (non-infective) superficial wound issue along the suture line where the majority of the wound is healed but there is a delayed reaction (often between 3-6 weeks) where an isolated part of the wound can become inflammed, open up or some suture material can be expressed (~2-4%). The reason that they occur is that the absorbable suture is a foreign body designed to be broken down by the body's immune cells - while the suture will always be seen as a foreign body, like having a splinter in the skin, some immune reactions can be more vigorous in some individuals than others to the suture causing an inflammatory reaction resembling infection but without any micro-organisms (a sterile abscess). Occasionally, surrounding cellulitis develops. Generally, these are treated topically with wound dressing and removing any extruded suture material presenting itself at the surface in an aseptic fashion and resolve themselves.

Bleeding can present problematically in three different ways in spinal surgery. It can present as a generalised ooze that can lower the blood circulating in the system and also increase the risk of infection. It can present as a large blood clot that can place pressure on the nerves or wounds or in the neck can compromise the airway and threaten life. Finally, it can cause sudden life threatening bleeding during procedures in close vicinity to major blood vessels, particularly in anterior lumbar or thoracic surgery.

There are then more common and minor complications that are emphasized according the procedure discussed and the individual concerns. Some example of risks that are commonly discussed in common spinal procedures (and usually self-limiting) include:

In injections - changes due to hormone swings (including sleeplessness), muscle aches and sunburn type sensitivity on the skin.

In anterior neck surgery - changes in swallowing, voice, ongoing facet pain.

In anterior lumbar surgery - changes in the gastrointestinal function, hernia and subtle changes in leg circulation/sensation or sexual function (retrograde ejaculation).

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