This post is provided courtesy of K. T. Weber, Drexel University College of Medicine Class of 2013:
When a patient goes under anesthesia, a highly trained team of people take over and monitor the body. This team controls breathing, circulation and many other processes, filling in very well for the patient’s brain… however, there is one function that cannot be replicated by the anesthesia team: movement. In order to undergo surgery, a patient must have their muscles relaxed, and therefore will not move away from sore or painful spots. It is normal for people to fidget, rearranging their weight to more comfortable positions, which helps to prevent bed sores (decubitus ulcers) as well as preventing minor nerve compression.
Decubitus (or “pressure”) ulcers can be a devastating complication for patients who undergo very prolonged surgeries – Superman actor Christopher Reeve actually died from complications associated with an infected pressure ulcer. Fortunately, these wounds are very rare in patients who are only temporarily relaxed for surgery, and there are many precautions in place to prevent this from occurring.
However, minor nerve injury is still possible! One of the less commonly discussed side effects of having surgery, this minor nerve injury can be very disconcerting and affects a surprisingly large number of people
Nerve damage can occur in several forms based on the type and cause of injury:
The mildest form of nerve injury is neurapraxia, where the myelin sheath and support cells around the nerve are damaged (frequently by excessive pressure or ischemia), leading to poor signal conduction along an otherwise unharmed nerve. Neurapraxia improves on it’s own with time as the myelin sheath regenerates, and does not directly involve injury to the axon of the nerve.
Neurotmesis, the most severe type of injury, occurs when a nerve is lacerated, over-stretched or very badly crushed, and the two ends of nerve are actually separated from each other. These nerve injuries will not get better on their own without nerve graft repair surgery.
Axonotmesis is an intermediate type of nerve injury, where the nerve is damaged (often by crushing) but the support cells around the nerve are intact and aid regeneration, so (slow) spontaneous recovery is possible.
The most common symptom of compressive nerve injury is numbness or pain. The tingling, pins-and-needles feeling of hitting one’s funny bone is a classic example of nerve pain. Many patients who have undergone surgery and are held in one position for an extended period of time may wake up with areas on their skin that feel extra sensitive, like a sunburn. It is understandable to be concerned by waking up with hyperaesthesia, or pain in response to something that wouldn’t normally be painful! Weakness and uncoordination is less common, and only occurs after more severe or prolonged nerve compression during surgery.
The good news for patients who wake up with an unusually sensitive area or some numbness after having surgery is that this minor nerve damage tends to improve rapidly. Neurapraxia resolves as the swelling and bruise around the nerve decreases and the cells that help conduction recover, sometimes as quickly as a few hours, sometimes as slowly as several months. If necessary, non-steroidal anti-inflammatories, other medications for neuropathic pain and splinting can help treat the symptoms of mild nerve damage. Even more severe forms of nerve injury can recover with time – peripheral nerves grow back around 1mm per day! In the most extreme cases, without the potential to regenerate on their own with time, nerve graft repair can be discussed as an option.
Watch a video presentation on nerve injury and repair:
Of course, an ounce of prevention is worth a pound of cure. The skilled members of the operating room staff take extensive measures to protect their patients with adequate padding and careful positioning.