Imagine that you are working in the OR when the armboard on which your patient’s left arm is secured falls during repositioning. You and another nurse immediately support the patient’s arm, and the operation proceeds uneventfully. However, the patient later complains of left arm numbness and pain. An electromyography/nerve conduction velocity study show acute denervation of the left C5-6 nerves. Later inspection of all armboards in the OR reveals damaged brackets to all of the units.¹

Peripheral nerve injuries can occur during any type of surgery. They can occur for many reasons — faulty equipment, improper positioning — and sometimes for no apparent reason at all. A team approach helps to prevent peripheral nerve injuries during surgery. Nurses caring for surgical patients before, during, and after surgery and nonsurgical procedures, such as endoscopy, must understand proper positioning techniques to ensure the best possible outcome for the patient.

How often do these injuries occur? We don’t know for sure. Patients never report some of them. Those that are reported may be treated, referred to a specialist, or resolved by themselves over time.

One way to track peripheral nerve injuries is through a cumulative report of injuries that end up in the legal system. The American Society of Anesthesiologists (ASA) closed claims database http://depts.washington.edu/asaccp/ASA/index.shtml is a collection of case summaries from the closed claims files of 35 insurance companies. The most recent study of nerve injuries related to anesthesiology, which uses numbers from the database, shows the significance of the problem. In this study, 670 (16% of 4,183) claims are for anesthesia-related nerve injury. This is second only to death (32%) in the number of cases that were settled, and ahead of brain damage (12%), third.² Table 1 shows the distribution of claims for nerve injury. (The data includes anesthesia- and surgery-induced nerve injuries as well as positioning injuries.)

Once the problem was documented, it was apparent that a multidisciplinary approach was needed. In 2000, the ASA assembled a task force of anesthesiologists, nurse anesthetists, anesthesiology assistants, perioperative nurses, surgeons, and emergency medicine physicians to develop a practice advisory.³ The practice advisory includes recommendations for pre- and postoperative assessment, positioning, padding, and equipment. The upper extremity recommendations are summarized in a sidebar.

How do these injuries occur?

The five primary mechanisms for perioperative neuropathies are stretch, compression, generalized ischemia, metabolic derangement, and surgical section. As little as a 10% to 15% elongation of a peripheral nerve is enough to cause important alterations in vital physiologic processes, compromising the condition of the peripheral nerve.⁴ Patients may arrive for surgery with preexisting metabolic derangements and subclinical neuropathies. The metabolic derangements that can play a role in peripheral neuropathies include diabetes, pernicious anemia, alcoholic neuritis, atherosclerosis, drug exposure, heavy metal exposure, and infectious diseases, such as polio.

Getting ready

The position for operation is initially determined by the procedure to be performed, the surgeon’s choice of approach, and the anesthetic considerations. In addition, the operating team as a whole needs to consider the patient’s preoperative history and physical examination. This can include the patient’s age, height, weight, general health status, activity level, mobility restrictions, cardiopulmonary status, preexisting diseases, neurological status, presence of implants, and known areas of discomfort.

Certain preexisting risk factors may affect positioning strategies, including obesity, diabetes, paralysis, and advanced age. Many positions can be tested before surgery in awake patients. Nurses should gently abduct, adduct, flex, extend, and rotate the upper extremities into the positions the patient may experience, checking for resistance and pain.⁷ It’s essential to check all positioning equipment for proper functioning.

Preventing harm

Brachial plexus and ulnar neuropathies are the most common upper extremity injuries. Some brachial plexus injuries not directly related to positioning include those caused by median sternotomy in cardiothoracic procedures and those related to brachial plexus blocks by the anesthesia provider. Shoulder braces have been implicated in numerous brachial plexus injuries. If possible, avoid using shoulder braces by using a secured “bean bag” and/or ankle straps to hold the patient in place on the operating table instead. If shoulder braces must be used, they should be placed over the acromion processes and not over the muscles and soft tissues near the neck. The shoulder brace should not be used if the arms are to be extended on armboards.

Ulnar neuropathies are the most reported neural injuries, and arguably the most misunderstood. The ulnar nerve passes around the medial epicondyle of the humerus at the elbow, and under the retinaculum of the cubital tunnel. The nerve runs very close to the surface at the elbow, which leaves it vulnerable to injury. Perioperative ulnar nerve injury is often ascribed to malposition of the elbow, with the ulnar nerve being compressed on a hard surface during surgery or stretched in some fashion. Today, virtually all armboards have foam rubber padding (such as “eggcrate”) or gel pads.

A great deal of controversy exists in the literature on whether arms should be pronated or supinated or remain neutral. Pronation, placing the hands face down on the armboard, is not recommended in the current literature. Generally, either supination or neutral position is recommended as long as the position does not put direct pressure on the ulnar nerve at the elbow. When tucked at the sides, the arms should be secured and padded in neutral position to ensure that there is no pressure on the medial epicondyle from the edge of the OR bed.

Positioning, however, may not be the primary culprit in the development of ulnar neuropathies. A study on ulnar neuropathy with a sample size of over 1 million consecutive patients suggests that perioperative ulnar neuropathies are not associated with general anesthesia or intraoperative positioning. Overweight or underweight men with long hospitals stays are particularly susceptible to ulnar neuropathies.⁵ In another study www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9915312&dopt=Abstract, patients at high risk for ulnar neuropathy are men 50 to 75 years old undergoing surgery a variety of procedures, independent of padding and positioning.⁶

Radial and median nerve injuries are much less common. Damage to the radial nerve is usually due to prolonged pressure where the radial nerve spirals around the humerus. Injury is not usually due to positioning, but can be caused by a surgical tourniquet. However, compression of the median nerve is the cause of carpal tunnel syndrome. While there have been reports of median nerve injuries during surgery, the incidence is very low.²

Doing it right

Patients in the supine position should not have their arms abducted on armboards more than 90 degrees from their body. The ASA Practice Advisory http://anesthesiology.med.miami.edu/Library/mm_articles/68.pdf says that prone patients may tolerate abduction greater than 90 degrees, but that care providers should exercise caution in patients with preexisting thoracic outlet syndrome.³ The elbows should neither flex more than 90 degrees nor “straighten” more than the patient is comfortable with or when resistance is felt. A study www.ncbi.nlm.nih.gov/entrez/query. fcgi?cmd=Retrieve&db=PubMed&list_uids=12131106&dopt=Abstract using awake volunteers evaluated the impact of various arm and neck positions on the upper quadrant nervous system by measuring the range of motion that is achieved before pain occurrs.⁴ The findings suggest that —

• Adding fixation (as in shoulder braces) significantly reduces the range of motion even when the braces are positioned as advocated. If shoulder braces must be used, using a beanbag under the lower area of the body can help unload the pressure against the braces. The pressure of the braces should be controlled and monitored regularly.
• Simultaneously adding positions that load the nervous system can cause a greater impact than that of each individual position. An example would be abducting the arm, flexing the head away, and supinating the arm at the same time.
• Similarly, relaxing a neighboring region provides a neutralizing effect and allows for unloading the nervous system.
• Patients differ widely in their reactions to elongation of the nerve bed, possibly due in part to preexisting subclinical neuropathy. Triggering a preexisting subclinical neuropathy is considered a possible mechanism for development of perioperative ulnar neuropathy. This has implications for both prevention and medicolegal justification.

If the patient is to be positioned supine with the arms tucked at the sides, the arms should be in a neutral position, palms facing the body, fingers straight. If the draw sheet is used to hold the arms in place, the sheet should go over the arms and then under the patient, but not under the mattress of the OR bed. Tucking the sheet under the mattress pulls the arms posterior and can cause additional stretch on the brachial plexus. The arms are also more likely to droop over the edge of the bed and be compressed against the edge of the bed, injuring the radial, ulnar, or median nerves.

Patients positioned in the lateral decubitus position should have a chest roll under the dependent thorax just caudal to the axilla. Calling this an axillary roll is a misnomer because placing it in the axilla will displace the head of the humerus against the brachial plexus, causing both stretch and compression injuries. The chest roll should lift the thorax and help prevent compression of the dependent neurovascular bundle. A pillow should be used to support the head, keeping it in line with the cervical spine. This neutral position helps minimize the stretching on the dependant brachial plexus. The dependant (down) arm should be positioned at an angle of less than 90 degrees. The nondependent (up) arm can be placed in a well-padded holder and positioned so as to minimize stretch on the brachial plexus.

Taking action

As with any nursing intervention, the first step is assessment. Many of the factors to assess have been listed in the “Getting ready” section. With the risk factors in mind, the nurse checks the patient for range of motion and positions of discomfort that may be encountered during surgery. Communicate with the patient about any positioning concerns he or she may have.

Develop the positioning plan in conjunction with other members of the surgical team. There must obviously be a plan for the patient’s positioning, but the perioperative nurse must also plan for additional padding, supports, personnel to help move and position the patient, and extra sterile drapes if needed. Proper planning helps ensure the patient’s comfort and safety, and having everything ready reduces the time the patient must be anesthethetized.

Implementation is a continuation of the planning step. The patient’s individual plan should be carried out in a smooth but timely manner. The nurse’s coordination with the surgeon and the anesthesia provider is critical to ensure that the patient is optimally positioned. All positioning aids and padding should be applied, and the patient should be secured so that unintended movement will not occur.

The evaluation of the patient should be ongoing throughout the surgical procedure, with a final assessment at completion. Unlike alterations in skin integrity, nerve injuries are not immediately visible. The patient can be assessed for proper positioning during the procedure, but evaluation of nerve function must wait until the immediate postoperative period.

Perioperative documentation should include the nursing diagnosis, for example, “risk for peripheral sensory alteration,” and an appropriate goal or expected outcome statement, such as “The patient will maintain normal peripheral sensory integrity”⁷ or “The patient is free from signs and symptoms of injury related to positioning.”⁸

If a patient complains of a neurological deficit before, during, or after surgery, the nurse needs to document it. Be sure to include the specific sensory and motor deficits, time of onset, and any subjective sensations like stinging, burning, or sharpness. Neurology should be consulted as soon as possible to assess the patient and start treatment, if indicated.

Staying out of court

Defending a legal case involving a nerve injury can be difficult. Patients may not remember exactly when their symptoms began and may assume that the symptoms are directly related to their surgery. And many claims are paid even when the standard of care <www.nursinglaw.com/ornurse4.htm> is met. The study of legal claims involving anesthesiology-related nerve injuries found that payment was made in 47% of the ulnar nerve injury claims in which care was appropriate. Payment was even made in 50% of the ulnar nerve damage claims in which the patient was awake or sedated during regional anethesia and the surgery was performed on the lower body.²

The patient’s attorney often uses the theory of res ipsa loquitor <www.njlawyers.com/RESIPSA.pdf>, “the thing speaks for itself.” If a patient goes into surgery without an apparent nerve injury and returns from surgery with an injury or develops one later, the assumption is often that someone must have done something.

Good documentation before, during, and after surgery will help avoid unnecessary legal action During one study, two patients considered legal action until they (and their attorneys) were shown documentation that the patients had no symptoms until postoperative days four and six. They decided not to pursue their cases.⁶

Proper positioning is essential for a safe and successful surgical procedure. The entire surgical team must work together to minimize the chances of an intraoperative injury.