Positioning the patient for a surgical procedure is the shared responsibility of the entire OR team. A patient under anesthesia loses some or all of his protective reflexes and can't adequately feel or express a painful sensation that would reveal a potential nerve injury. Proper positioning of the patient is a simple and effective method to help prevent intraoperative neural injury. This article will review the most commonly used surgical positions and methods to protect your patient during an operative procedure.
Supine
The ulnar nerve is the most frequently injured nerve in the perioperative period.1 It's theorized that damage occurs secondary to compression of the nerve at the level of the elbow. When in the supine position, supination of the patient's forearm minimizes compression of the nerve against the operating table. Furthermore, ensuring that the elbow is adequately padded with either foam or commercially prepared elbow pads also helps insulate the ulnar nerve.
The patient's arms in the supine position, or any surgical position, should never be abducted greater than 90 degrees. Extending the arms further than this can stretch and injure the brachial plexus. The brachial plexus is second only to the ulnar nerve in frequency of perioperative nerve injuries and is also vulnerable to injury from other maneuvers. Allowing the arms to extend dorsally, or fall below the rest of the body, especially in conjunction with turning the patient's head, can damage the plexus. The patient's shoulders should remain parallel with the table and the arms should be secured to prevent them from falling off the table during the procedure.
The patient's lower extremities are also of concern in the supine position. The patient shouldn't have his legs crossed because this may cause pressure on the sural nerve of the upper leg and the peroneal nerve of the lower leg. His knees and hips should be slightly flexed to reduce stress on the back and abdomen. Allowing the patient to place himself in a comfortable position prior to anesthesia may prevent postoperative discomfort.
Lithotomy
There are many concerns to address when placing a patient in the lithotomy position. The patient can be injured while being placed in and out of the position, as well as while in the position.
When placing the patient in the lithotomy position, both legs should be moved in unison to avoid overstretching the nerves of the lumbosacral plexus. Once the calves are in the stirrups, the thighs shouldn't be flexed more than 90 degrees. The legs should be padded so that they don't touch the poles of the stirrups directly. Compression along the medial calf can damage the saphenous nerve, which will result in weakness below the knee postoperatively. If the legs are placed inside the stirrup poles, compression of the lateral aspect of the calf will damage the peroneal nerve.
Although uncommon, a patient's hand may suffer a crush injury if caught between moving parts of the OR table. This can happen when returning the foot of the OR table to the horizontal position at the end of the surgical case. Always ensure that the patient's hands and fingers are clear of all moving parts when returning the table to its original position.
Compartment syndrome has been reported in conjunction with the lithotomy position.2,3 Extreme knee flexion, or leg holders that lie underneath the calf, can decrease arterial flow and venous return. Suspension leg holders are preferable to those that cradle the calf because the latter can transmit pressure to the muscle and fascia. Compartment syndrome is associated with prolonged surgical duration in the lithotomy position.
Lateral decubitus
The lateral decubitus position can be used for thora-cic and renal surgery, as well as some orthopedic procedures such as shoulder surgery. For the purposes of this discussion, the side of the patient that lies on the OR table will be referred to as 'dependent'. The side of the patient not touching the OR table will be referred to as 'nondependent'.
Maintaining body alignment is crucial to proper positioning. The spine, head, and neck should all be in the neutral position. Blankets may be necessary to support the head. When the head is in its final position, make sure the dependent ear isn't bent or kinked.
The axillary vessels and brachial plexus of the dependent shoulder can be compressed. A roll should be placed beneath the ribs just below the axilla to relieve pressure on the brachial plexus and axillary vessels. Although often called an axillary roll, the roll shouldn't be placed in the axilla.
The upper arm should be placed on a padded stand, neutral in relation to the shoulder and 90 degrees from the body. Both arms should be secured so that they don't move during the surgery. The upper arm should never be abducted higher than the shoulder or placed so that it extends above the head.
Once rolled laterally, the dependent leg should be flexed at the knee. This will provide a stable base for the patient. Blankets, pillows, or some other padding should be placed between the knees to prevent pressure on the peroneal nerve. The nondependent leg should be further supported to prevent excessive adduction of the leg and to decrease the weight of the superior leg against the dependent leg.
The patient is secured in the position using a variety of methods, such as pillows, braces, or "bean bag" devices. When securing the patient to the table, the belt must be placed over the patient's iliac crest. If it's placed across the hip, avascular necrosis of the superior femoral head may occur. Also, placement of a strap or belt across the thorax can prevent optimal chest expansion.
Prone
The prone position and its variations-the jackknife and sitting-prone positions-are used mainly for spinal procedures and certain types of intracranial procedures. Regardless of the type of prone position used, certain principles remain constant.
The patient should be turned with the help of the entire OR team (at least four team members) in unison. Make sure the head is in-line with the rest of the body as the patient is being turned. Once the patient is prone, excessive rotation of the head and neck should be avoided. Ideally, the head should be maintained in the midline position. The neck should be in neutral alignment with the spine and head. Eyes should be free and clear of any pressure; compression of the eyes can cause a corneal abrasion. Also, pressure on the eyes is a possible etiology of postoperative blindness, a rare but devastating complication.
The arms can be placed either at the patient's sides or supported along the head. If the arms are tucked at the sides, they should be pronated and have adequate padding at the elbows.
When not at the sides, the arms should be placed slightly lower than the shoulders. Keeping the arms abducted less than 90 degrees at the shoulders will help protect the brachial plexus. The elbows are bent so that the hands lie at the side of the head. Adequate padding of the elbows protects the ulnar nerve. The arms should be supported to prevent them from hanging too far below the patient's body. The upper portion of the arm should be free of pressure from the operating table and any positioning devices.
While in the prone position, the mattress can press against the abdomen, impeding both ventilation and venous return. Rolls or bolsters free the abdomen and relieve the increase in intraabdominal pressure. The rolls should extend from the iliac crest to the clavicle on both sides of the patient. After the rolls are placed, they shouldn't exert pressure on the upper arms.
Flexion of the knees reduces lumbosacral stretch and may prevent postoperative discomfort. The knees and ankles should be padded. In male patients, ensure that the testicles aren't compressed under the patient's body. In female patients, check to make sure pendulous breast tissue is not compressed or twisted under the body.
Once positioned for surgery, it's helpful to step back and visually inspect the patient before draping. This is the last chance to correct any mistakes made while placing the patient in the operative position. This is useful for any surgical position, not just when the prone position is employed.
A team effort
The surgical patient is under the effects of anesthesia and unable to protect himself from injury due to poor positioning. It's the responsibility of every member of the OR team to pay strict attention to the proper positioning of the patient. By adhering to sound principles of positioning, the OR nurse can spare the patient unnecessary pain and complications in the postoperative period. OR
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