Microsurgery: Transplantation and Replantation by Harry J. Buncke, MD, et al.
  Table of Contents / Chapter 39:
Anesthesia for Microsurgery
  Lateral Decubitus Position. This position, which is used for harvesting of latissimus dorsi and serratus anterior muscle flaps, presents a number of potential problems. After induction of anesthesia, intubation, and placement of necessary monitors, the patient is turned into the lateral decubitus position and stabilized with the aid of a vacuum bean bag. A soft towel roll is placed in the dependent axilla to prevent neurovascular compression. The head must be well supported so that the cervical spine is maintained in a neutral position. A foam pad under the dependent cheek will prevent undue pressure on the malar eminence. The eyes should be taped shut. The dependent arm is usually in a partially extended position with appropriate padding of the hand and elbow. To facilitate the surgical exposure during muscle harvesting, the arm of the operative side is maximally abducted during most of the period of dissection. Prolonged abduction has resulted in brachial plexus stretch injuries, so it is important that all members of the team be aware of this possible injury and abduct the arm for as short a period as possible. It is useful to change the arm position at frequent intervals. As soon as the harvesting is complete and the wound closed, the arm should be adducted. If brachial plexus stretch injury occurs, the patient will complain postoperatively of numbness over most of the arm and muscle weakness ranging from mild to profound. Almost always, the sensation returns in 3 to 5 days and muscle strength over a slightly longer period. A pillow is placed between the knees to help provide stability and alleviate pressure in areas of contact. At times, it is difficult to keep the patient in the lateral position, and gradual changes in position may cause unexpected pressure points. These position changes may not be noticed when most of the patient, including the head, is covered by surgical drapes. The anesthesiologist, who frequently checks the position of the head, shoulders, and arms, will be aware of position changes and will correct the position before pressure problems can occur.  

Prone Position. This position, although not frequently used, may be necessary in the surgical treatment of decubitus ulcers. The positioning of the head may be difficult, especially in a quadriplegic patient who has had a cervical spine fusion. Care must be taken to avoid pressure on the eyes. The head can be supported by a multiposition neurosurgical headrest with the forehead resting on a thick rubber padding, or if this is not available, foam pads can be used under the forehead for support. If possible, the arms should be adducted along the sides with pads surrounding the elbows. If the arms need to be abducted, the precautions mentioned above must be taken. Rolls placed under the iliac spine help prevent excess pressure over the vena cava. These rolls, however, may compress the lateral femoral cutaneous nerve, causing meralgia paresthetica. Foam rubber padding over the rolls may help prevent this problem.

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