Isolated lower lip edema: A rare complication of prone positioning.

Sir,

Numerous complications have been reported with the prone position, including injuries to eyes, peripheral nerves, pressure points, and swelling of the tongue, parotid and submandibular gland.[1] We report a case of isolated lower lip edema following spine surgery in the prone position.

A 35-year-old healthy woman was posted for L5-S1 posterior lumbar interbody fusion. Her preoperative assessment and investigations were normal.

After intubation, the endotracheal tube was taped onto the right side of the mouth. A Philips adult reusable oropharyngeal temperature probe with module number 21075A compatible with the Philips IntelliVue MP 30 (M8002A) monitor was inserted adjacent to the tracheal tube. For prone positioning, a foam head rest with T-shaped cut outs for the eyes, nose, mouth, and endotracheal tube was used. It was covered with plastic to prevent soiling with secretions.

The head was maintained in neutral position and arms placed by the side of the head on arm boards. It was ensured there was no pressure on the eyes, nose, mouth and the endotracheal tube was not kinked. Pillows placed horizontally under the thorax and pelvis ensured a free abdomen.

The surgery lasted 9 h with approximately 500 mL blood loss for which 3 L of crystalloid and 1 L of colloid (volulyte) was administered. The patient had stable intraoperative hemodynamics and adequate urine output.

After surgery when the patient was turned supine, we noticed that the patient's lower lip was swollen [Figure 1]. The center of this lip, mucosa near the lower incisors and the skin over the chin were erythematous [Figure 2]. The upper lip was normal. There was no macroglossia, conjunctival or periorbital edema. The endotracheal tube was in place, but the temperature probe had dislodged. The patient was extubated fully awake and breathing adequately.

Figure 1

Isolated lower lip edema

Figure 2

Erythematous mucosa near lower incisors

After dermatology consultation, she was started on a dehydrating agent (magnesium sulfate), glycerin gel and topical steroids. The swelling resolved gradually, and the patient was discharged from hospital.

Edema of the face, neck, and tongue has been reported following prolonged neurosurgical procedures. Excessive flexion of the neck causes kinking and obstruction of internal jugular vein in the neck, leading to obstructed venous drainage from lingual, pharyngeal, and facial veins.[2]

If there were excessive flexion of the head, there would have been edema of face and tongue. Fluid overload would have caused conjunctival edema. A case has been reported of allergic contact dermatitis to the foam where the patient developed erythematous rashes and edema over his face and neck.[3] Our patient had no direct contact with the foam since it was covered with plastic, and edema and erythema were limited to the lower lip and chin.

A probable cause could be the lower lip being caught between the teeth, causing the erythema and swelling of the lip. An oral airway was not used as case reports have attributed them to causing trauma to lips, macroglossia, uvular edema and sore throat, especially when used for lengthy surgeries.[24] We could have used a proper sized soft airway or bite block made of gauze rolls. These are soft enough to prevent dental trauma, but firm enough to stabilize the tracheal tube and prevent biting of the lip or tube during lighter planes of anesthesia. Another probable cause could be displacement of the temperature probe to the center of the mouth causing pressure injury to the lip and chin. Alsiddiky reported a similar case of lip necrosis caused by direct pressure from the endotracheal tube being pushed against the lip by the gel pad used to support the face during prone positioning.[5]

Improper positioning can lead to untoward complications. Meticulous attention to detail while positioning and regular intraoperative checks can prevent most of them.

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Conflicts of interest

There are no conflicts of interest.