To the Editor:--The article by Warner et al. concerning postoperative ulnar neuropathy may have provided sufficient information and methodology to illuminate primary causative mechanisms. [1]The correlation to onset occurring postoperatively and in association with prolonged hospitalization demands that the cause also must be sought outside the operating room. Although injury can be caused by improper intraoperative positioning, this usually is recognized, and preventive measured are implemented. Stoelting conjectures that "unavoidable events associated with anesthesia and surgery" might cause injury. [2]Prolonged recuperation after major surgery can occur and is associated with significant changes in personal habits and levels of consciousness.
Case Report.
I (age 37-39 yr, ASA physical status 1, 85 kg) underwent two major laparotomies via xiphoid-suprapubic midline incision with hospitalization of 1 week each time. Customarily, I sleep prone. Postoperatively, I found that I slept exclusively supine with my hands positioned across my lap, causing me to wake frequently with numbness and paresthesia of the fourth and fifth digits, at times bilaterally. Arousal and active motion of the hands resolved this transient problem without permanent lesions. After the third postoperative day, the skin over both olecranons was chaffed and painful (because of supine movement using the elbows), and I noticed the symptoms occurring during the day, generally while sitting in an armchair, as I was positioning my elbows on the medial epicondule to avoid pain from the raw skin over the oleranons. I began to sleep laterally for the same reason. At home, I ingested 0.25 mg triazolam HS (instead of 25 mg diphenhydramine used in the hospital) and awoke the next day with deep pain over the left greater trochantor, as if I had bruised my hip during sleep. The next night, after the same dose of triazolam, the same pain over my right hip developed. I attribute the pain to deep pressure scores secondary to benzodiazepine central nervous system depression. Since the surgery, I cannot sleep prone and, frequently, am awakened supine with ulnar paresthesias, even while sleeping on the padded "egg crate" mattress. provided while I was "on call" in the hospital.
Discussion.
Intraoperative ulnar nerve protection routinely is discontinued with placement of the patient onto the gurney and throughout subsequent convalescence. The search for causative mechanisms of ulnar neuropathy during this period in previous studies has not occurred. [1,3-5]Prolonged supine positioning alone may result in cumulative and definitive injury, because personal habits including elbow-leaning have been proposed as causative mechanisms. [6]Clearly, my convalescence was associated with significant elbow-leaning.
Our inability to understand this process to date may be a result of examining the problem only as an anesthetic complication. Contemporary ulnar neuropathy may occur because of absent concerns for postoperative protection, compounded by frequent administration of sedatives, analgesics, or neuromuscular blocking agents. I hope Warner et al. will reexamine the available data in this new light, given their unique database.
Paul Martin Kempen, M.D., Ph.D.; Associate Professor; Co-Director of Obstetric Anesthesia; Department of Anesthesiology; Louisiana State University Medical Center; P.O. Box 33932; Shreveport, Louisiana 71130-3932.
(Accepted for publication March 21, 1995.)
