Anesth Analg 2009; 108:384-385
© 2009 International Anesthesia Research Society
doi: 10.1213/ane.0b013e31818e6944
LETTER TO THE EDITOR
Peripheral Neuropathy Following Colonoscopy Is Not Uncommon
Choon L. Bong, MBChB, FRCA, and
Christian Seefelder, MD
Department of Anesthesiology, Perioperative and Pain Medicine; Children's Hospital; Boston, Massachusetts; clbong1{at}gmail.com
To the Editor:
Colonoscopy is a common diagnostic procedure, which is usually performed under light sedation in adults. In children, this procedure often requires deep sedation or general anesthesia. Anesthesia risk for colonoscopy is generally considered low. In 2007, 746 colonoscopies were performed at our institution in patients aged 6 mo to 24 yr under general anesthesia or sedation provided by an anesthesiologist (typically propofol infusion). Three of these patients experienced postoperative neuropathies of their lower extremities. With Institutional Review Board approval, these cases were reviewed and are presented in Table 1. All three patients were thin and malnourished adolescents with a low body mass index, two had systemic inflammatory conditions and were receiving steroids. All patients were temporarily supine with the hips flexed and externally rotated and with the knees flexed and supported laterally ("frog leg position"), temporarily in a left lateral decubitus position, and the position was changed at least twice. The total procedure time and the time in the respective positions were all relatively long. While initially considered exceptional complications, our incidence of lower extremity nerve palsies after colonoscopy in 2007 (3 of 746 patients) is in fact similar to one reported in a prospective audit of children undergoing colonoscopy by Stringer et al.1 in 1999, where one patient out of 250 developed common peroneal nerve palsy.
The mechanisms of perioperative nerve injury are often obscure.2 Common causes include mechanical factors such as compression or stretch, or ischemia,3 and duration of trauma is important. Superficial nerves are particularly vulnerable, and paucity of subcutaneous fat in thin patients may be an additional risk factor. Other reported contributing factors include hypothermia, hypovolemia, dehydration, hypotension, hypoxia, and electrolyte disturbances.4 In our patients, direct pressure on the common peroneal nerve while in the lateral position and stretch of the sciatic nerve, as well as direct pressure on the peroneal nerve from lateral knee support in the "frog leg position" were the likely mechanisms of injury. Low body mass index, malnutrition, therapeutic use of steroids, long duration of the procedures and intraoperative position change were considered contributing risk factors for developing nerve injury following colonoscopy.
All three nerve injuries resolved, within days in one patient, 4 wk in the second, and more than 3 mo in the third. The last two patients had significant temporary disability, which required treatment with braces and physical therapy, resulting in additional inconvenience and expenses.
The occurrence and review of these neuropathies has resulted in increased awareness of the risk of neuropathy following colonoscopy at our institution. Attempts are made to use the "frog leg position" only briefly for insertion of the colonoscope and avoid it for prolonged duration. The superficial branch of the common peroneal nerve is padded while the patient is in the lateral position. Position changes during the procedure are minimized and performed with additional attention to avoiding pressure on or stretch of the nerves at risk.
REFERENCES
- Stringer MD, Pinfield A, Revell L, McClean P, Puntis JWL. A prospective audit of paediatric colonoscopy under general anaesthesia. Acta Paediatr 1999;88:199–202[Web of Science][Medline]
- Lui ACP, Thompson GE. Perioperative nerve injury. In: Benumof JL, Saidman LJ, eds. Anesthesia and perioperative complications. St. Louis: Mosby, 1999;192–205
- Dawson DM, Krarup C. Perioperative nerve lesions. Arch Neurol 1989;46: 1355–60[Abstract/Free Full Text]
- Sawyer RJ, Richmond MN, Hickey JD, Jarratt JA. Peripheral nerve injuries associated with anaesthesia. Anaesthesia 2000;55:980–91[Web of Science][Medline]
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