Thursday, February 4, 2010
Board Review: Retained Foreign Bodies
Originally Published: Modern Resident, October/November 2010
Original Article Author: Teresa M. Ross, MD
Georgetown-Washington Hospital Center
Submitted by: Rachel Engle, DO (Communications Committee Chair)
A case study: A 59 year old diabetic female was sent to the ED from her podiatrist's office over concern for a retained foreign body (FB) in her toe. Four days prior, she had impaled her right great toe on a blue wooden toothpick. She self-extracted a broken portion of the toothpick, but the toe had become progressively red and swollen, now with inclusion of the distal, dorsal portion of her foot. She complained of a painful FB sensation migrating towards the plantar aspect of the MTP joint of the great toe, worse with walking. She had no fever. At her podiatrist's office, a plain film of the foot was reportedly negative.
In the ED, the toe was obviously cellulitic. No FB was palpable on exam, but a punctuate hemorrhage on the toe seemed to indicate where the initial entry point had been. Bedside ultrasound localized a 1cm long FB penetrating the skin towards the MTP joint, 0.5cm below the skin at its closest point. However, after a successful nerve block, a 20 minute exploration failed to visualize the toothpick. The patient noted that she felt the toothpick had "moved even deeper" after all the probing on exam. The risk of deeper exploration towards the joint was deemed to outweigh the benefits of extraction, and the procedure was terminated.
The patient received a first course of IV Vancomycin. The toe was wrapped for delayed primary closure, and the patient was sent home on clindamycin, levofloxacin and oxycodone for pain. She was instructed to return for wound check and surgical referral in two days. The patient did not return to the ED for wound check, but did follow up in podiatry clinic, where they continued conservative management. Should we have tried harder to remove the foreign body?
Pearl: When to Try, When to Stop
What to Remove: Organic materials such as wood, thorns and cactus spines trigger the most severe inflammatory reactions with the greatest risk of infection. Ideally, these items should be removed promptly from soft tissue injuries. Suspect a retained FB in puncture wounds that develop infection or show poor response to antibiotics.
How to Image: This is difficult. Unlike metal, glass and gravel (which are often inert) organic materials are rarely visible on plain film and loose visibility on CT as well, as they absorb water with time and become increasingly isodense. Ultrasound by emergency physicians is highly operator dependent. In one study, EPs asked to detect a wooden FB in a cadaver showed sensitivity of 40-70% and specificity of 30-66% depending on the operator. Positive predictive value was 79.9% (95% CI 76.3%-83.5%), and negative predictive value was 20.0% (95% CI 16.2%-23.7%).
ED Extraction Techniques: Wound margins should be extended with a scalpel for better visibility. Blind probing by inserting and spreading a hemostat is acceptable for deep puncture wounds, but is especially dangerous in the hands, feet and face and is not recommended in the ED. Wooden fragments, in particular, can be impossible to locate precisely. The incision should be lengthwise with extraction via splinter forceps, or the incision can be made to remove a wedge of tissue where a superficial FB is expected to be. Subungual splinters must be removed, and partial or complete fingernail removal can facilitate this procedure.
Disposition: Importantly, the EM physician should recognize his or her limitations in foreign body removal, especially when the object is deep. He or she should devote 15-30 minutes to the procedure and then refer patients to surgery if more time is required. Patients should be informed prior to the procedure that exploration will be limited by time and equipment. Antibiotics are justified for wound infection or retained FB. If a FB is near a highly mobile joint, the area should be splinted for comfort and to prevent further injury. Delayed primary closure is appropriate for all infected wounds or those with poor blood supply. Patients should return for a wound check in two days if they have not yet seen their surgical consult.
1. Tintinalli, Emergency Medicine. 6th edition, 2004.
2. Crystal CS, et al. "Bedside Ultrasound for the Detection of Soft Tissue Foreign Bodies: A Cadaveric Study." J Emerg Med. 2009 May:36(4). 377-80