SOFT TISSUE FOREIGN BODIES

Only a small percentage of wounds contain a foreign body.

Most but not all foreign bodies may be discovered with thorough wound examination.

PATHOPHYSIOLOGY

Retained foreign bodies may lead to a severe local inflammatory response (eg, wood, thorns, spines), chronic local pain (eg, glass, metal, plastic), local toxic reactions (eg, sea urchin spines, catfish spines), systemic toxicity (eg, lead), or infection.

Infection is the most common complication of a retained foreign body and typically the infection is resistant to antibiotic therapy.

CLINICAL FEATURES

The mechanism of injury, composition and shape of the wounding object, and the shape and location of the resulting wound may increase the risk of a foreign body.

Lacerating objects that splinter, shatter, or break increase the risk of a foreign body.

Discoloration of the skin, palpable mass, sharp well-localized pain with palpation, and limitation of joint movement should heighten suspicion for a foreign body.

In adults, the perception of a foreign body more than doubles the likelihood of one being present.

Although all puncture wounds and apparently superficial wounds can hold foreign bodies, wounds deeper than 5 mm and those whose depths cannot be investigated have a higher association with foreign bodies.

Patients returning to the ED with retained foreign bodies may complain of sharp pain at the wound site with movement, a chronically irritated non-healing wound, or a chronically infected wound.

DIAGNOSIS AND DIFFERENTIAL

Imaging studies should be ordered if a foreign body is suspected.

No single imaging modality is ideal for all types of foreign bodies.

Most foreign bodies (80–90%) can be seen on plain radiographs. Metal, bone, teeth, pencil graphite, glass, gravel, sand, aluminum, and a few types of plastic are visible on plain film while most plastics and organic material specifically wood, thorns, cactus spines, and some fish bones cannot be seen on plain film.

CT scan is much more sensitive than plain film in detecting foreign bodies.

Ultrasound is probably less accurate than CT, but it reportedly has a >90% sensitivity for detecting foreign bodies larger than 4 to 5 mm in size.

MRI can detect radiolucent foreign bodies and is more accurate in identifying wood, plastic, spines, and thorns than the other modalities.

Fluoroscopy can be useful to detect metal, gravel, glass, and pencil graphite in real time.

EMERGENCY DEPARTMENT CARE AND DISPOSITION

Careful exploration of the depths of all wounds increases the likelihood of finding a foreign body. Extending the edges of the wound is often necessary to thoroughly investigate for foreign bodies.

Blind probing with a hemostat is less effective, but may be utilized if the wound is narrow and deep, and extending the wound is not desirable.

Not all foreign bodies need to be removed. Indications for foreign body removal include potential for infection, toxicity, functional problems, or potential for persistent pain.

Vegetative material and heavily contaminated objects should always be removed.

Radiopaque foreign bodies may be localized using skin markers and x-ray or fluoroscopy. Hypodermic needles may be inserted at 90° to each other near the foreign body to help with localization. Alternatively bedside ultrasonograpy may be used.

Most busy emergency physicians will only be able to dedicate 15 to 30 minutes to removal procedures.

Needles may be difficult to locate. If the needle is superficial and can be palpated, an incision can be made over one end and the needle removed. If the needle is deeper, then an incision can be made at the midpoint of the needle and the needle grasped with a hemostat and pushed back out through the entrance wound. If the needle is perpendicular to the skin, the entrance wound should be extended. Then pressure applied on the wound edges may reveal the needle so that it can be grasped and removed.

Wooden splinters and organic spines are difficult to remove because of their tendency to break.

Only splinters that are superficial should be removed by longitudinal traction. Otherwise the wound should be enlarged and the splinter lifted out of the wound intact. If the splinter is small and localization is difficult, then a block of tissue may be removed in an elliptical fashion and the remaining wound closed primarily. Since infection occurs frequently, subungual splinters should be removed with splinter forceps or by excising a portion of nail over the splinter and then removing the splinter intact.

Cactus spines may be removed individually or with an adhesive such as facial gel, rubber cement, or household glue.

Several techniques have been established to remove fishhooks, including the string-pull method, the needle-cover technique, or the advance-and-cut technique. Alternatively, the wound may be enlarged down to the barb and the fishhook removed. When using any of these techniques, anesthesia should be injected around the fishhook entry site.

After removal of a foreign body, the wound should be adequately cleaned and irrigated.

If multiple foreign bodies were removed, a post procedure x-ray should be obtained.

If the potential for infection is low and all foreign bodies were removed, the wound may be closed primarily.

If there is a significant risk for infection, delayed primary closure is preferred.

If a foreign body is suspected or identified radiographically but cannot be located even after thorough wound evaluation, or if the foreign body is located in an area that prohibits removal, then the patient should be informed and referred to a surgical specialist for delayed removal. If the foreign body is near a tendon or joint, the limb should be splinted. Prophylactic antibiotics are widely prescribed, but their efficacy has not been determined.