There are two questions in case of acute bullet injuries: Is hot bullet sterile? and What are the indication for removal of bullet that has done no vital damage?
1. Hot bullet is sterile: This is found to be false by various articles [1,2,3,4]. Bullets can cause infection by two mechanisms; by carrying skin and associated flora with it [5] and by puncturing internal organs that have native bacterial flora like gut [6]. However this is not an indication of exploration and removal of bullet. Antibiotics have shown to effectively control this infection thus making the bullet an inert foreign body [exceptions noted below].
2. What are the indications of removal of bullet: In general, missiles retained in the soft tissues or muscles of the axial and appendicular skeleton become encased in a fibrous, avascular scar (7). As a result, they essentially become inert and are shielded from their host. It has been demonstrated that excellent long-term results can therefore be achieved without the routine removal of these missiles [10]. The risk of infection is low (2-3%), and the risk of dissolution of the bullet with local or systemic lead toxicity is extremely rare[7].
The risk of lead poisoning is seen in places where bullet is continuously bathed in fluid like in joints, near CSF or in a pseudo cyst [11-22]. Intraarticular bullet fragments cause synovitis as lead can be dissolved by synovial fluid [13] and can cause accelerated osteoarthritis [lead arthropathy] [16,17,18,22]. Rare complication like squamous cell carcinoma is reported around retained bullet [23]. A very interesting case report mentioned elevated serum lead levels during pregnancy in a woman with retained bullet in spine [what may be the cause of this accelerated lead dissolution during pregnancy?]. This caused elevated serum lead levels in the newborn and multiple congenital abnormalities [24,25 (incidentally these two reports are duplicate publication, where the same patient was published by the authors in two different journals and two years apart with significant changes in the authors list!]. Thus this may again be a relative indication of removal of bullet in a young female who wishes to conceive.
Thus generally retained bullet fragments are benign [7], and the surgeon should not try to remove them all. However, sometimes fragments maybe located in areas that will cause pain, such as around joints, or in the subcutaneous tissues. These fragments may be removed electively after the acute injury has healed [4]. Also from review of all articles [1-29] I could identify few indications for removal of Bullets
1. Bullet close to a joint
2. Bullets in hand or feet
3. When bullets can be felt below the skin (radiological assessment of depth is erroneous). Many a times, when treated conservatively the bullets will be pushed out towards the skin where they are palpable and then can be removed easily
4. Probably bullet lodged in intra discal area in spine
5. In spine if the bullet is responsible for secondary neurological problems or infection it should be removed [4]. Again bullet removal is debatable here in spine cases [9], however bullets in contact with CSF or spinal cord need to be removed [10]
6. Bullets lying close to major vessels may cause late aneurysms and may be an indication of removal once the acute injury has subsided [relative indication]
7. When bullet is located near nerve structures and there is irritation of the nerve with progressive neurologic signs or symptoms
8. Females who wish to conceive [24]
9. When easily accessible through the wound J
10. A relatively new reason for bullet removal is the clinical indication for a magnetic resonance imaging (MRI) study. This examination cannot be safely performed on patients with retained shrapnel because patients who undergo MRI examination may suffer from magnetic effects on the shrapnel (eg, pain, bruises, injury to nerves or blood vessels in the vicinity of the shrapnel). Thus, shrapnel removal is indicated before performing an MRI study [29].
Few more points that I came across during this review
1. Any joint that is affected in bullet injury has to be opened and thoroughly debrided and checked for bullet fragments
2. Bullet lodged in bone can be observed and do not require removal unless they are intraarticular or are lodged in the bone travelling through a joint causing a fistulous synovial tract between the joint and the bullet as reported by Worland [26 ]. This also alerts us to look at the tract through which bullet has travelled in the body and correlate.
3. Nonviable muscle, especially in an anaerobic environment, is ideal pabulum for the growth of many types of bacteria, especially clostridia. After a gunshot wound, the number of aerobes in devitalized muscle has been observed to be 10,000 organisms per gram of tissue at 6 hours and 100,000 at 12 to 24 hours, with the quantity of anaerobes at 6 hours falling within this range. Therefore, debridement optimally is done within 6 to 8 hours of injury. However, this timing is inexact because of the degree of tissue destruction, the presence of shock, and host resistance [27].
4. Wounds are not to be closed primarily [28]
3. Vascular embolisation of bullets is reported [and also migration into the portal system, pericardial space, spinal cord, kidneys, ureters, urethra, and lungs has been observed rarely [27].
I have tried to read as many full articles as possible to reach logical conclusions as above, however this should not be considered as a systematic review but as a general review on the topic
Regards
Ashok Shyam
Head of IORG
References:
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2. F.P. Thoresby, J.C. Watts. Gas gangrene of the high-velocity missile wound. Br J Surg, 54 (1) (1967), pp. 25–29
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