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A ballistics expert examines the effects of bullets on tissues. He defines a "penetrating missile" as one that delivers an entrance wound but no exit wound, and a "perforating missile" as one that possesses both entrance and exit wounds. He also defines bullet "yaw" as the tumble of a bullet or its tendency to turn sideways in flight. A diagram of bullet yaw is seen in Figure A. Which of the following scenarios leads to the greatest transfer of kinetic energy to tissues?
Penetrating missile with mass "2m", velocity "v", yaw of 90 degrees at the point of impact
Perforating missile with mass "m", velocity "2v", yaw of 0 degrees at the point of impact
Penetrating missile with mass "m", velocity "2v", yaw of 90 degrees at the point of impact
Perforating missile with mass "m", velocity "2v", yaw of 90 degrees at the point of impact
Penetrating missile with mass "2m", velocity "v", yaw of 0 degrees at the point of impact
Select Answer to see Preferred Response
A penetrating (but not perforating) missile with highest velocity (2v) and largest yaw (90 degrees, or sideways travel) leads to greatest transfer of kinetic energy.
The kinetic energy (E) of a bullet is proportional to its mass (m), and velocity (v) squared. A bullet of mass m traveling at 2v will have greater E than one of mass 2m traveling at v. Maximum energy transfer is achieved with yaw of 90 degrees (sideways). Yaw is decreased with longer distances of bullet travel, allowing a bullet to strike its target nose-on. Penetrating (non-exiting) missiles deliver all their contained kinetic energy, while perforating (exiting) missiles transfer significantly less energy to tissues
Bartlett et al. reviewed ballistics and gunshot injuries. They state that energy transfer depends on 6 factors including: (1) amount of kinetic energy at impact, (2) stability and entrance profile (yaw), (3) caliber, construction and configuration of the bullet, (4) distance and path traveled within the body (penetrating vs perforating), (5) biological characteristics of tissues impacted, and (6) mechanism of tissue disruption (stretching, tearing, crushing).
Figure A illustrates the concept of bullet yaw. Illustration A shows blocks of gelatin perforated by similar caliber missiles at different velocities (A, 1,000fps; B, 2,800 fps), with arrows indicating missile tracks.
Answers 1, 2, 4, 5: These scenarios do not lead to the greatest transfer of kinetic energy to tissues.
Bartlett CS, Helfet DL, Hausman MR, Strauss E.
J Am Acad Orthop Surg. 2000 Jan-Feb;8(1):21-36. PMID: 10666650 (Link to Abstract)
Bartlett, JAAOS 2000
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Average 2.0 of 43 Ratings
A 24-year-old male presents after being shot in the lower back. Radiographs and advanced imaging show that the bullet traversed the paraspinal musculature, entered the pelvis below the pelvic brim, and is currently lodged in the ilium. No intra-articular involvement was noted, and the bony injury is stable. No occult blood is noted on the rectal examination. The police report indicates that the bullet was fired from a low-velocity weapon. Which of the following is the most important treatment for this patient assuming he is hemodynamically stable?
Immediate exploratory laparotomy and bullet removal
Bullet removal followed by surgical stabilization of the ilium
Immediate surgical debridement of the bullet tract and delayed closure of the soft tissue wound
Empiric antibiotic therapy and observation
Based on the clinical presentation, this patient should be treated initially with empiric antibiotic therapy and observation.
The available literature shows that transabdominal GSW with intra-articular contamination should be urgently débrided and irrigated; extra-articular transabdominal GSW with stable fracture patterns may be managed with observation and empiric antibiotics. Bullets lodged in intra-articular locations should be removed, but retained bullets in other anatomic locations do not necessarily warrant removal.
Watters et al. retrospectively collected Information regarding surgical débridement of pelvis low velocity gunshot wounds, retained foreign bodies, and/or concomitant gastrointestinal (GI) injury was analyzed for relationships of such events to infection rate in 56 patients. The authors found that there was no increased incidence of infection in the absence of aggressive surgical débridement of pelvis gunshot wounds. The study also demonstrated that retained bullets and bullet fragments did not increase the risk of infection, even after penetrating the GI tract organs.
Zura et al. completed a review article on the treatment of gunshot wounds to the hip and pelvis. The authors state that antibiotic treatment usually is indicated for patients with gunshot wounds to the pelvis, but is controversial in patients with low-energy wounds. Furthermore they state that fractures are treated based on their stability and wound care should be determined by the personality of the injury, and not solely based on the velocity of the missile.
Miller et al. completed a recent review article on transabdominal gunshot wounds to the hip and pelvis. They state that extra-articular transabdominal GSW with stable fracture patterns may be managed with observation and empiric antibiotics.
Answer 1: Immediate exploratory laparotomy would be indicated in the setting of persistent hemodynamic instability or positive peritoneal signs.
Answer 2: There is no evidence that bullet removal is necessary when it is in an extra-articular location. Furthermore the bony injury is stable, and does not warrant fixation.
Answer 3: Immediate surgical debridement is not necessary without intra-articular involvement or severe soft tissue injury.
Answer 5: Sigmoidoscopy would be necessary if occult blood was noted on rectal examination.
Watters J, Anglen JO, Mullis BH
J Orthop Trauma. 2011 Mar;25(3):150-5. PMID: 21278605 (Link to Abstract)
Watters, JOT 2011
Zura RD, Bosse MJ
Clin. Orthop. Relat. Res.. 2003 Mar;(408):110-4. PMID: 12616046 (Link to Abstract)
Zura, CORR 2003
Miller AN, Carroll EA, Pilson HT.
J Am Acad Orthop Surg. 2013 May;21(5):286-92. PMID: 23637147 (Link to Abstract)
Miller, JAAOS 2013
Average 3.0 of 22 Ratings
A 21-year-old male presents to the emergency department after sustaining a gun shot wound to his abdomen. Subsequent radiographs reveal a bullet in the L2 vertebral body. Physical exam shows no neurologic deficits. He undergoes emergent laparotomy and is found to have a small bowel laceration. What would be the preferred treatment following his exploratory laparotomy and small bowel repair?
Intravenous antibiotic coverage for Gram negative bacteria for 7 days
Surgical decompression and bullet fragment removal
Broad-spectrum oral antibiotic coverage for 7 days
Broad-spectrum intravenous antibiotic coverage for 7 days
The clinical presentation is consistent with a GSW with bowel perforation and a retained bullet in the vertebral body. Because the patient is neurologically intact broad-spectrum intravenous antibiotic coverage for 7 days is the most appropriate treatment.
Gunshot wounds to the spine present relatively little risk of infection in most cases. When there has been an injury to the small bowel, the risk of infection can be minimized with a 7-day course of broad-spectrum antibiotics. Indications for surgery include when a neurological deficit is present that correlates with imaging findings of neurological compression by the missile, or when the missile is in contact with the CSF posing a risk for metal toxicity.
Roffi et al performed a Level 4 study of 42 patients that sustained a gunshot wound that perforated the stomach or bowel and then entered the spinal column. They found that an extended regimen of broad spectrum antibiotics combined with bedrest appeared to significantly reduce the risk of spinal or paraspinal infection, whereas early bullet removal did not significantly prevent the occurrence of infection.
Velmahoos et al performed a Level 4 study including 24 patients that sustained a gunshot wound to the spine with associated colonic injury. They found that the incidence of sepsis was 8.4% (compared to 5% in non-bowel injuries) and concluded that retainment of the bullet did not increase the rate of sepsis.
Answer 1: The patient needs coverage for both Gram+ and Gram- organisms.
Answer 2: There are no indications for surgery at this point.
Answer 3: Antibiotics are indicated to decrease the risk of infection.
Answer 4: Intravenous antibiotic has been found to be more effective than oral antiobiotics.
Roffi RP, Waters RL, Adkins RH.
Spine (Phila Pa 1976). 1989 Aug;14(8):808-11. PMID: 2781395 (Link to Abstract)
Roffi, SPINE 1989
Velmahos G, Demetriades D.
Ann R Coll Surg Engl. 1994 Mar;76(2):85-7. PMID: 8154819 (Link to Abstract)
Average 4.0 of 20 Ratings
What is the most appropriate treatment for a 17-year-old boy who sustained a gunshot wound to his forearm from a handgun with a muzzle-velocity of 1000 feet/second if he is neurovascularly intact and radiographs reveal no fracture?
Irrigation and local wound care in the emergency department
Emergent irrigation and debridement in the operating room with vacuum-assisted wound closure
Emergent irrigation and debridement in the operating room with 7 days of intravenous antibiotics
Wound closure in the emergency department with follow-up wound check in 1 week
Exploration and removal of all bullet fragments in the emergency department and 10 day course of oral antibiotics
The question refers to appropriate management of a gunshot wound to the forearm. The first question that must be answered when evaluating gunshot injuries is whether the gunshot is low velocity or high velocity. Low-velocity wounds are less severe, are more common in the civilian population, and are typically attributed to bullets with muzzle velocities below 1,000 to 2,000 feet per second. Tissue damage is usually more substantial with higher-velocity (greater than 2,000 to 3,000 fps) military and hunting weapons. In this question, a muzzle velocity of 1,000 ft/sec is provided. Low velocity injuries with stable, non-operative fractures can be treated with local wound care.
The two referenced articles offer guidance for treating low-velocity gunshot injuries with stable, non-operative fracture patterns. The first article by Geissler et al is a retrospective study comparing 25 patients that prospectively received local irrigation and debridement, tetanus prophylaxis and a long acting cephalosporin intramuscularly to a random retrospective sample of 25 patients with similar ballistic-induced fractures and wounds managed by local debridement and 48h of intravenous antibiotics. One infection occurred in each group, requiring further therapy. It was concluded that patients with low-velocity gunshot induced fractures can be managed without the use of short-term intravenous antibiotics with no increased risk of infection.
In the second study, Dickey et al evaluated the efficacy of an outpatient management protocol for patients with a gunshot-induced fracture with a stable, non-operative configuration. 41 patients with a grade I or II open, non-operative fracture secondary to a low-velocity bullet were treated with 1gm of cefazolin administered in the emergency room and a 7-day course of oral cephalexin. No patient developed a deep infection. Thus, local I&D, tetanus, and oral antibiotics for 2-3 days is adequate for low velocity gunshot wounds.
Geissler WB, Teasedall RD, Tomasin JD, Hughes JL.
J Orthop Trauma. 1990;4(1):39-41. PMID: 2313428 (Link to Abstract)
Geissler, JOT 1990
Dickey RL, Barnes BC, Kearns RJ, Tullos HS.
J Orthop Trauma. 1989;3(1):6-10. PMID: 2709206 (Link to Abstract)
Dickey, JOT 1989
Average 2.0 of 34 Ratings
A 24-year-old man who sustained a gunshot wound to the abdomen ten hours earlier was brought to the emergency department. On physical examination he was found to have 4 of 5 weakness in his bilateral lower extremities. Radiographs are shown in Figure A. Computed tomography of the lumbar spine showed retained missile in the vertebral body and paraspinal soft tissues, but not within the spinal canal. His FAST was positive and he underwent an emergent exploratory laparotomy where an injury to the cecum was identified and treated. Management should now include which of the following?
Bullet fragment removal from a transabdominal approach
Bullet fragment removal from a retroperitoneal approach
Broad-spectrum oral antibiotics for 3-5 days
Broad-spectrum intravenous antibiotics for 7-14 days
IV methylprednisolone at 5.4mg/kg/h for 48 hours
The patient in the scenario has a GSW to the lumbar spine with neurologic deficits but without a retained missile in the spinal canal. In patients with visceral injury, the treatment is broad-spectrum antibiotic coverage for 7 days.
Kumar et al reviewed 33 patients with GSW to the spine and associated visceral injuries. They concluded that 7 days of antibiotic treatment targeted at colonic flora is the treatment of choice.
Roffi et al reviewed 51 low-velocity GSW that perforated the viscus prior to the spine. They concluded that broad spectrum antibiotics combined with bedrest significantly reduced the risk of spinal or paraspinal infections. Furthermore, bullet removal had no effect on infection rates.
Velmahos et al followed 153 GSW to the spine for 28 months. While rates of sepsis were higher in the lumbar spine than cervical and thoracic spine, they concluded that retained bullets do not increase the likelihood of septic complications.
Answer 1 & 2: Indications for surgery with a GSW to the lumbar spine include 1) spinal instability 2) a neurologic deficit is present that correlates with radiographic findings of neurologic compression by the missile. 3) Lead missile is in contact with the cerebrospinal fluid (CSF). This patient does not have any of these criteria.
Answer 5: GSWs are a contraindication for spinal dose steroids.
Kumar A, Wood GW 2nd, Whittle AP.
J Orthop Trauma. 1998 Sep-Oct;12(7):514-7. PMID: 9781777 (Link to Abstract)
Kumar, JOT 1998
Average 3.0 of 34 Ratings
HPI - GSW since 2nd of July, through the left inguinal region, there injury to the bowl, colostomy was done, X-ray reveal fracture to both ischial rami, and right proximal femur
What are the possible fixation options?
HPI - Multiple gun shot of humerus and forearm on 2/ february.no vascular or neurological defect.wound 4x4cms on lt humerus.and 6x4cms on distal dorsum of lt forearm.POP SLAPfor lt humerus.2: POP SLAP FORLT FOREARM.
How will you treat the case.?
HPI - high velocity gun shot wound, inlet on the left hip above greater trochanter, presented with right hip pain.
what is the appropriate treatment?
HPI - Accidental shotgun injury to right lower leg
HPI - close range (1foot) shotgun injury. bad soft tissues. managed in spanning exfix. delayed orif prox tibia and distal femur. progressive stiffness and failure of fixation. presents to me a year down the line. no obvious signs of infection. tissues good. ffd of 50degrees ( slight jog of motion) and still very sore.
pt young and motivated.
what options does he have
HPI - Patient was shot at left arm. Treated in another hospital where received antibiotics and wound irrigation and closure but no fixation. Transferred to our unit 10 days after shot.
How would you treat this patient?
HPI - Patient was shot on left buttock. Presented walking w/o neurovascular deficits
What approach would you use for the bullet removal?
HPI - Patient was shot on the right hip 1 year ago. Was hospitalized but never operated and went asymptomatic a few weeks after injury until months ago, when started to loose weight had progressive right hip pain. Clinical analysis show plumb intoxication.
What would be your treatment of choice at presentation before surgery?