One bullet, five compartments: a transregional gunshot trajectory and the limits of operative intervention

Abstract

Gunshot wounds with transregional bullet trajectories present significant diagnostic and management challenges. We report the case of an 20-year-old male who sustained a single gunshot wound entering at the left angle of the mandible, traversing the neck with injury to the thyroid cartilage, ricocheting off the right sternoclavicular joint and tracking through the right lung causing haemopneumothorax, before lodging in the perinephric fat adjacent to the right kidney. Pan-scan computed tomography (CT) was pivotal in delineating this complex trajectory. Management required a multidisciplinary approach involving Head & Neck surgery, Trauma surgery, Cardiothoracics, and Intensive Care. Diagnostic laparoscopy confirmed no peritoneal breach, supporting selective non-operative management (SNOM) of the retroperitoneal bullet. This case highlights the importance of thorough CT imaging from head to pelvis, the safety of SNOM for retroperitoneal bullets in stable patients, and the necessity of coordinated multidisciplinary surgical care for managing complex transregional gunshot injuries.

Introduction

Penetrating ballistic trauma is a major cause of morbidity and mortality globally, attributable to 251 000 deaths each year [1]. In Australia, the incidence of firearm fatalities is rare at 0.9 deaths per 100 000 people, and this has been steadily declining over the past 40 years [2]. Penetrating injuries account for just 3.7% of major trauma presentations in Australia [3], and firearm assault is uncommon, making up 0.2% presentations to tertiary trauma centres within New South Wales [4]. Management of these injuries is approached in a systematic and protocolized manner.

Ballistic injuries can have unpredictable, non-linear trajectories and bullets can rotate, be deflected by bony structures, or traverse anatomical regions far removed from the entry wound [5]. These transregional trajectories pose a diagnostic challenge as clinical assessment alone guided by the visible entry wound may dramatically underestimate the extent of internal injury.

Penetrating neck injury (PNI) resulting in insult to the vascular or aerodigestive tract can lack correlation between the zone of the external wound and that of the internal injury [6]. This can make assessment of injury challenging, and computed tomography (CT) imaging and open neck exploration may be required. Penetrating abdominal injuries are associated with high rates of intra-abdominal injury and often necessitate exploratory laparotomy. Laparotomy for abdominal gunshot wounds is associated with high rates of complications and negative laparotomy [7]. Selective non-operative management (SNOM) may be suitable for patients with abdominal gunshot wounds who are haemodynamically stable, without intra-peritoneal injury [7].

In our case, the bullet entered at the left angle of the mandible, lodging in the perinephric fat adjacent to the right kidney, after traversing the neck, right sternoclavicular joint, and passing through the right thorax. This case highlights the management of PNI, the value of diagnostic laparoscopy in abdominal gunshot wounds, and the use of SNOM in stable patients, and the necessity of coordinated multidisciplinary care.

Case report

An 20-year-old male presented to a peripheral Emergency Department with dyspnoea and an expanding cervical haematoma following a suspected gunshot wound. He was haemodynamically unstable, recording a blood pressure (BP) of 85/50, heart rate (HR) 110, and SpO₂ 95%. Initial chest X-ray demonstrated a right haemopneumothorax and extensive subcutaneous emphysema of the neck and chest. The patient was promptly intubated for airway protection and transferred to a tertiary hospital with a major trauma service.

Upon arrival, his observations were BP 137/66, HR 108, respiratory rate 20, and SpO₂ 97%. The primary survey identified a 1 cm penetrating wound situated at the left angle of the mandible, on the border of zones II and III of the neck, with no hard signs of PNI (Figs 1 and 2). A right intercostal catheter (ICC) was inserted, draining 250 ml of frank blood. Following ICC insertion, the patient experienced transient hypotension with sBP dropping to 70 mmHg and spontaneously improving to 100/59. One unit of packed red blood cells was given and his haemoglobin (Hb) remained stable in the 130 s range.

Whole-body CT and angiogram of the neck demonstrated a sternocleidomastoid (SCM) haematoma with extensive gas locules in the neck consistent with PNI, injury to the thyroid cartilage with subcutaneous emphysema around the laryngeal cartilages, injury to the right sternoclavicular joint, a right haemopneumothorax, and a bullet lodged in the right perinephric fat with no evidence of intraperitoneal injury (Fig. 3). A small amount of free gas was noted adjacent to the liver but it was difficult to determine if this was within the peritoneal cavity or chest wall.

The patient was admitted to the Intensive Care Unit (ICU). The following morning, the Trauma service performed a diagnostic laparoscopy which revealed no peritoneal breach, diaphragmatic injury, or intraperitoneal free fluid or blood, confirming an entirely retroperitoneal bullet trajectory. Given these factors and ongoing haemodynamic stability, a SNOM approach was taken for the retroperitoneal bullet.

Given the mechanism of injury and the necessity to definitively evaluate the aerodigestive tract, the Head & Neck and Ear, Nose, and Throat (ENT) subsequently performed a direct laryngoscopy and formal neck exploration. Direct laryngoscopy confirmed no obvious airway mucosal defect. Surgical exploration traced the bullet’s entry wound at the left angle of the mandible to a 1.5 cm defect associated with severely comminuted thyroid cartilage. The wound tract extended through the right SCM, causing an intramuscular haematoma but notably spared the carotid sheath. Active bleeding from the right clavicular head was successfully controlled with bone wax. The tract was noted to angulate infero-posteriorly into the thoracic cavity. The defect in the thyroid cartilage was formally repaired using a sternohyoid muscle flap, and a surgical tracheostomy was performed to secure the airway.

The patient remained intubated and sedated in ICU secondary to agitation on weaning sedation. On post-operative day 3, he became febrile. A subsequent septic screen yielded negative results; however, empiric piperacillin-tazobactam was initiated in the context of a high sputum burden. On day 5, a gastroscopy performed by the Trauma service demonstrated a normal oesophagus and gastric mucosa. The ICC was removed on day 7, followed by successful tracheostomy decannulation on day 8. By post-operative day 9, the patient was transitioned from ICU to the trauma ward where a formal swallow assessment by Speech Pathology was passed, allowing for progression to a normal diet. The patient remained clinically stable and was safely discharged home on day 11.

Discussion

Complex laryngotracheal trauma requires rapid diagnosis and management with the primary aim of first stabilizing the airway followed by repair of injuries [8]. Diagnosis relies on direct visualization of the laryngeal mucosa via flexible laryngoscopy, while CT may be performed in stable patients to identify fractures of laryngeal bone and cartilage and associated injuries [9]. A CT angiogram should be performed if vascular injury is suspected, with the carotid artery being the most common vascular structure injured [8].

The Schaefer-Fuhrman classification system helps guide management based on the severity of injury [10, 11]. Low-grade injuries, group 1 and 2, can typically be managed with close observation and non-operative interventions [12]. Higher grade injuries, group 3 and above, involve displaced cartilage fractures, mucosal tears exposing cartilage, or instability of the larynx, and require an open neck exploration, precise anatomical reduction and fixation, or targeted stenting, or regional muscle flap repair as necessary [12]. Gunshot wounds can result in complex comminuted cartilage fractures which are difficult to reduce. Myoplasty can be considered in these cases to secure an airtight seal and provide a blood supply necessary to promote local healing [13]. In our patient. the anterior aspect of the thyroid cartilage was shattered at the laryngeal prominence with an associated 1.5 cm defect just superior to the level of the vocal cords. A sternohyoid flap was secured over this defect.

The initial management of multi-compartment penetrating trauma requires a systematic approach to secure the airway and deal with major threats to life affecting breathing and circulation. Primary survey and Focused Assessment of Sonography in Trauma (FAST) scan enable a rapid assessment of injuries. Attention should be made to entry and exit points of penetrating injuries to help determine wound trajectories and potential injuries to organs. Patients with abdominal injuries that penetrate the peritoneum of with haemodynamic instability require urgent exploratory laparotomy, while CT is indicated in stable patients to further assess for injury [14].

Retroperitoneal penetrating trauma carries a high risk of missed injuries. The most commonly injured organs are the colon, spleen, and kidney [15]. Gunshot wounds cause greater injuries due to their high kinetic energy, and trajectories can be unpredictable [13]. In haemodynamically stable patients where the trajectory of the gunshot wound is uncertain, diagnostic laparoscopy is indicated to assess for diaphragmatic injury and peritoneal breach, and can avoid proceeding with an unnecessary laparotomy, where these are absent [15, 16]. Where the peritoneum is penetrated, the risk of intra-abdominal injury can be as high as 98% [14]. In a retrospective review of 318 patients over 15 years at our centre, diagnostic laparoscopy had a 100% sensitivity in identifying intra-abdominal injuries due to peritoneal breach, with 100% negative predictive value [17].

The decision was made to proceed with diagnostic laparoscopy in our patient given haemodynamic stability, retroperitoneal of the bullet on CT imaging, and uncertain bullet trajectory given the distance from the entry point. Laparotomy for abdominal gunshot wounds carries a 22%–41% of postoperative complications and has been associated with unnecessary operations in haemodynamically stable patients [7]. SNOM in haemodynamically stable patients without peritonitis or reduced consciousness carries a failure rate of 7.0% and an in-hospital mortality as low as 0.4% [7]. In our patient, diagnostic laparoscopy confirmed no peritoneal breach, supporting non-operative management of the retroperitoneal bullet.

Conclusion

This case of a multicompartment gunshot wound illustrates the diagnostic and management complexity of ballistic injuries. Gunshot wounds can cause complex laryngotracheal injury and classification systems help to classify their severity and guide management. Diagnostic laparoscopy can aid in determining suitability of stable patients for SNOM of retroperitoneal bullets.

Funding

None declared.

Conflicts of interest

None declared.

References