This retrospective cohort study included patients treated for spinal gunshot wounds at Latin American institutions between 2014 and 2022. This study was conducted in accordance with the ethical standards as stated in the Declaration of Helsinki as revised in 2013. The study was approved by the institutional review board of Autonomous University of Nuevo Leon (OR23-00001). All patients were anonymized with an identification number, and the investigators were blinded to their identity. The requirement for informed consent was waived due to the retrospective design of this study and use of anonymous data.

Eligible participants included all adult civilian patients aged ≥18 years who were treated for gunshot wounds to the spine. Patients who died prior to arrival assessment or were transferred from another center after the first 48 hours of trauma, received antibiotic prophylaxis at another center and/or lacked a record of this information, and had gunshot wounds no deeper than the soft tissue or a paravertebral bullet without a bone trajectory were excluded.

Data on the following variables were documented: (1) Demographic and clinical characteristics on arrival: age, sex, comorbidities, level of spinal injury, time from injury to admission (in hours), systolic blood pressure (SBP), Glasgow Coma Scale (GCS) score, neurological status according to the American Spinal Injury Association Impairment Scale (AIS), and associated injuries. (2) Nature of the spinal gunshot injury: type of firearm (low or high velocity), type of wound (clean or dirty), bullet trajectory, and retention of bullet fragments (spinal canal, disc, vertebral body, posterior arch, and soft tissue). This study categorized wounds as either “clean” or “dirty” in accordance with the classification proposed by de Barros Filho et al. [8], which was based on hollow viscus perforation. Additionally, gunshot wounds were characterized according to the high likelihood of contamination from skin flora, clothing debris, and other external particles introduced during the injury. (3) Penetrating trauma and spinal injury treatment: duration of antibiotic administration and antibiotic coverage, surgical debridement, bullet removal, use of steroids, and spinal injury management (nonoperative or operative treatment). (4) Penetrating trauma infectious complications: spinal infectious complications, including pyogenic spondylodiscitis, spinal abscess, and meningitis, and non-spinal infectious complications, including intra-abdominal abscess and sepsis. Additionally, cases of nosocomial infection were documented. (5) The follow-up duration (months) was recorded for all patients as part of the study variables.

Categorical variables were expressed as numbers and frequencies and analyzed using the chi-square method or Fisher’s exact test. Numerical variables were expressed as mean or median, depending on whether they were normally or non-normally distributed, respectively, with their measures of dispersion presented as standard deviation (SD) for normally distributed data and range for non-normally distributed data. Student t-test was used to compare normally distributed numerical variables between two groups, whereas the Mann-Whitney U test was used for non-normally distributed numerical variables. A p-value of <0.05 indicated statistical significance. To facilitate comparisons according to the duration of antibiotic prophylaxis, 72 hours was used as the cutoff point in accordance with the findings of the study conducted by de Barros Filho et al. [8]. This is a particularly relevant reference in the context of our specific geographic region. All statistical analyses were performed using the IBM SPSS Statistics ver. 25.0 software (IBM Corp., Armonk, NY, USA).

A total of 384 patients treated for spinal gunshot wounds across 16 spine centers in Latin America were retrospectively analyzed, with data from 2012 to 2016 being collated. These cases included contributions from institutions in Mexico, Colombia, Venezuela, Brazil, and Argentina, with the majority of patients (83.1%) treated at centers in Mexico. After excluding patients who had been transferred from another center after the first 48 hours of trauma and those who had received antibiotic prophylaxis at another center, 292 patients were ultimately included in the final analysis.

The population consisted mostly of adult male civilian patients (n=251; 86.0%) with a mean age of 32.6 years (SD=11; range, 18–65 years) without comorbidities (n=157; 53.8%). Most injuries were located in the thoracic spine (n=135; 46.2%), followed by the lumbosacral (n=95; 32.5%) and cervical (n=62; 21.2%) spines. Most patients had trauma-related non-spinal injuries (n=234; 80.1%) and neurological deficits on arrival (n=207; 70.9%). Hypotension (SBP <90 mm Hg) was documented in 137 patients (46.9%), but only 35 (12.0%) arrived with a GCS score of <8. More than half of the sample presented with a severe neurological deficit (AIS A or B: n=150; 53.4%). The average follow-up duration was 13.6 months (SD=15.3; range, 0–108 months). Additional sample characteristics are presented in Table 1.

The sample consisted solely of civilian gunshot wounds, most of which were caused by low-velocity firearms (n=247; 84.6%), followed by high-velocity wounds (n=45; 15.4%). The projectile trajectory indicated that most injuries compromised the spinal canal, creating penetrating or perforating wounds (n=183; 62.7%).

A total of 55 patients (18.8%) suffered from multiple gunshot wounds. A third of the sample exhibited hollow viscus perforation (n=101; 34.6%), whereas a quarter (n=74; 25.3%) were classified as having dirty wounds (Fig. 1). In 218 patients (74.6%), the bullet was retained within the body. The final bullet location was the spine in 33.2% of the patients, with the following distribution: spinal canal (n=43; 14.7%), vertebral body (n=27; 9.2%), posterior arch (n=22; 7.5%), and intervertebral disc (n=5; 1.7%).

Among patients with gunshot wounds to the spine, 20 (6.8%) developed infectious complications, among whom which 3 (1.0%) developed spinal infections, 6 (2.1%) developed non-spinal infections (five cases with abdominal sepsis and one case with meningitis secondary to brain injury), and 11 (3.8%) developed wound infections.

Spinal infections included pyogenic discitis in one patient and meningitis in two patients. In one patient, meningitis developed from cervical trauma with esophageal laceration in which a bullet was lodged in the spinal canal, whereas in another patients, meningitis developed from an abdominal dirty gunshot wound with hollow viscus perforation and spinal canal compromise (Fig. 2). Lumbar pyogenic discitis occurred in a patient with a lumbar dirty gunshot wound.

Most patients included in the study sample (n=274; 93.8%) received an early course of antibiotic prophylaxis. The median duration of antibiotic therapy was 8 days (range, 0 to 35 days), with 14 patients (4.8%) receiving treatment for <72 hours. Most patients received an extended course of antibiotics. Among these patients, 63 (21.5%) received extended antibiotic therapy due to infectious complications (nosocomial infection or trauma-related infection).

Most patients (n=140; 47.9%) received intravenous broad-spectrum antibiotics, covering gram-positive, gram-negative, and anaerobic bacteria. The median duration of antibiotic prophylaxis was significantly increased in patients with dirty wounds (p<0.001) caused by high-velocity projectiles (p=0.001). The characteristics of antibiotic administration are summarized in Tables 2 and 3.

In 44 patients (15.1%), the bullet was successfully removed from the canal without complications. In contrast, all three patients who developed spinal infection did not undergo bullet removal from the canal. However, we found that the development of spinal infection was not associated with bullet removal (chi-square test, p=0.463). Among the two patients with meningitis, one had projectile lodged in the spinal canal, whereas another had the same lodged in the vertebral body. In the patient with discitis, the bullet was lodged in the soft tissue.

Surgical debridement of the entry site or bone debridement in the spinal projectile path was performed in 39 patients (13.4%) to remove devitalized tissue and prevent further contamination. The development of wound infection was not associated with surgical debridement (chi-square test, p=0.167).

Most cases were managed nonoperatively (n=221; 75.7%). Among the 71 patients who received surgical treatment, 48 (67.6%) were treated with decompression, whereas 46 (64.8%) underwent fixation through a posterior approach.

The use of steroids for spinal cord injury was documented in 14 patients (4.8%).

A total of 273 patients who received antibiotics were included in the comparison of the duration of antibiotic therapy. Table 4 compares patients according to an antibiotic administration threshold of more or less than 72 hours, along with relevant study variables, including both independent variables and outcomes. Notably, our findings showed that none of the patients who did not receive antibiotics exhibited hollow viscus perforation. These patients were categorized as having clean wounds determined based on the individual judgment of their respective spine specialists.

Bivariate analysis of independent variables showed a significant difference in the proportion of patients with a GCS score of <8 based on whether the duration of their antibiotic therapy was more or less than 72 hours (p=0.011).

The incidence of spinal infectious complications was not associated with the duration of antibiotic administration. However, a significant difference the proportion of non-spinal complications was observed, with those who received antibiotics for <72 hours showing a higher rate of complications than did those who received antibiotics for >72 hours (p=0.032).