Firearm injuries in the spine . eFFective strategy For diagnosis and treatment

The incidence of gunshot wounds to the spine on civilians has increased alarmingly and accounts for 13% to 17% of all traumatic spinal injuries, placing them in third place among the most frequent mechanisms. However, the management of these injuries is still controversial. At present there is little information on the management of these lesions, conservative treatment (non-surgical) being recommended in most publications. Based on the current literature, we propose a procedural protocol aimed at improving the quickness of management, as well as the prognosis of the patient. For this purpose, once the patient is hemodynamically stabilized, the following should be assessed: 1) Stability; 2) Compressive extrusion; 3) Accommodation or not in the discal space, and 4) Contact with CSF. These points are relevant to make the best decision.


INTRODUCTION
The incidence of gunshot wounds in the civil population has been increasing at an alarming rate, and this is currently the third most common cause of traumatic spine lesions, resulting in significant costs for the national economy. However, the management of this type of injury is still controversial.
There is currently very little information available about the management of these injuries, with conservative treatment (non-surgical) being recommended in most publications.
A large number of these articles are based on patients injured by military-type firearms, which are not transferable to the civil popu-lation due to differences in the caliber, speed, material, and size of the projectiles. 1,2 Epidemiology Due to the increasing acquisition of firearms, both legally and illegally, they now account for between 13% and 17% of traumatic spine injuries, putting them in third place among the most common causes. Car accidents are in first place at 50%, followed by falls from heights in second place at 20%.
There are no accurate statistics for our population. Studies published for North American population report that the average age of these victims is between 15 and 34 years, and they are usually male.
Forty-seven percent of the cases are reported as paraplegic and 53% as quadriplegic, 60% occur in the thoracic spine and 48% of the lesions of the cervical spine are complete. [3][4][5]

Initial Management
Patient care should include the established routines for trauma, such as ATLS, among others, with a multidisciplinary management approach due to the high probability of injuries to multiple systems.
Following hemodynamic stabilization, the initial management of these patients should include, as a minimum, an assessment of neurological damage and both a complete interrogation about the type of firearm, the time elapsed, the distance between the attacker and the patient, the number of shootings, and a complete physical examination.
Periodic examinations, preferably by the same doctor, should be conducted to evaluate neurological impairment, as this will determine the subsequent treatment. We suggest marking the entry and exit points of the injury with radiopaque staples for evaluation using radiographs to trace the trajectory of the bullet, as this can help predict the lesions that the patient may have suffered. 6,7 Imaging The first studies of choice are simple radiographs, with 2 orthogonal projections, and computed tomography to adequately evaluate the bone damage sustained and the stability of the spine.
When the stability of the spine is in doubt, dynamic radiographic studies can be performed, whenever there is neurological integrity in the patient. 6,7 ( Figure 1)

Care of the Wound
Currently, the trend is towards more conservative management of the wound. Recent publications have shown no difference between the prevention of infection in patients with extensive debridement versus conservative management, combining it with minimally invasive techniques, imaging studies, and antibiotic therapy. Surgical exploration is only recommended when there are signs of significant vascular lesions.
In cases where the wound penetrates contaminated cavities, prolonged antibiotic therapy is recommended. It has been shown that if the wound is clean, 3 days of antibiotics are sufficient to prevent complications.
Broad-spectrum antibiotic treatment should be started immediately without waiting for culture results, which have been shown to be useless in previous studies, and something that must not be forgotten is anti-tetanus prophylaxis, which is widely recommended. 6,7

Use of Steroids
Until recently, the use of steroids for lesions from firearms was undetermined. In a retrospective review of 252 cases with spinal cord lesions secondary to wounds from firearm projectiles treated with methylprednisolone, in accordance with the NACSIS II protocol, it was concluded that there were no changes in the neurological state of the patients, either in those with complete or incomplete lesions.
A study that compared patients who received methylprednisolone or dexamethasone with those that received no treatment showed no difference in terms of neurological deterioration.
Today, the use of steroids should not be considered for the treatment of patients with spinal wounds from firearm projectiles involving spinal cord lesions given that there are reports that mention that they can increase the rate of complications, especially those related to infections. [8][9][10]

Surgical Decision
The point at which a decision is made that a lesion requires surgery will depend on the characteristics of the injury, the most important being an evaluation of compressive lesions that can be caused by the presence of bone fragments or "chips within the spinal canal", as well as the existence of epidural bruises. (Figure 2)

Extraction of the Projectile
In a study of 153 patients with firearm injuries with retention of the projectile, there was a 9.8% incidence of wound-related sepsis.  In 70 patients, the projectile worked its way out of the body, and in two cases, surgical extraction was indicated, reporting 12.5% sepsis. An increase in incidence is linked to the trajectory of the projectile, being greater in patients whose hollow viscera are penetrated before the spine, as well as in those patients who undergo surgical intervention. [11][12][13] At the cervical spine level, removal of the foreign body is recommended to achieve the best neurological state possible. It has been shown that the benefits from extracting the projectile are not focused as much on improvement of the spinal lesion as on the possible recovery of the adjacent roots.
Because the thoracic spine is the anatomical region with the lowest spinal cord/spinal canal ratio, any foreign body lodged in this zone can cause compression. In the literature, however, neither the neurological outcomes from surgery in these patients, nor in those with complete spinal cord lesion regardless of the segment, demonstrated benefits. Therefore extraction of the bullet between segments T1 and T11 is only performed when there is progressive neurological deterioration.
In the lumbar spine, the spinal canal is wide and the projectile can lodge and migrate. For this reason, extraction is recommended in this region, which includes vertebra T12, in order to prevent an edema rising up from the neurological level. (Figure 3) Finally, in cases where the neurological damage is complete, surgery is only recommended for removal of the projectile, and only when there is instability of the spine that could cause changes in the biomechanics. [11][12][13] (Figure 4)

Stabilization of the Spine
There are four variables to consider for surgical management: a) the neurological status, b) stability, c) the location of the bullet, and d) the level of the lesion.
Currently, surgical indications include: a) persistent fistula of cerebrospinal fluid, b) spinal instability, c) infection, d) neurological deterioration, and e) arteriovenous fistula, though there are more specific indications depending on the anatomic area affected.
A review of cervical spine injuries from firearms conducted in 2014 reported a higher incidence in levels C-6 and C-7. In that study, the following indications were recommended at the cervical level: • Injury to 3 levels and injuries to 2 levels plus 1 pedicle (surgical stabilization); • Injury to 1 or 2 levels (use of orthosis). • At the thoracolumbar spinal level: • Injury to 2 or more levels (thoracolumbar orthosis, fixation, and fusion); • Injury to 1 level (observation).
It is worth noting that while the author found no significant difference, in terms of neurological results, between the use of the halo vest and internal fixation, the factors that did present differences were hematological instability, esophageal injury, and thoracic injury at the time of admission. Factors with more long--term influence included persistent infection, the possible need for diaphragmatic pacemakers, and dural lesions without fistula documented in NMR. 14