Penetrating Spine Injuries

KEY RECOMMENDATIONS

1. Consider early surgery in penetrating spinal cord injury for progressive or incomplete neurological deficits in the setting of continued mass effect upon the spinal cord if surgeon and treatment facility capabilities allow.
2. Patients with concomitant hollow-viscus injuries and penetrating spinal cord injuries should be treated with broad-spectrum anti-microbial coverage for 48 hours to 10 days, depending upon the level of contamination of the injury and control of associated any cerebrospinal fluid leak.

Surgical Intervention

Spinal cord injuries from penetrating mechanisms are more likely to produce complete neurologic deficit than those sustained through blunt force.4,49 With penetrating mechanisms, spinal cord injury can occur through direct damage in the projectile tract or via cavitation injury, whereby shock waves imparted on the tissue surrounding the path of the projectile and rapid changes in pressure damage tissue.50 The two latter forces can produce severe irrecoverable spinal cord injuries, even in cases where the projectile does not penetrate the spinal canal. In these injuries staged debridement of the wound may be required given the cavitary injury to soft tissue. Surgical indications may include progressive neurological deterioration, incomplete deficit (particularly if a missile or fragment is still within the canal) or the presence of a CSF leak. If surgery is undertaken, good dural closure is paramount with an attempt at “water tight” repair. Anterior and oblique entry to the lumbar and lower thoracic spine are at increased risk of infectious complications due to traversal of hollow viscus organs.51 In these cases the patient’s infectious risk and neurological status are key factors in determining the need for and timing of surgical intervention. There is no evidence from the current conflict to support the concept that a complete SCI from a penetrating mechanism has a significant chance of clinical improvement with surgical intervention.

Treatment

In 2010, Klimo et al., led a tri-service literature review of articles on penetrating spinal injury sustained in combat and provided treatment recommendations.52 Based on this review of both military and civilian literature, they concluded that the role of decompression in promoting neurologic recovery remains ambiguous.52 For an incomplete injury with continued canal compromise, decompression, if attempted, should ideally occur within 24-48 hours. Additionally, persistent and high-flow CSF-cutaneous and pleural fistulae should be surgically treated. The authors recommended consideration of spinal stabilization at the time of initial surgery in cases with associated instability.52 Because the unique natural histories of these may render typical blunt injury classification systems less applicable, the treatment of these injuries relies largely on clinical decision making of the operative physician.5,53 In these situations, surgeons should consider: available resources, expertise of the operative team, infectious risks and the patient’s neurological status when determining the need for and timing of operative intervention in theater.

CT scans remain the study of choice for penetrating spinal injuries as MRI is typically not as helpful or available in the deployed setting. Additionally, they can be contraindicated given the ferromagnetic activity of the fragment and bullet material.54 CT myelogram can be considered in patients with occult or persistent CSF leaks that are not easily localized based on exam or plain CT.

Appropriate antibiotic coverage and duration may often prove controversial. In 2011 the Infectious Disease Society and Surgical Infection Society released a joint guideline for the prevention of infection associated with combat-related injuries.55 This combined statement recommended Cefazolin 2 gm IV q8hrs for 24-72hrs for penetrating spine injuries without evidence of contamination. Fragments passing through contaminated viscus structures such as the esophagus or colon require extended spectrum intravenous anti-microbial coverage of enteric organisms for longer periods of time. Potential antibiotic regimens include Ancef 2g IV q6-8hrs and Metronidzole 500mg IV q8-12hrs; Cetriaxone 2 g IV q24hrs and Metronidazole 500 mg IV q 8-12hrs. Patients with penicillin or cephalosporin allergies may be treated with Vancomycin 1g IV q12hrs + Ciprofloxacin 400 mg IV q8-12hrs. This working group recommended a minimum antibiotic duration of 5 days or until any CSF leak is closed. Steroids should not be considered as therapy for patients with penetrating spinal cord injuries.56