Introduction

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  Combat-related penetrating spine injuries (PSIs) are due to firearms and explosive devices, most notably improvised explosive devices (IEDs).

  
  
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  PSIs account for up to 25% of all spinal cord injuries, of which approximately half present with complete paraplegia and more than one-quarter are associated with other injuries. ¹ An article comparing penetrating and blunt military spine injuries in the recent U.S. military conflicts (Operation Iraqi Freedom and Operation Enduring Freedom) reported that of 598 injured service members, 104 (17%) sustained spinal cord injuries, comprising 10% of blunt injuries and 38% of penetrating injuries (p < 0.0001). ²

  
  
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  The thoracic spine accounts for the majority of injuries, with the lumbosacral and cervical spine following in second and third, respectively. ^{1 , 3}

  
  
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  Given the relationship of kinetic energy (KE), mass (m), and velocity (v) (KE = 1/2mv²), the most critical factor affecting the destructiveness of a projectile is its velocity, ⁴ making the high-velocity PSIs seen in combat settings particularly devastating. ^{3 , 5} Therefore, it is not surprising that patients with military PSI in general have a worse neurologic injury on presentation and have less potential for neurologic recovery than those with closed spinal cord trauma. ³

Indications

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  Fig. 24.1 depicts a treatment algorithm for combat-related PSI.

  
  
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  Incomplete spinal cord injury with mass lesion in the spinal canal, with or without progressive neurologic deficit

  
  
  
  
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    While the literature is mixed regarding the exact benefit of decompressive surgery (usually in the form of multilevel laminectomies), most still favor operative intervention in a medically stable patient with an incomplete spinal cord injury and evidence of persistent cord compression such as bone or metallic fragments within 24–48 hours of the initial injury. ^{1 , 3 – 10} An incomplete spinal cord injury may exist without impingement on the spinal canal due to the energy released to the surrounding structures by the passage of the projectile (i.e., “shock wave”). In this scenario, surgery is not recommended.

  
  
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  CSF—cutaneous/pleural fistula

  
  
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  Prolonged CSF leakage and its concomitant infectious risks constitute a definitive surgical indication in PSI ^{1 , 3} ( Fig. 24.2 ).

  
  
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  Fragment-induced nerve root compression

  
  
  
  
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    Patients with both clinical and radiographic evidence of either bony or foreign body–induced nerve root compression should have the involved roots decompressed, ideally in the first 24–48 hours after injury. ¹

  
  
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  Spinal instability

  
  
  
  
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    Since the majority of civilian PSIs are from low-muzzle velocity handguns and knife wounds, biomechanical instability is not, in general, an issue. As such, these patients require no instrumentation and/or fusion during operative intervention. ^{1 , 3 , 9 , 10} In combat PSI, however, the projectiles involved (bullets or fragments from an explosive device) have a greater energy that can be dissipated to the surrounding anatomic structures, thus increasing the likelihood of spinal instability. With high-velocity ballistic trauma, the rate of instability can approach 20% and is most common in injuries with a side-to-side trajectory involving the facet joints bilaterally ⁷ ; however, the concept of spinal stability remains nebulous and ultimately rests on a case-by-case consideration of multiple clinical and radiographic findings with clinical intuition playing an equally strong role ( Fig. 24.3 ).

    
    
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    If the patient has a transgastrointestinal and unstable spinal injury, we recommend that instrumentation be postponed until the patient has completed a full course of intravenous antibiotic therapy and, if necessary, the abdomen has been thoroughly debrided and washed out by a general surgeon.

  
  
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  Recent literature has established that the following clinical scenarios are not indications (in and of themselves) for operative intervention:

  
  
  
  
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    Complete spinal cord injury (in the absence of spinal instability or CSF leakage) ( Fig. 24.4 ) ^{1 , 3 – 10}

    
    
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    Wound debridement/closure (in the absence of gross wound contamination) ¹¹

    
    
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    Copper- and/or lead-based fragments

    
    
    
    
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      Given how rare heavy metal toxicity is with PSI, the composition of a fragment should not dictate operative intervention based on current evidence. ³

Disclaimer: The views expressed in the following text (or presentation, manuscript, etc.) are those of the authors and do not necessarily reflect the official policy or position of the Department of the Army, Department of the Navy, Department of Defense, nor the U.S. Government.