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Penetrating spine trauma


Introduction

Penetrating injuries to the spine are often caused by gunshot wounds (GSWs). Most of the literature supporting the management guidelines of GSWs to the spine stem from military and combat medicine. The overall incidence of civilian GSWs has increased and causes 13% to 17% of all traumatic spine injuries, but this varies depending on the country. Civilian GSWs typically occur with low-caliber weapons but still create devastating injuries. Civilian spinal GSWs are typically caused by low-velocity (<1000 ft/second) projectiles, and battle-related injuries by high-velocity firearms (2000–3000 ft/second) often involving multiple spinal levels. This condition represents a long-term impairment and disability, especially in younger individuals. Functional outcomes from penetrating injuries are worse than those from blunt trauma based on the likelihood of having a spinal cord injury. The surgical intervention of patients with penetrating spine trauma is widely debated, and there is currently a paucity of high-level evidence supporting a standard of surgical care. The heterogeneity of injury patterns in penetrating spine injuries makes the classification and treatment algorithm an extremely challenging task. In this chapter, we present a case that demonstrates an example of surgical management of a penetrating GSW to the spine with resulting conus injury.

Example case

  • Chief complaint: gunshot wound to the spine

  • History of present illness: This is a 39-year-old man who was brought to the emergency department after sustaining a gunshot wound to the lower back. The patient was fully conscious and presented with a lower limb paraplegia. Imaging was concerning for a GSW to the spine ( Fig. 29.1 ).

    Fig. 29.1, Preoperative postcontrast computed tomography (CT) bone windows. (A) Axial, (B) coronal, and (C) Sagittal views images demonstrating a metallic artifact (bullet) within the posterolateral spinal canal at the L3-4 level. The bullet had fractured the left lamina and broke into the left L3-4 zygapophyseal joint. No spondylolisthesis is evident. In addition, there is disruption of the posterior ligament complex as the bullet went across the interlaminar ligament (ligamentum flavum), facet capsular ligament, and posterior longitudinal ligament (PLL). The bullet and its fragments occupy the whole anteroposterior diameter of the spinal canal on the left and displace the cauda equina nerve roots to the right.

  • Medications: none

  • Allergies: no known drug allergies

  • Past medical and surgical history: none

  • Family history: noncontributory

  • Social history: multidrug use and ethanol abuse

  • Physical examination: awake, alert, oriented to person, place, and time; cranial nerves II–XII intact; bilateral deltoids/biceps/triceps 5/5; interossei 5/5; iliopsoas/knee flexion/knee extension/dorsi, and plantar flexion 0/5

  • Reflexes: 2+ in bilateral biceps/triceps/brachioradialis; 3+ in bilateral patella/ankle; positive Babinski; negative Hoffman; L3 sensory level; no rectal tone

  • Ignacio Barrenechea, MD

  • Neurosurgery

  • Grupo Gamma

  • Rosario, Santa Fe, Argentina

  • Luis Rodrigo Diaz Iniguez, MD

  • Orthopaedic Surgery

  • Hospital Angeles Lindavista

  • Mexico City, Mexico

  • Patrick C. Hsieh, MD

  • Neurosurgery

  • University of Southern California

  • Los Angeles, California, United States

  • Alexander R. Vaccaro, MD, PhD, MBA

  • Orthopaedic Surgery

  • Thomas Jefferson University

  • Philadelphia, Pennsylvania, United States

Preoperative
Additional tests requested

  • L-spine sitting x-rays

  • Hepatitis B/C, HIV, syphilis testing

  • Cardiology evaluation

  • Trauma survey

  • Infectious disease evaluation

L-spine x-ray

  • Toxicology panel

  • CT abdomen/pelvis

Trauma survey
Surgical approach selected L3 hemilaminectomy, removal of bullet fragments, duraplasty, possible L3-4 fusion L3-4 laminectomy, removal of bullet and fragments, possible L3-4 posterior fusion if instability present L3-4 laminectomy, removal of bullet with duraplasty, L3-4 posterior spinal fusion, possible lumbar drain placement Delayed surgery 6–8 weeks, L3-4 laminectomy

  • Surgical approach if 55 years old

  • Surgical approach if 80 years old

  • Same approach

  • Conservative management

  • Same approach

  • Same approach

  • Same approach

  • Same approach

  • Same approach

  • Conservative management

Goal of surgery Cauda equina decompression, avoid infection/fragment migration/toxic metal Remove fragments, decompress neural elements Cauda equina decompression, removal of mass effect, dura repair Cauda equina decompression, removal of mass effect, dura repair
Perioperative
Positioning Prone on Wilson frame Prone Prone on Jackson table Prone
Surgical equipment

  • Fluoroscopy

  • Surgical microscope

Fluoroscopy

  • IOM (MEP/SSEP/sphincter)

  • Fluoroscopy

  • Surgical microscope

  • O-arm

  • Lumbar drain

  • IOM

  • Fluoroscopy

  • Lumbar drain

Medications Maintain MAP Steroids Steroids, liposomal bupivacaine None
Anatomical considerations Cauda equina, pars interarticularis, lumbar facets and pedicles, dura Neurological tissue, pedicles, intervertebral disc Thecal sac, cauda equina nerve roots Thecal sac, cauda equina nerve roots
Complications feared with approach chosen Spinal instability, CSF leak, neurological deterioration Progressive neurological injury, fragment migration, infection Cauda equina nerve injury, enlarging dural injury Cauda equina nerve injury
Intraoperative
Anesthesia General General General General
Exposure L3 L3-4 L3-4 L3-4
Levels decompressed L3 L3-4 L3-4 L3-4
Levels fused L3-4 L3-4 L3-4 None
Surgical narrative Position prone, x-ray to plan incision, midline incision, fascia incised and opened underneath skin edge with monopolar cautery, detach left lumbar muscles off L3 lamina, hemilaminotomy under microscopic visualization with high-speed bur, keep ligamentum flavum as dural protection during bone work, resect ligamentum flavum with angled Kerrison rongeurs, bluntly dissect dura to identify dural defect, carefully dissect bullet fragments off cauda equina roots, explore extent of L3-4 facet and L3 pedicle damage, L3-4 pedicle screw fusion if signs of instability are found, pack area with fat and fibrin flue if cannot primarily repair, layered closure with no drain, maintain bullet and bullet fragments for ballistic investigation Position prone, midline skin incision, plane dissection, laminectomy over bullet, remove bullet and fragments, evaluate disc injury as well as pedicles and stability, L3-4 pedicle screws if there is instability, irrigate wound, layered closure Position prone, baseline MEP/SSEP with anal sphincter, expose L3-4 level and confirm with x-rays, placement of L3-4 pedicle screw tracts, L3-4 laminectomy with left L3-4 facetectomy, removal of extradural bullet fragment, explore thecal sac, examine dura integrity, open dura and remove bullet fragments under microscopic visualization, close dura with water-tight closure and perform duraplasty if needed, arthrodesis and placement of bone graft and osteo biologics at L3-4, dural only and fibrin flue, drain placement in epidural space, topic vancomycin and tobramycin, wound closure in layers, lumbar drain placement if concerned about closure Position prone, plan incision based on x-ray, minimally invasive approach, subperiosteal dissection, confirm correct levels, laminectomy by trying to identify edges of visible dura, tack dura back with sutures, remove encapsulated bullet fragments, close dura as bed as possible with patch if needed, place lumbar drain through separate stab incision, layered closure, place patient on bed rest for 3–5 days with <15 cc/hr drainage, observe for infection
Complication avoidance Use ligamentum flavum to protect dura during bone work, fuse if instability is found, primary dural repair if possible, attempt primary repair of dura Explore disc injury, posterior fusion if instability present Remove extradural bullet first, explore dural integrity, duraplasty if needed, lumbar drain if CSF leak rate concern is high Delay surgery 6–8 weeks to allow for assessment of neurological function and encapsulation of bullet, minimally invasive approach, lumbar drain placement
Postoperative
Admission ICU Floor vs. ICU Floor Floor
Postoperative complications feared Spinal instability, CSF leak, neurological deterioration Infection, progressive neurological injury CSF leak, medical complications CSF leak, infection, cauda equina nerve root injury
Anticipated length of stay 5 days 2 days 5–7 days 5–7 days
Follow-up testing CT L-spine within 48 hours of surgery

  • L-spine x-ray after surgery

  • CT L-spine within 48 hours

  • EMG 2 months after surgery

L-spine x-rays before discharge, 3 months, 6 months, 12 months, annually after surgery L-spine x-rays after surgery, 6 weeks, 3 months, 6 months, annually after surgery
Bracing None None None None
Follow-up visits 3 weeks, 6 weeks, 3 months, 1 year after surgery 2 weeks after surgery 2–3 weeks, 6 weeks, 3 months, 6 months, 12 months, annually after surgery 2 weeks, 6 weeks, 3 months, 6 months, annually after surgery
CSF , Cerebrospinal fluid; CT , computed tomography; EMG , electromyography; ICU , intensive care unit; IOM , intraoperative monitoring; MEP , motor evoked potential; SSEP , somatosensory evoked potential.

Differential diagnosis

  • ▪

    Spinal stab wounds

  • ▪

    Explosive-related injury

  • ▪

    Penetrating spinal cord injury

  • ▪

    Spinal shock

  • ▪

    Epidural hematoma

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