Combined Posterior-Anterior Interbody Fusion in the Management of Traumatic Lumbosacral Dissociation: A Case Report and Review of Literature

Abstract

Traumatic lumbosacral dissociation is a unique, but well-documented, phenomenon that generally stems from high-energy impact injuries to the lower lumbar spine. Patients typically present with complicated and multisystem injuries with wide-ranging neurological deficits below the level of trauma. This presents stark challenges regarding the diagnosis, management, and surgical correction technique utilized. In this study, we present the case of a 21-year-old, morbidly obese, male patient that presented after a traumatic motor vehicle accident with L5-S1 lumbosacroiliac dissociation, cauda equina syndrome, and left lower extremity monoplegia. The degree of disruption warranted a 360° approach, we opted for an anterior lumbar interbody fusion followed by a posterior, lumbar interbody, short segment fusion. We review the case and relevant literature of similar lumbosacral dissociation studies with their management options and outcomes. Due to the rare nature of these devastating injuries, there remains wide variability in their management, with a combination of open anterior and posterior approaches resulting in variable long-term outcomes. The management of these rare injuries will require appropriate consideration of the patient's unique etiology, coexisting injuries, and radiological imaging in deciding surgical stabilization techniques.

Keywords: anterior fusion; lumbosacral dissociation; posterior fusion; short segment fusion; trauma.

Figure 1. Computed tomography (CT) revealing traumatic lumbosacral dissociation

Axial (left) and coronal (center) CT sections revealing sacral pelvic dissociation evident by the widening of the sacroiliac (SI) joints bilaterally. Sagittal (right) CT image revealing the widening of the L5-S1 disc space with posterior listhesis and widening of the L5-S1 facet joints with a fracture facet (not seen on the image).

Figure 2. Post sacroiliac stabilization

Axial (left), coronal (center), and sagittal (right) CT images revealing post insertion of the left sacroiliac (SI) screw. The SI screw appears to occupy the sacral vertebral body.

Figure 3. Intraoperative lateral X-ray following the anterior lumbar interbody fusion

Intraoperative lateral X-ray view of the L5-S1 region revealing the anterior interbody cage with screws; the largest cage size was inserted, which was marginally displaced up to the posterior vertebral body edge, with the screws getting good purchase without the cage going into the spinal canal.

Figure 4. Posterior exposure revealing the avulsed cauda equina and L5-S1 defect

The dura was torn completely and the cauda equina was avulsed and could be seen emerging from the L5-S1 defect with few filaments in the paraspinal space. The Kocher clamp is on the L5 spinous process and the dissector is within the avulsed nerve root filaments.

Figure 5. L5-S1 defect with open dura

The spinous process of L5 can be seen superiorly with the nerve hook under the avulsed roots in the distracted space between L5 and S1. The nerve roots were gently re-inserted within the canal and duraplasty with Duragen, fibrin glue was performed in an onlay manner, tacking the edge of the Duragen to the adjacent dura and covering the defect. Duragen: Integra LifeSciences, New Jersey

Figure 6. Postoperative follow-up magnetic resonance imaging (MRI - left upper and lower) and computed tomography images (CT - right upper and lower quadrants)

MRI follow-up at three months, with the canal widely decompressed and an evident defect at L5-S1 without any evidence of a pseudomeningocele. CT scans revealed anterior and posterior implants in place.

Figure 7. Lateral L-S X-ray at six months

Postoperative X-ray revealing the anterior and posterior implant in a good position at six months