Treatment strategy on traumatic mid-lumbar spondyloptosis with concomitant multiple injuries: A case report and literature review

Spondyloptosis in the clinic is rarely reported. We herein present a 47-year-old female, who suffered from a crush injury directly by a heavy cylindrical object from the lateral side. She was diagnosed to have traumatic L3 spondyloptosis with multiple traumas. Staged surgical procedures were conducted and a three-year follow-up was obtained. Eventually, normal spinal alignment was restored, and neurological deficits were gradually improved. At three years follow-up, the motor strength scores and function of the sphincters were incompletely improved. Previously published reports on traumatic lumbar spondyloptosis were reviewed and several critical points for management of this severe type of spinal injury were proposed. First, thoracolumbar and lumbosacral junction were mostly predilection sites. Second, numerous patients involving traumatic lumbar spondyloptosis were achieved to American Spinal Injury Association grade A. Third, lumbar spondyloptosis was commonly coupling with cauda equina injury. Finally, the outcomes were still with poorly prognosis and recovery of patients was correlation to spondyloptosis severity. Based on this case report and literatures review, we highlighted that the spinal alignment restoration relying on staged operations and following rehabilitation hereof are both important once facing with multiple traumas. Furthermore, we suggested to perform routine CT angiography during lumbar spondyloptosis to justify whether there are large vessel compression or injury.


Introduction
According to Meyerding classification, spondyloptosis is described as a unique Grade V spondylolisthesis, which presents as beyond 100% subluxation and dislocation during two vertebrae. 1 Although spondyloptosis cases are rarely reported in the clinic, this injury still needs to be stressed in view of the poor prognosis and outcomes due to the complete loss of spinal column alignment. 2 The characteristics of spondyloptosis mainly include congenital dysplasia of the spinal column, high-energy trauma, infective disorders, ever-evolving degeneration, and neurofibromatosis. 3e5 For traumatic spondyloptosis, traffic accidents and fall from height are major causing factors. 6 Traumatic spondyloptosis is rigidly associated with neurological deficits, resulting in paraplegia in about 80% of cases. 7 Herein, we report a rare severe case of traumatic midlumbar spondyloptosis with multiple traumas. Staged surgical operations were performed. At three years follow-up, the patient's neurological function was partially improved. This report also reviewed related literatures on traumatic lumbar spondyloptosis and proposed several specific points on the management of midlumbar traumatic spondyloptosis.

Case report
A 47-year-old female sustained a crush injury by a heavy cylindrical object from her right side. The patient complained of severe lower back pain, right shoulder pain, and thoracalgia. Radiological examinations in local hospital revealed multiple injuries, comprising L 3 vertebra fracture-dislocation, scapular fracture, rib fractures, and left femoral shaft fracture (Fig. 1).
The patient was managed following the advanced trauma life support protocol in the local hospital and then was transferred to our hospital for further treatment. Making an accurate diagnosis commonly depends on the stability of vital signs and a comprehensive evaluation rely on damage control. On admission, the patient was conscious and hemodynamically stable, classified as American spinal injury association (ASIA) grade A. In this patient, injury severity score (ISS) and abbreviated injury score (AIS) reached 43 and 15 respectively so that regarded as severe injury. Physical examination found shortened, swollen, and malformed left lower extremity. There exists paraparesis, including limited activity in the bilateral lower extremity and dysfunctional urination and defecation. Perirectal sensation diminished and anal sphincter tone was absent. Spinal CT indicated a complete anterior spondyloptosis of L 3 to inferior vertebral body, and concomitant fractures. The L 3 vertebra was downright parallel to L 4 vertebra (Figs. 2AeC). L 3 vertebral fracture was confirmed by three-dimensional reconstruction (Fig. 2D). But the anterior dislocation of lumbar vertebra associated with vertebral body fracture and the position with large vessels required to be further clarified. As a result, compression of both inferior vena cava and abdominal aorta was implied on consecutive CT axial planes and CT angiography (Figs. 2E and F). Blood test showed an elevated level of D-dimer.
The strategy of staged surgical procedures was drafted in concept of orthopedic damage control. The L 3 spondyloptosis was closely adjacent to the inferior vena cava and abdominal aorta, leading to thrombosis of the left common iliac vein. The risk of perioperative incidence of pulmonary embolism (PE) was significantly increased. Venography demonstrated filling defect at the origin of the inferior vena cava and the lumen stenosis was about 90% (Supplementary video). Therefore, inferior vena cava filter was implanted through the internal jugular vein (Figs. 3A and B). To stabilize the spinal alignment, posterior bilateral pedicle screw fixation and rods construction were performed on segments L 1 , L 2 , L 4 , and L 5 vertebral bodies in prone position (Figs. 4AeC). Intraoperatively it was found that the cauda equina was injured and right nerve root of L 3 was lacerated. A tiny tear of the dura mater was noted, which was covered with gelatin sponge. Layer by layer watertight sutures were ensured. Fortunately, there was no postoperative cerebral spinal fluid leakage. Satisfactory spinal sagittal balance was restored.
Postoperative CT and three-dimensional reconstruction of CT angiography demonstrated that the main body of the fractured L 3 vertebrae was retracted a little while at the expense of graver compression of the abdominal large vessels (Figs. 4DeF).
A II stage surgical intervention was performed on postoperative day 5. After anesthesia, the patient was placed in right lateral prone position, and the femoral shaft fracture was fixed by anterograde intramedullary interlocking nail. Further anterior spinal exposure was carried out through left anteriorlateral approach. Intraoperatively, it was observed that the abdominal aorta was elevated by the dislocated vertebrae body of L 3 . Then the completely fractured L 3 vertebrae body was removed en bloc (Fig. 5A) and a cage of 26 mm in diameter with cancellous bone from L 3 vertebrae was implanted between L 2 and L 4 (Fig. 5B). Reconstruction of the anterior sagittal spinal balance was enhanced by pedicle screw system, which has been implanted into L 2 and L 4 . Postoperative radiography (Figs. 5C and D) demonstrated a restored stability of the spine and decompression. The patient was discharged and referred for further rehabilitation in a local hospital.
Scheduled postoperative course was obtained. The patient returned for removal of the inferior vena cava filter at 1 month after the primary surgery. At 6-month follow-up, the patient's neural compromise had a gradual improvement. The patient had motor strength scores of 4/5 in left hip flexors and knee extensors, and 3/5 in foot dorsiflexion and plantar flexion, while 2/5 in right lower extremities (Figs. 6A and B). However, perirectal sensation was still diminished accompanied with overflow incontinence and relaxation of the anal sphincter tone. Sensation at the right lower limb (right medial and left lateral zone) disappeared. Plain radiography (Fig. 6C) and CT sagittal reconstruction (Fig. 6D) indicated a stabilized spinal alignment balance.

Discussion
In this report, we described a rare severe traumatic mid-lumbar spondyloptosis case with multisystem damages. The shear-type mechanism of injury was caused by lateral crushing from the right side. The fractured L 3 vertebral body was dislocated in front of L 4 vertebra, meanwhile, the L 2 vertebral body was displaced laterally with respect to the L 3 vertebra body. In this rare situation, there were two types of spondyloptosises including L 2/3 in coronal plane and L 3/4 in sagittal plane, which had not been reported in the literatures before. The fractured L 3 vertebral body was a free bone fragment without any connection to adjacent vertebraes. In this special situation, vertebral displacement cannot be completely corrected through single posterior surgical approach. The staged surgical strategy combined with anterior-posterior pedicle screw systems was the definitive fixation plan for this challenging traumatic spondyloptosis cases. Segmental of spinal fusion is determined by the severity of the traumatic spondyloptosis. In this case, posteriorlateral fusion in L 1-5 levels and anterior fusion in L 2-4 levels were applied respectively. Stabled segmental fixation systems restored the spinal sagittal and coronal balance to facilitate rehabilitation.
According to the available literatures, a total of 40 traumatic lumbar spondyloptosis cases (from year 1999e2020) have been reported. 1,2,6,8e29 Their demographics and clinical characteristics are shown in Table 1. Herein, the age range of patients reported previously was 3e56 years. Among them, males contributed the majority, 82.5%. Motor vehicle accident (25%), fall from height (25%), and crushing accident (22.5%) were the main causes. The injury mechanism is attributed to severe shear force and hyperextension. Moreover, thoracolumbar junction (25%) and lumbosacral junction (27.5%) were mostly predilection sites which may be closely association with structural development. About 35% patients with traumatic lumbar spondylopsis had concomitant severe injuries. In addition, about 75% patients involved in traumatic lumbar spondyloptosis achieved ASIA grade A and only a few of them escaped the disaster of paraplegia of the lower extremity. Furthermore, lumbar dislocation-fracture was commonly coupled with cauda equina injury, leading to micturition and defecation problems. Collectively, surgical interventions, involving anterior, posterior, or combined anterior-posterior pedicle screw systems, are the most common approaches for spondyloptosis management. Finally, the prognosis was poor and the recovery of patients was correlated with the spondyloptosis severity.        Spondyloptosis leads to severe spinal mal-alignment, sagittal or coronal planes dislocation. 2,14 The occurrence position of spondyloptosis could be unequivocally on cervical, thoracic, lumbar, or even sacral spine through radiological examinations, resulting in serous neurological deficits. 18,30e32 Current surgical interventions are commonly conducted on reduction of spine column as well as decompression and stabilization of associated dislocation-fracture segments. Notably, the following rehabilitation trainings are important to the grade of neurological improvements, whereas, the recovery outcomes tend to be patient specific. Based on previously published studies, conservative treatment is not recommended for spondyloptosis irrespective of symptoms status. A persistent unstable spinal alignment eventually leads to spinal deformity (kyphosis or lordosis), which might be associated with low back pain. 16,33 Meanwhile, early surgical reduction may be beneficial by improving neurological symptoms.
Spondyloptosis located on mid-lumbar spine is sparse in the clinic. Considering that the anatomic situations of large vessels such as abdominal aorta and inferior vena cava are closely contiguous to lumbar vertebrae. 18 The major issue is to imperil large vessels in abdomen on extrusion and even rupture threat. Overall anterior, posterior or lateral dislocation of superior vertebral body for inferior vertebra exacerbate volume jostling at the same segmental axial plane. Lumen stenosis and congestion of large vessels is advantageous to thrombosis formation which is causative for pulmonary embolism attack that serves as the most troublesome for survival. Moreover, bony fragments from vertebra fractures are easily embed in these vessels that lead to unbearable results. Therefore, routine CT angiography is suggested to evaluate whether large vessel injury exist in terms of the considerations above.
Traumatic mid-lumbar spondyloptosis with polytrauma is a challenging situation to manage in the clinic. Herein, we presented a case of a complete L 3 spondyloptosis combined with polytrauma through the whole body. The current report mainly focused on spondyloptosis and combined injuries according to the concept of damage control orthopaedics. The spinal alignment restoration relying on individual staged operations and subsequent rehabilitation are the key points. For patients with multiple injuries, especially those with spinal fractures and dislocations, it is necessary to pay attention to the first choice of early appropriate spinal intervention and to evaluate the degree of pressure near the vessels by computed tomography angiography before operation. These patients are mostly at a high risk for deep vein thrombosis and pulmonary embolism. It is recommended to implant intravenous vena cava filter through internal jugular vein. Meanwhile, for patients with better functional recovery, an observation of the posterolateral spinal fusion in the follow-up process is essential to avoid failure of spinal implant fixation. Taken together, based on the major premise of stable vital signs, strategy of staged surgical procedures for spondyloptosis is dominate in terms of orthopedic damage control. Early spinal alignment reestablishment is commonly regarded as the superior choice relative to the fixation of limb fractures in spondyloptosis which accompanied with concomitant multiple injuries. Ultimately, the imperative of postoperative rehabilitation exercise is also critical for the functional recovery.

Ethical statement
This study was approved by the Institution Review Board of Qilu Hospital of Shandong University and written informed consent was obtained from this patient.

Declaration of competing interest
The authors declare that they have no competing interests.

Author contributions
Lin Cheng and Cheng Qiu conducted literature research,collected data, and drafted and revised the manuscript. Xin-Yu Liu and Xi-Guang Sang revised the manuscript. All authors read and approved the final version of manuscript.