Distraction injury to thoracic spine treated with thoracoscopic dual-rod fixation

Transcription

1 The Spine Journal 6 (2006) Distraction injury to thoracic spine treated with thoracoscopic dual-rod fixation Gregory P. Lekovic, MD, PhD, JD, Eric M. Horn, MD, PhD, Curtis A. Dickman, MD* Division of Neurological Surgery, Barrow Neurological Institute, St. Joseph s Hospital and Medical Center Received 3 February 2005; accepted 30 April 2005 Abstract Keywords: BACKGROUND CONTEXT: Thoracic hyperextension fracture-dislocation is a rare pattern of traumatic spinal injury, typically associated with gross spinal instability and severe neurological deficit. These extremely unstable injuries require internal fixation despite their potentially benign clinical presentation. PURPOSE: We present a patient with a thoracic distraction injury who remained neurologically intact. METHODS: The patient underwent thoracoscopic reduction and anterior fixation of the thoracic spine using a paired screw-rod construct. RESULTS: Postoperatively, the patient remained neurologically intact and had no complications related to his thoracic fixation and fusion. Follow-up radiographs showed maintenance of thoracic alignment and bony fusion. CONCLUSIONS: The endoscopic approach to the anterior thoracic spine was an excellent treatment option for this thoracic distraction injury. Ó 2006 Elsevier Inc. All rights reserved. Hyperextension injury; Thoracic spine; Thoracoscopic fixation; Trauma Introduction Thoracic spine distraction injuries are extremely rare and usually associated with devastating neurological deficits. We present a neurologically intact patient with an unstable distraction injury of the thoracic spine who was treated with thoracoscopic anterior fixation. The patient s clinical history and inpatient and follow-up radiographs were reviewed. Clinical and radiographic follow-up was obtained 7 months after thoracoscopic fixation of the distracted vertebral level. Case report After running a stop sign, a 63-year-old male motorcyclist collided with an automobile at high speed. The patient FDA device/drug status: not applicable. Nothing of value received from a commercial entity related to this manuscript. * Corresponding author. Division of Neurological Surgery, Barrow Neurological Institute, St. Joseph s Hospital and Medical Center, c/o Neuroscience Publications, 350 West Thomas Road, Phoenix, AZ Tel.: (602) ; fax: (602) address: neuropub@chw.edu (C.A. Dickman) was ejected and flipped over the automobile. His posterior thorax hit the trunk of the automobile in a hyperextended position. He was mildly hypotensive but hemodynamically stable at the scene and en route to the trauma room. After primary resuscitation, it was determined that the patient had suffered fractures of the 4th, 5th, 6th, 7th, and 9th ribs; a left femur fracture; an open tibia-fibula fracture on the right; and an open-book pelvic fracture. He had bilateral pulmonary contusions. He was neurologically intact and complained of back pain. His thoracic spine was tender to palpation. Plain thoracic radiographs (Fig. 1) showed a diastasis of the 8th and 9th thoracic vertebral bodies. Further studies, including sagittal reformatted computed tomography scans (Fig. 2), showed distraction of the vertebral bodies of T8 and T9, angulation of T8 on T9 with fishmouthing of the intervertebral disc space, and an avulsion fracture of the body of T8. Magnetic resonance imaging studies showed short tau inversion recovery signal changes through the soft tissues of all three vertebral columns (Fig. 3), including disruption of the anterior longitudinal ligament (ALL) and posterior longitudinal ligament and positive signal changes through the disc space, facet joints, and interspinous ligaments /06/$ see front matter Ó 2006 Elsevier Inc. All rights reserved. doi: /j.spinee

2 G.P. Lekovic et al. / The Spine Journal 6 (2006) Fig. 1. Thoracic plain (A) anteroposterior and (B) lateral radiographs show diastasis of the eighth and ninth thoracic vertebrae. The patient underwent open reduction and internal fixation of the thoracic spine. A thoracoscopic approach was chosen to fixate the spine anteriorly using paired Fig. 2. Sagittal computed tomographic reconstruction of the thoracic spine shows anterior angulation of the T8-T9 disc space ( fish-mouthing ) and diastases. screw-rod instrumentation (Antares, Medtronic Sofamor Danek, Memphis, TN). Surgical technique The patient was placed in the left lateral decubitus position, and T8 and T9 were identified via C-arm fluoroscopy. The patient s right lung was deflated, and a working port was introduced into the right hemithorax. Additional working ports were introduced under direct visualization. The spine was found to be grossly unstable. The T8 and T9 vertebral bodies were exposed by identification of the T8 and T9 rib heads and pedicles. Staples were placed at T8 and T9, and two bicortical screws were placed in each vertebral body. A complete discectomy of the T8-T9 disc space was performed. The disc space was packed with morcellized rib autograft harvested from the T8 and T9 rib heads during dissection. The rods were introduced and a rod compressor was used to reduce the diastasis, after which the construct was locked in place. Two chest tubes were placed, one at the thoracic apex and the other at the costodiaphragmatic recess. Postoperatively, the patient was returned to the intensive care unit. Postoperative imaging confirmed adequate reduction of the diastasis and preservation of anatomical alignment (Figs. 4 and 5). Postoperatively, the patient remained neurologically intact and had no complications related to his thoracic fixation and fusion. On postoperative Day 13, the patient was transferred to a step-down unit. He was discharged

3 332 G.P. Lekovic et al. / The Spine Journal 6 (2006) Fig. 3. (A) Sagittal magnetic resonance imaging with short tau inversion recovery sequence shows high signal intensity in all three columns of the thoracic spine. The anterior longitudinal and posterior longitudinal ligaments are disrupted. (B) Axial image shows widening of the facet joints with abnormal signal intensity. from the hospital on postoperative Day 30. He was fitted with a thoracolumbosacral orthosis and discharged to a rehabilitation unit. Seven-month follow-up radiographs showed maintenance of the thoracic spinal alignment and bony fusion (Fig. 6). Discussion In 12 patients suffering from paraplegia caused by welldocumented pure hyperextension injuries (so-called lumberjack paraplegia ), Denis and Burkus [1] described the typical radiographic findings associated with this mechanism of injury, including anterior widening of the disc space ( fish-mouthing ), sagittal translation of the vertebral column, and anterior avulsion (teardrop) fracture of the vertebral end plate [1]. These findings reflect injury to all ligamentous elements of the spine, including the ALL. In contrast, hyperflexion or pure distraction injuries classically spare the ALL [2]. Hyperextension injuries necessarily involve circumferential ligamentous disruption, with or without associated fractures. Therefore, they are extremely unstable and typically associated with severe neurological deficits [3,4]. Indeed, to our knowledge, this is the first report of a patient remaining neurologically intact after suffering a thoracic hyperextension-distraction injury. In their report of two pedestrian versus auto-distraction injuries of the thoracic spine, Carl and Hash [5] described a patient who also suffered from bilateral disruption of the facet joints. Citing Holdsworth [2] for the contention that distraction injuries rarely disrupt the facet joints, they proposed that their patient experienced a hyperextension moment by being propelled by the striking vehicle. In striking an automobile with his motorcycle and being propelled, we propose that our patient suffered a similar hyperextension force. Our patient s pattern of injury is thus Fig. 4. Intraoperative photographs show (A) placement of the vertebral body and (B) dual-rod fixation after the disc space was packed with locally harvested, morcellized rib autograft.

4 G.P. Lekovic et al. / The Spine Journal 6 (2006) Fig. 5. Postoperative coronal computed tomographic reconstruction shows excellent screw placement with reduction of the diastasis and restoration of normal spinal alignment. consistent with the constellation of findings associated with hyperextension injuries. Radiographic studies demonstrate three-column injuries associated with clear widening of the anterior disc space, ligamentous and facet joint disruption, and coronal translation of the vertebral column (Figs. 1 3). Importantly, at surgery our patient s thoracic spine was grossly unstable. Because ALL and posterior longitudinal ligament are disrupted, these fractures cannot be fixated adequately with posterior hook-rod instrumentation. In fact, posterior distraction with hooks and rods should be avoided because it may risk neurological injury. Compression across the affected segment is required. The options include posterior pedicle screw instrumentation or anterior screw fixation. In our patient, an anterior thoracoscopic screw-rod construct was chosen. A posterior approach with pedicle screw multisegmental fixation could have been considered as an alternative strategy. However, we believe that rigid anterior fixation was preferable to multisegmental posterior fusion given that it could be achieved through a minimally invasive thoracoscopic approach. Thoracoscopy has been applied to a wide range of indications, including tumor resection [6], discectomy [7], and traumatic fractures of the thoracic spine [8 10]. Advantages of the thoracoscopic approach include minimization of pain and morbidity associated with a thoracotomy, such as the postthoracotomy syndrome. As in our patient, who suffered bilateral pulmonary contusions and fractures of right ribs #4, 5, 6, 7, and 9, associated pulmonary and parenchymal injuries and intercostal muscle injuries are common in this patient population, along with the concomitant risks of prolonged ventilatory support, adult respiratory distress syndrome, or both. Thoracoscopic approaches to the thoracic spine can be associated with less postoperative pain, shorter hospitalizations, and earlier mobilization compared with thoracotomies for similar pathology [11,12]. Because our patient suffered severe multiple traumatic injuries, his stay in the intensive care unit was prolonged. His length of stay was unlikely to have been shortened by the thoracoscopic approach. Our decision to proceed with thoracoscopic fixation rather than a combined anteroposterior approach or multisegmental Fig. 6. (A) Anteroposterior and (B) lateral plain follow-up radiographs show the presence of bridging bone and maintenance of spinal alignment.

5 334 G.P. Lekovic et al. / The Spine Journal 6 (2006) posterior pedicle screw fixation primarily was motivated by concern about his diminished pulmonary function. We believe that thoracotomy would have further jeopardized his already compromised pulmonary status and recovery. Conclusion Thoracic hyperextension injuries are a rare pattern of traumatic spinal injury, typically associated with gross spinal instability and severe neurological deficit. We present a patient suffering from thoracic distraction injury who remained neurologically intact. This patient s benign clinical presentation belied the severity of his injury. Clinicians must be aware that thoracic distraction injuries are extremely unstable and require anterior or posterior fixation. This case report demonstrates that thoracoscopic fixation of a thoracic distraction injury is a technically feasible and reasonable treatment option. References [1] Denis F, Burkus JK. Lateral distraction injuries to the thoracic and lumbar spine. A report of three cases. J Bone Joint Surg Am 1991;73: [2] Holdsworth F. Fractures, dislocations, and fracture-dislocations of the spine. J Bone Joint Surg Am 1970;52: [3] Burke DC. Hyperextension injuries of the spine. J Bone Joint Surg Br 1971;53:3 12. [4] Denis F, Burkus JK. Shear fracture-dislocations of the thoracic and lumbar spine associated with forceful hyperextension (lumberjack paraplegia). Spine 1992;17: [5] Carl A, Hash L. Distraction injury of the thoracic spine: report of two cases. J Bone Joint Surg Am 1994;76: [6] Han PP, Dickman CA. Thoracoscopic resection of thoracic neurogenic tumors. J Neurosurg 2002;96(3 Suppl.): [7] Han PP, Kenny K, Dickman CA. Thoracoscopic approaches to the thoracic spine: experience with 241 surgical procedures. Neurosurgery 2002;51(5 Suppl.): [8] Hertlein H, Hartl WH, Dienemann H, Schurmann M, Lob G. Thoracoscopic repair of thoracic spine trauma. Eur Spine J 1995;4: [9] Hertlein H, Hartl WH, Piltz S, Schurmann M, Andress HJ. Endoscopic osteosynthesis after thoracic spine trauma: a report of two cases. Injury 2000;31: [10] Khoo LT, Beisse R, Potulski M. Thoracoscopic-assisted treatment of thoracic and lumbar fractures: a series of 371 consecutive cases. Neurosurgery 2002;51(5 Suppl.): [11] Ferson PF, Landreneau RJ, Dowling RD, et al. Comparison of open versus thoracoscopic lung biopsy for diffuse infiltrative pulmonary disease. J Thorac Cardiovasc Surg 1993;106: [12] Landreneau RJ, Hazelrigg SR, Mack MJ, et al. Postoperative painrelated morbidity: video-assisted thoracic surgery versus thoracotomy. Ann Thorac Surg 1993;56: