Transforaminal Thoracic Interbody Fusion (TTIF) for Treatment of a Chronic Chance Injury
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- Huang, R.C., Meredith, D.S. & Taunk, R. HSS Jrnl (2010) 6: 26. doi:10.1007/s11420-009-9138-3
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Multiple anterior and posterior approaches to the thoracic disc space have been reported. However, we are not aware of any previous reports describing a transforaminal approach for thoracic disc release and interbody cage placement. In this case report, we describe a method to perform transforaminal thoracic interbody fusion (TTIF), which is an adaptation of an established lumbar fusion technique (transforaminal lumbar interbody fusion). Key differences between the two procedures are discussed. A 24-year-old woman presented after sustaining a T11-12 Chance fracture that had been treated in a brace. She had severe, debilitating pain and a rigid segmental kyphotic deformity of 38°. The patient was treated 3 months post-injury with T10-L1 fusion with anterior release and interbody fusion with cage placement at T11-12. Anterior column release and fusion were performed via a transforaminal approach. The patient had anatomic reduction of deformity, solid arthrodesis, and relief of pain at 1-year follow-up. The TTIF approach permits access to the anterior column of the thoracic spine for the purpose of reduction of deformity and interbody fusion with reduced morbidity compared to anterior–posterior surgery.
Flexion-distraction injuries or Chance fractures may occur as purely ligamentous injuries, purely bony injuries, or combined injury patterns. Associated anterior column compression fracture may occur. When promptly recognized and treated, Chance fractures without neurologic injury carry an excellent prognosis for functional recovery. Acute surgical reduction and stabilization with one-level constructs provides excellent results . On the other hand, treatment of chronic Chance injuries is more difficult  because rigid deformity may develop and anterior column collapse may result in relative anterior column deficiency upon reduction of the deformity. In cases of rigid kyphotic deformity, access to the anterior column for the purpose of soft tissue release, reduction of deformity, anterior column support, and enhancement of fusion rate may be useful.
Commonly employed techniques for achieving access to the thoracic disc space include thoracoabdominal, open transthoracic, thoracoscopic, lateral extracavitary, costotransversectomy, and transpedicular approaches. Anterior approaches offer excellent exposure and visualization of the disc space but are associated with significant pulmonary  and incisional morbidity . Posterior approaches not only offer more limited disc space access with less morbidity but also require significant posterior soft tissue dissection, particularly when lateral extracavitary or costotransversectomy approaches are utilized.
The purpose of this article is to report a case of treatment of a chronic Chance injury at T11-12 with rigid kyphotic deformity using a novel technique. Anterior column release and implantation of an interbody fusion cage were performed via a thoracic adaptation of transforaminal lumbar interbody fusion (TLIF)/transforaminal thoracic interbody fusion (TTIF).
The patient is an active 24-year-old female who was a restrained passenger in a high-speed motor vehicle accident. She was treated at a trauma center where she was diagnosed with a “T12 compression fracture,” pulmonary contusions, a liver laceration, and multiple rib fractures. Treatment of all injuries was nonsurgical, and the “compression fracture” was treated in a thoracolumbar orthosis for 8 weeks.
Upon removal of the brace at 8 weeks, the patient was referred to physical therapy. Twelve weeks after injury, the patient continued to have severe thoracolumbar pain with activity, when lying supine or prone, and with sitting. She was unable to participate in athletic activity or yoga as she had prior to injury. The patient presented to our hospital for a second opinion 10 weeks post-injury.
Physical exam showed a visible thoracolumbar gibbus with chronic hyperpigmented skin changes. Active or passive thoracolumbar extension caused severe pain. The patient was neurologically intact. Surgery was indicated at that time to address the patient’s pain, loss of function, and deformity.
Based on the rigidity of the kyphosis on preoperative hyperextension films, it was anticipated that anterior column release would be required to correct the deformity. Furthermore, it was anticipated that reduction of the deformity would create relative anterior column deficiency due to loss of anterior vertebral body height at T12. Therefore, the planned surgery included decompression of T11-12, release of the T11-12 disc space, and instrumented fusion of T10-L1 with placement of an interbody cage at T11-12. In order to avoid the morbidity associated with an anterior approach to T11-12, the anterior column was released and an interbody cage was placed via a bilateral posterior transforaminal approach—an adaptation of the TLIF approach popularized by Harms and Rolinger .
Surgery was performed 3 months post-injury. Intraoperatively, the deformity was very rigid. Soft tissue and scar overlying the dura centrally and interposed between the distracted facet joints were removed in order to facilitate reduction and to prevent spinal cord compression upon reduction. Laminectomy was not performed. The lateral pars and inferior facet of T11 were partially resected in a lateral-to-medial direction until the lateral aspect of the dura was exposed. Access to the T11-12 disc space was achieved between the dura medially and the fatty tissue overlying the pleura laterally. The T11 nerve roots exited horizontally, lying cephalad to the disc space. Disc access and release was performed bilaterally. No effort was made to resect or transect the anterior longitudinal ligament.
There are many limitations to the TTIF technique. Because accessing the disc space via the TTIF approach is time consuming, the technique is ideally suited for cases in which the deformity or pathology to be addressed is limited to a small number of levels. The use of an interbody cage as a fulcrum to facilitate reduction of kyphosis would be ineffective in patients with osteoporosis. The anatomy of the rib heads would render TTIF more difficult at levels above the thoracolumbar junction. Partial rib head resection may be necessary to access the disc at higher levels. Finally, the approach affords limited access to the floor of the spinal canal for decompression of midline compressive lesions.
Use of the TTIF technique in this patient offered several advantages compared to other previously described techniques for accessing the thoracic disc space. The TTIF approach offers decreased pulmonary morbidity compared to open or laparoscopic transthoracic approaches. Open transthoracic and thoracoabdominal approaches are associated with significant approach-related morbidity. Posterior soft-tissue dissection is reduced compared to lateral extracavitary or costotransversectomy approaches. The pedicle is not removed, as in some transpedicular approaches; therefore, pedicle screw instrumentation can be utilized. Use of TTIF, in this case, allowed anterior column release for anatomic correction of a rigid deformity with a short construct, placement of anterior column support, and optimization of fusion rate via interbody arthrodesis.