1. Background and Importance
An acute traumatic disc herniation without a serious fracture or dislocation is a rare medical event and most often occurs within lumbar and cervical regions [1, 2, 3, 4, 5, 6, 7, 8]. However, its occurrence in the thoracic spine is extremely rare [9, 10, 11, 12]. This can logically be attributed to the support and protection afforded by the rib cage.
Herein, we present a new case with traumatic sequestrated disc at T10-T11 level documented with Magnetic Resonance Imaging (MRI) who was surgically managed with success. After a thorough review of the published medical literature, we found that currently presented case is the 5th reported case with this specific scenario (Table 1).


2. Case Presentation
A 72-year-old female was presented to a local hospital after suffering a fall injury because of losing balance in the bathroom. She slipped and then fell to the ground on her buttock and backbone. While trying to stand up, she immediately became aware of an apparent bilateral lower limb weakness which was more prominent on the right side. She was subsequently transferred to a local hospital where she was conservatively managed after clinically diagnosed with spinal shock considering her normal thoracolumbar radiographs (Figure 1). Two days later at the request of her relatives, she was referred to our facility (Pars Hospital, Tehran, Iran). On admission, we faced an obese woman with high Body Mass Index (BMI: 36Kg/m2). Neurologically, the weakness of both lower extremities (Frankel Grade C) was more prominent on the patient’s right side. This was associated with hyperactive reflexes and right Babinski sign. A vague sensory deficit at the level of the umbilicus was found. 
An MRI undertaken as the second diagnostic tool showed a relatively large right-sided mass anterolateral to the dural sac with mixture of high and low Signal Intensity (SI) on T2-weighted axial images (Figure 2a). Sagittal T2-weighted MRI indicated an isointense mass with upward migration at the level of T10-T11 compatible with sequestrated disc fragment (Figure 2b).
In surgical intervention, the initial step involved a right T10 and T11 segmental pedicle screw insertion. In the next step, subsequent to T10-T11 interlaminar laminectomy, the corresponding disc space and the sequestrated fragments were approached via the right transfacet pedicle-sparing corridor. There, one large and several smaller sequestrated disc fragments embedded below the dura mater were discovered and successfully removed. This was followed by discectomy and interbody fusion with an iliac allograft. Assembling the rods and thightening the nuts in compression were concluding steps of surgical intervention (Figure 3a). Postoperative thoracic spine plain radiographs showed the integrity of the metal construct and interbody graft (Figure 3b). At 3-wek follow-up, she could hardly ambulate with walker. Hopefully, at the 6-month follow-up, she could walk normally (Frankel Grade of E) and her standing lateral radiograph was acceptable (Figure 4). 3. Discussion 
Thoracic disc herniations account for roughly 0.25%-075% of all disc ruptures [13]. Within this region of spinal column, the offending pathologies are generally the formation of the hard discs and the osteophytes which are the final and detrimental consequences of a chronic degenerative scenario [13, 14]. Such pathological anomalies stand in stark contrast to sequestrated soft disc herniations which occur less frequently and within a relatively short period of time [9, 10, 11, 12]. On extremely rare occasions, a pure sequestrated soft disc herniation might occur subsequent to a traumatic event without an apparent vertebral fracture or dislocation [1, 2, 3, 4, 5, 6, 7, 8]. The occurrence of traumatic disc herniations in thoracic spine is extremely rare and confined to only four previously published cases [9, 10, 11, 12].
On MRI, acute traumatic disc Signal Intensity (SI) depends on the water content of the sequestrated disc. The signal intensity of the disc fragment varies from low to high on T2-weighted images. The SI of a traumatic sequestrated disc might be so high that easily be misdiagnosed as an epidural hematoma [5, 8].
Historically, spontaneous regression of a sequestrated thoracic disc herniation has been advocated for the patients with mild neurological deficit [9]. However, for acute Thoracic Disc Herniation (TDH) with neurological deficit, surgery via transfacet pedicle-sparing approach seems to be the most appropriate option [10, 13, 14, 15]. Favorable outcomes depend on early diagnosis and timely surgical intervention.
4. Conclusion
This case highlights the value of emergency MR imaging for patients who have sustained a traumatic spinal cord injury. With consideration of the sequestrated texture of the disc in traumatic TDH; the transfacet pedicle-sparing approach is the choice for removal of the offending pathology. 

Ethical Considerations
Compliance with ethical guidelines
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given her consent for the images and other clinical information to be reported in the journal.

Funding
This research did not receive any grant from funding agencies in the public, commercial, or non-profit sectors. 

Authors' contributions
All authors equally contributed to preparing this article.

Conflict of interest
There are no conflict of interest.

Acknowledgements
The authors acknowledge the patient for her consent to report her medical information.


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