Unilateral Biportal Endoscopic Transforaminal Approach for Chronic Central Thoracic Disc Herniation: A Video Case Report and Surgical Technique Description
Article information
Abstract
To demonstrate the feasibility and highlight key technical nuances of a unilateral biportal endoscopic (UBE) transforaminal approach for resecting chronic, centrally calcified thoracic disc herniation (TDH). Central TDH is a rare and technically demanding condition due to the narrow thoracic canal, proximity to the spinal cord, and frequent calcification in chronic cases. Minimally invasive techniques that reduce spinal cord manipulation and preserve posterior stabilizing structures are therefore preferred. A 74-year-old woman presented with lower back and left leg pain, sensory disturbance, and gait impairment. Magnetic resonance imaging revealed a centrally calcified TDH at T10–11 with significant spinal cord compression. The lesion was approached via a transforaminal UBE route under continuous irrigation, providing a direct lateral working corridor for optimal visualization and controlled decompression. The calcified and adherent disc was progressively thinned and delicately dissected from the dura using an angled sharp hook and fine endoscopic instruments, minimizing cord manipulation. Postoperative imaging confirmed complete decompression, and the patient showed marked neurological recovery without complications. For centrally located, calcified TDH, the transforaminal UBE approach enables effective decompression while minimizing spinal cord retraction and preserving posterior elements. The accompanying video provides a detailed step-by-step demonstration of the procedure to enhance its safety and reproducibility.
CASE PRESENTATION
A 74-year-old woman presented with longstanding bilateral pelvic pain and progressive gait disturbance, accompanied by sensory impairment in the left leg. The pain had persisted for approximately one year, while sensory symptoms and gait dysfunction had emerged over the preceding three months. Neurological examination revealed hyperreflexia in the left lower extremity, deep tendon reflexes graded 2+/3+, and ankle clonus on the left side. Impaired balance was evident during ambulation. Conservative management failed to alleviate pain or halt neurological function. Preoperative magnetic resonance imaging (MRI) and computed tomography demonstrated a calcified central disc herniation at the T10–11 level, causing significant spinal cord compression (Figure 1). Considering the patient’s advanced age and the elevated risks associated with open thoracic approaches, a unilateral biportal endoscopic (UBE) transforaminal discectomy was selected to achieve adequate neural decompression while minimizing tissue disruption and preserving posterior spinal structures.
Preoperative radiologic imaging. (A) Sagittal computed tomography (CT) scan demonstrating a centrally calcified T10–11 disc causing canal compromise; the white circle highlights intradiscal calcification. (B) Axial CT scan at T10–11 showing a centrally located calcified disc within the spinal canal. (C) Axial T2-weighted magnetic resonance imaging (MRI) demonstrating severe ventral cord compression at T10–11. (D) Sagittal T2-weighted MRI showing a centrally extruded disc; the white dashed circle indicates marked thoracic cord compression.
SURGICAL TECHNIQUE
The procedure was performed under general anesthesia with the patient positioned prone. A right-sided transforaminal approach was employed. Two portals were established as laterally as feasible along the planned trajectory, ensuring avoidance of obstruction by the transverse process or rib. In this case, the portals were placed approximately 6–7 cm lateral to the midline, with an interportal distance of approximately 3 cm. The docking point was identified at the junction of the lateral margin of the left T10–11 facet joint and the adjacent rib.
Following portal placement, a partial lateral facetectomy was performed to expose the surgical corridor. Indigo carmine dye was injected for discography to enhance visualization and accurately delineate the disc tissue. To facilitate safer and more complete removal of the calcified disc material, the posterolateral aspect of the T10–11 vertebral body was meticulously drilled, thereby expanding the working space beneath the disc.
Following annulotomy, the sequestrated disc fragment adherent to the ventral aspect of the thecal sac was meticulously dissected from the dura using a sharp hook, mobilized inferiorly with a curved curette, and subsequently removed. No dural tears occurred, and restoration of dural pulsation was confirmed. Epidural bleeding was controlled with hemostatic agents, and a Hemovac drain was inserted prior to wound closure to complete the procedure.
RESULTS
The patient experienced complete resolution of neurological symptoms without any postoperative complications. Follow-up MRI performed two days after surgery confirmed complete lesion removal and adequate spinal cord decompression (Figure 2). The patient was discharged in stable condition 72 hours postoperatively. No spinal instability or symptom recurrence was observed at the three-month follow-up.
Postoperative radiologic images. (A) Sagittal computed tomography (CT) scan showing enlargement of the right T10–11 foramen following partial resection of the right superior articular process and pedicle; the white dashed arrow indicates the resection site. (B) Axial CT scan demonstrating a widened transforaminal corridor at T10–11 (White arrow). (C) Axial T2-weighted magnetic resonance imaging (MRI) confirming resolution of ventral cord compression at T10–11. (D) Sagittal T2-weighted MRI confirming complete removal of the central disc herniation and restoration of the anterior cord contour; the white circle marks the previous compression site.
DISCUSSION
Thoracic disc herniations (TDHs) are rare, comprising approximately 0.25%–0.75% of all symptomatic disc herniations and less than 1%–2% overall, based on surgical and imaging series [1,2]. However, autopsy and imaging studies suggest that incidental TDHs may be more prevalent, occurring in up to 11%–37% of asymptomatic individuals [3]. Central TDHs pose distinct challenges due to the narrow thoracic spinal canal, the spinal cord’s limited tolerance for retraction, and calcification in chronic lesions, which complicates discectomy. Traditional open approaches, such as anterior thoracotomy or posterolateral exposures, provide access but are associated with substantial morbidity, including extensive muscle dissection, spinal destabilization, and postoperative pain [4-6].
The UBE technique has emerged as a minimally invasive alternative, offering high-definition visualization, continuous irrigation, and enhanced instrument mobility, all with minimal tissue disruption [7]. As skilled surgeons continue to broaden its therapeutic scope, substantial research and progress have been made in the thoracic spine, including the removal of ossification of the ligamentum flavum [8]. However, the application of this technique to centrally calcified TDHs remains largely uncharted.
This video case report demonstrates a transforaminal UBE approach for the removal of a chronic central calcified TDH at the T10–11 level. Previous reports have described full-endoscopic techniques for TDH [9,10]. To date, no published cases have documented the use of the UBE technique for centrally calcified TDHs.
This approach provides a direct lateral corridor, minimizes spinal cord retraction, and preserves posterior elements, offering a safe and effective option for managing complex thoracic pathology. The surgical technique challenges the necessity of traditional open surgery. However, its efficacy and safety remain unestablished for the mid- and upper thoracic levels, cervical spine, and symptomatic ossification of the posterior longitudinal ligament. Further research is required to expand its indications.
This video provides valuable educational content for spine endoscopic surgeons, illustrating detailed technical steps and decision-making processes involved in performing a UBE transforaminal discectomy for central calcified TDH. The clear procedural demonstration enhances reproducibility and facilitates adoption or refinement of this minimally invasive technique by spine endoscopic surgeons in clinical practice.
CONCLUSION
The UBE transforaminal approach shows great potential to become a viable, minimally invasive surgical strategy for addressing challenging central calcified thoracic disc herniations.
WRITTEN TRANSCRIPT
00:11 Case Presentation
A 74-year-old woman presented with progressive gait disturbance and sensory disturbance in the left leg for one year. Neurological examination showed hyperreflexia, increased deep tendon reflexes, and ankle clonus in the left lower extremity.
00:27 Preoperative MRI & CT Images
Preoperative imaging revealed a calcified central disc herniation at T10–T11 with significant spinal cord compression.
00:39 Perioperative Setting
The procedure was performed under general anesthesia with the patient in the prone position. The surgeon stood on the patient’s right side. Two portals were created approximately 6–7 cm lateral to the midline.
01:00 Partial Facetectomy
Once we established triangulation between the scope and instruments at the docking point—which was located at the right lateral aspect of the T10–T11 facet joint—we proceeded with a partial lateral facetectomy. This step was necessary to open up and better expose the surgical corridor, allowing improved access to the target area.
01:46 Surgical Instrument
We used a 3-mm diamond round burr to carefully remove the bone, which allowed us to work precisely in the small surgical area. During the procedure, any bleeding that occurred was effectively controlled using radiofrequency coagulation to maintain a clear surgical field.
02:15 Discography
Indigo carmine dye was injected during discography to help enhance visualization, making it easier to clearly distinguish the disc tissue and surrounding structures for safer surgical manipulation.
02:27 Additional Bone Work
After completing the discography, we took extra care to further visualize the annulus, which helped us clearly outline the surrounding tissues. With this improved view, we were then able to carefully advance our approach medially, gradually exposing the lateral margin of the dura to ensure precise and safe dissection.
03:18 Annulotomy
Using a No. 15 blade, the annulus was carefully excised to remove the degenerated tissue. Following this, radiofrequency coagulation was applied around the surrounding area to meticulously clean the surgical field, control any minor bleeding, and prepare the site for the subsequent steps of the procedure.
04:12 Partial Corpectomy
To make the removal of the calcified disc material safer and more thorough, we carefully drilled the posterolateral aspect of the T10–T11 vertebral body. This step helped us to widen the working space beneath the disc, giving us better access and more room to maneuver our instruments without putting unnecessary pressure on the spinal cord.
05:02 Discectomy and Detachment of Posterior Longitudinal Ligament
After carefully removing the disrupted annulus using a blunt hook, we proceeded to gently detach the dura from the posterior longitudinal ligament using an upward-facing curette, ensuring minimal tension on the surrounding tissues.
06:49 Central Disc Debulking
Subsequently, the disc material within the central disc space was debulked using up-bite forceps. To improve visualization during this step, a scope retractor was gently used to elevate the dura upward, which helped maintain a clear surgical field and facilitated safer decompression.
07:19 Careful Dissection of Sequestered Disc Mmaterial Adherent to the Dura
Subsequently, to carefully separate the chronic disc material that was firmly adherent to the dura, a sharp hook was employed to meticulously dissect and peel the tissue away from the dural surface. Throughout this delicate step, great care was taken to avoid any dural tears or damage, as such complications could lead to cerebrospinal fluid leakage or other neurological issues. To enhance precision and control, a two-handed technique was utilized, where the scope retractor was used in one hand to gently elevate and protect the dura, while the sharp hook in the other hand carefully freed the adherent disc material. This coordinated approach allowed for safer and more effective dissection in this challenging area.
Notes
Conflicts of Interest
PK, a member of the Editorial Board of Journal of Minimally Invasive Spine Surgery & Technique, is the author of this article. However, he played no role whatsoever in the editorial evaluation of this article or the decision to publish it. The other author has no conflict of interest to declare.
Funding/Support
This study received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
Informed Consent
Patient consent was waived due to the retrospective nature of this study and the complete anonymization of all clinical data and imaging.