Evolution and current status of surgical management of thoracic disc herniation - A review

Thoracic disc herniations (TDH) are uncommon compared to cervical and lumbar disc herniations. Surgical treatment of TDH can be challenging due to the anatomical constraints and the high risk of morbidity due to proximity to the thoracic spinal cord. Moreover, the selection of appropriate surgical approach depends on various factors such as the size and location of disc herniation within the spinal canal, spinal level, presence or absence of calcification, degree of spinal cord compression, and familiarity with various approaches by the treating surgeon. While there is agreement that posterolateral approaches can be used to treat posterolateral and central soft disc herniation, there is a lack of consensus on the best surgical approach for central calcified and giant calcified TDH where an anterior approach is perceived as the best option. There is increasing evidence that support the safety and efficacy of posterolateral approaches even for central calcified and giant calcified TDH. This review highlights the evolution of surgical management for TDH based on the past and current literature and the author's experience at his institution.

Comparison of Anterior Approach and Posterior Circumspinal Decompression in the Treatment of Giant Thoracic Discs

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

The treatment of giant thoracic disc herniation (gTDH)remains challenging for surgeons worldwide because of its large volume and calcified or ossified nature and the limitations of the prior small-sample-size, single-center studies reporting comparative effectiveness. We aim to compare the anterior decompression and spinal fusion (ASF) and posterior circumspinal decompression and spinal fusion (PCDF) for patients with myelopathy due to gTDH in the largest study to date by sample size.

METHODS

Preoperative and postoperative functional status, surgical details, and complication rates were compared between the 2 groups.

RESULTS

A total of 186 patients were included: 63 (33.9%) ASF and 123(66.1%) PCDF. The PCDF group had significantly shorter operation duration (163.06 ± 53.49 min vs. 180.78 ± 52.06 min, P = 0.032) and a significant decrease in intraoperative blood loss(716.83 mL vs. 947.94 mL, P = 0.045), and also a shorter hospital length of stay (LOS) and postoperative LOS (6 vs. 7, P = 0.011). The perioperative complication rate (13.8% vs. 28.6%, P = 0.015) and surgery-associated complication rate(13.0% vs. 27.0%, P = 0.018) were significantly higher in the ASF group. A higher rate of complete decompression was achieved in the PCDF group. There were no observed significant differences in changes in functional status between the 2 groups.

CONCLUSION

PCDF for central or paracentral gTDHs is a highly effective and reliable technique. It can be performed safely with a low complication rate. If either procedure can adequately excise a central or paracentral gTDH, a PCDF approach may be a better option.

Use of Cannulated Reamers to Facilitate Thoracic Diskectomy Using a Minimally Invasive Retropleural Thoracotomy Approach-Surgical Technique

BACKGROUND

The surgical treatment of symptomatic thoracic disk herniations is technically challenging. In the past decade, a minimally invasive retropleural thoracotomy approach has become more popular to treat this pathology. However, efficient bone removal to safely perform the diskectomy and spinal cord decompression is difficult with this technique because of the small incision size and long working distance in the thoracic cavity and the proximity of the compressed thoracic cord.

OBJECTIVE

To describe a novel surgical technique for performing a thoracic diskectomy using a minimally invasive lateral approach using cannulated reamers to facilitate bone removal.

METHODS

This technique was used in 7 consecutive patients who presented with thoracic myelopathy from a thoracic disk herniation. First, a standard lateral minimally invasive retropleural approach to the thoracic spine was performed. Partially threaded guide wires were placed in the posterior aspect of the vertebral bodies adjacent to the affected disk space, and sequential cannulated reamers were passed over the guidewires to perform partial corpectomies. The posterior annulus, posterior longitudinal ligament, and herniated disk material were then resected using Penfield dissectors and Kerrison rongeurs to complete the decompression.

RESULTS

All 7 patients who underwent thoracic diskectomy using this approach had stable or improved neurologic function postoperatively. There were no complications related to the use of the cannulated reamer technique.

CONCLUSION

The use of cannulated reamers provides a simple and efficient method for safe bone removal to facilitate minimally invasive thoracic diskectomy using a lateral approach. This is an easily reproducible technique using commonly available equipment.

[Surgical treatment of herniated thoracic discs using transthoracic extrapleural approach]

OBJECTIVE

To analyze the results of herniated thoracic disc resection via transthoracic extrapleural approach.

MATERIAL AND METHODS

The study included 16 patients with 18 symptomatic herniated thoracic discs wo underwent transthoracic extrapleural surgery. In 11 cases, clinical pattern of disease was represented by myelopathy with radicular or axial pain syndrome. Five patients had radiculopathy alone. Median localization of hernias was observed in 8 (44.4%) cases, paramedian hernias - in 10 (55.6%) cases. There were 10 (55.6%) ossified hernias, 5 (27.7%) giant, 10 (55.5%) large and 3 (16.6%) medium hernias.

RESULTS

In most patients, VAS score of pain syndrome decreased by 2-6 points (mean 3.6). In 4 patients, this value remained the same. Among 11 patients with myelopathy, regression of conduction disorders in 1 year after surgery was achieved in 9 (82%) cases including complete recovery in 6 (55%) patients (Frankel E, Nurick - 0-I). In 2 patients, neurological status was equal to preoperative one. In all cases, the follow-up examination confirmed total removal of compressive substrate and found no signs of spine instability. Surgery time varied from 80 to 210 min (mean 161), blood loss - from 300 to 800 ml (mean 378 ml). Two patients had transient neurological deterioration. There was damage to dura mater in 4 cases. Intercostal neuralgia was observed in 3 patients.

CONCLUSION

While retaining the advantages of open thoracotomy, transthoracic extrapleural approach is less traumatic, allows complete spinal cord decompression, minimizes the risk of iatrogenic spinal cord injury and avoids certain postoperative complications.

Risk factors associated with post-operative neurological deterioration in patients with thoracic disc disorders with myelopathy

PURPOSE

Post-operative neurological deterioration (ND) is a severe complication. However, limited literature exists on the ND in thoracic disc disorders with myelopathy (TDM). This study describes the risk factors of neurological deterioration in TDM with instrumentation and fusion.

METHODS

A single-centre review of TDM with instrumentation and fusion during 2006-2019 was performed. Post-operative neurological deterioration was defined as the deterioration of pre-existing neurological function or the appearance of new neurological symptoms. Patients were then grouped into two groups depending on neurological deterioration (ND group) or not (non-ND group). Demographics, radiographic parameters, and surgical characteristics were compared between the two groups.

RESULTS

A total of 257 cases were included, and neurological deterioration occurred in 16 (6.23%) cases. Multivariate analysis revealed spinal canal occupancy ratio > 75%, U-shaped compressed spinal cord in axial MRI, calcified herniated disc, anterior approach, and intra-operative blood loss > 1500 mL were associated with ND. Ten patients (62.5%) had complete neurological recovery within six months, and four patients (25%) had progressive neurological function improvement and equal or better than pre-operation within nine months.

CONCLUSIONS

The rate of neurological deterioration is 6.23%, and a higher spinal canal occupancy ratio, U-shaped compressed spinal cord, calcified herniated disc, anterior approach, and massive intra-operative blood loss were associated with neurological deterioration. Long-term outcomes of neurological deterioration are favourable, and 62.5% of patients experienced complete neurological recovery within six months. Patients with TMD who undergo surgery should be properly informed of the potential risks of neurological deterioration, despite its usually transient nature in most patients.