Surgical Treatment of Calcified Thoracic Herniated Disc Disease via the Transthoracic Approach with the Use of Intraoperative Computed Tomography (iCT) and Microscope-Based Augmented Reality (AR)

Background and Objectives: The aim of this study is to present our experience in the surgical treatment of calcified thoracic herniated disc disease via a transthoracic approach in the lateral position with the use of intraoperative computed tomography (iCT) and augmented reality (AR). Materials and Methods: All patients who underwent surgery for calcified thoracic herniated disc via a transthoracic transpleural approach at our Department using iCT and microscope-based AR were included in the study. Results: Six consecutive patients (five female, median age 53.2 ± 6.4 years) with calcified herniated thoracic discs (two patients Th 10-11 level, two patients Th 7-8, one patient Th 9-10, one patient Th 11-12) were included in this case series. Indication for surgery included evidence of a calcified thoracic disc on magnet resonance imaging (MRI) and CT with spinal canal stenosis of >50% of diameter, intractable pain, and neurological deficits, as well as MRI-signs of myelopathy. Five patients had paraparesis and ataxia, and one patient had no deficit. All surgeries were performed in the lateral position via a transthoracic transpleural approach (Five from left side). CT for automatic registration was performed following the placement of the reference array, with a high registration accuracy. Microscope-based AR was used, with segmented structures of interest such as vertebral bodies, disc space, herniated disc, and dural sac. Mean operative time was 277.5 ± 156 min. The use of AR improved orientation in the operative field for identification, and tailored the resection of the herniated disc and the identification of the course of dural sac. A control-iCT scan confirmed the complete resection in five patients and incomplete resection of the herniated disc in one patient. In one patient, complications occurred, such as postoperative hematoma, and wound healing deficit occurred. Mean follow-up was 22.9 ± 16.5 months. Five patients improved following surgery, and one patient who had no deficits remained unchanged. Conclusions: Optimal surgical therapy in patients with calcified thoracic disc disease with compression of dural sac and myelopathy was resectioned via a transthoracic transpleural approach. The use of iCT-based registration and microscope-based AR significantly improved orientation in the operative field and facilitated safe resection of these lesions.

Alexis retractor efficacy in transthoracic thoracoscopically assisted discectomy for thoracic disc herniations

PURPOSE

A transthoracic anterior or lateral approach for giant thoracic disc herniations is a complex operation which requires optimal exposure and maximal visualisation. Traditional metal rigid retractors may inflict significant skin trauma especially with prolonged operative use and limit the working angles of endoscopic instrumentation at depth. We pioneer the use of the Alexis retractor in transthoracic thoracoscopically assisted discectomy for the first time.

METHODS

The authors describe and demonstrate the technical use of the Alexis retractor during operative cases. Patient positioning, clinical rationale and operative nuances are elucidated for readers to gain an appreciation of the transthoracic approach to thoracic disc herniations.

RESULTS

The advantages of the Alexis retractor include minimally invasive circumferential flexible retraction, facilitation of bimanual instrument use, diminished risk of surgical site infections and reduced rib retraction leading to less postoperative pain.

CONCLUSION

Use of the flexible and intuitive Alexis retractor maximises operative exposure and is an effective adjunct when performing complex transthoracic approaches for thoracic disc herniations.

Costotransversectomy in the Surgical Treatment of Mediolateral Thoracic Disk Herniations: Long-Term Results and Recent Minimally Invasive Technical Adjuncts

Thoracic herniated disks are relatively rare. They account for approximately 2% of all intervertebral herniated disks in large series. Traditional surgery via laminectomy has frequently yielded disappointing results, although the recent literature reports that anterior calcified thoracic herniation was successfully treated with this approach. This issue has encouraged a search for alternatives, such as anterolateral, lateral, and posterolateral approaches to the thoracic spine. From January 2009 to December 2019, we selected 66 patients harboring a symptomatic median-paramedian herniated disk at the level of the thoracic spine, treated at the authors' institutions. The present experience would give further support to the use of costotrasversectomy, along with its "mini-invasive" modifications, as a suitable and safe approach for thoracic disk disease. Although we must admit that endoscopy is likely to become the gold standard of surgical method in the future and that the anterior approach with mini-toracotomy without rib removal will become popular, the future scenario could certainly reserve an important place for the approach we have used in the surgical management of this challenging spinal pathology, mainly because of the approach's versatility and short learning curve.

Posterior Transdural Approach for a Calcified Thoracic Intradural Disc Herniation Using a 3-Dimensional Exoscope: 2-Dimensional Operative Video

This video depicts the removal of an intradural thoracic disc herniation through a purely transdural approach. Thoracic disc herniations are rare, and less than 5% are intradural. Though thoracic disc herniations are removed through a posterolateral or transthoracic corridor, there is literature to support a transdural approach for central herniations.1-3 Although the transdural approach has been selectively adopted for central soft herniations, calcified herniations have been regarded as less suitable.1,2 Intradural thoracic herniations have not been specifically addressed by a transdural approach in the limited literature, though it has been utilized in conjunction with a larger transthoracic approach.4 Our case features a 72-yr-old female presenting with worsening left leg weakness. Computed tomography (CT) identified a multilobulated ventral calcified mass at T11-12. Magnetic resonance imaging was not possible because of an incompatible pacemaker. Our impression was that this likely represented an intradural meningioma though a calcified intradural disc herniation was considered. Given the apparent intradural location, we opted for a transdural approach only via T11-12 laminectomy and a midline dural opening. Dentate ligament sectioning allowed a clear corridor to the now apparent disc material. Postoperative CT confirmed near complete resection, and the patient showed neurological improvement. Ultimately, the transdural approach alone led to complete discectomy while avoiding the morbidity of an invasive transthoracic approach and instrumented fusion. To our knowledge, this is the first video documenting a purely transdural approach for resection of an intradural disc herniation. The patient consented to the surgical procedure and to the use of intraoperative video for education purposes.

How I do it: posterior transdural approach for central soft thoracic disk herniation

BACKGROUND

Thoracic disc herniation (TDH) is a rare condition with severe neurological sequelae. Surgical management is still a matter of debate and challenging.

METHOD

We present a modification of the transdural approach for TDH. The approach has been described in a stepwise fashion, analysing pre-, peri-, and postoperative strategies to improve patients' management and reduce approach-related morbidity.

CONCLUSION

The modified posterior transdural approach represents an effective technique for TDH, minimizing the risk of spinal cord damages, which can dramatically affect the outcome.