Percutaneous Endoscopic Thoracic Discectomy in the Upper and Midthoracic Spine: A Technical Note

Evolution, Current Trends, and Latest Advances of Endoscopic Spine Surgery

Background: The aging of the population in developing and developed countries has led to a significant increase in the health burden of spinal diseases. These elderly patients often have a number of medical comorbidities due to aging. The need for minimally invasive techniques to address spinal disorders in this elderly population group cannot be stressed enough. Minimally invasive spine surgery (MISS) has several proven benefits, such as minimal muscle trauma, minimal bony resection, lesser postoperative pain, decreased infection rate, and shorter hospital stay. Methods: A comprehensive search of the literature was performed using PubMed. Results: Over the past 40 years, constant efforts have been made to develop newer techniques of spine surgery. Endoscopic spine surgery is one such subset of MISS, which has all the benefits of modern MISS. Endoscopic spine surgery was initially limited only to the treatment of lumbar disc herniation. With improvements in optics, endoscopes, endoscopic drills and shavers, and irrigation pumps, there has been a paradigm shift. Endoscopic spine surgery can now be performed with high magnification, thus allowing its application not only to lumbar spinal stenosis but also to spinal fusion surgeries and cervical and thoracic pathology as well. There has been increasing evidence in support of these newer techniques of spine surgery. Conclusions: For this report, we studied the currently available literature and outlined the historical evolution of endoscopic spine surgery, the various endoscopic systems and techniques available, and the current applications of endoscopic techniques as an alternative to traditional spinal surgery.

The Transaxillary Approach as a Direct Route in the Management of Upper Thoracic Spine Pathology: A Technical Note with Case Series

This retrospective case series of prospective data aims to describe the transaxillary approach for the treatment of upper thoracic spine pathology. Various surgical techniques and approaches have been reported across the literature to address upper thoracic spine pathology, including the cervicothoracic approach, anterior transsternal approach, posterolateral approach, supraclavicular approach, and lateral parascapular approaches. These techniques are invasive. A minimally invasive, less morbid, and direct access approach to the pathology of the upper thoracic spine has not been reported in the literature. Patients with pathology affecting the first thoracic vertebra up to the sixth thoracic vertebra were classified into the upper thoracic spine group. Patients with pathology below the sixth thoracic vertebra were excluded. Patients not having a minimum follow-up of 12 months were also excluded. The study analyzed 18 patients. The mean preoperative modified Japanese Orthopedic Association score was 7.2±1.44, which improved to 10.16±1.2 (p<0.05). The majority (14/18) of the patients had an excellent outcome. Three patients had good outcomes, and one patient had a fair outcome. Five cases of intraoperative dural leak were recorded, and one patient had postoperative neurological deficit. The transaxillary approach is a safe, viable, muscle-sparing, and minimally invasive approach for ventral pathologies of the upper thoracic spine.

Development of an Endoscopic Spine Surgery Program: Overview and Basic Considerations for Implementation

Endoscopic spine surgery (ESS) is an innovative technique allowing for minimally invasive, direct visualization of spinal abnormalities. The growth of ESS in the United States has been stunted by high start-up costs, low reimbursement rates, and the steep learning curve associated with mastering endoscopic techniques. Hergrae, we describe the current state and future direction of ESS and provide key action items for ESS program implementation.

Transforaminal endoscopic thoracic discectomy: surgical technique

The major challenge inherent to the surgical treatment of thoracic disc herniations is that the disc herniation is often ventral to the spinal cord. Posterior approaches are difficult and dangerous due to the morbidity associated with retraction of the thoracic spinal cord. A ventral approach is not feasible due to the thoracic viscera. A lateral transcavitary approach is the standard for treating ventral thoracic disc pathology but is also quite morbid. Transforaminal endoscopic spine surgery has emerged as a minimally invasive technique for treating thoracic disc pathology and it can be performed in the outpatient setting even with the patient awake. Advances in endoscopic camera technologies as well as the availability of specialty instruments that can be used down a working channel endoscope has now made a myriad of spine pathologies accessible to the minimally invasive spine surgeon. The transforaminal approach and the angled endoscopic camera are an ideal combination for creating a technical advantage to accessing thoracic disc pathology in a minimally invasive fashion. The principal challenges to the approach are needle targeting and understanding the endoscopic visual anatomy. Many surgeons interested in pursuing this technique are often deterred by the burden of the cost and time it takes to become adept and performing the technique. Detailed here are the authors' step-by-step technique and illustrative video that demonstrate transforaminal endoscopic thoracic discectomy (TETD).

A modified percutaneous transforaminal endoscopic surgery for central calcified thoracic disc herniation at the T11/T12 level using foraminoplasty and decompression: A case report

Background

Thoracic disc herniation (TDH) is uncommon. Central calcified TDH (CCTDH) is even rare. Traditional open surgery was considered a gold standard to treat CCTDH, but it was accompanied by a high risk of complications. Recently, a technique called percutaneous transforaminal endoscopic decompression (PTED) was adopted to treat TDH. Gu et al. designed a simplified PTED technique and named it percutaneous transforaminal endoscopic surgery (PTES) to treat various types of lumbar disc herniation; it offered the advantages of simple orientation, easy puncture, reduced steps, and little x-ray exposure. However, PTES to treat CCTDH has not been reported in the literature.

Methods

Here, we describe the case of a patient with CCTDH treated with a modified PTES through the unilateral posterolateral approach under local anesthesia and conscious sedation by using a flexible power diamond drill. First, we report that the patient was treated with PTES with later-stage endoscopic foraminoplasty, with an inside-out technique employed at the initial endoscopic decompression stage.

Results

A 50-year-old male with progressive gait disturbance and bilateral leg rigidity with paresis and numbness was diagnosed with CCTDH at the T11/T12 level on MRI and CT examinations. A modified PTES was performed on November 22, 2019. The total mJOA (modified Japanese Orthopedic Association) score preoperatively was 12. The method of the determination of incision and the soft tissue trajectory establishment process were the same as those in the original PTES technique. The foraminoplasty process was divided into initial fluoroscopic and final endoscopic stages. At the fluoroscopic stage, the hand trephine's saw teeth were just rotated into the lateral portion of the ventral bone from the superior articular process (SAP) to seize the SAP firmly, while at the endoscopic stage, in order to remove the ventral bone from the SAP safely under direct endoscopic visualization, adequate foramen enlargement was achieved without causing any risk of damage to the neural structures in the spinal canal. During the endoscopic decompression process, the soft disc fragments ventral to the calcified shell were undermined to form a cavity using an inside-out technique. Then, a flexible endoscopic diamond burr was introduced to degrade the calcified shell, and a curved dissector or a flexible radiofrequency probe was used to dissect the thin bony shell from the dural sac. Eventually, the shell was fractured within the cavity piece by piece to remove the whole CCTDH and achieve adequate dural sac decompression, resulting in minimal blood loss and no complications. The symptoms were gradually alleviated and the patient almost completely recovered at the 3-month follow-up, with no symptom recurrence found at the 2-year follow-up. The mJOA score improved to 17 at the 3-month follow-up and to 18 at the 2-year follow-up compared with 12 points preoperatively.

Conclusions

A modified PTES may be an alternative minimally invasive technique for the treatment of CCTDH and provide similar or better outcomes over traditional open surgery. However, this procedure requires good endoscopic experience on the part of the surgeon and is beset with technical challenges and therefore should be performed with utmost care.

Uniportal, Transforaminal Endoscopic Thoracic Discectomy: Review and Technical Note

Symptomatic thoracic disc herniations are a rare entity and their operative treatment is challenging. Open approaches, despite providing excellent access, are associated with significant access morbidity from thoracotomy, and this has led to an increased interest in minimally invasive techniques such as mini-open approach, thoracoscopic approach and the endoscopic approach. In this article, we describe the technical points for performing a transforaminal endoscopic thoracic discectomy and summarize its literature outcomes in the context of other minimally invasive approaches.

Comparative Analysis of Transforaminal Endoscopic Thoracic Discectomy and Microscopic Discectomy for Symptomatic Thoracic Disc Herniation

OBJECTIVE

To evaluate the clinical outcomes of transforaminal endoscopic thoracic discectomy (TETD) and microscopic discectomy (MD) for the treatment of symptomatic thoracic disc herniation (TDH).

METHODS

Seventy-seven patients (mean, 55.9 years; follow-up, 11.2 months) with symptomatic TDH were retrospectively reviewed (39 TETD and 38 MD). Radiological factors and perioperative outcomes were reviewed. Visual analogue scale (VAS), Oswestry Disability Index (ODI), and American Spinal Injury Association impairment scale were used to evaluate clinical and functional outcomes. Patient satisfaction was evaluated using modified MacNab criteria.

RESULTS

The levels of surgery and the location of hernia were evenly distributed in the both groups. The operative time (70.6 minutes vs. 175.7 minutes), estimated blood loss (3.8 mL vs. 357.4 mL), and length of hospital stay (7.0 days vs. 13.0 days) were significantly different between the TETD and MD groups (p < 0.05). VAS scores for dorsal back pain and ODI scores were significantly improved in both groups (p < 0.05). Patients who underwent TETD tended to be more satisfied with the outcome in terms of the modified MacNab criteria (89.7% vs. 73.0%, p = 0.059). Two patients in the MD group underwent revision surgery, whereas one patient in the TETD group underwent MD because of incomplete decompression.

CONCLUSION

TETD for the symptomatic TDH is a feasible and safe procedure that could be used for a wider range of surgical levels with a shorter operative time and hospital stay and less blood loss. While achieving similar outcomes, TETD achieved better patient satisfaction because of the use of local anesthesia and its minimal invasiveness.

Full Endoscopic Surgery for Thoracic Pathology: Next Step after Mastering Lumbar and Cervical Endoscopic Spine Surgery?

Thoracic disc herniation and stenosis are relatively rare, and various symptoms make them difficult to diagnose. Due to the complexity of neural and vascular structure, surgical treatment of thoracic pathology is challenging. Endoscopic spine surgery is an emerging minimally invasive surgical option. Based on wide experience on the cervical and lumbar spine, an endoscopic approach for the thoracic pathology can be performed beyond the learning curve. Transforaminal approach for thoracic disc herniation, endoscopic unilateral approach, and bilateral decompression for thoracic stenosis have been reported as favorable and safe surgical options. In the present study, the authors described the detailed surgical procedure as well as tips and tricks.

Full Endoscopic Thoracic Discectomy: Is the Interlaminar Approach an Alternative to the Transforaminal Approach? A Technical Note

BACKGROUND

Various approaches are used for decompressive surgeries in the thoracic spine depending on the location and consistency of the pathology, always avoiding manipulation of the thoracic spinal cord. Recently, there has been an effort to achieve adequate results and reduce morbidity with minimally invasive surgeries. Good outcomes and the advantages of full endoscopic spine surgery (FESS) have been proven for surgerical correction of herniated discs and stenoses in the lumbar and cervical spine. Similar evidence has recently been described for the thoracic spine, but it has not previously been reported in Brazil. Although the transforaminal approach is already established for the thoracic spine, the newly described interlaminar approach is equally efficient, and both techniques must be considered when treating thoracic spine diseases. The objective of the present article was to present the full endoscopic interlaminar and transforaminal techniques in patients with symptomatic disc herniation of the thoracic spine, discuss the rationality for implementing FESS in thoracic spine, and discuss the rationality in choosing between both approaches.

METHODS

Two patients were submitted to thoracic FESS. A transforaminal approach was chosen for a T10-T11 foraminal disc herniation; an interlaminar approach was selected for a paramedian T7-T8 disc extrusion. Data regarding operating time, intraoperative images, hospital stay, visual analog scales before and after FESS, course of recovery, and surgery satisfaction were evaluated.

RESULTS

The patients had eventless surgeries, improved from preoperative pain without morbidity. Both were satisfied and recovered well. Hospital stay was less than 6 hours after surgery.

CONCLUSIONS

Transforaminal and interlaminar FESS for thoracic disc herniation are safe, efficient, and minimally invasive alternatives.

CLINICAL RELEVANCE

Despite being an innovative technique with evident advantages, it should be carefully considered along with conventional technique for the treatment of thoracic spine diseases, since its clinical relevance is yet to be determined.

LEVEL OF EVIDENCE: 4

T3-T4 Disc Herniations: Clinical Presentation, Imaging, and Transaxillary Approach

OBJECTIVE

To describe a cohort of T3-T4 thoracic disc herniations (TDHs), their clinical and radiologic characteristics, and unique thoracoscopic transaxillary approach (TAA).

METHODS

All patients operated on for a T3-T4 TDH with minimal follow-up of 1 year were selected.

RESULTS

Eight TAA procedures (6 males and 2 females) were included (1.4%). Six patients reported axial pain, irradiating in 2, 4 sensory changes, 1 objective and 1 merely subjective motor weakness. Only 1 TDH was calcified, none was giant, 2 were accompanied by myelomalacia, and 2 by a small segmental syrinx. A cardiothoracic surgeon helped with exposure through a curved axillary incision using anterior cervical and more recently double-ring wound retractors. All patients were operated on using a 10-mm 30° rigid (three-dimensional) high-definition scope. There were no major complications and a good outcome with symptomatic relief in 7 of 8 patients.

CONCLUSIONS

T3-T4 TDHs are infrequent but may be underdiagnosed because they tend to be small and their signs and symptoms may mimic a cervical problem involving the shoulders and even the arms. There may be a male predominance. The TAA is straightforward, safe, efficacious, and well tolerated despite the supposed vulnerability of the upper thoracic spinal cord. Dissection between large crowded subpleural veins characteristic for the upper thoracic spine and ensuring adequate dura decompression when the steep angle may partially obscure the tip of the instruments does require some extra time. Thorough knowledge of the unique anatomy of the upper thorax is mandatory and the assistance of a cardiothoracic surgeon is highly recommended.

Thoracic vertebra interbody fusion surgery with robotic assisted system in a swine model

Minimally invasive procedures have been increasing in spine surgery, and interest in robotic systems has inclined. In this study, we aimed to evaluate feasibility of a robotic-assisted thoracic spine interbody fusion in a swine model. Neurosurgeons performed the surgical procedures with robotic surgery certificates on the Da Vinci Xi Surgical System. Surgical approaches were applied using four ports while the swine was in the left lateral position. The surgical procedure was accomplished in 70 min including positioning and preparation of robotic system (20 min), placement of ports and thoracic dissection and confirmation of level with the C-arm system (10 min), discectomy and cage insertion (15 min), control of cage position via the C-arm system and closure (10 min). This study showed the anterior thoracic approach with robotic surgery is safe and feasible with providing a wide working area and high image quality.

Five-Year Outcomes After Transforaminal Endoscopic Foraminotomy and Discectomy for Soft and Calcified Thoracic Disc Herniations

BACKGROUND

The aim of this study was to evaluate the safety and long-term clinical outcomes of transforaminal full endoscopic discectomy and foraminotomy performed with manual reamers under local anesthesia on soft and calcified herniated discs in the mid and lower thoracic spine.

METHODS

Postoperative pain relief was self-evaluated by 16 patients using a visual analog scale (VAS) and Oswestry Disability Index (ODI). Patients were scored at 6, 12, 24, and 60 months after surgery.

RESULTS

Significant pain reduction of more than 50% in the VAS score was achieved in 15 out of 16 patients at all review points throughout this study. Similarly, a decrease of more than 50% in ODI scores was achieved in 15 out of 16 patients in all 4 review points. There were no surgical complications. Good postoperative results were achieved in patients regardless of the consistency of the disc herniation.

CONCLUSIONS

Transforaminal full endoscopic discectomy and foraminotomy with manual reamers performed under local anesthesia produces sustained reduction in pain and improves functionality in patients with mid and lower thoracic spine soft and calcified disc herniations. The surgery is safe and straightforward to perform with the correct training.

LEVEL OF EVIDENCE

4.

CLINICAL RELEVANCE

Thoracic transforaminal endoscopic discectomy and foraminotomy, performed in TIVA, may be a useful adjunct for treatment of patients with soft and calcified disc herniations in thoracic spine.

Per Pedicel-Ligament Flavum Tunnel Outside-In Foraminoplasty for T10 -T12 Discectomy under a Percutaneous Endoscope

OBJECTIVE

To describe the effectiveness of T₁₀ -T₁₂ discectomy and per pedicel-ligament flavum tunnel outside-in foraminoplasty protocols under percutaneous endoscope.

METHODS

This retrospective study from September 2017 to June 2019 comprised 10 patients (mean age was 64.7 years, with 7 men and 3 women) with symptomatic thoracic disc herniation. Patients who had 12 months of follow-up and no cervical and lumbar spine surgery or trauma during the follow up period were included in the study. Patients underwent surgery at different levels: 3 patients for T₁₀ -T₁₁ and 7 patients for T₁₁ -T₁₂ . Percutaneous endoscopic thoracic discectomy was performed following under-vision foraminoplasty, which was based on lower pedicel-ligament flavum tunnel detection. Patients who presented with symptomatic soft disc herniation of the thoracic spine and did not respond to conservative treatments were included. Patients with calcified disc herniation or concomitant ossification of the posterior longitudinal ligament were excluded. The surgery involves four steps: (i) facet joint reaching procedures; (ii) sliding the working sleeve caudally to attach the pedicel, rotating the scope to detect the lower border of the superior articular process, the pedicel, and the lower pedicel-ligamentum flavum tunnel (PEFT) under vision, respectively; (iii) milling the superior articular process under vision; and (iv) finding and removing the disc protrusion after the posterior longitudinal ligament is resected. Patient outcomes were evaluated using vision analog scale scores, Oswestry disability index scores, and Japanese Orthopaedic Association scores. The VAS scores, Oswestry disability index scores, and Japanese Orthopaedic Association scores before and after the operation were compared by t-test for statistical analysis. MRI, CT, and plain X-rays were performed in of all the patients before and after surgery.

RESULTS

The patient was usually able to stand and walk approximately 2 h after the surgery. During the 12-month follow-up, all patients showed a significant improvement in pain. Postoperative thoracic MRI examination of all patients showed full decompression of the spinal cord and no residual pressure. Postoperative back pain and nerve root pain were significantly alleviated in all patients, and spinal cord function was significantly restored. The mean visual analog scale scores of patients postoperation were significantly better than those of patients preoperation (6.10 ± 1.37 vs 1.80 ± 0.79, P < 0.05). The mean ODI scores of patients postoperation were better than those of patients preoperation (13% ± 2.36% vs 55% ± 9.20%, P < 0.05). The mean JOA scores increased from 3.2 ± 0.75 to 9.3 ± 0.64. The JOA improvement rate was 79.6% ± 5.1%. There was 1 patient who had transient intercostal neuralgia.

CONCLUSION

Following pedicel-ligament flavum tunnel outside-in foraminoplasty protocols, T₁₀ -T₁₂ discectomy is relatively safe when conducted under percutaneous endoscope.

Full endoscopic surgery for thoracic pathology: an assessment of supportive evidence

In the last five years, surgeons have applied endoscopic transforaminal surgical techniques mastered in the lumbar spine to the treatment of thoracic pathology.

The aim of this systematic review was to collate the available literature to determine the place and efficacy of full endoscopic approaches used in the treatment of thoracic disc prolapse and stenosis.

An electronic literature search of PubMed, Embase, the Cochrane database and Google Scholar was performed as suggested by the Preferred Reporting Items for Systematic Review and Meta-analysis statements. Included were any full-text articles referring to full endoscopic thoracic surgical procedures in any language.

We identified 17 patient series, one cohort study and 13 case reports with single or of up to three patients.

Although the majority included disc pathology, 11 papers related cord compression in a proportion of cases to ossification of the ligamentum flavum or posterior longitudinal ligament. Two studies described the treatment of discitis and one reported the use of endoscopy for tumour resection.

Where reported, excellent or good outcomes were achieved for full endoscopic procedures in a mean of 81% of patients (range 46–100%) with a complication rate of 8% (range 0–15%), comparing favourably with rates reported after open discectomy (anterior, posterolateral and thoracoscopic) or by endoscopic tubular assisted approaches. Twenty-one of the 31 author groups reported use of local anaesthesia plus sedation rather than general anaesthesia, providing ‘self-neuromonitoring’ by allowing patients to respond to cord and/or nerve stimuli.

Cite this article: EFORT Open Rev 2021;6:50-60. DOI: 10.1302/2058-5241.6.200080

Transforaminal Endoscopic Discectomy for Large, Two Level Calcified, Thoracic Disc Herniations With 5-Year Follow-up

To describe technical details and benefits of transforaminal endoscopic discectomy for treatment of patients with large, dorsomedial, calcified thoracic disc herniations at 2 levels and to report on their clinical outcomes in long follow-up period of 5 years using 4 different outcome tools. We present 2 patients with large, calcified disc herniations at 2 levels in mid and lower thoracic spine treated endoscopically in local anesthesia. Clinical outcomes were analyzed using verbal numeric scale (VNS), Roland-Morris low back pain and disability questionnaire (RMQ), Oswestry Disability Index (ODI), and modified MacNab criteria at 6-, 12-, 24-, 60-month follow-up. After transforaminal endoscopic discectomy, both patients had significant postoperative reduction of back pain using VNS and significant outcome improvement using ODI, RMQ score, and modified MacNab criteria. These results did not change during all 4 follow-up periods. Transforaminal percutaneous full-endoscopic discectomy and hand reamers foraminotomy in local anesthesia is feasible and effective surgical technique for patients with large, calcified thoracic disc herniations at 2 levels even in long follow-up period of 5 years using 4 different outcome measuring tools. All 3 outcome measuring tools correlated well with pain reduction using VNS.

Thoracic Endoscopic Spine Surgery: A Comprehensive Review

BACKGROUND

From the 1990s, there has been growth in the literature demonstrating the feasibility of minimally invasive approaches for treating diverse spinal disorders. There is still much work to be done in circumnavigating the technical challenges and elucidating relative advantages of endoscopic techniques in spine surgery. In this comprehensive literature review, we discuss the history, advantages, disadvantages, approaches, and technology of, and critically examine peer-reviewed studies specifically addressing, endoscopic thoracic spinal surgery.

METHODS

Literature review was conducted with the key words "endoscopic," "minimally invasive," and "thoracic spinal surgery," using PubMed, Web of Science, and Google Scholar.

RESULTS

Review of 241 thorascopic procedures showed a success rate of 98% to 100%, low morbidity, and favorable complication profile. Review of 115 thoracic fixation procedures demonstrated high success rate, and 87% of screw positions were rated "good." Review of 55 full endoscopic uniportal decompressions showed sufficient decompression in most patients. Match pair analysis of 34 patients comparing video-assisted thoracoscopy surgery (VATS) or posterior spinal fusion reported the VATS group had increased operative duration but reduced blood loss.

CONCLUSIONS

Based on our literature review, there is a high rate of positive outcomes with endoscopic thoracic spine surgery, which reduces tissue dissection, intraoperative blood loss, and epidural fibrosis. However, the technical challenge highlights the importance of further training and innovation in this rapidly evolving field.

LEVEL OF EVIDENCE

3.

CLINICAL RELEVANCE

There is growing evidence demonstrating the success of endoscopic thoracic spinal surgery. Populations that could be helped include the elderly and immunocompromised, who would benefit from decreased hospital stay and enhanced recovery time.

Current and Future of Endoscopic Spine Surgery: What are the Common Procedures we Have Now and What Lies Ahead?

The aging population around the world leads to increasing incidence of degenerative spinal conditions. There is a need for a minimally invasive technique in treatment for spinal conditions to meet the medical complexity and comorbidities that comes with aging. Principles of endoscopy are similar to minimally invasive surgery, which is to decrease pressure on soft tissue crushing from prolonged retraction, avoid soft tissue stripping and dissection, and bone and ligamentous preservation for optimal decompression without excessive destruction. Endoscopic spine surgery techniques started slowly in development in the 1970s to 2000s, with a rapid phase of development since the turn of the 21st century with endoscopic solutions developing in cervical, thoracic, and lumbar conditions with increasing complexity in nature of operation. Technological enhancement with progressively supportive literature is pushing boundaries of endoscopy from the early days of soft tissue procedure to current fusion procedures, endoscopic spine surgery techniques is covering more areas of spine than ever previously possible with good clinical results. We present a review on the current techniques available and postulated near future development for endoscopic spine surgery.

Transforaminal Endoscopic Thoracic Discectomy: Technical Review to Prevent Complications

For all the spine surgeons, thoracic disc herniations (TDHs) entrust a real challenge in terms of patient diagnosis, proper selection, surgical technique, and potential adverse events. TDHs are relatively uncommon compared to the lumbar and cervical levels. Literature reports a variable prevalence of TDHs around 6% to 40%, but less than 1% of all disk herniations are symptomatic TDHs, evidencing as a relatively unusual condition. Nowadays, transforaminal endoscopic thoracic discectomy (TETD) has been implemented as an alternative to classic open procedures with results that are as good as and, in some situations, better than those in traditional discectomy. However, the surgeon must be familiar with endoscopic lumbar spine surgery before opting to perform a TETD, considering that the learning curve is much harder. We describe all the steps and safety considerations during TETD based on the anatomic differences compared to lumbar endoscopic procedures. TETD is an effective and safe method that yields more benefits, provides a direct route to the lesion with less morbidity, and is performed in a minimally invasive way. Many severe complications related to the thoracic region could be avoided having the proper knowledge, adequate technique, and safety routes and considerations.

Transforaminal Endoscopic Discectomy for Hard or Calcified Lumbar Disc Herniation: A New Surgical Technique and Clinical Outcomes

OBJECTIVE

Hard or calcified discs are often adherent to surrounding nerve tissue. The whole herniated disc is difficult to remove by pulling part of the hernia mass, which makes obtaining good results through endoscopic treatment difficult. The purpose of this study was to describe the details of the transforaminal endoscopic lumbar discectomy technique for a hard or calcified disc and report the clinical results.

METHODS

From October 2016 to June 2019, 43 consecutive cases diagnosed as hard or calcified lumbar disc herniation at our institution and treated with transforaminal endoscopic discectomy were evaluated. Endoscopic decompression was performed in patients with hard or calcified lumbar disc herniation.

RESULTS

The preoperative visual analog scale score for leg pain (mean ± standard deviation) was 7.09 ± 1.74. The score improved to 2.55 ± 1.35 at 1 week postoperatively, 1.88 ± 1.29 at 4 weeks postoperatively, and 1.58 ± 1.0 at 26 weeks postoperatively (P < 0.01 for all). The preoperative Oswestry Disability Index (mean ± standard deviation) was 55.4 ± 23.04, which improved to 30.89 ± 13.64 at 1 week postoperatively, 23.08 ± 11.64 at 4 weeks postoperatively, and 16.42 ± 9.76 at 26 weeks postoperatively (P < 0.01 for all). Two patients developed a dural laceration. Both patients were discharged after several hours of observation. None of the patients had postoperative infection, epidural hematoma, or delayed neurological deterioration.

CONCLUSIONS

Transforaminal endoscopic discectomy could be an effective treatment method for a selected group of patients with hard or calcified lumbar disc herniation.

Overview of Minimally Invasive Spine Surgery

Minimally invasive spine surgery (MISS) has continued to evolve over the past few decades, with significant advancements in technology and technical skills. From endonasal cervical approaches to extreme lateral lumbar interbody fusions, MISS has showcased its usefulness across all practice areas of the spine, with unique points of access to avoid pertinent neurovascular structures. Adult spine deformity has also recognized the importance of minimally invasive techniques in its ability to limit complications and to provide adequate sagittal alignment correction and improvements in patients' functional status. Although MISS has continued to make significant progress clinically, consideration must also be given to its economic impact and the learning curve surgeons experience in adding these procedures to their armamentarium. This review examines current innovations in MISS, as well as the economic impact and future directions of the field.

Transforaminal endoscopic thoracic discectomy with foraminoplasty for the treatment of thoracic disc herniation

Background

Symptomatic thoracic disc herniation (TDH) is a rare clinical entity and surgical intervention for it is even more uncommon. Despite several surgical techniques being described for thoracic discectomy, considering the unique surgical challenges, none of them have been accepted universally. Minimally invasive techniques have brought in a paradigm shift in the management of cervical/lumbar spinal disorders and similar techniques have been extrapolated to the thoracic region too. The purpose of this paper is to describe our technique, surgical experience, and the clinical results of transforaminal endoscopic thoracic discectomy (TETD).

Methods

Consecutive patients who underwent TETD (2001-2018) were reviewed. Patients who had a minimum of 6 months of follow-up, and without cervical and lumbar spine surgery or trauma during the follow-up period were included in the study. TETD was performed in patients who presented with symptomatic disc herniation of the thoracic spine and did not respond to conservative treatments. Patients with calcified disc herniation or concomitant ossification of the posterior longitudinal ligament (OPLL) were excluded. Under local anesthesia and intravenous sedation, a 4.7-mm endoscope (TESSYS, Joimax GmbH, Germany) was introduced via transforaminal approach with foraminoplasty using reamer. Patient outcome was evaluated using visual analogue scale (VAS) and Oswestry disability index (ODI) scores. Patient satisfaction was measured using Macnab's criteria.

Results

Ninety-two consecutive patients (mean age was 48.9 years, 57 males) who underwent TETD from 2001 to 2018 met the inclusion criteria. Patients underwent surgery at different levels: 16 patients for T2-3 to T5-6 level, 41 cases for T6-7 to T8-9, and 35 patients for T9-10 to T12-L1. During follow-up for an average of 38.4 months, all patients showed a significant improvement of pain (7.6 to 1.6 in VAS and 68.2 vs. 13.2 for ODI, P<0.05 for both). There was one patient who had transient motor weakness.

Conclusions

TETD for soft, paramedian or lateral symptomatic TDH is a feasible and effective minimally invasive treatment option with favorable clinical results.