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.

Posterior video-assisted trans pedicular surgery for calcified midline thoracic disc herniation

BACKGROUND

In the treatment of patients with calcified midline thoracic disc herniation (CMTDH), the posterior video-assisted transpedicular surgery (VATPS) technique is employed. Both anterior and posterior surgical approaches for treating CMTDH carry a significant risk of surgical complications and potential morbidity. This technical note introduces a surgical procedure that avoids the drawbacks associated with these approaches.

METHODS

The VATPS technique presents a comprehensive approach for treating thoracic disc herniation, combining both microscopic and endoscopic stages. The microscopic phase entails a small thoracoscopic incision, muscle release, hemilaminotomy, facet joint resection, and vertebra removal, culminating in creating a corpectomy cavity for endoscope access. Careful separation of adhesions between the dura and ligaments marks this stage. Transitioning to the endoscopic phase, an endoscope is inserted into the cavity, allowing for precise visualization and separation of residual adhesions, removal of calcified disc fragments using specialized instruments, and ensuring complete discectomy.

RESULTS

Fourteen patients underwent VATPS for CMTDH. During the procedure, evoked responses were reduced in one patient. However, no postoperative neurological deficits were observed. We also noted significant improvements in the Oswestry Disability Index (ODI) and the Visual Analog Scale (VAS) scores when comparing the preoperative and postoperative assessments.

CONCLUSION

VATPS, a minimally invasive technique, offers excellent anterior visibility comparable to that of the anterolateral approach, all while avoiding the adverse effects associated with thoracotomies and the complications resulting from spinal cord encroachment often seen in the posterolateral approach. Moreover, it is a safer alternative to conventional endoscopic posterior thoracic surgery. The cavity formed within the vertebral corpus provides ample working space for the use of an endoscope.

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.

Full-endoscopic anterior excision of thoracic disc herniations, including giant and calcified discs with spinal cord compression: surgical technique and outcomes

PURPOSE

Operations on thoracic herniated discs are comparatively rare and often demanding. An individual approach and mastery of different surgical techniques and surgical approaches are necessary. The main factors for the chosen surgical technique and approach are the anatomical localization, consistency of the pathology, the general condition of the patient and the experience of the surgeon. The purpose of this study was to evaluate the technical possibilities and outcomes of the full-endoscopic technique with interlaminar, extraforaminal and transthoracic retropleural approaches in patients with symptomatic herniated discs with anterior neural compression.

METHODS

In 49 patients with thoracic disc herniations, decompression was performed between 2016 and 2020, using a full-endoscopic interlaminar, extraforaminal or transthoracic retropleural approach. Clinical data and imaging were collected during follow-up of 18 months.

RESULTS

Sufficient decompression was achieved in all cases with the full-endoscopic surgical technique. Two patients experienced worsening of myelopathy, one of which was of transient duration, and one patient required reoperation for an epidural hematoma. No other complications were recorded. All other patients experienced a regression or improvement of symptoms.

CONCLUSION

The full-endoscopic technique with interlaminar, extraforaminal or transthoracic retropleural approach is a sufficient and minimally invasive method. All three full-endoscopic approaches of the thoracic spine are required to enable sufficient decompression of the anterior pathologies examined here.

Evaluation of clinical outcomes, complication rate, feasibility, and applicability of transfacet pedicle-sparing approach in thoracic disc herniation: a systematic review and meta-analysis

OBJECTIVE

This study aimed to evaluate the clinical outcomes, complication rate, feasibility, and applicability of transfacet pedicle-sparing approach for treating thoracic disc herniation.

METHODS

We searched three databases including the Cochrane Library, PubMed, and Embase for eligible studies until Dec 2022. The quality of studies and their risk of bias were assessed using the methodological index for non-randomized studies. We evaluated the heterogeneity between studies using the I² statistic and the P-value for the heterogeneity.

RESULTS

A total of 328 patients described in 11 included articles were published from 2009 to 2022. Pain outcomes using the visual analog scale (VAS score) were reported in four studies. The standardized mean difference was reported as 0.749 (CI 95% 0.555-0.943). The obtained result showed the positive effect of the procedure and the improvement of patients' pain after the surgery. Myelopathy outcomes using the Nurick score were reported in five studies. The standardized mean difference was reported as 0.775 (CI 95% 0.479-1.071). The result showed the positive effect of the procedure. Eight studies assessed postoperative complications and neurological deterioration. The pooled overall complication was 12.4% (32/258) and 3.5% (9/258) neurological worsening.

CONCLUSION

The results of this study demonstrated a positive effect of the transfacet pedicle-sparing approach on the clinical outcomes of patients with thoracic disc herniation surgery. The technique has been shown to be safe and effective for the right patient. The technique is associated with lower rates of complications and a shorter hospital stay compared to other surgical approaches. This information can assist clinicians in making informed decisions when selecting the most appropriate surgical technique for their patients with thoracic disc herniation.

Monoradiculopathy-induced abdominal pseudohernia caused by T11-12 soft disc herniation: a case report and literature review

BACKGROUND

An abdominal pseudohernia is a rare clinical entity that consists of an abnormal bulging of the abdominal wall that can resemble a true hernia but does not have an associated underlying fascial or muscle defect. Abdominal pseudohernia is believed to result from denervation of the abdominal muscles in cases of herpes zoster infection, diabetes mellitus, lower thoracic or upper lumbar disc herniation, surgical injuries, and rib fracture. To date, nine cases of abdominal pseudohernia caused by disc herniation at the lower thoracic or upper lumbar levels have been reported.

CASE PRESENTATION

A 35-year-old man with no underlying disease or traumatic event presented with chief complaints of left flank pain and a protruding left lower abdominal mass that had formed one day earlier. There was no true abdominal hernia on abdominal computed tomography (CT), although CT and magnetic resonance imaging (MRI) showed a herniated soft (non-calcified) disc into the left neural foramen at the T11-12 level. A nonsteroidal anti-inflammatory drug was prescribed for the flank pain, and the patient was followed on a regular basis for six months. Follow-up MRI taken at the last visit showed complete resorption of the herniated disc. Abdominal pseudohernia and flank pain were also completely resolved.

CONCLUSION

We report a rare case of monoradiculopathy-induced abdominal pseudohernia caused by foraminal soft disc herniation at the T11-12 level. In patients who have an abdominal pseudohernia without herpes zoster infection, diabetes mellitus, or traumatic events, lower thoracic disc herniations should be included in differential diagnosis.

A minimally invasive tubular retractor-assisted retropleural approach for thoracic disc herniations - case series and technical note

PURPOSE

Thoracic disc herniations are uncommon and carry a high risk for neurological deterioration. Traditional surgical approaches include thoracotomy, costotransversectomy or posterior approaches with considerable morbidity. In this technical note with case series, we describe a minimally invasive tubular retractor-assisted retropleural approach for simple and less invasive microsurgical exploration of thoracic disc herniations from a lateral angle.

METHODS

Surgical technique consisted of partial rib resection and retropleural dissection followed by the placement of a tubular retractor (METRx Tubes, Medtronic) for an anterior-lateral exposure of the disc and neuroforamen. Epidemiological, clinical and surgical patient data were acquired.

RESULTS

Between 2017 and 2020, six patients were surgically treated using the minimally invasive tubular retractor-assisted retropleural approach. Microsurgical exposure of the disc and neural structures was achieved from a lateral direction without requiring thoracotomy or lung deflation. Control imaging confirmed resection in all cases without relevant residuum. As postoperative complications, one dural injury and one postoperative pneumothorax occured. No neurologic deterioration or recurrence occurred during a median follow-up of 3 months.

CONCLUSION

The described tubular retractor-assisted retropleural exposure serves as a feasible minimally invasive microsurgical approach to the anterior-lateral thoracic spine.

A challenging recurrent thoracic disc herniation

Background

Thoracic disc herniations are rare and occur at the rate of 1/1,000,000/year. Surgical approach must be individually tailored to the size, location, and consistency of the herniated disc. Notably, here, we report the unusual recurrence of a thoracic herniated disc.

Case Description

In 2014, a 53-year-old female presented with thoracic back pain, and paraparesis, attributed to an magnetic resonance imaging/computed tomography (CT)-documented left paramedian T8-T9 calcific disc herniation. She underwent a left hemilaminectomy/costotrasversectomy following which she experienced complete regression of her symptoms. Notably, the postoperative radiological studies at that time demonstrated some residual although asymptomatic calcific disc herniation. Eight years later, she again presented, but now with the chief complaint of difficulty breathing. The new CT scan showed a new calcified herniated disc fragment superimposed on the previously documented residual disc. Through a posterolateral transfacet approach, she underwent resection of the disc complex. An intraoperative CT scan confirmed complete removal of the recurrent calcified disc herniation. Following the second surgery, the patient fully recovered and remains asymptomatic.

Conclusion

A 53-year-old female first presented with a left-sided T8/T9 thoracic calcified disc herniation that was initially partially resected). When another larger fragment appeared 8 years later, superimposed on the previously documented residual disc, it was successfully removed through a posterolateral transfacet approach completed with CT guidance and neuronavigation.

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.

Thoracoscopic Microdiscectomy with Preservation of Rib and Costovertebral Joint

INTRODUCTION

Thoracic disc herniations (TDH) may cause major morbidity. While thoracoscopic microdiscectomy (TMD) is an excellent technique, postoperative band-like pain is an important drawback.

MATERIAL AND METHODS

We performed 181 consecutive TMDs (including 39 high-risk cases) with preservation of rib and costovertebral joint (CVJ). We shave a few mm of the rib, drill straight to target, and avoid opening the canal before the TDH is completely free and (in case of giant TDHs) internally debulked, creating initial decompression and limiting epidural venous oozing. Subsequently, we gently mobilize and remove the residual TDH while avoiding leverage.

RESULTS

Skin-to-skin time was <90' in 64, 90-120' in 48, >120' in 20, unknown in 10, and 162' mean in 39 high-risk procedures. Blood loss was <100 mL in 76, <250 mL in 48, and 537 mL mean in 39 high-risk procedures. The technique was successfully applied in all (including nine dural repairs) without a single conversion. We observed an increased neurological deficit in two (1.1%) and inadequate decompression in merely one (wrong level). Complications (mainly pulmonary) were few and managed conservatively, except for a segmental artery pseudoaneurysm treated endovascularly. We observed a substantial decrease in acute and chronic postoperative pain.

DISCUSSION

The technique is fast, straightforward, minimizes bone resection and blood loss, improves orientation, safely and effectively deals with any TDH, and prevents postoperative band-like pain as the CVJ is preserved.

CONCLUSION

We hope this technique will find broader acceptance among a new generation of spine surgeons to benefit patients suffering TDH-related myelopathy or merely intractable pain.

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.

Posterior-only approach for the treatment of symptomatic central thoracic disc herniation regardless of calcification: A consecutive case series of 30 cases over five years

PURPOSE

To report the safety and efficacy of posterolateral approach for thoracic disc herniation (TDH) via a consecutive clinical case series of 30 central thoracic disc herniations that were all operated through a posterolateral approach.

METHODS

A retrospective review was conducted of all patients with symptomatic TDH who underwent surgical intervention from 2016 to 2021. A total of 23 patients comprising 30 central TDH were included in the study. Age, gender, location of the lesion, preoperative and post-operative Frankel and Nurick scores, surgical approach and instrumented vertebrae, and length of stay were recorded.

FINDINGS

23 patients with an average age of 62 were included in the study. 30 of the 32 symptomatic TDH were centrally located. 8/32 TDH were calcified while 24/32 TDH were non-calcified. Unilateral and bilateral transpedicular approach was used in the treatment of 12/32 and 10/32 disc herniations respectively. A transfacet-pedicle sparing approach was used in 10/32 disc herniations. 19/23 (82.6%) of the patients had improvement in Nurick score while 12/23 (52.2%) patients had improvement in their Frankel scores. The average length of stay was 4.5 days. No major complications were encountered. All patients underwent a short-segment instrumented construct with no need for revision surgery for thoracic disc herniation, worsening myelopathy, or instrumentation failure.

CONCLUSIONS

83% of the patients who underwent a transfacet or transpedicular decompression for the treatment of symptomatic TDH had improvement in their myelopathy with no neurological deterioration in any of the patients. Given the familiarity and low morbidity associated with a transfacet or transpedicular approach, posterolateral-based approaches remains an excellent alternative for surgical management of majority of the patients with thoracic disc herniations.

Transdural Spinal Cord Herniation: An Exceptional Complication of Thoracoscopic Discectomy: 2-Dimensional Operative Video

Thoracic disc herniation is a rare and severe condition, whose treatment may have complications including dural tears. Although benign in most cases, dural tears may induce iatrogenic transdural herniation of the spinal cord. The video demonstrates the diagnosis and surgical treatment of iatrogenic transdural herniation of the spinal cord. Here, we report a case of spinal cord herniation after thorascopic treatment of a thoracic disc herniation (DH). A 28-yr-old male presented with several years of left lower extremity weakness and was found to have a T6-7 DH. He underwent DH resection through video assisted mini-thoracotomy at another institution. In the immediate postoperative period, he developed a Brown-Sequard syndrome with left leg weakness. The surgeon decided not to reoperate and the patient improved with rehabilitation, allowing him to walk again. At 6 mo postop, he experienced sudden neurologic worsening but did not present to our clinic until 6 mo later. At this time, he had near complete paraplegia with bilateral lower extremity spasticity and central neuropathic pain. MRI showed a pseudo-meningocele and features suggesting a lateral spinal cord herniation. After a multidisciplinary meeting, we elected to perform a posterolateral approach with costo-arthro-pediculectomy and durotomy to repair the SC herniation. Immediately postop, the patient had a slight improvement in right lower extremity function, with decreased pain and spasticity. This case shows a transdural SC herniation, a rare complication after resection of DH. It is possible that an unreported or unrecognized dural tear at the time of the initial surgery, combined with the negative pressure of the thoracic cavity, put the patient at risk for this particular complication. The authors state that the patient gave his informed consent.

Management of single-level thoracic disc herniation through a modified transfacet approach: A review of 86 patients

Background:

Symptomatic thoracic disc herniation (TDH) is rare and does not typically resolve with conservative management. Traditional surgical management is the transthoracic approach; however, this approach can carry significant risk. Posterolateral approaches are less invasive, but no single approach has proven to be more effective than the other results are often dependent on surgeon experience with a particular approach, as well as the location and characteristics of the disc herniation.

Methods:

This was retrospective review of a prospectively collected database. Eighty-six patients with TDH treated surgically through the modified transfacet approach were reviewed and evaluated for pain improvement, Nurick grade, and neurological symptoms. Patients were followed for 12 months postoperatively; estimated blood loss, length of hospital stay, hospital course, and postoperative complications were also assessed.

Results:

All attempts at disc resection were successful. Most patients reported improvement in pain, sensory involvement, and strength. Seventy-nine patients had complete resolution of their symptoms while four patients had unchanged symptoms. Three patients experienced mild neurologic worsening postoperatively, but this resolved back to baseline. One patient experienced myelopathy during the postoperative period that resolved with steroid administration. The procedure was well tolerated with minimal complications.

Conclusion:

TDH can be managed surgically through a variety of approaches. The selection of approach is dependent on surgeon experience with an approach, the patient’s health, and the location and type of disc. The transfacet approach is safe and efficacious.

A rare case of giant calcified thoracic disc herniation, OPLL and OLF: how I do it

BACKGROUND

Thoracic myelopathy can have different aetiologies. Based on the location and on the nature of spinal cord compression, different surgical approaches may be indicated.

METHOD

We present a rare case of thoracic myelopathy caused by the coexistence of a giant disc herniation, OPLL and OLF, and we describe the surgical approach, with a focus on technical nuances and strategies to avoid complications.

CONCLUSION

Careful presurgical planning and microsurgery are fundamental in achieving a satisfactory spinal cord decompression. IONM, endoscopy-assisted microsurgery and intraoperative navigation can enhance the safety of surgery and the extent of safe surgical decompression.

Outcome and negative events in thoracic disc herniation surgery: a Danish registry study

BACKGROUND

Thoracic disc herniation (TDH) is a surgically demanding entity. Various surgical approaches have been developed and advanced in an attempt to achieve sufficient outcomes and reduce consecutive complication rates. Still, controversy exists regarding selecting the best surgical approach. This retrospective study aims to support decision-making regarding surgical approach.

METHODS

We performed a retrospective analysis of 71 patients who underwent thoracic discectomy at Aarhus University Hospital, Denmark, between 1996 and 2015. Patients were divided into two groups depending on whether a lateral approach or a posterior approach was used. Data on demographics, symptomatology, peri- and post-operative events, length of hospitalization and discharge disposition were assembled from medical records.

RESULTS

Lateral and posterior approach had an approximately equal peri-operative event rate (39% versus 36%), whereas the lateral approach was associated with a higher post-operative event rate in-hospital and post-discharge than the posterior approach (50% versus 18%; 45% versus 40%). The overall probability of improvement in clinical outcome regardless approach at follow-up was 77% in the short-term and 80% in the long-term. Odds of clinical improvement at any time point was 29% higher with the lateral approach than with the posterior approach (OR = 1.29, 95% CI: 0.52-3.21, p = .76). Adjusting for time, the odds of clinical improvement at short-term follow-up was twice as high for the lateral than for the posterior approach (OR = 2.16, 95% CI: 0.16-30.11); however, the trend seems to fade away over time (OR = 1.10, 95% CI: 0.07-17.55).

CONCLUSIONS

The probability of improving after TDH surgery is good. However, a clear conclusion regarding the best surgical approach cannot be established; thus, surgeons should consider pros and cons of each approach when allocating a patient to surgery.

Management of Thoracic Disc Herniation Using the Mini-Open Retropleural Approach: Technique Illustration and Clinical Outcomes of 33 Patients From a Single Academic Center

BACKGROUND

Conventional surgical approaches used in the management of thoracic disc herniation (TDH) are associated with high morbidity. The development of minimally invasive and mini-open approaches has consistently improved patient outcomes.

OBJECTIVE

To report our experience and outcomes of patients with symptomatic TDHs who underwent discectomy and partial corpectomy using the mini-open retropleural (MORP) approach as well as provide a detailed and illustrated technical description of the approach.

METHODS

Retrospective chart review was performed on all patients with symptomatic TDHs who underwent a MORP approach at a tertiary academic center between 2011 and 2019. Patient demographic, clinical, and imaging data were examined (n = 33). The surgical technique is illustrated and described in detail.

RESULTS

Discectomy of the herniated thoracic discs was successfully achieved in all patients using the MORP approach. Calcified discs were present in 63.6% (n = 21) of patients. Immediate instrumentation and fusion were performed in 30.3% (n = 10) of patients, which were among the earlier cases in this series. Symptomatic pleural effusions and cerebrospinal fluid leakage occurred in 6.1% (n = 2) and 9.1% (n = 3), respectively. No patient required chest tube placement.

CONCLUSION

The MORP approach described in this manuscript is feasible and safe in achieving discectomy in patients with symptomatic TDHs. Compared to conventional open and other minimally invasive approaches, patients undergoing the MORP approach may have better outcomes with lower complication rates.

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.

Trans-thoracic versus retropleural approach for symptomatic thoracic disc herniations: comparative analysis of 94 consecutive cases

PURPOSE

The authors illustrate their results in the surgical treatment of symptomatic thoracic disc herniations (TDHs) by comparing the traditional open to the less invasive retropleural lateral approaches.

METHODS

Retrospective review of 94 consecutive cases treated at a single Institution between 1988 and 2014. Fifty-two patients were males, 42 females, mean age was 53.9 years. Mean follow-up was 46.9 months (12-79 months). 33 patients were diagnosed with a giant thoracic disc herniation (GTDH). Upon admission, the most common symptoms were: motor impairment (91.4%, n = 86), neuropathic radicular pain with VAS > 4 (50%), bladder and bowel dysfunction (57.4% and 41.4% respectively) and sensory disturbances (29.7%). The surgical approach was based upon level, laterality and presence or absence of calcified lesions.

RESULTS

Decompression was performed in 7 cases via a thoraco-laparo-phrenotomy and in 87 cases via an antero-lateral thoracotomy. Out of the latter cases, 49 (56%) were trans-thoracic trans-pleural approaches (TTA) and 38 (44%) were less invasive retropleural approaches (MIRA). At follow-up, there were 59.5% neurologically intact patients according to the McCormick Scale, while 64.8% and 67% had no bladder or bowel dysfunction respectively. Complications occurred in 24 patients (25.5%). Pulmonary complications were the commonest (12.7%) with pleural effusion being significantly more common in patients treated with TTA compared to MIRA (20% vs 5.2%: X² 4.13 P:0.042). Severe post-operative neuralgia (VAS 7-10) was also significantly more frequent in the TTA group (22.4% vs 2.6% X² 7.07 p 0.0078).

CONCLUSIONS

MIRA is a safe and effective technique to obtain adequate TDH decompression and is associated with lower morbidity compared to TTA.

Differences in clinical and radiological features of thoracic disc herniation presenting with acute progressive myelopathy

PURPOSE

Symptomatic thoracic disc herniation (TDH) is relatively rare, but patients with progressive myelopathy require surgical treatment without delay in diagnosis. The aim of this study was to review clinical and radiological features in patients with TDH presenting with myelopathy.

METHODS

A total of 28 consecutive patients with thoracic myelopathy (Frankel grade C or worse) due to TDH who underwent surgery were divided into 3 groups based on the time for development of myelopathy (acute (< 72 h), subacute (within a few weeks), and chronic [gradually over > 1 month)] and their data were analyzed.

RESULTS

The patients in the acute group were significantly younger and had a higher body mass index (BMI) compared to those in the subacute and chronic groups. Most cases of acute myelopathy were affected in the upper thoracic level, whereas all patients with subacute and chronic myelopathy had lesions in the lower thoracic level below T8-9. Interestingly, the affected thoracic level in patients with acute myelopathy matched the upper line of the sternum. The rate of acquired walking ability without assistance was only 50.0% in the acute group.

CONCLUSIONS

This study suggests that TDH presenting with acute myelopathy may have different clinical and radiological features compared to those of TDH with subacute and chronic myelopathy. Upper TDH should be suspected in cases of acute myelopathy that develops with sudden-onset back pain after certain triggers in younger and higher BMI people. These affected thoracic level matched with the upper line of the sternum in each case.

Anterior spinal artery syndrome caused by thoracic disc herniation

We present a case of a midline thoracic disc herniation causing acute anterior spinal artery (ASA) syndrome successfully managed surgically. A 54-year-old female with no significant past medical history presented with sudden onset severe back pain followed by rapidly evolving paraparesis with urinary and bowel incontinence. Her neurological exam was consistent with ASA syndrome. An MRI revealed T2 signal change in the thoracic spinal cord and midline disc herniation at the level of T8/T9. Spinal angiography revealed an ASA arising the right T11 segmental artery with no flow towards the T8/T9 region. The patient underwent a T8/T9 discectomy with a lateral interbody fusion that resulted in dramatic clinical improvement. A postoperative angiogram confirmed improvement of flow in the ASA. This is the first report of an angiographically confirmed symptomatic ASA syndrome caused by a thoracic disc herniation successfully managed with up-front surgery.

Percutaneous Endoscopic Thoracic Decompression for Thoracic Spinal Stenosis Under Local Anesthesia

BACKGROUND

Thoracic spinal stenosis (TSS), a common vertebral degenerative disease, is generally treated via surgical decompression. Percutaneous endoscopic thoracic decompression (PETD) under local anesthesia is considered a relatively safe, minimally invasive procedure. Few reports detail the success of endoscopic decompression for treatment of TSS caused by ossification of ligamentum flavum, the most common cause of TSS. This study investigated application of PETD for treatment of TSS caused by ossification of ligamentum flavum, ossification of posterior longitudinal ligament, or thoracic disc herniation.

METHODS

From January 2017 to January 2019, 12 consecutive patients (6 men and 6 women) underwent PETD. TSS was caused by ossification of ligamentum flavum in 5 patients, thoracic disc herniation in 5 patients, and ossification of posterior longitudinal ligament in 2 patients. All cases were followed up for 1 year postoperatively. Preoperative and postoperative neurologic status was evaluated using the modified Japanese Orthopaedic Association score, and complications were documented.

RESULTS

Average modified Japanese Orthopaedic Association score improved significantly from 6.25 ± 1.60 preoperatively to 9.75 ± 1.21 at final follow-up. Dural tear was observed in 1 case during the intervention, and 1 case had transient worsening of preoperative paralysis. Recovery at final follow-up was classified as excellent in 5 cases, good in 6 cases, and poor in 1 case.

CONCLUSIONS

This retrospective analysis showed that PETD under local anesthesia may be a feasible alternative to treat TSS in elderly patients with other underlying complications for whom general anesthesia or major surgical trauma would be harmful.

Clinicopathologic Features of Thoracolumbar Interdural Disc Herniations: A Retrospective Case Series with a Systematic Literature Review

BACKGROUND

Transdural disc herniations represent about 0.3% of all herniated discs. Preoperative imaging rarely demonstrates this condition. Therefore, diagnosis of transdural disc herniation is usually made intraoperatively. We describe the clinicopathologic features of extremely rare cases of thoracic and lumbar interdural disc herniations mimicking spinal intradural en plaque tumors.

METHODS

This is a retrospective case series with a systematic literature review. Clinical presentation, imaging, differential diagnosis, intraoperative microsurgical findings, and possible pathogenesis were reviewed according to published guidelines. All patients underwent a posterior approach for microsurgical excision of disc herniation, but no epidural lesion was found. At intradural exploration, a tumor-like en plaque lesion was discovered. The surface of the lesion was incised, and multiple friable, cartilaginous white-yellow fragments were removed to achieve complete intralesional excision.

RESULTS

The postoperative course was characterized by progressive neurologic improvement in all cases. In peculiar anatomic (adhesions between the anulus fibrosus, posterior longitudinal ligament, and ventral surface of dura mater) and pathologic (calcified giant disc herniation, spinal canal stenosis, previous lumbar spine surgery) conditions, penetration of disc fragment in the thickness of spinal dura mater can occur.

CONCLUSIONS

Interdural disc herniations constitute a rare pathologic condition characterized by the migration of the herniated disc in neither the epidural nor the subdural spinal space, but rather in the thickness of the spinal dura mater. Further advances are necessary in neuroradiologic investigations to achieve a correct preoperative diagnosis, which is essential, as spine surgeons must be aware of these rare pathologies.

[Technical notes and clinical efficacy analysis of full-endoscopic thoracic discectomy via transforaminal approach]

Objective: To study the technical notes and clinical efficacy of full-endoscopic thoracic intervertebral discectomy via transforaminal approach. Methods: We included 16 patients with thoracic disc herniation treated by full-endoscopic thoracic discectomy via transforaminal approach between January 2017 and September 2018 in ours department of orthopedics. The average age is 53.7 years. The compressionare classified by nature: 5 cases of soft thoracic disc herniation, 7 cases of calcified or ossified thoracic disc herniation, and 4 cases of osteophyte protrusion of the posterior edge of the adjacent vertebral body of the diseased disc. All patients had symptoms of thoracic myelopathy before operation, and 7 of them had radiculopathy. Via transforaminal approach under local anesthesia, enlarged foraminoplasty and full-endoscopic thoracic discectomy were used for treatment. Observe the changes of postoperative imaging, pain symptoms and recovery of spinal cord function at 1 week, 3 months, 6 months and 1 year after operation. Back pain and radicular pain were scored with VAS, neurological function was assessed with Nurick score and mJOA score, and thoracic spine function was assessed with Oswestry disability index (ODI). Results: All operations were successfully completed, and no intraoperative conversion of surgical methods occurred. Postoperative thoracic MRI and CT examinations of all patients showed that the spinal cord was fully decompressed without any residual compression. Back pain and radicular pain were all relieved obviously in all patients, and spinal cord function was obviously restored. Transient intercostal neuralgia occurred in 2 cases after operation, and no other surgical complications occurred. Conclusions: Full-endoscopic or fluoroscopic foraminoplasty and full-endoscopic thoracic discectomyvia transforaminal approach under local anesthesia is a safe and effective treatment for soft and hard thoracic disc herniation located on the ventral side of the spinal cord.

Spontaneous regression of calcified thoracic herniations: Can Hounsfield-units radiodensity have a predictive value?

INTRODUCTION

Spontaneous regressions of calcified thoracic disc herniations (TDH) have been rarely described. Since now, no previous papers hypothesized that radiological factors could be able to predict the evolution of the herniation. This study shows that the radiodensity of the herniated material in herniations with spontaneous resolution might differ from that of operated herniations.

METHODS

This is a retrospective study. A cohort of patients that underwent surgical removal of a calcified thoracic disc herniation has been compared to two cases conservatively treated and a case with spontaneous regression. CT scans were evaluated to compute the average radiodensity [in Hounsfield units (HU)] of the calcified components of the herniations. All the slices of the CT scans involving the calcification were evaluated in their axial images and in their coronal and sagittal reformations. Comparison of the slices radiodensity (spontaneously resolved versus surgically treated) was performed with the unpaired Student's t test.

RESULTS

The mean density of calcification in the case with spontaneous regression was found to be 454 HU. In the control group of surgical cases observed, and the conservatively treated cases, the mean HU density showed higher values (respectively, 827 and 853 HU) (p < 0.01).

CONCLUSION

Qualitative differences between calcified TDH that resolve spontaneously or need surgical treatment might be shown by differences of radiodensity. This comparative study, in spite of the limitations due to small numbers, provides a new insight in the interpretation of the phenomenon of spontaneous resolution of calcified TDH. These slides can be retrieved under Electronic Supplementary Material.

Transthoracic Discectomy for Symptomatic Thoracic Disc Herniation: 2-Dimensional Operative Video

Thoracic disc herniations are an infrequent occurrence, but can be a cause of significant myelopathy. Diagnosis typically requires a high clinical suspicion that is confirmed with appropriate imaging. Classically, the transthoracic approach for discectomy is the treatment of choice for symptomatic cases. This video concerns a 48-yr-old woman who presented with worsening mid-back pain and progressive gait difficulty. Her examination was significant for proximal lower extremity muscle weakness, difficulty with tandem gait, and urinary incontinence. Imaging demonstrated a large T7-8 disc herniation causing severe spinal cord compression. The patient underwent T7-8 transthoracic discectomy and interbody fusion. She tolerated the procedure well without complication, and postoperative imaging demonstrated decompression of her spinal cord. On follow-up, she had improved mid-back pain, strength, and ambulatory function. The patient consented to the recording of this surgical video for potential publication.

Complications Associated with Surgery for Thoracic Disc Herniation: A Systematic Review and Network Meta-Analysis

BACKGROUND

A systematic review and network meta-analysis (Prospero ID CRD42018106936) were performed.

OBJECTIVE

The selection of the appropriate surgical approach for the management of thoracic disc herniation (TDH) is often challenging because of the frequency and variability of the associated complications. We evaluated the safety of the surgical approaches for TDH by estimating the mortality (Q1) and morbidity (Q2), and frequency of the most common complications (Q3).

METHODS

We searched the medical literature for randomized controlled trials and observational studies reporting on the management of TDH. Postoperative complications were the outcome of interest. The absolute and relative risk estimates, along with the rank probability scores, were estimated for each approach, through a network meta-analysis. The results were read in the light of the quality of the available evidence.

RESULTS

Fifteen studies with a total of 1036 patients fulfilled our eligibility criteria. Three deaths were reported. The overall morbidity was as high as 29%, largely attributed to medical (21%; 95% confidence interval [CI], 10%-38%), surgical site (11%; 95% CI, 5%-22%), cerebrospinal fluid-related (8%; 95% CI, 3%-8%), and neurologic complications (5%; 95% CI, 1%-24%). The anterior and lateral approaches were associated with a higher risk for medical and surgical complications compared with the posterolateral approach.

CONCLUSIONS

Surgery for TDH is associated with minimal mortality but significant morbidity, with large variations among the available approaches. An understanding of the perioperative complications rates is important to develop complication avoidance strategies and to aid accurate patient-to-doctor communication.

Elevated inflammatory cytokine expression in CSF from patients with symptomatic thoracic disc herniation correlates with increased pain scores

BACKGROUND

The pathophysiology of pain in patients with symptomatic thoracic disc herniation (TDH) remains poorly understood. Mere mechanical compression of the spinal cord and/or the exiting nerve root by a prolapsed disc cannot explain the pathogenesis of pain in all cases. Previous studies report a direct correlation between the levels of proinflammatory cytokines in disc biopsies and the severity of leg pain in patients with lumbar disc herniation. A similar correlation in patients with TDH has not been investigated.

PURPOSE

To correlate the cerebrospinal fluid (CSF) expression of cytokines and pain-related amino acids with preoperative pain scores in patients with symptomatic TDH.

STUDY DESIGN

A prospective human study of CSF samples and clinical outcome scores.

METHODS

Using enzyme-linked immunosorbent assay (ELISA) and high-performance liquid chromatography (HPLC), we determined inflammatory cytokine levels (TNF-α, IL-1β, and IL-10) and amino acid levels (glutamate, aspartate, gamma-aminobutyric acid, glycine, and arginine) in CSF samples from 10 patients with TDH and 10 control subjects who did not suffer an inflammatory disease nor pain related to spinal cord compression and subsequently correlated these levels with preoperative pain scores. Differences between both groups were evaluated by a Mann-Whitney U test. In order to estimate the correlation between cytokine or amino acid expression and pain scores, data were analyzed using a linear regression analysis.

RESULTS

No inflammatory cytokines were found in CSF samples from control subjects, whereas TNF-α, IL-1β, and IL-10 were detectable by ELISA in all CSF samples from patients with TDH. TNF-α and IL-10 but not IL-1β levels moderately correlated with preoperative pain scores. Elevated TNF-αlevels positively correlated with high pain scores; elevated IL-10 levels negatively correlated with high pain scores. Amino acids were detectable in all samples from both groups. There were no significant differences between the groups in any of the amino acids measured with HPLC.

CONCLUSION

Increased proinflammatory cytokine expression is associated with elevated pain scores in patients with symptomatic TDH. On the other hand, there is no conclusive correlation between the intensity of pain and the local or systemic presence of amino acids associated with pain transmission.

Surgical treatment of thoracic disc herniation: an overview

BACKGROUND

Surgical treatment of thoracic disc herniation (TDH) is technically demanding due to its proximity to the spinal cord.

METHODS

Literature review.

RESULTS

Symptomatic TDH is a rare condition predominantly localized between T8 and L1. Surgical indications include intractable back or radicular pain, neurological deficits, and myelopathy signs. Giant calcified TDH (> 40% spinal canal occupation) are frequently associated with myelopathy, intradural extension, and post-operative complications. Careful pre-operative planning helps reduce the risk of complications. Pre-operative CT and MRI identify the hernia's location and size, calcifications, and intradural extension. The approach must provide adequate dural sac visualization with minimal manipulation of the cord. Non-anterior approaches are favoured if they provide at least equal exposure than anterior approach owing to higher risk of pulmonary morbidity associated with anterior approach. A transthoracic approach is recommended for central calcified herniated discs. A posterolateral approach is often suitable for non-calcified lateralized TDH. Thoracoscopic approaches are less invasive but have a substantial learning curve. Retropleural mini-thoracotomy is an acceptable alternative. Pre-operative identification of the pathological level is confirmed by intra-operative level check. Intra-operative cord monitoring is preferable but warrant further studies. Magnification and adequate lightening of the surgical field are paramount (microscope, thoracoscopy). Intra-operative CT scan with navigation is becoming increasingly popular since it provides real-time control on the decompression. Indications of fusion consist of pre-operative back pain, Scheuermann's disease, multilevel resection, wide vertebral body resection (> 50%), and herniation at thoracolumbar junction. Neurological deterioration, dural tear, and subarachnoid-pleural fistula are the most severe complications.

CONCLUSION

Further improvements are still warranted in thoracic spine surgery despite the advent of minimally invasive techniques. Intra-operative CT scan will probably enhance the safety of the TDH surgery.

Prevalence and Distribution of Incidental Thoracic Disc Herniation, and Thoracic Hypertrophied Ligamentum Flavum in Patients with Back or Leg Pain: A Magnetic Resonance Imaging-Based Cross-Sectional Study

OBJECTIVE

This study is aimed to comprehensively assess the prevalence and distribution of thoracic disc herniation (TDH) or thoracic hypertrophied ligamentum flavum causing stenosis (HLFS) by magnetic resonance image (MRI) in patients with back or leg pain.

METHODS

The study participants included 2212 patients who underwent MRI evaluation for back or leg pain. The prevalence and distribution of TDH or thoracic HLFS were assessed using lumbar MRI with cervicothoracic sagittal images. The presence of TDH or HLFS and the clinical parameters such as age, sex, lumbar surgical need, and thoracic operation were retrospectively reviewed. Logistic regression analysis of the data was followed.

RESULTS

The prevalence rates of TDH and thoracic HLFS in all patients were 6.5% (145/2212) and 19.0% (421/2212), respectively. The prevalence of TDH was demonstrated as a relatively even distribution across age groups, higher in male participants (8.0%) than in female participants, and more frequent in patients with lumbar surgical lesions (8.2%) than without surgical lesions. Whereas, the prevalence of thoracic HLFS tended to increase with age, was higher in female participants (21.6%) than in male participants, and had no association with presence of lumbar surgical lesions. The most frequently involved segments of TDH and HLFS were T8/9 and T10/11, respectively. Six of 145 patients with TDH and 15 of 421 patients with HLFS underwent surgery.

CONCLUSIONS

The prevalence of TDH had a significant association with the presence of lumbar surgical lesions and no association with age. The prevalence of thoracic HLFS had a strong association with age and no association with lumbar surgical lesions.

Transpedicular Approach to Thoracic Disc Herniaton Guided by 3D Navigation System

BACKGROUND

The choice of surgical approach for thoracic disc herniation should consider the location on the axial plane and the consistency of the herniated disc. Calcified midline disc herniations are difficult to remove with a transpedicular approach because of limitations due to blind spots; so they are usually treated via a transthoracic approach, although this entails a high risk of thoracopulmonary injuries.

METHODS

In this work we present two cases of calcified midline thoracic disc herniations treated with a transpedicular approach, improved by using a three-dimensional (3D) neuronavigation system to verify the extent of removal on the blind side.

RESULTS

Postoperative computed tomography (CT) scans demonstrated that this original technical innovation, in the two present cases, allowed us to reach the side opposite the disc herniation and to assess the extent of resection at the end of the procedure.

CONCLUSIONS

The employment of a neuronavigation system in the transpedicular approach allowed safe and effective removal of calcified midline thoracic disc herniations. We did not observe any postoperative neurological worsening, onset of spinal instability, or other adverse events.

Modified eggshell procedure via posterior approach for sclerosing thoracic disc herniation: a preliminary study

BACKGROUND

Clinically, sclerosing thoracic disc herniation is a disease with high surgical risk and various complications. Eggshell procedure is a surgical method used by surgeons to treat sclerosing thoracic disc herniation. The aim of this study was to report a modified eggshell procedure to treat sclerosing thoracic disc herniation.

METHODS

Medical records of 25 patients with sclerosing thoracic disc herniation were collected between 2007/01 and 2010/08, including 14 males and 11 females, with an average age of 51.7 years old. Modified eggshell procedure was performed to treat the patients with sclerosing thoracic disc herniation. All patients were followed up. Japanese Orthopaedic Association (JOA) score was used to evaluate the clinical outcomes.

RESULTS

All operations were performed successfully with complication rate of 12 %. There were 2 cases of dural laceration and 1 subdural hematoma. All included patients were followed up for at least 5 years, with the median of 6 years. JOA score of preoperation was 5 (IQR = 1) while it was 8 (IQR = 2) at final follow-up, with significant difference (Mann-Whitney U test, Z = -4.891, P < 0.001). The improvement rate of neurological status was 51.5 ± 23.1 %. According to the classification of improvement rate, there were 15 cases at good level, 8 cases at moderate level, and 2 cases without any improvement.

CONCLUSIONS

Modified eggshell procedure is a safe and effective surgical method when performed to treat sclerosing thoracic disc herniation in the clinical practice.

Abducens nerve palsy as a postoperative complication of minimally invasive thoracic spine surgery: a case report

Background

Thoracic disc surgeries make up only a small number of all spine surgeries performed, but they can have a considerable number of postoperative complications. Numerous approaches have been developed and studied in an attempt to reduce the morbidity associated with the procedure; however, we still encounter cases that develop serious and unexpected outcomes.

Case Presentation

This case report presents a patient with abducens nerve palsy after minimally invasive surgery for thoracic disc herniation with an intraoperative spinal fluid fistula. A literature review of all cases related to this complication after spine surgery is included.

Despite the uncommon nature of this type of complication, understanding the procedure itself, the principle occurrences and outcomes following the procedure, the physiopathogical features of abducens nerve palsy, and the possible adverse effects of spinal surgery, including minimally invasive procedures, can enable an early diagnosis of complications and facilitate the procedure.

Conclusions

In spite of being very rare and multifactorial, uni- or bilateral abducens nerve paralysis carries significant morbidity and can occur as a postoperative complication after conventional or minimally invasive spine surgery. This condition requires an accurate diagnosis and adequate multidisciplinary follow up.

Calcific discitis with giant thoracic disc herniations in adults

PURPOSE

Calcific discitis is a self-limiting process most commonly seen in the cervical spine of children. Rare literature exists regarding the natural history and management of this condition in adults, especially when it presents as a giant thoracic disc herniation into the spinal canal. Giant herniations in the thoracic spine are typically surgically removed to reduce the chance of permanent neurologic deficit from spinal cord compression. However, when associated with calcific discitis, they may undergo spontaneous regression with the need for surgery obviated.

METHODS

Medical records and radiographic studies of two adult patients with calcific discitis and myelopathy due to spinal cord compression by giant thoracic disc herniations were retrospectively reviewed. Search of the literature on calcific discitis in adults and spontaneous regression of calcified thoracic disc herniations was separately performed.

RESULTS

Both patients were young male adults presenting with back pain and early signs of myelopathy. With restriction of activities and oral NSAIDs, their symptoms were relieved within 3 months. Four adult cases of calcific discitis (characteristic central calcification confined within the nucleus pulposus) and three instances of spontaneous regression of small- to medium-sized thoracic calcified disc herniations were identified from the literature.

CONCLUSIONS

The demonstration of spontaneous resorption of giant calcified thoracic disc herniations in two adult patients with calcific discitis supplements the existing literature and provides the first evidence that giant calcified thoracic disc herniations may still undergo spontaneous remission and a "wait and watch" strategy may be justified at least in the initial management of these patients, even with the presence of mild myelopathy.

Experience in the treatment of thoracic herniated disc using image-guided thorascopy

Thoracoscopic micro-discectomy is a treatment option for thoracic disc disease that combines the advantages of the anterior approach and the benefits of a minimally invasive technique. Adding a navigation system provides many advantages to the usual technique, as it allows accurate marking of the lesion level, improvement in the surgical approach, and precise control of herniated disc resection and vertebral osteotomy. The navigation system also reduces the learning curve for thoracoscopic technique. We report our experience in the treatment of thoracic disc herniation with image-guided thoracoscopy.

Ultrasound-guided posterolateral approach for midline calcified thoracic disc herniation

Objective

Symptomatic thoracic disc herniation often requires prompt surgical treatment to prevent neurological deterioration and permanent deficits. Anterior approaches offer direct visualization and access to the herniated disc and anterior dura but require access surgeons and are often associated with considerable postoperative pain and pulmonary complications. A disadvantage with using posterior approaches in the setting of central calcified thoracic disc herniation however, has been the limited visualization of anterior dura and difficulty to accurately assess the extent of decompression.

Methods

We report our experience with intraoperative ultrasound (US) guidance during a modified posterior transpedicular approach for removal of a central calcified thoracic disc herniation with a review of pertinent literature.

Results

The herniated thoracic disc was successfully removed with posterior approach with the aid of intraoperative US. The patient had significant neurological improvement at three months follow-up.

Conclusion

Intraoperative ultrasound is a simple yet valuable tool for real-time imaging during transpedicular thoracic discectomy. Visualization provided by intraoperative US increases the safety profile of posterior approaches and may make thoracotomy unnecessary in a selected group of patients, especially when a patient has existing pulmonary disease or is otherwise not medically fit for the transthoracic approach.

Thoracic disc herniation leads to anterior spinal artery syndrome demonstrated by diffusion-weighted magnetic resonance imaging (DWI): a case report and literature review

BACKGROUND

Thoracic disc herniation rarely causes acute ischemic events involving the spinal cord. Few reports have suggested this as a mechanism leading to anterior spinal artery syndrome, and none with illustration through diffusion-weighted magnetic resonance imaging (DWI).

PURPOSE

The purpose of this study was to report a case of anterior spinal artery syndrome secondary to thoracic disc herniation and demonstrate the first use of DWI to aid in diagnosis of this rare myelopathy.

STUDY DESIGN

Case report.

METHODS

A 36-year-old woman developed sudden onset of back pain followed by evolving paraparesis and sensory loss consistent with anterior spinal artery distribution ischemia. T2-weighted magnetic resonance imaging (MRI) demonstrated an acute herniated nucleus pulposus at the T7-T8 disc, which produced a focal indentation of the adjacent anterior spinal cord without cord displacement or canal stenosis. T2-weighted hyperintensities were seen at T4-T7 levels with corresponding brightness on DWI and reduction of the apparent diffusion coefficient, consistent with cord ischemia.

RESULTS

Remarkably, within just a few days and following conservative treatment, including heparin and steroids, this patient's neurologic status began to show improvement. Within 3 weeks, she was ambulating with assisted devices, and at the 10-month follow-up, the patient had nearly complete neurological improvement. A follow-up MRI at 10 months showed normal T2-weighted imaging except for a 1×2-mm area of anterior-left lateral cord myelomalacia at T4-T5.

CONCLUSIONS

Acute thoracic disc herniation with cord contact but without canal stenosis is able to disrupt blood flow to the cord leading to anterior spinal artery distribution ischemia. This case represents the first demonstrated use of DWI in diagnosing this rare cause of anterior spinal artery ischemia.

Acute paraplegia secondary to thoracic disc herniation of the adjacent segment following thoracolumbar fusion and instrumentation

Proximal junctional disease is a well-recognized postoperative phenomenon in adults who are undergoing long thoracolumbar fusion and instrumentation, and is attributed to increased a junctional stress concentration. In general, the onset of symptoms in these patients is insidious and the disease progresses slowly. We report on a contrary case of rapidly progressing paraplegia secondary to acute disc herniation at the proximal adjacent segment after long posterior thoracolumbar fusion with cement augmentation at the upper instrumented vertebra and the supra-adjacent vertebra. The patient was treated with a discectomy through the costo-transverse approach combined with extension of the posterior instrumentation. The patient's neurological status improved markedly. Stress concentration at the proximal junction disc space may have caused accelerated disc degeneration which in turn lead to this complication.

Posterior epidural migration of thoracic disc fragment

Migration of a disc fragment to the posterior epidural space is rare, especially in the thoracic spine. Only four such cases of posterior epidural migration of thoracic disc fragments have been reported. The authors report a case of 66-year-old man who presented with back pain and right leg weakness due to posterior epidural migration of thoracic disc fragment. The patient was successfully treated by laminectomy and partial facetectomy with disc removal.