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.

Uniportal Thoracic Endoscopic Unilateral Laminotomy with Bilateral Decompression of Thoracic Ossification of Ligamentum Flavum: A Systematic Review of Current Literature

BACKGROUND

Thoracic ossification of ligamentum flavum (TOLF) is a rare disease that often results in worsening neurologic sequelae if left untreated. Although the gold standard treatment for TOLF is open posterior laminectomy, it is often accompanied by high rates of complications and perioperative morbidity. There have been studies looking into feasibility of endoscopic posterior decompression for TOLF, citing potential for lower perioperative morbidity and achieving similar functional outcomes to its open laminectomy counterparts. We provide an up-to-date systematic review of clinical outcomes after endoscopic posterior decompression for TOLF from the latest assemblage of evidence.

METHODS

A systematic review of the technique was conducted from May 2000 to May 2023. Articles were selected based on PRISMA guidelines. Eligibility of studies was independently by 2 reviewers, with disagreements resolved by a third author.

RESULTS

Nineteen primary references comprising 337 patients with TOLF who underwent endoscopic posterior decompression were included in the systematic review. Mean follow-up time across all studies ranged from 8.9 to 65.3 months. Mean age ranged from 51.2 to 63 years, with mean intraoperative blood loss ranging from 15 to 62 mL. There is significant improvement in visual analog scale (VAS) score, VAS back, VAS leg, modified Japanese Orthopaedic Association score, and Oswestry Disability Index compared with preoperative recorded values across all studies, with low rates of complications reported.

CONCLUSIONS

Endoscopic posterior spinal decompression is a safe and effective technique for treatment of TOLF, with a low rate of complications and improvement in pain and function.

Surgical outcomes of percutaneous endoscopic thoracic decompression in the treatment of multi-segment thoracic ossification of the ligamentum flavum

BACKGROUND

Previous studies have demonstrated satisfactory outcomes of percutaneous endoscopic thoracic decompression (PETD) for single-segment thoracic ossification of the ligamentum flavum (TOLF). However, the clinical outcomes of PETD in patients with multi-segment TOLF (mTOLF) remain unclear. The aim of the present study was to evaluate the efficacy and safety of PETD for patients with multi-segment mTOLF.

METHODS

Eighteen consecutive patients (41 segments) with mTOLF were treated with PETD between January 2020 and December 2021. The clinical outcomes were evaluated using the modified Japanese Orthopaedic Association (mJOA) score and Visual Analog Scale (VAS), whereas radiographic parameters were measured by cross-section area of the spinal canal and anteroposterior diameter of the spinal cord.

RESULTS

The follow-up period ranged from 14 to 34 months. The mean operation time and blood loss were 154.06 ± 32.14 min and 61.72 ± 12.72 ml, respectively. Hospital stay after first-stage operation was 10.89 ± 2.42 days. The mJOA score and VAS score significantly improved at the final follow-up, with a mean mJOA recovery rate of 63.3 ± 21.90%. The incidence of complications was 12.2% per level. The radiographic outcomes showed adequate decompression of the spinal cord.

CONCLUSIONS

The present study demonstrates that PETD is effective and safe as a minimally invasive procedure to treat patients with mTOLF. All patients showed relief of their symptoms and improvement in neurological function.

CT-based radiographic measurements and effectiveness estimates of full-endoscopic surgery in thoracic myelopathy caused by ossification of ligamentum flavum

BACKGROUND

Evaluate the effectiveness of posterior percutaneous full-endoscopic technique for patients with thoracic myelopathy caused by ossification of ligamentum flavum (TOLF).

METHODS

A prospective study was conducted for 16 patients with TOLF, who were treated with posterior endoscopic technique from 2017 to 2019. The sagittal and cross-sectional CT images are used to measure the area of ossified ligamentum and evaluate the decompression of surgery, respectively. The effectiveness was evaluated with visual analog scale (VAS), modified Japanese Orthopedic Association scale (mJOA), The Oswestry Disability Index (ODI), and Macnab efficacy evaluation.

RESULTS

The average area of TOLF on sagittal and cross-sectional CT images in the 16 patients was (116.62 ± 32.72) mm² and (141.59 ± 27.25) mm² preoperatively, (15.99 ± 12.54) mm² and (11.72 ± 8.64) mm² at 3 days after the operation, (16.78 ± 11.49) mm² and (10.82 ± 7.57) mm² postoperative 1 year, respectively. The invasive proportion of spinal canal at preoperative sagittal and cross-sectional CT images was (48.10 ± 10.04) % and (57.58 ± 11.37) %, which decreased to (6.83 ± 4.48) % and (4.40 ± 3.01) % at the final follow-up. The average score of mJOA, VAS and ODI improved. The excellent and good rate was 87.50% according to Macnab evaluation. Compared with preoperative, differences in areas of TOLF, proportions of spinal canal, and clinical assessments of postoperative 3 days and 1 year were all statistically significant. Two cases of dural tear were observed.

CONCLUSION

Endoscopic surgery has a good clinical effect on TOLF, which has the advantage of less trauma to the paraspinal muscles and no impact on the spinal structure. The CT-based radiographic measurements can quantitatively evaluate the degree of spinal canal stenosis in TOLF.

Zoning laminectomy for the treatment of ossification of the thoracic ligamentum flavum

OBJECTIVE

Spinal cord injury is a common occurrence during spinal surgery. In this study, we proposed a zoning laminectomy, which could reduce the incidence of nerve injury. We also discussed the safety and clinical efficacy of the zoning laminectomy for thoracic ossification of the ligamentum flavum (TOLF).

METHODS

Forty-five patients with TOLF who underwent zoning laminectomy from October 2016 to February 2020 were included in the retrospective analysis. The Japan Orthopedic Association (JOA) score was used to evaluate clinical outcomes. Meanwhile, the occurrence of complications was recorded.

RESULTS

All 45 patients underwent the operation successfully, and the mean follow-up period was 25.3 months, the mean operation time was 160.2 min, the average blood loss was 474.2 ml, and the average hospital time was 8.0 days. At the final evaluation, the JOA score was significantly higher than the preoperative JOA score (P < 0.001) and the overall recovery rate of the JOA score averaged 69.6%. Seventeen patients were graded as excellent, twenty-six as good, and two as fair. The complications included dural tears in nine patients (20.0%), cerebrospinal fluid leakage in seven patients (15.6%), deep infection in one patient (2.2%), and epidural hematoma in one patient (2.2%). All patients recovered well after treatment. Besides, there was no neurological deterioration and thoracic kyphosis occurred.

CONCLUSIONS

Zoning laminectomy adopts a phased resection from "safe zone" to "danger zone" and defines the safe removal range of the lamina, which reduces the risks of spinal cord injury caused by instrument manipulation. Therefore, it is a safe and effective surgical option.

Comparison of the Short-Term Efficacy of Percutaneous Endoscopic Thoracic Decompression and Laminectomy in the Treatment of Thoracic Ossification of the Ligamentum Flavum

OBJECTIVE

This study aimed to investigate the short-term efficacy of percutaneous endoscopic thoracic decompression (PETD) under local anesthesia and traditional posterior thoracic laminectomy (PTL) in treating single-segment thoracic ossification of the ligamentum flavum (T-OLF).

METHODS

This was a retrospective review of the clinical information of 52 patients with T-OLF between September 2017 and September 2021. Based on the inclusion criteria, a total of 52 patients were included in the present research, 26 in the PETD group and 26 in the PTL group. The general preoperative data, intraoperative surgical conditions, preoperative and postoperative clinical information, and complications were collected. The modified Japanese Orthopedic Association score and recovery rate were evaluated preoperatively and at 3, 6, and 12 months postoperatively.

RESULTS

There was no statistically significant difference in the baseline parameters in either group (P > 0.05). There were statistically significant differences in operation time (94.62 vs. 144.62 minute) and blood loss (22.12 vs. 287.69 mL) between the PETD group and the PTL group. The modified Japanese Orthopedic Association score in the 2 groups improved from (5.46 ± 1.10) and (5.69 ± 1.01) preoperatively to (9.08 ± 0.90) and (8.88 ± 1.07) at 12 months postoperatively. The recovery rate was 84.6% in the PETD group and 76.9% in the PTL group. In addition, the complications in the PETD group were fewer than those in the PTL group.

CONCLUSIONS

The PETD under local anesthesia for T-OLF has many advantages, such as high patient acceptance, good short-term clinical outcomes, and few complications; therefore, this procedure should be promoted as a viable treatment option for T-OLF.

Clipping and exclusion of a thoracic pial arteriovenous fistula with multiple shunting points: how I do it

BACKGROUND

Thoracic pial arteriovenous fistulas (pAVFs) are rare vascular malformations that usually consist of a single dilated pial artery connecting directly to an enlarged draining vein. Multiple shunting point thoracic pAVFs are even rarer entities causing progressive myelopathy.

METHOD

We present our surgical technique to identify and exclude multiple shunting point thoracic pAVF with appropriate pre-operative planning. This surgical technique is illustrated by an intraoperative video.

CONCLUSION

Double injection pre-operative angiography represents a helpful tool to plan the surgery. Intraoperative exposure with pedicle removal and the use of micro-Doppler improve the identification and the exclusion of a multiple shunting thoracic pAVF.

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.

Spinal extradural arachnoid cyst: A rare cause of thoracic myelopathy

A spinal extradural arachnoid cyst (SEAC) is a rare condition which can lead to back pain, radiculopathy, and compressive myelopathy. It accounts for approximately 1% of spinal tumours. The exact aetiology of SEACs is not well understood; however, this study is supportive of a traumatic aetiology of this disease in addition to supporting a uni-directional valve as a mechanism of CSF accumulation. The purpose of this study is to review the presentation, work-up, treatment and postoperative course of a patient with SEAC. We present the case of a 40-year-old male with a history of trauma who developed a SEAC and was treated surgically at our unit. Although a rare disease, we highlight the importance of early diagnosis and surgical treatment as it is a surgically curable disease with a good postoperative prognosis.

•

SEAC is an important differential diagnosis for compressive myelopathy.

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Trauma may be an underlying cause of SEAC development.

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Uni-directional valve is the likely mechanism of CSF accumulation in a SEAC.

Angled Ultrasonic Bone Curette-Assisted Circumferential Decompression for Thoracic Myelopathy Caused by Severely Anterior Ossification

Objective

Thoracic myelopathy caused by severe anterior ossification is often progressive and fails to respond to conservative treatment. Removal of the compressing ossification is the most effective method but is hard to operate. In this study, we describe a novel one‐stage posterior circumferential decompressive procedure assisted by an angled ultrasonic bone curette (UBC) for thoracic myelopathy caused by severe anterior ossification and evaluate its safety and efficacy.

Methods

The current study enrolled 15 consecutive patients (five men and 10 women) with thoracic myelopathy caused by severely anterior ossification between January 2017 and December 2019. All patients underwent posterior circumferential decompression assisted by angled UBC and segmental instrumentation with interbody fusion. At the time of surgery, the average age was 58.6 ± 6.3 years (47–70 years). Before and after surgery, the patient data, clinical manifestation, operative levels, blood loss, operative time, perioperative complications, Japanese Orthopaedic Association (JOA) score were recorded and analyzed retrospectively.

Results

All patients had successful one‐stage posterior circumferential decompression to remove anterior ossifications directly. There were 12 cases of OPLL, two cases of a calcified giant herniated disc, and one case of osteophyte. The average operation time was 153.4 ± 53.4 min (77–242 min), with a mean blood loss of 463.5 ± 155.8 mL (240–780 mL). The average length of stay in the hospital was 14.3 ± 4.7 days (9–25 days) and the mean follow‐up duration was 20.8 ± 8.8 months (12–39 months). Almost all patients had subjective improvement in motor power and gait. The average preoperative JOA score was 4.5 ± 1.6, which improved to 9.0 ± 1.8 at the final follow‐up. Postoperative differences in the overall JOA scores showed significant improvement (F = 105.446, p < 0.01). The overall recovery rate at the final examination scored 70.9% ± 25.0%. According to Hirabayashi's classification, eight cases were rated as excellent, four as good, two as fair, and one as unchanged. No patient was graded as deteriorated. Two patients (13.3%) experienced intraoperative cerebrospinal fluid leakage, while two cases (13.3%) experienced unilateral intercostal neuralgia, and only one (6.7%) encountered acute neurological deterioration. All these patients were treated conservatively and their neurological function improved significantly. At the follow‐up, there was no evidence of neurological deterioration.

Conclusion

Circumferential decompression assisted by angled UBC can preserve more posterior elements of the involved levels, maintaining an intact pleura and reducing the operation time and blood loss for thoracic myelopathy caused by severe anterior ossification. It is a safe, effective, and technically feasible method to provide surgeons with a new option for thoracic spinal circumferential decompression.

A new "de-tension"-guided surgical strategy for multilevel ossification of posterior longitudinal ligament in thoracic spine: a prospective observational study with at least 3-year follow-up

BACKGROUND CONTEXT

Multilevel ossification of the posterior longitudinal ligament in thoracic spine (mT-OPLL) is a rare but clinically significant spinal condition. Various surgical methods have been developed to address this disease. However, the outcomes are commonly unfavorable, and no standard surgical strategy has been established. To solve this problem, we introduced a new surgical strategy based on an innovative decompression concept, namely "de-tension."

PURPOSE

This study aimed to investigate the safety and efficacy of this new treatment, and to establish an improved surgical strategy.

STUDY DESIGN

A prospective observational study with at least 3 years of follow-up.

PATIENT SAMPLE

Fifty-one patients with consecutive mT-OPLL who were treated between August-2012 and June-2018 were enrolled in this study.

OUTCOME MEASURES

A modified Japanese Orthopedic Association (mJOA) scale assessing thoracic spine, recovery rate (RR), and surgical complications.

METHODS

All patients underwent 1-stage thoracic posterior laminectomy, selective OPLL resection, and spinal column shortening with/without reduction of kyphosis (dekyphosis). Initially, we recommended that when thoracic kyphosis of T1-T12 in sagittal reconstruction CT (TK) was less than 20°, no dekyphosis should be performed; when this angle was greater than 20°, dekyphosis could be conducted. Patients' demographic data, radiological findings, and intra/postoperative complications were recorded and analyzed. Neurological status was evaluated with mJOA score and RR. The correlation of preoperative TK or kyphosis angle in fusion area (FSK) with postoperative dekyphosis angle and spinal column shortening distance (SD) were respectively evaluated by Pearson correlation analysis.

RESULTS

Cerebrospinal fluid leakage (58.8%) and neurological deterioration (15.7%) were the most common complications. Average mJOA score was improved from preoperative 4.0±2.1 to 8.9±2.4 at the last follow-up, and the mean RR was 71.3±33.7%. There was no correlation between preoperative TK and SD (p=.56) or between preoperative FSK and SD (p=.21), but dekyphosis angle was significantly correlated with TK (r=0.504, p<.01) and FSK (r=0.5734, p<.01). TK of 24.6° and FSK of 23.0° were determined as the critical angles for dekyphosis, and a modified surgical strategy was formulated.

CONCLUSIONS

This new strategy provided a novel solution for mT-OPLL, and was proved to be safe and effective during long-term follow-up. Further rigorously designed large-scale prospective studies are needed to validate our findings.

Unilateral biportal endoscopic decompression for symptomatic thoracic ossification of the ligamentum flavum: a case control study

PURPOSE

Thoracic ossification of the ligamentum flavum (OLF) is an uncommon disease that mostly occurs in East Asians. Laminectomy is often considered when patients develop neuro-related symptoms but may associate with treatment-related complications. This study aimed to evaluate the efficacy and safety of unilateral biportal endoscopic (UBE) decompression treatment in patients with symptomatic OLF.

METHODS

From January 2020 to January 2021, patients with spinal cord compression symptoms and imaging-defined single-level thoracic OLF were enrolled in this study and received UBE decompression treatment. Their pre- and postoperative neurological statuses were evaluated by the modified Japanese Orthopaedic Association (mJOA) score, Visual Analog Scale (VAS) for leg pain, and Frankel grade.

RESULTS

Fourteen patients with an average age of 59.4 years were enrolled in the study. The mean operation time was 66.1 ± 15.4 minutes. Patients were followed up for at least one year after receiving the treatment. Our data suggested that their mJOA score (preop 6.2 ± 1.2, 1 year 8.5 ± 0.9; P < 0.001) and VAS score (preop 4.5 ± 2.0, 1 year 0.5 ± 0.9; P < 0.001) were significantly improved compared with that before operation. Cerebrospinal fluid leakage occurred in one patient, head and neck pain occurred in two patients, and hyperalgesia of lower limbs occurred in two patients. All these complications did not cause serious consequences.

CONCLUSION

This primary study indicated that the UBE decompression treatment can achieve satisfactory clinical results in patients with thoracic OLF at single level and provide an alternative treatment option.

Comparison of percutaneous endoscopic thoracic decompression and posterior thoracic laminectomy for treating thoracic ossification of the ligamentum flavum: a retrospective study

Background

Thoracic spinal stenosis (TSS) caused by ossification of the ligamentum flavum (OLF) is generally treated by surgical decompression. In this study, we compared the efficacy and safety of percutaneous endoscopic thoracic decompression (PETD) and posterior thoracic laminectomy (PTL) for treating thoracic ossification of the ligamentum flavum (TOLF).

Methods

Twenty consecutive patients with TSS caused by TOLF who were treated between April 2016 and May 2020 were included in this retrospective study. They were divided into the PETD (n = 11) and PTL (n = 9) groups. The mean follow-up period was 19.6 months. The visual analogue scale (VAS) score, the modified Japanese Orthopedic Association (mJOA) score and the recovery rate (RR) were used to evaluate the clinical outcomes.

Results

There were significant differences between PETD group and PTL group in operative time (min) (95.0 ± 18.8 vs 131.1 ± 19.0), postoperative drainage (mL) (20.2 ± 7.9 vs 586.1 ± 284.2), hospital stay (days) (4.4 ± 1.2 vs 10.4 ± 2.6) (P < 0.05 for all). However, both groups had similar and significant improvement in VAS and mJOA scores. The RR of two groups achieved the same improvement (81.8% VS 77.8%, P > 0.05).

Conclusions

The use of PETD and PTL for treating TOLF both achieved favorable outcomes. PETD is both minimally invasive and achieves similar postoperative symptom relief to PTL. Therefore, PETD could be considered as an effective alternative to traditional open surgery for TOLF in single-segment lower thoracic spine.

Multifocal spinal glioblastoma and leptomeningeal carcinomatosis in an elderly male with hydrocephalus and myelopathy

BACKGROUND

Primary spinal glioblastoma multiforme with multifocal leptomeningeal enhancement is rarely diagnosed or documented. We describe a rare case of multifocal spinal isocitrate dehydrogenase (IDH) wild type glioblastoma with leptomeningeal carcinomatosis in an elderly male presenting with a chronic subdural hematoma, progressive myelopathy, and communicating hydrocephalus.

CASE DESCRIPTION

A 77-year-old male with a medical history of an acoustic schwannoma, anterior cranial fossa meningioma, and immune thrombocytopenic purpura presented with right-sided weakness after repeated falls. Magnetic resonance imaging of the brain and spine demonstrated a left-sided subdural hematoma, leptomeningeal enhancement of the brain and skull base, ventricles, and the cranial nerves, and along with florid enhancement of the leptomeninges from the cervicomedullary junction to the cauda equina. Most pertinent was focal thickening of the leptomeninges at T1 and T6 with mass effect on the spinal cord. A T6 laminectomy with excisional biopsy of the lesion was planned and completed. Findings were significant for glioblastoma the World Health Organization Grade IV IDH 1 wild type of the thoracic spinal cord. Subsequently, his mental status declined, and he developed progressive hydrocephalus which required cerebrospinal fluid diversion. Unfortunately, the patient had minimal improvement in his neurological exam and unfortunately died 2 months later.

CONCLUSION

In a review of the limited literature describing similar cases of primary spinal glioblastoma, the prognosis of this aggressive tumor remains unfavorable, despite aggressive treatment options. The purpose of this report is to increase awareness of this rare condition as a potential differential diagnosis in patients presenting with multifocal invasive spinal lesions.

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.

Assessment of thoracic spinal cord electrophysiological activity through magnetoneurography

OBJECTIVE

Noninvasive and detailed visualization of electrophysiological activity in the thoracic spinal cord through magnetoneurography.

METHODS

In five healthy volunteers, magnetic fields around current flowing in the thoracic spinal cord after alternating unilateral and synchronized bilateral sciatic nerve stimulation were measured using a magnetoneurograph system with superconductive quantum interference device biomagnetometers. The current distribution was obtained from the magnetic data by spatial filtering and visualized by superimposing it on the X-ray image. Conduction velocity was calculated using the peak latency of the current waveforms.

RESULTS

A sufficiently high magnetic signal intensity and signal-to-noise ratio were obtained in all participants after synchronized bilateral sciatic nerve stimulation. Leading and trailing components along the spinal canal and inward components flowing into the depolarization site ascended to the upper thoracic spine. Conduction velocity of the inward current in the whole thoracic spine was 42.4 m/s.

CONCLUSIONS

Visualization of electrophysiological activity in the thoracic spinal cord was achieved through magnetoneurography and a new method for synchronized bilateral sciatic nerve stimulation. Magnetoneurography is expected to be a useful modality in functional assessment of thoracic myelopathy.

SIGNIFICANCE

This is the first report to use magnetoneurography to noninvasively visualize electrophysiological activity in the thoracic spinal cord in detail.

Comparison of Surgical Outcomes Between Staged and Simultaneous Decompression of Discontinuous Thoracic Ossification of the Ligamentum Flavum: A Retrospective Study

BACKGROUND

Discontinuous thoracic ossification of the ligamentum flavum (TOLF) is diagnosed according to the number and distribution of involved segments seen on magnetic resonance images. When TOLF causes thoracic myelopathy, surgical intervention for these lesions becomes unavoidable. However, there are few reports on the outcomes of surgery for discontinuous TOLF.

METHODS

The study included 26 patients of mean age 55.0 years who underwent simultaneous (n = 16) or staged (n = 10) decompression of discontinuous TOLF between July 2006 and June 2016. Final neurologic status was evaluated using the modified Japanese Orthopaedic Association (JOA) score. The surgical data and incidence of complications were compared. The mean follow-up duration was 73.3 months.

RESULTS

There was no between-group difference in number of levels decompressed or the amount of intraoperative blood loss. There was a significant improvement in the JOA score from 4.0 before surgery to 8.0 postoperatively, with an average recovery rate of 58.3%. The JOA recovery rate was significantly better in the staged group than simultaneous group (68.4% vs. 52.0%, P < 0.05). However, the incidence of complications was similar between the staged and simultaneous groups including for dural tear (1 vs. 6, P = 0.19), cerebrospinal fluid leak (4 vs. 6, P = 1.00), and transient neurologic deterioration (0 vs. 2, P = 0.51).

CONCLUSIONS

The surgical outcome of staged decompression for discontinuous TOLF seems to be better than that of simultaneous decompression. The complication rates of these 2 strategies are similar.

Comparison of Anterior and Posterior Surgical Approaches for Treatment of Thoracic Myelopathy

OBJECTIVE

To study a large multi-institutional sample of patients undergoing anterior versus posterior approaches for surgical decompression of thoracic myelopathy.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program was queried for patients who underwent decompression for thoracic myelopathy between 2007 and 2015 via anterior or posterior approaches. Patients were excluded if they were undergoing surgery for tumors to isolate a degenerative cohort. Demographics, patient comorbidities, operative details, and postoperative complications were compared between the 2 cohorts.

RESULTS

Although there were no differences in age (P = 0.06), sex (P = 0.72), or American Society of Anesthesiologists class (P = 0.59), there were higher rates of steroid use (P = 0.01) and hematologic disorders that predispose to bleeding (P = 0.04) at baseline in the posterior approach cohort. The posterior approach patients had longer operative times (P = 0.03), but there were no differences in length of stay (P = 0.64). Although there were no significant differences in the rates of major organ system complications or return to the operating room (P = 0.52), the posterior approach cohort displayed a trend toward increased severe adverse complications (29.8% vs. 17.6%, P = 0.28) compared with the anterior approach cohort.

CONCLUSION

Although the anterior approach to surgical decompression of thoracic myelopathy demonstrated a lower complication rate, this result did not reach statistical significance. The anterior approach was associated with significantly shorter mean operative time, but otherwise there were no significant differences in operative or postoperative outcomes. These findings may support the favorability of the anterior approach but warrant further investigation in a larger study.

Outcome of Thoracic Column Antedisplacement and Fusion in Treatment of Thoracic Myelopathy Caused by Ossification of Posterior Longitudinal Ligament: A Case Series Study

BACKGROUND

Up to date, surgical outcome of multilevel thoracic ossification of posterior longitudinal ligament (T-OPLL) with high canal occupation ratio is less satisfactory.

OBJECTIVE

To explore the result of thoracic column antedisplacement and fusion (TCAF) in treatment of multilevel T-OPLL with high canal occupation ratio.

METHODS

A total of 5 patients who underwent TCAF procedure for T-OPLL were retrospectively reviewed. Parameters including extent of OPLL, thickness of the maximal OPLL (max-OPLL), maximal canal occupying ratio (max-COR) of OPLL, effective canal diameter (ECD) at the max-OPLL level, antedisplacement distance of thoracic columns, ASIA grades, Japanese Orthopedic Association (JOA) scores, and complications were collected and analyzed at preoperation and the last follow-up.

RESULTS

All patients (5 F, mean age 61.0 yr, mean follow-up 18.0 months) underwent TCAF successfully and no spinal cord injury or cerebrospinal fluid leakage occurred. The mean extent of OPLL was 2.8 vertebral bodies. The mean preoperative thickness of the max-OPLL was 5.9 mm. The average antedisplacement distance of thoracic columns was 5.6 mm. The mean ECD was improved from 6.5 mm to 10.9 mm, and the max-COR was improved from 50.7% to 7.1% at last follow-up. Two patients showed improvement in ASIA grades and JOA scores were significantly improved from 5.6 points to 10.4 points at final follow-up. The overall therapeutic results of 1 patient were classified into good and 4 into fair at last follow-up.

CONCLUSION

TCAF may be a safe and effective procedure in treatment of multilevel T-OPLL with high canal occupation ratio.

Ultrasonic Osteotome Assisted Full-Endoscopic en Block Resection of Thoracic Ossified Ligamentum Flavum: Technical Note and 2 Years Follow-up

BACKGROUND

Conventional open laminectomy is considered to be the standard procedure for the treatment of thoracic ossified ligamentum flavum, but multi-segment thoracic laminectomy extensively removes the facet joints and ligamentous tissue, destroying the thoracic spine biomechanics and stability, may lead to delayed thoracic spine kyphosis deformities, which in turn can lead to potential neurological deterioration and local intractable pain.

OBJECTIVE

To introduce the technical notes and clinical outcome of ultrasonic osteotome assisted full-endoscopic en block resection of thoracic ossified ligamentum flavum.

STUDY DESIGN

A prospective cohort study.

SETTING

Hospital and outpatient surgery center.

METHODS

From January 2017 to March 2018, 15 patients with 1 - 2 segment thoracic ossified ligamentum flavum were treated with ultrasonic osteotome assisted full-endoscopic en block resection of thoracic ossified ligamentum flavum under local anesthesia. The magnetic resonance imaging and computed tomography of the thoracic spine was reexamined after the operation to evaluate the completeness of ossified ligamentum flavum resection and spinal cord decompression. The patients were followed up on the visual analog scale of back pain and radicular pain, Nurick score and mJOA score of neurological function, and Oswestry Disability Index at 1 week, 3 months, 6 months, one year, and 2 years after operation.

RESULTS

All operations of 17 segments thoracic ossified ligamentum flavum in 15 patients were successfully completed without intraoperative conversion to open surgery. There were no intraoperative spinal cord injuries, dura tears, postoperative cerebrospinal fluid leakage, postoperative infections, and postoperative spinal cord injury aggravated symptoms. Postoperative thoracic spine magnetic resonance imaging and computed tomography examinations of all patients showed that the spinal cord was fully decompressed without any residual pressure. Back pain and radicular pain were relieved significantly, and spinal cord function (Nurick, mJOA, and Oswestry Disability Index scores) was obviously restored. The mJOA recovery rate at the 2-year follow-up was 78.3% in average.

LIMITATIONS

This is an observational cohort study with relative small sample and short-term follow-up.

CONCLUSIONS

Ultrasonic assisted full-endoscopic en block resection of ossified ligamentum flavum is a safe and effective minimally invasive spine surgery for thoracic myelography caused by thoracic ossified ligamentum flavum.

Surgical outcomes of the thoracic ossification of ligamentum flavum: a retrospective analysis of 61 cases

Background

Thoracic ossification of ligamentum flavum (T-OLF), as one of the causes of thoracic myelopathy, is often combined with other spinal disorders. Concurrent lumbar spinal canal stenosis (LCS) is often obscured by symptoms due to T-OLF, leading to difficulty in identifying the origin of these neurological findings. It is common to be misdiagnosed or delayed diagnosis due to the complicated nature. We evaluated the prevalence, distribution, and clinical characteristics of OLF, especially in patients with LCS.

Methods

The authors performed a retrospective analysis of the outcomes of 61 patients who underwent thoracic surgeries performed for symptomatic T-OLF. In all the patients, whole spine lesions were evaluated preoperatively. We examined the factors related to poor outcomes (the recovery rate of the Japanese Orthopedic Association score for thoracic myelopathy is less than 40%) following OLF surgeries. We compared the clinical outcomes according to whether there was concurrent LCS, and determined the optimal surgical approach.

Results

The occurrence of T-OLF increased with age. Forty-six cases (75.4%) were considered to be tandem T-OLF and LCS (LCS group). An advanced age, and concurrent LCS were associated with a poor outcome after the surgery. The LCS group significantly included a greater number of elderly, and more light-weighted patients with Modic change in thoracic spine and a greater sagittal vertical axis, resulting in the lower neurological recovery. Additional lumbar surgery (13cases) effectively improved both the T-JOA and L-JOA scores (from 6.5 ± 2.0 points to 8.0 ± 1.8 points, p = 0.0406, and from 14.5 ± 4.7 points to 20.7 ± 2.6 points, p = 0.001, respectively) in OLF patients with LCS.

Conclusions

T-OLF was highly associated with other spinal disorders. Poor outcomes in T-OLF surgery could be associated with age and concurrent LCS, and an additional surgery for another lumbar lesion significantly improved neurological findings in T-OLF patients.

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.

A comparison study of percutaneous endoscopic decompression and posterior decompressive laminectomy in the treatment of thoracic spinal stenosis

Background

Percutaneous endoscopic decompression (PED) is considered a minimally invasive and safe procedure in lumbar degenerative disease. Few authors report the success of PED for thoracic spinal stenosis (TSS) with thoracic myelopathy. The objective of this study was to compare the outcome of PED versus posterior decompressive laminectomy (PDL) for TSS.

Methods

We retrospectively reviewed 30 consecutive patients who underwent surgery for single-level TSS from January 1, 2015 to May 1, 2019.These patients were divided into PED (n = 16) and PDL(n = 14) group. Preoperative demographic characteristics and perioperative outcomes were reviewed. Pre- and postoperative neurological status was evaluated using the modified Japanese Orthopaedic Association (mJOA) score and the recovery rate (RR).

Results

The patients’ mean age was 57.3 years (27–76) in PED group and 58.8 years (34–77) in PDL group. No statistical difference was found between two groups with regards to neurological status at pre-operative and final follow-up. The RR in PED group achieved the same improvement as PDL group (87.5% vs 85.7%, P > 0.05), while the PED brought advantages in operative time(m) (86.4 vs 132.1, p < 0.05), blood loss (mL) (18.21 vs 228.57, p < 0.05),drainage volume(mL) (15.5 vs 601.4, p < 0.05), and hospital stay (d) (3.6 vs 5.6, p < 0.05).

Conclusions

Both PED and PDL showed favorable outcome in the treatment of TSS. Besides, PED had advantages in reducing traumatization. In terms of perioperative quality of life, PED could be an efficient supplement to traditional posterior decompressive laminectomy in patients with TSS.

One-stage posterior surgery with intraoperative ultrasound assistance for thoracic myelopathy with simultaneous ossification of the posterior longitudinal ligament and ligamentum flavum at the same segment: a minimum 5-year follow-up study

BACKGROUND CONTEXT

Ossification of the posterior longitudinal ligament (OPLL) and ligamentum flavum (OLF) are not uncommon independent causes of thoracic myelopathy (TM); however, concomitant OPLL and OLF at the same segment is rare. The ideal surgical strategy remains controversial, and it is difficult for surgeons to balance sufficient neural decompression while simultaneously reducing the occurrence of postoperative neurological defect after circumferential decompression (CD). Aiming to solve this dilemma, we investigated a CD-based surgery using intraoperative ultrasound (IOU) assistance to evaluate spinal decompression sufficiency.

PURPOSE

The aims of this study are to evaluate the surgical outcomes and identify prognostic factors of one-stage posterior surgery with IOU assistance in patients with concomitant OPLL and OLF.

STUDY DESIGN/SETTING

Retrospective study of a single-center TM database with long-term follow-up.

PATIENT SAMPLE

Twenty-four patients with TM and concomitant OPLL and OLF.

OUTCOME MEASURES

Japanese Orthopaedic Association (JOA) score system for TM, recovery rate (RR), complication rate.

METHODS

Twenty-four patients' data were retrospectively reviewed. All patients initially underwent en bloc excisions of posterior spinal canal elements, and IOU was then used to evaluate spinal decompression sufficiency. If any compression of OPLL was confirmed in IOU, further CD procedure was performed. The JOA score was used to evaluate health-related quality of life. RR was calculated using the Hirabayashi formula. A RR ≥50% was considered favorable, and a RR <50% was considered unfavorable. The paired t test was performed to statistically compare the preoperative and postoperative JOA scores. The chi-squared test, rank sum test, and logistic regression analyses were performed to find variants associated with unfavorable surgical outcomes The prognostic factors were analyzed by Spearman correlation and Pearson correlation analyses.

RESULTS

The invasive CD procedure were avoided in 9 of 28 segments were avoided, with a mean blood loss of 1,458 mL. Seventeen patients experienced cerebrospinal fluid leakage, and 5 experienced immediate postoperative paralysis. The mean JOA score improved from 4.25±2.2 (preoperative) to 8.16±1.9 (final follow-up). The mean RR was 57.7%±29.4%. There was a significant difference (p<.01) between the preoperative and final follow-up JOA score. A comparison between the favorable and the unfavorable groups showed no significant differences in the evaluated factors, but the considerable blood loss was a significant risk factor for poor RR (p=.036, b=-0.43).

CONCLUSIONS

One-stage CD-based surgery via a posterior approach with IOU assistance for the treatment of concomitant OPLL and OLF led to significant functional improvement in the majority of patients. Under the premise of sufficient decompression, the postoperative paralysis rate reduced compared to that in previous studies. However, there were still high cerebral spinal fluid leakage rates. Considerable blood loss is a risk factor for poor RR.

Spinal Epidural Lipomatosis with Osteoporotic Vertebral Fractures Presenting as Acute Thoracic Myelopathy in a 33-Year-Old Man with Cushing Disease

BACKGROUND

Steroid-related spinal epidural lipomatosis (SEL) is a well-known condition most commonly encountered in patients taking chronic steroid medications. Endogenous Cushing syndrome is a rare cause of SEL. The authors report an unusual presentation of acute thoracic myelopathy due to SEL with osteoporotic vertebral compression fractures in a patient with Cushing disease.

CASE DESCRIPTION

A 33-year-old man presented with thoracic myelopathy due to SEL and multiple vertebral compression fractures. He had Cushingoid clinical features, and investigations revealed a pituitary microadenoma as the cause of hypercortisolism. The diagnosis was missed on multiple occasions before the onset of paraparesis. The patient was treated with urgent thoracic laminoplasty followed by transsphenoidal surgery on the same day. Although normalization of the serum cortisol levels was delayed by 6 months, he had a complete neurologic recovery and remains symptom free at 2 years follow-up.

CONCLUSIONS

This is a rare presentation of Cushing disease and has been reported only twice before in the 1990s. This case highlights the need to keep a high degree of suspicion for development of thoracic myelopathy in a patient with Cushing syndrome who develops thoracic compression fractures associated with SEL. Early recognition of this clinical association and addressing the primary endocrine problem urgently could have prevented spinal cord involvement and the subsequent spine surgery. This scenario is also documented in previous published case reports of this association where the diagnosis of Cushing syndrome has been revealed retrospectively after the development of neurologic symptoms.

Surgical technique modification of circumferential decompression for thoracic spinal stenosis and clinical outcome

Progressive thoracic myelopathy caused by ossification of posterior longitudinal ligament (OPLL) responds poorly to conservative therapy. The most direct decompression is extirpation of ossified posterior longitudinal ligament (PLL). Surgical outcomes of posterior approaches to remove ossified PLL are not always satisfactory because of the risk of neurological deterioration. In this study, we modified the conventional anterior decompression technique via a posterior approach for thoracic OPLL. From an anterior approach, the posterior cortex of vertebral body was exposed and the ossified PLL was removed. Then kyphosis correction was done via posterior instrumentation to reduce cord compression between dura under tension and the anterior canal wall. From the back, the distal end of the ossified PLL was displaced anteriorly to create a gap between ossified PLL and dura, remaining adhesions were divided and the ossified PLL was manipulated through this gap under direct vision. The surgical technique was applied in 20 patients with thoracic myelopathy caused by OPLL. One case of postoperative neurological deterioration was encountered but this recovered fully. Our outcomes were relatively favorable.

A Review of Minimally Invasive Surgical Techniques for the Management of Thoracic Disc Herniations

Thoracic disc herniation (TDH) is a rare, but technically challenging, disorder. Apart from their unfamiliarity with this condition, surgeons are often posed with challenges regarding the diverse methods available to address TDH, the neurological disturbances accompanying the disorder, the prospect of iatrogenic cord damage during surgical procedures, and the complications associated with various surgical approaches. In today's era, when minimally invasive surgery has been incorporated into almost every aspect of managing spine disorders, it is necessary for surgeons to be aware of the various minimally invasive techniques available for the management of these rare and difficult conditions. In this review article, we provide a synopsis of the epidemiology, clinical features, and technical aspects of TDH, starting from level identification to intraoperative neuromonitoring and including important steps and guidance for all the minimally invasive approaches to TDH. We conclude the review by providing insights into the clinical decision-making process and outline the specific aspects of "giant" thoracic discs and indications for fusion in certain conditions. Outcomes of minimally invasive surgery for these conditions are generally favorable. The location of herniation is an important factor for surgical planning.

Percutaneous full endoscopic posterior decompression of thoracic myelopathy caused by ossification of the ligamentum flavum

PURPOSE

Ossification of ligamentum flavum (OLF) is the leading cause of progressive thoracic myelopathy (TM) in East Asian countries. Surgical decompression is the general treatment for TM. This study investigated the application of percutaneous full endoscopic posterior decompression (PEPD) for the treatment of thoracic OLF.

METHODS

Eighteen patients with TM were treated by PEPD under local anaesthesia. Patients had an average age of 59.1 years and single-level lesions mostly at the lower thoracic vertebrae. Computed tomography and magnetic resonance imaging were used to classify the OLF. The pre- and postoperative neurological statuses were evaluated using the American Spinal Injury Association (ASIA) sensory and motor score, modified Japanese Orthopaedic Association (mJOA) score and Frankel grade.

RESULTS

OLF for all patients was classed as lateral, extended, and enlarged types without comma and tram track signs. Decompression was completed, and a dome-shaped laminotomy was performed through limited laminectomy and flavectomy. Dural tears in 2 patients were the only observed complication. The average score of ASIA sensory and motor, mJOA, as well as the Frankel grade improved significantly after surgery at an average follow-up time of 17.4 months. The average recovery rate (RR) was 47.5% as calculated from the mJOA scores. According to RR, 10 cases were classified as good, 4 cases fair, and 4 cases unchanged.

CONCLUSIONS

For patients with thoracic OLF at a single level and lateral, extended, and enlarged types without comma and tram track signs, it is safe and reliable to perform PEPD, which has satisfactory clinical results. These slides can be retrieved under Electronic Supplementary Material.

Clinically significant radiographic parameter for thoracic myelopathy caused by ossification of the ligamentum flavum

PURPOSE

To investigate radiographic parameters to improve the accuracy of radiologic diagnosis for ossification of ligamentum flavum (OLF)-induced thoracic myelopathy and thereby establish a useful diagnostic method for identifying the responsible segment.

METHODS

We classified 101 patients who underwent surgical treatment for OLF-induced thoracic myelopathy as the myelopathy group and 102 patients who had incidental OLF and were hospitalized with compression fracture as the non-myelopathy group between January 2009 and December 2016. We measured the thickness of OLF (TOLF), cross-sectional area of OLF (AOLF), anteroposterior canal diameter, and the ratio of each of these parameters.

RESULTS

Most OLF cases with lateral-type axial morphology were in the non-myelopathy group and most with fused and tuberous type in the myelopathy group. Most grade-I and grade-II cases were also in the non-myelopathy group, whereas grade-IV cases were mostly observed in the myelopathy group. The AOLF ratio was found to be the best radiologic parameter. The optimal cutoff point of the AOLF ratio was 33.00%, with 87.1% sensitivity and 87.3% specificity. The AOLF ratio was significantly correlated with preoperative neurological status.

CONCLUSIONS

An AOLF ratio greater than 33% is the most accurate diagnostic indicator of OLF-induced thoracic myelopathy. In cases of multiple-segment OLF, confirmation of cord signal change on MRI and an AOLF measurement will help determine the responsible segment. AOLF measurement will also improve the accuracy of diagnosis of OLF-induced thoracic myelopathy in cases of grade III or extended-type axial morphology. These slides can be retrieved under Electronic Supplementary Material.

High thoracic ossification of ligamentum flavum causing partial Horner syndrome

We report a case of high thoracic ossification of the ligamentum flavum (OLF) causing a partial Horner's syndrome. A 57-year-old man developed a walking disorder, as well as right-sided miosis and anhidrosis. Magnetic resonance imaging demonstrated a spinal cord compressing T2-T3 OLF. The patient improved after surgery.

A thoracic extradural chordoid meningioma: a unique case report and literature review

We describe the unique case of a patient being diagnosed with a thoracic extradural chordoid meningioma following her presentation with mild lower limb pyramidal weakness and a T8 sensory level. This is the first report of an extradural chordoid meningioma being identified in the thoracic spine. The tumour was successfully resected through a posterior thoracic laminectomy approach. Post-operatively, her neurological deficit resolved and to date she has not experienced a radiological recurrence. In this report, we review the literature and discuss this unusual tumour's characteristics and prognostic significance.

Surgical outcome of thoracic myelopathy caused by ossification of ligamentum flavum

Ossification of the ligamentum flavum (OLF) may result in thoracic myelopathy (TM) because of the spinal canal narrowing. The aim of this study was to investigate clinical outcomes of symptomatic thoracic OLF treated using posterior decompressive laminectomy. We made a retrospective review of patients who underwent posterior decompressive laminectomy from 2007 through 2016 for symptomatic TM caused by OLF. Thirty-three patients who had surgery for TM caused by OLF that was diagnosed based on clinical, radiologic, and pathologic evaluations. All patients had undergone decompressive laminectomy and excision of the OLF. The clinical course was evaluated according to modified JOA scores. Magnetic resonance imaging was used to determine the number of vertebral segments demonstrating OLF, the level of thoracic cord involvement, and spine lesions coexisting with OLF. Results showed the neurological status improved at follow up (70.82±32.22months) from a preoperative mean Japanese Orthopaedic Association score of 7.03±1.29 points to 9.52±0.83 points at the last follow up (p<0.01). Recovery outcomes were excellent in 8 patients, good in 22 patients, fair in 2 patients and poor in 1 patient. Surgical complications, which resolved after appropriate and prompt treatment, including cerebrospinal fluid leakage in 4 patient, immediate postoperative neurologic deterioration in 2 patient, and wound infection in 4 patient. Our findings suggest that posterior decompressive laminectomy with or without instrumented fusion is an effective treatment for symptomatic thoracic OLF, which provides satisfactory clinical improvement.

Sacral epidural arteriovenous fistulas: imitators of spinal dural arteriovenous fistulas with different pathologic anatomy: report of three cases and review of the literature

BACKGROUND

Sacral epidural arteriovenous fistulas (eAVFs) are rare and often misdiagnosed because of the incongruence between the thoracic level of clinical deficits and the sacral location of the offending pathology. Failure to diagnose this lesion delays treatment, resulting in prolonged venous hypertension in the cord, progressive neurological deterioration, and decreased chances of recovery.

METHODS

A single-institution case series and the published literature were reviewed.

RESULTS

Three patients had sacral eAVFs are located in the ventral epidural space with outflow connections to radicular veins that arterialized spinal cord veins, all presenting with thoracic myelopathy, venous engorgement, and delayed diagnosis. All eAVFs were occluded completely with radiographic and clinical improvement.

CONCLUSIONS

Sacral eAVF pathophysiology, namely venous hypertension and compromised spinal cord circulation, is exactly the same as dural AVFs, as is their treatment: the interruption of outflow by occlusion of the draining vein, which effectively eliminates venous hypertension, without occlusion of the actual fistula itself. Epidural exposure of sacral eAVFs is not necessary, whereas complete intradural occlusion of their radicular drainage is. Draining radicular veins intermingle with the nerve roots and their occasional multiplicity makes them more difficult to identify intraoperatively.

Surgical management of thoracic idiopathic spinal cord herniation. Technical case report and review

Idiopathic spinal cord herniation (ISCH) is a rare spinal disease, in which chronic cerebrospinal fluid pulsations push the arachnoid and adjacent thoracic spinal cord region through an antero-lateral dural defect of congenital, post-traumatic, or inflammatory/erosive origin. Symptomatic patients commonly present around the 5th decade of life with slowly progressive myelopathy. Diagnosis relies on high-resolution magnetic resonance imaging. Stable mild cases may be observed, whereas in progressive symptomatic situations, surgical spinal cord reposition and dural defect repair with a dural patch is the preferred treatment. We present a case of ISCH at T5/6 and a review the literature.

Risk factors and outcomes in thoracic stenosis with myelopathy: A single center experience

OBJECTIVE

Identify risk factors predisposing to thoracic spinal stenosis and myelopathy (TS) and address treatment options and outcomes.

METHODS

A retrospective review of our center's experience with TS over 10 years. Clinical and magnetic resonance imaging (MRI) data, surgical intervention and outcomes using Frankel and Japanese Orthopedic Association (JOA) scales were collected.

RESULTS

A total of 44 patients with TS were identified. There were 30 men and 14 women with a mean age±SD of 66±15years. Neurological performance was evaluated using the Frankel scale (A-E or 1-5), and JOA scale for myelopathy (0-11). Frankel scores (1-5) and JOA scores (0-11) on admission were 3.5±0.9 and 6.8±2.6 respectively. At follow-up, Frankel scores had improved to 4.1±0.8 (p=0.041) and JOA scores had improved to 8.3±2.4 (p=0.021). The presence on admission of increased signal from the cord on T2-weighted MRI was associated with lower Frankel and JOA scores (3.3±0.9, and 6.2±2.5 respectively) than in those with absent increased signal (4.0±0.4 and 8.6±2.1, p=0.02 and p=0.008 respectively). There were 4 complications, requiring exploration and debridement for dehiscence in 3 and an epidural hematoma in the fourth that necessitated evacuation, with a good outcome. A fifth patient underwent reoperation at the same level 18 months later for persistent stenosis.

CONCLUSION

Thoracic stenosis with myelopathy should be entertained in patients with myelopathy. Over half of our patients with TS were over the age of 70, and men outnumbered women by a ratio of 2:1. Nearly half the patients with TS had concomitant cervical and/or lumbar degenerative disease warranting surgery also. Increased signal intensity on T2-weighted MRI images correlated with lower Frankel and JOA scores compared to those without. Decompression for thoracic stenosis is associated with neurological improvement.

Clinical outcomes after decompressive laminectomy for symptomatic ossification of ligamentum flavum at the thoracic spine

Ossification of the ligamentum flavum (OLF) is a rare disease that causes acquired thoracic spinal canal stenosis and thoracic myelopathy. The aim of this study was to investigate clinical outcomes of symptomatic thoracic OLF treated using posterior decompressive laminectomy. We retrospectively analyzed the medical records of 22 patients who underwent posterior decompressive laminectomy for symptomatic thoracic OLF. The surgical results were evaluated using the modified Japanese Orthopaedic Association (JOA) scoring system and Hirabayashi recovery rate. The intensity of pain was evaluated using a visual analog scale (VAS). The mean duration of follow-up was 35.6months. The mean JOA score was significantly improved at final follow-up (9.18±standard deviation of 1.53 points [range, 6-11 points]) compared with before surgery (5.64±2.04 points [range, 3-9 points]) (P<0.001). The mean Hirabayashi recovery rate was 65.49% (range, 20-100%). Recovery outcomes were excellent in nine patients, good in eight patients, fair in four patients and unchanged in one patient. No patient was classified as deteriorated. The VAS scores were 2.82±3.08 before surgery and 0.59±1.05 at final follow-up (P=0.001). Surgical complications, which resolved after appropriate and prompt treatment, included dural tear in five patients, cerebrospinal fluid leakage in one patient, immediate postoperative neurologic deterioration in one patient, epidural hematoma in one patient, and wound infection in one patient. Our findings suggest that posterior decompressive laminectomy is an effective treatment for symptomatic thoracic OLF and provides satisfactory clinical improvement, but surgery for thoracic OLF is associated with a relatively high incidence of complications.

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.

Microendoscopic posterior decompression for the treatment of thoracic myelopathy caused by ossification of the ligamentum flavum: a technical report

PURPOSE

Ossification of the ligamentum flavum (OLF) is a common cause of progressive thoracic myelopathy in East Asia. Good surgical results are expected for patients who already show myelopathy. Surgical decompression using a posterior approach is commonly used to treat OLF. This study investigated the use of microendoscopic posterior decompression for the treatment of thoracic OLF.

METHODS

Microendoscopic posterior decompression was performed on 9 patients with myelopathy. Patients had a mean age of 59.8 years and single-level involvement, mostly at the T10-11 and T11-12 vertebrae. Computed tomography and magnetic resonance imaging were used to classify the OLF. A tubular retractor and endoscopic system were used for microendoscopic posterior decompression. Midline and unilateral paramedian approaches were performed in 2 and 7 patients, respectively. Intraoperative motor evoked potentials (MEPs) of 7 patients were monitored. Pre- and postoperative neurological status was evaluated using the modified Japanese Orthopaedic Association (mJOA) score.

RESULTS

Thoracic OLF for all patients were classed as bilateral type with a round morphology. Improvement of MEPs at least one muscle area was recorded in all patients following posterior decompression. A dural tear in one patient was the only observed complication. The mean recovery rate was 44.9 %, as calculated from mJOA scores at a mean follow-up period of 20 months.

CONCLUSIONS

Microendoscopic posterior decompression combined with MEP monitoring can be used to treat patients with thoracic OLF. The optimal surgical indication is OLF at a single vertebral level and of a unilateral or bilateral nature, without comma and tram track signs, and a round morphology.

A radical procedure of circumferential spinal cord decompression through a modified posterior approach for thoracic myelopathy caused by severely impinging anterior ossification

BACKGROUND CONTEXT

Thoracic myelopathy caused by an anterior, massive ossified plaque is often progressive and responds poorly to conservative treatment. Direct removal of the compressing ossification is the optimal procedure for a spinal cord that is severely impinged anteriorly. However, both anterior and posterior decompressive manipulations have caused catastrophic iatrogenic spinal cord injuries. A comprehensive treatment method for severe thoracic myelopathy that enables a sufficient and safe decompression of the spinal cord is needed.

PURPOSE

The purpose of this study is to demonstrate the efficacy, safety, and results of a one-stage circumferential decompressive procedure using a modified posterior approach in patients with severe thoracic myelopathy resulting from anterior spinal compression.

STUDY DESIGN

A modified procedure of circumferential spinal cord decompression for thoracic myelopathy is described. A retrospective study was conducted to investigate the clinical outcomes of 23 sequentially treated patients.

PATIENT SAMPLE

Twenty-three patients were treated sequentially with a modified procedure for circumferential spinal cord decompression for thoracic myelopathy.

OUTCOME MEASURES

Outcomes were assessed using the Japanese Orthopedic Association (JOA) score, modified Frankel classification, Hirabayashi recovery rate, and a general assessment of complications.

METHODS

Twenty-three patients with thoracic myelopathy caused by a massive, anterior ossified structure were treated with an extensive posterior laminectomy, anterior removal of the ossification, and interbody fusion with kyphosis-reversing stabilization through a modified posterolateral approach. The neurologic outcomes are evaluated according to the JOA and the modified Frankel classification before surgery, 2 weeks after surgery, 1 year after surgery, and at the final follow-up visit. The surgical outcomes are also described using the Hirabayashi recovery rate. Radiographs, computed tomography (CT), and magnetic resonance imaging were performed before and after surgery. A postoperative CT scan was obtained to determine the efficacy of the decompression. Operative time, intraoperative blood loss, and complications were reviewed from the medical records. In addition, a 48-year-old man who presented with severe thoracic myelopathy resulting from anterior impingement with multiple osteophytes is described as an illustrative patient.

RESULTS

The sites of ossification in this series were distributed widely, from T4-T12. The anterior ossified plaques of all patients were resected completely. Five patients who had intraoperative evidence of dural ossification required resection of the ossified dura matter. The average operating time was 276 minutes. Mean intraoperative blood loss was 1,350 mL. The postoperative follow-up ranged from 2.5 to 6 years, with an average of 4.6 years. The average preoperative JOA score was 4.3±1.5 points, and it improved to 6.1±1.9 points 2 weeks postoperatively, to 8.1±1.8 points 1 year postoperatively, and to 8.5±1.9 points at the most recent follow-up. The overall Hirabayashi recovery rate at the final examination averaged 63.6±22.4%. Eight patients were graded as excellent, 10 as good, 4 as fair, and 1 as unchanged. No patient was graded as deteriorated. The paralysis improved by at least 1 grade in 22 patients (95.7%). Transient deterioration of thoracic myelopathy occurred immediately after surgery in three patients (13%). Cerebrospinal fluid leakage occurred in six patients (26.1%). One patient sustained severe bilateral groin pain, three had unilateral intercostal neuralgia, and pleura tear occurred in one patient.

CONCLUSION

One-stage posterior decompression, anterior extirpation of the ossification, and interbody fusion with instrumentation via a modified posterior approach is a safe and effective treatment for severe thoracic myelopathy resulting from prominent anterior impingement. This procedure is technically demanding, and the indications are limited to thoracic myelopathy caused by severe anterior impingement of various etiologies from T4-T12.

Clinical features and surgical outcomes of patients with thoracic myelopathy caused by multilevel ossification of the ligamentum flavum

BACKGROUND CONTEXT

Thoracic myelopathy caused by multilevel (three or more levels) ossification of the ligamentum flavum (OLF) is rare. Little is known about its clinical features, and the surgical outcomes along with its related factors are also unclear.

PURPOSE

To describe the clinical features, assess the safety and effectiveness of surgical decompression, and determine the prognostic factors relevant for patients with thoracic myelopathy caused by multilevel OLF.

STUDY DESIGN/SETTING

A retrospective clinical study.

PATIENT SAMPLE

Seventy-five consecutive multilevel OLF patients who underwent surgical decompression were analyzed.

OUTCOME MEASURES

Modified Japanese Orthopedic Association (JOA) scale and the recovery rate.

METHODS

Patients who underwent surgical decompression for symptomatic multilevel OLF during January 1996 to June 2010 were all included. Clinical data were collected from medical and operative records; patients were evaluated by using the JOA scale preoperatively and during the follow-up. Correlations between the surgical outcome and various factors were also analyzed.

RESULTS

Forty-three men and 32 women with a mean age of 54.7 years (range 36-78 years) were included. The mean number of involved levels is 4.6 and contiguous OLF presented in 73.3% of these patients. The most common involved levels were T10/T11 (15.4%), T9/T10 (13.3%), and T11/T12 (12.5%). Coexisting spinal disorders were found in 41 patients (54.7%). Preoperative evaluation showed the mean JOA score was 5.8±1.7; 37.3% of these patients had mild myelopathy, 53.3% had moderate myelopathy, and 9.3% had severe myelopathy. All patients received posterior laminectomy. The JOA score (mean 8.2±2.1) significantly increased postoperatively (p<.05), and multiple regression analysis showed that preoperative duration of symptoms and preoperative JOA score were important predictors of surgical outcome.

CONCLUSIONS

Laminectomy with partially internal fixation is safe and effective in treatment of patients with symptomatic multilevel OLF. The results of our study show that preoperative JOA score and preoperative duration of symptoms were important predictors for the clinical outcome.

Variables affecting postsurgical prognosis of thoracic myelopathy caused by ossification of the ligamentum flavum

BACKGROUND CONTEXT

Ossification of the ligamentum flavum (OLF) may result in thoracic myelopathy (TM) because of narrowing of the spinal canal. Because symptoms vary and are subjective, diagnosis of TM caused by OLF is sometimes difficult when based on symptoms and physical examination. Posterior decompression is indicated in patients with TM caused by OLF because it is believed that surgery is the most effective treatment. However, surgical outcomes vary. We are unaware of reports of objective presurgical diagnostic parameters, such as neurologic and radiologic findings, relating to the postsurgical prognosis in patients with TM caused by OLF.

PURPOSE

To determine which presurgical and surgical variables were most closely related to postsurgical prognosis of TM caused by OLF.

STUDY DESIGN

Retrospective review of the records of the cohort of patients who had undergone surgery from 1988 through 2008 at the University of Toyama Hospital for TM caused by OLF.

PATIENT SAMPLE

Forty-one patients who had surgery for TM caused by OLF that was progressive, severe, or both and for which the diagnosis was based on clinical, radiologic, and pathologic evaluations.

OUTCOME MEASURES

Relationship between the highest follow-up Japanese Orthopaedic Association (JOA) score for neurologic evaluation and of Hirabayashi's formula to indicate the extent of normalization after surgery with respect to the following 10 variables: age at surgery; sex; duration of presurgical symptoms; complications of diabetes mellitus; complications of hypertension; presence of presurgical hyperreflexia in either or both of the patellar tendon reflex and the Achilles tendon reflex; presurgical impairment of joint position sense in the big toes; number of levels affected by OLF; concurrent spinal lesions including ossification of the posterior longitudinal ligament; and intramedullary change of the spinal cord seen on magnetic resonance imaging (MRI).

METHODS

Multiple linear analyses were used to evaluate the variables related to postsurgical recovery.

RESULTS

Presurgical impairment of joint position sense in the big toe was the most important predictor of the highest postsurgical JOA score and of the highest percentage recovery rate. The number of affected OLF levels also predicted the postsurgical highest JOA score, but not statistically significantly so. Age at surgery, sex, and duration of symptoms presurgically did not affect postsurgical recovery. Complications of diabetes mellitus or of hypertension did not affect percentage recovery rate. The difference between recovery rate in patients with or without concurrent spinal lesions was not significant. Presurgical hyperreflexia was not correlated with recovery. Postsurgical JOA scores and percentage recovery rates of scores in patients whose presurgical MRIs had shown intramedullary signal change were not statistically significantly different from those whose MRIs had not shown signal change.

CONCLUSIONS

An excellent postoperative prognosis is not always possible in patients with TM caused by OLF. It may be important to check for impairment of joint position sense in the big toe, the number of levels affected by OLF, and presurgical intramedullary signal change on MRI before continuing to surgery.

Upper thoracic myelopathy caused by delayed neck extensor weakness in myotonic dystrophy

Myotonic dystrophy is the most common autosomal dominant myopathy in adults. Our patient, a 41 year-old female suffering from myotonic muscular dystrophy, developed upper thoracic myelopathy due to hypertrophy of the ligamentum flavum and the posterior longitudinal ligament. She had a typical hatchet face and ptosis with "head hanging forward" appearance caused by neck weakness. Motor weakness, sensory changes and severe pain below T4 level, along with urinary incontinence began 3 months ago. Genetic and electrodiagnostic studies revealed myotonic dystrophy type 1. Magnetic resonance imaging of the spine showed loss of cervical lordosis and spinal cord compression due to hypertrophied ligamentum flavum and posterior longitudinal ligament at T1 to T3 level. We concluded that her upper thoracic myelopathy was likely related to the thickness of the ligamentum flavum and posterior longitudinal ligament due to repetitive mechanical stress on her neck caused by neck muscle weakness with myotonic dystrophy.

Thoracic myelopathy caused by ossification of the ligamentum flavum

OBJECTIVE

Ossification of the ligamentum flavum (OLF) is a rare cause of thoracic myelopathy. The aim of this study was to identify factors associated with the surgical outcome on the basis of preoperative clinical and radiological findings.

METHODS

Data obtained in 26 patients whot underwent posterior decompression for thoracic myelopathy, caused by thoracic OLF, were analyzed retrospectively. Patient age, duration of symptoms, OLF type, preoperative and postoperative neurological status using the Japanese Orthopedic Association (JOA) scoring system, surgical outcome, and other factors were reviewed. We compared the various factors and postoperative prognosis. All patients had undergone decompressive laminectomy and excision of the OLF.

RESULTS

Using the JOA score, the functional improvement was excellent in 8 patients, good in 14, fair in 2, and unchanged in 2. A mean preoperative JOA score of 6.65 improved to 8.17 after an average of 27.3 months. According to our analysis, age, gender, duration of symptoms, the involved spinal level, coexisting spinal disorders, associated trauma, intramedullary signal change, and dural adhesions were not related to the surgical outcome. However, the preoperative JOA score and type of OLF were the most important predictors of the surgical outcome.

CONCLUSION

Early diagnosis and sufficient surgical decompression could improve the functional prognosis for thoracic OLF. The postoperative results were found to be significantly associated with the preoperative severity of myelopathy and type of OLF.