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

Diagnosis and Management of Thoracic Myelopathy

Thoracic myelopathy can be a challenging condition to diagnose and treat. Successful outcomes depend on early recondition of the pathology and appropriate surgical referral in cases of progressive neurologic deterioration. The thoracic cord is tethered in kyphosis by the dentate ligaments and contains a tenuous blood supply. These conditions make the thoracic cord particularly susceptible to external compression and ischemic damage. Careful preoperative planning with specific attention to the location and source of thoracic stenosis is critical to successful decompression and complication avoidance. The purpose of this discussion is to outline the common sources of thoracic myelopathy and current recommendations regarding diagnosis and management. The review concludes with an overview of the most up-to-date literature regarding clinical outcomes.

Unilateral biportal endoscopic surgical decompression for symptomatic ossification of the ligamentum flavum - Is it enough to improve the clinical outcome? A case-control study

Purpose

Open decompression is currently the standard surgical procedure for symptomatic OLF. As the minimal invasive method gains popularity, UBE is considered a reliable technique with less complication. However, the outcome is still in question. This study aimed to evaluate and compare UBE versus open surgery in symptomatic OLF cases.

Methods

We evaluated 35 patients with single- or two-level thoracic OLF, underwent decompression by open or UBE. Surgery duration, estimated blood loss, and LOS were recorded as intraoperative parameters. Minimum follow-up was 1 year to evaluate clinical parameters based on the mJOA score, Frankel grade, and recovery rate (RR).

Results

The UBE procedure showed significant superiority with faster surgery (62.5 min vs. 180 min; p < 0.001), less blood loss (50 mL vs. 250 mL; p < 0.001), and shorter LOS (4 days vs. 6 days; p < 0,001). UBE patients showed notable clinical improvement on the mJOA score at 1 year (8.2 ± 0.18 vs. 6.8 ± 0.24; p = 0.015). Frankel grade improvements seen in both groups with 51.4% of subjects having at least a 1-point upgrade. RR in 1 year resulted in significant recovery in UBE group (RR-UBE 43.2 ± 17 vs. RR-open 26.3 ± 15.3; p < 0.05). No neurological deterioration or significant complication occurred after either procedure.

Conclusion

The UBE technique allows faster decompression with less blood loss and shorter LOS compared to open surgery. It was found to be a reliable treatment option in treating OLF with favorable clinical outcomes and improved patient neurological status.

Early Recurrence of Thoracic Ossification of the Ligamentum Flavum After Posterior Decompression Surgery: A Case Report

Thoracic ossification of the ligamentum flavum (OLF) is known to result in spinal canal stenosis and myelopathy. It is typically treated through decompressive laminectomy and resection of the ossified ligament, which is known to improve neurological deficits. However, the recurrence of OLF post-surgery remains a relatively undocumented and complex issue. The present report describes the case of a 58-year-old male patient who had obesity (BMI 34), diabetes mellitus, and Basedow's disease. The patient presented with bilateral lower limb paresthesia and associated gait impairment, resulting in an urgent hospital admission. Imaging diagnostics identified extensive thoracic ossification of the posterior longitudinal ligament and OLF, both of which resulted in significant spinal cord compression. He underwent posterior decompression with instrumented fusion from T1 to T9 and additional laminectomy and OLF resection at T10/11. Despite an initial improvement in the postoperative period, the patient developed an epidural hematoma one week following surgery, causing significant paralysis of the lower limbs. This complication was promptly addressed with hematoma removal surgery. Six months after the initial procedure, his walking function improved significantly, but eight months after surgery, he experienced a sudden regression in motor functions due to the recurrence of OLF at T10/11, necessitating an additional posterior instrumented fusion surgery. Subsequent to the additional surgical procedure, the patient experienced an amelioration in paralysis, enabling him to ambulate with the aid of a cane. The recurrence of thoracic OLF after decompression surgery is a significant concern, especially in cases where decompression without instrumented fusion is performed. When determining the surgical procedure for thoracic OLF in cases with extensive ossification of the spinal ligaments, it is crucial to consider the degree of spontaneous fusion and mobility of the spinal segments, as demonstrated in the present case. The concentration of mechanical stress due to fusion at adjacent segments and intervertebral mobility at the thoracolumbar junction may increase the risk of OLF recurrence and should be carefully assessed preoperatively, even though posterior decompression surgery is typically considered a sufficient option for thoracic OLF.

Distinctive Characteristics of Thoracolumbar Junction Region Stenosis

STUDY DESIGN

Retrospective case series and systemic literature meta-analysis.

BACKGROUND

Thoracolumbar junction region stenosis produces spinal cord compression just above the conus and may manifest with symptoms that are not typical of either thoracic myelopathy or neurogenic claudication from lumbar stenosis.

OBJECTIVE

As few studies describe its specific pattern of presenting symptoms and neurological deficits, this investigation was designed to improve understanding of this pathology.

METHODS

A retrospective review assessed surgically treated cases of T10-L1 degenerative stenosis. Clinical outcomes were evaluated with the thoracic Japanese Orthopedic Association score. In addition, a systematic review and meta-analysis was performed in accordance with guidelines provided by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA).

RESULTS

Of 1069 patients undergoing laminectomy at 1477 levels, 31 patients (16M/15F) were treated at T10-L1 a mean age 64.4 (SD=11.8). Patients complained of lower extremity numbness in 29/31 (94%), urinary dysfunction 11/31 (35%), and back pain 11/31 (35%). All complained about gait difficulty and objective motor deficits were detected in 24 of 31 (77%). Weakness was most often seen in foot dorsiflexion 22/31 (71%). Deep tendon reflexes were increased in 10 (32%), decreased in 11 (35%), and normal 10 (32%); the Babinski sign was present 8/31 (26%). Mean thoracic Japanese Orthopedic Association scores improved from 6.4 (SD=1.8) to 8.4 (SD=1.8) ( P <0.00001). Gait subjectively improved in 27/31 (87%) numbness improved in 26/30 (87%); but urinary function improved in only 4/11 (45%).

CONCLUSIONS

Thoracolumbar junction stenosis produces distinctive neurological findings characterized by lower extremity numbness, weakness particularly in foot dorsiflexion, urinary dysfunction, and inconsistent reflex changes, a neurological pattern stemming from epiconus level compression and the myelomeres for the L5 roots. Surgery results in significant clinical improvement, with numbness and gait improving more than urinary dysfunction. Many patients with thoracolumbar junction stenosis are initially misdiagnosed as being symptomatic from lumbar stenosis, thus delaying definitive surgery.

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.

Preoperative Magnetic Resonance Imaging Signal Intensity Classification Is Associated With Clinical Presentation and Surgical Outcomes in Myelopathy Caused by Thoracic Ossification of Ligamentum Flavum: A Multicenter Study

STUDY DESIGN

Retrospective Cohort Study.

OBJECTIVES

To explore whether classification of the increased signal intensity (ISI) on magnetic resonance imaging (MRI) correlates with clinical presentations and outcomes in symptomatic thoracic ossification of ligamentum flavum (T-OLF) patients.

METHODS

All patients with symptomatic T-OLF who underwent laminectomy at four institutions were reviewed. The ISI on preoperative T2-weighted MRI was divided into 3 groups, Grade 0, none; Grade 1, light (obscure); and Grade 2, intense (bright). Neurological function before surgery and at follow-up was evaluated by the revised Japanese Orthopedic Association (JOA) score. Patients' demographics, clinical manifestations, and surgical outcomes were compared.

RESULTS

A total of 94 patients were involved. Preoperative MRI showed 32 patients in Grade 0, 39 patients in Grade 1, and 23 patients in Grade 2. Low extremities numbness, weakness, and clinical signs were less frequent in Grade 0 patients. The grade of ISI was correlated with the duration of symptoms and cord compression. Grade 0 patients had a better preoperative JOA score than those with ISI changes, while Grade 2 patients showed worse neurological recovery, longer duration of operation, more intraoperative blood loss, and a higher incidence of perioperative complications.

CONCLUSION

The classification of ISI is an effective parameter for preoperatively assessing cord compression, clinical severity, and surgical outcomes in T-OLF patients. Grade 0 patients have relatively mild neurological impairment but are more likely to be misdiagnosed. Grade 2 indicates the worst clinical impairment and neurological recovery, and implies a risky and challenging surgery.

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.

The Gantry Crane Technique: A Novel Technique for Treating Severe Thoracic Spinal Stenosis and Myelopathy Caused by Ossification of the Ligamentum Flavum and Preliminary Clinical Results

STUDY DESIGN

Retrospective single-arm study.

OBJECTIVE

To propose a novel technique named the gantry crane technique for treating severe thoracic spinal stenosis and myelopathy caused by thoracic ossification of the ligamentum flavum (TOLF) and investigate its clinical results.

METHODS

From June 2017 to January 2019, 18 patients presenting with severe spinal stenosis and myelopathy caused by TOLF were included in our study. All patients were treated with gantry crane technique, pre-operative JOA score, as well as 3 days-, 3 months-, 6 months-, 12 months-, 24 months after operation, and Hirabayashi recovery rate were reported. Pre- and post-operative image were utilized for the assessment of post-operative effect. Peri-operative complications were recorded to assess the safety of the gantry crane technique.

RESULTS

The JOA score increased from 10.56 ± 3.76 preoperatively to 12.94 ± 3.33, 13.56 ± 3.48, 13.94 ± 3.32, 14.17 ± 3.70 and 14.06 ± 3.54 in 3 days, 3 months, 6 months, 12 months and 24 months after surgery, respectively. The post-operative JOA scores were improved with statistical significance at the level of P < 0.05. The recovery rate was (39.09 ± 33.85) %, (51.35 ± 42.60) %, (55.79 ± 36.10) %, (64.98 ± 29.24) % and (60.98 ± 35.96) % for 3 days, 3 months, 6 months, 12 months and 24 months after surgery, respectively. There were 2 cases of SSI (surgical site infection), 1 case of NI (neurovascular injury) and 1 case of cerebrospinal fluid (CSF) leakage.

CONCLUSIONS

This study highlights a safe and effective technique, the gantry crane technique, for treating severe thoracic spinal stenosis and myelopathy caused by TOLF.

Comparison of Surgical Results of the Bridge Crane Technique Versus Laminectomy for the Treatment of Thoracic Myelopathy Caused by Ossification of the Ligamentum Flavum

STUDY DESIGN

A retrospective study.

OBJECTIVES

This study aimed to evaluate the safety and effectiveness of the bridge crane technique versus laminectomy for the treatment of thoracic myelopathy caused by ossification of the ligamentum flavum (OLF).

METHODS

Totally 41 patients who underwent surgical decompression due to thoracic OLF from May 2017 to June 2018 in our institution were enrolled in this study and were divided into group BG (bridge crane technique, n = 19) and group L (laminoectomy, n = 22). Demographic data was collected from medical records and the modified Japanese Orthopaedic Association (JOA) scoring system was used to evaluate the neurological outcomes during the follow-up. Surgery-related complications were analyzed.

RESULTS

The mean duration of follow-up was comparable between group BG (19.4 ± 1.5 months) and group L (19.6 ± 1.4 months). No statistical differences were observed between two groups in terms of gender, age, duration of symptoms, preoperative occupying rate, involved levels, operation time, intraoperative blood loss, and complications. The JOA score significantly increased at the final follow-up in both groups. However, patients in group BG had higher JOA score and recovery rate (P < 0.05). Four patients in group L experienced complications, including 3 cerebrospinal fluid (CSF) leakage and one postoperative hematoma. Only one patient in group BG had CSF leakage.

CONCLUSION

The results of this study suggested that bridge crane technique may be relatively safe and effective for patients with symptomatic thoracic OLF with more satisfactory clinical improvement. However, high-quality studies are still required to validate the results of this study.

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.

Intraoperative neurophysiologic monitoring alteration during en bloc laminectomy surgery for thoracic ossification of ligamentum flavum

Background

There is real risk during en bloc resection for the treatment of thoracic ossification of ligamentum flavum (TOLF). Intraoperative neurophysiologic monitoring (IONM) has been applied to monitor neurologic functional integration of the spinal cord during surgery. However, the IONM outcome and its relationship with clinical results still needs to be investigated. The purpose of this study is to evaluate the effectiveness and usefulness of IONM in en bloc laminectomy for TOLF.

Methods

Data from a total of 68 patients with TOLF who received en bloc resection was collected for this retrospective study. IONM of somatosensory-evoked potentials (SSEPs) and motor-evoked potentials (MEPs) were analyzed in different patterns of signal alerts, i.e. alert in either MEPs or SSEPs, alert in both MEPs and SSEPs, permanent alert, or recovery during surgery. Postoperative motor and sensory neurological function was evaluated in each patient immediately after surgery and at 12-month follow-up after surgery. The relationship of IONM outcomes and postoperative neurologic function were observed.

Results

Fifty of 68 patients did not present significant changes over alert criteria of IONM, neither SSEPs nor MEPs. Those 50 patients without IONM alerts did not show post-operative neurologic deterioration. Four patients presented alert of IONM in a single modality, while 2 patients showed only SSEP alert and 2 patients showed only MEP alert. Fourteen patients showed alerts in both SSEP and MEP, while 8 patients showed one or both signals return to normal during surgery and other 6 showed permanent abnormal electrophysiologic signals to the end of surgery. In the follow-up neurologic test, 3 patients presented transient neurologic complications from among 8 patients with both SSEP and MEP alerts and recovery during surgery. Six patients without recovery of IONM showed permanent neurologic complications after surgery.

Conclusions

Results of this study prove the effectiveness and usefulness of IONM in in en bloc laminectomy surgery for TOLF. The patterns of IONM changes correlated with postoperative neurologic functions. Special attention must be paid to the rapid loss of IONM without recovery during spinal decompression.

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.

Ossified Ligamentum Flavum: Epidemiology, Treatment, and Outcomes

Ossification of the ligamentum flavum (OLF) is an uncommon but potentially serious spinal condition which can cause progressive compression of the spinal canal with associated devastating neurologic compromise. Although debate exists regarding the exact etiology of OLF, overexpression of genes and transcription factors centered around the Notch and Wnt signaling pathways because of increased mechanical stress seems to be related. There are many clinical and radiographic presentations of OLF; however, progressive myelopathy is the most commonly encountered. Radiographic analysis may reveal isolated OLF or OLF combined with ossification of other areas of the spine, such as disk, posterior longitudinal ligament, and dura. When surgery is necessary for OLF, several surgical strategies exist including open laminectomy with excision, endoscopic decompression, Bridge Crane resection, en block resection, and combined anterior and posterior approaches. Resection may be complicated by dural adhesion or dural ossification, and postoperative neurologic deficits are not uncommon.

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.

The role of cerebrospinal fluid cross-section area ratio in the prediction of dural ossification and clinical outcomes in patients with thoracic ossification of ligamentum flavum

Background

It is imperative to preoperatively distinguish dural ossification (DO) and thus anticipate the risks and outcome of the surgery for patients with ossification of ligamentum flavum (OLF). However, studies have disagreed as to the efficacy of the radiographic signs or factors to predict DO and surgical outcome. In additon, the association between the cerebrospinal fluid cross-section area ratio (CCAR) and DO or clinical outcome had not been reported. The purpose of this study was to analyse CCAR and its role in prediction of DO and neurological function recovery rate in patients with OLF.

Methods

Fifty-two consecutive patients with OLF, who underwent posterior thoracic decompression and fusion between September 2012 and March 2019 at a single institution, were retrospectively reviewed. Demographic data, radiographic signs of DO, CCAR, pre- and postoperative modified Japanese Orthopedic Association (mJOA) score were recorded.

Results

There were 27 patients in the DO group and 25 patients in the non-DO group, with a mean age at surgery of 57.4 years and 53.9 years, respectively. No significant differences were found in sex, age, segment of maximum compression and preoperative mJOA score between the two groups. The receiver operating characteristic curve showed that the value of CCAR had a relatively high value for diagnosis of DO and prediction of neurological function recovery rate (P = .000). According to the value of CCAR, three zones were defined as DO zone (≤14.3%), non-DO zone (≥44.5%), and gray zone (14.3 to 44.5%). When the value of CCAR≤14.3%, the recovery rate was poor or fair, while it had good or excellent recovery when CCAR≥45.2%.

Conclusion

The value of CCAR had a high diagnostic value for prediction of DO and neurological function recovery rate in patients with OLF.

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.

Comparing Thoracic Extensive Laminoplasty (TELP) and Laminectomy in Treating Severe Thoracic Ligamentum Flavum Ossification: A Proposed Novel Technique and Case-Control Study

Objective

(1) To propose a novel technique named thoracic extensive laminoplasty (TELP) in curing severe thoracic ligamentum flavum ossification (STOLF) and (2) to compare outcomes between TELP and laminectomy in curing STOLF.

Methods

Cases with fused or tuberous STOLF (Sato classification) treated from Jan 2015 to Jan 2017 were reviewed and divided into the TELP group (G1) and laminectomy group (G2) according to their surgical management. Data on demographics, complications, pre- and postoperative symptoms, residual spinal canal area (RSCA-1), residual spinal cord area (RSCA-2), modified Japanese Orthopedic Association score (mJOA), and health-related quality of life (HRQOL, based on the SF-36) were collected.

Results

Fifty-nine G1 and sixty-two G2 patients were enrolled. No significant differences in demographic data or preoperative data of RSCA-1, RSCA-2, mJOA, or HRQOL were observed between the two groups (p > 0.05). Patients in G1 and G2 showed similar postoperative improvements in RSCA-1 and RSCA-2 at the final follow-up (p > 0.05). However, patients in G1 showed higher postoperative improvements in mJOA (OR = 2.706, 95% CI: 1.279~5.727, p = 0.008) at the final follow-up. Patients in G1 also showed higher postoperative improvements in HRQOL than patients in G2 (p < 0.05) at the final follow-up, and patients with more severe STOLF presented with better improvements in HRQOL in G1 (p < 0.05). Dural laceration and cerebrospinal fluid leakage were observed in seven G2 patients, and no complications were found in G1 patients after surgery.

Conclusion

TELP is a novel, effective, and safer surgical technique in treating STOLF and could be a substitute for traditional laminectomy.

A systematic review of surgical procedures on thoracic myelopathy

Purpose

The surgical treatment of thoracic myelopathy is still controversial and also a challenge for spine surgeons. Therefore, the objective of this study was to review the related literature on the surgical treatment of thoracic myelopathy and try to define treatment guidelines for spine surgeons on thoracic myelopathy.

Methods

Relevant literatures were searched based on the PubMed, EMBASE, and Cochrane Library between January 2008 and December 2018. Some data on the characteristics of patients were extracted, including number of patients, mean age, surgical procedures, blood loss, complications, and pre-/post-operation modified JOA score. Recovery rate was used to assess the effect of surgery outcome, and the safety was evaluated by blood loss and incidence of complications.

Results

Thirty-five studies met the inclusion criteria and were retrieved. A total of 2183 patients were included in our systematic review, with the average age of 55.2 years. There were 69.8% patients diagnosed as ossification of ligamentum flavum (OLF), 20.0% as ossification of posterior longitudinal ligament (OPLL), 9.3% as disk herniation (DH), and 0.9% as others including diffuse idiopathic skeletal hyperostosis (DISH) and ankylosing spondylitis (AS). The volume of blood loss was more in the treatment of circumferential decompression (CD) than posterior decompression (PD), and the incidence of complications was higher in CD (P < 0.05). The volume of blood loss in minimally invasive surgery (MIS) was lowest and the incidence of complications was 19.2%. Post-operation recovery rate was 0.49 in PD, 0.35 in CD, and 0.29 in MIS while the recovery rate was 0.54 in PD, 0.55 in CD, and 0.49 in MIS at the last follow-up. When focusing on the OLF specifically, incidence of complications in PD was much lower than CD, with less blood loss and higher recovery rate. Focusing on the OPLL specifically, incidence of complications in PD was much lower than CD, with less blood loss while there was no statistical difference in recovery rate between these two methods.

Conclusions

This systematic review showed that posterior decompression for thoracic myelopathy is safer and better than circumferential decompression according to the complication rate and surgical outcome. And we should also consider the location of compression before the operation.

Bilateral translaminar osseous-channel assisted percutaneous full-endoscopic ligamentectomy decompression for thoracic myelopathy due to ossification of the ligamentum flavum: a technical note

Introduction

A variety of surgical procedures have been introduced to treat patients with thoracic myelopathy (TM) caused by ossification of the ligamentum flavum (OLF). However, they are accompanied by significant trauma and risk, and their surgical outcomes are not always satisfactory.

Aim

To describe a bilateral translaminar osseous-channel assisted posterior percutaneous full-endoscopic ligamentectomy decompression (p-PELD) technique as a novel minimally invasive procedure for treating patients with TM due to OLF.

Material and methods

A 51-year-old female patient with persistent thoracolumbar back pain and progressive numbness in the bilateral lower extremities for 2 years underwent percutaneous vertebroplasty (PVP) for T11 osteoporotic compression fractures (OCF) in a regional hospital one week prior to hospitalization. TM caused by canal stenosis and dorsal spinal cord compression at T10/11 secondary to OLF and an OCF at T11 were diagnosed based on clinical presentations and radiologic examinations. After bilateral p-PELD for TM was performed at T10/11, the result was confirmed based on postoperative radiographic and clinical results.

Results

The bilateral OLF was completely removed by the p-PELD technique. No complications were encountered, and her symptoms were sufficiently improved after surgery. The VAS score was 6 points preoperatively and decreased to 0 points at the last follow-up (24 months). The modified Japanese Orthopaedic Association (mJOA) score improved from 2 points preoperatively to 10 points at the final follow-up.

Conclusions

As a minimally invasive technique, the bilateral translaminar osseous-channel assisted p-PELD procedure provided precise and sufficient decompression for the treatment of OLF-related TM.

Posterior Percutaneous Endoscopic Technique Through Bilateral Translaminar Osseous Channels for Thoracic Spinal Stenosis Caused by Ossification of the Ligamentum Flavum Combined with Disk Herniation at the T10-11 Level: A Technical Note

BACKGROUND

The occurrence rate of thoracic spinal stenosis caused by ossification of the ligamentum flavum combined with disk herniation is lower than that of ossified ligamentum flavum in the thoracic spine, and the treatment method has rarely been reported. In this paper, we applied an endoscopic technique to a patient with thoracic spinal stenosis caused by ossification of the ligamentum flavum combined with disk herniation at the T10-11 level.

METHODS

We performed surgical decompression of the thoracic spinal cord for a patient diagnosed with thoracic spinal stenosis at the T10-11 level caused by ossification of the ligamentum flavum combined with disk herniation using percutaneous endoscopic surgery via the bilateral translaminar osseous channel approach. Pre- and postoperative computed tomography (CT) scan and magnetic resonance imaging (MRI) examinations were performed, and pre- and postoperative neurologic status was evaluated using the Modified Japanese Orthopaedic Association and visual analog scale scores.

RESULTS

The ossified ligamentum flavum and herniated disk material were removed through this osseous channel. Postoperative CT and MRI scanning revealed adequate decompression of the spinal cord at the T10-11 level. The patient was discharged home on postoperative day 3. At 6-month postoperative follow-up, the patient experienced complete resolution of T12 dermatomal numbness. The strength in her bilateral lower extremities improved slightly to grade 5.

CONCLUSIONS

We have applied percutaneous endoscopic surgery via bilateral translaminar osseous channels for the treatment of thoracic spinal stenosis caused by ossification of the ligamentum flavum combined with disk herniation. This surgery could provide sufficient decompression for thoracic spinal cord with minimum trauma.

Identification of crucial miRNAs and lncRNAs for ossification of ligamentum flavum

The present study aimed to screen crucial micro (mi)RNAs and long non-coding (lnc)RNAs involved in the development of ossification of ligamentum flavum (OLF) based on the miRNA-mRNA and lncRNA-miRNA-mRNA competing endogenous (ce)RNA regulatory network analyses, which are rarely reported. The differentially expressed genes (DEGs), differentially expressed lncRNAs (DELs) and differentially expressed miRNAs (DEMs) between 4 OLF and 4 healthy controls were identified using two microarray datasets GSE106253 and GSE106256 collected from the Gene Expression Omnibus database. A protein-protein interaction (PPI) network was constructed, followed by calculation of topological characteristics and sub-module analysis in order to obtain hub DEGs. The miRNA-mRNA and lncRNA-miRNA networks that were established based on their interaction pairs, obtained from miRwalk and starBase databases, respectively, were integrated to form the ceRNA network. The underlying functions of mRNAs were predicted using the Database for Annotation, Visualization and Integrated Discovery (DAVID). The present study screened 828 DEGs, 119 DELs and 81 DEMs between OLF and controls. PPI network and module analyses identified interleukin (IL)10, adenylate cyclase (ADCY)5, suppressor of cytokine signaling (SOCS)3, G protein subunit gamma (GNG) 4, collagen type II α 1 chain (COL2A1) and collagen type XIII α 1 chain (COL13A1) as hub genes. The miRNA-mRNA network analysis demonstrated IL10 could be regulated by miR-210-3p, while COL13A1 and COL2A1 could be modulated by miR-329-3p and miR-222-5p, respectively. lncRNA-miRNA-mRNA ceRNA network analysis identified that small nucleolar RNA host gene 16-hsa-miR-196a-5p-SOCS3, ankyrin repeat and SOCS box containing 16-AS1-hsa-miR-379-5p-GNG4, nuclear enriched abundant transcript 1-has-miR-181b-5p-ADCY5, rhophilin 1-AS1-hsa-miR-299-3p-WNT7B interaction axes may be crucial. DAVID analysis predicted IL10, ADCY5, GNG4 and SOCS3 were involved in ‘adaptive immune response’, ‘Chemokine signaling pathway’ and ‘regulation of apoptosis’ processes, while COL2A1, COL13A1 and WNT7B may be ossification related. In conclusion, the identification of these crucial miRNAs and lncRNAs may be conducive for explaining the pathogenesis of OLF and provide certain natural, endogenous and nontoxic drug targets for the treatment of OLF.

Clinical Outcomes and Prognostic Factors in Patients With Myelopathy Caused by Thoracic Ossification of the Ligamentum Flavum

Objective

The objective of this study was to investigate the surgical outcomes and prognostic factors for thoracic ossification of the ligamentum flavum (OLF) after decompressive laminectomy, focusing on the quantitative signal intensity ratio (SIR) of preoperative magnetic resonance imaging (MRI) and its prognostic significance.

Methods

We retrospectively reviewed 24 patients who previously underwent total laminectomy to remove OLF from 2010 to 2015. MRI and computed tomography were performed to detect OLF. The SIR between the regions of interest of high signal intensity lesions and the normal cord at the T1–2 disc levels was calculated. We divided patients into 2 groups based on the extent of the modified Japanese Orthopaedic Association (JOA) recovery rate (RR): good (RR ≥ 50%) and poor (RR < 50%).

Results

The mean preoperative and postoperative modified JOA scores for thoracic myelopathy were 6.67 ± 1.73 and 8.63 ± 1.81, respectively (p < 0.001). The preoperative JOA score (7.5 vs. 5.83, p = 0.028), postoperative JOA score (9.83 vs. 7.42, p = 0.000), and SIR (1.16 vs. 1.41, p = 0.009) were significantly different between the good and poor RR groups. A higher preoperative JOA score and lower SIR were associated with a good RR according to the JOA criteria.

Conclusion

The clinical outcomes for thoracic OLF after decompressive laminectomy were favorable. A higher RR was correlated with a lower SIR and higher preoperative modified JOA score. Therefore, a relatively low SIR on MRI and a relatively high preoperative JOA score could be positive prognostic indicators for the JOA RR in patients with thoracic OLF.

Outcomes and Complications Following Laminectomy Alone for Thoracic Myelopathy due to Ossified Ligamentum Flavum: A Systematic Review and Meta-Analysis

STUDY DESIGN

Systematic review and meta-analysis.

OBJECTIVE

Examine the functional outcomes and complications following laminectomy for thoracic myelopathy due to ossification of the ligamentum flavum (OLF).

SUMMARY OF BACKGROUND DATA

OLF is a rare condition that can cause thoracic myelopathy. Laminectomy is a procedure that can be performed to decompress the spinal cord in patients with thoracic myelopathy due to OLF. Few studies have examined postoperative outcomes and complications following laminectomy for thoracic myelopathy secondary to OLF.

METHODS

A systematic review and meta-analysis was performed. Literature search yielded six studies that met our selection criteria. Study characteristics and baseline patient demographics were extracted from each study. Primary outcomes included pre- and postoperative Japanese Orthopedic Association (JOA) scores and perioperative complications including dural tears, cerebrospinal fluid (CSF) leaks, neurological deficits, surgical site infections, and other complications. We calculated pooled proportion estimates for JOA scores and complications using a random effects model.

RESULTS

A total of 137 patients were included. The pooled pre- and postoperative JOA scores were 5.08 (95% confidence interval [CI], 2.70-7.47; I = 98%) and 8.29 (95% CI, 7.73-8.85; I = 18%), respectively, with a mean improvement of +3.03 points (95% CI, 1.08-4.98; I = 88%). Pooled proportion estimates for dural tears, CSF leaks, infections, and early neurological deficits were 18.4% (95% CI, 12.6-26.1; I = 0%), 12.1% (95% CI, 6.6-21.2; I = 0%), 5.8% (95% CI, 2.1-15.4; I = 0%), and 5.7% (95% CI, 2.2-14.3; I = 0%), respectively.

CONCLUSION

Thoracic myelopathy secondary to OLF can be treated with laminectomy. However, despite some improvement in JOA score, functional status remains poor postoperatively. Perioperative complications are common, with dural tears and CSF leaks occurring most frequently. OLF is an uncommon condition and more research is needed to better understand how we can improve the outcomes of laminectomy alone for the treatment of thoracic myelopathy due to OLF.

LEVEL OF EVIDENCE

3.

Clinical relation among dural adhesion, dural ossification, and dural laceration in the removal of ossification of the ligamentum flavum

BACKGROUND CONTEXT

Dural laceration frequently occurs during surgery in patients with ossification of the ligamentum flavum (OLF), mainly because of dural adhesion (DA) and dural ossification (DO) between the ligamentum flavum and the dura mater. However, the radiological predictive factors of DA in OLF have rarely been reported.

PURPOSE

The objective of this study was to determine the preoperative radiological signs for predicting intraoperative DA in OLF by using preoperative magnetic resonance imaging (MRI) and computed tomography (CT).

STUDY DESIGN

This is a retrospective study.

PATIENT SAMPLE

This study included 182 patients who underwent decompressive laminectomy and OLF removal from 2005 to 2014.

OUTCOME MEASURE

Demographic data, preoperative neurologic status, surgical procedure and results, and intraoperative and postoperative complications were analyzed. Clinical outcome was assessed with the Japanese Orthopaedic Association score.

MATERIALS AND METHODS

Depending on the morphologic appearance of OLF in preoperative radiographs, we aimed to investigate the prevalence of intraoperative DA and DO. We used the following factors of representative classifications: (1) surface appearance, (2) "double-layer" or "tram-track" sign, (3) cross-sectional area of the stenosed level, (4) Sato classification as axial classification, (5) Kuh classification as sagittal classification, and (6) high-signal-intensity change on T₂-weighted MRI.

RESULTS

Intraoperative evidence of DA was observed in 52 patients (29%), and DO was observed in 23 patients (13%). Twenty-seven patients (15%) had dural laceration during surgery. Statistically, DA was closely associated with the non-uniform type of surface appearance (odds ratio 5.396, p=.001) and with the presence of either a double-layer sign or a tram-track sign (odds ratio 11.525, p<.001). In the preoperative CT and MRI, 21 out of 23 patients with DO showed a "double-layer sign" or a "tram-track sign."

CONCLUSIONS

This study identified two predictive factors of DA in OLF, which were the non-uniform surface appearance and the presence of a double-layer sign or a tram-track sign. The presence of DO in OLF was closely associated with a double-layer sign or a tram-track sign in the preoperative radiological images.

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.

Transforaminal en bloc resection for the treatment of thoracic ossification of the ligamentum flavum: Retrospective cohort study

BACKGROUND

Our purpose is to introduce transforaminal en bloc resection for the treatment of thoracic ossification of ligamentum flavum, and report outcomes of the procedure.

PATIENTS AND METHODS

The record of patients with symptomatic thoracic ossification of the ligamentum flavum who received transforaminal en block resection from October 2010 to September 2014 were retrospectively reviewed. Outcomes were Japanese Orthopaedic Association (JOA) lower extremity motor dysfunction and sphincter dysfunction scores.

RESULTS

Seventeen patients (10 males, 7 females) with a median age of 60 years were included in the analysis. Surgery was performed as planned without complications in all patients. One segment decompression was performed in 1 case, 2 segment in 9 cases, 3 segment in 3 cases, and 4 segment in 4 cases. The median lower extremity motor dysfunction score was significantly higher at 2 weeks, 3 months, and 6 months postoperatively, and the end of follow-up, than before surgery (median score: 2, 2, 3, 3, respective, vs. 1, all, p ≤ 0.008). There were no significant differences in JOA sphincter dysfunction score between the different time points.

CONCLUSION

Transforaminal en bloc resection is a safe and effective method for the treatment of thoracic ossification of the ligamentum flavum.

Ossification of the ligamentum flavum

Ossification of the ligamentum flavum (OLF or OYL: ossification of the yellow ligament) usually occurs at the lower thoracic level and causes various types of neurological symptoms in accordance with the compression level of the spinal cord, the nerve roots, the conus medullaris, and the cauda equina. Although the greatest compression level to the nerve tissues is thought to be the most pathognomonic one, it is difficult to diagnose it in some cases. The effectiveness of conservative treatment such as applying a corset is small. Early surgical treatment is strongly recommended for the patients with spastic gait, severe decrease of muscle power in the lower extremities, bladder-bowel disturbance, combined ossification of the posterior longitudinal ligament at the same level, and severe compression to the spinal cord due to thickly hypertrophied ossification. However, numbness of the lower extremities and spastic gait tend to remain even after surgery.

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.

Minimally invasive surgery for resection of ossification of the ligamentum flavum in the thoracic spine

Introduction

Thoracic ossification of the ligamentum flavum (TOLF) is a common cause of progressive thoracic myelopathy. Surgical decompression is commonly used to treat TOLF.

Aim

To evaluate the clinical outcomes of microsurgical decompression of TOLF via a paraspinal approach, using a percutaneous tubular retractor system.

Material and methods

First, three-dimensional (3D) image reconstruction and printed models were made from thin computed tomography scans for each patient. Then, 3D computer-assisted virtual surgery was performed using the 3D reconstruction to calculate the precise location and sizes of the bone window and the angle of insertion of the percutaneous tubular retractor system. In total, 13 patients underwent the surgery through the percutaneous micro channel unilateral vertebral approach under electrophysiological monitoring. Five days after the surgery, increased creatine phosphokinase levels returned to preoperative levels. The Japanese Orthopedic Association (JOA) score was improved and computed tomography reconstruction and magnetic resonance imaging of the thoracic spine showed that decompression was achieved without injuries to the spinal cord or nerve root. The stability of the spine was not affected, nor were any deformities of the spine detected. Finally, nerve functional recovery was achieved with minimal injury to the paraspinal muscle, articulum, spinous process and ligament.

Results

The mean operative time was 98.23 ±19.10 min, and mean blood loss was 19.77 ±5.97 ml. At a mean follow-up of 13.3 months (median: 12 months), the mean JOA score was 7.54 ±1.13 at the final follow-up, yielding a mean RR of 49.10 ±15.71%. Using The recovery rate, 7 (53.85%) patients had good outcomes, 5 (38.46%) patients had a fair outcome, and 1 (7.69%) patient had poor outcomes, indicating significant improvement by the final follow-up examination (p < 0.05).

Conclusions

The 3D printed patient model-based microsurgical resection of TOLF via the paraspinal approach can achieve decompression of the spinal canal with minimal complications, faster recovery and improved stability of the vertebral body.