Full endoscopic surgery for calcium pyrophosphate deposition disease (CPPD) in the cervical ligamentum flavum: report of two cervical myelopathy cases

Calcium pyrophosphate deposition disease (CPPD), known as pseudogout, is characterized by the accumulation of calcium pyrophosphate crystals in musculoskeletal structures, primarily joints. While CPPD commonly affects various joints, involvement in the cervical spine leading to myelopathy is rare. Surgical intervention becomes necessary when conservative measures fail, but reports on full endoscopic surgeries are extremely rare. We present two successful cases where full endoscopic systems were used for CPPD removal in the cervical spine. The surgical technique involved a full endoscopic approach, adapting the previously reported technique for unilateral laminotomy bilateral decompression. Full-endoscopic removal of cervical CPPD inducing myelopathy were successfully removed with good clinical and radiologic outcomes. The scarcity of endoscopic cases for cervical ligamentum flavum CPPD is attributed to the condition's rarity. However, our successful cases advocate for endoscopic surgery as a potential primary treatment option for CPPD-induced cervical myelopathy, especially in elderly patients or those with previous cervical operation histories. This experience encourages the consideration of endoscopic surgery for managing cervical ligamentum flavum CPPD as a viable alternative.

Lumbar Spinous Process-Splitting Technique for Ligamentum Flavum Cyst Removal

BACKGROUND

 Laminotomy for lumbar stenosis is a well-defined procedure and represents a routine in every neurosurgical department. It is a common experience that the uni- or bilateral paraspinal muscle detachment, together with injury of the supra- and interspinous ligaments, can lead to postoperative pain. In the literature, the application of a minimally invasive technique, the lumbar spinous process-splitting (LSPS) technique, has been reported.

METHODS

 In this study, we present a case series of 12 patients who underwent LSPS from September 2019 to April 2020. Two patients had a cyst of the ligamentum flavum, eight a single-level lumbar canal stenosis (LCS), and two a two-level LCS. Moreover, we propose a novel morphological classification of postoperative muscle atrophy and present volumetric analysis of the decompression achieved.

RESULTS

 There were no complications related to this technique. In all patients, the vertebral canal area was more than doubled by the procedure. The muscle sparing showed grade A, according to our classification.

CONCLUSION

 To our knowledge, this is the first description of this surgical technique and the first LSPSL case series in Europe. Furthermore, cases of ligamentum flavum cyst removal using this safe and effective technique have not yet been reported.

Safety and efficacy of one-hole split endoscope technique for surgical treatment of thoracic ossification of the ligamentum flavum

Surgical intervention is typically recommended for thoracic ossification of the ligamentum flavum (TOLF). This study aimed to evaluate the efficacy and safety of a novel non-coaxial one-hole split endoscope (OSE) technique for treating TOLF. We performed OSE procedure on 13 patients with TOLF from June 2022 to July 2023. The mean operative time was 117.5 ± 15.4 min. VAS scores for lower limbs decreased from 6.5 ± 0.8 preoperative to 1.6 ± 0.4 at the last follow-up (P < 0.001). ODI scores improved from 62.4 ± 5.7 preoperative to 18.6 ± 2.2 at the last follow-up (P < 0.001), and mJOA scores increased from 5.1 ± 1.6 preoperative to 8.4 ± 1.5 at the latest follow-up (P < 0.001). All patients achieved ASIA scale grade D or E at the final follow-up, except for two patients remained residual limb numbness. None of the thirteen patients suffered from severe perioperative complications. The OSE technique proves to be a safe and effective procedure for treating TOLF or even with dura mater ossification, characterized by minimal surgical trauma, relatively smooth learning curve and flexible operation.

Quantitative evaluation of the lumbar ligamentum flavum using MRI T2-mapping: Efficacy of its clinical application in patients with lumbar spinal stenosis

OBEJECTIVE

To perform a magnetic resonance imaging T2-mapping of the ligamentum flavum in healthy individuals and patients with lumbar spinal stenosis scheduled for surgery and compare the T2 relaxation times.

SUBJECTS AND METHODS

The T2 relaxation time of the ligamentum flavum was compared among 3 groups, healthy young individuals (H group (age< 50)), healthy middle-aged and older individuals (H group (age≥50)), and patients with lumbar spinal stenosis (L group). Additionally, the thickness of the ligament was measured in the axial image plane, and the occupied area ratio of each fiber was measured by staining the surgically obtained ligament, and each was correlated with the T2 relaxation time. We also evaluated the adhesion of the ligamentum flavum with the dura mater during the surgery.

RESULTS

The T2 relaxation times were significantly prolonged in H group (age ≥50) and L group (P < 0.001) compared to H group (age<50). The relationship between collagen fiber and T2 relaxation times was significantly positive (r = 0.720, P < 0.001). Moreover, the relaxation times were significantly prolonged in those with adhesion of the ligamentum flavum with the dura mater (P < 0.05). The cut-off for the relaxation time was 50 ms (sensitivity: 62.50%, false positive rate: 10.8%).

CONCLUSION

Healthy middle-aged and older individuals and patients with lumbar spinal stenosis and adhesion of the ligamentum flavum with the dura mater have prolonged T2 relaxation times. Hence, the adhesion between the ligamentum flavum and dura mater should be considered in cases with a relaxation time ≥50 ms.

The Quality of Life of the Patients with Thoracic Ossification of the Ligamentum Flavum after Surgery Using EQ-5D-5L

OBJECTIVE

There is a lack of studies on the quality of life (QoL) after posterior laminectomy in patients with thoracic ossification of the ligamentum flavum (TOLF), and risk factors associated with poor prognosis remain controversial. Therefore, the present study was conducted to illustrate the QoL for TOLF patients after surgery and determine its relationship with their demographic, surgery-related, clinical characteristics and imaging data.

METHODS

One hundred and eighteen patients diagnosed with thoracic myelopathy because of TOLF were enrolled in this retrospective study. They all underwent posterior decompressive laminectomy from August 2010 to January 2022. The QoL was evaluated based on the EQ-5D-5L. Collecting gender, age, number of operations, compressed segments, Frankel grade, complications, body mass index (BMI), symptoms and duration, modified Japanese Orthopaedic Association (mJOA) score (preoperative), follow-up time and type of ossification, increased signal on Sagittal T2-weighted Images (ISST2I), occupancy rate and analyzing by Mann-Whitney U-test, Kruskal-Wallis test, the χ2 -test, and logistic regression tests.

RESULTS

Average follow-up 70.8 months (18-149), the mean age was 59.74 ± 9.81 years and the mean score for the QoL based on the EQ-5D-5 L and visual analogue scale (VAS) score were 0.71 ± 0.28 and 78.88 ± 10.21 at the final follow-up. Moderate and severe problems were found in the pain/discomfort in 22.0% of the patients. These mobility and usual activities numbers were slightly higher (24.6% and 30.4%, respectively). The mean scores for QoL and VAS were significantly higher in patients with mild and moderate neurological impairment, normal BMI, <60 years of age, no dural tears, symptom relief at hospital discharge, unilateral and bilateral ossification on axial CT scan, ≤ 50% spinal canal occupancy on CT and MRI, and none or fuzzy on ISST2I.

CONCLUSION

QoL after posterior laminectomy in TOLF patients is generally satisfactory compared to preoperative levels. Preoperative mJOA score, Age, comorbid diabetes, the major symptom is activity limitation, BMI, ISST2I, Intraoperative dural tears and spinal canal occupancy rate correlate significantly with the corresponding dimensions and are predictive. Age, spinal canal occupancy rate, ISST2I, preoperative mJOA score, BMI are significantly associated with and have predictive value for overall postoperative QoL.

Lamina-Lifting Suspension Modification in Bridge Crane Technique in Treatment of Severe Thoracic Ossification of the Ligamentum Flavum (TOLF)

BACKGROUND The aim of this study was to investigate the effectiveness and potential complications of combining a lamina-lifting suspension system with the bridge crane technique in treating thoracic ossification of the ligamentum flavum (TOLF) with thoracic myelopathy. MATERIAL AND METHODS A patient with severe TOLF and myelopathy was treated using a lamina-lifting suspension system combined with bridge crane technique. The brief surgical procedure involved implantation of internal fixation, separation of laminae, installation of cross-bridges, reverse lifting, and fixation of cross-bridges. The modified Japanese Orthopaedic Association (mJOA) scale, Hirabayashi recovery rate, and ASIA grade of the patient were recorded. The canal occupation ratio (COR) and spinal cord status were evaluated by imaging data. RESULTS The surgical intervention significantly enhances the patient's lower limb function, as evidenced by an increase in mJOA score from 5 preoperatively to 11 at terminal follow-up. The Hirabayashi recovery rate after surgery ranges between 25% and 50%. Additionally, ASIA classification improved to grade E. Imaging data showed that the ossification of the thoracic vertebrae had subsided, while the volume of the local spinal canal had recovered and the spinal cord injury had been completely relieved. No adverse effects or complications were observed. CONCLUSIONS The lamina-lifting suspension system preserves the benefits of bridge crane technique while also augmenting the traction of a post laminae-OLF complex (LOC) suspension, rendering it more secure and manageable. Nevertheless, further sample analysis and research are required in the future.

Evolution of sagittal spinal shape for the development of thoracic ossification of ligamentum flavum

Thoracic ossification of the ligamentum flavum (TOLF) is a rare pathology for which limited research exists. While it is known that mechanical factors play a role in the development of TOLF, little is currently understood about the sagittal alignment and related mechanical stress involved in its development. This study aims to describe the sagittal alignment of patients with TOLF based on the pathologic evolution of the Roussouly classification. The current study evaluated the preoperative Roussouly type in consecutive patients who underwent posterior decompressive laminectomy with or without posterior screw fixation for TOLF between January 2015 and December 2021. The post-evolution sagittal alignments were analyzed using the classic Roussouly classification based on sacral slope (SS). To determine the pre-evolution Roussouly type, the patients were retrospectively classified using their individual PI and PT values. Lumbopelvic parameters and morphological index including inflection point (IP), lumbar apex (LA), and lordosis distribution index (LDI) were also evaluated. Forty-three patients (21 women and 22 men) were included; their mean age was 64.21 ± 11.01 years (range 43-81). The most affected level was T10-11 (48.83%). The mean PI was 50.81 ± 9.56°, the mean SS was 33.11 ± 8.61°and the mean PT was 17.69 ± 7.89°. According to the post-evolution Roussouly classification, type 2 shape was the most frequently observed type (n = 23, 53.5%) in the post-evolution classification while type 3 was the most common type observed in the pre-evolution classification (n = 22, 51.5% and P = .00). The level of IP and LA in type 3 moved caudally (around L2 and L4/5 level, respectively) and the LDI increased (77.98 ± 8.08%) than the normal standard value. The authors found that the majority of the patients had a false type 2 spine, which had evolved pathologically from Roussouly type 3 and exhibited increased LDI, a lowered level of IP, and a lowered level of LA. These changes of spinal shape, including the transition to long hypolordosis and increased length of the thoracic kyphosis, may have accentuated tensile stress at the lower thoracic spine and contributed to the development of TOLF.

Minimally invasive fenestration for decompression of C2-C3 spinal stenosis

Conventional techniques in neurosurgery such as laminectomy have been extensively displaced by minimally invasive types, owing to the character of complexity of cervical spinal region. Spinal canal stenosis at C2-C3 level is documented in the literature with the majority being caused by intervertebral disc herniations.This case reports a patient who presented with classical myelopathy symptoms and significant thickening of ligamentum flavum, while minimal spondylosis was detected at C2-C3 level. The decompression was performed from posterior approach and limited to the removal of ligamentum flavum with minimal resection of adjacent laminae, no fixation and no disc evacuation. After surgery, there was a significant improvement with preserved spinal stability.Although the anterior approach is more common for cervical spine, universal access site has not been defined in literature. We suggest that minimal decompression produces desirable effects with no need for fusion and preserving adequate stability of spinal complex.

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.

Prevalence and distribution of ossification of the ligamenta flava in a 16th-18th century skeletal population sample from Poland

OBJECTIVE

This study aimed to determine the prevalence of the ossification of the ligamenta flava (OLF) among skeletal remains from Poland.

MATERIALS AND METHODS

124 skeletons aged 25 years and older were analyzed. The presence and size of OLF were observed macroscopically. OLF was recorded at the cranial and caudal attachment sites of each vertebra. The following factors were analyzed: age at death, sex, and presence of other spondyloarthropathies.

RESULTS

The crude prevalence of OLF in the analyzed series was 68.55 %. OLF was located most frequently in the lower thoracic spine. A statistically significant relationship was observed between the presence of OLF and age at death. OLF coincided with degenerative spondyloarthropathies of the thoracolumbar spine.

CONCLUSIONS

The results of this study indicate that OLF was not a rare condition in past populations of European ancestry. Analysis of OLF prevalence in skeletal materials can contribute to reconstruction of the conditions and lifestyles of past people.

SIGNIFICANCE

This study shed new light on the prevalence of OLF and provides information on the variability of OLF in past European populations. The evaluation of the prevalence of OLF represents an important contribution to the field of paleopathology in understanding disease changes in prehistoric and historic human populations.

LIMITATIONS

The analyzed material came from unknown populations without demographic data. Sex and age at death were assessed using standard anthropological methods.

SUGGESTIONS FOR FURTHER RESEARCH

It is important to understand the influence of sociocultural factors and physical activity patterns on the development of OLF.

Learning Curve and Clinical Outcomes of Ultrasonic Osteotome-based En Bloc Laminectomy for Thoracic Ossification of the Ligamentum Flavum

OBJECTIVE

Despite rapid advances in minimally invasive surgery, en bloc laminectomy remains the most common surgical approach for treating thoracic ossification of the ligamentum flavum (TOLF). However, the learning curve of this risky operation is rarely reported. Therefore, we aimed to describe and analyze the learning curve of ultrasonic osteotome-based en bloc laminectomy for TOLF.

METHODS

Among 151 consecutive patients with TOLF who underwent en bloc laminectomy performed by one surgeon between January 2012 and December 2017, we retrospectively analyzed their demographic data, surgical parameters, and neurological function. Neurological outcome was evaluated with the modified Japanese Orthopaedic Association (mJOA) scale, and the Hirabayashi method was used to calculate the neurological recovery rate. The learning curve was assessed with logarithmic curve-fitting regression analysis. Univariate analysis methods were used for statistical analysis, including t-test, rank sum test, and chi-square test.

RESULTS

A total of 50% of learning milestones could be reached in approximately 14 cases, and the asymptote in 76 cases. Therefore, 76 of the 151 enrolled patients were defined as the "early group," and the remaining 75 were delimitated as the "late group" for comparison. There was a significant intergroup difference in the corrected operative time (94.80 ± 27.77 vs 65.93 ± 15.67 min, P < 0.001) and the estimated blood loss (median 240 vs 400 mL, P < 0.001). The overall follow-up was 83.1 ± 18.5 months. The mJOA significantly increased from a median of 5 (IQR: 4-5) before the surgery to 10 (IQR: 9-10) at the last follow-up (P < 0.001). The overall complication rate was 37.1%, and no significant intergroup difference was found, except for the incidence of dural tears (31.6% vs 17.3%, p = 0.042).

CONCLUSION

Initially, mastering the en bloc laminectomy technique using ultrasonic osteotome for TOLF treatment can be challenging, but the surgeon's experience improves as the operative time and blood loss decrease. Improved surgical experience reduced the risk of dural tears but was not associated with the overall complication rate or long-term neurological function. Despite the relatively long learning curve, en bloc laminectomy is a secure and valid technique for TOLF treatment.

How I do it: the biportal endoscopic inclined-ipsilateral technique to decompress the lumbar lateral recess

BACKGROUND

Various full-endoscopic techniques have been developed to reach the lateral recess of the lumbar spine. However, specialized surgical tools, including expensive spinal endoscopic systems, and a steeper learning curve to mastering the technique are required.

METHOD

We present a novel target-addressed unilateral biportal endoscopic technique to reach directly the lumbar lateral recess, particularly useful at L4-L5 and L5-S1. The technique follows an inclined-ipsilateral trajectory to preserve the lateral extension of ligamentum flavum and the facet joint as much as possible.

CONCLUSION

This technique was associated with all the advantages of minimally invasive decompressive procedures and outstanding outcomes.

A muscle-preserving, spinous process-splitting approach for ossification of the ligamentum flavum in the thoracic spine in professional athletes: a report of three cases

A muscle-preserving, spinous process-splitting approach may be a less invasive approach to conventional laminectomy in patients with thoracic ossification of the ligamentum flavum. Few reports have discussed the usefulness of this procedure for thoracic lesions in professional athletes who need highly active thoracic spinal function after surgery. The treatment of thoracic ossification of the ligamentum flavum using a spinous process-splitting approach in 3 professional athletes is presented. In all three cases the patients could return to play within 3 months after surgery without complications, and in two of the cases, there was no spinal deformity or local recurrence of ossification of the ligamentum flavum at the final follow-up at least 8 years after surgery. The spinous process-splitting approach could be a safe procedure for multi-level and all other forms of ossification of the ligamentum flavum and is less invasive to the paraspinal muscles, relieves back symptoms, and restores function for athletes.

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.

Hypertrophied posterior longitudinal ligament and ligamentum flavum causing myelopathy: a case report and literature review

INTRODUCTION

The occurrence of concurrent hypertrophied posterior longitudinal ligament (HPLL) and hypertrophied ligamentum flavum (HLF) in the thoracic spine is a very rare presentation. This case report describes a young female who developed thoracic myelopathy secondary to a combination of both thoracic HPLL and HLF.

CASE PRESENTATION

A 30-year-old previously well female was referred for an MRI scan of the thoraco-lumbar spine. She was having lower limb weakness and difficulty in walking, which had progressed over 3 months. On examination, she was found to have spastic lower limbs with associated motor weakness. Her biochemical investigations were unremarkable. The MRI scan showed HPLL, which was uniformly hypointense on T2W images and was isointense on T1W images. The hypertrophied segment was extending from T2 level to T7 level. Similarly, the ligamentum flavum was hypertrophied from T1 level to T8 level. The thoracic spinal cord was seen compressed between the hypertrophied ligaments. The compressed cord showed central hyperintense signal pattern in T2W images. CT scan of the thoracic spine did not show any calcifications or ossifications along the ligaments. Patient underwent posterior decompressive surgery and she had an uneventful recovery.

DISCUSSION

Although few cases of HPLL and HLF were reported in older patients in literature, both these conditions were found in this patient at a younger age. HPLL and HLF are thought to be precursors of ossification of these ligaments and these patients need long-term follow-up.

[Application of unilateral biportal endoscopy technique in single-segment thoracic ossification of ligamentum flavum]

Objective

To investigate the safety and effectiveness of unilateral biportal endoscopy (UBE) technique in the treatment of single-segment thoracic ossification of ligamentum flavum (TOLF).

Methods

Between August 2020 and December 2021, 11 patients with single-segment TOLF were treated with UBE technique. There were 6 males and 5 females, with an average of 58.2 years (range, 49-72 years). The responsible segment was T _{6, 7} in 1 case, T _{7, 8} in 1 case, T _{8, 9} in 2 cases, T _{9, 10} in 2 cases, T _{10, 11} in 2 cases, and T _{11, 12} in 3 cases. Imaging examination showed that the ossification were located on the left side in 4 cases, on the right side in 3 cases, and on bilateral sides in 4 cases. The main clinical symptoms were chest and back pain or lower limb pain, all accompanied by lower limb numbness and fatigue. The disease duration ranged from 2 to 28 months (median, 17 months). The operation time, postoperative hospital stay, and complications were recorded. Visual analogue scale (VAS) score was used to evaluate the chest and back pain and low limb pain, and Oswestry disability index (ODI) and Japanese Orthopedic Association (JOA) score were used to evaluate functional recovery before operation and at 3 days, 1 month, 3 months after operation, and last follow-up. The anteroposterior diameter of the coronal spinal canal was measured by CT before and after operation to evaluate the effect of surgical decompression.

Results

All operations were successfully completed. The operation time was 50-105 minutes, with an average of 80.0 minutes. No postoperative complication such as dural sac tear, cerebrospinal fluid leakage, spinal nerve injury, or infection occurred. The postoperative hospital stay was 2-5 days, with an average of 3.1 days. All incisions healed by first intention. All patients were followed up 6-22 months, with an average of 14.8 months. CT measurement at 3 days after operation showed that the anteroposterior diameter of the spinal canal was (8.63±1.61) mm, which was significantly larger than that before operation [(3.67±1.37) mm] ( t=-12.181, P<0.001). The VAS score of chest and back pain and lower limb pain and ODI at each time point after operation were significantly lower than those before operation ( P<0.05). The above indexes were further improved after operation, except that there was no significant difference between at 3 months after operation and at last follow-up ( P>0.05), the differences between other time points were significant ( P<0.05). There was no recurrence during the follow-up period.

Conclusion

UBE technique is a safe and effective method to treat single-segment TOLF, but its long-term effectiveness needs to be further studied.

Incidence and risk factors of dural ossification in patients with thoracic ossification of the ligamentum flavum

OBJECTIVE

Dural ossification (DO) is a common clinical feature in patients with thoracic ossification of the ligamentum flavum (OLF) and associated with the increased risk of perioperative complications. However, few studies have been conducted to determine the incidence and independent risk factors of DO in patients with thoracic OLF. The aim of this retrospective study was to determine the incidence and independent risk factors of DO in patients with thoracic OLF.

METHODS

A total of 107 patients with thoracic OLF who were admitted to the authors' hospital from December 2020 to December 2021 were included in this study. The independent risk factors of DO in patients with thoracic OLF were determined through univariate analysis followed by multivariate logistic regression analysis with p < 0.05. The diagnostic efficacy of the DO in OLF (DO-OLF) risk classification model was determined on the basis of independent risk factors and evaluated on the basis of sensitivity, specificity, and agreement rate.

RESULTS

The incidence of DO in patients with thoracic OLF was 35% (37/107 patients). The tuberous type according to the Sato classification (OR 9.75, p < 0.01) and larger (≥ 9°) supine local kyphosis angle (LKA) (OR 8.13, p < 0.01) were two independent risk factors of DO in thoracic OLF. The DO-OLF risk classification, a novel approach for the diagnosis of DO in patients with thoracic OLF, was established on the basis of the combination of the tuberous type according to the Sato classification and larger supine LKA. The sensitivity, specificity, and agreement rate of this approach for distinguishing between patients with thoracic OLF at high and low risk of DO were 87%, 93%, and 91%, respectively.

CONCLUSIONS

The incidence of DO in patients with thoracic OLF was 35%. The tuberous type according to the Sato classification and larger supine LKA (≥ 9°) were independent risk factors of DO in patients with thoracic OLF. The novel DO-OLF risk classification approach could serve as an efficient method for predicting DO in patients with thoracic OLF.

Ligamentum flavum hypertrophy significantly contributes to the severity of neurogenic intermittent claudication in patients with lumbar spinal canal stenosis

Ligamentum flavum hypertrophy (LFH) is a known contributor to lumbar spinal canal stenosis (LSCS). However, the clinical significance and quantitative role of LFH compared to other components, such as disc bulging and facet hypertrophy, have not yet been examined. We investigated the correlation between the quantitative radiological factors, clinical symptoms, and outcomes in patients with LSCS. In total, 163 patients diagnosed with single-level (L4-L5) stenosis were included. The patients were divided into 2 groups according to claudication severity: >100 m for mild (n = 92) and < 100 m for severe (n = 71). The visual analog scale (VAS) was used to quantify back and leg pain, and the Oswestry Disability Index (ODI) and Short form-36 (SF-36) physical component summary (PCS) scores, and Macnab criteria were evaluated as clinical factors 6 months after treatment. We measured the baseline canal cross-sectional area, ligamentum flavum (LF) area, disc herniation area, dural sac area, fat area, and LF thickness using MRI. A comparative analysis was performed to evaluate the association between radiologic and clinical factors. Additionally, further comparative analyses between the types of surgeries were performed. Among various radiologic factors, the baseline LF thickness (odds ratio [OR] 1.73; 95% confidence interval [CI] 1.25-2.41) was the only major contributing factor to the severity of claudication in the multivariate logistic regression analysis. The types of surgery (decompression alone vs fusion) did not significantly differ in terms of their clinical outcomes, including back and leg VAS, ODI, SF-36 PCS, and satisfaction with the MacNab classification. LF thickness is a major factor contributing to claudication severity.

Banner cloud sign: a novel method for the diagnosis of dural ossification in patients with thoracic ossification of the ligamentum flavum

PURPOSE

Dural ossification (DO) is common in patients with ossification of the ligamentum flavum (OLF) and is the leading cause of dural tears. However, the methods used for DO diagnosis are limited. The purpose of this study was to propose a novel CT-based imaging sign, Banner cloud sign (BCs), and clarify its clinical characteristics and correlations with DO.

METHODS

57 OLF patients who underwent thoracic spine decompression surgery in our single-center between January- and October-2018 were recruited and divided into two groups based on the presence of DO. Patient demographics and radiographic data were analyzed. Hematoxylin-eosin staining and micro-CT were used to detect the micro-morphological changes of DO. The diagnostic value of BCs for DO was assessed by sensitivity and specificity.

RESULTS

12 patients with a total of 19 segments were diagnosed as DO. The incidence of DO was 21.1% (12/57) in OLF patients and 9.5% (19/200) in OLF segments. Patients with DO had a shorter disease duration and a higher incidence of cerebrospinal fluid leakage than those without DO. Hematoxylin-eosin staining and micro-CT showed that the dura mater was ossified and fused with ossified ligamentum flavum, and diffusion along the dura mater, like a banner cloud flying on the mountain. The sensitivity and specificity of BCs in DO diagnosis were 78.9 and 90.6%, respectively.

CONCLUSION

BCs can vividly and intuitively describe the imaging features of DO and has high diagnostic accuracy. It could be a promising and valuable method for the diagnosis of DO.

Cytokine Profile From the Ligamentum Flavum in Patients with Ossification of the Posterior Longitudinal Ligament in the Cervical Spine

STUDY DESIGN

Histological, immunohistochemical, and suspension array analyses of cytokine expression in human cervical ossification of the posterior longitudinal ligament (OPLL).

OBJECTIVES

The aim of this study was to determine whether changes in the cytokine profile reflect the maturation of chondrocytes and osteoblasts are associated with OPLL development.

SUMMARY OF BACKGROUND DATA

OPLL progresses gradually over a prolonged period and may lead to serious spinal cord complications. However, treatment methods only include conservative therapy for neurological symptoms or surgical decompression, whereas preventive therapy for OPLL remains nonexistent.

METHODS

Ligamentous samples were harvested from 24 patients with OPLL who underwent spinal surgery, and five control samples from cervical spondylotic myelo/radiculopathy patients without OPLL. Tissue sections were used for immunohistochemical studies and primary cells were cultured from the ligamentous samples for cytokine profiling. Using a suspension array system, concentrations of 27 inflammatory cytokines or growth factors were measured to generate the cytokine profiles.

RESULTS

Suspension array and immunoblot analysis revealed significant increments in the levels of interleukin (IL)-6, IL-1α, basic fibroblast growth factor, and RANTES in patients with OPLL. Immunohistochemical analysis further revealed that these factors were present in mesenchymal cells within the degenerative portion of the ligamentous matrix.

CONCLUSION

Our findings suggest that specific changes in the cytokine profile during ossification promote osteoblast differentiation, thereby providing new insights into OPLL pathogenesis. Moreover, this work supports the development of a new therapeutic method for preventing OPLL progression by regulating the cytokine profiles.Level of Evidence: 3.

Full-Endoscopic Decompression with the Application of an Endoscopic-Matched Ultrasonic Osteotome for Removal of Ossification of the Thoracic Ligamentum Flavum

BACKGROUND

Resection of the ossification of the thoracic ligamentum flavum (OTLF) with a high-speed burr may cause a high rate of perioperative complications, such as dural laceration and/or iatrogenic spinal cord injury.

OBJECTIVES

The aim of this study was to investigate the safety and feasibility of the endoscopic-matched ultrasonic osteotome in full-endoscopic spinal surgery for direct removal of OTLF.

STUDY DESIGN

Retrospective study.

SETTING

All data were from Honghui Hospital in Xi'an.

METHODS

This study conducted between December 2017 and December 2018, included 27 consecutive patients who met the study criteria, had single-level OTLF, and underwent full-endoscopic decompression under local anesthesia. The postoperative follow-up was scheduled at 1, 3, 6, and 12 months postoperatively. Outcomes evaluations included the Visual Analog Scale (VAS) score for lower extremity pain and the modified Japanese Orthopaedic Association (mJOA) score and improvement rate for the assessment of thoracic myelopathy. Removal of OTLF was measured by comparing the pre- and postoperative computed tomography (CT) and magnetic resonance imaging (MRI) scans.

RESULTS

The operation was completed in all patients without conversion to open surgery. The operation time ranged from 65 to 125 minutes (average, 83.7 ± 12.3 minutes). All patients were followed up for 12 to 18 months, with an average follow-up of 14.3 ± 1.3 months. Satisfactory neurologic decompression was confirmed by postoperative CT and MRI, and no revision surgery was required. The VAS and mJOA scores showed statistically higher improvement at the 1-month follow-up and the last follow-up compared with the preoperative assessment (P < 0.05). According to the improvement rate at the final follow-up, 20 cases were classified as good, 6 cases were fair, and 1 case remained unchanged.

LIMITATIONS

A single-center, noncontrol study.

CONCLUSIONS

The endoscopic-matched ultrasonic osteotome can be considered quite safe and feasible for direct removal of OTLF during full-endoscopic spinal surgery in strictly selected patients, as this allows for effective direct decompression of OTLF while minimizing trauma and instability. In addition, because of the design characteristics of the ultrasonic osteotome, surgical complications, especially dural tears and spinal cord injury, can also be effectively controlled.

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.

Microendoscopic Posterior Decompression for Treating Thoracic Myelopathy Caused by Ossification of the Ligamentum Flavum: Case Series

Background and Objectives: Ossification of the ligamentum flavum (OLF) is a relatively common cause of thoracic myelopathy. Surgical treatment is recommended for patients with myelopathy. Generally, open posterior decompression, with or without fusion, is selected to treat OLF. We performed minimally invasive posterior decompression using a microendoscope and investigated the efficacy of this approach in treating limited type of thoracic OLF. Materials and Methods: Microendoscopic posterior decompression was performed for 19 patients (15 men and four women) with thoracic OLF with myelopathy aged between 35 to 81 years (mean age, 61.9 years). Neurological examination and preoperative magnetic resonance imaging (MRI) and computed tomography (CT) were used to identify the location and morphology of OLF. The surgery was performed using a midline approach or a unilateral paramedian approach depending on whether the surgeon used a combination of a tubular retractor and endoscope. The numerical rating scale (NRS) and modified Japanese Orthopedic Association (mJOA) scores were compared pre- and postoperatively. Perioperative complications and the presence of other spine surgeries before and after thoracic OLF surgery were also investigated. Results: Four midline and 15 unilateral paramedian approaches were performed. The average operative time per level was 99 min, with minor blood loss. Nine patients had a history of cervical or lumbar spine surgery before or after thoracic spine surgery. The mean pre- and postoperative NRS scores were 6.6 and 5.3, respectively. The mean recovery rate as per the mJOA score was 33.1% (mean follow-up period, 17.8 months), the recovery rates were significantly different between patients who underwent thoracic spine surgery alone (50.5%) and patients who underwent additional spine surgeries (13.7%). Regarding adverse events, one patient experienced dural tear, another experienced postoperative hematoma, and one other underwent reoperation for adjacent thoracic stenosis. Conclusion: Microendoscopic posterior decompression was applicable in limited type of thoracic OLF surgery including beak-shaped type and multi vertebral levels. However, whole spine evaluation is important to avoid missing other combined stenoses that may affect outcomes.

Full-endoscopic decompression for thoracic ossification of ligamentum flavum: surgical techniques and clinical outcomes: A retrospective clinical study

BACKGROUND

Many complications are associated with thoracic open decompression surgery, such as dural tears and neurological deficits. The clinical outcomes are also not satisfactory. Full-endoscopic decompression of the lumbar spinal canal has achieved satisfactory results for the treatment of lumbar spinal stenosis. This surgery may be used for the treatment of thoracic ossification of the ligamentum flavum (OLF) under local anesthesia. The aim of our study is to introduce the surgical techniques used for full-endoscopic decompression for thoracic OLF and to evaluate its safety and efficacy.

METHODS

Fourteen patients with thoracic OLF (4 combined with dural ossification) underwent full-endoscopic decompression surgery. An interlaminar approach was performed. The anchoring method was used to establish the working passage. Spinal cord exposure began at a space between the ossification and the spinal cord, and dorsal and contralateral decompression were performed with the "Over the Top" technique. The modified Japanese Orthopedic Association score (11 points) was used to evaluate the efficacy during follow-up. At the same time, the visual analogue scale score for assessing back pain before and after the operation was evaluated.

RESULTS

The average operation time was 159.73 ± 62.09 minutes, and the hospitalization time was 7.43 ± 1.79 days. The follow-up period ranged from 8 to 22 months. Neurological function was improved. There were no serious complications. Dural tears occurred in 5 patients, intraoperative neurological deterioration occurred in 1 patient, and intraoperative headache and neck pain occurred in 1 patient.

CONCLUSION

Full-endoscopic decompression is an effective, safe surgical technique for thoracic OLF even the cases combined with dural ossification.

Thin Cervical Spinal Cord Between Ossifications of the Ligamentum Flavum and the Posterior Longitudinal Ligament: Case Report and Literature Review

BACKGROUND

Cervical ossification of the ligamentum flavum (OLF) is a rare condition; however, the coexistence of OLF and ossification of the posterior longitudinal ligament (OPLL) is extremely uncommon. These can exist simultaneously and cause thinning of the cervical spinal cord. Sufficient decompression, dural ossification, semispinalis dissection, and postoperative kyphosis were evaluated. We report the successful treatment of coexisting cervical OLF and OPLL.

CASE DESCRIPTION

A 70-year-old man had been experiencing weakness in the left knee and clumsiness in the left hand for 6 months. Hemiparesis was considered; however, magnetic resonance imaging revealed a cervical spinal lesion. Hence a spine surgeon diagnosed the patient with severe stenosis with OLF at the C2-C3 levels and OPLL at the C2-C4 levels. The patient presented with spastic gait and left-hand motor weakness. Computed tomography scan revealed the disappearance of the black line, indicating dural ossification surrounding the OLF. OPLL was observed in 61.5% of the C2 spinal canal. The K-line was (-); however, the alternative K-line between the C1 and C7 level was (+). Posterior laminectomy at the C2-C3 levels and laminoplasty at the C4-C7 levels with muscle preservation resulted in sufficient decompression. The patient's symptoms improved, and cervical alignment was maintained 2 years after surgery.

CONCLUSIONS

An alternative K-line comprised successful treatment for coexisting cervical OLF and OPLL. Surgeons must evaluate the severity of adhesion, damage of the paraspinal muscles, and necessity of posterior corrective surgery along with the patient's comorbidities and possible postoperative complications.

The Role of JAK-STAT Signaling Activation in Hypertrophied Ligamentum Flavum

BACKGROUND

Although previous studies have reported the expression of JAK1, STAT3, and phosphorylated STAT3 in hypertrophied ligamentum flavum (LF), the role of the Janus kinase-signal transducer and activator of transcription (JAK/STAT) signaling pathway in hypertrophied LF has not been fully elucidated. The aim of this study was to identify the important JAK/STAT gene expression patterns of the 3 main receptors involved in this pathway: interferon (IFN)-γ receptor (IFN-γR), IFN-α receptor (IFNAR), and interleukin (IL)-6 receptor (IL-6R).

METHODS

The human LF specimens were obtained from 28 patients who underwent lumbar spine surgery for either degenerative lumbar canal stenosis (DLCS) (n = 28) or lumbar disc herniation (LDH) (n = 20). In this design, patients with LDH served as the control group. The degree of fibrosis was demonstrated by Masson's trichrome staining. The location and expression profiling of the JAK/STAT pathway were analyzed by quantitative real-time polymerase chain reaction and Western blotting. The thickness of the LF was measured with axial T1-weighted magnetic resonance imaging.

RESULTS

The most severe fibrotic changes were on the dorsal side of the LF. IL-6 and IFN-I expression levels were significantly increased on the dorsal side of the LF. While expression levels of IL-6R and IFNAR on the dural and dorsal side were significantly higher in the DLCS samples, IFN-γR and endothelial epidermal growth factor receptor in LF samples showed a significant increase only on the dorsal side. JAK/STAT genes were significantly expressed, especially on the dorsal side.

CONCLUSIONS

Our data suggest that IFNAR- and IL-6R-dependent JAK/STAT signaling pathways may be significant targets in drug development strategies for the treatment of LF hypertrophy.

Endoscope-Assisted Minimally Invasive Interlaminar Lumbar Decompression for Spinal Stenosis

BACKGROUND

Lumbar stenosis is characterized by a narrowing of the spinal canal in association with progressive degenerative changes in the lumbar spine and surrounding structures, including hypertrophy of the ligamentum flavum (LF).

OBJECTIVES

The aim of this study was to examine the usefulness of endoscope-assisted interlaminar lumbar decompression (EILD) for patients with lumbar stenosis and hypertrophy of the LF.

STUDY DESIGN

Retrospective study.

SETTING

Department of Anesthesiology and Pain Medicine, Neurosurgery at Wooridul Spine Hospital.

METHODS

A total of 51 patients were enrolled in this study. Outcomes were evaluated at baseline and at 2 weeks and 6 months postprocedure via the Numeric Rating Scale, Oswestry Disability Index (ODI), and Zurich Claudication Questionnaire (ZCQ).

RESULTS

Mean posttreatment pain scores at 2 weeks and 6 months were significantly lower, and ODI scores were significantly decreased compared with baseline. ZCQ scores were also significantly decreased compared with pretreatment surveys. Two patients required reoperation within one month. At postprocedure 6 months, a>/= 50% reduction in pain score was recorded in 26 (80%) of 51 patients, and there was >/= 40% reduction in ODI score in 82% of patients. No serious complications including epidural bleeding, dural or neural injuries, or infection were recorded.

LIMITATIONS

This study lacked secondary outcome substantiation. In addition, the follow-up period was short (< 6 months), and no patients had postprocedure magnetic resonance imaging. The number of patients was also small.

CONCLUSIONS

EILD provided good outcomes and may be a reasonable treatment option for carefully selected patients with hypertrophy of the LF.

KEY WORDS

Spinal stenosis, ligamentum flavus, hypertrophy, decompression, endoxcope, minimally.

Rapidly Progressing Symptomatic Calcification of Ligamentum Flavum in Thoracic Spine After Osteoporotic Vertebral Fractures

BACKGROUND

Symptomatic calcification of the ligamentum flavum (CLF) is common in the cervical spine but rare in the thoracic spine. Rapidly progressing CLF in the thoracic spine has not been reported in the literature.

CASE DESCRIPTION

A 76-year-old Asian male experienced back pain after a fall and was diagnosed with osteoporotic vertebral fractures at T11 and L1. He was treated conservatively because of the lack of neurologic deficits. Nine months after the initial visit, he complained of progressive incomplete paraplegia. Magnetic resonance imaging and computed tomography of the thoracic spine showed CLF at T11-T12 severely compressing the spinal cord. This finding had not been seen on imaging studies at the initial visit. The patient underwent surgical resection of CLF and posterior instrumented spine fusion. Symptoms of muscle weakness recovered postoperatively.

CONCLUSIONS

In this case, sequential imaging studies with a 9-month interval showed evidence of rapidly progressing thoracic CLF. The preceding osteoporotic vertebral fracture may have triggered the development of CLF.

Benefits and Risks of Subsection Laminectomy with Pedicle Screw Fixation for Ossification of the Ligamentum Flavum of the Thoracic Spine: A Retrospective Study of 30 Patients

BACKGROUND This study aimed to evaluate the effectiveness of subsection laminectomy with pedicle screw fixation (SLPF) for the treatment of ossification of the ligamentum flavum of the thoracic spine. MATERIAL AND METHODS Thirty patients (age, 40-71 years) with ossification of the ligamentum flavum of the thoracic spine underwent SLPF (13 men, 17 women). Operative time, intraoperative blood loss, preoperative and postoperative change in thoracic kyphosis, and perioperative complications were recorded. The Japanese Orthopedic Association (JOA) score for severity of myelopathy and the American Spinal Injury Association (ASIA) motor and sensory impairment scale were used before and after surgery. RESULTS Mean operative time for SLPF was 208.4±38.3 min and mean intraoperative blood loss was 689.3±171.7 ml. The mean JOA score significantly increased from 5.7±1.9 before surgery to 8.8±2.2 at one month after surgery and 9.3±2.7 at the last follow-up (P<0.01). Postoperative improvement in neurological function increased by 68.3±14.4%. The postoperative ASIA grades significantly improved compared with the preoperative grades (P<0.01). The mean local Cobb angle significantly decreased from 17.8±4.3° before surgery to 15.4±3.6° at one month after surgery and 15.8±3.8° at the last follow-up (P<0.01). Three patients (10%) had operative cerebrospinal fluid (CSF) leak. Postoperatively, one patient had neurological deterioration, two patients had deep venous thrombosis (DVT), and one patient developed a wound infection. CONCLUSIONS SLPF was an effective procedure for the treatment of ossification of the ligamentum flavum of the thoracic spine.

Decreased catalase expression is associated with ligamentum flavum hypertrophy due to lumbar spinal canal stenosis

BACKGROUND

This is an immunohistologic study of gene expression between patients and controls.This study aims to evaluate expression of the catalase gene in hypertrophied ligamentum flavum (LF) specimens obtained from patients with lumbar spinal canal stenosis (LSCS).LSCS is one of the most common spinal disorders. It is well known that LF hypertrophy plays an important role in the onset of LSCS. Although degenerative changes, aging, and mechanical stress are all thought to contribute to hypertrophy and fibrosis of the LF, the precise pathogenesis of LF hypertrophy remains unknown. Previous genetic studies have tried to determine the mechanism of LF hypertrophy. However, the association between catalase gene expression and LF hypertrophy has not yet been explored.

METHODS

LF specimens were surgically obtained from 30 patients with spinal stenosis (LSCS group) and from 30 controls with lumbar disc herniation (LDH group). LF thickness was measured at the thickest point using calipers to an accuracy of 0.01 mm during surgical intervention. The extent of LF elastin degradation and fibrosis were graded (grades 0-4) by hematoxylin and eosin staining and Masson trichrome staining, respectively. The resulting LF measurements, histologic data, and immunohistologic results were then compared between the 2 groups.

RESULTS

The average LF thickness was significantly higher in the LSCS group than in the LDH group (5.99 and 2.95 mm, respectively, P = .004). Elastin degradation and fibrosis of the LF were significantly more severe in spinal stenosis samples than in the disc herniation samples (3.04 ± 0.50 vs 0.79 ± 0.60, P = .007; 3.01 ± 0.47 vs 0.66 ± 0.42, P = .009, respectively). Significantly lower expression of catalase was observed in the perivascular area of LF samples obtained from patients with LSCS compared with controls (61.80 ± 31.10 vs 152.80 ± 41.13, respectively, P = .009).

CONCLUSION

Our findings suggest that decreased expression of catalase is associated with LF hypertrophy in patients with LSCS.

Angiopoietin-2 promotes osteogenic differentiation of thoracic ligamentum flavum cells via modulating the Notch signaling pathway

Thoracic ossification of the ligamentum flavum (TOLF) is heterotopic ossification of spinal ligaments, which may cause serious thoracic spinal canal stenosis and myelopathy. However, the underlying etiology remains inadequately understood. In this study, the ossification patterns of TOLF were analyzed by micro-computer tomography (micro-CT). The expression profile of genes associated with angiogenesis was analyzed in thoracic ligamentum flavum cells at sites of different patterns of ossification using RNA sequencing. Significant differences in the expression profile of several genes were identified from Gene Ontology (GO) analysis. Angiopoietin-2 (ANGPT2) was significantly up-regulated in primary thoracic ligamentum flavum cells during osteogenic differentiation. To address the effect of ANGPT2 on Notch signaling and osteogenesis, ANGPT2 stimulation increased the expression of Notch2 and osteogenic markers of primary thoracic ligamentum flavum cells of immature ossification, while inhibition of ANGPT2 exhibited opposite effect on Notch pathway and osteogenesis of cells of mature ossification. These findings provide the first evidence for positive regulation of ANGPT2 on osteogenic differentiation in human thoracic ligamentum flavum cells via modulating the Notch signaling pathway.

Pathophysiology of Calcification and Ossification of the Ligamentum Flavum in the Cervical Spine

Calcification of the ligamentum flavum (CLF) and ossification of the ligamentum flavum (OLF) in the cervical spine are differential diagnoses in patients with posterior extradural compressive lesions related to cervical degenerative disease. Preoperative computed tomography can facilitate the detection of characteristic findings and help to distinguish between CLF and OLF. Although these are rare entities in the cervical spine, adequately timed surgical decompression is required in most patients who present with radiculomyelopathy.

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.

Eight years of follow-up after laminectomy of calcium pyrophosphate crystal deposition in the cervical yellow ligament of patient with Coffin-Lowry syndrome: A case report

BACKGROUND

We report 8 years of follow-up after decompression to treat cervical myelopathy in a patient with Coffin-Lowry syndrome (CLS). CLS is a rare X-linked semidominant syndrome associated with growth and psychomotor retardation, general hypotonia, and skeletal abnormalities. In this patient, the spinal cord was compressed by calcium pyrophosphate crystal deposition in the cervical yellow ligament (YL). To date, only 1 report has described clinical features after surgery for calcified cervical YL in CLS.

METHODS

A 15-year-old male with tetraplegia secondary to compression of the cervical spinal cord induced by a hypoplastic posterior arch of C1 and calcification of the YL from C2 to C7 was treated surgically with laminectomy from C1 to C7. The patient's history, clinical examination, imaging findings, and treatment are reported. The patient was incapable of speech because of mental retardation, so he could not describe his symptoms. Gait disturbance worsened over the 2 months before admission to our hospital. At admission, the patient could not move his extremities, and tendon reflexes of the upper and lower extremities were significantly increased. Computed tomography of the cervical spine showed YL calcification from C2 to C7. Magnetic resonance imaging showed consecutive compression of the cervical spinal cord. We diagnosed quadriplegia secondary to cervical cord damage and performed emergency surgery.

RESULTS

During C1-C7 laminectomy, YL calcification in C2-C7 was observed. The calcification was confirmed as calcium pyrophosphate by crystal analysis. Quadriplegia gradually resolved, and almost disappeared by 2 weeks after the operation. Cervical hyperlordosis was observed in radiographs starting from 1 month after the operation, but it has not progressed and is not associated with any symptoms.

CONCLUSIONS

The efficacy of decompression continued, and no postoperative complications have occurred during at least 8 years of follow-up.

Ablation of porcine ligamentum flavum with Ho:YAG, q-switched Ho:YAG, and quadrupled Nd:YAG lasers

BACKGROUND AND OBJECTIVES

Ligamentum flavum (LF) is a tough, rubbery connective tissue providing a portion of the ligamentous stability to the spinal column, and in its hypertrophied state forms a significant compressive pathology in degenerative spinal stenosis. The interaction of lasers and this biological tissue have not been thoroughly studied. Technological advances improving endoscopic surgical access to the spinal canal makes selective removal of LF using small, flexible tools such as laser-coupled fiber optics increasingly attractive for treatment of debilitating spinal stenosis. Testing was performed to assess the effect of Ho:YAG, Q-switched Ho:YAG, and frequency quadrupled Nd:YAG lasers on samples of porcine LF. The objective was to evaluate the suitability of these lasers for surgical removal of LF.

STUDY DESIGN/MATERIALS AND METHODS

LF was resected from porcine spine within 2 hours of sacrifice and stored in saline until immediately prior to laser irradiation, which occurred within an additional 2 hours. The optical absorbance of a sample was measured over the spectral band from 190 to 2,360 nm both before and after dehydration. For the experiments using the Ho:YAG (λ = 2,080 nm, tp  = 140 µs, FWHM) and Q-Switched Ho:YAG (λ = 2,080 nm, tp  = 260 ns, FWHM) lasers, energy was delivered to the LF through a laser-fiber optic with 600 µm core and NA = 0.39. For the experiment using the frequency quadrupled Nd:YAG laser (λ = 266 nm, tp  = 5 ns FWHM), rather than applying the laser energy through a laser-fiber, the energy was focused through an aperture and lens directly onto the LF. Five experiments were conducted to evaluate the effect of the given lasers on LF. First, using the Ho:YAG laser, the single-pulse laser-hole depth versus laser fluence was measured with the laser-fiber in direct contact with the LF (1 g force) and with a standoff distance of 1 mm between the laser-fiber face and the LF. Second, with the LF remaining in situ and the spine bisected along the coronal plane, the surface temperature of the LF was measured with an IR camera during irradiation with the Ho:YAG laser, with and without constant saline flush. Third, the mass loss was measured over the course of 450 Ho:YAG pulses. Fourth, hole depth and temperature were measured over 30 pulses of fixed fluence from the Ho:YAG and Q-Switched Ho:YAG lasers. Fifth, the ablation rate and surface temperature were measured as a function of fluence from the Nd:YAG laser. Several LF staining and hole-depth measurement techniques were also explored.

RESULTS

Aside from the expected absorbance peaks corresponding to the water in the LF, the most significant peaks in absorbance were located in the spectral band from 190 to 290 nm and persisted after the tissue was dehydrated. In the first experiment, using the Ho:YAG laser and with the laser-fiber in direct contact with the LF, the lowest single-pulse fluence for which LF was visibly removed was 35 J/cm(2) . Testing was conducted at 6 fluences between 35 and 354 J/cm(2) . Over this range the single-pulse hole depth was shown to be near linear (R(2)  = 0.9374, M = 1.6), ranging from 40 to 639 µm (N = 3). For the case where the laser-fiber face was displaced 1 mm from the LF surface, the lowest single-pulse fluence for which tissue was visibly removed was 72 J/cm(2) . Testing was conducted at 4 energy densities between 72 and 180 J/cm(2) . Over this range the single-pulse hole depth was shown to be near linear (R(2)  = 0.8951, M = 1.4), ranging from 31 to 220 µm (N = 3). In the second experiment, with LF in situ, constant flushing with room temperature saline was shown to drastically reduce surface temperature during exposure to Ho:YAG at 5 Hz with the laser-fiber in direct contact with the LF. Without saline, over 1 minute of treatment with a per-pulse fluence of 141 mJ/cm(2) , the average maximum surface temperature measured 110°C. With 10 cc's of saline flushed over 1 minute and a per-pulse laser fluence of 212 mJ/cm(2) , the average maximum surface temperature was 35°C. In the third experiment, mass loss was shown to be linear over 450 pulses of 600 mJ from the Ho:YAG laser (212 J/cm(2) , direct contact, N = 4; 108 J/cm(2) , 1 mm standoff, N = 4). With the laser-fiber in direct contact, an average of 53 mg was removed (R(2)  = 0.996, M = 0.117) and with 1 mm laser-fiber standoff, an average of 44 mg was removed (R(2)  = 0.9988, M = 0.097). In the fourth experiment, 30 pulses of the Ho:YAG and Q-Switched Ho:YAG lasers at 1 mm standoff, and 5 Hz produced similar hole depths for the tested fluences of 9 J/cm(2) (151 and 154 µm, respectively) and 18 J/cm(2) (470 and 442 µm, respectively), though the Ho:YAG laser produced significantly more carbonization around the rim of the laser-hole. The increased carbonization was corroborated by higher measured LF temperature. In all tests with the Ho:YAG and Q-Switched Ho:YAG, an audible photo-acoustic affect coincided with the laser pulse. In the fifth experiment, with the frequency quadrupled Nd:YAG laser at 15 Hz for 450 pulses, ablation depth per pulse was shown to be linear for the fluence range of 0.18 - 0.73 J/cm(2) (R(2)  = 0.989, M = 2.4). There was no noticeable photo-acoustic effect nor charring around the rim of the laser-hole.

CONCLUSION

The Ho:YAG, Q-Switched Ho:YAG, and frequency quadrupled Nd:YAG lasers were shown to remove ligamentum flavum (LF). A single pulse of the Ho:YAG laser was shown to cause tearing of the tissue and a large zone of necrosis surrounding the laser-hole. Multiple pulses of the Ho:YAG and Q-Switched Ho:YAG lasers caused charring around the rim of the laser-hole, though the extent of charring was more extensive with the Ho:YAG laser. Charring caused by the Ho:YAG laser was shown to be mitigated by continuously flushing the affected LF with saline during irradiation. The Nd:YAG laser was shown to ablate LF with no gross visible indication of thermal damage to surrounding LF.

Laminoplasty and laminectomy hybrid decompression for the treatment of cervical spondylotic myelopathy with hypertrophic ligamentum flavum: a retrospective study

OBJECTIVE

To report the outcomes of a posterior hybrid decompression protocol for the treatment of cervical spondylotic myelopathy (CSM) associated with hypertrophic ligamentum flavum (HLF).

BACKGROUND

Laminoplasty is widely used in patients with CSM; however, for CSM patients with HLF, traditional laminoplasty does not include resection of a pathological ligamentum flavum.

METHODS

This study retrospectively reviewed 116 CSM patients with HLF who underwent hybrid decompression with a minimum of 12 months of follow-up. The procedure consisted of reconstruction of the C4 and C6 laminae using CENTERPIECE plates with spinous process autografts, and resection of the C3, C5, and C7 laminae. Surgical outcomes were assessed using Japanese Orthopedic Association (JOA) score, recovery rate, cervical lordotic angle, cervical range of motion, spinal canal sagittal diameter, bone healing rates on both the hinge and open sides, dural sac expansion at the level of maximum compression, drift-back distance of the spinal cord, and postoperative neck pain assessed by visual analog scale.

RESULTS

No hardware failure or restenosis was noted. Postoperative JOA score improved significantly, with a mean recovery rate of 65.3 ± 15.5%. Mean cervical lordotic angle had decreased 4.9 degrees by 1 year after surgery (P<0.05). Preservation of cervical range of motion was satisfactory postoperatively. Bone healing rates 6 months after surgery were 100% on the hinge side and 92.2% on the open side. Satisfactory decompression was demonstrated by a significantly increased sagittal canal diameter and cross-sectional area of the dural sac together with a significant drift-back distance of the spinal cord. The dural sac was also adequately expanded at the time of the final follow-up visit.

CONCLUSION

Hybrid laminectomy and autograft laminoplasty decompression using Centerpiece plates may facilitate bone healing and produce a comparatively satisfactory prognosis for CSM patients with HLF.

Computer-assisted minimally invasive spine surgery for resection of ossification of the ligamentum flavum in the thoracic spine

BACKGROUND

Ossification of the ligamentum flavum (OLF) has been widely recognized as one of the main causes of thoracic spinal canal stenosis and thoracic myelopathy. Decompression is the only effective strategy for treating thoracic myelopathy caused by OLF. The purpose of this study was to describe the clinical outcomes of computer-assisted minimally invasive spine surgery (CAMISS) for posterior decompression in patients with thoracic myelopathy caused by OLF.

METHODS

In all cases, the surgical procedure was performed with the assistance of an intraoperative three-dimensional navigation system. Decompression of the spinal cord was performed with a high-speed drill; the supraspinal ligaments and spinous process were partially preserved. The outcomes were evaluated by a modified Japanese Orthopedic Association (JOA) scoring system and recovery rates.

RESULTS

The mean duration of follow-up for the 14 cases was 3.9 years. All patients experienced neurological recovery, the mean JOA score improving from 6.1 points preoperatively to 8.6 points at final follow-up and the mean rate of recovery being 52.7% (excellent in two cases, good in eight, fair in three, and unchanged in one).

CONCLUSION

CAMISS is a safe and effective procedure for resection of the OLF in the thoracic spine.

Clinical results and intramedullary signal changes of posterior decompression with transforaminal interbody fusion for thoracic myelopathy caused by combined ossification of the posterior longitudinal ligament and ligamentum flavum

BACKGROUND

Surgical treatment of thoracic myelopathy caused by ossification of the posterior longitudinal ligament (OPLL) and ossification of the ligamentum flavum (OLF) is technically demanding, and the results tend to be unfavorable. Various operative approaches and treatment strategies have been attempted, and posterior decompression with transforaminal thoracic interbody fusion (PTTIF) may be the optimal method with which the anterior-posterior compression was removed in one step. It is comparatively less traumatic with fewer serious complications.

METHODS

Sixteen patients with thoracic myelopathy due to concurrent OLF and OPLL at the same level underwent PTTIF. We investigated clinical outcomes and neurological improvements. Magnetic resonance imaging (MRI) was performed on all patients preoperatively and postoperatively, and intramedullary signal changes were evaluated.

RESULTS

The mean operating time was 275 minutes, and the mean operative bleeding amount was 1031 ml. Cerebrospinal fluid leakage occurred in three patients and healed well after repair. Neurological symptom deterioration occurred in one patient, but the patient recovered to nearly the preoperative level after methylprednisolone treatment. The follow-up period ranged from 28 to 47 months. The mean score on the Japanese Orthopedic Association scale improved from 4.3±1.2 preoperatively to 7.3±1.7 at 3 months postoperatively to 8.5±1.5 at the final follow-up (P < 0.01), with a recovery rate of (63.6±20.0)%. Postoperative images showed a significant improvement in local kyphosis (P < 0.01). Eleven patients (68.8%) showed increased signal intensity (ISI) on preoperative T2-weighted MRI. At the final follow-up, the intramedullary ISI totally recovered in five patients. Neurological improvement was worse in patients with persistent ISI than in the other patients (P < 0.05).

CONCLUSIONS

PTTIF is an effective therapeutic option for combined OPLL and OLF and provides satisfactory neurological recovery and stabilized thoracic fusion through a single posterior approach. Intramedullary signal changes do not always indicate a poor prognosis; only irreversible ISI is correlated with a poor clinical result.

[Imaging analysis of ossification of ligamentum flavum associated with dural adhesions]

OBJECTIVE

To summarize the characteristic imaging signs of ossification of the ligamentum flavum (OLF) associated with dural adhesions by analyzing retrospectively the imaging signs of OLF associated with dural adhesions.

METHODS

A retrospective analysis was made on clinical data of 85 patients undergoing OLF surgery between January 2010 and September 2012. The patients were assigned into the study group and the control group according to the preoperative imaging signs. Of 85 patients, 34 had both "tram track sign" and "jagged line sign" as the study group and 51 had either "tram track sign" or "jagged line sign" and neither of them as the control group. Adherence between dura mater and ligamentum flavum was observed during operation as the "gold standard" for the diagnosis of dural adhesion. The imaging information of CT and MRI in sagittal and axial planes was analyzed. The typical characteristics of dural adhesions were found. Then the sensitivity, specificity, and positive likelihood ratio of the preoperative imaging examinations were calculated to estimate the reference value and diagnostic value (> 5 having reference value, and > 10 having diagnostic value).

RESULTS

In the study group, dural adhesion was observed in 26 patients (10 males and 16 females), and the other 8 patients (6 males and 2 females) had no dural adhesion. In the control group, dural adhesion was found in 2 female patients who had "jagged line sign", and 49 patients had no dural adhesion (14 males and 35 females). In patients having both "tram track sign" and "jagged line sign", the sensitivity was 92.9%; the specificity was 86.0%; and the positive likelihood ratio was 6.6. In patients having "tram track sign", the sensitivity was 92.9%; the specificity was 64.9%; and the positive likelihood ratio was 2.6. In patients having "jagged line sign", the sensitivity was 100%; the specificity was 77.2%; and the positive likelihood ratio was 4.4.

CONCLUSION

For patients with OLF having both "tram track sign" and "jagged line sign", preoperative CT and MRI have a reference value for diagnoses of the OLF associated with dural adhesions.

Thoracic spinal stenosis and myelopathy: report of two rare cases and review of the literature

The authors report two cases of thoracic spinal canal stenosis (SCS) and myelopathy. One is extremely unusual because of degenerative changes occurred in the upper thoracic spine. The other because of its multiple etiology among which calcification and ossification of the ligamentum flavum (OLF) in a Caucasian man. Both patients presented with an history of slowly progressive spastic paraparesis. In the first case computed tomography (CT) scans and magnetic resonance (MR) images revealed hypertrophy of the legamentum flavum and laminae causing compression of the spinal cord at T2-T3. In the second case diagnostic imaging showed three levels of stenosis in the lower thoracic spine due to degenerative changes, calcification and OLF with cord damage at T9-T10. A decompressive laminectomy and medial facetectomy was performed in both patients. The ligamentum flavum, hypertrophied and infolded in the first case and calcified and ossified in the second, was removed with careful dissection of the dural adhesions. Both patients showed a rapid post-operative recovery and regained autonomous walking within 1 month of surgery. Thoracic spinal cord stenosis is a rare and complex disorder because of differential diagnosis, neuroimaging features and treatment options. Regardless of its cause, prompt surgical decompression plays a key role in improving the functional outcome of myelopathy.

[Surgical treatment of ossification of ligamentum flavum in thoracic spine and its therapeutic effect analysis]

OBJECTIVE

To explore the correlation between CT classification and operative method and to discuss its therapeutic effect.

METHODS

From January of 2001 to June of 2010, 30 patients with thoracic ossification of ligamentum flavum were reviewed retrospectively, including 22 males and 8 females with an average age of 52.8 years old (ranged from 37 to 68 years old). The course of duration ranged from 2 months to 6 years. Single segment lesion was in 11 cases and multiple segments were in 19 cases. Two patients were accompanied by cervical ossification of ligamentum flavum and 1 was accompanied by ossification of posterior longitudinal ligament. The ossified lesions were located at T1,2 to T4,5 in 5 cases,T5,6 to T8,9 in 7 cases, T9,10 to T11,12 in 12 cases, at the upper and middle thoracic levels in 2 cases, at the middle and lower thoracic levels in 4 cases. They were divided into 2 types according to the morphologic features of the CT scan:simple type, 18 segments with lateral, slice or unfused type; complex type, 42 segments with thickened, fused or nodular type. The clinical manifestation was paralysis of upper motor neuron in 21 cases, and of upper and lower motor neuron in other 9 cases. Sphincter dysfunction was found in 26 cases. Preoperative JOA sphincter function score was 1.97 +/- 0.56. Preoperative modified JOA motor function score of lower limb was 1.20 +/- 0.76. Different surgical procedure was applied to one of the 2 types. For the simple type, an en bloc laminectomy was performed. However,for the complex type, a laminar shelling decompression was done. Laminectomy combined with internal fixation and lateral fusion was performed in patients whose decompressive areas were wider.

RESULTS

The mean decompression length was 3.1 lamina (2 to 6 lamina). Cerebrospinal fluid leakage was found in 3 cases and hematoma in incision was found in 1 case. The mean follow-up duration was 26 months (12 to 96 months). Twenty-two patients with the feel of constriction of trunk or lower limbs were completely recovered; 18 cases with sensation disturbance, numbness and pain of the lower limb were totally recovered, and relived in 10 cases. Postoperative JOA sphincter function score was 2.73 +/- 0.45, comparing with the preoperative score, and the difference was significant (P < 0.01). Postoperative JOA motor function score was 3.57 +/- 0.77, comparing with the preoperative score, and the difference was significant (P < 0.01 ). The lower limb function relief rate was 86.1%, 24 patients got an excellent results, 3 good, 2 poor and 1 bad.

CONCLUSION

Different surgical procedures will be safely and effectively applied to treat thoracic ossification of ligamentum flavum according to CT classification.

[Longterm outcome after the decompressive surgery for thoracic myelopathy due to the ossification of the ligamentum flavum]

OBJECTIVES

To investigate the long-term surgical outcome of thoracic myelopathy caused by the ossification of the ligamentum flavum (OLF) and evaluate the related risk factors.

METHODS

Forty-four patients who underwent decompressive laminectomy with thoracic OLF between January 1990 and December 2005 and got more than 5 years follow-up were retrospectively reviewed. Among these 44 cases, there were 29 male and 15 female whose ages at operation were 52 years averagely (27-68 years). The 2-year follow-up results and long-term outcomes were classified according to the modified Epstein's standard, and then the rates of excellent or good (REG) were calculated. The correlation between the long-term REG and the patients' ages, durations of symptoms, decompressed levels, and dural leak were analyzed.

RESULTS

The mean follow-up period of these 44 cases was 8.5 years (5-19 years). The REG at 2 years after laminectomy was 77.3% (34/44), while the long-term REG was 65.9% (29/44). There was one case who had suffered from an acute spinal cord injury got a poor post-operative outcome. The other 43 cases had chronic durations, including 22 cases whose pre-operative durations of symptoms were less than 12 months and 21 cases whose durations were equal to or more than 12 months. And the long-term REG of these two groups were 77.3% (17/22) and 57.1% (12/21) respectively (P>0.05). The REG of those cases whose decompression levels were limited in T1-T9 was 78.9% (15/19), while that of those cases whose laminectomy was relevant to thoracolumbar segment (T10-L2) was 58.3% (14/24) (P>0.05). There were 7 cases who had excellent or good short-term results and poor long-term outcomes. The reasons of these changes included coexistence of lumbar spinal stenosis in three cases and the growth of the OLF at the adjacent levels in four cases.

CONCLUSIONS

Although the short-term results of the decompressive surgery for thoracic OLF is good, the regular long-term follow-up is necessary because the symptoms may reoccur or deteriorate secondary to lumbar spinal stenosis or the growth of OLF at the adjacent levels near former decompressive levels; the duration of symptoms which is more than one year and the decompression levels that is involved to T10-L2 segments are possibly related to the poor long-term outcomes.

[Surgery tactics for ossification of ligamentum flavum associated with dural ossification in the thoracic spine]

OBJECTIVE

To investigate the surgery tactics for ossification of ligamentum flavum (OLF) associated with dural ossification (DO) in the thoracic spine and the clinical outcome.

METHODS

Between June 2006 and December 2009, 98 patients with thoracic spinal stenosis secondary to OLF were treated, and DO was found in 18 cases during operation. There were 11 males and 7 females with a mean age of 58 years (range, 46-73 years). The disease duration ranged from 5 to 48 months (mean, 20 months). All patients underwent surgical decompression because of recent neurological aggravation. Both DO and OLF were resected with octagonal decompression by dissecting pedicle flavum tunnel. The Japanese Orthopaedic Association (JOA) score, modified Oswestry Disability Index (ODI), and the Cobb angle were used to evaluate the effectiveness.

RESULTS

The initial symptoms were significantly alleviated postoperatively. All patients had transient cerebrospinal fluid (CSF) leakage postoperatively, the CSF leakage disappeared after 8-10 days of conservative treatment. All the incisions healed by first intention. There was no complication of neurologic function deterioration, meningitis, wound infection, or spinocutaneous fistula. Eighteen patients were followed up 20-60 months (mean, 49 months). No recurrence of spinal cord compression symptoms, or neurologic function deterioration was observed at last follow-up. The JOA scores and effectiveness and modified ODI scores were significantly improved after 1 month and 12 months of operation when compared with preoperative scores (P < 0.05). The Cobb angles of kyphosis of the involved vertebrae were (6.7 +/- 1.6) degrees before operation and (8.0 +/- 1.2) degrees after 12 months of operation, showing significant difference (t = 4.000, P = 0.001). Postoperative T2-weighted axial MRI, sagittal MRI scan, and short T1 inversion recovery MRI showed that compressed deformity of the spinal cord returned to normal.

CONCLUSION

The surgery tactics for thoracic spinal stenosis secondary to the OLF with DO is safe, and no patching dura mater tears is effective.

Spinal cord compression by hematoma in the cervical ligamentum flavum: a case report

BACKGROUND CONTEXT

There have been some reports describing hematoma in the thoracic and lumbar ligamentum flavum, but there have been only three reports of hematoma in the cervical ligamentum flavum.

PURPOSE

We describe another case of the ligamentum flavum hematoma in the cervical spine with a different feature of occurrence that required surgical treatment.

STUDY DESIGN

Case report.

PATIENT SAMPLE

Patient with ligamentum flavum hematoma in the cervical spine.

OUTCOME MEASURES

Preoperative magnetic resonance imaging and pathologic finding from operative specimen confirmed the diagnosis.

METHODS

A 69-year-old man insidiously presented with pain in his left upper arm and difficulty in left shoulder abduction. Neurologic examination demonstrated a cervical myelopathy with diffuse muscle weakness of left upper extremity and sensory disturbance. Imaging studies revealed a mass of high intense on T1-weighted images and isointense on T2-weighted images posterior to the dura at C4 lower end level. The patient underwent C4-C5 hemilaminectomy and the removal of the mass. The mass existed within the ligamentum flavum and was connected toward the pedicle like the beads of a rosary.

RESULTS

Histopathologic examination of the surgical specimen showed that the hematoma was present within the ligamentum flavum and contained macrophages that had phagocytosed red blood cells and hemosiderin. After surgery, the patients' symptoms immediately improved, and no recurrence was observed at 2 years postoperatively.

CONCLUSIONS

We reported a very rare case of hematoma in the ligamentum flavum of the cervical spine that required surgery. Because the patient was without the history of trauma, it was suggested that the use of antiplatelet drugs was responsible for the occurrence of the disease.

Recurrent hemorrhage of ligamentum flavum cyst: case report

A 39-year-old man presented with recurrent lower back and leg pain for 8 months due to repeated hemorrhage into an L5 ligamentum flavum cyst. Lumbar MR imaging showed an extradural cystic mass originating from the ligamentum flavum on the right side in the L5 segment. Microsurgical laminotomy and flavectomy were performed. The symptoms resolved completely and the patient had an uneventful postoperative recovery.