Ossification Of The Yellow Ligament Research Articles

Ossification of the yellow ligament in the cervical spine – an unusual location

Ossification of the yellow ligament in the cervical spine – an unusual location

CERVICAL DEGENERATIVE MYELOPATHY, PANORAMIC REVIEW

Introduction: cervical degenerative myelopathy (DCM) is a general term that entails multiple etiologies. DCM is a group of pathological entities that originate compression of the cervical spinal cord, where spasticity, hyperreflexia, pathological reflexes, loss of manual dexterity, among others, are found. Objective: to detail the current information related to cervical degenerative myelopathy, epidemiology, clinical presentation, role of complementary examinations, pathophysiology, pathogenesis and treatment. Methodology: a total of 32 articles were analyzed in this review, including review and original articles, as well as clinical cases, of which 21 bibliographies were used because the other articles were not relevant to this study. The sources of information were PubMed, Google Scholar and Cochrane; the terms used to search for information in Spanish, Portuguese and English were: cervical degenerative myelopathy, cervical spondylotic myelopathy, cervical pain, ossification of the yellow ligament and degenerative disc disease. Results: cervical myelopathy occurs in almost all individuals with canal stenosis greater than 60%. Spinal cord injury (SCI) is a devastating disorder that influences remarkable neurological morbidity and significant wear and tear on quality of life. The incidence and prevalence of SCI in North America is between 4.1 and 60.5 per 100,000, robust epidemiological data is difficult to obtain because of the multifactorial etiology of the disease process. Conclusions: cervical degenerative myelopathy involves multiple etiologies, all these entities together represent the most common reason for degenerative and non-traumatic alteration of the spinal cord in adult individuals. Degenerative disorders are more common at C5 and C6 or C6 and C7, because of the increased mobility in these sections. It is difficult to obtain solid epidemiological data because of the multifactorial etiology of the disease process. The symptoms and signs presented by the pathology are varied, so an adequate physical examination and a good clinical history should be taken. The pathology can significantly alter neurological function and lead to disability, so early recognition and treatment can prevent further deterioration of affected individuals. Surgical decompression is almost universally indicated with the intention of preventing progression and achieving maximum recovery potential. KEY WORDS: myelopathy, cervical, degenerative, pain, spinal, neuralgia.

Ossification of the Ligamentum Flavum of the Cervical Spine in an Iranian Woman: Report of a Case With Myelopathy and Review of the Literature

Background and Importance: Ossification of the ligamentum flavum (OLF) is a pathological condition that affects the yellow ligaments, mostly in adult males between the ages of 45 to 70. Ossification is more common in the thoracolumbar region with an accompanying progressive neurological deficit, and its occurrence within the cervical spine is quite rare. Ossification of the yellow ligament is so common in East Asian countries that it is regarded as a frequently occurring aging pathology in the people of this region. Its existence in other ethnic groups is significantly lower. Case Presentation: A 68-year-old Iranian woman with progressive quadriparesis is presented. Cervical computerized tomography and MRI scans revealed two-level, bilateral, posteriorly located, ossified masses occurring at the C4-C5 and C5-C6 levels, which coincided with the ossification of the yellow ligament. Cervical laminectomy and excision of both masses were undertaken and the patient gradually recovered from his resultant neurological symptoms. Conclusion: Symptomatic cervical OLF is a markedly rare pathological finding and is typically illustrated as a medical case report. In a careful review of the literature including the presented patient, we could uncover only 77 cases involving a documented symptomatic cervical OLF.

Symptomatic thoracic ossified ligamentum flavum in achondroplasia: A case report and literature review

Background: In a patient with achondroplasia, it is rare to encounter thoracic cord compression due to both spinal stenosis and ossification of the yellow ligament (OYL).Case Description: A 33-year-old achondroplastic female presented with a progressive spastic paraparesis attributed to thoracic stenosis combined with T10-T11 OYL. Following a laminectomy, the patient demonstrated a marked recovery of neurological function.Conclusion: This case and 12 others from the literature demonstrated that achondroplastic patients who present with myelopathy secondary to thoracic stenosis and OYL can be readily diagnosed with MR/CT and successfully treated utilizing decompressive laminectomies with/without fusions (i.e., for those crossing the thoracolumbar junction).

Surgical outcomes for late neurological deficits after long segment instrumentation for degenerative adult spinal deformity.

The most catastrophic symptom of proximal junctional failure (PJF) following long instrumented fusion surgery for adult spinal deformity (ASD) is neurological deficits. Although previous reports have shown that PJF usually developed during the early postoperative period, some patients showed late neurological deficits. The aim of this study was to report the incidence, characteristics, and surgical outcomes of PJF with late neurological deficits. Patients surgically treated for ASD at a single institution were retrospectively reviewed. Among them, the patients requiring revision surgery for newly developed neurological deficits at least 6 months after the initial surgery were included. Patient demographic, radiographic, surgical, and clinical data were investigated. Neurological status was assessed using the Frankel grading system. PJF with late neurological deficits developed in 18 of 385 patients (4.7%). The mean age at the onset of neurological deficits was 72.0 ± 6.0 years, and the median time from the initial surgery was 4.5 years. The most common pathology of PJF was adjacent disc degeneration and subsequent canal stenosis (11 patients). Five patients showed disc degeneration with aseptic bone destruction. Fractures at the upper instrumented vertebra (UIV), UIV + 1, and UIV + 2 occurred in 2, 3, and 2 patients, respectively. Ossification of the yellow ligament, which had not been found at the first surgery, was identified in 6 patients. Eight patients showed improvement of their neurological deficits and 10 patients showed no improvement by the final follow-up. Perioperative major complications occurred in 8 of 18 patients. The incidence of PJF with late neurological deficits following ASD surgery was 4.7% in this cohort. The patients showed several morphological features. After revision surgery, perioperative complications were common and the prognosis for improved neurological status was not favorable.

Management of Thoracic Myelopathy Caused by Ossification of the Posterior Longitudinal Ligament Combined with Ossification of the Yellow Ligament at the Same Level―4 Cases Report and Review of Literature―

Management of Thoracic Myelopathy Caused by Ossification of the Posterior Longitudinal Ligament Combined with Ossification of the Yellow Ligament at the Same Level―4 Cases Report and Review of Literature―

Ossification of the yellow ligament in the cervical spine - an unusual location.

Ossification of the yellow ligament (OYL) or ligamentum flavum, usually occurs in the thoracic spine. Focal OYL occurring in the cervical spine is considered rare and is sparsely reported in the literature. We came across a 30-year-old male patient with progressive left upper limb and bilateral lower limb weakness over a period of 3 months, associated with an unsteady gait. Clinical examination revealed bilateral generalized hyper-reflexia in both upper and lower limbs, inverted supinator jerk, Hoffman’s sign and clonus. Myelopathy due to cord compression was suspected and further investigations were done. MRI and CT scans revealed a bony mass in relation to the C6 spinous process projecting anterosuperiorly and narrowing the cervical spinal canal causing cord signal changes from C4 to C6 levels. In view of the deteriorating neurological status, immediate surgery in the form of decompression and posterior stabilization from C4-C6 was performed. Patient gradually recovered after surgery and attained full functional status. We report this case considering the unusual location of OYL and its successful management.

Ossification of the yellow ligament in thoracic spine: a case report

Ossifications of the yellow ligament (OYL) and calcification of yellow ligament are relatively rare clinical entities, and can make sever morbidity surgical evaluation can relived the sign and symptom and improve life quality we present a patient with ossification of the yellow ligament in level of T9 and T10 of thoracic spin.

Cervical ribs as a caution for spine surgeons in thoracic spinal surgery

Cervical ribs are well-described anomalous additional ribs arising from the seventh cervical vertebrae, but they can be a potential cause for wrong-level surgery. We report a case of a 71-year-old female with bilateral lower limb weakness and numbness due to spinal stenosis from T8 to T11 correlated on magnetic resonance imaging (MRI). However, computed tomography (CT) of thoracic spine showed ossification of the yellow ligament (OYL) one level distal at T9-T12. The whole spine CT revealed the presence of cervical ribs, and the initial discrepancy was caused by counting thoracic spinal levels according to the rib heads. Intraoperative decompression confirmed the dura had merged with OYL at T8–T11. The patient made a partial neurological recovery and could walk independently at 6-month follow-up. This case serves as a reminder for spine surgeons surgical implications of cervical ribs when operating on the thoracic spine, and the authors suggest additional radiological examinations to include the cervical spine to minimize the chances of wrong-level surgery.

Nursing review of cervical laminectomy and fusion.

Background:Cervical radiiculopathy/nerve root compression, myelopathy/cord compression are variously attributed to stenosis/narrowing of the spinal canal [anterior/posterior (AP) to less than 10 mm is defined as absolute stenosis, and 13 mm as relative stenosis]. Additional pathology includes disc herniations, ossification of the posterior longitudinal ligament (OPLL), and ossification of the yellow ligament (OYL). Patients, typically over 60 years of age, may present with severe myeloradicular syndromes requiring multilevel laminectomies and posterior instrumented fusions.Methods:Patients typically first undergo magnetic resonance imaging (MRI) studies of the cervical spine that best demonstrate soft tissue pathology; spinal cord and/or nerve root compression in three dimensions (AP/coronal (front/back), lateral (side), and axial (cross section)). Computed tomography (CT) studies better define ossification/calcific changes contributing to stenosis, including OPLL and/or OYL.Results:If there is multilevel cervical pathology and an adequately preserved cervical lordosis (curvature with the neck), a cervical laminectomy may provide adequate cord/root decompression. Performed under intraoperative monitoring, the laminae (bones cover the back of the cervical spine), spinous processes (midline bony protuberant structures), and OYL may be directly removed. Posterior fusions, utilizing varying instrumentation/constructs may prevent reversal of the lordosis (kyphosis: curve angled forward) and re-tethering of the spinal cord.Conclusions:Patients with myeloradiculopathy (cord/root compression) and multilevel cervical stenosis attributed to disc herniations, OPLL, and/or OYL with an adequate lordosis may require multilevel laminectomy and an instrumented fusion.

High posterior cervical fusion rates with iliac autograft and Nanoss/bone marrow aspirate.

Background:Patients with severe cervical multilevel stenosis and an adequate lordotic curvature often undergo multilevel laminectomies with posterior instrumented fusions. Although the “gold standard” for the fusion mass remains iliac crest autograft, many require additional volume provided by bone graft expanders. Here, we studied the fusion rates for 32 patients undergoing multilevel cervical laminectomy and vertex/rod/eyelet/titanium cable fusions utilizing lamina/iliac autograft and the bone graft expander Nanoss (RTI Surgical, Alachua, FL, USA) with autogenous bone marrow aspirate (BMA).Methods:Thirty-two patients, averaging 63.0 years of age, presented with severe cervical myeloradiculopathy (average Nurick Grade 4.4). Magnetic resonance (MR) studies documented 2–3-level high intrinsic cord signals, whereas computed tomography (CT) scans confirmed marked stenosis and ossification of the posterior longitudinal ligament (OPLL)/ossification of the yellow ligament (OYL). Patients underwent multilevel lamnectomies/instrumented fusions, and were followed up for an average of 2.7 years.Results:Multilevel laminectomies (2.8 levels) and average 7.8-level vertex/rod/eyelet/cable fusions were performed utilizing lamina/iliac crest autograft and Nanoss/BMA. Fusion was confirmed on X-ray/CT studies an average of 4.7 months postoperatively in 31 of 32 patients (97%); there was just one pseudarthrosis requiring secondary surgery. The only other complication was a delayed transient C5 palsy that fully resolved in 6 postoperative months.Conclusions:Thirty-two severely myelopathic underwent 2.8-level cervical laminectomies/7.8 level fusions utilizing lamina/iliac autograft and Nanoss/BMA. Fusion was documented on both dynamic X-ray and CT studies in 31 of 32 (97%) patients an average of 4.7 months postoperatively. Nanoss/BMA appears to be a safe and effective bone graft expander that can be utilized for posterior cervical fusions.

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.

Nursing review of diagnosis and treatment of lumbar degenerative spondylolisthesis.

Background:In the lumbar spine, degenerative spondylolisthesis or degenerative (not traumatic) slippage of one vertebral body over another is divided into 4 grades – grade I (25%), grade II (50%), grade III (75%), and grade IV (100%). Dynamic X-rays, magnetic resonance (MR), and computed tomography (CT) scans document the slip secondary to arthritic changes of the facet joint plus stenosis, ossification of the yellow ligament, disc herniations, and synovial cysts. MR best demonstrates soft tissue pathology whereas CT better delineates ossific/calcified disease.Methods:Grade I degenerative spondylolisthesis, typically found at the L4–L5 level followed by L3–L4 and L5S1, is more common in females (ratio 2:1) over the age of 65. Symptoms include radiculopathy (root pain) and neurogenic claudication (e.g., pain with ambulation, requiring the patient to stop, rest, sit down). Symptoms/signs may include unilateral/bilateral radiculopathy and uni/multifocal motor, reflex, and sensory deficits in. Some may also present with a cauda equina syndrome (e.g., paraparesis/sphincter dysfunction).Results:Surgery for grade I-II spondylolisthesis may include laminectomy alone, laminectomy/noninstrumented fusion or with an instrumented fusion. Older patients with osteoporosis are more likely to have no fusion or a noninstrumented fusion. All fusions utilize autograft harvested from the laminectomy that may or may not be combined with a bone graft expander (to increase the fusion mass) combined with autogenous bone marrow aspirate. The fusion mass is placed over the transverse processes following decortication.Conclusions:Patients with multilevel spinal stenosis and degenerative spondylolisthesis may require decompressive lumbar laminectomies alone or in combination with noninstrumented or instrumented fusions.

Ossification Of The Ligamentum Flavum Of The Lumbar Spine In Caucasians: Case Series

Ossification of the ligamentum flavum or OLF is a disease with heterotopic ossification in this spinal ligament. The key of OLF pathogenesis is the differentiation of fibroblasts into osteoblasts. The majority of cases of ossification of the yellow ligament occur at the lower third of the thoracic or the thoracolumbar spine. However, the literature contains only few reports of patients with OLF of the lumbar spine. The clinical presentation of lumbar OLF is radiculopathy or intermittent neurogenic claudication, although some might remain asymptomatic. Herein, we present 8 Caucasians with symptomatic lumbar OLf. The age and gender as well as the clinical picture, characteristic radiological features, the number of the affected levels will be described. The tips and tricks for achievement of a successful decompressive laminectomy, as the treatment of choice, done at one level in three and at two levels in five cases will be described. Furthermore, the degree of adherence of the lesions to dura and ultimate outcome will be discussed.

Incidental durotomy in spine surgery: first aid in ten steps.

Incidental durotomy (ID) is the most common complication of spine surgery. Revision procedures, ossification of the yellow ligament, or synovial cysts are well-known risk factors. The size, shape, and severity of ID are unpredictable, ranging from a pinpoint hole to a several centimeters large dural laceration with transected fibers following the slippage of a cutting burr. Furthermore, the occurrence of ID is always unexpected. Intra-operative management is often based on a steep learning curve rather than a structured scheme. To provide an intra-operative ten-step closure technique (10ST) for IDs of varying severity. A database of 4020 consecutive surgeries for lumbar degenerative disease over the past 4 years was searched for ID. The records of 176 patients were analyzed. Two dural repair techniques were compared: the "individual" technique (InT) and the 10ST. The overall prevalence of ID was 4.4%. The prevalence was lowest in virgin micro-discectomies (1.7%) and ranged from 3.6% in decompression for spinal canal stenosis up to 14.5% in revision procedures. All surgeries were performed with the aid of a microscope. Among 107 primary surgeries, the InT achieved a single-stage closure of the ID in 96 procedures (89.7%). Among 20 virgin surgeries, the 10ST was successful in all cases (P = 0.21). Among 42 re-do procedures following failed attempts to stop cerebrospinal fluid (CSF) leakage, the InT achieved single-stage closure in 36 procedures (85.7%). The 10ST was successful in all 26 cases (P = 0.03). The follow-up was 1 year. The 10ST should be considered for successful single-stage closure in primary repair of ID.

Incidence and management of cerebrospinal fluid fistulas in 336 multilevel laminectomies with noninstrumented fusions.

Background:The incidence (e.g., 3–27%) and the types of cerebrospinal fluid (CSF) fistulas occurring during multilevel lumbar laminectomy with noninstrumented spinal fusions varies.Methods:From 2000 to 2015, we retrospectively evaluated the incidence/etiologies of CSF fistulas occurring for 336 patients undergoing average 4.7 laminectomies with average 1.4 level noninstrumented fusions over a 15 year period. The varied etiologies of CSF leaks included; ossification of the yellow ligament (OYL) extending through the dura, postoperative surgical scar, iatrogenic traumatic leak, epidural steroid injections (ESI), resection of synovial cysts, and the removal of intradural tumors. Techniques for primary repairs included combinations of; 7-0 Gore-Tex (Newark, Delaware, USA) sutures, micro-dural staples, muscle patch/other (e.g., bovine pericardial) grafts, fibrin sealants/glues (e.g., Tisseel; Baxter International Inc., Westlake Village, CA, USA), and Duragen (Integra LifeSciences, Hawthorne, NY, USA) including both the thin and suturable types.Results:The etiologies of CSF fistulas in descending order included: Epidural spinal injections (ESI) (7 patients), synovial cysts (6 patients), OYL (5 patients), and equally for postoperative scar and intradural tumors (3 patients). CSF fistulas occurred in 24 (7.14%) of 336 patients; this frequency was reduced to 4.2% when ESI and intradural tumors were excluded.Conclusion:CSF fistulas occurred in 7.14% of 336 patients undergoing average 4.7 multilevel laminectomies with average 1.4 level noninstrumented fusions attributed to a lumbar stenosis with mild/moderate instability. The dural repair addressed seven prior ESI, six synovial cysts, five OYL, and operative scarring and intradural tumors (three apiece). Knowing the pathologies contributing to CSF fistulas should help the surgeon to better anticipate and treat these fistulas.

Medicolegal Corner: When minimally invasive thoracic surgery leads to paraplegia.

A patient with mild cervical myelopathy due to multilevel ossification of the posterior longitudinal ligament (OPLL) initially underwent a cervical C3-T1 laminectomy with C2-T2 fusion utilizing lateral mass screws. The patient's new postoperative right upper extremity paresis largely resolved within several postoperative months. However, approximately 6 months later, the patient developed increased paraparesis attributed to thoracic OPLL and Ossification of the yellow ligament (OYL) at the T2-T5 and T10-T11 levels. The patient underwent simultaneous minimally invasive (MIS) unilateral MetRx approaches to both regions. Postoperatively, the patient was paraplegic and never recovered function. Multiple mistakes led to permanent paraplegia due to MIS MetRx decompressions for T2-T5 and T10-11 OPLL/OYL in this patient. First, both thoracic procedures should have been performed “open” utilizing a full laminectomy rather than MIS; adequate visualization would have likely averted inadvertent cord injury, and the resultant CSF leak. Second, the surgeon should have used an operating microscope. Third, the operation should have been monitored with somatosensory evoked potentials (SEP), motor evoked potentials (MEP), and EMG (electromyography). Fourth, preoperatively the patient should have received a 1-gram dose of Solumedrol for cord “protection”. Fifth, applying Gelfoam as part of the CSF leak repair is contraindicated (e.g. due to swelling in confined spaces- see insert). Sixth, if the patient had not stopped Excedrin prior to the surgery, the surgery should have been delayed to avoid the increased perioperative risk of bleeding/hematoma.

Prevalence, Distribution, and Morphology of Thoracic Ossification of the Yellow Ligament in Japanese

A cross-sectional study. To gain an insight for the prevalence, morphology, and distribution of thoracic ossification of the yellow ligament (OYL) by computed tomography (CT) and review of the literature. The epidemiology and etiology of OYL remains obscure. To date, to the best of our knowledge, there is no study that comprehensively evaluated thoracic spine by CT to assess the prevalence, distribution, and morphology of OYL in a large enough sample size with wide age distribution. The participants of this study were the patients who have undergone chest CT for the examination of pulmonary diseases in our institute. The patients with previous thoracic spine surgery and younger than 15 years were excluded. Prevalence, distribution, and morphology of thoracic OYL were reviewed. A total of 3013 patients (1261 females and 1752 males) with the mean age of 65 years were recruited. The CT-based evidence of OYL was noted in 1094 (428 females and 666 males) individuals (36%). Single-level involvement was noted in 532 cases, whereas 562 individuals presented multilevel involvement.Statistical analyses revealed that OYL was noted at a significantly higher rate among the males (P = 0.022). Of a total of 2051 OYLs, 779 central type OYLs, a mushroom-shaped ossification localized at the center of laminae, and 1272 noncentral type OYLs were noted. Distribution of the thoracic OYL formed 2 peaks with the highest and second highest peak found at T10-T11 and T4-T5, respectively. Interestingly, OYL is noted at consistent rates after the age of 30; however, its size increased in age-dependent manners. The prevalence of thoracic OYL in Japanese was 36%. A further study disclosing the association between clinical manifestations and size and/or morphology of OYL is warranted.

A review article on the diagnosis and treatment of cerebrospinal fluid fistulas and dural tears occurring during spinal surgery

Background:In spinal surgery, cerebrospinal fluid (CSF) fistulas attributed to deliberate dural opening (e.g., for tumors, shunts, marsupialization of cysts) or inadvertent/traumatic dural tears (DTs) need to be readily recognized, and appropriately treated.Methods:During spinal surgery, the dura may be deliberately opened to resect intradural lesions/tumors, to perform shunts, or to open/marsupialize cysts. DTs, however, may inadvertently occur during primary, but are seen more frequently during revision spinal surgery often attributed to epidural scarring. Other etiologies of CSF fistulas/DTs include; epidural steroid injections, and resection of ossification of the posterior longitudinal ligament (OPLL) or ossification of the yellow ligament (OYL). Whatever the etiology of CSF fistulas or DTs, they must be diagnosed utilizing radioisotope cisternography (RIC), magnetic resonance imaging (MRI), computed axial tomography (CT) studies, and expeditiously repaired.Results:DTs should be repaired utilizing interrupted 7-0 Gore-Tex (W.L. Gore and Associates Inc., Elkton, MD, USA) sutures, as the suture itself is larger than the needle; the larger suture occludes the dural puncture site. Closure may also include muscle patch grafts, dural patches/substitutes (bovine pericardium), microfibrillar collagen (Duragen: Integra Life Sciences Holdings Corporation, Plainsboro, NJ), and fibrin glues or dural sealants (Tisseel: Baxter Healthcare Corporation, Deerfield, IL, USA). Only rarely are lumbar drains and wound-peritoneal and/or lumboperitoneal shunts warranted.Conclusion:DTs or CSF fistulas attributed to primary/secondary spinal surgery, trauma, epidural injections, OPLL, OYL, and other factors, require timely diagnosis (MRI/CT/Cisternography), and appropriate reconstruction.

Thoracic myelopathy caused by ossification of the yellow ligament in patients with posterior instrumented lumbar fusion

The objective of this study was to investigate thoracic myelopathy caused by ossification of the yellow ligament (OYL) in patients with posterior instrumented lumbar fusion. Seven patients, who had undergone posterior instrumented lumbar fusion, presented with thoracic myelopathy caused by OYL. No patient had a history of thoracic myelopathy at previous surgery. Instrumented fusions were performed from L1-5 in two patients, L2-5 in three patients and L1-S1 and L2-S1 in one patient each, respectively. MRI and CT scans were performed to confirm cord compression by OYL. Of the seven patients, six patients underwent decompressive laminectomy and OYL removal while one was treated conservatively. The average time to presentation after first surgery was 63.4 months. OYL was located at T9-10 in two patients, T11-12 in three patients, and T10-11 and T9-11 in one patient each, respectively. All patients had a myelopathic gait and the average Japanese Orthopaedic Association (JOA) score was 3.9, preoperatively. The average JOA score improved from 3.7 to 8 and the average recovery rate was 58.9 % in the six patients who underwent surgical intervention. However, the JOA score fell from 5 to 4 in the one patient who was treated conservatively. We report seven patients who suffered from thoracic myelopathy after instrumented lumbar fusion. Surgeons must be aware of the possibility of thoracic myelopathy caused by OYL at the thoracolumbar junction, especially in patients with a complaint of gait disturbance after long instrumented lumbar fusion.