Severe Ossification Of The Posterior Longitudinal Ligament Research Articles

Correlation between paraspinal muscle fat infiltration and thoracic vertebral degeneration based on phantom-less QCT: a novel insight into thoracic vertebral degeneration.

This study aimed to elucidate the correlation between the degree of fat infiltration (FI) in thoracic paraspinal muscles and thoracic vertebral degeneration (TVD). This cross-sectional study comprised 474 patients who underwent standard thoracic computed tomography (CT) scans. The FI was quantified as the percentage of adipose tissues within the cross-sectional area of thoracic paraspinal muscles. Thoracic vertebra was assessed in terms of osteoporosis, ossification of the anterior longitudinal ligament (OALL), ossification of the posterior longitudinal ligament (OPLL), intervertebral disc calcification, intervertebral disc cavity, and facet joint osteoarthritis (FJO). Logistic regression, linear regression, subgroup, and receiver operating characteristic (ROC) analyses were assessed to evaluate the association between FI and TVD. Multivariate logistic regression revealed that more severe FI was closely associated with more serious osteoporosis (P < 0.001). Furthermore, after adjusting for only age, higher FI was significantly associated with nastier FJO (P < 0.05). In male patients, severe FI was greatly associated with worse osteoporosis (P < 0.05). In female patients, severe FI maintained close correlations with more severe osteoporosis and FJO (P < 0.05). Furthermore, in patients aged < 60 or ≥ 60 years, higher FI had a strong correlation with more severe osteoporosis (P < 0.001). In patients aged < 60 years, higher FI was associated with worse intervertebral disc calcification, OALL, and FJO (P < 0.05). Meanwhile, in patients aged ≥ 60 years, increased FI was only associated with severe OPLL (P < 0.05). Multivariate linear regression showed that FI negatively correlated with bone mineral density in the general population and different sex and age groups (P < 0.001). ROC analysis indicated that FI could predict the occurrence of TVD (P < 0.05). Higher FI is associated with more severe TVD. Studies on TVD are currently limited; therefore, this study enriches the related research on TVD, and our findings would facilitate the early prediction and diagnosis of TVD in clinical practice. Furthermore, our findings indicate that thoracic spine pain (TSP) caused by TVD can be prevented, potentially improving the prognosis of patients with TSP.

Application of the "Klotski Technique" in Cervical Ossification of the Posterior Longitudinal Ligament With En Bloc Type Dura Ossification.

The anterior controllable antedisplacement and fusion (ACAF) technique is a new procedure for the treatment of cervical ossification of the posterior longitudinal ligament (OPLL) that requires management of the disc adjacent to the ossification. This study describes a novel technique to reduce the number of fixed segments, namely, the "Klotski technique." The efficacy of ACAF using the Klotski technique was compared with that of anterior cervical corpectomy and fusion (ACCF) in the treatment of OPLL with en bloc type dural ossification (DO). The clinical data of 25 patients with severe OPLL and en bloc type DO who were treated by the ACAF Klotski technique or ACCF at our hospital from January 2020 to January 2022 were retrospectively analyzed. In the Klotski technique, the number of segments fused within the OPLL is limited. The antedisplacement space was designed according to the shape of the vertebrae-OPLL-DO complex (VODC). Then, the entire VODC was antedisplaced as in Klotski. Neurological function and image examination were assessed preoperatively and postoperatively. Complications associated with surgery were recorded. Patients were followed up for 24-36 months. There were 11 patients who were treated with ACAF and 14 patients who were treated with ACCF. At 2 weeks after surgery, the incidence of neurological deterioration was 21.4% (3 of 14) in the ACCF group and 9.1% (1 of 11) in the ACAF group. The incidence of intraoperative cerebrospinal fluid leakage (CFL) was 35.7% (5 of 14) in the ACCF group and 9.1% (1 of 11) in the ACAF group. The postoperative follow-up JOA scores of the patients in both groups were significantly better than their preoperative JOA scores (p<0.05). The Klotski technique for ACAF is a good option for the treatment of patients with en bloc type OPLL-DO, as it limits the number of fused segments, has a low incidence of CFL and neurologic deficits and is associated with good neurological recovery.

Effects of cervical rotatory manipulation on the cervical spinal cord complex with ossification of the posterior longitudinal ligament in the vertebral canal: A finite element study.

Background: There are few studies focusing on biomechanism of spinal cord injury according to the ossification of the posterior longitudinal ligament (OPLL) during cervical rotatory manipulation (CRM). This study aimed to explore the biomechanical effects of CRM on the spinal cord, dura matter and nerve roots with OPLL in the cervical vertebral canal. Methods: Three validated FE models of the craniocervical spine and spinal cord complex were constructed by adding mild, moderate, and severe OPLL to the healthy FE model, respectively. We simulated the static compression of the spinal cord by OPLL and the dynamic compression during CRM in the flexion position. The stress distribution of the spinal cord complex was investigated. Results: The cervical spinal cord experienced higher von Mises stress under static compression by the severe OPLL. A higher von Mises stress was observed on the spinal cord in the moderate and severe OPLL models during CRM. The dura matter and nerve roots had a higher von Mises stress in all three models during CRM. Conclusion: The results show a high risk in performing CRM in the flexion position on patients with OPLL, in that different occupying ratios in the vertebral canal due to OPLL could significantly increase the stress on the spinal cord complex.

Posterolateral Floating Technique for the Thoracic Ossification of the Posterior Longitudinal Ligament with Navigation: A Technical Note.

We describe a floating technique via a posterolateral approach with intraoperative O-arm navigation to facilitate decompression of the spinal cord in thoracic myelopathy due to severe ossification of the posterior longitudinal ligament (OPLL). A 62-year-old man with myelopathy due to thoracic OPLL had left-leg muscle weakness, urinary disturbance, and spastic gait. Bilateral leg pain and gait disturbance had persisted for 2 years. He was successfully treated by the posterolateral OPLL floating procedure and posterior pedicle fixation under O-arm navigation. At a 2-year follow-up, manual muscle testing results and sensory function of the left leg had recovered fully. His cervical Japanese Orthopedic Association score had improved from 5/12 to 11/12. The novel intraoperative O-arm navigation-guided posterolateral floating procedure for thoracic OPLL is effective for achieving precise decompression and strong fixation with a posterior approach only and can provide an excellent result for severe thoracic OPLL without the risk of adverse events from intraoperative radiation.

Anterior Cervical Controllable Antedisplacement and Fusion (ACAF): Improving Outcomes for Severe Cervical Ossification of the Posterior Longitudinal Ligament.

The detailed steps to perform ACAF have been described previously1. Briefly, following induction of general endotracheal anesthesia, a standard right- or left-sided Smith-Robinson incision is made. Discectomies are performed at the involved levels. By measuring the thickness of the OPLL on an axial preoperative computed tomography scan at each compressed level, the amount of each anterior vertebral body to be resected can be calculated preoperatively. This was, in general, equal to the thickness of the ossified mass at the same level. The previously calculated portion of each involved body in the vertebral body-OPLL complex is resected. Following the creation of a contralateral longitudinal osseous trough, the prebent anterior cervical plate is then placed, and the screws are installed after proper drilling and taping on the remaining vertebral bodies. The screws utilized in this procedure should not be too short to achieve adequate purchase in the vertebral body. Subsequently, the intervertebral cages are inserted. Thus, the vertebral body-OPLL complex is temporarily stabilized for the next procedure. Next, an ipsilateral longitudinal osseous trough is created to completely isolate the vertebral body-OPLL complex. Notably, the objective of complete isolation of the vertebral body-OPLL complex is to further anteriorly hoist the complex to decompress the spinal cord. Finally, screws are inserted through the plate and into each vertebral body and are gradually tightened to displace the bodies anteriorly. Allogenic iliac bone graft is placed in the longitudinal bone troughs to promote fusion. Nonoperative treatment is frequently ineffective. Traditional surgical interventions have included anterior cervical corpectomy and fusion (ACCF), posterior laminoplasty, and laminectomy2,3. ACCF focuses on resecting the ventral ossified mass in order to obtain direct decompression; however, this technique is very technically demanding, with a high risk of complications. In addition, the clinical benefits of ACCF will be limited when the OPLL extends over >3 levels. Posterior decompression can achieve indirect decompression by allowing the spinal cord to float away from the ossified mass. This technique depends largely on the preoperative presence of cervical lordosis and is contraindicated in patients with kyphosis or severe OPLL. In addition, posterior decompression surgery has been associated with a high incidence of late neurological deterioration and even revision surgery2. ACAF combines the advantages of direct decompression as occurs with ACCF with the limited manipulation of the canal contents as occurs with the posterior approach4-6. The procedure considers the ossified mass and the vertebral body as a single unit. Decompression is accomplished by moving the vertebral body with the OPLL ventrally away from the spinal cord. The preserved part of the vertebral body-OPLL complex becomes part of the anterior wall of the spinal canal. Without direct instrument manipulation inside the canal, the occurrence of cerebrospinal fluid leakage, hemorrhage, and intraoperative neural injury can be minimized5. Compared with a posterior approach, ACAF can achieve more decompression of the cord, especially in patients with cervical kyphosis and those with >60% of the spinal canal occluded6. This procedure can yield satisfactory clinical outcomes with fewer surgery-related complications1,4-6,9. A single-center, prospective, randomized controlled study showed significantly better Japanese Orthopaedic Association scores and recovery rates at 1 year for ACAF compared with laminoplasty for the treatment of multilevel OPLL in cases in which the occupying ratio of the canal was >60% occluded or the K-line (i.e., a virtual line between the midpoints of the anteroposterior canal diameter at C2 and C7) was negative9. In addition, patients who underwent ACAF had better preservation of cervical lordosis and sagittal balance9. The cervical segments to be treated should include all of the segments with OPLL that are causing spinal cord compression.The uncinate process can be utilized as a safe anatomical landmark for the longitudinal osteotomies in order to avoid vertebral artery injury, even in cases with severely ossified masses.Careful evaluation of the vertebral artery on preoperative magnetic resonance imaging or computed tomography is of great importance.Appropriately increasing the curvature of the cervical plate can further enlarge the space for the following antedisplacement of the vertebral body-OPLL complex.The location of the uncinate processes must be confirmed before the creation of the 2 longitudinal osseous troughs7,8.The preserved superior and inferior vertebral end plates should be made as smooth and mutually parallel as possible.The thickness of the anterior part of the vertebral bodies to be resected should be calculated preoperatively.The posterior longitudinal ligament behind the involved segments should not be resected. ACAF = anterior cervical controllable antedisplacement and fusionACCF = anterior cervical corpectomy and fusionOPLL = ossification of the posterior longitudinal ligamentCT = computed tomographyJOA = Japanese Orthopaedic AssociationMRI = magnetic resonance imagingOR = occupying rate of the spinal canalVOC = vertebral bodies-OPLL complexRR = recovery rateCSF = cerebrospinal fluidUP = uncinate processTF = transverse foramen.

Unveiling the genetic variation of severe continuous/mixed-type ossification of the posterior longitudinal ligament by whole-exome sequencing and bioinformatic analysis

Ossification of the posterior longitudinal ligament (OPLL) in the cervical spine is known as a rare, complex genetic disease, its complexity being partly because OPLL is diagnosed by radiological findings regardless of clinical or genetic evaluations. Although many genes associated with susceptibility have been reported, the exact causative genes are still unknown. We performed an analysis using next-generation sequencing and including only patients with a clear involved phenotype. This was a case control study. A total of 74 patients with severe OPLL and 26 healthy controls were included. Causal single-nucleotide variant (SNV), gene-wise variant burden (GVB), and related pathway METHOD: We consecutively included the severe OPLL patients with continuous-/mixed-type and an occupying ratio of ≥ 40%, and performed whole-exome sequencing (WES) and bioinformatic analysis. Then, a validation test was performed for candidate variations. Participants were divided into 4 groups (rapidly-growing OPLL, growing rate ≥ 2.5%/y; slow-growing, < 2.5%/y; uncertain; and control). WES was performed on samples from 74 patients with OPLL (rapidly-growing, 33 patients; slow-growing, 37; and uncertain, 4) with 26 healthy controls. Analysis of 100 participants identified a newly implicated SNV and 4candidate genes based on GVB. The GVB of CYP4B1 showed a more deleterious score in the OPLL than the control group. Comparison between the rapidly growing OPLL and control groups revealed seven newly identified SNVs. We found significant association for 2 rare missense variants; rs121502220 (odds ratio [OR]=infinite; minor allele frequency [MAF]=0.034) in NLRP1 and rs13980628 (OR= infinite; MAF=0.032) in SSH2. The 3 genes are associated with inflammation control and arthritis, and SSH2 and NLRP1 are also related to vitamin D modulation. Identification of unique variants in novel genes such as CYP4B1 gene may induce the development of OPLL. In subgroup analysis, NLRP1 and SSH2 genes coding inflammation molecules may related with rapidly-growing OPLL.

Prospective Investigation of Postoperative Complications in Anterior Decompression with Fusion for Severe Cervical Ossification of the Posterior Longitudinal Ligament: A Multi-institutional Study.

A prospective multicenter study. This study aims to investigate the postoperative complications of anterior decompression with fusion (ADF) for the treatment of cervical ossification of the posterior longitudinal ligament (OPLL). Surgical treatment for cervical OPLL has a high risk of various complications. ADF is reported to be effective for cervical OPLL, especially for massive OPLL. However, few studies have focused on the surgical complications of ADF. We prospectively included 102 patients undergoing ADF for severe cervical OPLL with average canal occupying ratio of 49.8%. We evaluated systemic and local complications, neurological complications, and risk factors related to the postoperative complications. Frequently observed complications included graft/ implant complications (18.6%), neurological complications (11.8%), and cerebrospinal fluid leak (11.8%). Motor palsy involving only the upper extremity was found in nine patients (8.8%), and other motor palsies involving the lower extremities were found in three patients (2.9%). None of the preoperative factors were significantly associated with the occurrence of neurological palsies, whereas the number of operated levels was a significant factor related to the postoperative graft/implant complications (P = 0.003; odds ratio, 2.112). The incidence of graft/implant complications and related reoperation increased as the number of operated levels increased (especially four levels or more). Most motor palsies were observed immediately after surgery. Of the motor palsies in the bilateral upper extremities and palsies involving the lower extremities, 85.7% showed good recovery, whereas only 40% of unilateral upper extremity motor palsies showed good recovery during the follow-up period. In ADF for cervical OPLL, the number of operated levels was a significant factor related to the postoperative complication. Specifically, the incidence of graft/implant complications and reoperation rate increased in ADF with four or more levels.Level of Evidence: 3.

Modified axial computed tomography classification of cervical ossification of the posterior longitudinal ligament: selecting the optimal operating procedure and enhancing the accuracy of prognosis.

Cervical ossification of the posterior longitudinal ligament (OPLL) causes spinal cord compression, which can lead to myelopathy or radiculopathy. Non-surgical treatments have little effect on this condition. Current OPLL classification systems offer little guidance on the selection of an appropriate operating procedure. In this study, we developed a modified axial computed tomography classification (MACTC) scheme. We then examined the usefulness of the MACTC scheme and two other existing classification schemes in guiding OPLL operation choice. Following screening in which a defined exclusion criteria was used, a total of 91 patients with OPLL participated in the study. Patients' follow-up data for at least 2 years were obtained. The recovery rate of the Japanese Orthopaedic Association (JOA) scores was compared to two other classification schemes. According to the MACTC, central-sharp-type OPLL had a lower recovery rate of the JOA score than that of central-gentle-type OPLL (36.05±32.38 vs. 83.90±23.52, P≤0.05). The recovery rate of the JOA scores in the ipsilateral open-door OPLL group was significantly lower than that in the contralateral group of the lateral-steep type (36.67±41.5 vs. 88.89±17.21, P=0.04), but not of that in the lateral-gentle type. There was no significant difference in the recovery rates of the JOA scores between groups when using either existing classification scheme (P>0.05). The MACTC scheme can assist surgeons to choose the most appropriate operating procedure, and provide an accurate prognosis. If operations on central-sharp-type OPLL are not performed using both the posterior and anterior approaches, prognosis will be poor. The contralateral side should be the first choice for door opening in laminoplasty, especially for patients with lateral-steep-type OPLL. Severe OPLL may not be an absolute contraindication for the posterior approach.

Intraoperative O-arm navigation guided anterior cervical corpectomy and fusion with minimally invasive cervical pedicle screw fixation (MICEPS) for severe ossification of the cervical posterior longitudinal ligament (OPLL): A technical note

BackgroundAnterior cervical corpectomy and fusion (ACCF) with floating technique is one of the best surgical interventions for severe ossification of the posterior longitudinal ligament (OPLL). However, insufficient decompression and a thinned ossification mass often lead to poor clinical outcome. This report describes a novel floating technique with intraoperative O-arm navigation to facilitate surgical treatment of the OPLL, which has not previously been described as a therapeutic option. Case descriptionAn 82-year-old woman with myelopathy of the OPLL was referred to our hospital. Activities of daily living had been restricted by severe left arm pain, myelopathy hand, and gait disturbance for 3 years. ACCF was performed under the guidance of O-arm navigation and C-arm-free minimally invasive cervical pedicle screw fixation (MICEPS). The patient was successfully treated surgically and manual muscle test results and sensory function of the left arm had recovered fully by final follow-up at 1 year. Japanese Orthopedic Association score of the patient had improved from 10/17 to 16/17. ConclusionsIntraoperative O-arm navigation-guided ACCF with C-arm-free MICEPS is an effective technique for achieving precise decompression and strong, minimally invasive fixation. This new anterior navigation technique provides an excellent result for severe OPLL without the risk of adverse events from intraoperative radiation.

A novel anterior decompression technique for kyphosis line (K-line) ossification of posterior longitudinal ligament (OPLL): vertebral body sliding osteotomy

Conventional anterior cervical corpectomy and fusion (ACCF) for cervical ossification of the posterior longitudinal ligament (OPLL) is associated with a high incidence of surgery-related complications. A novel anterior decompression technique [vertebral body sliding osteotomy (VBSO)] has been developed to prevent such complications and achieve effective anterior decompression for severe OPLL patients. The purpose of this study was to describe the procedure of novel surgical technique and to evaluate the long-term surgical outcomes. Between 2012 and 2014, 24 patients underwent VBSO for treatment of cervical myelopathy caused by severe OPLL. Operation time, estimated blood loss (EBL), neurologic outcomes and perioperative complications were investigated. Various radiographic parameters such as the preoperative canal occupying ratio, postoperative canal widening, and preoperative and postoperative cervical sagittal alignment were also measured. Minimum follow-up was 24 months. The mean Japanese Orthopaedic Association score for cervical myelopathy (C-JOA score) improved from 12.4±2.9 preoperatively to 16.0±1.4 at the final follow-up (P<0.05). The mean recovery rate of the C-JOA score at the final follow-up was 68.65%±17.80%. The mean operating time was 130.7±21.0 minutes and the EBL was 176.3±38.0 mL. There were no perioperative complications. Pseudarthrosis was detected in two cases at 12 months postoperatively. The average spinal canal compromised ratio by OPLL decreased from 64.0%±15.0% preoperatively to 15.5%±12.2% postoperatively (P<0.05), with an average postoperative canal widening of 5.15±1.39 mm. Novel anterior decompression technique termed VBSO may be an effective and safe surgical option for anterior decompression surgery in patients with severe cervical OPLL. Since, VBSO does not involve a direct manipulation of the OPLL mass or dissection of the interspace between the OPLL and dura mater, this may significantly decrease the incidence of surgery-related complications, operation time, and intraoperative blood loss.

Analysis of the spinal cord angle for severe cervical ossification of the posterior longitudinal ligament: comparison between anterior controllable antedisplacement and fusion (ACAF) and posterior laminectomy.

To investigate the changes of spinal cord angle between anterior controllable antedisplacement and fusion (ACAF) and posterior laminectomy in treating severe ossification of the posterior longitudinal ligament (OPLL). Seventy-one patients with cervical OPLL were enrolled. Patients in this study were divided into group A and group P. Japanese Orthopaedic Association (JOA) score was utilized to evaluate the neurological function. Radiological assessments included the spinal cord angle, Cobb angle, and area of the spinal cord. Surgery-related complications were also recorded. At the final follow-up, patients in group A had better recovery of local and whole cord angle, and the area of the cord than those in group P (all p < 0.05). A strong correlation between the change of local cord angle and the recovery of the spinal cord area was observed (r = - 0.867, p < 0.05). In addition, patients in group P had worse Cobb angle (9.15° ± 1.10°) than in group A (18.58° ± 0.73°) (p < 0.05). The final mean JOA score and its improvement rate were better in the group A than in group P (p < 0.05). During the follow-up, 15.15% patients in group P experienced surgery-related complications and 7.89% in group A. This present study revealed that ACAF can achieve better recovery of the expansion of the spinal cord, spinal cord alignment, and Cobb angle, with better postoperative JOA score and less complications, compared with posterior laminectomy in treating severe cervical OPLL. These slides can be retrieved under Electronic Supplementary Material.

Evaluating the differences between 1D, 2D, and 3D occupying ratios in reflecting the JOA score in cervical ossification of the posterior longitudinal ligament

To compare the differences between the one-dimensional (1D) length, two-dimensional (2D) area, and three-dimensional (3D) volume occupying ratios, and to assess the difference between the central and peripheral types of ossification of the posterior longitudinal ligament (OPLL). In total, 60 patients were included in this study, and 1D and 2D occupying ratios were obtained using Centricity PACS (GE Healthcare), while a 3D model was created using MIMICS® (Materialise, Leuven, Belgium). Clinical symptoms were measured preoperatively by the modified Japanese Orthopedic Association (JOA) score, short-form health survey (SF-36), and neck disability index. The increased signal intensity (ISI) in T2-weighted MRI was divided into three groups: grade 0, none; grade1, limited to one disc level; or grade2, beyond one disc level. The axial view of spinal canal in CT was vertically divided into three equal parts. Then, the OPLL was categorized by central and peripheral type according to the location of most protruded tip. The 1D, 2D, and 3D occupying ratios had a significantly negative relationship with JOA score (r=-0.503; -0.506; -0.516, respectively). There was little difference in the JOA score between the central and peripheral types (17.15 vs. 17.12, P=0.785). The relationship with MR ISI, according to the central and peripheral type, showed no significant difference. In each multiple regression analysis, the 1D, 2D, and 3D occupying ratios were determined to have more influence on the JOA score (Beta: -0.364, -0.411, -0.462, respectively) than age, sex, most severe level, OPLL type, location type, and MR ISI. There was no difference between 1D, 2D, and 3D occupying ratios in reflecting the JOA score in cervical OPLL. Also, it is sufficient to reflect the occupying ratio in the clinical outcome without distinguishing between central and peripheral type.

Anterior Controllable Antedisplacement Fusion (ACAF) for Severe Cervical Ossification of the Posterior Longitudinal Ligament: Comparison with Anterior Cervical Corpectomy with Fusion (ACCF)

Anterior cervical corpectomy and fusion (ACCF), in which a ventral constriction is resected, can decompress myelopathy and is considered the optimal treatment for ossification of the posterior longitudinal ligament (OPLL) up to now. However, its disadvantages are incomplete decompression, high surgery- and implant-related complication rates, and extremely surgical technique demanding. Our object was to introduce anterior controllable antedisplacement fusion (ACAF), a new surgical technique to treat OPLL, and compare it with ACCF. ACAF was performed on 34 patients with spinal stenosis with myelopathy due to severe (occupying rate ≥50%) OPLL. Pre- and postoperatively, we measured decompression width and spinal canal area on cross-sectional computed tomography and morphology and anteroposterior diameter of the spinal cord at the most severely affected segment on cross-sectional magnetic resonance imaging and cross-sectional computed tomography. Japanese Orthopedic Association scoring was used to evaluate neurologic status. The ACAF group and a control group of 36 patients with ACCF were compared. Postoperatively, decompression width (17.9 ± 1.0 vs. 15.1 ± 0.8 mm; P < 0.01), spinal canal area (150.4 ± 31.6 vs. 127.0 ± 27.0 mm2; P < 0.01), and anteroposterior spinal cord diameter (5.4 ± 0.6 vs. 5.0 ± 1.1 mm; P < 0.05) were significantly greater in the ACAF group. At 6 months,mean Japanese Orthopedic Association score was significantly better in the ACAF group (15.4 ± 0.9 vs. 14.5 ± 2.5 points; P= 0.04). ACAF, providing adequate decompression of the spinal cord and good outcomes, is a well choice in the treatment of spinal stenosis due to severe OPLL.

Distribution of ossified spinal lesions in patients with severe ossification of the posterior longitudinal ligament and prediction of ossification at each segment based on the cervical OP index classification: a multicenter study (JOSL CT study)

BackgroundIn patients with ossification of the posterior longitudinal ligament (OPLL) in the cervical spine, it is well known that the thoracic ossified lesions often coexist with the cervical lesions and can cause severe myelopathy. However, the prevalence of OPLL at each level of the thoracic and lumbar spinal segments is unknown. The aims of this study were to investigate how often OPLL occurs at each level in the thoracolumbar spine in patients with a radiological diagnosis of cervical OPLL and to identify the spinal levels most likely to develop ossification.MethodsData were collected from 20 institutions in Japan. Three hundred and twenty-two patients with a diagnosis of cervical OPLL were included. The OPLL index (OP index), defined as the sum of the vertebral body and intervertebral disc levels where OPLL is present, was used to determine disease severity. An OP index ≥20 was defined as severe OPLL. The prevalence of OPLL at each level of the thoracic and lumbar spinal segments was calculated.ResultsWomen were more likely to have ossified lesions in the thoracolumbar spine than men. Severe OPLL was significantly more common in women than in men (20% vs. 4.5%). For thoracic vertebral OPLL, the most frequently affected was the T1 segment in both men and women, followed by the T1/2 and T3/4 intervertebral levels in men and women, respectively. Ossified lesions were frequently seen at the intervertebral and vertebral levels around the cervicothoracic and thoracolumbar junctions in men with severe OPLL, whereas OPLL was more diffusely distributed in the thoracic spine in women with severe OPLL.ConclusionThoracolumbar OPLL occurred most often at T1 in men and at T3/4 in women. In severe OPLL cases, although ossified lesions were frequently seen at the intervertebral and vertebral levels around the cervicothoracic and thoracolumbar junctions in men, OPLL could be observed more diffusely in the thoracic spine in women.

Anterior controllable antidisplacement and fusion surgery for the treatment of multilevel severe ossification of the posterior longitudinal ligament with myelopathy: preliminary clinical results of a novel technique

PurposeAlthough anterior and posterior decompression surgery are both reported to treat patients with myelopathy caused by ossification of the posterior longitudinal ligament (OPLL). The surgical strategy of the disease is still controversial when the OPLL is multilevel and severe. This present study reports the preliminary clinical results of a novel technique named anterior controllable antidisplacement and fusion (ACAF) for the treatment of multilevel-severe OPLL with myelopathy.MethodsA series of 15 patients with cervical myelopathy caused by compression of multilevel severe OPLL were enrolled. All the patients underwent ACAF after thorough surgical designing based on preoperative imaging. The patients were followed for a mean follow-up duration of 9 months in this study. The main surgical procedures include discectomy of the involved levels, thinning of the anterior part of the involved vertebrae, intervertebral cages, anterior plate and screws installation, bilateral osteotomies of the vertebrae, and antedisplacement of the vertebrae-OPLL complex (VOC). The Japanese Orthopaedic Association (JOA) scales, Visual Analog Scale (VAS) were studied. And the pre- and postoperative radiological parameters, and surgical complications were also investigated.ResultsPostoperative CT and MRI showed complete decompression of the cord by antidisplacement of the VOC. Restoration of neurological defects was confirmed at the last follow-up assessment. Bone fusion was confirmed by CT at 6 months follow-up. No specific complications were identified that were associated with this technique.ConclusionsThe present study demonstrates that excellent postoperative outcome can be achieved with the use of the ACAF. Though further study is required to confirm the conclusion, this novel technique has the potential to serve as an alternative surgical technique for the treatment of cervical OPLL.Graphical abstractThese slides can be retrieved under Electronic Supplementary Material.

Radiological risk factors for progression of ossification of posterior longitudinal ligament following laminoplasty

Background ContextResearch shows the progression of ossification of the posterior longitudinal ligament (OPLL) following decompressive surgery for cervical myelopathy, particularly in cases presenting with continuous or mixed radiographic types. To date, no study has investigated OPLL progression within each motion segment. PurposeTo evaluate progression of cervical OPLL in each motion segment using a novel system of classification, and to identify risk factors for OPLL progression following laminoplasty. Study Design/SettingRetrospective case series. Patient SampleThis study included 34 patients (86 segments) with cervical myelopathy secondary to OPLL. Outcome MeasuresClinical and radiological data (plain radiographs and computed tomography [CT]) were obtained. MethodsClinical data from 34 patients (86 segments) with cervical myelopathy secondary to OPLL were evaluated retrospectively. All subjects had undergone laminoplasty at a single center. Sagittal reconstructive CT images were used to measure OPLL thickness in each segment. Ossified masses were classified into four types according to the degree of disc space involvement: type 1 (no involvement); type 2 (involving disc space but not crossing); type 3 (crossing disc space but not fused); and type 4 (complete bridging). Range of motion (ROM) for each segment was measured using dynamic radiographs. Statistical analyses were performed to determine the degree of OPLL progression according to the four disc space involvement types and ROM. ResultsMean OPLL progression was significantly higher in types 2 (1.3 mm) and 3 (1.5 mm) than in type 1 (0.5 mm) (p<.001). Severe progression (change in thickness >2 mm) was more frequent in types 2 (8 of 29) and 3 (7 of 16) than in types 1 (1 of 35) or 4 (0 of 6) (p=.002). In types 2 or 3, ROM>5° was correlated with severe OPLL progression (52% vs. 8%; p=.035). ConclusionsType 2 or 3 disc involvement and segmental ROM>5° were risk factors for OPLL progression. Classification of cervical OPLL according to disc involvement may help predict OPLL progression following laminoplasty. Close follow-up is warranted in cases of type 2 or 3 with greater segmental motion.

Enlarged anterior cervical diskectomy and fusion in the treatment of severe localised ossification of the posterior longitudinal ligament.

BackgroundSevere localised ossification of the posterior longitudinal ligament (OPLL) should be directly removed by anterior approach, but the exposure during anterior cervical diskectomy and fusion (ACDF) is restricted and may increase the risk of a cerebrospinal fluid (CSF) leak. Corpectomy is facilitated to extirpate the ossification, but it is relatively more invasive. The purpose of this study was to investigate the feasibility and clinical outcome of enlarged ACDF in treating severe localised OPLL.MethodsTwenty-four selective patients with severe localised OPLL who underwent enlarged ACDF from January 2011 to July 2013 were retrospectively investigated. The Japanese Orthopaedic Association (JOA) scales, visual analogue scale (VAS), occupying rate (OR), fused segment height (FSH), sagittal segmental alignment (SSA), range of motion (ROM), and complications were investigated.ResultsAfter a mean 34.9-month follow-up, the mean JOA score increased from 9.5 ± 1.4 preoperatively to 14.1 ± 1.5 at the final follow-up (p < 0.05), while OR decreased from 58.9 ± 6.1 % pre- to 10.6 ± 5.5 % postoperatively (p < 0.05). The average VAS was 6.1 ± 1.8 preoperatively and 2.1 ± 1.4 at the final follow-up (p < 0.05). The SSA angles at the final follow-up increased 2.2° compared to the preoperative values (p < 0.05). The mean FSH increased 2.4 mm from pre- to postoperatively, but decreased 2.7 mm from postoperatively to final follow-up. The cervical ROM was not obviously reduced at the final follow-up (p > 0.05) because only one level was fixed. There were three cases of cerebrospinal fluid leakage, one case of haematoma, and one case showed transient neurological deterioration.ConclusionsEnlarged ACDF is an effective procedure for treating selective patients with severe localised OPLL. Using this technique, the retrovertebral OPLL can be removed through a one-level diskectomy and a corpectomy can be avoided.Trial registrationThis study has been registered with the ResearchRegistry and the unique identifying number is researchregistry1365 (K2015-022-04). It was retrospectively registered at 21 June 2016 and the first participant to the trial was at 4 January 2011.Electronic supplementary materialThe online version of this article (doi:10.1186/s13018-016-0449-z) contains supplementary material, which is available to authorized users.

Quality of Life and Functional Outcomes after Surgical Decompression in Patients with Cervical Ossification of the Posterior Longitudinal Ligament: Results from the Prospective, Multicenter AOSpine International Study on 479 Patients

Introduction Degenerative cervical myelopathy (DCM) is an umbrella term that includes cervical spondylotic myelopathy, ossification of the posterior longitudinal ligament (OPLL) and other forms of degenerative changes to the spinal axis. The surgical management of OPLL can be technically challenging for spine surgeons and may result in a higher incidence of perioperative complications than surgery for other forms of DCM. It is unclear whether surgery is equally effective and safe in patients with OPLL as it is in other forms of DCM. This study aims to compare the impact of cervical decompressive surgery on functional status and Quality of Life (QOL) outcomes in patients with OPLL and those with other forms of DCM. Material and Methods 479 surgical patients with symptomatic DCM were prospectively enrolled in the CSM-International study at global 16 sites. Patients’ functional and neurological status were evaluated using the modified Japanese Orthopedic Assessment scale (mJOA) and the Nurick score. QOL was assessed using patient-reported outcome measures, including the Neck Disability Index (NDI) and the Short- Form 36 (SF-36) Health Survey. Improvements in functional status and QOL were assessed between baseline and 1- and 2-year follow-ups, and relative gains were compared between patients with and without OPLL. A sub-analysis was conducted in patients with “severe” myelopathy (a preoperative mJOA &lt; 12) to determine whether surgical outcomes differed between patients with severe OPLL and those with other forms of severe DCM. Improvements in preoperative functional status and QOL at 2-years follow-up were compared between the two diagnosis groups, while controlling for relevant confounding variables. Results Of 479 patients, 135 (28.2%) exhibited evidence of OPLL and 344 (71.8%) displayed other forms of degenerative changes. There were no significant differences in demographics, surgical approach, or baseline severity scores between patients with OPLL and those with other forms of DCM. Patients with OPLL achieved similar functional outcomes at 1- and 2-years following surgery when compared with patients with other forms of DCM. With respect to QOL, the NDI and most subscales of the SF-36, there were no differences between the two diagnosis groups. However, the SF-36 Role Limitation Physical subscale ( p = 0.0091) at 1-year and the SF-36 Social Functioning subscale at 1- and 2-years ( p = 0.014, p = 0.018) were significantly lower in OPLL patients. In patients with severe myelopathy (preoperative mJOA &lt; 12), 49 (28.65%) presented with OPLL and 122 (71.35%) with other forms of DCM. There were comparable improvements between preoperative and 2-year postoperative scores across all outcome measures (mJOA, Nurick, NDI, and SF-36) in patients with severe myelopathy due to OPLL and other forms of DCM. Finally, there was a significantly higher rate of perioperative complications in the OPLL group ( p = 0.054). This significant difference was mainly due to a higher incidence of superficial infection ( p = 0.0067), new neck pain ( p = 0.079) and dural tear ( p = 0.076) in the OPLL group. However, rates of neurological complication did not significantly differ ( p = 0.73). Conclusion Surgical decompression for the treatment of OPLL results in significant improvements in functional status and QOL, comparable to gains seen in other forms of DCM.

Complications corner: Quadriplegia after a minor hyperextension injury with severe OPLL teaching case and illustrative images.

Background:A previously healthy and asymptomatic male surviving well into his ninth decade (86 years of age) was rendered immediately and completely quadriplegic after a minor fall associated with cervical hyperextension.Methods:Since he was unable to undergo a magnetic resonance (MR) scan due to the presence of a cardiac pacemaker, a non-contrast computed tomography (CT) was performed. This study demonstrated extremely severe cervical spinal canal stenosis secondary to previously undiagnosed ossification of the posterior longitudinal ligament (OPLL) resulting in marked spinal cord compression between C5 and C6.Results:Secondary to his severe and irreversible quadriplegia, the patient elected not to undergo any intervention; he expired 4 days later. Had his deficit not been so severe, and had he been diagnosed earlier and undergone prophylactic/preventive posterior decompression (e.g. laminectomy C4-C7) sufficient to allow his cord to migrate dorsally, his irreversible quadriplegic deficit might have been avoided.Conclusions:Older patients with symptoms of progressive myelopathy should undergo early cervical MR (or CT if they have a pacemaker) screening looking for “silent” cord compression due to stenosis, spondyloarthrosis, and/or OPLL. This case highlights the devastating consequences of even a mild hyperextension injury in a patient harboring extremely severe but previously undiagnosed OPLL. Devastating life-threatening or life-ending injuries may be avoided by maintaining a low threshold for performing screening” cervical studies in elderly patients with vague complaints that might signal the onset of myelopathy.

Cerebrospinal Fluid Leakage during Anterior Approach Cervical Spine Surgery for Severe Ossification of the Posterior Longitudinal Ligament: Prevention and Treatment

The prevention and treatment of the common complication of cerebrospinal fluid leakage (CSFL) during anterior approach cervical spine surgery for severe ossification of the posterior longitudinal ligament (OPLL) is documented. A retrospective analysis of 47 patients with severe cervical OPLL aged 39 to 73 years (average, 56.4 years) who underwent anterior operations was conducted. All patients were classified as local or segmental types based on the thickness of the ossified mass (>5 mm) and canal stenosis rates exceeding 50%. Fifteen cases underwent discectomy and fusion and 32 cases corpectomy and fusion. Preoperative CT images were analyzed for operation breakthrough and decompression range. During surgery, the ossified mass was excised or floated and the arachnoid reserved in order to reduce dural damage. Sutures coupled with gelatin sponge or muscle pedicle were applied to repair dural defects. After surgery, patients were confined to bed to allow for drainage or puncture. Fifteen cases of dural defects were recognized intraoperatively. Postoperatively, 5 patients developed CSFL. Partially cut dura with intact arachnoid occurred in one patient who developed a CSF pseudocyst. No cases required secondary operations or shunt placement and all exhibited good wound healing, with JOA scores increasing from 7.30 ± 1.08 to 13.70 ± 0.81 points and improvement rates of 65.98% ± 7.35%. During anterior surgical treatment for severe OPLL, CSFL can be prevented and treated through careful analysis of CT images, meticulous operative technique, careful handling of the ossified mass, and intra-operative repair of dural damage.