Multilevel Ossification Of The Posterior Longitudinal Ligament Research Articles

Review/Perspective: Incidence and treatment of CSF leaks/dural tears (DT) occurring during anterior cervical surgery

Background: The incidence of cerebrospinal fluid (CSF) leaks/dural tears (DT) occurring during anterior cervical diskectomy and fusion (ACDF) are typically relatively low. However, this frequency markedly increases when anterior corpectomy and fusion (ACF) are performed to address ossification of the posterior longitudinal ligament (OPLL). Methods: The reported frequencies of CSF leaks/DT occurring during elective ACDF (i.e. exclusive of trauma), ranges from 0.24% to 1.7%. Notably, this incidence substantially rises for multilevel ACF addressing anterior OPLL, markedly varying from 3.4 - 44.7%. Results: The classical risks of anterior cervical CSF leaks/DT with anterior cervical surgery may be minimized utilizing an operating microscope. For OPLL, careful evaluation of preoperative non-contrast CT studies is critical, especially to document whether any of the 3 signs of dural penetrance is present. Here, posterior operative choices should be strongly considered in the presence of sufficient lordosis and/or a Positive K Line (+ K Line) as this will avoid an anterior cervical CSF leak/dural fistula. Alternatively, for patients with kyphosis and a Negative K Line (- K Line), preoperative anticipation and planning to treat an intraoperative anterior CSF leak/DT (i.e. direct anterior primary dural graft repair with 7-0 Gore-Tex sutures, microdural staples, microfibrillar collagen, wound-peritoneal shunt, and lumbar drain or lumboperitneal shunt) are essential in the course of performing direct anterior OPLL resection. Conclusion: The incidence of anterior cervical CSF leaks/DT is relatively low (i.e. range 0.24 - 1.7%) where ACDF is performed for disc disease/spur/spondylosis exclusive of OPLL. However, where ACF is performed for multilevel OPLL, the risk of CSF Leaks/DT is substantially higher (i.e. range 4.3-44.7%).

The CT Classification of Multilevel Cervical Ossification of the Posterior Longitudinal Ligament to Guide Hybrid Anterior Controllable Antedisplacement and Fusion vs. Posterior Laminoplasty.

For precise and minimally invasive treatment of ossification of the posterior longitudinal ligament of the cervical spine, the lifting segment is minimized, anterior controllable antedisplacement and fusion (ACAF) was refined and improved. In addition, the development of appropriate surgical procedures for the ossification of each segment was rarely reported. Therefore, this study aimed to compare the efficacy and safety of hybrid anterior controlled antedisplacement fusion (Hybrid ACAF) with laminoplasty for multilevel ossification of the posterior longitudinal ligament (OPLL). Between May 2018 and May 2021, 70 patients with multilevel OPLL were divided into a hybrid ACAF group and a laminoplasty group according to surgical methods. All patients were followed up for at least 1 year. Japanese Orthopaedic Association (JOA) score and recovery rate (JOARR), (VAS, NDI) score and C2-C7 Cobb angle, the sagittal vertical axis of the neck (SVA), and complications (cerebrospinal fluid leakage, C5 paralysis, etc.) were compared between the two groups by t test or non-parametric test. The operation time of hybrid ACAF was longer. C5 paralysis and axial pain were more common in the laminoplasty group, while dysphagia and hoarseness were more common in the hybrid ACAF group. At the last follow-up, the hybrid ACAF group had better recovery and maintenance of cervical lordosis and sagittal plane balance and a higher JOA score and recovery rate than the laminoplasty group. Hybrid ACAF can reduce the number of vertebral bodies and expand the decompression range, which is safe, effective, and tailored to local conditions. Compared with laminoplasty, hybrid ACAF is a precise alternative for patients with OPLL.

Comparative Analysis of Postoperative Sagittal Balance in Expansive Open-Door Laminoplasty versus Laminectomy with Fusion for Multilevel Ossification of Posterior Longitudinal Ligament: A Retrospective Study.

BACKGROUND This single-center study included 80 patients with multilevel cervical ossification of the posterior longitudinal ligament (OPLL) and aimed to compare postoperative sagittal balance following treatment with expansive open-door laminoplasty (LP) vs total laminectomy with fusion (LF). MATERIAL AND METHODS Data of 80 patients with multilevel OPLL treated with LP vs LF between January 2017 and January 2022 were retrospectively analyzed. The basic data, cervical sagittal parameters, and clinical outcomes of the patients were counted in the preoperative and postoperative periods, and complications were recorded. Forty patients underwent LP and 40 underwent LF. Cervical sagittal parameters were compared between and within the 2 groups. Clinical outcomes and complications were compared between the 2 groups. RESULTS At last follow-up, the postoperative C2-C7 Cobb angel, T1 slope (T1S), and C7 slope (C7S) were significantly higher in the LF group than in the LP group (P<0.001). C2-C7 SVA (cSVA) was slightly higher in the LF group (P>0.05) and significantly higher in the LP group (P<0.05). The incidence of postoperative complications in the LP group was significantly lower than in the LF group (P=0.02). The postoperative scores on the Visual Analog Scale (VAS), Neck Disability Index (NDI), and Japanese Orthopedic Association (JOA) were significantly improved in both groups (P<0.001). CONCLUSIONS Both procedures had good outcomes in neurological improvement. After posterior surgery, the cervical vertebrae all showed a tilting forward. Compared to LP, LF may change cervical balance in Cobb angel, T1S. LF has better efficacy in improving cervical lordosis compared with LP. Patients with high T1 slope after surgery may has more axial pain.

Endoscopic Posterior Cervical Decompression for Ossified Posterior Longitudinal Ligament: A Technical Note.

Ossification of the posterior longitudinal ligament (OPLL) may cause cervical myelopathy. In its multilevel form, it may not be easy to manage. Minimally invasive endoscopic posterior cervical decompression may be an alternative to traditional laminectomy surgery. Thirteen patients with multilevel OPLL and symptomatic cervical myelopathy were treated with endoscopic spine surgery from January 2019 to June 2020. In this consecutive observational cohort study, pre- and postoperative Japanese Orthopaedic Association (JOA) score and Neck Disability Index (NDI) were analyzed at a final follow-up of 2 years postoperatively. There were 13 patients consisting of 3 women and 10 men. The patient's average age was 51.15 years. At the final 2-year follow-up, the JOA score improved from a preoperative value of 10.85 ± 2.91 to 14.77 ± 2.13 postoperatively (P < 0.001). The corresponding NDI scores decreased from 26.61 ± 12.88 to 11.12 ± 10.85 (P < 0.001). There were no infections, wound complications, or reoperations. Direct posterior endoscopic decompression for multilevel OPLL is feasible in symptomatic patients when executed at a high skill level. While 2-year outcomes were encouraging and on par with historic data obtained with traditional laminectomy, future studies will need to show whether any long-term shortcomings exist.

Factors Affecting the Surgical Outcomes of Patients Treated With "de-tension" Surgical Strategy for Multilevel Ossification of the Posterior Longitudinal Ligament in the Thoracic Spine: A Minimum 2-year Follow-Up Study of 83 Patients in a Single Center.

Retrospective cohort study. To describe the clinical characteristics and surgical outcomes of patients with multilevel-ossification of the posterior longitudinal ligament (mT-OPLL), and to identify risk factors for unfavorable outcomes. Patients who were diagnosed with mT-OPLL and underwent one-stage thoracic posterior laminectomy combined with selective OPLL resection, spinal cord de-tension, and fusion surgery between August 2012 and October 2020 were recruited. Patients' demographic-, surgical- and radiological-related parameters were collected and analyzed. Neurological status was evaluated with mJOA score, and recovery rate (RR) was calculated using the Hirabayashi formula. According to RR, patients were divided into a favorable outcome group (FOG, RR ≥50%) and an unfavorable outcome group (UOG, RR <50%). Univariate and multivariate analyses were used to compare the difference between the 2 groups and to identify risk factors for unfavorable outcomes. A total of 83 patients were included, with an average age of 50.6 ± 8.3 years. Cerebrospinal fluid leakage (60.2%) and transient neurological deterioration (9.6%) were the most common complications. The average mJOA score improved from preoperative 4.3 ± 2.2 to 9.0 ± 2.4 at the last follow-up, and the mean RR was 74.9 ± 26.3%. Disease duration, preoperative nonambulatory status, and the number of decompressed levels were identified as potential risk factors by Univariate analysis (all P < .05). Multivariate analysis showed that the preoperative disease duration and nonambulatory status were independent risk factors for unfavorable outcomes. Long disease duration and nonambulatory status before surgery were independent risk factors for unfavorable outcomes.

Multilevel ossification of the posterior longitudinal ligament causing cervical myelopathy: An observational series of North American patients.

Few studies regarding ossification of the posterior longitudinal ligament (OPLL) outside of Asia currently exist in the literature. A set of patients with multilevel cervical OPLL causing symptomatic myelopathy or radiculopathy from a North American sample is analyzed. The objective of this study was to describe the demographics, radiographic findings, and surgical outcomes of a cohort of North American patients with degenerative spondylosis presenting for operative management of multilevel (>3 segments) cervical OPLL. Forty-three patients diagnosed with multilevel cervical OPLL and degenerative spondylosis presenting with symptomatic cervical myelopathy or radiculopathy were surgically treated over a 9-year period at a single tertiary care academic medical center. Radiographic measurements were performed on preoperative computed tomography and magnetic resonance imaging images of the cervical spine. Clinical outcomes included pre- and postoperative Nurick scores, 90-day readmission, complication, and revision surgery rates. The mean age was 66.1 ± 10.9 years with a mean latest follow-up time of 32.7 ± 16.4 months. Most patients had previous diagnoses of obesity (70.7%) and hypertension (55.8%). At least one-quarter of patients were diagnosed with type 2 diabetes (34.9%), hyperlipidemia (41.9%), cardiovascular disease (25.6%), or chronic kidney disease (25.3%). The most common OPLL subtype was segmental (39.5%) and spanned a mean of 3.54 ± 1.48 segments. Myelopathic symptoms were present in 88.4% of patients. All patients experienced significant neurologic improvement at 3-week and latest follow-up (P < 0.001 for both). Obesity, diabetes, and other metabolic derangements in patients with existing cervical spondylosis may be risk factors for a particularly aggressive form of multilevel OPLL. Various operative approaches may be employed to achieve adequate neurologic recovery. Further workup for OPLL in patients with these risk factors may prove beneficial to ensure appropriate operative management.

The surgical strategy for multilevel massive ossification of the posterior longitudinal ligaments.

Creating enough decompression, favorable outcome, less complication, and maintain adequate lordosis and stability in the patients with cervical myelopathy due to multilevel massive ossification of the posterior longitudinal ligament (OPLL) still poses a challenge for surgeons. The aim of our study is to retrospectively evaluate our patients and try to seek a better surgical strategy. Between 2015 and 2019, 55 consecutive patients with multilevel massive OPLL underwent surgical treatment. Among these, 40 patients were treated with cervical laminectomy and then anterior decompression, fusion, and fixation (ADF), which was defined as group 1, and 15 patients were treated with cervical laminectomy and fixation simultaneously, which was defined as group 2. The patient's radiographic characteristics and postoperative outcomes were evaluated. Better postoperative cervical sagittal lordosis and less long-term axial pain was achieved in group 1 (p < 0.001), though the functional outcome had no significant difference. In the multivariable analysis, anterior fixation accounts for independent factors for better cervical sagittal alignment (p < 0.001). No complications directly associated with cervical laminectomy were observed. In patients with cervical multilevel massive OPLL, laminectomy at compression level and then ADF depended on the severity and range of compression, but corpectomy of not more than two vertebral bodies is suggested, except K-line (+) and long-segment massive OPLL majorly involving the C2 and posterior laminectomy above and below the OPLL-affected levels with posterior fixation simultaneously.

New anterior controllable antedisplacement and fusion surgery for cervical ossification of the posterior longitudinal ligament: a biomechanical study.

The traditional anterior approach for multilevel severe cervical ossification of the posterior longitudinal ligament (OPLL) is demanding and risky. Recently, a novel surgical procedure-anterior controllable antedisplacement and fusion (ACAF)-was introduced by the authors to deal with these problems and achieve better clinical outcomes. However, to the authors' knowledge, the immediate and long-term biomechanical stability obtained after this procedure has never been evaluated. Therefore, the authors compared the postoperative biomechanical stability of ACAF with those of more traditional approaches: anterior cervical discectomy and fusion (ACDF) and anterior cervical corpectomy and fusion (ACCF). To determine and assess pre- and postsurgical range of motion (ROM) (2 Nm torque) in flexion-extension, lateral bending, and axial rotation in the cervical spine, the authors collected cervical areas (C1-T1) from 18 cadaveric spines. The cyclic fatigue loading test was set up with a 3-Nm cycled load (2 Hz, 3000 cycles). All samples used in this study were randomly divided into three groups according to surgical procedures: ACDF, ACAF, and ACCF. The spines were tested under the following conditions: 1) intact state flexibility test; 2) postoperative model (ACDF, ACAF, ACCF) flexibility test; 3) cyclic loading (n = 3000); and 4) fatigue model flexibility test. After operations were performed on the cadaveric spines, the segmental and total postoperative ROM values in all directions showed significant reductions for all groups. Then, the ROMs tended to increase during the fatigue test. No significant crossover effect was detected between evaluation time and operation method. Therefore, segmental and total ROM change trends were parallel among the three groups. However, the postoperative and fatigue ROMs in the ACCF group tended to be larger in all directions. No significant differences between these ROMs were detected in the ACDF and ACAF groups. This in vitro biomechanical study demonstrated that the biomechanical stability levels for ACAF and ACDF were similar and were both significantly greater than that of ACCF. The clinical superiority of ACAF combined with our current results showed that this procedure is likely to be an acceptable alternative method for multilevel cervical OPLL treatment.

Instrumented fusion versus instrumented non-fusion following expansive open-door laminoplasty for multilevel cervical ossification of the posterior longitudinal ligament.

To compare the outcomes of expansive open-door laminoplasty with instrumented fusion (ELIF) and expansive open-door laminoplasty with instrumented non-fusion (ELINF) for multilevel cervical ossification of the posterior longitudinal ligament (OPLL). Patients who underwent ELIF or ELINF due to multilevel cervical OPLL from June 2013 to June 2019 were identified. Clinical and radiological outcomes were compared between the two groups. A total of 78 patients were enrolled in this study with a minimum follow-up of 24months, including 42 patients in the ELIF group and 36 patients in the ELINF group. At the final follow-up, sagittal vertical axis (SVA) and C2-C7 Cobb angle in the ELIF group were significantly better than those in the ELINF group, and cervical range of movement (ROM) in the ELIF group decreased significantly than that in the ELINF group. The incidence of OPLL progression at the final follow-up was 4.76% (2/42) in the ELIF group and 27.78% (10/36) in the ELINF group. Postoperative Japanese Orthopaedic Association (JOA) score, neck disability index (NDI), and visual analog scale (VAS) score improved significantly in each group, but JOA score and recovery rate (RR) in the ELIF group were significantly better than those in the ELINF group at the final follow-up. When K-line was positive, the difference in the final JOA score between the two groups was not significant, but the RR in the ELIF group was significantly better than that in the ELINF group. When K-line was negative, the final JOA score and RR in the ELIF group were significant higher than those in the ELINF group. ELIF and ELINF were two effective surgical procedures for treating multilevel cervical OPLL. However, ELIF was superior to ELINF due to better postoperative JOA score and RR, significant improvement of C2-C7 Cobb angle and maintenance of SVA, and suppressant effect on OPLL progression, especially for patients with K-line (-) OPLL.

Bridging the cervicothoracic junction during posterior cervical laminectomy and fusion for the treatment of multilevel cervical ossification of the posterior longitudinal ligament: a retrospective case series

BackgroundThe purpose of this study was to investigate the surgical efficacy of crossing the cervicothoracic junction during posterior cervical laminectomy and fusion for the treatment of multilevel cervical ossification of the posterior longitudinal ligament (OPLL).MethodsFrom October 2009 to October 2017, 46 consecutive patients with multilevel cervical OPLL underwent posterior cervical laminectomy and crossing the cervicothoracic junction fusion were obtained in the study. Their medical records were retrospectively collected. Cervical lordosis and cervical sagittal balance were used to assess radiographic outcomes. Japanese Orthopedic Association (JOA), axial symptom, C5 root palsy, blood loss, and operation time were used to assess clinical outcomes. The mean follow-up period was 20.7 ± 8.3 months.ResultsThe operation time was 205.2 ± 39.8 min and the intraoperative blood loss was 352.2 ± 143.7 ml. Analysis of the final follow-up data showed significant differences in JOA score (P < 0.01), C2-C7 lordosis angle (P < 0.01), and C2-C7 SVA (P < 0.01). CT confirmed that grafted bone was completely fused in all patients and progression of OPLL was observed in two patients (4.3%) at final follow-up. No adjacent segment disease (ASD) or instrument failure occurred in any patients.ConclusionsCervical laminectomy and crossing the cervicothoracic junction fusion are effective and safe methods to treat multilevel cervical OPLL. Randomized controlled studies compared constructs ending at cervical vertebrae or thoracic vertebrae are needed to confirm these results.

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.

Anterior Cervical Corpectomy with Fusion versus Anterior Hybrid Fusion Surgery for Patients with Severe Ossification of the Posterior Longitudinal Ligament Involving Three or More Levels: A Retrospective Comparative Study

Various studies have found a high incidence of early graft dislodgement after multilevel corpectomy. Although a hybrid fusion technique was developed to resolve implant failure, the hybrid and conventional techniques have not been clearly compared in terms of perioperative complications in patients with severe ossification of the posterior longitudinal ligament (OPLL) involving three or more levels. The purpose of this study was to compare clinical and radiologic outcomes between anterior cervical corpectomy with fusion (ACCF) and anterior hybrid fusion for the treatment of multilevel cervical OPLL. We therefore retrospectively reviewed the clinical and radiologic data of 53 consecutive patients who underwent anterior fusion to treat cervical OPLL: 30 underwent ACCF and 23 underwent anterior hybrid fusion. All patients completed 2 years of follow-ups. Implant migration was defined as subsidence > 3 mm. There were no significant differences in demographics or clinical characteristics between the ACCF and hybrid groups. Early implant failure occurred significantly more frequently in the ACCF group (5 cases, 16.7%) compared with the hybrid group (0 cases, 0%). The fusion rate was 80% in the ACCF group and 100% in the hybrid group. Although both procedures can achieve satisfactory neurologic outcomes for multilevel OPLL patients, hybrid fusion likely provides better biomechanical stability than the conventional ACCF technique.

The Effect of Laminectomy with Instrumented Fusion Carried into the Thoracic Spine on the Sagittal Imbalance in Patients with Multilevel Ossification of the Posterior Longitudinal Ligament.

ObjectiveTo determine if there is a difference in either the cervical alignment or the clinical outcomes in cervical ossification of the posterior longitudinal ligament (OPLL) patients who underwent laminectomy with instrumented fusion (LIF) ending at C6, C7, or proximal thoracic spine for the treatment of multilevel OPLL, and to find out the appropriate distal fusion level.MethodsThis was a single‐center retrospective study. In total, 36 patients with cervical OPLL who underwent three or more level LIF in our institution between January 2015 and January 2017 were enrolled. They were divided into three groups according to their distal ends: C6 (nine females and 11 males, 60.45 ± 9.68 years old), C7 (four females and six males, 61.60 ± 10.29 years old), and T‐group (two females and four males, 64.33 ± 8.12 years old). Radiographic (compression level, classification of OPLL, occupying rate, C2‐7 cobb angle, C2‐7 sagittal vertical axis, and fusion level) and clinical outcomes (NDI score, operative time, and blood loss) were compared. Predictors of postoperative sagittal imbalance were also identified according to if the postoperative C2‐7 SVA was greater than 40 mm. The sensitivity and specificity of preoperative parameters predicting postoperative cervical stability were evaluated via the receiver operating characteristic (ROC) curve.ResultsAll patients were followed up at least 1 year. The blood loss in T group was significantly more than C6 or C7 group. The length of fusion level became significantly longer when the caudal level extended to the thoracic spine. The age, preoperative SVA, and NDI score at follow‐up were significantly greater in the imbalance group. At the final follow‐up, the cervical lordosis tended to be straight and the C2‐7 SVA tended to be greater when the caudal level of fusion was extended to upper thoracic segment. Further ROC curve analysis suggested that patients’ age had a sensitivity of 75.00%, specificity of 79.17% for cervical stability, and the AUC was 0.844 (P < 0.01), with the cutoff value for age being 66.5 years old. For preoperative SVA, the sensitivity was 58.30%, and specificity was 91.70%, with the AUC of 0.778 (P < 0.01). The cutoff value for preoperative SVA was 30.4 mm.ConclusionAlthough posterior fusion terminating in the thoracic spine was not superior to the cervical spine for patients with multilevel OPLL, for elderly patients (>67 years) with great preoperative SVA (>30 mm), terminating at C6 was recommended to limit the invasion of cervical extensor muscles, provided the decompression was adequate.

Perioperative Complications in Posterior Surgeries for Cervical Ossification of the Posterior Longitudinal Ligament: A Prospective Nationwide Investigation.

This was a prospective multicenter study. The aim of this study was to investigate the perioperative complications of posterior surgeries for the treatment of cervical ossification of the posterior longitudinal ligament (OPLL). Surgical treatment for cervical OPLL has a high risk of various complications. Laminoplasty (LAMP) and posterior decompression and instrumented fusion (PDF) are effective for multilevel cervical OPLL; however, few studies have focused on the surgical complications of these 2 procedures. We prospectively included 380 patients undergoing posterior surgeries for cervical OPLL (LAMP: 270 patients, PDF: 110 patients), and investigated the systemic and local complications, including neurological complications. We further evaluated risk factors related to the neurological complications. Motor palsy was found in 40 patients (10.5%), and motor palsy in the upper extremity was most frequent (8.9%), especially in patients who received PDF (14.5%). Motor palsies involving the lower extremities was found in 6 patients (1.6%). Regarding local complications, dural tears (3.9%) and surgical site infections (2.6%) were common. In the univariate analysis, body mass index, preoperative cervical alignment, fusion surgery, and the number of operated segments were the factors related to motor palsy. Multivariate analysis revealed that fusion surgery and a small preoperative C2-C7 angle were the independent factors related to motor palsy. Motor palsy involving the lower extremities tended to be found at early time points after the surgery, and all the patients fully recovered. Motor palsy in the upper extremities occurred in a delayed manner, and 68.8% of patients with PDF showed good recovery, whereas 81.3% of patients with LAMP showed good recovery. In posterior surgeries for cervical OPLL, segmental motor palsy in the upper extremity was most frequently observed, especially in patients who received PDF. Fusion and a small preoperative C2-C7 angle were the independent risk factors for motor palsy. Level III.

Laminoplasty versus laminectomy with fusion for treatment of multilevel cervical compressive myelopathy: an updated meta-analysis

BackgroundMultilevel cervical spondylotic myelopathy (CSM) and ossification of the posterior longitudinal ligament (OPLL) are debilitating degenerative diseases. If conservative treatment is ineffective, surgical options for multilevel CSM and OPLL include...

Single-Stage Posterior Approach for Multilevel Cervical Ossification of the Posterior Longitudinal Ligament With K-line (-) Using Thick Cervical Pedicle Screw System: A Technical Note and Preliminary Results.

Technical note, retrospective case series. The optimal surgical strategy for multilevel cervical ossification of the posterior longitudinal ligament (OPLL) with a negative kyphosis line (K-line (-)) remains controversial. We present a novel single-stage posterior approach that converts the K-line from negative to positive in patients with multilevel cervical OPLL, using a posterior thick cervical pedicle screw (CPS) system and report the procedure's outcomes and feasibility. Twelve consecutive patients with multilevel cervical OPLL and K-line (-) underwent single-stage posterior thick CPS fixation, with laminectomy and foraminal decompression. A pre-bent rod was installed to convert the K-line from negative to positive. Radiographic parameters, including the extent and occupying ratio of OPLL and the C2-C7 angle, were examined. CPS accuracy was assessed using computed tomography. The Japanese Orthopaedic Association (JOA) and visual analog scale (VAS) scores were analyzed. Quality of life was assessed using the Neck Disability Index (NDI). The mean OPLL extent was 5 vertebral body levels, and posterior decompression was performed on 4.2 segments. The average C2-C7 angle and the occupying ratio of OPLL improved from -9.0° to 14.3° and from 63% to 33%, respectively. The preoperative JOA, VAS, and NDI scores significantly improved from 8.4 to 13.3, from 7.1 to 2.2, and from 21.9 to 9.3, respectively. The K-line was converted from negative to positive in all cases. No severe complications were identified. Single-stage posterior surgery with a thick CPS system may be a reliable and effective treatment for multilevel cervical OPLL and K-line (-).

Risk factors for progression of ossification of the posterior longitudinal ligament in asymptomatic subjects.

The incidence and risk factors for the progression of ossification of the posterior longitudinal ligament (OPLL) have been previously reported in surgically and nonsurgically treated symptomatic patients. However, the correlates of OPLL progression in asymptomatic subjects with OPLL are not well characterized. This study aimed to clarify the incidence and risk factors for OPLL progression in asymptomatic subjects based on whole-body CT. The authors retrospectively reviewed 2585 healthy subjects who underwent whole-body CT at a single health center from September 2007 to December 2011. This study included asymptomatic subjects with OPLL who underwent CT scans twice with an interval of at least 5 years. Progression of OPLL was assessed based on initial and final CT scan. Subjects were divided into two groups: nonprogression (OPLL-NP) and progression (OPLL-P) groups. Clinical characteristics, bone mineral density status, OPLL types, and OPLL involvement of multiple vertebral levels between the two groups were compared. Risk factors for progression of OPLL were identified by logistic regression analysis after propensity score adjustment. Of the 109 subjects with OPLL (91 men and 18 women), 20 (18.3%) exhibited OPLL progression (OPLL-P group). Subjects in the OPLL-P group were significantly younger (p = 0.031), had higher prevalence of multilevel OPLL involvement (p = 0.041) and continuous type of OPLL (p = 0.015), and had higher uric acid (UA) levels (p = 0.004) at the time of initial CT examination compared to the OPLL-NP group. Younger age (adjusted odds ratio [aOR] 0.95, 95% CI 0.90-0.99), OPLL involvement of multiple vertebral levels (aOR 2.88, 95% CI 1.06-7.83), continuous type of OPLL (aOR 4.21, 95% CI 1.35-13.10), and higher UA levels (aOR 2.09, 95% CI 1.24-3.53) were significant risk factors for OPLL progression. Younger age, OPLL involvement of multiple vertebral levels, continuous type of OPLL, and higher UA levels are significant risk factors for OPLL progression in asymptomatic subjects.

Skip corpectomy and fusion (SCF) versus anterior controllable antedisplacement and fusion (ACAF): which is better for patients with multilevel cervical OPLL?

The aim of this study was to compare the clinical efficacy and radiological outcomes of skip corpectomy and fusion (SCF) with anterior controllable antedisplacement and fusion (ACAF) for treating multilevel ossification of the posterior longitudinal ligament (OPLL). 62 patients with multilevel OPLL who had undergone SCF or ACAF were analyzed retrospectively. Types of OPLL, occupying ratio (OR), Japanese Orthopaedic Association (JOA) score, Recovery Rate (RR), Neck Disability Index (NDI) score, Cobb's angles of C2-C7, operation time, blood loss, hospital stay, ratings for fusion assessment and complications were recorded and assessed. Postoperative C2-C7 Cobb's angle (11.1 ± 3.2° vs. 13.7 ± 2.5°; P < 0.05), NDI scores at final follow-up (14.3 ± 1.6 vs. 13.3 ± 1.3; P < 0.05), and rate of cerebral fluid (CSF) leakage (5, 16.7% vs. 0,0%; P < 0.05) were significantly better in the ACAF group. At 6months, bone graft fusion rate was significantly greater in the ACAF group (24.75% vs. 15.50%; P < 0.05). Surgical treatment of multilevel OPLL by SCF or ACAF showed no significant differences in clinical outcomes, with the exception of better NDI scores at final follow-up in ACAF. In addition, ACAF is better than SCF in terms of early bone graft fusion rate, lordotic curvature improvement, risk of CSF leakage.

Posterior approach laminectomy combined with localized resection of ossified posterior longitudinal ligament and dekyphosis for multilevel ossification of the posterior longitudinal ligament in the thoracic spine

Objective To investigate the safety and effectiveness of posterior approach laminectomy combined with localized resection of ossified posterior longitudinal ligament and dekyphosis for multilevel ossification of the posterior longitudinal ligament (OPLL) in the thoracic spine. Methods Thirty-one cases of thoracic multilevel OPLL was treated with this new technique between August of 2012 and August of 2016. Twenty-nine among the 31 cases were successfully followed up more than two years. Among these 29 cases, 9 were male and the other 20 were female, with an average age of 48.5±7.1 years. The average segment number of OPLL was 6.5±2.2 (range, 3-11). The average segment number of laminectomy was 7.9±2.5 (range, 4-13). There were 26 cases combined with ossification of the ligamentum flavum (OLF). Posterior approach laminectomy combined with localized resection of OPLL and dekyphosis for multilevel OPLL in the thoracic spine was applied to all cases. Firstly, en-bloc laminectomy was performed to all the segments of OPLL. Then the nearest segment of ossification to the kyphotic apex and the most stenotic level was selected and limitedly resected. Finally, wedge-shaped osteotomy was conducted to decrease the kyphosis. The outcomes including recovery rate of myelopathy and the radiological changes were recorded during the post-operative follow-up. Single group pre and post analysis was conducted by using paired t-test. Results Twenty-seven cases underwent one-level circumferential decompression, and the other two case underwent two-level localized resection of the ossified posterior longitudinal ligament. The average operation time was 245.2±75.1 min (range, 131-423 min). The average blood loss was 1 307.9±1 457.7 ml(range, 300-6 000 ml). The average follow-up time was 40.2±14.9 months (range, 25-69 months). The kyphotic angle of the stenotic segments decreased 11.4°±3.5° averagely after the surgery, from pre-operative 28.7°±9.6° to post-operative 17.3°±8.6°. The decreased kyphotic angle was 7.4°±3.1° at the final follow-up with an average kyphotic angel of 22.3°±10.3°. The average length of the resected ossified posterior longitudinal ligament was 11.3±3.9 mm, and the average shortening length of the spinal column was 5.0±3.0 mm (range, 0.4-13.8 mm). The pre-operative Japanese Orthopedic Association (JOA) score was 4.3±2.2 averagely (range, 1-9), and the final JOA score increased to 9.3±2.3 (rang, 3-11). The average recover rate was 85.7% (range, -100% to 100%), and the rate of excellent or good was 89.7%. Among the 29 cases, 6 cases occurred post-operative transient deterioration and regained a satisfactory recovery eventually; one case occurred post-operative paraplegia and never recovered; 19 cases occurred post-operative cerebrospinal fluid leakage and healed under conservative treatment. Conclusion For the thoracic multilevel OPLL, one-stage posterior approach laminectomy combined with localized resection of the ossified posterior longitudinal ligament and dekyphosis can significantly improve the outcomes of the myelopathy with low rate of post-operative paraplegia. Therefore, this new surgery technique is a safe and effective treatment for multilevel OPLL in thoracic spine. Key words: Thoracic vertebrae; Ossification of posterior longitudinal ligament; Spinal stenosis; Decompression, surgical

Variations in Practice among Asia-Pacific Surgeons and Recommendations for Managing Cervical Myelopathy: The First Asia-Pacific Spine Society Collaborative Study.

Study DesignSurgeon survey.PurposeTo study the various surgical practices of different surgeons in the Asia–Pacific region.Overview of LiteratureGiven the diversity among Asia–Pacific surgeons, there is no clear consensus on the preferred management strategies for cervical myelopathy. In particular, the role of prophylactic decompression for silent cervical spinal stenosis is under constant debate and should be addressed.MethodsSurgeons from the Asia–Pacific Spine Society participated in an online questionnaire comprising 50 questions. Data on clinical diagnosis, investigations and outcome measures, approach to asymptomatic and silent cervical spinal stenosis, guidelines for surgical approach, and postoperative immobilization were recorded. All parameters were analyzed by the Mantel–Haenszel test.ResultsA total of 79 surgeons from 16 countries participated. Most surgeons used gait disturbance (60.5%) and dyskinetic hand movement (46.1%) for diagnosis. Up to 5.2% of surgeons would operate on asymptomatic spinal stenosis, and 18.2% would operate on silent spinal stenosis. Among those who would not operate, most (57.1%) advised patients on avoidance behavior and up to 9.5% prescribed neck collars. For ossification of the posterior longitudinal ligament (OPLL), anterior removal was most commonly performed for one-level disease (p<0.001), whereas laminoplasty was most commonly performed for two- to four-level disease (p=0.036). More surgeons considered laminectomy and fusion for multilevel OPLL. Most surgeons generally preferred to use a rigid neck collar for 6 weeks postoperatively (p<0.001).ConclusionsThe pooled recommendations include prophylactic or early decompression surgery for patients with silent cervical spinal stenosis, particularly OPLL. Anterior decompression is primarily suggested for one- or two-level disease, whereas laminoplasty is preferred for multilevel disease.