Canal-occupying Ratio Research Articles

Anterior decompression and posterior total laminectomy with fusion for ossification of the cervical posterior longitudinal ligament.

Surgical approaches to cervical ossification of the posterior longitudinal ligament (OPLL) remain controversial. The purpose of the present study was to analyze and compare the long-term neurological recovery following anterior decompression with fusion (ADF) and posterior laminectomy and fusion with bone graft and internal fixation (PLF) based on > ten-year follow-up outcomes in a single centre. Included in this retrospective cohort study were 48 patients (12 females; mean age 55.79 years (SD 8.94)) who were diagnosed with cervical OPLL, received treatment in our centre, and were followed up for 10.22 to 15.25 years. Of them, 24 patients (six females; mean age 52.88 years (SD 8.79)) received ADF, and the other 24 patients (five females; mean age 56.25 years (SD 9.44)) received PLF. Clinical data including age, sex, and the OPLL canal-occupying ratio were analyzed and compared. The primary outcome was Japanese Orthopaedic Association (JOA) score, and the secondary outcome was visual analogue scale neck pain. Compared with the baseline, neurological function improved significantly after surgery in all patients of both groups (p < 0.001). The JOA recovery rate in the ADF group was significantly higher than that in the PLF group (p < 0.001). There was no significant difference in postoperative cervical pain between the two groups (p = 0.387). The operating time was longer and intraoperative blood loss was greater in the PLF group than the ADF group. More complications were observed in the ADF group than in the PLF group, although the difference was not statistically significant. Long-term neurological function improved significantly after surgery in both groups, with the improvement more pronounced in the ADF group. There was no significant difference in postoperative neck pain between the two groups. The operating time was shorter and intraoperative blood loss was lower in the ADF group; however, the incidence of perioperative complications was higher.

A Clinical Classification of Cervical Ossification of the Posterior Longitudinal Ligament to Guide Surgical Strategy.

A clinical classification of cervical ossification of the posterior longitudinal ligament (COPLL) was developed based on imaging findings. This study aimed to establish a clinical classification for COPLL and provide corresponding surgery strategies for each subtype. A practical and reliable classification is needed to guide the treatment of COPLL. This study retrospectively reviewed plain radiographs, computed tomography scans, and magnetic resonance images of patients diagnosed with COPLL between 2018 and 2022 at Shanghai Changzheng Hospital. The types of COPLL were classified according to the location, morphology, and canal-occupying ratio (OR) of the ossification mass. Interobserver and intraobserver reliability were evaluated using Cohen's kappa. A total of 1000 cases were included, which were classified into five types: focal type (F type), short-sequential type (S type), long-sequential type (L type), high type (H type), and mixed type (M type). In addition, each type could be classified into subtype 1 or subtype 2 according to the canal-OR. Then each type could be further classified into other subtypes according to location and morphology. The interobserver reliabilities in the first and second rounds were 0.853 and 0.887, respectively. The intraobserver reliability was 0.888. The authors classified COPLL into a system comprised of five types and several subtypes according to canal-OR, location, and morphology. Surgical strategies for each subtype are also suggested. This provides a theoretical guide for the description and surgical management of COPLL.

Surgical complications and incomplete canal widening of the vertebral body sliding osteotomy to treat cervical myelopathy.

Vertebral body sliding osteotomy (VBSO) is a surgical technique that anteriorly translates the vertebral body with compressive lesions and achieves cord decompression through canal widening. However, data on the surgical complications of VBSO are lacking. Furthermore, it has not been known whether VBSO could be a viable alternative in the treatment of cervical myelopathy even when the preoperative canal-occupying ratio (COR) is large, which seems to frequently result in incomplete canal widening. This study aimed to describe the incidence of VBSO-associated surgical complications and to evaluate the incidence and risk factors of incomplete canal widening. A total of 109 patients who underwent VBSO to treat cervical myelopathy were retrospectively reviewed. Neck pain visual analog scale, Neck Disability Index, Japanese Orthopaedic Association (JOA) scores, and surgical complications were evaluated. For radiological evaluation, C2-7 lordosis, C2-7 sagittal vertical axis, and COR were measured. Patients with a preoperative COR < 50% (n = 60) and those with a COR ≥ 50% (n = 49) were compared and logistic regression analysis was performed to identify factors associated with incomplete canal widening. The most frequent complication in the patients was mild dysphagia (7.3%). Dural tears were observed during posterior longitudinal ligament resection (n = 1) and foraminotomy (n = 1). Two patients underwent reoperation due to radiculopathy from adjacent-segment disease. Incomplete canal widening occurred in 49 patients. According to logistic regression analysis, high preoperative COR was the only factor associated with incomplete canal widening. The amount of canal widening and JOA recovery rate in the COR ≥ 50% group were significantly higher than in the COR < 50% group. Mild dysphagia was the most common complication following VBSO. Although VBSO aims to decrease the complication rate of corpectomy, it was not free of dural tears. Special care would be required during the posterior longitudinal ligament resection. Incomplete canal widening occurred in 45.0% of patients, and high preoperative COR was the only risk factor for incomplete canal widening. However, high preoperative COR would not be a contraindication for VBSO, given that favorable clinical outcomes were presented in the COR ≥ 50% group.

Clinical and radiographic features of adult calcified thoracic disc herniation: a retrospective analysis of 31 cases.

To analyze the clinical and radiographic characteristics of calcified thoracic disc herniation (CTDH) and explore the possible pathogeneses. This is a retrospective clinical review of prospectively collected imaging data based at a single institute from 2004 to 2021. Clinical and radiographic parameters of CTDH patients were retrospectively collected and analyzed. All 31 patients included presented thoracic myelopathy with a 17.05-month preoperative disease duration. Three (9.7%) patients had a history of trauma, and the rest had insidious onset. The average spinal canal ventral-occupying ratio was 74.90 ± 15.16%. The most prominent radiographic feature was the calcification of the nucleus pulposus in the intervertebral disc and the calcified lesion contiguous with the disc space protruding into the spinal canal. Three main imaging forms of CTDH were found: calcium-ringed lesion (5), heterogeneous calcification lesion (19), and homogeneous calcification lesion (7). The radiographic manifestations, intraoperative findings, and postoperative pathologies of the three subtypes were different. The calcium-ringed lesion type was younger and had a shorter preoperative duration and significantly lower mJOA score. A special case was observed conservatively for five years, which suggested that a heterogeneous lesion could progress to a homogeneous lesion. Adult CTDH is a special thoracic disc disease with insidious onset, a long course, and a high spinal canal-occupying ratio. Calcium deposits in the spinal canal originate from the nucleus pulposus. The intraoperative findings and postoperative pathology of subtypes are different, which might indicate different pathological mechanisms.

Effectiveness and postoperative rehabilitation of one-stage combined anterior-posterior surgery for severe thoracolumbar fractures with spinal cord injury

BACKGROUNDThoracolumbar fractures are generally combined with spinal cord injury to varying degrees, which may cause deterioration of the patients' condition and increase the difficulty of clinical treatment. At present, anterior or combined anterior-posterior surgery is preferred for severe thoracolumbar fractures.AIMTo investigate the effectiveness and postoperative rehabilitation of one-stage combined anterior-posterior surgery for severe thoracolumbar fractures with spinal cord injury.METHODSOne-hundred-and-twenty patients who received surgery for severe thoracolumbar fractures with spinal cord injury at our hospital from February 2018 to February 2020 were randomly enrolled. They were randomly divided into group 1 (one-stage combined anterior-posterior surgery, n = 60) and group 2 (one-stage anterior-approach surgery, n = 60). Treatment efficacy was compared between the two groups.RESULTSBlood loss was greater and the operation time was longer in group 1 than in group 2, and the differences were statistically significant (P < 0.05). Incision length, intraoperative X-rays, and length of hospital stay were not significantly different between the two groups (P > 0.05). Preoperative function of the affected vertebrae was not significantly different between the two groups (P > 0.05). In each group, the patients showed significant improvement after surgery. The anterior vertebral height ratio and the posterior vertebral height ratio in group 1 after surgery were significantly higher than those in group 2. The Cobb angle after surgery was significantly lower in group 1 than in group 2 (P < 0.05). The canal-occupying ratio of the affected vertebrae was not significantly different between the two groups (P > 0.05). Before surgery, there was no significant difference in the quality of life scores between the two groups (P > 0.05). The above indicators were significantly improved after surgery compared with before surgery in each group. In addition, these indicators were markedly better in group 1 than in group 2 after surgery (P < 0.05 for each).CONCLUSIONOne-stage combined anterior-posterior surgery effectively improves the function of the affected vertebrae and the life quality of patients with severe thoracolumbar fractures and spinal cord injury. This surgical approach is worthy of popularization in clinical use.

Risk factor analysis of surgery-related complications in primary cervical spine surgery for degenerative diseases using a surgeon-maintained database.

This study, using a surgeon-maintained database, aimed to explore the risk factors for surgery-related complications in patients undergoing primary cervical spine surgery for degenerative diseases. We studied 5,015 patients with degenerative cervical diseases who underwent primary cervical spine surgery from 2012 to 2018. We investigated the effects of diseases, surgical procedures, and patient demographics on surgery-related complications. As subcategories, the presence of cervical kyphosis ≥ 10°, the presence of ossification of the posterior longitudinal ligament (OPLL) with a canal-occupying ratio ≥ 50%, and foraminotomy were selected. The surgery-related complications examined were postoperative upper limb palsy (ULP) with a manual muscle test (MMT) grade of 0 to 2 or a reduction of two grade or more in the MMT, neurological deficit except ULP, dural tear, dural leakage, surgical-site infection (SSI), and postoperative haematoma. Multivariate logistic regression analysis was performed. The significant risk factors (p < 0.050) for ULP were OPLL (odds ratio (OR) 1.88, 95% confidence interval (CI) 1.29 to 2.75), foraminotomy (OR 5.38, 95% CI 3.28 to 8.82), old age (per ten years, OR 1.18, 95% CI 1.03 to 1.36), anterior spinal fusion (OR 2.85, 95% CI 1.53 to 5.34), and the number of operated levels (OR 1.25, 95% CI 1.11 to 1.40). OPLL was also a risk factor for neurological deficit except ULP (OR 5.84, 95% CI 2.80 to 12.8), dural tear (OR 1.94, 95% CI 1.11 to 3.39), and dural leakage (OR 3.15, 95% CI 1.48 to 6.68). Among OPLL patients, dural tear and dural leakage were frequently observed in those with a canal-occupying ratio ≥ 50%. Cervical rheumatoid arthritis (RA) was a risk factor for SSI (OR 10.1, 95% CI 2.66 to 38.4). The high risk of ULP, neurological deficit except ULP, dural tear, and dural leak should be acknowledged by clinicians and OPLL patients, especially in those patients with a canal-occupying ratio ≥ 50%. Foraminotomy and RA were dominant risk factors for ULP and SSI, respectively. An awareness of these risks may help surgeons to avoid surgery-related complications in these conditions. Cite this article: Bone Joint J 2021;103-B(1):157-163.

What Are the Important Predictors of Postoperative Functional Recovery in Patients With Cervical OPLL? Results of a Multivariate Analysis

Study Design:A retrospective cohort study.Objective:The objective of this study was to identify important predictors of poor functional recovery in patients undergoing surgery for cervical ossification of the posterior longitudinal ligament (OPLL).Methods:This was a retrospective cohort study of 142 OPLL patients with laminoplasty; 135 had complete radiographical data and were followed up for ≥2 years. The following OPLL characteristics were compared between patients with “good” and “poor” outcomes (Japanese Orthopedic Association [JOA] recovery rate ≥50% and <50%, respectively): number of ossified levels, OPLL classification, ossification shape, K-line, canal-occupying ratio, and increased magnetic resonance imaging (MRI) signal intensity. Predictors of functional recovery were identified.Results:Pre- and postoperative (2 years following surgery) JOA scores were 10.6 ± 2.9 and 14.1 ± 2.2, respectively, indicating significant improvement following laminoplasty (P < .001). The average JOA recovery rate was 53.4% ± 34.7%, with 81 (60.0%) and 54 (40.0%) patients in the better and poorer neurological outcome groups, respectively. The canal occupation ratio of OPLL ≤60%/>60% were 117 (86.7%) and 18 (13.3%) patients, respectively. In the stepwise logistic regression analysis, an occupation ratio greater than 60% was identified as a significant factor for poor postoperative neurological outcome (relative risk, 4.82; 95% confidential interval, 1.61-14.46, P = .005).Conclusions:This multivariate analysis demonstrated a large size OPLL (occupying ratio >60%) was associated with a risk of poor neurological recovery roughly 5 times greater, and therefore other types of surgery are recommended in cases with such a ratio.

A novel anterior decompression technique (vertebral body sliding osteotomy) for ossification of posterior longitudinal ligament of the cervical spine

Background ContextConventional anterior decompression surgery for cervical myelopathy, including anterior corpectomy and fusion, is technically demanding and is known to be associated with a higher incidence of surgery-related complications, including cerebrospinal fluid (CSF) leakage, neurologic deterioration, and graft failure compared with posterior surgery. PurposeWe introduce a novel anterior decompression technique (vertebral body sliding osteotomy [VBSO]) for cervical myelopathy caused by ossification of posterior longitudinal ligament (OPLL) and evaluate the efficacy and safety of this procedure. Study DesignThis is a case series for novel surgical technique. Patient SampleFourteen patients (M:F=11:3, mean age 56.9±10) with cervical myelopathy caused by OPLL who underwent VBSO by a single surgeon were included. Outcome MeasuresThe surgical outcome was evaluated according to the Japanese Orthopaedic Association score for cervical myelopathy (C-JOA score), and the recovery rate of the C-JOA score was calculated. Patients were also evaluated radiographically with plain and dynamic cervical spine radiographs and pre- and postoperative computed tomography images. MethodsFourteen patients were followed up for more than 24 months, and operation time, estimated blood loss, neurologic outcomes, and surgery-related complications were investigated. Radiological measurements were also performed to analyze the following parameters: (1) canal-occupying ratio and postoperative canal widening, and (2) pre- and postoperative sagittal alignment. ResultsThe mean recovery rate of C-JOA score at the final follow-up was 68.65±17.8%. There were no perioperative complications, including neurologic deterioration, vertebral artery injury, esophageal injury, graft dislodgement, and CSF leaks, after surgery except for pseudarthrosis in one case. An average spinal canal compromised ratio by OPLL decreased from 61.5±8.1% preoperatively to 16.5±11.2% postoperatively. An average postoperative canal widening was 5.15±1.39 mm, and improvement of cervical alignment was observed in all patients, with average recovery angle of 7.3±6.1° postoperatively. ConclusionsThe VBSO allows sufficient decompression of spinal cord and provides excellent neurologic outcomes. Because surgeons do not need to manipulate the OPLL mass directly, this technique could significantly decrease surgery-related complications. Furthermore, as VBSO is based on the multilevel discectomy and fusion technique, it would be more helpful to restore a physiological lordosis.

Magnetic resonance imaging vertebral canal and body ratios in Doberman Pinschers with and without disk-associated cervical spondylomyelopathy and clinically normal English Foxhounds

To determine magnetic resonance imaging (MRI) vertebral ratio values representing vertebral canal height, vertebral canal shape, and vertebral body shape in Doberman Pinschers with and without disk-associated cervical spondylomyelopathy (DACSM) and clinically normal English Foxhounds. Doberman Pinschers with (n = 18) and without (20) DACSM and clinically normal English Foxhounds (18). All dogs underwent low-field MRI of the cervical vertebral column. From 5 specific measurements made at C3 through C7, 4 linear vertebral ratios were calculated and assessed for correlation: vertebral canal height-to-body height ratio (CBHR), vertebral canal height-to-body length ratio (CBLR), caudal canal height-to-cranial canal height ratio (CCHR), and vertebral body length-to-height ratio (BLHR). The CBHR and CBLR described vertebral canal height, CCHR described vertebral canal shape, and BLHR described vertebral body shape. A midvertebral canal-occupying ratio (mVCOR) for the spinal cord was calculated at C5. RESULTS; Compared with both groups of unaffected dogs, CBHR, CBLR, and BLHR for Doberman Pinschers with DACSM were significantly smaller. The C7 CCHR was significantly larger in DACSM-affected Doberman Pinschers, compared with clinically normal English Foxhounds. Ratios did not differ significantly between unaffected Doberman Pinschers and clinically normal English Foxhounds. Correlation coefficients between CBHR, CBLR, and mVCOR were low and not significant. Doberman Pinschers with DACSM had significantly smaller vertebral canal heights and more square-shaped vertebral bodies, compared with unaffected Doberman Pinschers, combined with a funnel-shaped vertebral canal at C7. Breed-specific differences were not evident. Linear MRI vertebral canal-to-body ratios do not appear to predict relative vertebral canal stenosis.