Torg-Pavlov Ratio Research Articles

The Torg-Pavlov ratio for the prediction of acute spinal cord injury after a minor trauma to the cervical spine

Background contextAcute cervical spinal cord injury (SCI) has been observed in some patients after a minor trauma to the cervical spine. The discrepancy between the severity of the trauma and the clinical symptoms has been attributed to spinal canal stenosis. However, to date, there is no universally established radiological parameter for identifying critical spinal stenosis in these patients. The spinal canal–to–vertebral body ratio (Torg-Pavlov ratio) has been proposed for assessing developmental spinal canal stenosis. The relevance of the Torg-Pavlov ratio for predicting the occurrence and severity of acute cervical SCI after a minor trauma to the cervical spine has not yet been established. PurposeTo investigate the Torg-Pavlov ratio values of the cervical spine in patients suffering from acute cervical SCI after a minor trauma to the cervical spine and the use of the Torg-Pavlov ratio for identifying patients at risk of cervical SCI and predicting the severity and course of symptoms. Study design/settingRetrospective radiological study of consecutive patients. Patient sampleForty-five patients suffering from acute cervical SCI and 68 patients showing no neurologic symptoms after a minor trauma to the cervical spine. Outcome measuresMidvertebral sagittal cervical spinal canal diameter and the sagittal vertebral body diameter. Calculation of the Torg-Pavlov ratio values. MethodsConventional lateral radiographs of the cervical spine (C3–C7) were analyzed to determine the Torg-Pavlov ratio values. Receiver operating characteristic curves were calculated for evaluating the classification accuracy of the Torg-Pavlov ratio for predicting SCI. ResultsThe Torg-Pavlov ratio values in the SCI group were significantly (p<.04) smaller compared with that in the control group. A Torg-Pavlov ratio cutoff value of 0.7 yielded the greatest positive likelihood ratio for predicting the occurrence of SCI. However, there were no significant differences in the Torg-Pavlov ratio values between the different American Spinal Injury Association Impairment Score groups and between patients with complete, partial, and no recovery of symptoms. ConclusionsDevelopmental cervical spinal canal stenosis assessed by the Torg-Pavlov ratio was characteristic for patients suffering from acute cervical SCI after a minor trauma to the cervical spine. Patients at risk of SCI after a minor trauma to the cervical spine can be identified by applying a Torg-Pavlov ratio cutoff value of 0.7. Other factors in addition to the spinal canal–to–vertebral body ratio affect the severity and course of symptoms as a result of cervical SCI.

Predictive factors of cervical spondylotic myelopathy in patients with lumbar spinal stenosis

To analyze cervical spondylotic myelopathy (CSM) predictive factors in patients with lumbar spinal stenosis (LSS). Two hundred thirty-seven patients who visited for low back pain, lower limb pain and/or lower limb numbness and who were diagnosed with LSS were enrolled in this study. The ratio of males to females was 117-120, and the mean age was 68.8 years (range 45-87 years). LSS and CSM were diagnosed by characteristic symptoms, physical findings and MRI. We examined gender, age, Torg-Pavlov ratio (TPR), spondylolisthesis or spondylosis, LSS symptom types and number of stenosis segments with LSS to clarify predictive factors for CSM. There were 21 (8.86%) patients with coexistent CSM among 237 LSS patients. CSM morbidity was significantly more common among males compared with females. TPR was 0.71 ± 0.09 in the CSM patients and 0.81 ± 0.10 in the non-CSM patients. TPR of the CSM patients was significantly smaller than that of the non-CSM patients. We analyzed to determine the predictive factors of CSM and TPR was identified. The predictive value of TPR for CSM was 0.78. Torg-Pavlov ratio was the most important predictive factor of CSM in patients with LSS.

Asymptomatic Cervical Cord Compression in Lumbar Spinal Stenosis Patients

A retrospective study. To analyze incidence of asymptomatic cervical cord compression and related factors in lumbar stenosis patients. Neural compression resulted from degenerative disc is not unusual in the asymptomatic cervical spine. However, its incidence and clinically related factors in lumbar stenosis patients have not been studied. We analyzed lumbar stenosis index (LSI), cervical cord compression index (CCI), and Torg-Pavlov ratio of whole spine magnetic resonance images of 93 lumbar stenosis patients. We compared lumbar stenosis involving a single segment versus multiple segments in the cases with the LSI of double-level or more, patients in 60s versus in 70s, and male versus female for the above variables. Of total 93 cases, 71 cases did not demonstrate cervical cord compression, but moderate or severe cervical cord compression was observed in 22 cases (23.7%). The multiple segment lumbar stenosis group, the 70s group, and male group had statistically significant higher CCI. The correlation coefficient between the CCI and the LSI indicated a strong positive linear relationship with 0.54 (P = 0). Moderate or severe cervical cord compression was observed in 24% of lumbar stenosis patients. Asymptomatic cervical cord compression is more likely to be developed in lumbar stenosis patients who are aged, male, and involving multiple segments. These factors should be considered for management of lumbar stenosis patients.

Intramedullary high signal intensity and neurological status as prognostic factors in cervical spondylotic myelopathy

The neurological outcome of cervical spondylotic myelopathy (CSM) may depend on multiple factors, including age, symptom duration, cord compression ratio, cervical curvature, canal stenosis, and factors related to magnetic resonance (MR) signal intensity (SI). Each factor may act independently or interactively with others. To clarify the factors in prognosis, we prospectively analyzed the outcomes of patients with myelopathy caused by soft disc herniation in correlation with magnetic resonance imaging (MRI) findings and other clinical parameters. From June 2006 to July 2009, we performed surgical operations in 137 patients with CSM. Of these patients, 70 (51.1%), including 45 men and 25 women with ventral cord compression at one or two levels, underwent anterior cervical discectomy and fusion. The mean duration of follow-up was 32.7 months. We surveyed the cervical curvature index (CCI), canal stenosis (Torg-Pavlov ratio), cord compression ratio, the length of SI change on T2WI, and clinical outcome using the Japanese Orthopedic Association (JOA) score for cervical myelopathy. The MRI SI was evaluated by grade: grade 0, no change in signal intensity; grade 1, light signal change; and grade 2, bright signal change on the T2WI. Multifactorial effects were identified by regression analysis. The mean preoperative and postoperative JOA scores were 10.5 ± 2.9 and 14.9 ± 2.1, respectively (p < 0.05). The mean recovery rate based on the JOA score was 70.0 ± 20.1%. The respective preoperative JOA scores and recovery ratios(%) were 11.6 ± 2.3 and 81.5 ± 17.0% in 20 patients with SI grade 0; 10.8 ± 2.3 and 70.1 ± 17.3% in 25 patients with grade 1; and 9.2 ± 3.6 and 60.7 ± 20.9% in 25 patients with grade 2, respectively. Post-surgical neurological outcome showed no significant relationship to age, symptom duration, cervical alignment, stenosis, or cord compression. Among the variables tested, preoperative neurological status and intramedullary signal intensity were significantly related to neurological outcome. The better the preoperative neurological status was, the better the post-operative neurological outcome. The SI grade on the preoperative T2WI was negatively related to neurological outcome. Hence, the severity of SI change and preoperative neurological status emerged as significant prognostic factors in post-operative CSM.

Reference Values for Radiologic Evaluation of Cervical Canal, Vertebral Body, and Torg-Pavlov Ratio

The present study was aimed to analyze the mean values of the cervical dimensions on plain lateral radiographs. The sagittal canal diameter (SCD) and vertebral body diameter (VBD) were measured using an electronic digital caliper from the levels of C2 to C7 in 424 (226 women, 198 men) radiographs of healthy people aged 20 to 50 years. After these measurements, Torg-Pavlov ratio (the ratio between the SCD and the VBD) was estimated. The mean SCD was found between 19.8±1.2 mm and 18.8±0.8 mm from the levels of C2 to C7 in women whereas same dimension was between 20.4±1.1 mm and 19.5±0.9 mm in men. Additionally, the mean values of the VBD were found between 17.1±0.9 mm and 18.4±0.7 mm in women and between 18.0±1.1 mm and 19.4±1.0 mm in men from the levels of C2 to C7. The Torg-Pavlov ratio was observed 1.1 to 0.9 in women and 1.0 to 0.9 in men.