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PURPOSE: Intervertebral vacuum phenomenon (IVP) and paraspinal muscular atrophy are age-related changes in the lumbar spine. The relationship between both parameters has not been investigated. We aimed to analyze the correlation between IVP and paraspinal muscular atrophy in addition to describing the lumbar vacuum severity (LVS) scale, a new parameter to estimate lumbar degeneration. METHODS: We analyzed patients undergoing spine surgery between 2014 and 2016. IVP severity was assessed utilizing CT scans. The combination of vacuum severity on each lumbar level was used to define the LVS scale, which was classified into mild, moderate and severe. MRIs were used to evaluate paraspinal muscular fatty infiltration of the multifidus and erector spinae. The association of fatty infiltration with the severity of IVP at each lumbar level was assessed with a univariable and multivariable ordinal regression model. RESULTS: Two hundred and sixty-seven patients were included in our study (128 females and 139 males) with a mean age of 62.6 years (55.1-71.2). Multivariate analysis adjusted for age, BMI and sex showed positive correlations between LVS-scale severity and fatty infiltration in the multifidus and erector spinae, whereas no correlation was observed in the psoas muscle. CONCLUSION: IVP severity is positively correlated with paraspinal muscular fatty infiltration. This correlation was stronger for the multifidus than the erector spinae. No correlations were observed in the psoas muscle. The lumbar vacuum severity scale was significantly correlated with advanced disc degeneration with vacuum phenomenon.
Assuntos
Degeneração do Disco Intervertebral , Músculos Paraespinais , Masculino , Feminino , Humanos , Pessoa de Meia-Idade , Músculos Paraespinais/diagnóstico por imagem , Músculos Paraespinais/patologia , Vácuo , Atrofia Muscular/diagnóstico por imagem , Atrofia Muscular/etiologia , Atrofia Muscular/patologia , Degeneração do Disco Intervertebral/diagnóstico por imagem , Degeneração do Disco Intervertebral/cirurgia , Degeneração do Disco Intervertebral/patologia , Imageamento por Ressonância Magnética , Vértebras Lombares/diagnóstico por imagem , Vértebras Lombares/cirurgia , Vértebras Lombares/patologiaRESUMO
OBJECTIVE: There are limited data about the influence of the lumbar paraspinal muscles on the maintenance of sagittal alignment after pedicle subtraction osteotomy (PSO) and the risk factors for sagittal realignment failure. The authors aimed to investigate the influence of preoperative lumbar paraspinal muscle quality on the postoperative maintenance of sagittal alignment after lumbar PSO. METHODS: Patients who underwent lumbar PSO with preoperative lumbar MRI and pre- and postoperative whole-spine radiography in the standing position were included. Spinopelvic measurements included pelvic incidence, sacral slope, pelvic tilt, L1-S1 lordosis, T4-12 thoracic kyphosis, spinosacral angle, C7-S1 sagittal vertical axis (SVA), T1 pelvic angle, and mismatch between pelvic incidence and L1-S1 lordosis. Validated custom software was used to calculate the percent fat infiltration (FI) of the psoas major, as well as the erector spinae and multifidus (MF). A multivariable linear mixed model was applied to further examine the association between MF FI and the postoperative progression of SVA over time, accounting for repeated measures over time that were adjusted for age, sex, BMI, and length of follow-up. RESULTS: Seventy-seven patients were recruited. The authors' results demonstrated significant correlations between MF FI and the maintenance of corrected sagittal alignment after PSO. After adjustment for the aforementioned parameters, the model showed that the MF FI was significantly associated with the postoperative progression of positive SVA over time. A 1% increase from the preoperatively assessed total MF FI was correlated with an increase of 0.92 mm in SVA postoperatively (95% CI 0.42-1.41, p < 0.0001). CONCLUSIONS: This study included a large patient cohort with midterm follow-up after PSO and emphasized the importance of the lumbar paraspinal muscles in the maintenance of sagittal alignment correction. Surgeons should assess the quality of the MF preoperatively in patients undergoing PSO to identify patients with severe FI, as they may be at higher risk for sagittal decompensation.
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Vértebras Lombares , Osteotomia , Músculos Paraespinais , Humanos , Masculino , Feminino , Músculos Paraespinais/diagnóstico por imagem , Osteotomia/métodos , Vértebras Lombares/cirurgia , Vértebras Lombares/diagnóstico por imagem , Pessoa de Meia-Idade , Lordose/cirurgia , Lordose/diagnóstico por imagem , Idoso , Cifose/cirurgia , Cifose/diagnóstico por imagem , Adulto , Imageamento por Ressonância Magnética , Fusão Vertebral/métodosRESUMO
OBJECTIVE: The aim of this study was to investigate the influence of preoperatively assessed paraspinal muscle parameters on postoperative patient-reported outcomes and maintenance of cervical sagittal alignment after anterior cervical discectomy and fusion (ACDF). METHODS: Patients with preoperative and postoperative standing cervical spine lateral radiographs and preoperative cervical MRI who underwent an ACDF between 2015 and 2018 were reviewed. Muscles from C3 to C7 were segmented into 4 functional groups: anterior, posteromedial, posterolateral, and sternocleidomastoid. The functional cross-sectional area and also the percent fat infiltration (FI) were calculated for all groups. Radiographic alignment parameters collected preoperatively and postoperatively included C2-7 lordosis and C2-7 sagittal vertical axis (SVA). Neck Disability Index (NDI) scores were recorded preoperatively and at 2 and 4-6 months postoperatively. To investigate the relationship between muscle parameters and postoperative changes in sagittal alignment, multivariable linear mixed models were used. Multivariable linear regression models were used to analyze the correlations between the changes in NDI scores and the muscles' FI. RESULTS: A total of 168 patients with NDI and 157 patients with sagittal alignment measurements with a median follow-up of 364 days were reviewed. The mixed models showed that a greater functional cross-sectional area of the posterolateral muscle group at each subaxial level and less FI at C4-6 were significantly associated with less progression of C2-7 SVA over time. Moreover, there was a significant correlation between greater FI of the posteromedial muscle group measured at the C7 level and less NDI improvement at 4-6 months after ACDF. CONCLUSIONS: The findings highlight the importance of preoperative assessment of the cervical paraspinal muscle morphology as a predictor for patient-reported outcomes and maintenance of C2-7 SVA after ACDF.
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Vértebras Cervicais , Discotomia , Músculos Paraespinais , Medidas de Resultados Relatados pelo Paciente , Fusão Vertebral , Humanos , Discotomia/métodos , Feminino , Fusão Vertebral/métodos , Vértebras Cervicais/cirurgia , Vértebras Cervicais/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Músculos Paraespinais/diagnóstico por imagem , Adulto , Lordose/cirurgia , Lordose/diagnóstico por imagem , Idoso , Resultado do Tratamento , Estudos Retrospectivos , Imageamento por Ressonância Magnética , Período Pós-OperatórioRESUMO
OBJECTIVE: The cervical multifidus and rotatores muscles are innervated by the posterior rami of the spinal nerves of the corresponding level, and it has been hypothesized that cervical foraminal stenosis (CFS) affecting the spinal nerves results in changes in these muscles. The purpose of this study was to evaluate the relationship between the severity of CFS and fat infiltration (FI) of the multifidus and rotatores muscles. METHODS: Patients who received preoperative cervical MRI, underwent anterior cervical decompression and fusion between 2015 and 2018, and met inclusion and exclusion criteria were included. Multifidus and rotatores muscles were segmented bilaterally from C3 to C7, and the percent FI was measured using custom-written MATLAB software. The severity of the CFS was assessed by the Kim classification. Multivariable linear mixed models were conducted and adjusted for age, sex, BMI, and repeated measures. RESULTS: In total, 149 patients were included. Linear mixed modeling results showed that a more severe CFS at C3-4 was correlated with a greater FI of the multifidus and rotatores muscles at C4 (estimate 0.034, 95% CI 0.003-0.064; p = 0.031), a more severe CFS at C4-5 was correlated with a greater FI of the multifidus and rotatores muscles at C5 (estimate 0.037, 95% CI 0.015-0.057; p < 0.001), a more severe CFS at C5-6 was correlated with a greater FI of the multifidus and rotatores muscles at C6 (estimate 0.041, 95% CI 0.019-0.062; p < 0.001) and C7 (estimate 0.035, 95% CI 0.012-0.058; p = 0.003), and a more severe CFS at C6-7 was correlated with a greater FI of the multifidus and rotatores muscles at C7 (estimate 0.049, 95% CI 0.027-0.071; p < 0.001). CONCLUSIONS: These results demonstrated level- and side-specific correlations between the FI of the multifidus and rotatores muscles and severity of CFS. Given the segmental innervation of the multifidus and rotatores muscles, the authors hypothesize that the observed increased FI could be reflective of changes due to muscle denervation from CFS.
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Discotomia , Músculos Paraespinais , Humanos , Músculos Paraespinais/diagnóstico por imagem , Músculos Paraespinais/cirurgia , Constrição Patológica , SoftwareRESUMO
STUDY DESIGN: Retrospective review of prospectively collected data. OBJECTIVE: The authors aim to investigate the association between muscle functional group characteristics and sagittal alignment parameters in patients undergoing anterior cervical discectomy and fusion. SUMMARY OF BACKGROUND DATA: The relationship between the morphology of cervical paraspinal muscles and sagittal alignment is not well understood. MATERIALS AND METHODS: Patients with preoperative cervical magnetic resonance imaging and cervical spine lateral radiographs in standing position who underwent anterior cervical discectomy and fusion between 2015 and 2018 were reviewed. Radiographic alignment parameters included C2 to 7 lordosis, C2 to 7 sagittal vertical axis (SVA), C2 slope, neck tilt, T1 slope, and thoracic inlet angle. Muscles from C3 to C7 were categorized into four functional groups: sternocleidomastoid group, anterior group, posteromedial group, and posterolateral group (PL). A custom-written Matlab software was used to assess the functional cross-sectional area (fCSA) and percent fat infiltration (FI) for all groups. Multivariable linear regression analyses were conducted and adjusted for age, sex, and body mass index. RESULTS: A total of 172 patients were included. Regression analyses demonstrated that a greater C2 to 7 SVA was significantly associated with a greater FI of the anterior group from C3 to C5 and with a higher fCSA of the PL group at C3 to C4, and C6 to 7. A larger C2 slope was significantly correlated with a greater FI of the anterior group at C3 to C4 and a higher fCSA of the PL group from C3 to C5. CONCLUSION: This work proposes new insights into the complex interaction between sagittal alignment and cervical paraspinal muscles by emphasizing the importance of these muscles in sagittal alignment. The authors hypothesize that with cervical degeneration, the stabilizing function of the anterior muscles decreases, which may result in an increase in the compensatory mechanism of the PL muscles. Consequently, there may be a corresponding increase in the C2 to C7 SVA and a larger C2 slope.
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Vértebras Cervicais , Lordose , Humanos , Vértebras Cervicais/diagnóstico por imagem , Vértebras Cervicais/cirurgia , Músculos Paraespinais/diagnóstico por imagem , Pescoço , Lordose/diagnóstico por imagem , Lordose/cirurgia , Músculos do Pescoço , Estudos RetrospectivosRESUMO
STUDY DESIGN: Retrospective study. OBJECTIVE: The aim of this study was to evaluate the association between severity and level of cervical central stenosis (CCS) and the fat infiltration (FI) of the cervical multifidus/rotatores (MR) at each subaxial levels. SUMMARY OF BACKGROUND DATA: The relationship between cervical musculature morphology and the severity of CCS is poorly understood. METHODS: Patients with preoperative cervical magnetic resonance imaging (MRI) who underwent anterior cervical discectomy and fusion (ACDF) were reviewed. The cervical MR were segmented from C3 to C7 and the percent FI was measured using a custom-written Matlab software. The severity of the CCS at each subaxial level was assessed using a previously published classification. Grade 3, representing a loss of cerebrospinal fluid space and deformation of the spinal cord > 25%, was set as the reference and compared to the other gradings. Multivariable linear regression analyses were conducted and adjusted for age, sex, and body mass index. RESULTS: 156 consecutive patients were recruited. A spinal cord compression at a certain level was significantly associated with a greater FI of the MR below that level. After adjustment for the above-mentioned confounders, our results showed that spinal cord compression at C3/4 and C4/5 was significantly associated with greater FI of the MR from C3 to C6 and C5 to C7, respectively. A spinal cord compression at C5/6 or C6/7 was significantly associated with greater FI of the MR at C7. CONCLUSION: Our results demonstrated significant correlations between the severity of CCS and a greater FI of the MR. Moreover, significant level-specific correlations were found. A significant increase in FI of the MR at the levels below the stenosis was observed in patients presenting with spinal cord compression. Given the segmental innervation of the MR, the increased FI might be attributed to neurogenic atrophy. LEVEL OF EVIDENCE: 3.
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Introducción: La cirugía mínimamente invasiva de columna se ha vuelto cada vez más popular en los últimos años. Se han desarrollado técnicas nuevas y menos invasivas que se han convertido en procedimientos de elección para determinadas enfermedades. El tamaño del corredor aorto-psoas es un factor determinante al elegir la técnica oblicua de fusión intersomática. Objetivos: Describir las modificaciones en el tamaño del corredor aorto-psoas en decúbito lateral derecho y decúbito supino mediante resonancia magnética y su asociación con el índice de masa corporal. materiales y métodos: Se realizó una resonancia magnética de los espacios discales de L1-L2 a L4-L5 a 13 voluntarios en decúbito supino y decúbito lateral derecho. Se midió el corredor y se comparó el tamaño en cada nivel. Resultados: El tamaño del corredor aorto-psoas y de la distancia arteria-disco tuvo un aumento estadísticamente significativo al posicionar al paciente en decúbito lateral derecho. Conclusiones: La resonancia magnética es de suma importancia en la planificación prequirúrgica, pues deja en evidencia la movilidad de las estructuras abdominales. Se producen cambios significativos en el corredor aorto-psoas y la distancia arteria-disco al ubicar al paciente en decúbito lateral derecho. Sin embargo, estos cambios no tienen una relación significativa con el índice de masa corporal. Nivel de Evidencia: IV
Introduction: Minimally invasive spine surgery (MISS) has gained popularity in recent years. New and less invasive techniques have emerged as the preferred procedures for certain pathologies. The size of the aorta-psoas corridor is decisive when choosing the oblique interbody fusion technique. Objectives: To describe the changes in the size of the aorta-psoas corridor in the right lateral decubitus and supine decubitus positions by magnetic resonance imaging and their association with body mass index. materials and methods: 13 volunteers underwent MRI of the disc spaces from L1-L2 to L4-L5 in the supine and right lateral decubitus positions. The corridor was measured, and the sizes at each level were compared. Results: A statistically significant increase in the size of the aorta-psoas corridor and the artery-disc distance was obtained when positioning the patient in the right lateral decubitus position. However, these have no significant relationship with BMI. Conclusions: The use of MRI in pre-surgical planning is extremely important. This study reveals the mobility of the abdominal structures. We can conclude that, as stated in the objective of the study, significant changes occur in the aorta-psoas corridor and the artery-disc distance when the patient is positioned in the right lateral decubitus position. Level of Evidence: IV