Benjamin Blondel

Radiographical spinopelvic parameters and disability in the setting of adult spinal deformity: a prospective multicenter analysis.

Study Design. Prospective multicenter study evaluating operative (OP) versus nonoperative (NONOP) treatment for adult spinal deformity (ASD). Objective. Evaluate correlations between spinopelvic parameters and health-related quality of life (HRQOL) scores in patients with ASD. Summary of Background Data. Sagittal spinal deformity is commonly defined by an increased sagittal vertical axis (SVA); however, SVA alone may underestimate the severity of the deformity. Spinopelvic parameters provide a more complete assessment of the sagittal plane but only limited data are available that correlate spinopelvic parameters with disability. Methods. Baseline demographic, radiographical, and HRQOL data were obtained for all patients enrolled in a multicenter consecutive database. Inclusion criteria were: age more than 18 years and radiographical diagnosis of ASD. Radiographical evaluation was conducted on the frontal and lateral planes and HRQOL questionnaires (Oswestry Disability Index [ODI], Scoliosis Research Society-22r and Short Form [SF]-12) were completed. Radiographical parameters demonstrating highest correlation with HRQOL values were evaluated to determine thresholds predictive of ODI more than 40. Results. Four hundred ninety-two consecutive patients with ASD (mean age, 51.9 yr) were enrolled. Patients from the OP group (n = 178) were older (55 vs. 50.1 yr, P < 0.05), had greater SVA (5.5 vs. 1.7 cm, P < 0.05), greater pelvic tilt (PT; 22° vs. 11°, P < 0.05), and greater pelvic incidence/lumbar lordosis PI/LL mismatch (PI-LL; 12.2 vs. 4.3; P < 0.05) than NONOP group (n = 314). OP group demonstrated greater disability on all HRQOL measures compared with NONOP group (ODI = 41.4 vs. 23.9, P < 0.05; Scoliosis Research Society score total = 2.9 vs. 3.5, P < 0.05). Pearson analysis demonstrated that among all parameters, PT, SVA, and PI-LL correlated most strongly with disability for both OP and NONOP groups (P < 0.001). Linear regression models demonstrated threshold radiographical spinopelvic parameters for ODI more than 40 to be: PT 22° or more (r = 0.38), SVA 47 mm or more (r = 0.47), PI − LL 11° or more (r = 0.45). Conclusion. ASD is a disabling condition. Prospective analysis of consecutively enrolled patients with ASD demonstrated that PT and PI-LL combined with SVA can predict patient disability and provide a guide for patient assessment for appropriate therapeutic decision making. Threshold values for severe disability (ODI > 40) included: PT 22° or more, SVA 47 mm or more, and PI − LL 11° or more.

Cervical spine alignment, sagittal deformity, and clinical implications

This paper is a narrative review of normal cervical alignment, methods for quantifying alignment, and how alignment is associated with cervical deformity, myelopathy, and adjacent-segment disease (ASD), with discussions of health-related quality of life (HRQOL). Popular methods currently used to quantify cervical alignment are discussed including cervical lordosis, sagittal vertical axis, and horizontal gaze with the chin-brow to vertical angle. Cervical deformity is examined in detail as deformities localized to the cervical spine affect, and are affected by, other parameters of the spine in preserving global sagittal alignment. An evolving trend is defining cervical sagittal alignment. Evidence from a few recent studies suggests correlations between radiographic parameters in the cervical spine and HRQOL. Analysis of the cervical regional alignment with respect to overall spinal pelvic alignment is critical. The article details mechanisms by which cervical kyphotic deformity potentially leads to ASD and discusses previous studies that suggest how postoperative sagittal malalignment may promote ASD. Further clinical studies are needed to explore the relationship of cervical malalignment and the development of ASD. Sagittal alignment of the cervical spine may play a substantial role in the development of cervical myelopathy as cervical deformity can lead to spinal cord compression and cord tension. Surgical correction of cervical myelopathy should always take into consideration cervical sagittal alignment, as decompression alone may not decrease cord tension induced by kyphosis. Awareness of the development of postlaminectomy kyphosis is critical as it relates to cervical myelopathy. The future direction of cervical deformity correction should include a comprehensive approach in assessing global cervicalpelvic relationships. Just as understanding pelvic incidence as it relates to lumbar lordosis was crucial in building our knowledge of thoracolumbar deformities, T-1 incidence and cervical sagittal balance can further our understanding of cervical deformities. Other important parameters that account for the cervical-pelvic relationship are surveyed in detail, and it is recognized that all such parameters need to be validated in studies that correlate HRQOL outcomes following cervical deformity correction.

Cervical radiographical alignment: comprehensive assessment techniques and potential importance in cervical myelopathy.

Study Design. Narrative review. Objective. To provide a comprehensive narrative review of cervical alignment parameters, the methods for quantifying cervical alignment, normal cervical alignment values, and how alignment is associated with cervical deformity and myelopathy with discussions of health-related quality of life. Summary of Background Data. Indications for surgery to correct cervical alignment are not well-defined and there is no set standard to address the amount of correction to be achieved. In addition, classifications of cervical deformity have yet to be fully established and treatment options defined and clarified. Methods. A survey of the cervical spine literature was conducted. Results. New normative cervical alignment values from an asymptomatic volunteer population are introduced, updated methods for quantifying cervical alignment are discussed, and describing the relationship between cervical alignment, disability, and myelopathy are outlined. Specifically, methods used to quantify cervical alignment include cervical lordosis, cervical sagittal vertical axis, and horizontal gaze with the chin-brow vertical angle. Updated methods include T1 slope. Evidence from a few recent studies suggests correlations between radiographical parameters in the cervical spine and health-related quality of life. Analysis of the cervical regional alignment with respect to overall spinal pelvic alignment is emerging and critical. Cervical myelopthay and sagittal alignment of the cervical spine are closely related as cervical deformity can lead to spinal cord compression and tension. Conclusion. Cervical deformity correction should take on a comprehensive approach in assessing global cervical-pelvic relationships and the radiographical parameters that effect health-related quality of life scores are not well-defined. Cervical alignment may be important in assessment and treatment of cervical myelopathy. Future work should concentrate on correlation of cervical alignment parameters to disability scores and myelopathy outcomes. Summary Statements. Statement 1: Cervical sagittal alignment (cervical SVA and kyphosis) is related to thoracolumbar spinal pelvic alignment and to T1 slope. Statement 2: When significant deformity is clinically or radiographically suspected, regional cervical and relative global spinal alignment should be evaluated preoperatively via standing 3-foot scoliosis X-rays for appropriate operative planning. Statement 3: Cervical sagittal alignment (C2-C7 SVA) is correlated to regional disability, general health scores and to myelopathy severity. Statement 4: When performing decompressive surgery for CSM, consideration should be given to correction of cervical kyphosis and cervical sagittal imbalance (C2-C7 SVA) when present.

Spontaneous improvement of cervical alignment after correction of global sagittal balance following pedicle subtraction osteotomy Presented at the 2012 Joint Spine Section Meeting Clinical article

OBJECT Sagittal spinopelvic malalignment is a significant cause of pain and disability in patients with adult spinal deformity. Surgical correction of spinopelvic malalignment can result in compensatory changes in spinal alignment outside of the fused spinal segments. These compensatory changes, termed reciprocal changes, have been defined for thoracic and lumbar regions but not for the cervical spine. The object of this study was to evaluate postoperative reciprocal changes within the cervical spine following lumbar pedicle subtraction osteotomy (PSO). METHODS This was a multicenter retrospective radiographic analysis of patients from International Spine Study Group centers. Inclusion criteria were as follows: adults (>18 years old) with spinal deformity treated using lumbar PSO, a preoperative C7-S1 plumb line greater than 5 cm, and availability of pre- and postoperative full-length standing radiographs. RESULTS Seventy-five patients (60 women, mean age 59 years) were included. The lumbar PSO significantly improved sagittal alignment, including the C7-S1 plumb line, C7-T12 inclination, and pelvic tilt (p <0.001). After lumbar PSO, reciprocal changes were seen to occur in C2-7 cervical lordosis (from 30.8° to 21.6°, p <0.001), C2-7 plumb line (from 27.0 mm to 22.9 mm), and T-1 slope (from -38.9° to -30.4°, p <0.001). Ideal correction of sagittal malalignment (postoperative sagittal vertical alignment < 50 mm) was associated with the greatest relaxation of cervical hyperlordosis (-12.4° vs -5.7°, p = 0.037). A change in cervical lordosis correlated with changes in T-1 slope (r = -0.621, p <0.001), C7-T12 inclination (r = 0.418, p <0.001), T12-S1 angle (r = -0.339, p = 0.005), and C7-S1 plumb line (r = 0.289, p = 0.018). Radiographic parameters that correlated with changes in cervical lordosis on multivariate linear regression analysis included change in T-1 slope and change in C2-7 plumb line (r(2) = 0.53, p <0.001). CONCLUSIONS Adults with positive sagittal spinopelvic malalignment compensate with abnormally increased cervical lordosis in an effort to maintain horizontal gaze. Surgical correction of sagittal malalignment results in improvement of the abnormal cervical hyperlordosis through reciprocal changes.

Impact of magnitude and percentage of global sagittal plane correction on health-related quality of life at 2-years follow-up.

BACKGROUND Sagittal plane malalignment has been established as the main radiographic driver of disability in adult spinal deformity (ASD). OBJECTIVE To evaluate the amount of sagittal correction needed for a patient to perceive improvement (minimal clinically important difference, MCID) in health-related quality of life (HRQOL) scores. METHODS This was a multicenter, retrospective analysis of prospectively consecutively enrolled ASD patients. Inclusion criterion was a sagittal vertical axis (SVA) >80 mm. Demographic, radiographic, and HRQOL preoperative and 2-year postsurgery data were collected. Surgical treatment was categorized based on SVA correction: <60 mm, 60 mm to 120 mm, and >120 mm. Changes in parameters were analyzed using paired t test, 1-way analysis of variance, and χ2 test. RESULTS Seventy-six patients (preoperative SVA = 140 mm) were analyzed; each subgroup revealed significant HRQOL improvements following surgery. Compared with the <60 mm correction group, the likelihood of reaching MCID was significantly improved for the >120 mm group (Oswestry Disability Index) but not for the 60 mm to 120 mm group. A significantly greater likelihood of reaching MCID thresholds was observed for corrections above 66% of preoperative SVA. CONCLUSION Best HRQOL outcomes for ASD patients with severe sagittal plane deformity were obtained with a correction >120 mm for SVA and at least 66% of correction. Although lesser amounts of SVA correction yielded clinical improvement, the rate of MCID threshold improvement was not significantly different for mild or modest corrections. These results underline the need for complete sagittal plane deformity correction if high rates of HRQOL benefit are sought for patients with marked sagittal plane deformity.

Pelvic tilt measurement before and after total hip arthroplasty.

INTRODUCTION Most computer-assisted navigation systems used in total hip arthroplasty (THA) reference the anterior pelvic plane, which connects the anterior superior iliac spines and the pubic symphysis. The pelvic tilt is defined as the angle between this anterior pelvic plane (APP) and a vertical line in the standing position. Important interindividual variations of this angle have been reported and may affect final functional anteversion of the acetabular cup. The preoperative value of the pelvic tilt has been included in computer-assisted navigation systems to improve acetabular cup positioning. However, there is no data available which strongly confirms the consistency of this angle for each individual after hip prosthesis implantation. HYPOTHESIS The orientation of the APP in the standing position is not significantly modified after THA. OBJECTIVES To evaluate in a prospective manner, the reproducibility of pelvic tilt measurement and its variability between THA preoperative and 3-year postoperative measurements. MATERIALS AND METHODS A lateral teleradiograph of the pelvis and dorsolumbar spine was obtained in the standing position preoperatively and 3 years after THA. Fifty patients undergoing THA performed by a single operator via an anterolateral approach (26 males and 24 females) were included prospectively. The pelvic tilt was measured on radiographs by two independent observers. The angle was defined as positive in case of pelvis retroversion relative to the vertical plane and negative in case of anteversion. Bland-Altman analysis was used to assess levels of agreement between both operator measurements while preoperative and last follow-up measurements were compared using the Student t-test for unpaired samples. RESULTS The level of agreement between measurements of both operators was satisfactory. Mean preoperative pelvic tilt was 4.68 degrees +/-0.68 S.D. (-6 degrees to 14 degrees), and 4.78 degrees +/-0.64 S.D. (-5 degrees to 14 degrees) at last follow-up. The mean difference between preoperative and last follow-up measurements was 3 degrees +/-0.3 S.D. There was no statistically significant variation between preoperative and 3-year follow-up values (p>0.05). Ninety-five percent of the patients had less than a 5 degrees difference between both measurements while 5% had a difference ranging from 5 degrees to 10 degrees ; none of the patients reported a variation greater than 10 degrees . DISCUSSION Our findings show no significant variation in pelvic tilt between preoperative and 3-year follow-up values after THA. Therefore, the individual preoperative value of this angle should be integrated to achieve proper acetabular cup placement during THA especially when using computed assisted navigation based on the APP.

Posterior global malalignment after osteotomy for sagittal plane deformity: it happens and here is why.

Study Design. Multicenter, retrospective analysis of 183 consecutive patients undergoing lumbar osteotomy. Objective. To evaluate cause and impact of posterior postoperative alignment. Summary of Background Data. Sagittal malalignment in the setting of adult spinal deformity (ASD) has shown significant correlation with pain and disability. Surgical treatment often entails correction of deformity by pedicle subtraction osteotomies (PSO). Key radiographical spinopelvic objectives to reach improvement in clinical outcomes have been previously reported. Although anterior alignment is a cause of poor outcomes, the impact and cause of posterior spinal alignment by PSO has not been reported. Methods. The patient inclusion criteria were age, more than 18 years, with a diagnosis of sagittal plane deformity (C7 plumbline offset >5 cm, a pelvic tilt >20°, or a lumbar lordosis to pelvic incidence mismatch of ≥10°) requiring a surgical procedure involving a lumbar posterior osteotomy and a long fusion. Patients were divided into 3 groups based on postoperative sagittal vertical axis (SVA): neutral alignment (0 < SVA < 50 mm), anterior alignment (SVA > 50 mm), and posterior alignment (SVA < 0 mm). All patients underwent pre- and postoperative full-length sagittal spine radiography. Differences between groups were evaluated using ANOVA and &khgr;2 analysis. Results. Seventy-six patients were postoperatively classified in the anterior group: 59 in the neutral group and 48 in the posterior group. These groups were comparable preoperatively in terms of surgical status (revision vs. primary surgery) and regional alignment (lumbar lordosis and thoracic kyphosis). The patients with posterior alignment were younger and had a significantly lower pelvic incidence (53° vs. 62°), preoperative pelvic tilt (30 vs. 36°), SVA (94 vs. 185 mm) and cervical lordosis (16° vs. 25°) than patients in the anterior alignment group. No significant differences were found in terms surgical procedure. Patients in the posterior alignment group demonstrated a significantly greater change in SVA and pelvic tilt correction (P < 0.05) but with a lower gain in thoracic kyphosis (5 vs. 12°) and reduction of cervical lordosis (4° vs. 22°). Conclusion. A significantly lower pelvic incidence and lack of restoration of thoracic kyphosis may lead to sagittal overcorrection with a posterior alignment. Although the clinical significance of posterior malalignment is still unclear, this study showed a compensatory loss of cervical lordosis in these patients. Particular attention must be paid to preoperative planning before sagittal realignment procedures. Further study will be necessary to evaluate long-term clinical outcomes of these patients.

Limb lengthening and deformity correction in children using hexapodal external fixation: preliminary results for 36 cases.

Limb deformities in children can be corrected using different techniques, notably external fixation following the Ilizarov principles. However, correction can be difficult in cases of multiple deformities. In 1994, Charles Taylor developed a new computer-assisted hexapodal external fixator system to treat these pathologies, the Taylor Spatial Frame. The objective of this study was to evaluate the results obtained with this technique in treating lower-limb deformities in children. Thirty-six patients were included in this prospective study, with a mean age of 11.1 years. The etiologies were distributed into six groups: congenital pathologies in 17 cases, fractures in five cases, post-traumatic pathologies in two cases, postinfectious sequelae in three cases, achondroplasia in three cases, and other causes in the last six cases. A total of 67 deformities in the three spatial planes were found in the entire group of patients. The procedure consisted of lengthening, correcting the axis, or both simultaneously. All the patients were managed with the same protocol: placement of an external fixator, AP and lateral X-rays, and planning of the correction using dedicated software. In this group of 36 patients, the fixator was worn for a mean 183 days; when lengthening was performed, a mean 4.3cm was gained with a healing index of 38.2 days/cm. Of the 67 initial deformities, 91% were corrected. The most frequently encountered complications were a superficial infection in 22.2% of the cases; one deep infection was also noted as well as three bone regenerate fractures. Use of this computer-assisted fixation system seems effective in treating complex deformities of the limbs in children, and allows treating several deformities simultaneously.

Clinical results of lumbar total disc arthroplasty in accordance with Modic signs, with a 2-year-minimum follow-up.

Study Design. Prospective Study. Objective. The aim of this prospective study is to analyze the influence of Modic type on the clinical results of lumbar total disc arthroplasty. Summary of Background Data. Some patients with lumbar disc degeneration have endplate signal changes on magnetic resonance images, which have been classified by Modic. Modic-1 endplates changes are associated with an inflammatory phase of the disease whereas Modic-2 endplates changes correspond to a quiescent phase with a fatty replacement. The effect of Modic endplate changes on the clinical results of lumbar fusion has been studied by multiple authors, but the influence of Modic type on clinical outcomes of lumbar disc replacement is not known. Methods. A total of 221 patients with a mean age of 42 years were included in this study. Of which, 107 patients were classified Modic 0, 65 Modic 1, and 49 Modic 2. Clinical evaluation (Oswestry Disability Index [ODI], lumbar and radicular pain using the Visual Analog Score [VAS]) was performed preoperatively and at 3, 6, 12, and 24 months minimum postoperatively. Results. Mean follow-up was 30 months (24–72 months). Significant clinical improvement (P < 0.05) was observed in pain and ODI between the preoperative evaluation and final follow-up. Multivariate analysis between the 3 groups demonstrated a significant difference in Oswestry Disability Index (size of the effect was measured at −0.3 [–0.55–0.04]) and on the radicular pain (size of the effect was measured at −0.4 [–0.7–0.1]), with lower scores in the group classified Modic 1. Conclusion. Superior results were achieved in the group of patients with Modic-1 endplate changes on magnetic resonance images. These data may be helpful in patient selection and in preoperative patient counseling.

Hexapodal external fixation in the management of children tibial fractures

Some tibial fractures in children require surgical osteosynthesis, mostly achieved by an internal fixation. Indications for external fixation in the management of tibial fractures in children are limited to specific clinical situations when conventional treatments are contraindicated. The aim of this study is to report the results of tibial fractures management by hexapodal external fixation. Eleven children were included in this study and all of them were treated by a specific hexapodal external fixator, with a 12-month mean follow-up. In the whole series, initial deformities were perfectly corrected in nine cases, two patients showed residual deformity that did not require further surgery. The mean time for external fixation was 98 days. Hexapodal external fixation seems to be a simple and effective definitive method for the correction of three-dimensional traumatic deformities requiring surgical stabilization. Long-term follow-up will be necessary to evaluate residual deformities at the end of patients growth.