Brandon B. Carlson

Converting SRS-24, SRS-23, and SRS-22 to SRS-22r: establishing conversion equations using regression modeling.

Study Design. Cross-sectional mail questionnaire. Objective. Assess the feasibility of translating total and domain scores from Scoliosis Research Society (SRS)-24, SRS-23, and SRS-22 to SRS-22r. Summary of Background Data. Three successive editions of the original SRS-24 health-related quality-of-life questionnaire have resulted from efforts to improve its psychometric properties and validate its use in patients down to 10 years of age. This resulted in the need to establish, if possible, conversion equations to the last and most thoroughly validated version, SRS-22r. Methods. A consolidated questionnaire of 49 questions that incorporated the various questions in the four questionnaires was mailed to a consecutive series of 235 patients who had received primary posterior or anterior instrumentation and arthrodesis to treat adolescent idiopathic scoliosis. Regression modeling was used to establish conversion equations from the SRS-24, SRS-23, and SRS-22 to the SRS-22r. Results. One hundred twenty-one of the 235 patients (51%), aged 23.3 ± 4.52 years (range 14.2–34.6 years), returned the questionnaire at 8.6 ± 4.00 years (range 2.3–15.9 years) following surgery. Estimation of SRS-22r questionnaire and nonmanagement domains total scores and mean scores from SRS-22 and SRS-23 scores is excellent (R2 scores of 0.97–0.99) and good for SRS-24 scores (R2 scores of 0.80–0.82, improving to 0.86 and 0.87 after minimal domain reconfiguration). Estimation of SRS-22r individual domain total scores and mean scores from SRS-22 and SRS-23 is good to excellent (R2 scores of 0.81–0.99). Minimal domain reconfiguration improves conversion from SRS-24 pain from R2 = 0.71 to 0.76, which are both fair; SRS-24 function from R2 = 0.69 and 0.74 to 0.83, from poor and fair to good; and SRS-24 satisfaction/dissatisfaction with management from R2 = 0.64 to 0.80, from poor to good. Conversion of SRS-24 self-image is poor (R2 = 0.60) despite the correlation being statistically significant. Conclusion. With one exception, SRS-24, SRS-23, and SRS-22 questionnaire, nonmanagement domains, and individual domain total scores and mean scores can be translated to SRS-22r scores with fair to excellent accuracy, which is further improved in some instances by minimal domain reconfigurations. The sole exception is SRS-24 self-image, which translates poorly.

Comparison of trunk and spine deformity in adolescent idiopathic scoliosis

BackgroundCobb measurement of standing radiographs is the standard for clinical assessment of coronal spinal deformity. Angle of trunk inclination (ATI) is an accepted clinical measurement of trunk asymmetry, and has variable reported correlations with Cobb angles. Transverse plane spine deformity is most accurately measured using axial computed tomography. Aaro and Dahlbourn’s technique for quantifying apical vertebral rotation with respect to the sagittal plane (RAsag) is commonly reported in the literature. To our knowledge no study has correlated ATI with RAsag. The purpose of this study was to determine the relationship between commonly used measures of trunk and spine deformity.MethodsSixteen females that underwent preoperative apical vertebra(e) CT scans were retrospectively studied. Thoracic and thoracolumbar RAsag measurements were date-matched to clinically obtained ATI and Cobb measurements. Two-tailed Pearson correlations were calculated; α = 0.01.ResultsMedian patient age was 14.6 years (11–19); BMI 19.4 (16.0-25.5). Curve patterns: Lenke 1 (5); 2 (5); 3 (1); 4 (1); 5 (2): 6 (2). Twenty-six curves (15T; 11TL) with complete, date-matched data points were analyzed. In thoracic curves, ATI correlated with Cobb (r = 0.711, P < 0.004) and RAsag (r = 0.730, P <0.003). ATI was inversely correlated with Cobb flexibility (r = −0.647, P < 0.01). In thoracolumbar curves, ATI correlated with Cobb (r = 0.789, P < 0.005), and RAsag (r = 0.771, P < 0.006) but not Cobb flexibility (r = − 0.452, P = 0.190).ConclusionsTrunk and spine thoracic and thoracolumbar transverse plane deformity are correlated, as are trunk transverse plane and spine coronal plane deformity. Increasing trunk deformity limits thoracic, but not thoracolumbar spine flexibility.

Identification of Scoliosis Research Society-22r Health-Related Quality of Life questionnaire domains using factor analysis methodology.

Study Design. Cross-sectional mail questionnaire. Objective. Examination of the underlying construct validity of the Scoliosis Research Society-22r (SRS-22r) Health-Related Quality of Life (HRQoL) Questionnaire using factor analysis. Summary of Background Data. The original SRS-24 HRQoL questionnaire has undergone a series of modifications in an effort to further improve its psychometric properties and validate its use in patients from 10 years of age until well into adulthood. The SRS-22r questionnaire is the result of this effort. To date, the underlying construct validity of the original English version has not been analyzed by factor analysis. Methods. A questionnaire including all questions on the SRS-24, -23, -22, and -22r questionnaires (49 total questions) was mailed to a consecutive series of 235 patients who had received primary posterior or anterior instrumentation and arthrodesis. Domain structure of the SRS-22r questions was analyzed using iterated principal factor analysis with orthogonal rotation. Results. One hundred twenty-one (51%) of the patients, age 23.34 ± 4.52 years (range, 14.16–34.57 years), returned the questionnaire at 8.63 ± 4.00 years (range, 2.32–15.94 years) following surgery. Factor analysis using all 22 questions resulted in 3 factors with many shared items because of significant collinearity of the satisfaction/dissatisfaction with management questions with the others. After 18 iterations, factor analysis using the 20 nonmanagement questions revealed 4 factors that explained 98% of the variance. These factors parallel the assigned domains of the SRS-22r questionnaire. Three questions (2 self-image and 1 function) were identified that had high loading in 2 factors. However, internal consistency was best when 2 of the questions (1 self-image and 1 function) were retained in their assigned SRS-22r domains and the third decreased self-image internal consistency by only 0.01%. The internal consistencies (Cronbach &agr;) of the assigned SRS-22r nonmanagement domains were excellent or very good: function 0.83, pain 0.87, self-image 0.80, and mental health 0.90. For the management domain it was good: 0.73. Conclusion. Factor analysis of the SRS-22r HRQoL confirms placement of the 20 nonmanagement domain questions in the assigned 4 domains, all with excellent or very good internal consistency.

Transverse plane pelvic rotation increase (TPPRI) following rotationally corrective instrumentation of adolescent idiopathic scoliosis double curves

BackgroundWe have occasionally observed clinically noticeable postoperative transverse plane pelvic rotation increase (TPPRI) in the direction of direct thoracolumbar/lumbar rotational corrective load applied during posterior instrumentation and arthrodesis for double (Lenke 3 and 6) adolescent idiopathic scoliosis (AIS) curves. Our purposes were to document this occurrence; identify its frequency, associated variables, and natural history; and determine its effect upon patient outcome.MethodsTransverse plane pelvic rotation (TPPR) can be quantified using the left/right hemipelvis width ratio as measured on standing posterior-anterior scoliosis radiographs. Descriptive statistics were done to determine means and standard deviations. Non-parametric statistical tests were used due to the small sample size and non-normally distributed data. Significance was set at P < 0.05.ResultsSeventeen of 21 (81%) consecutive patients with double curves (7 with Lenke 3 curves and 10 with Lenke 6) instrumented with lumbar pedicle screw anchors to achieve direct rotation had a complete sequence of measurable radiographs. While 10 of these 17 had no postoperative TPPRI, 7 did all in the direction of the rotationally corrective thoracolumbar instrumentation load. Two preoperative variables were associated with postoperative TPPRI: more tilt of the vertebra below the lower instrumented vertebra (-23° ± 3.1° vs. -29° ± 4.6°, P = 0.014) and concurrent anterior thoracolumbar discectomy and arthrodesis (5 of 10 vs. 7 of 7, P = 0.044). Patients with a larger thoracolumbar/lumbar angle of trunk inclination or larger lower instrumented vertebra plus one to sacrum fractional/hemicurve were more likely to have received additional anterior thoracolumbar discectomy and arthrodesis (c = 0.90 and c = 0.833, respectively).Postoperative TPPRI resolved in 5 of the 7 by intermediate follow-up at 12 months. Patient outcome was not adversely affected by postoperative TPPRI, whether or not it persisted.ConclusionsOur findings suggest that TPPRI is a decompensation caused by extension of the corrective thoracolumbar rotational load into the lumbosacral hemicurve below. As posterior instrumentation of adolescent idiopathic scoliosis becomes increasingly more effective in the transverse plane, postoperative TPPRI may become more widely noticed. This study provides some assurance that recompensation usually occurs, but that in either event TPPRI does not seem to affect clinical outcome.

Backfilling of iliac crest defects with hydroxyapatite-calcium triphosphate biphasic compound: a prospective, randomized computed tomography and patient-based analysis

BACKGROUND CONTEXT Hydroxyapatite-calcium triphosphate (HCT) biphasic compounds are known to be efficacious in filling bone voids. No large study to date has assessed their radiographic efficacy in iliac crest voids with computed tomography (CT) analysis at a 2-year follow-up. PURPOSE To assess whether backfilling iliac crest defects with HCT biphasic compound decreases donor site pain and what effect backfilling has on CT appearance of the donor ilium. STUDY DESIGN Prospective randomized clinical trial. PATIENT SAMPLE Adult patients with spinal disorders undergoing spinal arthrodesis requiring posterior iliac crest bone grafting. OUTCOME MEASURES Physician-administered visual analog scale (VAS) and pre- and postoperative CT analysis was performed. METHODS This prospective, randomized, single-blind study followed patients requiring nonstructural posterior iliac crest harvest as part of spinal disorder treatment for 2 years. The harvest technique preserved both cortical tables and their periostea. All patients were randomized to backfill of HCT or no backfill. All patients had a CT of the pelvis immediately postoperative and at the 2-year follow-up. Computed tomography analysis was performed by a board-certified neuroradiologist. Analysis included qualitative assessment of the ilia appearance and defect density quantified in Hounsfield units. All patients completed VAS of their donor site pain (0-10, from low to high) at 6 weeks and 2 years postoperatively. RESULTS Thirty-seven of 40 (17 women and 20 men) subjects returned for a mean 23.9-month follow-up (range, 22-29 months). The average age was 51.7 years (range, 27-79 years). Eighteen patients were in the backfill group (BF) and 19 were in the control group (C). There was no statistically significant difference in pain at 6 weeks or 2 years between the two groups. Bone density significantly decreased from postoperative to 2 years in BF (implying resorption of HCT and replacement of host bone) and significantly increased in C (implying reformation of host bone). Both groups had similar cortical defect repair. The backfill group had significantly better medullary defect repair (p<.01, Fisher exact test). CONCLUSIONS Backfilling iliac crest voids with HCT biphasic compound does not significantly decrease donor site pain. Both the backfilled and control defects reformed bone over the 2-year period, with BF having significantly less medullary defects than C.

Outcomes and Complications of Extension of Previous Long Fusion to the Sacro-Pelvis: Is an Anterior Approach Necessary?

BACKGROUND Patients with previous multilevel spinal fusion may require extension of the fusion to the sacro-pelvis. Our objective was to evaluate the outcomes and complications of these patients, stratified based on whether the revision was performed using a posterior-only spinal fusion (PSF) or combined anterior-posterior spinal fusion (APSF). METHODS A retrospective, multicenter evaluation of adults (>18 years old) with a history of prior spinal fusion for scoliosis (≥4 levels) terminating in the distal lumbar spine requiring extension of fusion to the sacro-pelvis (including iliac fixation in all cases), with minimum 2-year follow-up, was performed. Patients were stratified based on approach (APSF vs. PSF) and inclusion of pedicle subtraction osteotomy (PSO). The PSF group included patients treated with an anterior interbody fusion done through a posterior approach, whereas patients in the APSF group all had both anterior and posterior surgical approaches. Clinical outcomes were based on the Scoliosis Research Society (SRS-22) questionnaire. RESULTS Between 1995 and 2006, 45 patients (mean age = 49 years) met inclusion criteria, with a mean follow-up of 41.9 months (range 24 to 135 months). Demographic, preoperative, operative, and postoperative radiographic, SRS-22, and follow-up results were similar between APSF (n=30) and PSF (n=15) groups. The APSF group had more complications (13 of 30 vs. 3 of 15) and a greater number of pseudarthrosis (4 of 30 vs. 0 of 15) than the PSF group; however, these differences did not reach statistical significance. Patients treated with a PSO (n=13) had greater sagittal vertical axis correction (7.7 cm vs. 2.2 cm; P=.04) compared with patients not treated with a PSO (n=32). There were no differences in complication rates or follow-up SRS-22 scores based on whether a PSO was performed (P>.05). CONCLUSIONS Among adults with previously treated scoliosis requiring extension to the sacro-pelvis, PSF produced radiographic fusion and clinical outcomes equivalent to APSF, whereas complication rates may be lower. PSO resulted in greater sagittal plane correction, without an increase in overall complication rates.

Recidivism Rates After Smoking Cessation Before Spinal Fusion

Tobacco use has documented negative effects on perioperative complications and clinical outcomes. Smoking cessation before spinal surgery may improve clinical outcomes. The goal of this study was to determine the recidivism rate after smoking cessation before spinal fusion. A prospective observational study was performed at the University of Kansas Medical Center between 2006 and 2011. All patients with serum-confirmed nicotine cessation before spinal fusion surgery were eligible. Smoking status was determined with questionnaires at 3 months, 6 months, and 1 year postoperatively. All reported nonsmokers had confirmatory serum nicotine and cotinine tests. Two-tailed Pearson chi-square and independent t tests were conducted, and significance was set at α=0.05. A total of 42 subjects (21 women, 21 men) with confirmed preoperative serum-negative test results were prospectively enrolled over a period of 3.9 years. Of these patients, 1 opted out at 6 months and 1 died of unknown cause. The findings showed a recidivism rate (response rate) of 60% (40 of 41) at 3 months, 61% (33 of 41) at 6 months, and 68% (25 of 40) at 1 year. One case of asymptomatic pseudarthrosis occurred 1 year postoperatively in a confirmed nonsmoker. No correlation was found between smoking status at 3 months and sex, primary vs revision surgery, or complications (P>.05). Smokers who relapsed at 3 months were older than nonsmokers (55.2 vs 44.2 years, respectively; P=.03). Some patients are willing to cease smoking before spinal fusion for optimal clinical outcomes; however, the rate of recidivism is high (60%) within the first 3 months post-operatively.

Regional Bone Mineral Density Differences measured by QCT: Does the Standard Clinically Used L1-L2 Average Correlate with the Entire Lumbosacral Spine?

BACKGROUND CONTEXT Quantitative computed tomography (QCT) of the lumbar spine is used as an alternative to dual-energy X-ray absorptiometry in assessing bone mineral density (BMD). The average BMD of L1-L2 is the standard reportable metric used for diagnostic purposes according to current recommendations. The density of L1 and L2 has also been proposed as a reference value for the remaining lumbosacral vertebrae and is commonly used as a surrogate marker for overall bone health. Since regional BMD differences within the spine have been proposed, it is unclear if the L1-L2 average correlates with the remainder of the lumbosacral spine. PURPOSE The aim of this study was to determine possible BMD variations throughout the lumbosacral spine in patients undergoing lumbar fusion and to assess the correlation between the clinically used L1-L2 average and the remaining lumbosacral vertebral levels. STUDY DESIGN/SETTING This is a retrospective case series. PATIENT SAMPLE Patients undergoing posterior lumbar spinal fusion from 2014 to 2017 at a single, academic institution with available preoperative CT imaging were included in this study. OUTCOME MEASURES The outcome measure was BMD measured by QCT. METHODS Standard QCT measurements at the L1 and L2 vertebra and additional experimental measurements of L3, L4, L5, and S1 were performed. Subjects with missing preoperative lumbar spine CT imaging were excluded. The correlations between the L1-L2 average and the other vertebral bodies of the lumbosacral spine (L3, L4, L5, S1) were evaluated. RESULTS In total, 296 consecutive patients (55.4% female, mean age of 63.1 years) with available preoperative CT were included. The vertebral BMD values showed a gradual decrease from L1 to L3 and increase from L4 to S1 (L1=118.8 mg/cm3, L2=116.6 mg/cm3, L3=112.5 mg/cm3, L4=122.4 mg/cm3, L5=135.3 mg/cm3, S1=157.4 mg/cm3). There was strong correlation between the L1-L2 average and the average of the other lumbosacral vertebrae (L3-S1) with a Pearsons correlation coefficient (r=0.85). We also analyzed the correlation between the L1-L2 average and each individual lumbosacral vertebra. Similar relationships were observed (r value, 0.67-0.87), with the strongest correlation between the L1-L2 average and L3 (r=0.87). CONCLUSIONS Our data demonstrate regional BMD differences throughout the lumbosacral spine. Nevertheless, there is high correlation between the clinically used L1-L2 average and the BMD values in the other lumbosacral vertebrae. We, therefore, conclude the standard clinically used L1-L2 BMD average is a useful bone quantity measure of the entire lumbosacral spine in patients undergoing lumbar spinal fusion.