Martin Gehrchen

A proposed set of metrics for standardized outcome reporting in the management of low back pain

Background and purpose — Outcome measurement has been shown to improve performance in several fields of healthcare. This understanding has driven a growing interest in value-based healthcare, where value is defined as outcomes achieved per money spent. While low back pain (LBP) constitutes an enormous burden of disease, no universal set of metrics has yet been accepted to measure and compare outcomes. Here, we aim to define such a set. Patients and methods — An international group of 22 specialists in several disciplines of spine care was assembled to review literature and select LBP outcome metrics through a 6-round modified Delphi process. The scope of the outcome set was degenerative lumbar conditions. Results — Patient-reported metrics include numerical pain scales, lumbar-related function using the Oswestry disability index, health-related quality of life using the EQ-5D-3L questionnaire, and questions assessing work status and analgesic use. Specific common and serious complications are included. Recommended follow-up intervals include 6, 12, and 24 months after initiating treatment, with optional follow-up at 3 months and 5 years. Metrics for risk stratification are selected based on pre-existing tools. Interpretation — The outcome measures recommended here are structured around specific etiologies of LBP, span a patient’s entire cycle of care, and allow for risk adjustment. Thus, when implemented, this set can be expected to facilitate meaningful comparisons and ultimately provide a continuous feedback loop, enabling ongoing improvements in quality of care. Much work lies ahead in implementation, revision, and validation of this set, but it is an essential first step toward establishing a community of LBP providers focused on maximizing the value of the care we deliver.

No difference in clinical outcome after posterolateral lumbar fusion between patients with isthmic spondylolisthesis and those with degenerative disc disease using pedicle screw instrumentation: a comparative study of 112 patients with 4 years of follow-up

Abstract. We compared the clinical outcome after spinal fusion between patients with isthmic spondylolisthesis and those with degenerative disc disease of the lumbar spine, using multiple logistic regression analysis. A questionnaire describing medication, pain, vocational status and patient satisfaction was mailed to all the patients at a median interval of 4 years after their operation. Fusion was evaluated on plain radiographs at a minimum of 12 months after surgery, and patients were classified as fused or not fused. The overall satisfaction rate was 70%. The results of the present study showed no difference in the outcome after spinal fusion between the two groups of patients. The factors that significantly increased the likelihood of an optimal result – defined as patient satisfaction, return to work, and reduced medication – were male gender, being in work prior to surgery, and being a non-smoker. Since spinal fusion is an expensive treatment with potentially serious risks, and leaves one-third of the patients with an unsatisfactory result, we believe that more studies focusing on the indications for surgery should be performed.

Nonorganic pain drawings are associated with low psychological scores on the preoperative SF-36 questionnaire in patients with chronic low back pain

Abstract The Short Form 36 questionnaire (SF-36) measures general health and well-being. Within the last 5 years it has been used increasingly to characterise patients in the medical literature. Relatively few studies have used the SF-36 on patients with chronic low back pain undergoing preoperative evaluation, but results suggest that it may be predictive of surgical outcome. Pain drawings are a routine part of evaluation prior to spinal surgery in several centres, since their classification of organic or nonorganic has been shown in some studies to correlate well with psychological characteristics predicting poor outcome. The purpose of the present study was to assess possible correlations between nonorganic pain drawings and the psychological scales in the SF-36. We included 128 patients in the study, all of them referred from other hospitals. Previous spinal surgery had been undergone by 25%, and 59% required daily medication because of low back pain. All patients completed pain drawings using predefined symbols These pain drawings were scored dichotomously as organic or nonorganic based on a brief description of a typical nonorganic characteristics. Patients also completed the Danish version of the SF-36 questionnaire. Statistical analysis was performed using logistic regression analysis. The pain drawing classification was used as the dependent variable and scores on the eight scales of the SF-36 as independent variables. P values of <0.05 were considered significant. The mean scores of the patient population on all eight scales were significantly lower than Danish norms. The only scales that correlated with the presence of nonorganic pain drawings were emotional role (RE) and mental health (MH), both measuring psychological health. The odds ratio (OR) of receiving a nonorganic pain drawing was 22 (95% confidence interval, or CI, 7–65) if the scores on RE and MH were more than 2 standard deviations (SD) below the Danish norm. This is the first study providing evidence that pain drawing ratings are influenced by the psychological scales of the SF-36. The clinical relevance of this observation regarding prediction of outcome after spinal surgery should be assessed in future studies.

Use of Supplemental Short Pre-Contoured Accessory Rods and Cobalt Chrome Alloy Posterior Rods Reduces Primary Rod Strain and Range of Motion Across the Pedicle Subtraction Osteotomy Level: An In Vitro Biomechanical Study.

Study Design. In vitro cadaveric biomechanical study. Objective. To assess effects of 4-rod reconstruction, rod material, and anterior column support on motion and surface rod strain in a pedicle subtraction osteotomy model. Summary of Background Data. Pedicle subtraction osteotomy (PSO) can correct significant sagittal deformity of the lumbar spine; however, revision rates are high. To reduce rod strain and the incidence of rod fracture, clinical use of multi-rod construction, cobalt chrome (CoCr) alloy rods, and interbody spacers adjacent to PSO has been proposed. Investigating both motion and rod strain is necessary to determine the biomechanical efficacy of these techniques. Methods. Five specimens (T12–S1) underwent PSO at L3 with pedicle screw stabilization at L1–S1. Pedicle subtraction was adjusted to achieve a final lordosis of 70°. Flexion-extension (FE), lateral bending, and axial rotation were applied. Linear strain gauges measured surface rod strain during FE on primary and accessory rods at PSO level. Testing evaluated (1) accessory rods (4-Rod) added at PSO level versus primary rods (2-Rod); (2) Ti versus CoCr rods; and (3) lateral interbody spacers (S) inserted adjacent to PSO. One-way and three-way analysis of variance was performed (P ⩽ 0.05). Results. All constructs significantly reduced FE and lateral bending motion relative to intact (P < 0.001). The main effect of accessory rods in reducing FE motion was significant (P = 0.021). Accessory and CoCr rods reduced relative surface strain on the primary rod, irrespective of construct (P < 0.001). CoCr 4-Rod + S provided the greatest reduction in strain (76% decrease; P = 0.003). Conclusion. Accessory and CoCr rods provided greatest reduction in motion and rod strain at PSO level. Interbody devices minimally affected motion-induced strain and might act primarily to maintain disc height. Clinicians must assess whether surface strain and motion reduction minimize the incidence of rod fracture. Level of Evidence: N/A

Morbidity and mortality of complex spine surgery: a prospective cohort study in 679 patients validating the Spine AdVerse Event Severity (SAVES) system in a European population

BACKGROUND CONTEXT Most literature on complications in spine surgery has been retrospective or based on national databases with few variables. The Spine AdVerse Events Severity (SAVES) system has been found reliable and valid in two Canadian centers, providing precise information regarding all adverse events (AEs). PURPOSE This study aimed to determine the mortality and examine the incidence of morbidity in patients undergoing complex spinal surgery, including pediatric patients, and to validate the SAVES system in a European population. STUDY DESIGN A prospective, consecutive cohort study was conducted using the SAVES version 2010 in the period from January 1, 2013 until December 31, 2013. A retrospective analysis was performed on all patients operated from November 1, 2011 until October 31, 2012 for comparison. PATIENT SAMPLE Patients undergoing spinal surgery at a tertiary referral center comprised the patient sample. OUTCOME MEASURES Morbidity and mortality were determined according to the newest version of the SAVES system and compared with the Canadian cohort. Other outcomes were length of stay, readmission, unplanned second surgery during index admission, as well as wound infections requiring revision. METHODS All patients undergoing spinal surgery at an academic tertiary referral center in the study period were prospectively included. The newest version of SAVES system was used, and a research coordinator collected all intraoperative and perioperative data prospectively. Once a week all patients were reviewed for additional events, validation of the data, and clarification of any questions. Patients were grouped according to the type of admission (elective of emergency) and age, and subgrouped according to a major diagnostic group. The survival status was registered on January 31, 2014 to obtain 30-day survival. RESULTS A total of 679 consecutive cases were included with 100% data completion. The in-hospital mortality was 1.3% and the 30-day mortality was 2.7%; all occurring after emergency procedures. The number of intraoperative AEs was 162 (overall incidence 20%), and the number of postoperative AEs was 1,415 (overall incidence 77%). Of the patients, 2.2% had postoperative infections requiring surgical revision. CONCLUSIONS A prospective registration improves AE recognition, and our data confirm the generalizability of the SAVES system to pediatric and non-Canadian populations.

A Uniquely Shaped Rod Improves Curve Correction in Surgical Treatment of Adolescent Idiopathic Scoliosis.

Study Design. A retrospective cohort study. Objective. The aim of this study is to determine the initial curve correction in patients surgically treated for adolescent idiopathic scoliosis (AIS) using either beam-like rods (BRs) or traditional circular rods (CRs). Summary of Background Data. Posterior fusion using all pedicle screw instrumentation has become the standard for the surgical treatment of AIS. Traditionally, the rod is circular in the cross-sectional plane. Recent biomechanical studies suggest that a beam-like structure of the rod may enhance the stiffness of the construct and thereby possibly improve curve correction. Methods. Two consecutive series of patients surgically treated for AIS between May 2011 and May 2015 were included in the study. Patients were all treated with an ultralow profile all-pedicle screw implant system. In the first series, conventional 5.5 mm CoCr CR were used, and in the second series, 5.5 mm CoCr BR were used. Antero-posterior and lateral radiographs preoperatively and within seven days after surgery were used to measure the correction obtained. Results. The first 60 patients were operated with CR and the subsequent 69 with BR. There was no statistical difference in age, gender, preoperative curve magnitude, Lenke type, or number of levels instrumented (P = 0.451). Major curve correction was significantly better in the BR group than in the CR group (66 vs. 57%) (P < 0.001). We found no difference in preoperative flexibility, secondary curve correction, sagittal balance, or coronal balance (P > 0.058). A postoperative decrease in thoracic kyphosis was seen with no significant difference between groups. Median T5-T12 change was −7° versus −3° for BR and CR, respectively (P = 0.051). Conclusion. A BR design results in a significantly better curve correction than conventional rods, but the difference is moderate and the clinical value is uncertain. Level of Evidence: 3

Inter- and Intra-rater Agreement in Assessment of Adult Spinal Deformity Using the Scoliosis Research Society–Schwab Classification

STUDY DESIGN Cross-sectional assessment of inter- and intra-rater agreement. OBJECTIVES To assess inter- and intra-rater agreement between spine surgeons with different levels of experience in a large consecutive series of adult patients referred to a tertiary institution for evaluation of a spinal deformity using the Scoliosis Research Society (SRS)-Schwab classification. BACKGROUND The development of the SRS-Schwab classification of adult spinal deformity is based on current knowledge about relevant radiographic variables related to health-related quality of life. Clinical implementation of the classification requires satisfactory reliability. Two recent reports on agreement were based on a small selected case sample using pre-marked radiographs and a large cohort of only surgical patients, including congenital deformity. METHODS Scoliosis Research Society-Schwab classification of 67 consecutive adult patients referred for surgical evaluation of a spinal deformity was done in a blinded fashion without pre-marking by 2 senior spine surgeons, 1 attending, and 1 spine fellow. After 2 weeks, the classification was repeated on recoded radiographs. Inter- and intra-rater agreement was analyzed using Fleiss kappa statistics. Rater bias was assessed using Bhapkar test for marginal homogeneity. RESULTS According to Landis and Koch, the observed agreements were considered substantial to almost perfect for curve type and sagittal modifiers and moderate for entire grade, with no consistent differences between surgeons with different levels of experience. CONCLUSIONS The results for each individual radiographic parameter correspond to previous findings and support use of the SRS-Schwab classification in adult spinal deformity. The results for entire grade were considered only moderate. The authors recommend that it is not used as an individual parameter.

Curve Magnitude in Patients Referred for Evaluation of Adolescent Idiopathic Scoliosis: Five Years' Experience From a System Without School Screening

STUDY DESIGN Retrospective cross-sectional study. OBJECTIVES To analyze the referral pattern of patients with adolescent idiopathic scoliosis (AIS) in a tertiary hospital in a nationalized health care system without school screening and to compare curve magnitude on referral with results reported in the literature. In Denmark, school screening for AIS has not been in effect for more than two decades, and there is limited knowledge of curve magnitude and pattern of referral to specialized treatment in our country. Other studies, however, have assessed the effectiveness of school scoliosis screening. Our tertiary institution receives referrals for evaluation of AIS from general practitioners (GPs) and other hospitals or private specialists. METHOD A review was conducted on all patients diagnosed with AIS between 2010 and 2015. Data collection included age, gender, menarchal status, recommended treatment, and major curve Cobb angle for all patients aged 10-19 years referred for evaluation of AIS. Major curve magnitude was categorized as 10-19, 20-39, or ≥40 degrees, and the distribution of categories was compared to a screened population reported in the litterature. RESULTS A total of 166 of 460 newly referred AIS patients were referred from GP. Mean age was 15 years (standard deviation = 2) and median Cobb angle was 35 degrees. Overall, 33% were initially recommended treatment with a brace. This group had a median curve size of 41 degrees, and 28% presented more than 1 year past menarche. We found a significantly larger curve magnitude at the time of referral in our GP cohort compared to a screened population (p <.001), and 22% versus 8% had a Cobb angle >40 degrees (p <.001). CONCLUSION The present study confirms that in a health care system without school screening, patients with AIS referred for evaluation by GPs have larger curve sizes compared to systems with school screening. LEVEL OF EVIDENCE III.STUDY DESIGN Retrospective cross-sectional study. OBJECTIVES To analyze the referral pattern of patients with adolescent idiopathic scoliosis (AIS) in a tertiary hospital in a nationalized health care system without school screening and to compare curve magnitude on referral with results reported in the literature. SUMMARY OF BACKGROUND DATA In Denmark, school screening for AIS has not been in effect for more than two decades, and there is limited knowledge of curve magnitude and pattern of referral to specialized treatment in our country. Other studies, however, have assessed the effectiveness of school scoliosis screening. Our tertiary institution receives referrals for evaluation of AIS from general practitioners (GPs) and other hospitals or private specialists. METHOD A review was conducted on all patients diagnosed with AIS between 2010 and 2015. Data collection included age, gender, menarchal status, recommended treatment, and major curve Cobb angle for all patients aged 10-19 years referred for evaluation of AIS. Major curve magnitude was categorized as 10-19, 20-39, or ≥40 degrees, and the distribution of categories was compared to a screened population reported in the litterature. RESULTS A total of 166 of 460 newly referred AIS patients were referred from GP. Mean age was 15 years (standard deviation = 2) and median Cobb angle was 35 degrees. Overall, 33% were initially recommended treatment with a brace. This group had a median curve size of 41 degrees, and 28% presented more than 1 year past menarche. We found a significantly larger curve magnitude at the time of referral in our GP cohort compared to a screened population (p < .001), and 22% versus 8% had a Cobb angle >40 degrees (p < .001). CONCLUSION The present study confirms that in a health care system without school screening, patients with AIS referred for evaluation by GPs have larger curve sizes compared to systems with school screening. LEVEL OF EVIDENCE III.

Supine Lateral Bending Radiographs Predict the Initial In-brace Correction of the Providence Brace in Patients With Adolescent Idiopathic Scoliosis.

Study Design. Retrospective, cross-sectional. Objective. To determine the initial curve correction of the providence brace (PB) and to determine to what extend the in-brace Cobb angle corresponds to the curve seen on supine lateral bending radiographs (SLBR). Summary of Background Data. SLBR are used to assess curve flexibility in patients undergoing surgical treatment for adolescent idiopathic scoliosis (AIS). A low rate of in-brace correction (IBC) has been associated with a higher risk of curve progression, but to what extent SLBR can be used to predict IBC before initiating bracing treatment is unknown. Methods. All patients with AIS treated with the PB from January 1, 2006 to December 31, 2013 with a major curve of 25 to 45 degrees° were included. Cobb angle on SLBR before treatment and on initial standing, in-brace radiograph (IBR) were measured twice for each patient by one observer 30 days apart. Using a repeated measure mixed effect model, mean difference and 95% limits of agreement (LOA) between Cobb angles on each type of radiograph were estimated. Correction index (CI) was calculated as: curve flexibility (%)/curve correction (%). Results. A total of 127 patients were included. Mean long-standing Cobb angle was 35° (SD: 6°), which was reduced to mean 13° (SD: 8) on IBR (P < 0.05). No difference in curve correction between curve types was found when adjusting for flexibility using correction index (P = 0.77). Overall mean difference between SLBR and IBR was 0.2° (LOA ± 10°). Mean difference for thoracic curves was 0.2° (LOA ± 8°), for thoracolumbar/lumbar curves 0.9° (LOA ± 10°) and for double major curves 0.4° (LOA ± 16). Conclusion. SLBR provide a close estimation to the expected in-brace correction with a mean difference of less than one degree. SLRB could potentially serve as prognostic parameter for curve progression before initiating brace treatment. Level of Evidence: 3

Flexibility Predicts Curve Progression in Providence Nighttime Bracing of Patients With Adolescent Idiopathic Scoliosis.

Study Design. Retrospective cohort study. Objective. To determine treatment outcome with providence brace (PB) and to assess the ability of pretreatment supine lateral bending radiographs (SLBR) in predicting curve progression. Summary of Background Data. Results from treatment with the PB for adolescent idiopathic ccoliosis (AIS) have been inconsistent and further research is needed. The association between flexibility, as determined by pretreatment SLBR, and curve progression has not previously been examined. Methods. All patients treated with the PB from 2006 to 2011 who met Scoliosis Research Society (SRS) bracing criteria were included. Flexibility of the curve was determined based on SLBR and radiographic variables were registered at beginning of treatment and at skeletal maturity (SM) or before surgery. An increase in standing Cobb angle by more than 5 degrees was considered progression. Follow-up SRS-22 scores were compared with a control group with minor AIS. Analysis included multiple linear and logistic regression. Results. A total of 63 patients were included. Mean age was 13.3 years (SD: 1.5) and mean standing Cobb angle was 34° (SD: 5°). Radiographic progression was observed in 43% of patients at SM and surgical rate was 27% and 37% at SM and 2-year follow up, respectively. SRS-22 total scores were similar but the mental health score was significantly better in the control group (P = 0.042). Multiple linear regression analysis showed that decreased flexibility adjusted for age, Cobb angle, and menarchal status was significantly associated with curve progression (P < 0.001). Multiple logistic regression analysis showed that a one percent increase in flexibility was associated with a decrease in risk of curve progression ≥6° (odds ratio = 0.95; 95% confidence interval 0.90–0.98; P = 0.013). Conclusion. Progression was seen in 43% of AIS patients treated with the PB. Increase in flexibility was independently associated with a decreased risk of progression. Level of Evidence: 3