Kelly R. Bratcher

The Effect of Obesity on Clinical Outcomes After Lumbar Fusion

Study Design. Retrospective cohort analysis. Objective. To investigate and compare back and leg pain, and health-related quality of life measures in obese patients undergoing lumbar spine fusion, and to compare the results to nonobese patients. Summary of Background Data. Obesity is a growing healthcare crisis in the United States and an increasing number of patients undergoing spinal surgery are obese. Obesity is also associated with low back pain. Some obese patients with significant structural spine problems may be dismissed as having their pain only coming from their weight. We compared patient outcomes in obese and nonobese patients undergoing lumbar fusion surgery. Methods. We retrospectively reviewed a single-center patient database of patients undergoing lumbar fusion and identified 270 patients with greater than 2-year outcome data. Body mass index (BMI) was calculated and patients were classified as obese (BMI ≥ 30) or nonobese (BMI < 30). All patients completed Oswestry Disability Index (ODI), Short Form (SF)-36 questionnaires, and back and leg pain numerical rating scores before surgery and at 2 years. We compared clinical outcomes and complication rates in the 2 groups. Results. The overall study group consisted of 109 obese patients and 161 nonobese patients. Both the obese and nonobese patients demonstrated significant improvements in back pain, leg pain, SF-36 physical composite summary (PCS), and ODI scores (P < 0.001) at 2-year follow-up compared with baseline. There was no significant difference in the mean improvements seen in obese patients compared with nonobese patients with respect to back pain, leg pain, or SF-36 PCS or ODI scores. Both SF-36 PCS (P = 0.037) and ODI score (P = 0.028) at 2-year follow-up were better in the nonobese patients compared with the obese patients. Overall complication rates were slightly higher in the obese group (P = 0.045), predominantly because of wound-related complications. Conclusion. Obese patients undergoing lumbar fusion achieve similar benefits to nonobese patients. Wound-related complications are more common in obese patients. Obese patients with otherwise good indications for lumbar fusion should not be denied this procedure because of their weight.

Spinal appearance questionnaire: factor analysis, scoring, reliability, and validity testing.

Study Design. Cross sectional. Objective. This study presents the factor analysis of the Spinal Appearance Questionnaire (SAQ) and its psychometric properties. Summary of Background Data. Although the SAQ has been administered to a large sample of patients with adolescent idiopathic scoliosis (AIS) treated surgically, its psychometric properties have not been fully evaluated. This study presents the factor analysis and scoring of the SAQ and evaluates its psychometric properties. Methods. The SAQ and the Scoliosis Research Society-22 (SRS-22) were administered to AIS patients who were being observed, braced or scheduled for surgery. Standard demographic data and radiographic measures including Lenke type and curve magnitude were also collected. Results. Of the 1802 patients, 83% were female; with a mean age of 14.8 years and mean initial Cobb angle of 55.8° (range, 0°–123°). From the 32 items of the SAQ, 15 loaded on two factors with consistent and significant correlations across all Lenke types. There is an Appearance (items 1–10) and an Expectations factor (items 12–15). Responses are summed giving a range of 5 to 50 for the Appearance domain and 5 to 20 for the Expectations domain. The Cronbachs &agr; was 0.88 for both domains and Total score with a test–retest reliability of 0.81 for Appearance and 0.91 for Expectations. Correlations with major curve magnitude were higher for the SAQ Appearance and SAQ Total scores compared to correlations between the SRS Appearance and SRS Total scores. The SAQ and SRS-22 Scores were statistically significantly different in patients who were scheduled for surgery compared to those who were observed or braced. Conclusion. The SAQ is a valid measure of self-image in patients with AIS with greater correlation to curve magnitude than SRS Appearance and Total score. It also discriminates between patients who require surgery from those who do not.

Differentiating minimum clinically important difference for primary and revision lumbar fusion surgeries.

OBJECT Previous studies have reported on the minimum clinically important difference (MCID), a threshold of improvement that is clinically relevant for lumbar degenerative disorders. Recent studies have shown that pre- and postoperative health-related quality of life (HRQOL) measures vary among patients with different diagnostic etiologies. There is also concern that a patients previous care experience may affect his or her perception of clinical improvement. This study determined if MCID values for the Oswestry Disability Index (ODI), 36-Item Short-Form Health Survey (SF-36), and back and leg pain are different between patients undergoing primary or revision lumbar fusion. METHODS Prospectively collected preoperative and 1-year postoperative patient-reported HRQOLs, including the ODI, SF-36 physical component summary (PCS), and numeric rating scales (0-10) for back and leg pain, in patients undergoing lumbar spine fusion were analyzed. Patients were grouped into either the primary surgery or revision group. As the most widely accepted MCID values were calculated from the minimum detectable change, this method was used to determine the MCID. RESULTS A total of 722 patients underwent primary procedures and 333 patients underwent revisions. There was no statistically significant difference in demographics between the groups. Each group had a statistically significant improvement at 1 year postoperatively compared with baseline. The minimum detectable change-derived MCID values for the primary group were 1.16 for back pain, 1.36 for leg pain, 12.40 for ODI, and 5.21 for SF-36 PCS. The MCID values for the revision group were 1.21 for back pain, 1.28 for leg pain, 11.79 for ODI, and 4.90 for SF-36 PCS. These values are very similar to those previously reported in the literature. CONCLUSIONS The MCID values were similar for the revision and primary lumbar fusion groups, even when subgroup analysis was done for different diagnostic etiologies, simplifying interpretation of clinical improvement. The results of this study further validate the use of patient-reported HRQOLs to measure clinical effectiveness, as a patients previous experience with care does not seem to substantially alter an individuals perception of clinical improvement.

Does Fusion Status Correlate with Patient Outcomes in Lumbar Spinal Fusion

Study Design. Prospective cohort. Objectives. The purpose of this study is to examine the relationship between radiographic fusion and patient-reported health-related quality of life (HRQOL) measures in patients undergoing instrumented posterolateral lumbar fusion. Summary of Background Data. Previous studies have shown that a solid fusion does not always produce clinical success. However, these studies did not use validated patient-reported HRQOL measures. Methods. One hundred ninety-three patients who underwent instrumented posterolateral fusion with complete preoperative and 2-year HRQOL measures and a fine-cut computed tomographic (CT) scan with reconstructions done at 2 years after surgery specifically done to assess fusion status were identified. HRQOL measures included the Oswestry Disability Index (ODI), the Short Form-36 and back and leg pain numerical rating scales. The percentage of patients reaching the minimum clinically important difference and substantial clinical benefit for ODI and Short Form-36 were also calculated. CT scans were graded as fused or not by three independent reviewers. Comparisons were made in outcomes measures between the patients with solid fusions and those judged not to have a solid radiographic fusion. Results. There were 124 women and 69 men with an average age of 63 years. Patients judged to have a solid fusion demonstrated a better ODI score at 2 years than those who were not solidly fused (P = 0.023). There was a trend toward greater improvement in mean ODI score in those with a solid fusion (P = 0.074). A statistically greater number of patients who had a solid fusion (111 of 171, 65%) achieved the minimum clinically important difference for ODI than those who did not achieve a solid fusion (7 of 22, 32%) (P = 0.004). Conclusion. A greater proportion of patients achieved clinically relevant improvements in low back specific quality-of-life measures when they had achieved a solid fusion than patients who did not have a solid fusion. Although radiographic fusion may not be the true measure of clinical success, this study suggests that solid arthrodesis contributes to clinical outcome and is an important goal of fusion surgery.

Predictive factors for the use of autologous cell saver transfusion in lumbar spinal surgery.

Study Design. Retrospective review. Objective. To identify risk factors for cell saver transfusion in lumbar spinal surgery and determine if cell saver transfusions affected intraoperative or postoperative transfusion rates. Summary of Background Data. Cell saver has been used to minimize allogeneic blood transfusion in lumbar spinal surgery. Conflicting reports exist, which call into question the efficacy of cell saver use. Methods. We reviewed medical records of randomly selected patients who underwent posterolateral fusion with or without transforaminal interbody fusion from July 2010 to June 2011. Transfusion rates and transfusion-related complications were determined. Binary logistic regression was performed to identify risk factors for use of autologous cell saver transfusion. Results. There were 178 females and 107 males, with a mean age of 57.2 years. Of the 285 cases, 39 had no cell saver available, 147 had cell saver available but no autologous blood was recovered or transfused and 99 had an autologous cell saver transfusion. Patients who had cell saver transfusion had a higher rate of intraoperative allogeneic blood transfusion (52%) compared with those who did not (22%). There was no significant difference in the rate of postoperative transfusions or transfusion-related reactions between patients who did and did not have cell saver transfusion. Patients age, smoking status, American Society of Anesthesiologists grade, use of anticoagulants preoperatively, primary or revision surgery, iliac crest bone graft harvest, anesthesiologist, or surgeon had no significant effect on cell saver infusion. Body mass index (odds ratio [OR] = 1.06), number of posterolateral fusion levels fused (OR = 2.50), and number of transforaminal interbody fusions performed (OR = 2.41) were independent risk factors for the use of autologous cell saver transfusion. Conclusion. Body mass index, multi-level fusion and transforaminal interbody fusion result in increased use of autologous cell saver transfusion in lumbar spinal surgery. Use of autologous cell saver transfusion did not reduce the requirement for intraoperative or postoperative allogeneic blood transfusion. Level of Evidence: 2

Blood salvage produces higher total blood product costs in single-level lumbar spine surgery.

Study Design. Retrospective review. Objective. To determine the incremental cost-effectiveness of cell saver for single-level posterior lumbar decompression and fusion (PLDF). Summary of Background Data. Intraoperative cell salvage is used during surgery to reduce the need for perioperative allogeneic blood transfusion. Although the use of cell saver may be beneficial in certain circumstances, its utility has not been clearly established for the common procedure of an adult single-level PLDF. Methods. Randomly selected adult patients treated with a single-level PLDF between July 2010 and June 2011 at a single institution were identified. Patients who had a combined anterior and posterior approach were excluded. The final study sample for analysis consisted of 180 patients. Hospital records were reviewed to determine whether: (1) cell saver was available during surgery, (2) recovered autologous blood was infused, and (3) the patient received intra- or postoperative allogeneic transfusions. Estimated blood loss, levels fused, volume(s) transfused, and all related complications were recorded. Costs included the cost of allogeneic blood transfusion, setting up the cell saver recovery system, and infusing autologous blood from cell saver, whereas effectiveness measures were allogeneic blood transfusions averted and quality adjusted life years. Results. The incremental cost-effectiveness ratio was

Changes in the Oswestry Disability Index that predict improvement after lumbar fusion: Clinical article

55,538 per allogeneic transfusion averted, with a decrease in the transfusion rate from 40.0% to 38.7% associated with the cell saver approach. This translated into an incremental cost-effectiveness ratio of

Outcomes and revision rates in normal, overweight, and obese patients 5 years after lumbar fusion.

5,555,380 per quality adjusted life years gained, which is well above the threshold for an intervention to be considered cost-effective (

Estimating EQ-5D values from the Oswestry Disability Index and numeric rating scales for back and leg pain.

100,000 per quality adjusted life years gained). Conclusion. The use of cell saver during a single-level PLDF does not significantly reduce the need for allogeneic blood transfusion and is not cost-effective. The high cost of cell saver in combination with the low complication rate of allogeneic blood transfusion, suggest that cell saver should not be used for single-level PLDF. Further studies are needed to evaluate the necessity for cell saver among other types of spinal surgery.

Inter- and Intraobserver Reliability in Radiographic Assessment of Degenerative Disk Disease

OBJECT Clinical studies use both disease-specific and generic health outcomes measures. Disease-specific measures focus on health domains most relevant to the clinical population, while generic measures assess overall health-related quality of life. There is little information about which domains of the Oswestry Disability Index (ODI) are most important in determining improvement in overall health-related quality of life, as measured by the 36-Item Short Form Health Survey (SF-36), after lumbar spinal fusion. The objective of the study is to determine which clinical elements assessed by the ODI most influence improvement of overall health-related quality of life. METHODS A single tertiary spine center database was used to identify patients undergoing lumbar fusion for standard degenerative indications. Patients with complete preoperative and 2-year outcomes measures were included. Pearson correlation was used to assess the relationship between improvement in each item of the ODI with improvement in the SF-36 physical component summary (PCS) score, as well as achievement of the SF-36 PCS minimum clinically important difference (MCID). Multivariate regression modeling was used to examine which items of the ODI best predicted achievement for the SF-36 PCS MCID. The effect size and standardized response mean were calculated for each of the items of the ODI. RESULTS A total of 1104 patients met inclusion criteria (674 female and 430 male patients). The mean age at surgery was 57 years. All items of the ODI showed significant correlations with the change in SF-36 PCS score and achievement of MCID for the SF-36 PCS, but only pain intensity, walking, and social life had r values > 0.4 reflecting moderate correlation. These 3 variables were also the dimensions that were independent predictors of the SF-36 PCS, and they were the only dimensions that had effect sizes and standardized response means that were moderate to large. CONCLUSIONS Of the health dimensions measured by the ODI, pain intensity, walking, and social life best predicted improvement in overall health-related quality of life, as measured using the SF-36 PCS.