PROPOSE. Development and validation of a prediction model for shared decision making for patients with lumbar spinal stenosis.

Background: Decompression for lumbar spinal stenosis (LSS) is the most frequently performed spine surgery in Denmark. According to the Danish spine registry DaneSpine, at 1 year after surgery, about 75% of patients experiences considerable pain relief and around 66% improvement in quality of life. However, 25% do not improve very much. We have developed a predictive decision support tool, PROPOSE. It is intended to be used in the clinical conversation between healthcare providers and LSS patients as a shared decision-making aid presenting pros and cons of surgical intervention. This study presents the development and evaluation of PROPOSE in a clinical setting. Methods: For model development, 6.357 LSS patients enrolled in DaneSpine were identified. For model validation, predictor response and predicted outcome was collected via PROPOSE from 228 patients. Observed outcome at 1 year was retrieved from DaneSpine. All participants were treated at 3 Danish spine centers. The outcome measures presented are improvement in walking distance, the Oswestry Disability Index, EQ-5D-3L and leg/back pain on the Visual Analog Scale. Outcome variables were dichotomized into success (1) and failure (0). With the exception of walking distance, a success was defined as reaching minimal clinically important difference at 1-year follow-up. Models were trained using Multivariate Adaptive Regression Splines. Performance was assessed by inspecting confusion matrix, ROC curves and comparing GCV (generalized cross-validation) errors. Final performance of the models was evaluated on independent test data. Results: The walking distance model demonstrated excellent performance with an AUC of 0.88 and a Brier score of 0.14. The VAS leg pain model had the lowest discriminatory performance with an AUC of 0.67 and a Brier score of 0.22. Conclusions: PROPOSE works in a real-world clinical setting as a proof of concept and demonstrates acceptable performance. It may have the potential of aiding shared decision making.

Radiological Definitions of Sagittal Plane Segmental Instability in the Degenerative Lumbar Spine - A Systematic Review.

STUDY DESIGN: Systematic Review. OBJECTIVE: To collect and group definitions of segmental instability, reported in surgical studies of patients with lumbar spinal stenosis (LSS) and/or lumbar degenerative spondylolisthesis (LDS). To report the frequencies of these definitions. To report on imaging measurement thresholds for instability in patients and compare these to those reported in biomechanical studies and studies of spine healthy individuals.To report on studies that include a reliability study. METHODS: This review was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Studies eligible for inclusion were clinical and biomechanical studies on adult patients with LDS and/or LSS who underwent surgical treatment and had data on diagnostic imaging. A systematic literature search was conducted in relevant literature databases. Full text screening inclusion criteria was definition of segmental instability or any synonym. Two reviewers independently screened articles in a two-step process. Data synthesis presented by tabulate form and narrative synthesis. RESULTS: We included 118 studies for data extraction, 69% were surgical studies with decompression or fusion as interventions, 31% non-interventional studies. Grouping the definitions of segmental instability according similarities showed that 24% defined instability by dynamic sagittal translation, 26% dynamic translation and dynamic angulation, 8% used a narrative definition. Comparison showed that non-interventional studies with a healthy population more often had a narrative definition. CONCLUSION: Despite a reputation of non-consensus, segmental instability in the degenerative lumbar spine can radiologically be defined as > 3 mm dynamic sagittal translation.

Validating the predictive precision of the dialogue support tool on Danish patient cohorts.

Background: Despite advances in surgical techniques and diagnostics, some patients remain unsatisfied with the result following spine surgery. One way to improve patient satisfaction may be found in better alignment of expectations. Prognostic tools might prove useful in strengthening surgeon-patient communication prior to surgery. The purpose of this study is to assess the predictive capabilities of the Swedish based Dialogue Support (DS) tool for spine surgery on a Danish population. Methods: The study included the diagnoses lumbar disc herniation, lumbar spinal stenosis, and lumbar degenerative disc disease. A total of 5.954 patients were retrieved from the Danish national spine registry (DaneSpine). For each group, 200 random cases with complete preoperative and 1 year follow-up data were selected. Two outcome measures were used: Global assessment of pain (GA pain) and satisfaction with outcome. Predictions were produced by manual entry in the DS application. Goodness of fit tests were used to compare the predicted distribution of proportions with successful outcomes (GA pain) to the actual distribution in the three samples. Binomial tests were performed to evaluate the predicted proportion of satisfied patients. Furthermore, ROC-curves, calibration plots, and metrics were calculated to assess the predictive performance. Results: ROC curves showed comparable AUC values with the values reported by the developing authors of the DS from 0.62 to 0.73 (GA pain) and 0.64 to 0.70 (satisfaction with outcome). The calibration plots, however, revealed a low degree of concordance. For GA pain sensitivity varied from 92.4% to 99.3%, and specificity from 1.5% to 13.4%. For satisfaction, sensitivity varied from 97.1% to 99.2% and specificity from 0.0% to 2.9%. Conclusions: The predictive capabilities of the DS tool could not be generalized to the Danish sample cohorts. Further research on larger samples, provided full access to the underlying algorithms can be obtained, could produce a different result.

Applied Machine Learning for Spine Surgeons: Predicting Outcome for Patients Undergoing Treatment for Lumbar Disc Herniation Using PRO Data.

STUDY DESIGN: Retrospective/prospective study. OBJECTIVE: Models based on preoperative factors can predict patients' outcome at 1-year follow-up. This study measures the performance of several machine learning (ML) models and compares the results with conventional methods. METHODS: Inclusion criteria were patients who had lumbar disc herniation (LDH) surgery, identified in the Danish national registry for spine surgery. Initial training of models included 16 independent variables, including demographics and presurgical patient-reported measures. Patients were grouped by reaching minimal clinically important difference or not for EuroQol, Oswestry Disability Index, Visual Analog Scale (VAS) Leg, and VAS Back and by their ability to return to work at 1 year follow-up. Data were randomly split into training, validation, and test sets by 50%/35%/15%. Deep learning, decision trees, random forest, boosted trees, and support vector machines model were trained, and for comparison, multivariate adaptive regression splines (MARS) and logistic regression models were used. Model fit was evaluated by inspecting area under the curve curves and performance during validation. RESULTS: Seven models were arrived at. Classification errors were within ±1% to 4% SD across validation folds. ML did not yield superior performance compared with conventional models. MARS and deep learning performed consistently well. Discrepancy was greatest among VAS Leg models. CONCLUSIONS: Five predictive ML and 2 conventional models were developed, predicting improvement for LDH patients at the 1-year follow-up. We demonstrate that it is possible to build an ensemble of models with little effort as a starting point for further model optimization and selection.

Evolution and Advancement of Adult Spinal Deformity Research and Clinical Care: An Overview of the Scoli-RISK-1 Study.

STUDY DESIGN: Narrative review. OBJECTIVE: The prevalence of adult spinal deformity (ASD) has been cited anywhere between 2-32%, while the prevalence in the elderly population has been estimated at 68%. Neurologic complications following ASD surgery remains a concern. Previous literature reported incidence of neurologic complications varied between 1-10%, while non-neurologic complications reported were as high as 50%. To assess the incidence of neurologic deficits, complications, and outcomes following ASD surgery, an international group of spine deformity surgeons initiated a prospective, multicenter, international, observational study: Scoli-RISK-1. METHODS: Two hundred seventy-two patients were enrolled from 15 centers with ASD having primary or revision surgery with a major Cobb≥80°, revision including an osteotomy, and/or a complex 3-column osteotomy. Patients had lower extremity muscle strength (LEMS) exams performed preoperatively and at specific time points through 2-year follow-up. RESULTS: Preoperatively, 203 patients (74.9%) had no LEMS impairment (normal) and 68 (25.1%) had a LEMS of <50 (abnormal). Compared with baseline, 23.0% of all patients experienced a LEMS decline at discharge, with this rate decreasing to 17.1% at 6-weeks and to 9.9% at 6-months and remaining stable at 10.0% at 2-years. CONCLUSION: This study revealed that a decline in LEMS after complex ASD surgery is common and more frequent than previously reported. We identified such a decline in 23.0% of patients at discharge, with neurologic function recovering over time to a decline of 10.0% at 2-years postoperatively. The Scoli-RISK-1 study revealed valuable information regarding the incidence, natural history, and prognosis of neurologic and non-neurologic complications following ASD surgery and provides useful information for patient counseling.

Double-blind, randomized controlled trial of tranexamic acid in minor lumbar spine surgery: no effect on operative time, intraoperative blood loss, or complications.

OBJECTIVEThe purpose of this study was to investigate the effect of tranexamic acid (TXA) compared to placebo in low-risk adult patients undergoing elective minor lumbar spine surgery-specifically with respect to operative time, estimated blood loss, and complications. Studies have shown that TXA reduces blood loss during major spine surgery. There have been no previous studies on the effect of TXA in minor lumbar spine surgery in which these variables have been evaluated.METHODSThe authors enrolled patients with ASA grades 1 to 2 scheduled to undergo lumbar decompressive surgery at Middelfart Hospital into a double-blind, randomized, placebo-controlled, parallel-group study. Patients with thromboembolic disease, coagulopathy, hypersensitivity to TXA, or a history of convulsion were excluded. Patients were randomly assigned, in blocks of 10, to one of 2 groups, TXA or placebo. Anticoagulation therapy was discontinued 2-7 days preoperatively. Prior to the incision, patients received either a bolus of TXA (10 mg/kg) or an equivalent volume of saline solution (placebo). Independent t-tests were used to compare differences between the 2 groups, with statistical significance set at p < 0.05.RESULTSOf the 250 patients enrolled, 17 patients were excluded, leaving 233 cases for analysis (117 in the TXA group and 116 in the placebo group). The demographics of the 2 groups were similar, except for a higher proportion of women in the TXA group (TXA 50% vs placebo 32%, p = 0.017). There was no significant between-groups difference in operative time (49.53 ± 18.26 vs 54.74 ± 24.49 minutes for TXA and placebo, respectively; p = 0.108) or intraoperative blood loss (55.87 ± 48.48 vs 69.14 ± 83.47 ml for TXA and placebo, respectively; p = 0.702). Postoperative blood loss measured from drain output was 62% significantly lower in the TXA group (13.03 ± 21.82 ml) than in the placebo group (34.61 ± 44.38 ml) (p < 0.001). There was no significant difference in number of dural lesions or postoperative spinal epidural hematomas, and there were no thromboembolic events.CONCLUSIONSTranexamic acid did not have a statistically significant effect on operative time, intraoperative blood loss, or complications. This study gives no evidence to support the routine use of TXA during minor lumbar decompressive surgery.Clinical trial registration no.: NCT03714360 (clinicaltrials.gov).

Unilateral versus bilateral lower extremity motor deficit following complex adult spinal deformity surgery: is there a difference in recovery up to 2-year follow-up?

BACKGROUND CONTEXT: Scoli-RISK-1 is a multicenter prospective cohort designed to study neurologic outcomes following complex adult spinal deformity (ASD). The effect of unilateral versus bilateral postoperative motor deficits on the likelihood of long-term recovery has not been previously studied in this population. PURPOSE: To evaluate whether bilateral postoperative neurologic deficits have a worse recovery than unilateral deficits. STUDY DESIGN: Secondary analysis of a prospective, multicenter, international cohort study. METHODS: In a cohort of 272 patients, neurologic decline was defined as deterioration of the American Spinal Injury Association Lower Extremity Motor Scores (LEMS) following surgery. Patients with lower extremity neurologic decline were grouped into unilateral and bilateral cohorts. Differences in demographics, surgical variables, and patient outcome measures between the two cohorts were analyzed. RESULTS: A total of 265 patients had LEMS completed at discharge. Unilateral decline was seen in 32 patients (12%), while 29 (11%) had bilateral symptoms. At 2 years, there was no significant difference in either median LEMS (unilateral 50.0, interquartile range [IQR] 47.5-50.0; bilateral 50.0, IQR 48.0-50.0, p=.939) or change in LEMS from baseline (unilateral 0.0, IQR -1.0 to 0.0; bilateral 0.0, IQR -1.0 to 0.0, p=.920). In both groups, approximately two-thirds of patients saw recovery to at least their preoperative baseline by 2 years postoperatively (unilateral n=15, 63%; bilateral n=14, 67%). The mean Scoliosis Research Society-22R (SRS-22R) score at 2 years was 3.7±0.6 versus 3.2±0.6 (p=.009) for unilateral and bilateral groups, respectively. CONCLUSIONS: The prognosis for neurologic recovery of new motor deficits following complex adult spinal deformity is similar with both unilateral and bilateral weaknesses. Despite similar rates of neurologic recovery, patient reported outcomes for those with bilateral motor decline measured by SRS-22R are worse at 2 years after surgery.

Management of Unstable Fracture-Dislocations of the Spine in Polytrauma Patients.

A multidisciplinary and systematic approach is required for the treatment of polytrauma patients with a thoracolumbar fracture-dislocation to provide timely care and prevent iatrogenic injury. Thoracolumbar fracture-dislocations frequently occur in patients who sustain a high-energy mechanism of injury; therefore, they are associated with other orthopaedic and visceral injuries that need to be identified via a systematic protocol. Orthopaedic surgeons must obtain a thorough patient history, perform an appropriate physical examination, and obtain adequate imaging studies to expeditiously treat polytrauma patients with a thoracolumbar fracture-dislocation.

Minimum Detectable Measurement Difference for Health-Related Quality of Life Measures Varies With Age and Disability in Adult Spinal Deformity: Implications for Calculating Minimal Clinically Important Difference.

STUDY DESIGN: Retrospective cohort. OBJECTIVE: To investigate the minimum detectable measurement difference (MDMD) in the Scoliosis Research Society-22r (SRS-22r) outcomes instrument in adult spinal deformity (ASD) and to evaluate the effect of baseline data on measurable difference. SUMMARY OF BACKGROUND DATA: The minimum clinically important difference (MCID) is the smallest, clinically relevant change observed and has been proposed for the SRS-22r instrument in ASD as 0.4. The MCID must be greater than the MDMD to be useful. The MDMD for the SRS-22r has not been calculated, nor have the effect of patient baseline values on MDMD. METHODS: A prospective observation cohort was queried for patients treated both operatively and nonoperatively for ASD. Patients with baseline and 1-year, 2-year follow-up SRS-22r data were included in the analysis. The MDMD was calculated using classical test theory and item-response theory methods. Effect size and standardized response means were calculated. The effect of baseline data values was evaluated for MDMD. RESULTS: A total 839 Patients were eligible for cohort inclusion with 428 (51%) eligible for analysis with complete data. MDMD for Pain (0.6) and Self-Image (0.5) were greater than 0.4. MDMD varied with age (highest for the youngest patients) and with disability (highest for SF-36 Physical Component Summary <28.6). MDMD was less than 0.4 for Activity (0.3), Mental Health (0.3), and Total Score (0.2). Gender and mental health did not affect MDMD for the SRS-22r instrument. CONCLUSION: An MCID of 0.4 for the SRS-22r total score and domain scores may not be an appropriate value as the calculated MDMD is greater than 0.4 for both the Pain and Self-Image subscores. The MDMD for the SRS-22r instrument varied with age and baseline disability, making the assessment of clinically significant change more difficult using this tool. The MCID must be considered in the setting of the MDMD for instruments used to assess outcomes in ASD. LEVEL OF EVIDENCE: 3.

The importance and impact of patients' health literacy on low back pain management: a systematic review of literature.

BACKGROUND CONTEXT: Health literacy (HL) and the overall ability of patients to seek, understand, and apply health information play an important role in the management of chronic pain conditions. Awareness of how patients' HL skills influence their pain experience and how their ability to understand the treatment regimen and to manage chronic pain may allow physicians to adjust clinical treatment accordingly. Despite the prevalence and the substantial economic impact of chronic low back pain (LBP), little is known about the relationship between HL and the treatment and management of this common disease entity. PURPOSE: The purpose of this systematic review of published research was to examine the importance and the implications of HL in the treatment and management of LBP. STUDY DESIGN AND METHODS: A literature search was performed in Web of Science, PubMed, Cumulative Index to Nursing and Allied Health Literature, and PsychInfo using medical subject heading (MeSH) terms related to LBP, HL, and patient education, which yielded only three studies that directly addressed HL among patients suffering from LBP. RESULTS: We identified only a limited number of studies that focused specifically on HL in the LBP population that were included in this review. The majority of studies excluded from this review focused on patient levels of educational attainment and patient education programs without addressing patients' HL levels and their impact on adherence to educational programs, self-care management, and rehabilitation, among other factors. The three studies that are critically reviewed in this review either use a direct measure of HL or make an effort to address HL in their programs. All three studies emphasize the importance of considering the HL of patients in the treatment and management of LBP. CONCLUSIONS: Building on these studies and the narrative review of other relevant literature, we identified significant gaps in current research addressing HL in the treatment and management of LBP. We developed recommendations for future research based on an assessment of strengths and limitations of available evidence-based studies.

Cell Saver for Adult Spinal Deformity Surgery Reduces Cost.

STUDY DESIGN: Retrospective cohort. OBJECTIVES: To determine if the use of cell saver reduces overall blood costs in adult spinal deformity (ASD) surgery. SUMMARY OF BACKGROUND DATA: Recent studies have questioned the clinical value of cell saver during spine procedures. METHODS: ASD patients enrolled in a prospective, multicenter surgical database who had complete preoperative and surgical data were identified. Patients were stratified into (1) cell saver available during surgery, but no intraoperative autologous infusion (No Infusion group), or (2) cell saver available and received autologous infusion (Infusion group). RESULTS: There were 427 patients in the Infusion group and 153 in the No infusion group. Patients in both groups had similar demographics. Mean autologous infusion volume was 698 mL. The Infusion group had a higher percentage of EBL relative to the estimated blood volume (42.2%) than the No Infusion group (19.6%, p < .000). Allogeneic transfusion was more common in the Infusion group (255/427, 60%) than the No Infusion group (67/153, 44%, p = .001). The number of allogeneic blood units transfused was also higher in the Infusion group (2.4) than the No Infusion group (1.7, p = .009). Total blood costs ranged from $396 to $2,146 in the No Infusion group and from $1,262 to $5,088 in the Infusion group. If the cost of cell saver blood was transformed into costs of allogeneic blood, total blood costs for the Infusion group would range from $840 to $5,418. Thus, cell saver use yielded a mean cost savings ranging from $330 to $422 (allogeneic blood averted). Linear regression showed that after an EBL of 614 mL, cell saver becomes cost-efficient. CONCLUSION: Compared to transfusing allogeneic blood, cell saver autologous infusion did not reduce the proportion or the volume of allogeneic transfusion for patients undergoing surgery for adult spinal deformity. The use of cell saver becomes cost-efficient above an EBL of 614 mL, producing a cost savings of $330 to $422. LEVEL OF EVIDENCE: Level III.

Impact of cost valuation on cost-effectiveness in adult spine deformity surgery.

BACKGROUND CONTEXT: Over the past decade, the number of adult spinal deformity (ASD) surgeries has more than doubled in the United States. The complex surgeries needed to manage ASD are associated with significant resource utilization and high cost, making them a primary target for increased scrutiny. Accordingly, it is important to not only demonstrate value in ASD surgery as clinical effectiveness but also to translate outcome assessment to cost-effectiveness. PURPOSE: To compare the difference between Medicare allowable rates and the actual, direct hospital costs for ASD surgeries. STUDY DESIGN: Longitudinal cohort. PATIENT SAMPLE: Consecutive patients enrolled in an ASD database from a single institution. OUTCOME MEASURES: Short Form (SF)-6D. METHODS: Consecutive patients enrolled in an ASD database from a single institution from 2008 to 2013 were identified. Direct hospital costs were collected from hospital administrative records for the entire inpatient episode of surgical care. Medicare allowable rates were calculated for the same inpatient stays using the year-appropriate Center for Medicare-Medicaid Services Inpatient Pricer Payment System Tool. The SF-6D, a utility index derived from the SF-36v1, was used to determine quality-adjusted life years (QALY). Costs and QALYs were discounted at 3.5% annually. RESULTS: Of 580 surgical ASD patients eligible for 2-year follow up, 346 (60%) had complete baseline and 2-year data, and 60 were Medicare beneficiaries comprising the cohort for the present study. Mean SF-6D gained is 0.10 during year 1 after surgery and 0.02 at year 2, resulting in a cumulative SF-6D gain of 0.12 over 2 years. Mean Medicare allowable rate over the 2 years is $82,050 (range $42,383 to $220,749) and mean direct cost is $99,114 (range $28,447 to $217,717). Mean cost per QALY over 2 years is $683,750 using Medicare allowable rates and $825,950 using direct costs. This difference of $17,181 between the 2 cost calculation represents a 17% difference, which was statistically significant (p<.001). CONCLUSIONS: There is a significant difference in direct hospital costs versus Medicare allowable rates in ASD surgery and in turn, there is a similar difference in the cost per QALY calculation. Utilizing Medicare allowable rates not only underestimates (17%) the cost of ASD surgery, but it also creates inaccurate and unrealistic expectations for researchers and policymakers.

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. Patient's 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.

Patient satisfaction after surgical correction of adolescent idiopathic scoliosis.

STUDY DESIGN: Longitudinal cohort. OBJECTIVE: The purpose of this study is to evaluate the relationship between change in SRS-22 domain scores and satisfaction with management in patients who underwent surgical correction for adolescent idiopathic scoliosis (AIS). SUMMARY OF BACKGROUND DATA: The Scoliosis Research Society-22 (SRS-22) is a widely used instrument to measure clinical outcomes in patients with scoliosis. The relationship between patient satisfaction and changes in domain scores in the SRS-22 has not been previously reported. METHODS: This is a longitudinal cohort of 745 patients with AIS who underwent surgical correction and had completed SRS-22 preoperative and 2 years postoperative. Patients who had a previous spine surgery were excluded. Wilcoxon tests were used to compare preop and 2-year postop scores. Spearman correlations were used to evaluate associations between change in SRS-22 domain scores from preoperative to 2 years postoperative and the 2-year SRS Satisfaction score. RESULTS: There were 622 females and 123 males with a mean age of 14.2 years and a mean Cobb angle of 54°. There was a statistically significant difference between paired preoperative and 2-year postoperative SRS domain scores. Spearman correlations between the change in SRS domain scores and the SRS Satisfaction score at 2 years postoperative were statistically significant but were low to moderate: Appearance = 0.284, Activity = 0.172, Pain = 0.260, Mental = 0.202, and Total = 0.398. CONCLUSION: Although there is a statistically significant change in all the SRS domain scores from preoperative to 2 years postsurgical correction of AIS, there was low to moderate associations between the change in any of the domain scores and patient satisfaction with treatment. This may be attributable to the prominent ceiling effect in the Satisfaction domain, or the lack of responsiveness of the SRS-22 to measure clinically relevant changes in activity, pain and mental health 2 years after correction of scoliosis in the adolescent population.

Platelet gel (AGF) fails to increase fusion rates in instrumented posterolateral fusions.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To determine the effect on fusion of adding platelet gel to autologous iliac crest graft. SUMMARY OF BACKGROUND DATA: Platelet gel is an osteoinductive material prepared by ultra-concentration of platelets and contains multiple growth factors. Proprietary commercial methods are available for harvesting autologous platelet gel concentrates for use as graft supplement in spine fusions. METHODS: We reviewed 76 consecutive patients who underwent instrumented posterolateral lumbar fusion with autologous iliac crest bone graft mixed with autologous growth factor (AGF). A control group was randomly selected from patients who underwent instrumented posterolateral lumbar fusion with autologous bone graft alone. The groups were matched for age, sex, smoking history, and number of levels fused. Demographic, surgical, and clinical data were collected from medical records. Diagnosis of nonunion was based on exploration during revision surgery or evidence of nonunion on computerized tomography. The Fisher exact test was used to compare fusion rates. RESULTS: In both groups, mean age was 50 years, and 24% were smokers. The nonunion rate was 25% in the AGF group and 17% in the control group. This difference was not statistically significant (P = 0.18). CONCLUSIONS: Platelet gel preparation requires blood draws from the patient. This procedure adds to the risk and cost of surgery. The technique for AGF harvest evaluated in this study provides the highest concentration of platelets among the commercially available methods. Despite this, we showed that platelet gel failed to enhance fusion rate when added to autograft in patients undergoing instrumented posterolateral spinal fusion. The authors do not recommend the use of platelet gel to supplement autologous bone graft during instrumented posterolateral spinal fusion.