Comparison of the Coagulation Profile of Adolescent Idiopathic Scoliosis Patients Undergoing Posterior Spinal Fusion With and Without Tranexamic Acid.

STUDY DESIGN: Prospective, observational cohort study. OBJECTIVE: To improve the understanding of coagulation and bleeding mechanisms during spinal deformity surgery. SUMMARY OF BACKGROUND DATA: Fibrinolysis is the mechanism of bleeding for adolescent idiopathic scoliosis undergoing posterior spinal fusion. Antifibrinolytics have become popular; however, literature to support their use remains mixed. The mechanism of action has not been demonstrated. METHODS: The coagulation profile of 88 adolescent idiopathic scoliosis patients undergoing posterior spinal fusion was analyzed. Standard coagulation laboratory investigations and thromboelastograms were drawn hourly through the case. Fifty-eight patients received no antifibrinolytic, whereas 30 patients received tranexamic acid by standardized protocol. The coagulation parameters, estimated blood loss, and transfusion requirements were compared in the two groups. RESULTS: The two cohorts had no differences in demographic or surgical characteristics. Mean age was 13.6 years, 83% were female, a mean of 11.1 levels were fused, and the mean duration of surgery was 209 minutes. The tranexamic acid cohort did not demonstrate a decrease in blood loss. The transfusion rate, however, dropped from 47% in the non-tranexamic acid cohort to 23% in the tranexamic acid cohort (p = .03). Standard coagulation parameters did not differ between the groups. Fibrinolysis was diminished in the tranexamic acid cohort as measured by a Fibrinolysis score (mean maximum value 2.0 without tranexamic acid vs. 0.7 with tranexamic acid, p < .0001) and the lysis percent at 30 minutes by thromboelastogram (elevated to 3.9% without tranexamic acid vs. 1.2% with tranexamic acid at the 3-hour mark, p = .05). CONCLUSIONS: This study provides confirmation of antifibrinolytic activity during posterior spinal fusion for adolescent idiopathic scoliosis. The presented data of fibrinolysis are proposed as standard measurements for future work on controlling blood loss during scoliosis surgery. LEVEL OF EVIDENCE: Level 2, prospective comparative study.

SRS-22r Scores in Nonoperated Adolescent Idiopathic Scoliosis Patients With Curves Greater Than Forty Degrees.

STUDY DESIGN: Case control comparative series. OBJECTIVE: Describe surgical range adolescent idiopathic scoliosis (AIS) patients electing to forgo surgery and compare health-related quality-of-life outcomes to a similar cohort of operated AIS patients by the same single surgeon. SUMMARY OF BACKGROUND DATA: No data have been published either documenting SRS-22r scores of nonoperated patients with curves ≥40° or comparing these scores to a demographically similar operated cohort. METHODS: Individuals with curves ≥40°, age ≥18 years, and electing to forgo surgery were identified. All patients completed an SRS-22r questionnaire. This nonoperated cohort's SRS-22r scores were compared to those of a large demographically similar cohort operated by the same surgeon. Group differences between the SRS-22r scores were evaluated by comparing these to published Minimal Clinically Important Differences (MCID) for the SRS-22r. RESULTS: One hundred ninety subjects with nonoperated curves were compared to 166 individuals who underwent surgery. The nonoperated cohort averaged 23.5 years of age, averaged 7.7 years since curve reached 40°, and had an average 50° Cobb angle at last follow-up. No statistical significant differences were found between the groups on the Pain, Function, or Mental Health domains of the SRS-22r. Statistically significant differences in favor of the operative cohort were found for self-image, satisfaction, and total score. The observed group differences did not meet the established thresholds for minimal clinically important differences in any of the domain scores, the average total score, or raw scores. CONCLUSION: There are no meaningful clinically significant differences in SRS-22r scores at average 8-year follow-up between AIS patients with curves ≥40° treated with or without surgery. These data in conjunction with an absence of long-term evidence of serious medical consequences with nonsurgical management of curves ≥40° should encourage surgeons to reevaluate the benefits of routine surgical care. LEVEL OF EVIDENCE: 3.

Coagulation Profile of Patients with Adolescent Idiopathic Scoliosis Undergoing Posterior Spinal Fusion.

BACKGROUND: Blood loss and transfusion requirements during posterior spinal fusion for adolescent idiopathic scoliosis remain a concern. The mechanism of bleeding in these patients is poorly characterized. Thromboelastography is a comprehensive test of a patient's coagulation system commonly used in cardiac surgical procedures. It has not been well studied for use in patients with adolescent idiopathic scoliosis. METHODS: A prospective, observational study of the coagulation profile of patients with adolescent idiopathic scoliosis undergoing posterior spinal fusion is presented. Healthy patients with adolescent idiopathic scoliosis without a bleeding abnormality were analyzed during posterior spinal fusion. Standard coagulation laboratory and thromboelastogram measures were obtained at the time of the incision and at 1-hour intervals during the surgical procedure. Laboratory values were analyzed in relation to outcomes such as bleeding, transfusion, and a fibrinolysis score. RESULTS: Fifty-eight patients were observed. Eighty-one percent of patients were female, the mean age was 13.5 years, a mean of 11.1 levels were fused, the median estimated blood loss was 645 mL, and 47% of patients received blood products. Overall, laboratory values remained stable throughout the surgical procedure. Mild increases in prothrombin time and partial thromboplastin time were observed, and platelets remained stable. From thromboelastogram analysis, an acceleration of clot formation (decreased reaction time) and a slight increase in clot lysis (increased lysis percentage at 30 minutes) were observed. A fibrinolysis score compiled from the presence of fibrin degradation products, the presence of D-dimers, and increased prothrombin time rose steadily over surgical time. The fibrinolysis score was predictive of both transfusion and greater estimated blood loss per level. CONCLUSIONS: The stress of posterior spinal fusion induces a hypercoagulable state in patients with adolescent idiopathic scoliosis. Over the first 2 hours of a surgical procedure, varying degrees of fibrinolysis develop. Platelets and coagulation factors are not depleted. Our data support the use of antifibrinolytic therapy for patients with adolescent idiopathic scoliosis.

Converting Scoliosis Research Society-24 to Scoliosis Research Society-22r in a Surgical-Range, Medical/Interventional Adolescent Idiopathic Scoliosis Patient Cohort.

STUDY DESIGN: Prospective questionnaire administration study. OBJECTIVES: To assess the ability to translate total and domain scores from Scoliosis Research Society (SRS)-24 to SRS-22r in a surgical-range, medical/interventional adolescent idiopathic scoliosis (AIS) patient population. SUMMARY OF BACKGROUND DATA: Conversion of SRS-24 to SRS-22r is demonstrated in an operative cohort of patients with AIS, but not in a medical/interventional patient population. METHODS: We simultaneously administered SRS-24 and SRS-22r questionnaires to 75 surgical-range, medical/interventional AIS patients and compared them. We performed analysis by regression modeling to produce conversion equations from SRS-24 to SRS-22r. RESULTS: The total SRS-24 score for these medical/interventional AIS patients was 92.5 ± 9.45 (mean, 3.9 ± 0.39), and the total SRS-22r score was 93.5 ± 9.63 (mean, 4.3 ± 0.44). The correlation between these 2 groups was fair (R2 = 0.77) and improved to good when mental health or recall questions were removed. The correlation was also fair for total pain domains (R2 = 0.73). However, there was poor correlation for general self-image (R2 = 0.6) and unacceptable for post-treatment self-image (R2 = 0.01), general function (R2 = 0.52), activity function (R2 = 0.56), and satisfaction (R2 = 0.53). Compared with a published population of operative AIS patients, R2 values for total SRS-24 scores, pain, general self-image, activity function, and satisfaction were similar (p > .05). The R2 values for general function and combined general and activity function were significantly different between the operative and medical/interventional cohorts. CONCLUSIONS: Scoliosis Research Society-24 can be converted to SRS-22r scores with fair accuracy in the surgical-range, medical/interventional AIS patient population for total score, and total pain domains. The SRS-24 translates unacceptably to the SRS-22r in self-image, function, and satisfaction domains. The SRS-24 to SRS-22r conversion equations are similar to operative AIS patients, except for the function domain. Caution should be used when interpreting results based on translation of SRS-24 to SRS-22r values.