146. Reconstructive Approaches to Oncologic Upper and Lower Extremity Resection in Pediatric Populations: An Analysis of 400 Patients

PURPOSE: Tumors of the soft tissue and bone in the upper and lower extremities are more common in pediatric populations than the general adult population and require surgical resection or amputation in many cases. Existing literature of reconstructive approaches during these surgeries are largely limited to small sample sizes over long periods of time. This study employs a database with large geographic coverage to characterize reconstructive approaches to such cases and subsequent postoperative outcomes. METHODS: All oncologic upper and lower extremity resection or amputation cases were identified with CPT codes in the National Surgical Quality Improvement Program - Pediatric from 2013-2022. Reconstructive approaches for each case were characterized as primary closure, complex closure, skin graft or substitute, and/or flap. Flaps were further divided into pedicled flaps and free flaps. The main outcome of interest was the occurrence of at least one postoperative complication, including surgical site infection, dehiscence, venous thromboembolism, and reoperation or readmission. Predictors of flap reconstruction and predictors of postoperative complications were assessed with stepwise multivariable logistic regression (p<0.05). RESULTS: The final cohort comprised 400 oncologic upper and lower extremity cases. The average age was 11.0±4.9 years, and the average BMI was 20.4±6.1 kg/m2. Most tumors (308, 77.0%) presented in the lower extremity and in the proximal (221, 55.2%) anatomical regions (upper arm, elbow, thigh, and knee). The primary reconstructive approach was primary closure (258, 64.5%), followed by pedicled flaps (103, 25.8%), complex closure (37, 9.2%), skin grafts (25, 6.2%), and then free flaps (24, 6.0%). The rate of flap reconstruction increased from 5.0% in 2013-2016 to 36.5% in 2020-2022 (p<0.001). This proportion increased from 0.0% to 22.2% for upper extremity and from 8.2% to 38.8% for lower extremity (p<0.001). ASA class >2 (OR: 2.29, 95% CI: 1.28-4.12, p=0.0055), large tumor size as defined by CPT code (OR: 3.96, 95% CI: 1.48-10.6, p=0.0060), proximal region (OR: 0.38, 95% CI: 0.21-0.66, p<0.001), and soft tissue malignancy (OR: 0.08, 95% CI: 0.03-0.19, p<0.001) were significant predictors of flap reconstruction.81 (20.2%) patients experienced at least one postoperative complication with 17 (4.2%) cases of unplanned reoperation and 62 (15.5%) cases of unplanned readmission. A majority (68.2%) of readmissions related to the index diagnosis was due to adverse effects from chemotherapy. ASA class greater than 2 (OR: 2.13, 95% CI: 1.17-3.89, p=0.014) predicted higher likelihood of postoperative complications, whereas soft tissue malignancy (OR: 0.19, 95% CI: 0.10-0.38, p<0.001) predicted lower likelihood of complications compared to osseous malignancy. CONCLUSION: When characterized in a large national database, resection is associated with relatively favorable immediate postoperative outcomes. Although becoming more common, flap reconstruction of upper or lower extremity tumors is largely reserved for case with high oncologic burden and osseous tumors in the distal anatomical regions, including the tibia/fibula and forearm. Future work may consider further assessing the viability of flap reconstruction in other anatomical areas.