Virtual surgical planning and 3D printing in pediatric musculoskeletal oncological resections: a proof-of-concept description.

BACKGROUND AND OBJECTIVES: Patient-specific models may have a role in planning and executing complex surgical procedures. However, creating patient-specific models with virtual surgical planning (VSP) has many steps, from initial imaging to finally realizing the three-dimensional printed model (3DPM). This manuscript evaluated the feasibility and potential benefits of multimodal imaging and geometric VSP and 3DPM in pediatric orthopedic tumor resection and reconstruction. MATERIALS AND METHODS: Twelve children with Ewing's sarcoma, osteosarcoma, or chondrosarcoma were studied. Computed tomography (CT) and contrast-enhanced magnetic resonance imaging (MRI) were acquired as the standard-of-care. Bony and soft tissue components of the tumor and the adjacent bone were segmented to create a computer-generated 3D model of the region. VSP used the computer-generated 3D model. The Objet350 Stratasys™ polyjet printer printed the final physical model used for pre-surgical planning, intraoperative reference, and patient education. Clinical impact, the utility of the model, and its geometric accuracy were assessed. RESULTS: Subjectively, using the patient-specific model assisted in preoperative planning and intra-operative execution of the surgical plan. The mean difference between the models and the surgical resection was -0.09 mm (range: -0.29-0.45 mm). Pearson's correlation coefficient (r) of the cross-sectional area was -0.9994, linear regression r2 = 0.9989, and the Bland Altman plot at 95% confidence interval showed all data within boundaries. CONCLUSION: We studied the geometric accuracy, utility and clinical impact of VSP and 3DPM produced from multi-modal imaging studies and concluded 3DPM accurately represented the patients' tumor and proved very useful to the surgeon in both the preoperative surgical planning, patient and family education and operative phases. Future studies will be planned to evaluate surgery procedure duration and other outcomes.

Utility of 45S5 Bioactive Glass As Bone Graft Substitute for Cavitary Defects in Pediatric Bone Tumors: A Preliminary Study.

BACKGROUND: Bioactive glass has become an increasingly used treatment of cavitary bone defects in a number of orthopaedic applications. The purpose of this study was to evaluate the clinical and radiographic outcomes of bioactive glass used for benign cavitary pediatric bone tumors. A specific focus was on radiographic filling of defects and occurrence of complications by tumor class. METHODS: A single institution retrospective study was performed, which entailed review of the clinical and radiographic data of 21 patients who underwent surgical curettage and grafting of benign or low-grade malignant bone tumors from 2018 to 2020. In all the cases, 45S5 bioactive glass (Fibergraft; Prosidyan, New Providence, NJ) was used to fill the bone defects. For each patient, data on demographic, preoperative diagnosis, defect size, time to mobilization, radiographic filling grade, pain, and complications were obtained. The Wilcoxon-Mann-Whitney test and Kaplan-Meier survival analysis were used for comparisons between tumor classes. RESULTS: In the 21 patients, 11 bone tumors were latent or active (class 1) and 10 were aggressive (class 2). The mean age was 13.0±3.7 years, 6 (28.6%) were female, and the median and interquartile range for initial tumor size were 18.8 (5.8 to 50.6) cm 3 . Tumors that were class 2 had significantly more complications with bioactive glass use compared with class 1 tumors [0 vs. 1 (0 to 1), P =0.040]. The time of persistent fill grade 1 or 2 defects up to final follow-up was less in class 1 versus class 2 lesions ( P =0.048). CONCLUSIONS: Bioactive glass agents have utility for treating a broad variety of pediatric bone tumors after curettage. However, focusing these agents' use in treating latent or active subtypes of bone tumors may be ideal in minimizing complications and time to higher fill grade. LEVEL OF EVIDENCE: Level III - Therapeutic.

Desmoplastic Fibroma in the Distal Humerus of a 14-Year-Old Boy: A Case Report.

CASE: We present the case of a 14-year-old male who presented with a pathologic elbow fracture. Imaging demonstrated a lytic distal humerus metaphyseal lesion with a soap bubble appearance. After fracture healing, frozen sections obtained at open biopsy suggested fibrous tissue; thus, curettage and bone grafting was performed. Pathology confirmed desmoplastic fibroma. The patient experienced a recurrence 18 months later and had repeat curettage and allograft strutting. He had no evidence of re-recurrence 2 years after the second surgery. CONCLUSIONS: Desmoplastic fibroma may mimic the presentation of many bone lesions. Recurrence is common despite curettage and bone grafting. This patient performed well without wide resection.

LisFranc Fusion.

Lisfranc injuries remain a frequently missed pathology and may present as an isolated injury or as a component of a polytrauma case. Weight-bearing films or advanced imaging such as CT may be imperative in identifying or further classifying the injury. Common indications for fusion after lisfranc injury include primarily ligamentous injuries, delayed/chronic presentations, or post-traumatic arthritis, although primary fusion in the setting of acute fracture may be considered as an alternative to open reduction internal fixation techniques. The primary goals of surgery are to provide stability to the midfoot and restoration of the anatomical arch/cascade. The purpose of this video is to demonstrate a technique for tarsometatarsal joint fusion in the setting of acute lisfranc injury. This technique may be used for both ligamentous as well as bony varieties.

Posttraumatic Reconstruction of the Foot and Ankle in the Face of Active Infection.

Posttraumatic infection of the foot and ankle is a challenging issue for orthopedic surgeons. Making the diagnosis often requires combining laboratory and radiologic testing, patient examination, and history. Patient comorbidities should be identified and optimized whenever possible. Treatment must combine effective antibiotic therapy with thorough debridement of the infected zone. Reconstruction often requires a 2-staged approach using antibiotic spacers and temporary external fixation, with the goal of obtaining a functional, pain-free limb that is free of infection.