Neurofibroma Involving a Bifid Median Nerve in a Pediatric Patient: A Case Report.

Neurofibromas are benign peripheral nerve sheath tumors that typically develop within cutaneous nerve branches but can involve major nerves as well. They can be sporadic or associated with neurofibromatosis type 1. In this report, we describe the surgical treatment of a pediatric patient with neurofibromatosis type 1 presenting with a neurofibroma of a bifid median nerve. Involvement of the median nerve was not evident on preoperative examination or imaging, therefore altering the risk-benefit ratio of the procedure. After bifid nerve involvement was identified intraoperatively, the patient's parents were counseled on the risks and benefits of surgical excision before resuming the case. Ultimately, the neurofibroma was resected, and the patient experienced no neurological deficits after surgery.

3D printing of an interpenetrating network hydrogel material with tunable viscoelastic properties.

Interpenetrating network (IPN) hydrogel materials are recognized for their unique mechanical properties. While IPN elasticity and toughness properties have been explored in previous studies, the factors that impact the time-dependent stress relaxation behavior of IPN materials are not well understood. Time-dependent (i.e. viscoelastic) mechanical behavior is a critical design parameter in the development of materials for a variety of applications, such as medical simulation devices, flexible substrate materials, cellular mechanobiology substrates, or regenerative medicine applications. This study reports a novel technique for 3D printing alginate-polyacrylamide IPN gels with tunable elastic and viscoelastic properties. The viscoelastic stress relaxation behavior of the 3D printed alginate-polyacrylamide IPN hydrogels was influenced most strongly by varying the concentration of the acrylamide cross-linker (MBAA), while the elastic modulus was affected most by varying the concentration of total monomer material. The material properties of our 3D printed IPN constructs were consistent with those reported in the biomechanics literature for soft tissues such as skeletal muscle, cardiac muscle, skin and subcutaneous tissue.