Disruption of targeted muscle reinnervation due to heterotopic ossification in an amputated lower extremity.

A patient in his late 40s presented after 1-year following below knee amputation and targeted muscle reinnervation (TMR) with new prosthesis intolerance and pinpoint pain, suspicious for neuroma. X-ray confirmed fibular heterotopic ossification (HO). Operative revision identified HO encompassing a TMR construct with a large neuroma requiring excision and neuroplasty revision. Now approximately 1-year post procedure, the patient remains active, pain-free and ambulating with a prosthetic. Amputated extremities can be at risk for development of HO. Although described in literature, the pathophysiology and timeline for HO development is not well understood. Preventative measures for HO have been described, yet results remain variable. The gold standard for existing HO remains to be operative excision. Due to the unpredictable nature and debilitating presentation, risk of HO should be incorporated into patient-physician discussions. Additionally, new prosthetic intolerance absent of prior trauma should raise suspicion for possible HO development.

Insulin-like Growth Factor-1 Impacts p53 Target Gene Induction in UVB-irradiated Keratinocytes and Human Skin.

The tumor suppressor protein p53 limits mutagenesis in response to ultraviolet-B (UVB) light exposure by activating the transcription of genes that mitigate the damaging effects of UVB radiation on DNA. Because most nonmelanoma skin cancers (NMSCs) occur in older individuals, it is important to understand the process of mutagenesis in the geriatric skin microenvironment. Based on previous studies demonstrating that geriatric skin expresses lower levels of the growth factor insulin-like growth factor-1 (IGF-1) than young adult skin, a role for IGF-1 in the regulation of p53 target genes was investigated in both human keratinocytes in vitro and human skin explants ex vivo. The products of the p53 target genes p21 and DNA polymerase eta (pol η) were found to be increased by UVB exposure in both experimental systems, and this induction was observed to be partially abrogated by depriving keratinocytes of IGF-1 in vitro or by the treatment of keratinocytes in vitro and human skin explants with an IGF-1 receptor antagonist. Because p21 and pol η function to limit mutagenic DNA replication following UVB exposure, these results suggest that NMSC risk in geriatric populations may be due to age-dependent decreases in IGF-1 signaling that disrupt p53 function in the skin.

Reconstruction of a subtotal septorhinectomy defect with a chimeric paramedian-pericranial forehead flap.

The nose is a complex structure important for aesthetic appearance, social interaction, and respiration. Full thickness nasal defects with resection of the septum pose a significant challenge to the reconstructive surgeon due to the lack of local tissues to replace the nasal lining and significant risk of nasal collapse owing to the paucity of rigid infrastructure. The purpose of this paper is to present a unique case of nasal reconstruction utilizing a bilaminar paramedian forehead flap (combined pericranial flap and forehead flap) with embedded cantilever rib graft in a patient who underwent resection for an intranasal malignancy involving the septum and soft tissue envelope. This case serves to demonstrate the great utility in using chimeric flaps based on a single pedicle given the low patient morbidity, predictable results, and rapid recovery period.