Debilitating hearing and balance deficits often arise through damage to the inner ear's hair cells. For humans and other mammals, such deficits are permanent, but non-mammalian vertebrates can quickly recover hearing and balance through their innate capacity to regenerate hair cells. The biological basis for this difference has remained unknown, but recent investigations in wounded balance epithelia have shown that proliferation follows cellular spreading at sites of injury. As mammalian ears mature during the first weeks after birth, the capacity for spreading and proliferation declines sharply. In seeking the basis for those declines, we investigated the circumferential bands of F-actin that bracket the apical junctions between supporting cells in the gravity-sensitive utricle. We found that those bands grow much thicker as mice and humans mature postnatally, while their counterparts in chickens remain thin from hatching through adulthood. When we cultured utricular epithelia from chickens, we found that cellular spreading and proliferation both continued at high levels, even in the epithelia from adults. In contrast, the substantial reinforcement of the circumferential F-actin bands in mammals coincides with the steep declines in cell spreading and production established in earlier experiments. We propose that the presence of thin F-actin bands at the junctions between avian supporting cells may contribute to the lifelong persistence of their capacity for shape change, cell proliferation, and hair cell replacement, while the postnatal reinforcement of the F-actin bands in maturing humans and other mammals may have an important role in limiting hair cell regeneration.
Craniofacial fractures and bony defects are common causes of morbidity and contribute to increasing health care costs. Successful regeneration of bone requires the concomitant processes of osteogenesis and neovascularization. Current methods of repair and reconstruction include rigid fixation, grafting, and free tissue transfer. However, these methods carry innate complications, including plate extrusion, nonunion, graft/flap failure, and donor site morbidity. Recent research efforts have focused on using stem cells and synthetic scaffolds to heal critical-sized bone defects similar to those sustained from traumatic injury or ablative oncologic surgery. Growth factors can be used to augment both osteogenesis and neovascularization across these defects. Many different growth factor delivery techniques and scaffold compositions have been explored yet none have emerged as the universally accepted standard. In this review, we will discuss the recent literature regarding the use of stem cells, growth factors, and synthetic scaffolds as alternative methods of craniofacial fracture repair.
IMPORTANCE Same-day Mohs reconstructive surgery is not always possible; moreover, a delay can offer benefits such as improved surgical planning and increased blood supply to the cauterized wound bed. However, recent work found that delaying reconstruction by more than 2 days increases the postoperative complication rate. OBJECTIVE To review the outcomes of Mohs micrographic surgery (MMS) reconstruction with respect to patient-and surgery-specific variables, especially timing of repair. DESIGN, SETTING, AND PARTICIPANTS Retrospective, single-institution cohort study of patients who underwent Mohs reconstructive surgery by 1 of the 2 senior authors from January 2012 to March 2017 for cutaneous squamous cell carcinoma or basal cell carcinoma. No patients had to be excluded for inadequate follow-up or incomplete medical records. MAIN OUTCOMES AND MEASURES Postoperative complications including hematoma, infection, dehiscence, and partial or full graft or flap loss. RESULTS A total of 633 defects in 591 patients (median [range] age, 65 [21-96] years; 333 [56.3%] female) were identified over the 5-year period. Reconstructions occurred from less than 24 hours to 32 days after MMS, with 229 (36.2%) delayed longer than 48 hours. Patient-specific variables reviewed included comorbidities, age, smoking status, and use of anticoagulant or antiplatelet medications. Surgery-specific variables analyzed included location and size of defect, time interval between MMS and reconstruction, and reconstructive modalities. Single-variable analysis was performed to determine whether each variable was associated with postoperative complications. On multivariable binary logistic regression, smoking status (odds ratio [OR], 2.46; 95% CI, 1.29-4.71; P = .007), defect size (OR exp(B), 1.04; 95% CI, 1.01-1.06; P = .006), full-thickness defects (OR, 1.56; 95% CI, 1.08-2.25; P = .02), interpolated flaps with cartilage grafting (OR, 8.09; 95% CI, 2.65-24.73; P < .001), and composite grafts (OR, 6.35; 95% CI, 2.25-17.92; P < .001) were associated with an increased risk of postoperative complications. CONCLUSIONS AND RELEVANCE We found no association between timing of Mohs reconstructive surgery and complications, indicating that a delayed repair did not increase the risk of infection or flap failure. Variables associated with an increased risk of postoperative complications include smoking status, size of the defect, full-thickness defects, interpolated flaps with cartilage grafting, and the use of composite grafts. LEVEL OF EVIDENCE 3.
This article discusses the importance of obtaining the correct anatomic location of a nasal obstruction in the pediatric patient, the relative and absolute indications for septoplasty, and surgical techniques. Because disruption of the developing nasal septum can alter craniofacial growth patterns, the current understanding of the effect of septoplasty on craniofacial growth is also discussed.
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