David A. Zopf

Bioresorbable Airway Splint Created with a Three-Dimensional Printer

An infant with localized bronchial malacia was treated with a computer-printed bioresorbable three-dimensional splint. Placement of the splint resulted in improved ventilation.

The versatility of the temporoparietal fascia flap in head and neck reconstruction

OBJECTIVES The temporoparietal fascia flap (TPFF) is a versatile tool in head and neck reconstruction. This article aims to describe the spectrum of TPFF applications through a series of case studies and related review of the literature. METHODS Medical records were reviewed to identify cases that represent major TPFF application categories. A literature review was performed to support the presentation and discussion of each case category. RESULTS Seven cases were identified each representing a distinct application category. These included auricular reconstruction, hair-bearing tissue transfer, facial soft tissue augmentation, cutaneous and mucosal oncologic defect repair, reconstruction after salvage laryngectomy, skull base reconstruction, and orbital reconstruction. CONCLUSION The TPFF is a uniquely versatile tool in head and neck reconstructive surgery. Outstanding in its pliable, ultra-thin yet hardy and highly vascular form, the temporoparietal fascia flap is a workhorse for the creative head and neck reconstructive surgeon.

Treatment of severe porcine tracheomalacia with a 3-dimensionally printed, bioresorbable, external airway splint.

IMPORTANCE The study demonstrates use of a novel intervention for severe tracheobronchomalacia (TBM). OBJECTIVE To test a novel, 3-dimensionally (3D) printed, bioresorbable airway splint for efficacy in extending survival in a porcine model of severe, life-threatening TBM. DESIGN AND PARTICIPANTS A randomized, prospective animal trial was used to evaluate an external airway splint as treatment of severe, life-threatening TBM in a multi-institutional, multidisciplinary collaboration between a biomedical engineering department and an academic animal surgery center. Six 2-month-old Yorkshire pigs underwent tracheal cartilage division and inner tracheal lumen dissociation and were randomly assigned to splint treatment (n = 3) or control groups (n = 3). Two additional pigs had the splint placed over their normal trachea. INTERVENTIONS A 3D-printed, bioresorbable airway splint was assessed in a porcine animal model of life-threatening TBM. The open-cylindrical, bellow-shaped, porous polycaprolactone splint was placed externally and designed to suspend the underlying collapsed airway. Two additional animals were splinted without model creation. MAIN OUTCOMES AND MEASURES The observer-based Westley Clinical Croup Scale was used to assess the clinical condition of animals postoperatively. Animal survival time was noted. RESULTS Complete or nearly complete tracheal lumen collapse was observed in each animal, with resolution of symptoms in all of the experimental animals after splint placement. Using our severe TBM animal model, survival was significantly longer in the experimental group receiving the airway splint after model creation than in the control group (P = .0495). CONCLUSIONS AND RELEVANCE A multidisciplinary effort producing a computer-aided designed, computer-aided manufactured bioresorbable tracheobronchial splint was tested in a porcine model of severe TBM and was found to extend survival time. Mortality in the splinted group was ascribed to the TBM model based on the lack of respiratory distress in splinted pigs, long-term survival in animals implanted with the splint without TBM, and necropsy findings.

Computer Aided–Designed, 3-Dimensionally Printed Porous Tissue Bioscaffolds for Craniofacial Soft Tissue Reconstruction

Objective To determine the potential of an integrated, image-based computer-aided design (CAD) and 3-dimensional (3D) printing approach to engineer scaffolds for head and neck cartilaginous reconstruction for auricular and nasal reconstruction. Study Design Proof of concept revealing novel methods for bioscaffold production with in vitro and in vivo animal data. Setting Multidisciplinary effort encompassing 2 academic institutions. Subjects and Methods Digital Imaging and Communications in Medicine (DICOM) computed tomography scans were segmented and utilized in image-based CAD to create porous, anatomic structures. Bioresorbable polycaprolactone scaffolds with spherical and random porous architecture were produced using a laser-based 3D printing process. Subcutaneous in vivo implantation of auricular and nasal scaffolds was performed in a porcine model. Auricular scaffolds were seeded with chondrogenic growth factors in a hyaluronic acid/collagen hydrogel and cultured in vitro over 2 months’ duration. Results Auricular and nasal constructs with several types of microporous architecture were rapidly manufactured with high fidelity to human patient anatomy. Subcutaneous in vivo implantation of auricular and nasal scaffolds resulted in an excellent appearance and complete soft tissue ingrowth. Histological analysis of in vitro scaffolds demonstrated native-appearing cartilaginous growth that respected the boundaries of the scaffold. Conclusion Integrated, image-based CAD and 3D printing processes generated patient-specific nasal and auricular scaffolds that supported cartilage regeneration.

Biomechanical evaluation of human and porcine Auricular cartilage

The mechanical properties of normal auricular cartilage provide a benchmark against which to characterize changes in auricular structure/function due to genetic defects creating phenotypic abnormalities in collagen subtypes. Such properties also provide inputs/targets for auricular reconstruction scaffold design. Several studies report the biomechanical properties for septal, costal, and articular cartilage. However, analogous data for auricular cartilage are lacking. Therefore, our aim in this study was to characterize both whole‐ear and auricular cartilage mechanics by mechanically testing specimens and fitting the results to nonlinear constitutive models.

CT scans in childhood and risk of leukaemia and brain tumours

1that excess risk of leukaemia is associated with the doses of ionisation radiation to red bone marrow from CT scans, which provides solid justifi cation for the “image gently” campaign. However, we disagree with their statement that the dose response of leukaemia does not vary with the age at exposure. According to Cristy, 2 the amount and distribution of red bone marrow changes dramatically with age in childhood, and gradually concentrates in some body parts at adulthood. We have shown 3 that variation in physical bone density in people of the same age, and uneven body development with age, can greatly aff ect the accuracy of the age-dependent estimation of radiation doses to red bone marrow. Therefore, one should be careful in applying the reported excess relative risk per unit dose to estimate the leukaemia risk in a large population. In Pearce and colleagues’ study, the red-bone-marrow dose from a CT scan is a single number for a specifi c age and sex. This is clearly an oversimplifi cation which could have caused the reported irrelevance of the dose response of leukaemia to such personal characteristics as age at exposure or time since exposure. The lack of association is in stark contrast to many previous studies that have reported a sharp decrease in risk with age at exposure. 4

Computer-Aided Design and 3D Printing to Produce a Costal Cartilage Model for Simulation of Auricular Reconstruction.

M icrotia, or underdevelopment of the auricle, affects approximately 0.03% of live births. Carving an auricular cartilage framework from autogenous cartilage—the most common technique for auricular reconstruction—is one of the most challenging skills for the reconstructive surgeon to learn. Given the potential morbidity associated with technical errors in framework carving, opportunities for acquisition of this skill are limited. It is critical for surgeons to be able to practice their carving skills. This presents an opportunity for surgical simulation. Materials previously used for simulation of auricular framework carving include carrots, potatoes, porcine/bovine/human cadaveric costal cartilage, and dental impression material. These materials poorly represent the geometry, texture, and size of the harvested costal cartilage presented to the reconstructive surgeon. There is a commercially available model (Medicon, Tuttlingen, Germany) that is based on adult rib and is costly. To better represent pediatric rib geometry and texture, techniques were developed to produce negative molds from harvested pediatric rib cartilage. While these methods are an improvement on the simulation of shape and size, questions remained on the similarity of the material to costal cartilage. In this report, we aim to use computer-aided design and 3dimensional (3D) printing to create a representative pediatric costal cartilage model for simulation of auricular framework reconstruction. Furthermore, with computed tomography scan data, the potential for patient-specific simulation is introduced, allowing for surgical planning.

Full-Thickness Skin Graft Overlying a Separately Harvested Auricular Cartilage Graft for Nasal Alar Reconstruction

OBJECTIVE To evaluate the aesthetic and functional outcomes of a full-thickness skin graft and a separately harvested auricular cartilage graft for nasal alar defects created by Mohs micrographic surgery. DESIGN Twenty patients with deep Mohs micrographic surgery defects of the nasal ala who underwent reconstruction with a full-thickness skin graft and an auricular cartilage graft were prospectively studied at a single tertiary care institution between 2010 and 2011 in a nonrandomized, nonblinded study. An ordinal 5-point Likert scale evaluation of overall outcomes was performed by 4 independent surgeon raters. RESULTS The mean outcome for use of the full-thickness skin and auricular cartilage graft construct was a score of 2.3 on a scale of 1 through 5, with 1 being excellent and 5 being poor. The mean duration of follow-up was 6 months, with a range of 5 weeks to 23 months. There were no clinically meaningful losses of constructs in the patients studied. CONCLUSION A full-thickness skin graft and a separately harvested auricular cartilage graft are valuable and reliable tools for reconstructing deep nasal alar defects that require support to prevent alar retraction or collapse, particularly when a single-stage procedure is preferred or necessary because of medical comorbidities.

Patient and family satisfaction in a pediatric otolaryngology clinic.

OBJECTIVES Identify factors related to patient/family satisfaction in an academic pediatric otolaryngology clinic and suggest strategies to improve patient and family satisfaction. METHODS Patients and families were surveyed following clinic encounters between May, 2010 and April, 2011. Review of an ongoing continuous quality improvement (CQI) effort. Univariable and multivariable ordinal logistic regression analyses were used to evaluate the relationship between reception area and examination room wait times, assessment of the provider, and clinic volume with overall satisfaction. RESULTS 1415 clinical encounters in the pediatric otolaryngology clinic resulted in 962 responses for a response rate of 68%. Ordinal logistic regression showed a significant relationship between overall satisfaction and satisfaction with the provider (cumulative odds ratio [COR]=51.0; 95% CI: 29.5, 88.2; P<0.001), examination room wait time (COR=23.0; 95% CI: 15.0, 35.1; P<0.001), reception area wait time (COR=13.6; 95% CI: 9.41, 19.8; P<0.001), and increases in clinic volume below 22 patients per day (COR=0.86; 95% CI: 0.75, 0.99; P=0.033). Multivariable analysis showed that satisfaction with provider (COR=32.2; 95% CI: 14.5, 71.8; P<0.001), reception area wait time (COR=3.8; 95% CI: 1.8, 7.6; P<0.001), and examination room wait time (COR=2.8; 95% CI: 1.3, 6.1; P=0.005) were independently associated with overall satisfaction. CONCLUSIONS Examination room wait times and reception area wait times are associated with overall satisfaction and should be minimized.

Do open and endoscopic resection approaches to juvenile nasopharyngeal angiofibroma result in similar blood loss and recurrence rates

BACKGROUND Juvenile nasopharyngeal angiofibromas (JNAs) are rare, slow-growing tumors of the nasal cavity and skull base that account for approximately 0.5% of all head and neck tumors. This benign, highly vascular tumor is almost exclusively found in adolescent males. JNAs classically present with nasal obstruction and/or recurrent epistaxis. More advanced tumors can present with facial asymmetry, facial swelling, and visual disturbances. Histologically, JNAs are nonencapsulated tumors comprised of an irregular network of blood vessels set in fibroblastic stroma. They are thought to originate from the sphenopalatine foramen and initially grow into the nasal cavity and pterygopalatine fossa. More advanced lesions are locally destructive and can extend into the infratemporal fossa, orbit, and middle cranial fossa. There are a number of staging systems for JNAs based on the size and extent of the tumor; however, there is no current consensus regarding the optimal classification. The treatment of JNAs is surgical excision, often in combination with preoperative angiography and embolization of the vessels supplying the tumor. JNAs were traditionally resected via open surgical approaches; however, with the advancement of endoscopic skull base techniques, an increasing number of these tumors are being removed endoscopically.