Faculty Bibliography

BACKGROUND: Infection requiring explantation remains the most devastating complication associated with implant-based breast reconstruction. There are many treatment algorithms to prevent reconstructive failure in face of infection using both oral and intravenous antibiotics. In the absence of patient-specific culture data, antibiotic selection is generally directed toward broad-spectrum coverage based on historical data. We hypothesize that reviewing our institution's microbiology data obtained from explanted implant-based breast reconstructions would provide a rational basis for antibiotic selection in the future. METHODS: A retrospective review of 902 consecutive immediate implant-based breast reconstructions at a single institution from November 2007 to May 2011 was conducted. Implant reconstructions requiring explantation or drainage by interventional radiology were identified. Patient demographics, implant characteristics, presence of skin necrosis, microbiological data, and outcomes were reviewed. RESULTS: Forty-three (4.76%) implant reconstructions requiring explantation or drainage by interventional radiology met the inclusion criteria for this study. Five patients (11.6%) had round, smooth silicone implants, and 36 (88.4%) had textured tissue expanders. Twenty-six implants were explanted because of infection; 3, because of exposure from skin necrosis; and 11, because of the combination of flap necrosis and infection; and 1, secondarily because of cancer invasion into the skin. Reconstruction was salvaged in 21 breasts (51.2%): 12 (57.1%) by implant reconstruction, 5 (23.8%) by pedicled latissimus dorsi flaps, and 4 (19.1%) with a microvascular free flap. Thirty explants had microbiology data available. The most common organism isolated was Staphylococcus epidermidis (10), followed by methicillin-sensitive Staphylococcus aureus (5), Serratia marcescens (5), Pseudomonas aeruginosa (4), enterococcus (3), Escherichia coli (2), Enterobacter (2), group B streptococcus (1), and Morganella morganii (1). Forty percent of the organisms were resistant to cefazolin; however, 86% were sensitive to gentamicin, 80% were sensitive to Levaquin, and 63% were sensitive to ciprofloxacin. CONCLUSIONS: Infection associated with implant-based breast reconstructions continues to threaten explantation and reconstructive failure. Based on our microbiological data, initial cellulitis amenable to oral antibiotics should be treated with oral fluoroquinolones as a first-line treatment. If this regimen fails, intravenous imipenem or gentamicin and vancomycin should be initiated. Obviously, clinical judgment regarding specific patient risk factors and compliance should play a role in decision making, but these data provide an evidence-based rationale for first-line oral antibiotic selection.

BACKGROUND: : Prior breast irradiation increases the rate of postoperative complications, including capsular contracture, in tissue expander/implant reconstruction. Acellular dermal matrix is heralded to decrease capsular contracture, but recent evidence suggests a possible increase in postoperative complications. The authors evaluated outcomes in patients undergoing bilateral tissue expander/implant reconstruction with acellular dermal matrix in the setting of prior unilateral irradiation. METHODS: : A case-control study was conducted on all patients undergoing bilateral, acellular dermal matrix-assisted, tissue expander/implant reconstruction with a history of previous unilateral irradiation at Memorial Sloan-Kettering Cancer Center. Complication rates were compared. RESULTS: : Twenty-three patients met inclusion criteria and had an average follow-up of 19 months (range, 4 to 60 months). The perioperative infection rate was 21.7 percent (n = 5) in irradiated breasts and 4.3 percent (n = 1) in control breasts (p = 0.079). Mastectomy skin flap necrosis, explantation, hematoma, and seroma rates were not significantly different between the groups. Sixty percent of patients had irradiated breast contracture that was one Baker grade greater than that in the nonirradiated breast. Body mass index greater than 25 and smoking history were significant independent risk factors for early postoperative complications in univariate analysis (p = 0.01). CONCLUSIONS: : Previous irradiation does not appear to increase the risk of early postoperative complications associated with acellular dermal matrix use in tissue expander/implant breast reconstruction. However, body mass index greater than 25 and smoking history are cause for caution. In addition, acellular dermal matrix does not appear to affect the degree of capsular contracture formation in the setting of prior irradiation. CLINICAL QUESTION/LEVEL OF EVIDENCE: : Therapeutic, III.

BACKGROUND: The authors have expanded upon a well-described and widely used flap in the head and neck region. The purpose of the cadaver study was to determine the feasibility, angiosome, and the potential application of this pedicled flap in bone tissue engineering of the mandible. METHODS: A total of 6 fresh human cadaver heads were dissected for a total of 12 flaps. The extended composite temporoparietal fascial flap, based on the superficial temporal artery (STA) and including cranial periosteum, was dissected and the dimensions were measured. Through a combined submandibular and preauricular incision, the mandible was exposed and the dimensions were measured from the sigmoid notch to the gonion angle and from the gonion angle to the symphysis. CT angiography and silicone injections were performed to identify the vascular anatomy of the flap. RESULTS: The combined distance from the sigmoid notch to the gonion and the gonion to the symphysis, plotted versus the cranial apex to tragus length, demonstrated adequate flap dimensions in all specimens for hemi-mandibular reconstruction. The average flap length was 16.5 +/- 1.40 cm and the average flap width was 11.4 +/- 0.98 cm, resulting in an average flap surface area of 94.5 +/- 13.08 cm. Radiographic images and silicone injections confirmed STA perfusion of the cranial periosteum. CONCLUSIONS: The extended composite temporoparietal fascial flap with periosteum can be a viable option for providing vascularized periosteum in tissue-engineered craniofacial reconstruction.

Step-stress accelerated life testing (SSALT) and fractographic analysis were performed to evaluate the reliability and failure modes of dental implant fabricated by machining (surface treated with alumina blasting/acid etching) or laser sintering for anterior single-unit replacements. Forty-two dental implants (3.75 x 10 mm) were divided in two groups (n = 21 each): laser sintered (LS) and alumina blasting/acid etching (AB/AE). The abutments were screwed to the implants and standardized maxillary central incisor metallic crowns were cemented and subjected to SSALT in water. Use-level probability Weibull curves and reliability for a mission of 50,000 cycles at 200 N were calculated. Polarized light and scanning electron microscopes were used for failure analyses. The Beta (beta) value derived from use-level probability Weibull calculation of 1.48 for group AB/AE indicated that damage accumulation likely was an accelerating factor, whereas the beta of 0.78 for group LS indicated that load alone likely dictated the failure mechanism for this group, and that fatigue damage did not appear to accumulate. The reliability was not significantly different (p > 0.9) between AB/AE (61 %) and LS (62 %). Fracture of the abutment and fixation screw was the chief failure mode. No implant fractures were observed. No differences in reliability and fracture mode were observed between LS and AB/AE implants used for anterior single-unit crowns.

BACKGROUND: : Tumors of the mandible are complex, often requiring replacement of bone, soft tissue, and teeth. The fibula flap has become a routine procedure in large tumors of the jaw, providing bone and soft tissue at the time of the resection. In current practice, dental reconstruction is delayed for 3 to 6 months, leaving the patient without teeth in the interim. This can be disfiguring and anxiety provoking for the patient. METHODS: : In this article, the authors present three patients with benign tumors of the mandible who underwent virtually guided resection, fibula reconstruction, and insertion of an implant-retained dental prosthesis in one operation. In addition, the authors report their early experience using this technique in the maxilla. RESULTS: : The authors present a case series of three patients with benign mandibular tumors and one patient with a benign maxillary tumor who underwent total reconstruction using computer-aided design and computer-aided manufacturing technology in a single stage. CONCLUSIONS: : In the right situation, total mandibular reconstruction is possible in a single stage. This is demonstrated by the successful outcomes of these patients. CLINICAL QUESTION/LEVEL OF EVIDENCE: : Therapeutic, V.

BACKGROUND: Access to the frontal sinus remains a challenging problem for the craniofacial surgeon. A wide array of techniques including minimally invasive endoscopic approaches have been described. Here we present our technique using medical modeling to gain fast and safe access for multiple indications. METHODS: Computer-aided surgery involves several distinct phases: planning, modeling, surgery, and evaluation. Computer-aided, precise cutting guides are designed preoperatively and allowed to perfectly outline and then cut the anterior table of the frontal sinus at its junction to the surrounding frontal bone. The outcomes are evaluated by postoperative three-dimensional computed tomography scan. RESULTS: Eight patients sustaining frontal sinus fractures were treated with the aid of medical modeling. Three patients (37.5%) had isolated anterior table fractures, and 4 (50%) had combined anterior and posterior table fractures, whereas 1 patient (12.5%) sustained isolated posterior table fractures. Operative times were significantly shorter using the cutting guides, and fracture reduction was more precise. There was no statistically significant difference in complication rates or overall patient satisfaction. CONCLUSIONS: The surgical approach to the frontal sinus can be made more efficient, safe, and precise when using computer-aided medical modeling to create customized cutting guides.

Although the use of zirconia abutments for implant-supported restorations has gained momentum with the increasing demand for esthetics, little informed design rationale has been developed to characterize their fatigue behavior under different clinical scenarios. However, to prevent the zirconia from fracturing, the use of a titanium connection in bi-component aesthetic abutments has been suggested. OBJECTIVE: Mechanical testing of customized thin-walled titanium-zirconia abutments at the connection with the implant was performed in order to characterize the fatigue behavior and the failure modes for straight and angled abutments. MATERIAL AND METHODS: Twenty custom-made bi-component abutments were tested according to ISO 14801:2007 either at a straight or a 25 degrees angle inclination (n=10 each group). Fatigue was conducted at 15 Hz for 5 million cycles in dry conditions at 20 degrees C+/-5 degrees C. Mean values and standard deviations were calculated for each group. All comparisons were performed by t-tests assuming unequal variances. The level of statistical significance was set at p