Faculty Bibliography

PURPOSE: To compile the current evidence on biomechanical, biologic, and clinical outcomes of undersized surgical preparation protocols in dental implant surgery. MATERIALS AND METHODS: An electronic search using three different databases (PubMed, Web of Science, and Cochrane Library) and a manual hand search were performed including in vitro, animal, and clinical studies published prior to October 2015. Studies in which an undersized drilling protocol was compared with a nonundersized drilling protocol were included. RESULTS: From an initial selection of 1,655 titles, 29 studies met the inclusion criteria, including 14 biomechanical, 7 biologic, 6 biologic and biomechanical, and 2 clinical. Due to methodologic variation, meta-analysis was not performed. Several studies showed that implants inserted with an undersized drilling approach reached a significantly higher insertion torque value than conventional drilling in low-density substrates, while this effect is less evident if a thick cortical layer is present. Similar results in terms of boneto-implant contact (BIC) were achieved in the longer term between implants inserted with undersized and nonundersized protocols. Results in the short term were inconclusive. Clinical studies did not show negative outcomes for undersized drilling, although clinical evidence was sparse. No data are available on marginal bone loss. CONCLUSION: From the biomechanical standpoint, an undersized drilling protocol is effective in increasing insertion torque in low-density bone. Biologic response in long-term healing after undersized implant placement is comparable to that in the nonundersized surgical drilling protocol. Clinical studies indicate that performing an undersized drilling protocol on low-density bone is a safe procedure; however, more extensive studies are needed to confirm these data.

BACKGROUND: Venous thromboembolism encompasses a spectrum of disease, ranging from asymptomatic deep vein thrombosis to fatal pulmonary embolism. As microsurgical techniques increase in complexity, the overriding benefit from a microsurgical versus a venous thromboembolism prophylactic regimen remains unclear. This study evaluated the current recommendations and procedure-specific strategies for venous thromboembolism prophylaxis with a focus on the utility of prophylaxis in microsurgical procedures. METHODS: A review was performed to identify all articles discussing the rates of venous thromboembolism in patients undergoing microsurgical procedures. Data were summarized based on body area, including hand, breast, lower extremity, and head and neck. Guidelines for venous thromboembolism prophylaxis in microsurgical cases were established. RESULTS: The available studies demonstrate a reduction in postoperative venous thromboembolism. Unfortunately, chemoprophylaxis continues to be underused throughout plastic surgery, amid concern over the risk of bleeding complications. Based on the best available data, the use of mechanical and chemoprophylaxis should be strongly considered in all microsurgical cases. A preoperative screening algorithm based on a risk-assessment model should be used in all cases to preoperatively characterize and modify risk factors when possible, and plan for perioperative prophylaxis. CONCLUSIONS: Although not completely preventable, venous thromboembolism risks can be reduced with careful preoperative planning and medical history and the judicious use of chemoprophylaxis. Because there does not appear to be an increase in the rate of postoperative bleeding when prophylaxis is administered appropriately, the use of venous thromboembolism prophylaxis should be considered in all microsurgery patients except those at extremely high risk of bleeding.

As many as 10% of bone fractures heal poorly, and large bone defects resulting from trauma, tumor, or infection may not heal without surgical intervention. Activation of adenosine A2A receptors (A2AR) stimulates bone formation. Ticagrelor and dipyridamole inhibit platelet function by inhibiting P2Y12 receptors and platelet phosphodiesterase, respectively, but share the capacity to inhibit cellular uptake of adenosine and thereby increase extracellular adenosine levels. Because dipyridamole promotes bone regeneration by an A2AR-mediated mechanism we determined whether ticagrelor could regulate the cells involved in bone homeostasis and regeneration in a murine model and whether inhibition of P2Y12 or indirect A2AR activation via adenosine was involved. Ticagrelor, dipyridamole and the active metabolite of clopidogrel (CAM), an alternative P2Y12 antagonist, inhibited osteoclast differentiation and promoted osteoblast differentiation in vitro. A2AR blockade abrogated the effects of ticagrelor and dipyridamole on osteoclast and osteoblast differentiation whereas A2BR blockade abrogated the effects of CAM. Ticagrelor and CAM, when applied to a 3-dimentional printed resorbable calcium-triphosphate/hydroxyapatite scaffold implanted in a calvarial bone defect, promoted significantly more bone regeneration than the scaffold alone and as much bone regeneration as BMP-2, a growth factor currently used to promote bone regeneration. These results suggest novel approaches to targeting adenosine receptors in the promotion of bone regeneration.-Mediero, A., Wilder, T., Reddy, V. S. R., Cheng, Q., Tovar, N., Coelho, P. G., Witek, L., Whatling, C., Cronstein, B. N. Ticagrelor regulates osteoblast and osteoclast function and promotes bone formation in vivo via an adenosine-dependent mechanism.

An accurate and comprehensive understanding of lower extremity arterial anatomy is essential for the successful harvest and transfer of a free fibula osteoseptocutaneous flap (FFF). Minimum preoperative evaluation includes detailed history and physical including lower extremity pulse examination. Controversy exists regarding whether preoperative angiographic imaging should be performed for all patients. Elevation of an FFF necessitates division of the peroneal artery in the proximal lower leg and eradicates its downstream flow. For patients in whom the peroneal artery comprises the dominant arterial supply to the foot, FFF elevation is contraindicated. Detailed preoperative knowledge of patient-specific lower extremity arterial anatomy can help to avoid ischemia or limb loss resulting from FFF harvest. If preoperative angiographic imaging is omitted, careful attention must be paid to intraoperative anatomy. Should pedal perfusion rely on the peroneal artery, reconstructive options other than an FFF must be pursued. Given the complexity of surgical decision making, the authors propose an algorithm to guide the surgeon from the preoperative evaluation of the potential free fibula flap patient to the final execution of the surgical plan. The authors also provide 3 clinical patients in whom aberrant lower extremity anatomy was encountered and describe each patient's surgical course.

OBJECTIVE: To report the associations of oro-nasal fistulae on the patient-centered outcomes oral health-related quality of life and self-reported speech outcomes in school aged-children. DESIGN: Prospective, nonrandomized multicenter design. SETTING: Six ACPA-accredited cleft centers. PARTICIPANTS: Patients with cleft palate at the age of mixed dentition. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Prevalence of fistula and location of fistula (Pittsburgh Classification System). Patients were placed into one of three groups based on the following criteria: alveolar cleft present, no previous repair (Group 1); alveolar cleft present, previously repaired (Group 2); no congenital alveolar cleft (Group 3). Presence of fistula and subgroup classification were correlated to oral health-related quality of life (Child Oral Health Impact Profile [COHIP]) and perceived speech outcomes. RESULTS: The fistula rate was 5.52% (62 of 1198 patients). There was a significant difference in fistula rate between the three groups: Group 1 (11.15%), Group 2 (4.44%), Group 3 (1.90%). Patients with fistula had significantly lower COHIP scores (F1,1188 = 4.79; P = .03) and worse self-reported speech scores (F1,1197 = 4.27; P = .04). Group 1 patients with fistula had the lowest COHIP scores (F5,1188 = 4.78, P =.02) and the lowest speech scores (F5,1188 = 3.41, P = .003). CONCLUSIONS: Presence of palatal fistulas was associated with lower oral health-related quality of life and perceived speech among youth with cleft. The poorest outcomes were reported among those with the highest fistula rates, including an unrepaired alveolar cleft.

BACKGROUND: Reconstruction of maxillary defects following tumor extirpation is challenging because of combined aesthetic and functional roles of the maxilla. One-stage reconstruction combining osseous free flaps with immediate osseointegrated implants are becoming the standard for mandibular defects, and have similar potential for maxillary reconstruction. METHODS: A woman with maxillary Ewing sarcoma successfully treated at age 9 with neoadjuvant chemotherapy, right hemimaxillectomy, and obturator prosthetic reconstruction presented for definitive reconstruction, complaining of poor obturator fit, and hypernasality. Her reconstruction was computer-simulated by a multidisciplinary team, consisting of left hemi-Lefort I advancement and right maxillary reconstruction with a free fibula flap with immediate osseointegrated implants and dental prosthesis. RESULTS: Full dental restoration, midface projection, and oral fistula corrections were achieved in 1 operative stage using this approach. CONCLUSIONS: This patient demonstrates a successful approach for maxillary reconstruction using computer-planned orthognathic surgery with free fibula reconstruction and immediate osseointegrated implants with dental prosthesis.

BACKGROUND: The availability of acellular dermal matrix (ADM) and synthetic mesh products has prompted plastic surgeons to revisit subcutaneous implant-based breast reconstruction. The literature is limited, however, with regards to evidence on patient selection, techniques, and outcomes. METHODS: A systematic review of the Medline and Cochrane databases was performed for original studies reporting breast reconstruction with ADM or mesh, and subcutaneous implant placement. Studies were analyzed for level of evidence, inclusion/exclusion criteria for subcutaneous reconstruction, reconstruction characteristics, and outcomes. RESULTS: Six studies (186 reconstructions) were identified for review. The majority of studies (66.7%) were level IV evidence case series. Eighty percent of studies had contraindications for subcutaneous reconstruction, most commonly preoperative radiation, high body mass index, and active smoking. Forty percent of studies commenting on patient selection assessed mastectomy flap perfusion for subcutaneous reconstruction. Forty-five percent of reconstructions were direct-to-implant, 33.3% 2-stage, and 21.5% single-stage adjustable implant, with ADM utilized in 60.2% of reconstructions versus mesh. Pooled complication rates included: major infection 1.2%, seroma 2.9%, hematoma 2.3%, full nipple-areola complex necrosis 1.1%, partial nipple-areola complex necrosis 4.5%, major flap necrosis 1.8%, wound healing complication 2.3%, explantation 4.1%, and grade III/IV capsular contracture 1.2%. CONCLUSIONS: Pooled short-term complication rates in subcutaneous alloplastic breast reconstruction with ADM or mesh are low in preliminary studies with selective patient populations, though techniques and outcomes are variable across studies. Larger comparative studies and better-defined selection criteria and outcomes reporting are needed to develop appropriate indications for performing subcutaneous implant-based reconstruction.