Faculty Bibliography

Background/Purpose: b-Tricalcium phosphate (b-TCP), the most common synthetic bone replacement product, is frequently used in craniofacial reconstruction. Although solid b-TCP can be absorbed over time, the slow degradation rate (1%-3%/year) predisposes this product to exposure, infection, and fracture, limiting its use in the growing face where implants are required to grow and remodel with the patient. Our tissue engineering laboratory has successfully leveraged 3D printers to manufacture 3D-printed bioactive ceramic (3DPBC) scaffolds composed of b-TCP in an architecture which optimizes the needs of rigidity with efficient vascular ingrowth, osteogenesis, and degradation kinetics. The latter qualities are further optimized when the osteogenic agent dipyridamole (DIPY) is used. This long-term animal study reports on the new degradation kinetics profile achievable through this novel manufacturing and tissue engineering protocol. Methods/Description: Twenty-two 1-month-old (immature) New Zealand white rabbits underwent creation of unilateral 10 mm calvarial defects with ipsilateral 3.5 +/- 3.5 mm alveolar defects. Each defect was repaired with b-TCP 3DPBC scaffolds coated with 1000 mM DIPY. Rabbits were killed at 8 weeks (n = 6), 6 months (n = 8), and 18 months (n = 8). Bone regeneration and scaffold degradation were calculated using micro-CT images and analyzed in Amira software. Cranial and maxillary suture patency and bone growth were qualitatively analyzed using histologic analysis.
Result(s): Results are reported as a percentage of volumetric space occupied by either scaffold or bone. When comparing time points 8 weeks, 6 months, and 18 months, scaffolds showed significant decreased defect occupancy in calvaria (23.6% +/- 3.6%, 15.2% +/- 1.7%, 5.1% +/- 3.4%; P < .001) and in alveoli (21.5% +/- 3.9%, 6.7% +/- 2.7%, 0.1% +/- 0.2%; P < .001), with annual degradation rates 55.9% and 94.2%, respectively. Between 8 weeks and 18 months, significantly more bone regenerated in calvarial defects (25.8% +/- 6.3% vs 55.7% +/- 10.3%, P < .001) and no difference was found in alveolar defects (28.4% +/- 6.8% vs 32.4% +/- 8.0%, P = .33). Histology showed vascularized, organized bone without suture fusion.
Conclusion(s): The degradation kinetics of b-TCP can be altered through 3D printing and addition of an osteogenic agent. Our study demonstrates an acceleration of b-TCP degradation from 1% to 3% a year to 55% to 95% a year. Absorbed b-TCP is replaced by vascularized bone and there is no damage noted to the growing suture. This additive manufacturing and tissue engineering protocol has implication to future reconstruction of the craniofacial skeleton

BACKGROUND:Three-dimensionally-printed bioceramic scaffolds composed of β-tricalcium phosphate delivering the osteogenic agent dipyridamole can heal critically sized calvarial defects in skeletally mature translational models. However, this construct has yet to be applied to growing craniofacial models. In this study, the authors implanted three-dimensionally-printed bioceramic/dipyridamole scaffolds in a growing calvaria animal model and evaluated bone growth as a function of geometric scaffold design and dipyridamole concentration. Potential adverse effects on the growing suture were also evaluated. METHODS:Bilateral calvarial defects (10 mm) were created in 5-week-old (approximately 1.1 kg) New Zealand White rabbits (n = 16 analyzed). Three-dimensionally-printed bioceramic scaffolds were constructed in quadrant form composed of varying pore dimensions (220, 330, and 500 μm). Each scaffold was coated with collagen and soaked in varying concentrations of dipyridamole (100, 1000, and 10,000 μM). Controls consisted of empty defects. Animals were killed 8 weeks postoperatively. Calvariae were analyzed using micro-computed tomography, three-dimensional reconstruction, and nondecalcified histologic sectioning. RESULTS:Scaffold-induced bone growth was statistically greater than bone growth in empty defects (p = 0.02). Large scaffold pores, 500 μm, coated in 1000 μM dipyridamole yielded the most bone growth and lowest degree of scaffold presence within the defect. Histology showed vascularized woven and lamellar bone along with initial formation of vascular canals within the scaffold lattice. Micro-computed tomographic and histologic analysis revealed patent calvarial sutures without evidence of ectopic bone formation across all dipyridamole concentrations. CONCLUSION/CONCLUSIONS:The authors present an effective pediatric bone tissue-engineering scaffold design and dipyridamole concentration that is effective in augmentation of calvarial bone generation while preserving cranial suture patency.

BACKGROUND:The exophthalmos and class III malocclusion seen in Crouzon syndrome can be treated by Le Fort III advancement/distraction. However, reconstructive options for zygomatic retrusion are limited. The authors describe the repair of isolated exorbitism in a patient with Crouzon syndrome, via bilateral zygomatic rotation-advancement. METHODS:A 34-year-old woman with Crouzon syndrome complained of exorbitism and malar hypoplasia. Four years prior, she declined Le Fort III advancement and underwent orthodontic/orthognathic correction of malocclusion. Radiographs were used to develop a computerized surgical plan. Bilateral periorbital osteotomy with advancement/rotation of the zygomatic process was performed using custom osteotomy guides and plates. Images obtained immediately postoperative and 3- and 19-month postoperative were compared to assess surgical stability, accuracy, and soft tissue changes. RESULTS:Decreased globe exposure and increased malar prominence have improved facial balance. Superimposed pre- and postoperative radiographs demonstrate bilateral advancement of the zygomatic body and inferior orbital rim. Superimposition of immediate postoperative and 19-month radiographs showed no relapse. Soft tissue histogram showed increased prominence of the malar eminence, lateral orbital rim, and cheek. CONCLUSIONS:Zygomatic rotation-advancement proved a safe, effective, stable, and predictable treatment for isolated malar hypoplasia in a patient with Crouzon syndrome. Virtual planning can enhance novel complex craniofacial procedures.

INTRODUCTION/BACKGROUND:Simulation is a standard component of residency training in many surgical subspecialties, yet its impact on knowledge and skills acquisition in plastic surgery training remains poorly defined. We evaluated the potential benefits of simulation-based cleft surgery learning in plastic surgery resident education through a prospective, randomized, blinded trial. METHODS:Thirteen plastic surgery residents were randomized to a digital simulator or textbook demonstrating unilateral cleft lip (UCL) repair. The following parameters were evaluated before (pre-intervention) and after (post-intervention) randomization: knowledge of surgical steps, procedural confidence, markings performance on a three-dimensional (3D) stone model, and surgical performance using a hands-on/high-fidelity 3D haptic model. Participant satisfaction with either educational tool was also assessed. Two expert reviewers blindly graded markings and surgical performance. Intra-class correlation coefficients (ICC) were calculated. Wilcoxon signed-rank and Mann-Whitney U tests were used. RESULTS:Interrater reliability was strong for pre-intervention and post-intervention grading of markings (ICC=0.97; p<0.001 and ICC=0.96; p<0.001) and surgical (ICC=0.83; p=0.002 and ICC=0.81; p=0.004) performance. Post-intervention surgical knowledge (40.3±4.4 vs. 33.5±3.7; p=0.03), procedural confidence (24.0±7.0 vs. 14.7±2.3; p=0.03), markings performance (8.0±2.5 vs. 2.9±3.1; p=0.03), and surgical performance (12.3±2.5 vs. 8.2±2.3; p=0.04) significantly improved in the digital simulation group compared to pre-intervention, but not in the textbook group. All participants were more satisfied with the digital simulator as an educational tool (27.7±2.5 vs. 14.4±4.4; p<0.001). CONCLUSIONS:We present evidence suggesting that digital cognitive simulators lead to significant improvement in surgical knowledge, procedural confidence, markings performance, as well as surgical performance.

This study investigates a comprehensive model of bone regeneration capacity of dypiridamole-loaded 3D-printed bioceramic (DIPY-3DPBC) scaffolds composed of 100% beta-tricalcium phosphate (β -TCP) in an immature rabbit model through the time of facial maturity. The efficacy of this construct was compared to autologous bone graft, the clinical standard of care in pediatric craniofacial reconstruction, with attention paid to volume of regenerated bone by 3D reconstruction, histologic and mechanical properties of regenerated bone, and long-term safety regarding potential craniofacial growth restriction. Additionally, long-term degradation of scaffold constructs was evaluated. At 24 weeks in vivo, DIPY-3DPBC scaffolds demonstrated volumetrically significant osteogenic regeneration of calvarial and alveolar defects comparable to autogenous bone graft with favorable biodegradation of the bioactive ceramic component in vivo. Characterization of regenerated bone reveals osteogenesis of organized, vascularized bone with histologic and mechanical characteristics comparable to native bone. Radiographic and histologic analyses were consistent with patent craniofacial sutures. Lastly, through application of 3D morphometric facial surface analysis, our results support that DIPY-3DPBC scaffolds do not cause premature closure of sutures and preserve normal craniofacial growth. Based on this novel evaluation model, this DIPY-3DPBC scaffold strategy is a promising candidate as a safe, efficacious pediatric bone tissue engineering strategy.

Treatment of cleft lip and palate ordinarily requires multiple interventions spanning the time of birth to adulthood. Restriction of facial growth, a common occurrence in affected children, is due to multiple factors. There are multiple surgical and therapeutic options, which may have influence on facial growth in these patients. As restriction to facial development can have significant implications to form, function, and psychological well-being, practitioners should have an appreciation for the effects of the different cleft therapies to facial growth. We have outlined and thoroughly reviewed in chronological order all of the interventions from birth to adulthood necessary in the comprehensive care of the patient with cleft lip and palate, along with the effects they may or may not have on facial growth.

BACKGROUND:There is no quantitative evidence supporting one unilateral cleft lip (UCL) repair technique over the other with regard to scarring. We sought to evaluate the difference between the extended Mohler and Millard techniques, using 3 scar assessment scales. METHODS:Postoperative frontal and basal photographs of patients undergoing UCL repair were reviewed. Three validated scar assessment scales were used: the Manchester Scar Scale (MSS), modified scar-rating scale (MSRS), and Stony Brook Scar Evaluation Scale. Lip and nose scars were rated by 5 independent raters using each of the scales. Interrater reliability was assessed using the intraclass correlation coefficient (ICC). RESULTS:Assessment of 116 images for 58 consecutive patients undergoing UCL repair (36 extended Mohler, 22 Millard) was performed. Interrater reliability was excellent for lip scars (ICCs, 0.903 [0.857-0.938] for MSS, 0.913 [0.872-0.944] for MSRS, and 0.850 [0.775-0.902] for SBES) and moderate for nose scar assessment (ICCs, 0.714 [0.579-0.816] for MSS, 0.693 [0.548-0.802] for MSRS, and 0.565 [0.359-0.720] for SBES). No statistically significant difference was found between the extended Mohler and Millard repairs in mean lip scar scores (MSS, 6.983 ± 1.469 vs 6.772 ± 1.175, P = 0.571; MSRS, 5.433 ± 1.530 vs 5.481 ± 1.290, P = 0.902; SBES, 3.633 ± 0.977 vs 3.446 ± 0.995, P = 0.483) or nose scar scores (MSS, 5.644 ± 1.131 vs 5.491 ± 0.689, P = 0.523; MSRS, 4.233 ± 0.987 vs 3.991 ± 0.705, P = 0.320; SBES, 3.933 ± 0.750 vs 4.018 ± 0.486, P = 0.603). CONCLUSIONS:Using 3 validated scar assessment scales, no significant difference was found between the extended Mohler and Millard techniques in terms of lip or nose scars.

Operative experience for the contemporary trainee has become exceedingly more challenging in the setting of more stringent hospital regulations. Surgical training is thus shifting toward more self-directed, independent learning to maximize operative opportunities as they become available; yet, this can prove difficult for complex surgeries like craniofacial procedures. The intricate anatomy and fine reconstructive techniques employed cannot be readily depicted onto a two-dimensional page. To address this educational gap, the Craniofacial Interactive Virtual Assistant-Pro Edition (CIVA-Pro) was developed as a web-based surgical simulator to aid learners with conceptualizing the surgical principles utilized in these cases. The current work reviews the Bilateral Sagittal Split Osteotomy module of CIVA-Pro, providing detailed narratives for each chapter with expert commentary on broadened indications and future directions.

BACKGROUND:The Extended Mohler cleft lip repair restores upper lip form using a columellar flap to fill the defect created by the downward rotation of Cupid's bow. The resulting columella incision is mentioned as a potential drawback. This study seeks to evaluate the morbidity of the resulting scar. MATERIALS AND METHODS/METHODS:This retrospective study enrolled 50 unilateral cleft lip patients treated using the Extended Mohler repair. 5 reviewers examined post-operative images. Three validated scar assessment scales were utilized: Manchester Scar Scale (MSS), Modified Scar-Rating Scale (MSRS), and Stony Brook Scar Evaluation Scale (SBSES). A scar score for the lip and columellar portion of each patient was determined. RESULTS:Three different scar scales demonstrated significantly better scar quality for the columellar portion of the scar compared to the lip portion. The average score for the lip and columella using the MSS was 7.0 ± 1.4 and 5.7 ± 1.1 (P <0.001). The average score for the lip and columella using the MSRS was 5.5 ± 1.4 and 4.3 ± 0.9 (P <0.001). The average score for the lip and columella using the SBSES was 3.5 ± 1.1 and 3.9 ± 0.7 (P = 0.014). The intraclass correlation coefficient for lip scar assessments was 0.901 (MSS), 0.91 (MSRS), and 0.873 (Stony Brook Evaluation Scale [SBES]). The intraclass correlation coefficient for columellar scar assessment was 0.786 (MSS), 0.761 (MSRS), and 0.726 (SBES). CONCLUSION/CONCLUSIONS:The Extended Mohler unilateral cleft lip columellar scar is of superior quality compared to the lip portion. This analysis ameliorates one of the major concerns regarding the Extended Mohler cleft lip repair.