An investigation of environmental factors influencing quantitative accuracy and recognition rate of craniofacial reconstructions

Aim: The accuracy of forensic craniofacial reconstruction/approximation can be influenced by a number of environmental factors. The aim of this study was to investigate how different average facial soft tissue depth datasets might influence the accuracy of craniofacial reconstruction employing two accuracy assessment methods;face-pool comparison and geometric surface comparison.Methodology: Six craniofacial reconstructions were produced using three-dimensional modeling software from 3D skull images of live Korean adult subjects generated by cone-beam computerized tomography. The six craniofacial reconstructions were divided into two groups: three created using an outdated Korean averaged facial soft tissue thickness dataset, and three created using a recent one. The accuracies for six craniofacial reconstructions were measured using face-pool comparison and geometric surface comparison methods to estimate the influential level of average facial soft tissue depth datasets to craniofacial reconstructions. Results: In face-pool comparisons, the recent dataset demonstrated a higher recognition rate than the outdated one. The results were compared to those of geometric surface comparisons using the same six craniofacial reconstructions; a positive correlation was detected. Interpretation: The results suggest that appropriate averaged facial soft tissue depth datasets influence the accuracy of craniofacial reconstructions, and that the geometric surface comparison method might be interchangeable with face-pool comparison method to evaluate the accuracy of craniofacial reconstructions

Characterization of bone substitute beta946; -TCP block for maxillofacial reconstruction / Caracterización del bloque beta946; -TCP de sustitución ósea para la reconstrucción maxilofacial

SUMMARY: The aim of this study was to characterize a commercial beta tricalcium phosphate (β-TCP) block allograft for use in maxillofacial reconstruction, evaluating its homogeneity, porosity and mineralization. Two commercial 5 x 5 x10 mm chronOS Vivify β-TCP blocks were used, which were evaluated by a STEM SU-3500 variable pressure scanning electron microscope (SEM-STEM) (Hitachi, Japan). For the semi-quantitative microanalysis of elements, the QUANTAX 100 energy dispersive x-ray spectrometer detector (EDX) (Bruker, Germany) was used. The homogeneity of the structural morphology, macropore and micropore size and component homogeneity were evaluated. The microscopic analysis showed micropores of 164.92 mm (± 35.032 mm) in diameter in the outer area and micropores in the inner area of 54.44 mm (± 17.676 mm). The formation of porosities and irregularities present in the block was heterogeneous between the outer and inner surfaces. The mineral content of the blocks presented homogeneity with the presence of carbon (2.02 %), oxygen (44.33 %), phosphate (16.62 %) and calcium (37.87 %). The β-TCP block can be used in bone reconstruction but the presence of reduced macropore and micropore sizes could limit efficiency in the substitution and bone regeneration phase.

RESUMEN: El objetivo de este estudio fue caracterizar un aloinjerto de bloqueo de fosfato tricálcico (β-TCP) comercial para su uso en la reconstrucción maxilofacial, evaluando su homogeneidad, porosidad y mineralización. Se utilizaron dos bloques comerciales de 5 x 5 x 10 mm de vivify β-TCP de chronOS, que se evaluaron mediante un microscopio electrónico de barrido de presión variable STEM SU-3500 (SEM-STEM) (Hitachi, Japón). Para el microanálisis de elementos semicuantitativo, se utilizó el detector de espectrómetro de rayos X de dispersión de energía QUANTAX 100 (EDX) (Bruker, Alemania). Se evaluó la homogeneidad de la morfología estructural, el tamaño del macroporo y microporo y la homogeneidad de los componentes. El análisis microscópico mostró microporos de 164,92 mm (± 35,032 mm) de diámetro en el área externa y microporos en el área interna de 54,44 mm (± 17,676 mm). La formación de porosidades e irregularidades presentes en el bloque fue heterogénea entre las superficies externas e internas. El contenido mineral de los bloques presentó homogeneidad con la presencia de carbono (2,02 %), oxígeno (44,33 %), fosfato (16,62 %) y calcio (37,87 %). El bloque β-TCP se puede utilizar en la reconstrucción ósea, pero la presencia de macroporos y tamaños de microporos reducidos podría limitar la eficacia en la fase de sustitución y regeneración ósea.

Complications after craniofacial reconstruction with calcium phosphate cements: a case report and review of the literature

Among different graft materials for craniofacial reconstruction, calcium phosphate cements have the advantages of alloplastic grafts and wide use. The authors report a case of foreign body reaction following frontal reconstruction with JectOS (an injectable calcium orthophosphate cement; Kasios) and reviewed the literature on complications of this material after craniofacial reconstruction from 2002 to 2017. Complications were categorized into two groups: immunologic reactions (consisting of seroma collection, chronic sinus mucosa swelling, and foreign body reaction) and non-immune events (infection, fragmentation, and ejection). It is wise to use calcium phosphate-based material only in selected cases with small defects, and long-term follow-up is needed to observe their consequences.

3D skull registration method based on contour curve feature / 中国法医学杂志

Objective Aiming at the 3D skull model with great difference in initial posture and resolution, a skull registration method based on feature contour line is proposed in the paper. Methods Firstly, contour lines which include eye, nose, temporal bone, maxilla and jawbone are extracted; Secondly, the types of contour are distinguished according to their length and shortest distance between them, and the corresponding relationship is established between the two skulls needed to register, thus the coarse registration of skulls is completed; Finally, an improved iterative closest point (ICP) algorithm is proposed by integrating weight into ICP, which is used to complete fine registration of skulls, thus the accurate registration of skulls is achieved at last. Results Registration between a unknown skull and 300 reference skulls is done, and the experimental results show that the proposed registration method could complete 3D skull registration, which could get high accuracy and speed in fine registration. Conclusion So the skull registration method based on local contour line is an accurate and fast 3D skull registration method.

Structural and mechanical characterization of custom design cranial implant created using additive manufacturing

Background: Reconstruction of customized cranial implants with a mesh structure using computer-assisted design and additive manufacturing improves the implant design, surgical planning, defect evaluation, implant-tissue interaction and surgeon's accuracy. The objective of this study is to design, develop and fabricate cranial implant with mechanical properties closer to that of bone and drastically decreases the implant failure and to improve the esthetic outcome in cranial surgery with precision fitting for a better quality of life. A customized cranial mesh implant is designed digitally, based on the Digital Imaging and Communication in Medicine files and fabricated using state of the Art-Electron Beam Melting an Additive Manufacturing technology. The EBM produced titanium implant was evaluated based on their mechanical strength and structural characterization. Results: The result shows, the produced mesh implants have a high permeability of bone ingrowth with its reduced weight and modulus of elasticity closer to that the natural bone thus reducing the stress shielding effect. Scanning electron microscope and micro-computed tomography (CT) scanning confirms, that the produced cranial implant has a highly regular pattern of the porous structure with interconnected channels without any internal defect and voids. Conclusions: The study reveals that the use of mesh implants in cranial reconstruction satisfies the need of lighter implants with an adequate mechanical strength, thus restoring better functionality and esthetic outcomes for the patients.

Effects of Different Doses of Sufentanil Citrate on Analgesic Effects of Crouzon Syndrome Children with Cra-niofacial Reconstruction / 中国药房

OBJECTIVE:To investigate the effects of different doses of sufentanil citrate on hemodynamic indexes and stress response indexes of Crouzon syndrome children with craniofacial reconstruction. METHODS:60 cases of Crouzon syndrome under-going craniofacial reconstruction were selected from our hospital during Jan. 2010-Jan. 2016,and then randomly divided into group A,group B and group C,with 20 cases in each group. 3 groups were given pump injection of Propofol injection 4-8 mg/(kg·h)for anesthesia induction+Sufentanil citrate injection [group A 0.3 μg/(kg·h),pump injection;group B 0.6 μg/(kg·h),pump injection;group C 1.0 μg/kg,iv,0.5 h/time] for anesthesia maintenance, Cisatracurium besilate for injection 0.1 mg/kg,iv,every 40 min, drug withdrawal 5 min before the end of surgery. The hemodynamic indexes(MAP,HR)and stress response indexes(ACTH,cor-tisol)were observed in 3 groups at different time points as well as the occurrence of ADR. RESULTS:MAP levels of group C at 5 min after skin incision,1 h after operation and immediately at the end of surgery were significantly higher than before anesthesia, while those of group B were significantly higher than group C at same time points. HR of group A at 1 h after surgery and that of group B at 5 min after skin incision and 1 h after surgery were significantly higher than before anesthesias;HR of group B at 1 h after surgery was significantly lower than that of group A,and its HR at 5 min after skin incision and 1 h after surgery were signifi-cantly lower than those of group C. ACTH levels of 3 groups at 5 min after skin incision,1 h after surgery and immediately after the end of surgery were significantly higher than before anesthesia. ACTH levels of group B at 5 min after skin incision,1 h after surgery and immediately after the end of surgery were significantly lower than those of group A and C,and the group A was signifi-cantly lower than the group C at same time points. Cortisol levels of group A at 1 h after surgery,and those of group C at 5 min af-ter skin incision,1 h after surgery and immediately after the end of surgery were significantly higher than before anesthesia. Corti-sol levels of group B at 1 h after surgery were significantly lower than those of group A;cortisol levels of group A at 5 min after skin incision and immediately after the end of surgery and those of group B at 5 min after skin incision,1 h after surgery and imme-diately after the end of surgery were all significantly lower than those of group C. There were statistical significance all above(P<0.05). No obvious ADR was found in 3 groups. CONCLU-SIONS:Pump injection of sufentanil citrate 0.6 μg/(kg·h) can maintain analgesic effect of Crouzon syndrome children with craniofacial reconstruction,can keep hemodynamics sta-ble and effectively inhibit stress response during surgery with good safety.

Forehead Reconstruction with Hydroxyapatite Cement(Mimix(TM)) and the Check Framework

PURPOSE: The purpose of this study is to develop hydroxyapatite cement simplified procedures for reconstruction of craniofacial deformities. Due to its expense and characteristics of quick hardening time, it may be inappropriate for forehead reconstruction or augmentation. Therefore we hear by introduce a more precise, easy and cheap method. The authors report forehead reconstruction with hydroxyapatite cement for a patient who suffered from craniofacial deformity. METHODS: Case report and literature review. RESULTS: A 35 year old man came to us with forehead and temporal area depression. He had a history of brain operations due to traumatic epidural hematoma. A physical exam showed an evidence of right side forehead weakness sign. Authors made RP model of his skull and applied check framework with Kirschner's wires for measuring accurate volume and contour on the depressed right side forehead area on the RP model. After complete exposure of defect area by bicoronary insicion, absorbable plate which applied on skull area was removed. Using three Kirschner's wires, authors made check framework on the right forehead lively and fixed with 2-hole miniplates on the boundary of the defect. After checking asymmetry, hydroxyapatite was applied on check shape framework just above Kirschner's wire. After removing Kirschner's wire, we corrected minimal unbalance and contour with bur. CONCLUSION: Check framework with Kirschner's wire was very convenient and cost saving methods for forehead reconstruction with hydroxyapatite cement.