Sekou Singare

Fabrication of customised maxillo‐facial prosthesis using computer‐aided design and rapid prototyping techniques

Purpose – This paper describes computer‐aided design (CAD) and rapid prototyping (RP) systems for the fabrication of maxillofacial implant.Design/methodology/approach – Design methods for medical RP of custom‐fabricated are presented in this paper. Helical computed tomography (CT) data were used to create a three‐dimensional model of the patient skull. Based on these data, the individual shape of the implant was designed in CAD environment and fabricate by RP process. One patient with a large mandible defect underwent reconstruction with individual prefabricated implant resulting from initial surgical failure with hand contoured reconstruction plate.Findings – Results shows that the custom made implant fit well the defect. Overall, excellent mandible symmetry and stability were achieved with the custom made implants. The patient was able to eat. There was no saliva drooling after the reconstruction. The operating time was reduced.Research limitations/implications – The methods described above suffer from ...

Rapid prototyping assisted surgery planning and custom implant design

Purpose – This paper aims to describe computer‐aided design and rapid prototyping (RP) systems for the preoperative planning and fabrication of custom‐made implant.Design/methodology/approach – A patient with mandible defect underwent reconstruction using custom‐made implant. 3D models of the patients skull are generated based on computed tomography image data. After evaluation of the 3D reconstructed image, it was identified that some bone fragment was moved due to the missing segment. During the implant design process, the correct position of the bone fragment was defined and the geometry of the custom‐made implant was generated based on mirror image technique and is fabricated by a RP machine. Surgical approach such as preoperative planning and simulation of surgical procedures was performed using the fabricated skull models and custom‐made implant.Findings – Results show that the stereolithography model provided an accurate tool for preoperative, surgical simulation.Research limitations/implications ...

Customized design and manufacturing of chin implant based on rapid prototyping

Purpose – To develop a computer‐assisted prefabricated implant design and manufacturing system to improve the esthetic outcome in chin surgery.Design/methodology/approach – Design methods for medical rapid prototyping (RP) of custom‐fabricated chin augmentation implant are presented in this paper. After a careful preoperative planning based on cephalometric tracing for esthetic assessment, helical computed tomography data were used to create a three‐dimensional model of the deficient mandible. Based on these data, the inner surface of the prosthesis was designed to fit the bone surface exactly. The outer geometry was generated from a dried human mandible to create anatomically correct shape prosthesis. The inner and outer surfaces were then connected, and a solid model resulted. A RP system was used for production of the physical models. The surgical planning was performed using the implants and skull models. The resulting SLA implant is used for the production of a mold, which is used to cast the titaniu...

The effect of latency on bone lengthening force and bone mineralization: an investigation using strain gauge mounted on internal distractor device

BackgroundThe purpose of this study was to investigate the effect of latency on the development of bone lengthening force and bone mineralization during mandible distraction osteogenesis.MethodsDistraction tensions were investigated at different latency period in 36 rabbits using internal unilateral distractor. Strain gauges were prepared and attached to the distractor to directly assess the level of distraction tension during mandible lengthening. The tensile force environment of the mandible of rabbit during distraction was evaluated through in vivo experiments using two gauges.The animals were divided into 3 groups each containing 12 rabbits. Latency periods of 0, 4 and 7 days respectively were observed prior to beginning distraction. The distraction protocol consisted of a lengthening rate of 1 mm once daily for 8 days, followed by a consolidation phase of 2 weeks after which the animals were killed. Biopsies specimens were taken from the distracted area at the end of the distraction period. A non-distracted area of the mandible bone served as control. The specimens were analyzed by scanning electron microscopy to assess the ultrastructural pattern, and the bone mineralization.ResultsThe resting tension acting on the distraction gap increases through distraction. The 7-day latency groups exhibit higher tension then those of 0-day and 4-days latency groups. Quantitative energy dispersive spectral analysis confirmed that immediate distractions were associated with lower calcium and phosphate atomic weight ratio.Conclusionthe latency periods could affect the bone lengthening tension and the bone mineralization process.

Recurrence quantification analysis of EEG predicts responses to incision during anesthesia

The need for assessing the depth of anesthesia during surgical operations has existed since the introduction of anaesthesia, but sufficiently reliable method is still not found. This paper presents a new approach to detect depth of anaesthesia by using recurrence quantification analysis of electroencephalogram (EEG) and artificial neural network(ANN). The EEG recordings were collected from consenting patient prior to incision during isoflurane anaesthesia of different levels. The four measures of recurrence plot were extracted from each of eight-channel EEG time series. Prediction was made by means of ANN. The system was able to correctly classify purposeful responses in average accuracy of 87.76% of the cases.

The Use of Laser Scanner and Rapid Prototyping to Fabricate Auricular Prosthesis

The traditional method to manufacture the auricular prosthesis is based on producing a cast of the patients contralateral ear by direct impression, and sculpting a mirror pattern corresponding to the missing ear. The accuracy and efficiency of prosthesis produced by conventional method absolutely depend on the skill，experience and aesthetic level. An approach that combines laser scanning，reverse engineering (RE) and rapid prototyping (RP) technology for prosthesis fabrication is presented in this paper. As an example related to the design and manufacture of auricular prosthesis, an optical 3D laser digitizer is used to capture the morphology of a human ear. These data are transferred into RE software to create the prosthesis using a computer-aided design (CAD) model, which is directed into the RP machine for the production of the physical model. Finally, the RP model can be used to create the silicone rubber mold to cast the auricular prosthesis. The research results have shown that the integrated method can produce exact-fit prosthesis.

Bispectrum quantification analysis of EEG and artificial neural network may classify ischemic states

This paper examines the relation between the degree of experimentally induced focal ischemia in the left-brain of 24 experimental rats and Higher Order Statistics (HOS) such as the bispectrum and the bicoherence index of scalp EEG recorded at the time of the ischemic event. The aim is to propose the assessment of HOS in non-invasive scalp EEG to facilitate identification and even classification of focal ischemic events in terms of the degree of tissue damage. The latter is achieved by a supervised, multilayer, feed-forward Artificial Neural Network (ANN). The ANN utilizes a back propagation algorithm to classify ischemic states of the brain. The target values used during the training session of the network are the degree of ischemic tissue damage (graded as serious, middle and slight) as assessed by histological and immunhistochemical methods in the brain slice of the experimental animals. The results show that the ANN can correctly identify and classify ischemic events with high precision 91.67% based on HOS measures of scalp EEG obtained during ischemia. These findings may potentially be of great scientific merit, especially due to their possibly very important medical implications: a potential non-invasive method that reliably identifies the presence and the degree of ischemia at the time of its occurrence.