3D Surface Measurement for Medical Application—Technical Comparison of Two Established Industrial Surface Scanning Systems

In 3D mapping of flexible surfaces (e.g. human faces) measurement errors due to movement or positioning occur. Aggravated by equipment- or researcher-caused mistakes considerable deviations can result. Therefore first the appliances' precision handling and reliability in clinical environment must be established. Aim of this study was to investigate accuracy and precision of two contact-free 3D measurement systems (white light vs. laser). Standard specimens of known diameter for sphere deviation, touch deviation and plane deviation were tested. Both systems are appropriate for medical application acquiring solid data (<mm). The more complex white-light system shows better accuracy at 0.2s measuring time. The laser system is superior concerning robustness, while accuracy is poorer and input time (1.5-2.5s) longer. Due to the clinical demand the white-light system is superior in a laboratory environment, while the laser system is easier to handle under non-laboratory condition

Lippen-Kiefer-Gaumen-Spalten: Individuelle Analyse der Lippenspalte durch 3-D-Lasertopometrie

Zusammenfassung: Hintergrund: Mit Gipsmodellen und Fotografien ist die dreidimensionale Analyse einer Lippen-Kiefer-Gaumen-Spalte meist nur unzureichend möglich. Ziel der vorliegenden Studie war es daher, die 3-D-Lasertopometrie auf ihre Anwendbarkeit zur dreidimensionalen Weichgewebserfassung bei Patienten mit Lippen-Kiefer-Gaumen-Spalten zu testen. Patienten und Methode: Bei 20 Patienten (3-35 Jahre), die eine einseitige, nicht operierte Lippen-, Lippen-Kiefer- oder Lippen-Kiefer-Gaumen-Spalte aufwiesen, wurde mit einem 3-D-Laserscanner die Gesichtsoberfläche prä- und postoperativ dreidimensional erfasst. Die dabei erzeugten digitalen Datensätze wurden in einer virtuellen Umgebung metrisch analysiert und anhand von Quotienten größenunabhängig wiedergegeben. Sie dienten der Auswahl der Operationstechnik und der Beurteilung des Operationsergebnisses. Ergebnisse: Mit dem 3-D-Laserscanner wurden 3-D-Oberflächen guter Qualität erstellt, die sich im Millimeterbereich ausmessen ließen. Die dreidimensionale Spaltmorphologie konnte in den Datensätzen reproduzierbar mit Landmarks versehen und vermessen werden. Auch die postoperative Symmetrie ließ sich so kontrollieren und objektivieren. Als nachteilig erwiesen sich die relativ lange Messzeit und die Notwendigkeit zur Kombination mehrerer Ansichten. Schlussfolgerung: Das vorgestellte 3-D-Laserverfahren ermöglicht eine präzise dreidimensionale Weichteilanalyse der Lippen- und Nasenregion bei Spaltpatienten. Es eignet sich jedoch nur bedingt für lebhafte Säuglinge und unkooperative Patiente

Quantitative 3D soft tissue analysis of symmetry prior to and after unilateral cleft lip repair compared with non-cleft persons (performed in Cambodia)

OBJECT: The aim of this study was to evaluate the clinical application of three-dimensional (3D) imaging and morphological analysis with subsequent individual therapy planning and postoperative 3D symmetry control in comparison with data from non-cleft persons. DESIGN: This was a prospective study using a 3D surface-imaging and evaluation system in cleft patients and non-cleft persons. The pre- and postoperative 3D facial profiles were recorded from the patients using a 3D laser scanner. The preoperative 3D image was analyzed qualitatively and quantitatively for an individual therapy planning. On the basis of ratios and scores, based on empirical regions of interest, the technique of cleft repair was designed individually. The postoperative result was evaluated regarding symmetry. The surgically created soft tissue shift was defined quantitatively and visualized with vectors. The postoperative symmetry was compared with 3D data from a group of non-cleft persons of the same ethnical group. PATIENTS: Eleven patients (mean age 13.8 years, median 13, minimum 2, maximum 41 years) with either a unilateral isolated cleft lip, a cleft lip and alveolus or a complete unilateral cleft lip, alveolus and palate and 25 non-cleft persons (8 children between 4 and 12 years, 17 adults (9 men, 8 women) between 18 and 50 years). All these persons investigated were Asians of Khmer origin. RESULTS: The analysis permitted quantitative 3D evaluation. The 3D anthropometric data of the non-cleft Khmer persons were collected and named the gold standard of symmetry in this ethnical group. All postoperative 3D images reached symmetrical values within the range of the normal cohort. Soft tissue shifts from pre- to postoperative sites could be visualized. CONCLUSION: A new method for registration was described enabling follow-up registration in patients when growing older. This 3D soft tissue analysis can be a useful tool in quantitative analysis and objective follow-up control in cleft patients. It offers deeper insight into the complex morphology to be treated and could contribute to individualisation of surgical procedures

Preoperative planning and intraoperative navigation in the reconstructive craniofacial surgery

We present a methodology for navigation-aided surgical treatments in the reconstructive craniofacial surgery. Using the case of zygomatic bone repositioning after gunshot wound trauma the whole preoperative planning process and the intra-operative navigation oriented issues are explicitly described. We have focused our attention on the new navigation oriented aspects and procedures which facilitate and enhance the traditional treatment techniques. Many illustrations let better understand the complex technical dependencies between the main elements of this approach. The presented procedures permit more precise planning and performing of the surgical treatment, reducing intra-operative time and improving the post-operative outcome

Silicone moulding for pressure sore debridement.

The radicality of wound debridement is an important feature of the surgical treatment of pressure sores. Several methods such as injection of methylene blue or hydrogen peroxide have been proposed to facilitate and optimise the surgical debridement technique, but none of them proved to be sufficient. We present an innovative modification of the pseudo-tumour technique consisting in the injection of fluid silicone. Vulcanisation of the silicone leads to pressure-sore moulding, permitting a more radical and sterile excision. In a series of 10 paraplegic patients presenting with ischial pressure sores, silicone moulding was used to facilitate debridement. Radical en bloc debridement was achieved in all patients. After a minimal follow-up of 2 years, no complications and recurrences occurred. A three-dimensional (3D) analysis of the silicone prints objectified the pyramidal shape of ischial pressure sores. Our study showed that complete resection without capsular lesion can be easily achieved. Further, it allows the surgeon to analyse the shape and size of the resected defect, which might be helpful to select the appropriate defect coverage technique

Central nervous malformations in presence of clefts reflect developmental interplay

Children with cleft lip and/or cleft palate (CLP) often have additional congenital malformations. The reported incidences are variable and presumed underlying mechanisms are rarely discussed. In this study, 245 CLP patients of a geographically defined population were retrospectively reviewed for additional major malformations and minor anomalies. Malformation incidences in the CLP population were compared to those in a literature-based cohort from the general population. Of the CLP patients, 21% showed either major malformations or minor anomalies. In one-fifth of them a recognized syndrome was identified. Two thirds of the CLP patients with minor anomalies also had major malformations. Major malformations in non-syndomic CLP patients were found with decreasing frequency in the musculoskeletal (5.1%), central nervous (4.2%), urogenital (3.8%) and cardiovascular (3.4%) systems. Malformations in these organ systems and minor anomalies should be ruled out by a specialist. The rise in malformation incidence, when compared to the general population, was highest for organs of ectodermal and ecto-mesodermal origin: central nervous system (13 times), ocular (7 times) and craniofacial system (7 times). The result reflects the close interplay of craniofacial and brain development. textcopyright 2006 International Association of Oral and Maxillofacial surgeons

3D surface measurement for medical application--technical comparison of two established industrial surface scanning systems

In 3D mapping of flexible surfaces (e.g. human faces) measurement errors due to movement or positioning occur. Aggravated by equipment- or researcher-caused mistakes considerable deviations can result. Therefore first the appliances' precision handling and reliability in clinical environment must be established. Aim of this study was to investigate accuracy and precision of two contact-free 3D measurement systems (white light vs. laser). Standard specimens of known diameter for sphere deviation, touch deviation and plane deviation were tested. Both systems are appropriate for medical application acquiring solid data (>mm). The more complex white-light system shows better accuracy at 0.2 s measuring time. The laser system is superior concerning robustness, while accuracy is poorer and input time (1.5-2.5 s) longer. Due to the clinical demand the white-light system is superior in a laboratory environment, while the laser system is easier to handle under non-laboratory conditions

Facial acquisition by dynamic optical tracked laser imaging : a new approach

Three-dimensional capture of the surface of soft tissue is a desirable support for documentation and therapy planning in plastic and reconstructive surgery concerning the complex anatomy of the face, particularly cleft lip and palate (CLP). Different scanning systems are used for capturing facial surfaces. These systems are mostly based on a static linear measuring arrangement. Established systems work on the basis of coded white light or linear laser triangulation and digital stereophotogrammetric approaches. Shadowing effects occur with these devices. These effects may be avoided by a radical new approach first used in automotive industries that employs a mobile, flexible handheld laser scanner with simultaneous registration by optical tracking. The aim of this study was to assess the suitability of this scanner for surgical procedures on the human face in operating theatre. Five babies aged about 3 months with cleft deformities (one CLP, one bilateral CLP, three isolated cleft lips) were captured directly: twice preoperatively, twice postoperatively and twice after 7 days. An industrial standard specimen and two plaster cast masks of CLP babies were taken and subsequently measured to assess reliability and validity of the device. Masks were measured to reflect the complex surface of the cleft deformity. Data evaluation was done with respect to completeness of the data sets, as well as reliability and validity of the system. Missing data caused by shadowing could be avoided in all images. Even complex areas with undercuts could be reproduced completely and precisely with an accuracy in the sub-millimetre range