Comparision of reliability of classifications for idiopathic scoliosis

Für effektives Arbeiten, zur klinischen Entscheidungsfindung und für wissenschaftliche Forschung haben medizinische Klassifikationen eine große Bedeutung. Ziel dieser Arbeit war es deshalb, die neuere Lenke-Klassifikation für idiopathische Skoliosen mit der älteren etablierten Einteilung von King hinsichtlich Zuverlässigkeit und Praktikabilität unter realitätsnahen Bedingungen zu prüfen. Drei Untersucher, alle unerfahren mit der Lenke-Klassifikation und mit unterschiedlicher klinischer Erfahrung in der Skoliosetherapie, klassifizierten unmarkierte Röntgenbilder von 60 Patienten mit idiopathischer Skoliose. Die Blindstudie wurde in 4 zeitlich getrennten Untersuchungsblöcken mit Röntgenbildern von je 15 Patienten durchgeführt, die von jedem Untersucher in beiden Klassifikationen vermessen und bewertet wurden. Die Auswertung erfolgte mit der Multi-Rater-Kappa-Statistik und dem Student-t-Test für unverbundene Stichproben. Beide Klassifikationen zeigten eine geringe bis mäßige Intraobserver- und eine geringe Interobserver-Reliabilität (Interobserver-Kappa: Lenke=0,23, King=0,45). Die Winkelmessung und die Erfahrung der Untersucher haben insbesondere bei der Lenke-Einteilung einen Einfluss auf die Zuverlässigkeit. Die Lernkurve verläuft für diese Klassifikation flacher als bei der Einteilung von King. Die Lernkurve von Untersuchern geringerer Erfahrung steigt steiler an und die Reliabilität ist höher. Mit der Lenke-Klassifikation können idiopathische Skoliosen umfassender und detaillierter beschrieben werden als mit der älteren King-Klassifikation. Damit wird diese Klassifikation den neueren Therapieoptionen besser gerecht. Andere klinisch bekannte orthopädische Klassifikationen zeigten in verschiedenen Untersuchungen ebenfalls lediglich eine geringe bis mäßige Reliabilität. Trotz geringerer Zuverlässigkeit sollte sie deshalb wissenschaftlich und klinisch eingesetzt werden. Unter Reduzierung wichtiger Fehlerquellen mittels teil- oder vollautomatisierten Vermessung und regelmäßiger Anwendung ist eine Steigerung der Zuverlässigkeit zu erwarten und damit ein Einsatz unter klinischen Routinebedingungen denkbar.Medical classifications are neccesary for routine work, for clinical decision making and for scientific research. The intention of this study was therefore to proof the new Lenke-classification for idiopathic scoliosis in comparison with the established classification of King with regard to reliability and practicability. The chosen design of the study attempted to demonstrate as closely as possible the routine clinical setting. Three observers, all unfamiliar with the use of Lenke's classification and with different clinical experience classified non-measured x-rays of 60 patients with idiopathic scoliosis. On each of four independent sessions 15 sets of blinded x-rays were measured manually and classified by the observers for both classifications. Multi-rater-kappa-statistic and the student-t-test for independent spot checks were used to determine the interobserver and intraobserver reliabilities. Both classifications showed a poor to fair intraobserver- and a poor interobserver-reliability (interobserver-kappa coefficient: Lenke = 0.23, King = 0.45). The multiple angle-measurements as well as the experience of the observer influenced the reliability especially for the Lenke-classification. The learning curve of the Lenke-classifcation was shallower than the corresponding curve of King’s classification. The learning curve of observers with less experience showed a steeper course and a better reliability than the curve of the more clinical experienced observers. The Lenke-classification allows a more comprehensive and detailed description of idiopathic scoliosis than the classification according to King. Therefore the Lenke-classification does more justice to modern therapeutic options. Other common orthopaedic classifications showed also only poor to fair interobserver-reliability in previous published studies. Despite poor reliability, Lenke’s classification should be used in science and clinical routine. With reduction of important sources of error by using standardized digital x-rays and automatically measurement and with regular use an increase of reliability can be expected. Under these circumstances the use in daily clinical routine is conceivable

Accuracy of Three-Dimensional Soft-Tissue Prediction Considering the Facial Aesthetic Units Using a Virtual Planning System in Orthognathic Surgery

Virtual surgical planning (VSP) is commonly used in orthognathic surgery. A precise soft-tissue predictability would be a helpful tool, for determining the correct displacement distances of the maxilla and mandible. This study aims to evaluate the soft-tissue predictability of the VSP software IPS CaseDesigner(®) (KLS Martin Group, Tuttlingen, Germany). Twenty patients were treated with bimaxillary surgery and were included in the study. The soft-tissue simulation, done by the VSP was exported as STL files in the engineering software Geomagic Control X(TM) (3D systems, RockHill, SC, USA). Four months after surgery, a 3D face scan of every patient was performed and compared to the preoperative simulation. The quality of the soft-tissue simulation was validated with the help of a distance map. This distance map was calculated using the inter-surface distance algorithm between the preoperative simulation of the soft-tissue and the actual scan of the postoperative soft-tissue surface. The prediction of the cranial parts of the face (upper cheek, nose, upper lip) was more precise than the prediction of the lower areas (lower cheek, lower lip, chin). The percentage of correctly predicted soft-tissue for the face in total reached values from 69.4% to 96.0%. The VSP system IPS CaseDesigner(®) (KLS Martin Group; Tuttlingen, Germany) predicts the patient’s post-surgical soft-tissue accurately. Still, this simulation has to be seen as an approximation, especially for the lower part of the face, and continuous improvement of the underlying algorithm is needed for further development

Plaster Casts vs. Intraoral Scans: Do Different Methods of Determining the Final Occlusion Affect the Simulated Outcome in Orthognathic Surgery?

A virtual occlusal adjustment in orthognathic surgery has many advantages; however, the haptic information offered by plaster casts is missing when using intraoral scans. Feeling the interferences may be helpful in defining the best possible occlusion. Whether the use of a virtual occlusal adjustment instead of the conventional approach has a significant effect on the postsurgical position of the jaws is a question that remains unanswered. This study compares a virtual method to the conventional method of defining the final occlusion. Twenty-five orthognathic patients were included. Bimaxillary and single-jaw orthognathic surgery (mandible only) was simulated. The two methods were compared regarding discrepancies in the simulated postsurgical position of the mandible, measured three-dimensionally using MeshLab (MeshLab 2020.12 3D). An analysis using SPSS revealed no significant differences between the tested methods (p-values: 0.580 to 0.713). The mean absolute discrepancies ranged from 0.14 mm to 0.72 mm, laying within the scope of the clinically acceptable inaccuracies of an osteosynthesis in orthognathic surgery. The lack of haptic information in virtual planning had no relevant influence on the definition of the final occlusion and the simulated postsurgical outcome. However, in individual cases, plaster models might still be helpful in finding the adequate occlusion, especially in the sagittal dimension and in cases of patients with an anterior open bite, but this remains to be tested

Antibiotic prophylaxis and surgical site infections in orthognathic surgery – a retrospective analysis

Abstract Background This study was conducted to determine surgical site infection (SSI) rates and potential risk factors as well as to evaluate antibiotic prophylaxis in orthognathic surgery. Methods This retrospective observational study included patients who received orthognathic surgery. SSIs and their management were assessed for up to one year post-operatively. The applied antibiotic regime and other possible influencing factors (smoking, age, site of infection, drainage, duration of surgery, displacement distances, craniofacial malformations) were assessed. Results In total 291 patient met the inclusion criteria (56.7% female). The mean age at surgery was 25.5 ± 8.5 years. Fifty-four patients (18.6%) were diagnosed with a craniofacial malformation. Relevant previous surgeries were documented in about one quarter of included patients (n = 75). Ninety-two percent of patients (n = 267) received intraoperative single-dose antibiotic prophylaxis. Surgical site infections occurred in 12.4% (n = 36) of patients. There was a significant association between postoperative infections and type of surgery (P = .037) as well as type of drainage (P = .002). Statistical analyses also revealed a higher prevalence of smokers (P = .036) and previous surgically assisted rapid palatal expansion (SARPE) (P = .018) in the infection group. Furthermore, no significant relationships were observed between postoperative infections and various co-factors (i.e. antibiotic regime, age at surgery, gender, associated craniofacial malformations, surgery duration, displacement distances, mandibular setback vs. advancement). Conclusion Low rates of SSIs occurred following an intraoperative single-dose antibiotic regime. None of the SSIs had a significant effect on the final surgical outcome. Present data do not warrant escalation of the antibiotic regimen. Postoperative smoking and capillary drainage should be avoided