Article: Endoscopic assessment of free flap perfusion in the upper aerodigestive tract using indocyanine green: A pilot study.Christian Stephan Betz, Sven Zhorzel, Hilmar Schachenmayr, Herbert Stepp, Christoph Matthias, Colin Hopper, Ulrich Harréus[show abstract] [hide abstract]
ABSTRACT: INTRODUCTION: Malfunction of microvascular anastomoses is the main reason for free-flap failures. The aim of this investigation was to prove the feasibility of endoscopic free-flap perfusion measurements in the upper aerodigestive tract (UADT) using indocyanine green (ICG). METHODS: Twenty-five patients undergoing free-flap reconstruction of the UADT were included. At least three ICG angiographies (0 h, 24 h and 72 h) were performed per participant. The sequences were subjectively judged online. The data were subsequently analysed, the results compared to clinical outcome and a survey with clinical staff (n = 21) performed. RESULTS: All 25 flaps survived. The ICG angiographies were tolerated well, showing a delayed fluorescence gain in transplanted tissue compared to surrounding but comparable final maximum fluorescence intensities. Four surgical revisions (two for a true and two for a false indication) could be additionally investigated. The two flaps with a real perfusion compromise showed fluorescence Indices (relative fluorescence maxima of transplant vs. surrounding) of 33% and 37%, whereas these values lay above 60% for all other examinations (including those two flaps that were revised for a false indication). The survey showed that ICG angiography leads to a better discrimination of well- and malperfused flaps compared with conventional inspection. CONCLUSION: In this small level IIb study, it was possible to prove the feasibility of endoscopic ICG angiography in patients with free-tissue transfer to the UADT. In difficult situations, it seems a welcome adjunct to conventional screening and might aid in the decision whether to revise a clinically suspect flap.Journal of Plastic Reconstructive & Aesthetic Surgery 02/2013; · 1.49 Impact Factor
Article: Optical coherence tomography in the assessment of suspicious oral lesions: An immediate ex vivo study.[show abstract] [hide abstract]
ABSTRACT: Optical coherence tomography (OCT) is an evolving optical technology that is capable of delivering real-time, high-resolution signatures of tissue. The purpose of this immediate ex vivo prospective clinical study was: (1) to assess the sensitivity and specificity of OCT on biopsy material in identifying potentially malignant and malignant oral lesions, (2) to determine the inter-observer agreement in the analysis of specific image parameters, and (3) to find out the oral epithelial thickness for different pathology groups. This prospective study involved 125 suspicious oral lesions from 125 patients. The lesions were surgically biopsied and subjected to OCT in the immediate ex vivo phase. Two independent readers (surgeon and pathologist) examined the OCT images and assessed several cellular features including keratin layer, epithelial layer, basement membrane and lamina propria, and recorded their findings using special OCT reading score. The sensitivity, specificity and accuracy of OCT to predict "the future need for surgical biopsy in case of any similar lesion" were calculated. The epithelial thickness was also measured. The degree of agreement between the two readers was recorded. The pathological diagnosis revealed that the majority of lesions demonstrated microinvasive carcinomas (n=43). Forty-one had different degree of dysplasia. Benign oral lesions were less common and included 22 keratosis, 11 non-specific lesions, 6 mucocels and 2 papillomas. Optical coherence tomography achieved a sensitivity of 85% and a specificity of 78% in the assessment of oral potentially malignant and malignant disorders. The positive and negative predictive values were 86.5% and 77.5%, respectively. The accuracy was 82% and the kappa coefficient of inter-observer agreement was 0.72 on "the need for biopsy". OCT imaging of oral lesions provided valuable information on the oral epithelial thickness. This study proposes that OCT can accurately identify wide spectrum of oral tissue pathologies. Further studies can assess the role of OCT in evaluating and guiding surgical biopsies and monitoring disease.Photodiagnosis and photodynamic therapy 02/2013; 10(1):17-27.
Photodiagnosis and photodynamic therapy 09/2012; 9(3):284-5.
Christian S Betz, Winrich Rauschning, Evgueni Ph Stranadko, Mikhail V Riabov, Valery N Volgin, Volker Albrecht, Nikolay E Nifantiev, Colin Hopper[show abstract] [hide abstract]
ABSTRACT: In a previous publication we showed that mTHPC-PDT (Foscan®-PDT) is an effective treatment of basal cell carcinomas (BCCs) in "difficult to treat" locations and presented optimized treatment parameters to reduce costs and side effects. Now we present long-term results of the same study population. Following PDT of a total of 460 BCCs in 117 subjects, the patients/lesions were followed-up for a mean duration of 42 (range: 2-72) months. Two patients dropped out of follow-up; 13 patients died of unrelated causes. Recurrences were treated either by repeated PDT or other established methods. The sustained clearance rate was 93.7% and the overall treatment success rate was 90.7%. Kaplan-Meier analysis revealed an estimated recurrence free fraction of patients at 5 years of 95.1%, 92.4%, 85.1%, and 74.0% for the four different photosensitizer dose groups (0.06-0.15, 0.05, 0.04, and 0.03 mg/kg). High-risk lesions (recurrences, thickness >3 mm) recurred more often than low-risk ones, and recurrences mostly (>50%) occurred during the first year of follow-up. Long-term outcomes of high-dose (0.06-0.15 mg/kg) and reduced-dose (0.05 mg/kg) Foscan®-PDT in "difficult to treat" BCCs compare favorably with other methods, even in high-risk lesions (recurrent and/or thick lesions). A recommended combination of treatment parameters for low-dose therapy seems to be: 0.05 mg/kg Foscan®, 24 hours drug-light interval (DLI), fluence ≥40 J/cm(2) . Prospective randomized studies are needed to look into low-dose mTHPC-PDT of BCCs in more detail and to directly compare it with other treatments.Lasers in Surgery and Medicine 07/2012; 44(7):533-40. · 2.75 Impact Factor
Article: Analysis of the compatibility of dental implant systems in fibula free flap reconstruction.[show abstract] [hide abstract]
ABSTRACT: As a result of major ablative surgery, head and neck oncology patients can be left with significant defects in the orofacial region. The resultant defect raises the need for advanced reconstruction techniques. The reconstruction in this region is aimed at restoring function and facial contour. The use of vascularised free flaps has revolutionised the reconstruction in the head and neck. Advances in reconstruction techniques have resulted in continuous improvement of oral rehabilitation. For example, endosteal implants are being used to restore the masticatory function by the way of prosthetic replacement of the dentition. Implant rehabilitation usually leads to improved facial appearance, function, restoration of speech and mastication. Suitable dental implant placement's site requires satisfactory width, height and quality of bone. Reconstruction of hard tissue defects therefore will need to be tailored to meet the needs for implant placement.The aim of this feasibility study was to assess the compatibility of five standard commercially available dental implant systems (Biomet 3i, Nobel Biocare, Astra tech, Straumann and Ankylos) for placement into vascularised fibula graft during the reconstruction of oromandibular region.Radiographs (2D) of the lower extremities from 142 patients in the archives of the Department of Radiology in University College London Hospitals (UCLH) were analysed in this study. These radiographs were from 61 females and 81 males. Additionally, 60 unsexed dry fibular bones, 30 right sided, acquired from the collection of the Department of Anatomy, University College London (UCL) were also measured to account for the 3D factor.In the right fibula (dry bone), 90% of the samples measured had a width of 13.1 mm. While in the left fibula (dry bone), 90% of the samples measured had a width of 13.3 mm. Fibulas measured on radiographs had a width of 14.3 mm in 90% of the samples. The length ranges of the dental implants used in this study were: 7-13 mm (Biomet 3i), 10-13 mm (Nobel biocare), 8-13 mm (Astra Tech), 8-12 mm (Straumann ) and 8-11 mm (Ankylos).This study reached a conclusion that the width of fibula is sufficient for placement of most frequently used dental implants for oral rehabilitation after mandibular reconstructive procedures.Head & Neck Oncology 06/2012; 4:37. · 3.13 Impact Factor