Alexander K. Bartella

Color duplex ultrasonography versus handheld Doppler to plan anterior lateral thigh flaps

The anterior lateral thigh flap (ALT) has become increasingly important in reconstructive surgery in the head and neck region. To cope with the problem of anatomical variability in the supplying blood vessels, preoperative evaluation is desirable. Purpose of the study is to compare the most commonly used Doppler devices Handheld Doppler (HD) and Color Doppler Ultrasonography (CDU) for their clinical reliability.

Routine preoperative colour Doppler duplex ultrasound scanning in anterolateral thigh flaps

The anterolateral thigh flap (ALT) is often used to reconstruct the head and neck and depends on one or more skin perforators, which often present with variable anatomy. The aim of this study was to localise and evaluate the precise position of these perforators preoperatively with colour Doppler duplex ultrasound scanning (US). We detected 74 perforators in 30 patients. The mean duration of examination with colour Doppler was 29 (range 13-51) minutes. Adequate perforators and their anatomical course could be detected preoperatively extremely accurately (p<0.001). The mean difference between the preoperatively marked, and the real, positions was 6.3 (range 0-16) mm. There was a highly significant correlation between the accuracy of the prediction and the body mass index of the patient (0.75; p<0.001). Neither the age nor the sex of the patient correlated with the accuracy of the prediction. Colour Doppler duplex US used preoperatively to localise perforators in ALT flaps is reliable and could be adopted as standard procedure.

Hand Perfusion in Patients with Physiological or Pathological Allen's Tests

Background The Allen test (AT) is a widely used clinical tool for the preoperative assessment of sufficient dual vessel hand perfusion although the impact of a pathological AT on tissue perfusion of the hand is not entirely clear. This study reveals perfusion changes of the hand in patients with pathological and physiological AT after terminating the dual blood supply. Methods Patients were distributed into 2 groups (physiological and pathological AT) that each contained 25 members. Perfusion of the thumb, middle, and small fingers was measured with a laser Doppler based (“oxygen‐to‐see” [O2C]) device. A steady state was measured and also values at 1, 3, 5, and 10 minutes after radial occlusion were measured. Results In patients with a physiological AT, only 1 out of 18 values differed significantly from the steady state measurements after 10 minutes, whereas patients with a pathological AT showed significant alterations in 8 out of 18 values. Oxygen saturation of the superficial and deep tissues appeared to be significantly worse in patients with a pathological AT. Conclusion Patients with a pathological AT suffered significantly more from the loss of dual hand perfusion than patients with a physiological AT. Patients with a pathological AT need more time to compensate for the altered perfusion pattern.

Bone regeneration in rabbit calvarial critical-sized defects filled with composite in situ formed xenogenic dentin and biphasic tricalcium phosphate/hyroxyapatite mixture: BONE REGENERATION IN RABBIT CALVARIAL

The purpose of this study was to evaluate bone healing in calvarial defects using two bone graft substitute materials; biphasic beta-tricalcium phosphate/hydroxyapatite in hydrogel (ß-TCP/HA) versus composite non-demineralized xenogenic dentin with ß-TCP/HA mixture. Full thickness critical-sized defects were created bilaterally in 10 New Zealand male rabbits. Seven defects were left empty, six filled with biphasic tricalcium phosphate putty, and seven were filled with composite non-demineralized xenogenic dentin with biphasic tricalcium phosphate. Animals were sacrificed at eight weeks postoperatively and the healing of the biomaterial-filled defects was compared radiographically and by histomorphometry. Micro-computed tomography (μCT) was utilized to analyze the osteogenesis and healing patterns of the defects. Quantitative analysis of volume fraction (%) of the newly formed bone and remaining graft material (FV=filling volume/TV=tissue volume) and mean intensity [HU] in the defects were evaluated. Defects filled with composite dentin with biphasic tri-calcium phosphate showed volume fraction (FV/TV) in the order of 55.81% ± 17.72%, whereas defects filled with only biphasic tricalcium phosphate showed a fraction of 39.84% ± 16.06%, which represent the ratio of remaining graft material and new bone formation to the tissue volume. The empty negative control defects showed a volume fraction of 19.14% ± 8.787%. Histological analysis showed significant percentage increase in bone formation and residual graft with the composite Dentin/ß-TCP group after 8 weeks. The findings suggest that composite xenogenic dentin with biphasic tricalcium phosphate showed improved osteogenesis when compared to biphasic tricalcium phosphate without the addition of non-demineralized dentin.

Classification of the level of mandibular atrophy – A computer-assisted study based on 500 CT scans

OBJECTIVE For the optimal treatment of patients with highly atrophic mandibles, it is required to assess and quantify the extent of atrophy. The classification schemes that are well established today are known to be limited with respect to objectivity and reproducibility. Thus, the aim of the study was to generate a computer-aided method of classification, investigate its applicability in comparison with the established methods, and apply it to a large set of data. MATERIALS AND METHODS Mandibular geometries were segmented from 500 Multislice (MSCT) datasets of atrophic and non-atrophic mandibles and automatically processed to gain virtual images of the mandibular cross-sections. Three different human investigators classified these data according to Cawood and Howells classification scheme. Additionally, a tailored computer algorithm was applied that could work automatically and thus be observer independent. Furthermore, geometrical properties of the mandibles were investigated, statistically analysed, and correlated to the protocolled dental status and to the human and computer-generated classifications. RESULTS Whilst the atrophy classification scheme showed highly significant correlation to the local dimensions of the alveolar ridge, its reproducibility was limited. It was shown that the human classifiers could not objectively classify the mandibular atrophy according to the established methods, with only 60.9% of decisions being unequivocal. The computer-aided method showed similar results to the human investigators. CONCLUSION It is feasible to develop computer-aided procedures for the objective and fully reproducible classification of the level of atrophy. With further research, the established classification scheme may be ameliorated with the aid of computational methods.

Reconstruction of facial soft tissue: comparison between conventional procedures and the facelift technique

We compared the result of replacement using a modified facelift technique with those of other commonly used surgical techniques for the treatment of defects of the soft tissue of the infraorbital and cheek region. We made a retrospective observational study of 86 patients who had defects of the facial soft tissue after excision of malignant tumours. Procedures used for reconstructions included non-vascularised skin grafts, local flaps, facelift technique, and microvascular free flaps, and we evaluated morbidity; duration of hospital stay; the need for, and duration of stay in the intensive care unit (ICU); and functional and aesthetic outcomes. We studied 46 men and 40 women (mean (range) age 71 (8-99) years). We found no significant difference between the methods apart from shorter duration of hospital stay and lower incidence of ectropion in the facelift group. The facelift technique also gave the best aesthetic outcome. However, in defects larger than 60cm2, microvascular free tissue transfer was the only choice. The facelift technique is reliable and safe, and gives excellent aesthetic and functional outcomes, but its use is limited to defects smaller than 60cm2.