Age estimation from the sternal end of the fourth rib: a study of the validity of İşcan's Method in Tunisian male population.

The aim of this study was to assess the fourth rib phase İşcan method on a Tunisian sample. One hundred and eight (108) specimens of sternal ends of fourth ribs of Tunisian male population were collected during forensic autopsies performed in the Department of Forensic Medicine and Pathology of the University Hospital Fattouma Bourguiba of Monastir. Two operators, independently, assigned each rib to İşcan's phase. The data obtained by the two operators were analyzed using SPSS 17.0 and MedCalc. The repeatability and accuracy of İşcan method was tested by kappa coefficient (κ), for each operator. Spearman correlation coefficient (R), between estimated İşcan phase and İşcan phase relative to chronological age, was good with values of 0.758 (CI: 0.664-0.828) and 0.717 (CI: 0.611-0.798) for operator 1 and operator 2, respectively. The perfect agreement, between İşcan phase related to chronological age and İşcan phase estimated by both operators, was found for phases fewer than 5. Intra-observer agreement was highest for both operators with kappa value of 0.73 for operator 1 and 0.71 for operator 2. The estimation of the observers fell within one phase from the ideal and there was minimal disparity. A good accuracy between operator 1 and operator 2 was found (κ=0.747, p=0.057). In order to improve the results, we have pooled ages in five new phases. The correlation, between new age groups and İşcan phase estimated by both operators, was moderate. We conclude that İşcan method can be applicable in Tunisian population with a good correlation for age ranges under 39years.