Study on the criteria for assessing skull-face correspondence in craniofacial superimposition.

Craniofacial superimposition has the potential to be used as an identification method when other traditional biological techniques are not applicable due to insufficient quality or absence of ante-mortem and post-mortem data. Despite having been used in many countries as a method of inclusion and exclusion for over a century it lacks standards. Thus, the purpose of this research is to provide forensic practitioners with standard criteria for analysing skull-face relationships. Thirty-seven experts from 16 different institutions participated in this study, which consisted of evaluating 65 criteria for assessing skull-face anatomical consistency on a sample of 24 different skull-face superimpositions. An unbiased statistical analysis established the most objective and discriminative criteria. Results did not show strong associations, however, important insights to address lack of standards were provided. In addition, a novel methodology for understanding and standardizing identification methods based on the observation of morphological patterns has been proposed.

Prediction of the bone conduction gain curve after partial posterior stapedectomy: the frequency shift concept.

INTRODUCTION: In this article, we present a method able to reasonably predict the bone conduction (BC) gain curve. It provides the advantage of advising patients who will receive little benefit from surgery. MATERIALS AND METHOD: A group of 284 cases is studied in an attempt to verify the poststapedectomy predictability of their characteristic gain curve (CGC) to define a pattern, which indicates the outcome of surgery. For that purpose, the postoperative BC curve has been modeled by fitting a linear regression curve (LRC), which I refer to here as "baseline," into the average audiogram of the 284 cases. RESULTS: Using the average baseline as the predicted postoperative BC audiogram, in 77% of the cases, the predicted CGC is qualitatively comparable to the measured one. DISCUSSIONS: The postoperative baseline can be modeled as a shifting of the average frequency of the preoperative baseline toward higher frequencies. This method is useful to predict the probabilities of having a negative slope in the gain curve after stapes surgery and, therefore, will help in the decision-making process for the indication of surgery and to advise patients on the results they can expect to have. A description of the steps to follow for the application of this method is made available.

Otosclerosis: The effect of stapes surgery on the bone conduction audiogram.

OBJECTIVE: The present study defines the extent of bone conduction loss that can be accounted for by stapes fixation. STUDY DESIGN: Prospective clinical evaluation. SETTING: Tertiary. PATIENTS: Two hundred consecutively operated cases. All patients have been operated by the first author. INTERVENTION: Posterior partial stapedectomy with a platinum-Teflon piston over a perichondral graft. MAIN OUTCOME MEASURES: The bone conduction is studied preoperatively, 1 week, 1 month, and 1 year after surgery. RESULTS: There are at least 3 postoperative gain patterns that change with time, from 1 week to 1 year after surgery. These are patients with maximum gain at 1, 2, and 4 kHz. CONCLUSION: The results suggest that these changes are due to the relation of the preoperative and postoperative oval window transfer functions. The gain in the 3 postoperative audiometric thresholds can be approximated by looking at the characteristics of the preoperative bone conduction audiogram.