Ovarian tumor in a 12‐year old female with severe hypothyroidism: A case of Van Wyk and Grumbach syndrome

We report a 12‐year‐old female presenting with an abdominal tumor. Diagnostic workup revealed giant bilateral ovarian cysts, severe hypothyroidism as well as an elevation of CA 125. We refrained from ovariectomy, which would be necessary for a malignant tumor, in view of an evident Van Wyk and Grumbach syndrome. The patient promptly responded to L ‐thyroxine with complete regression of all symptoms. Hypothyroidism should be considered in the evaluation of ovarian cysts. Although the Van Wyk and Grumbach syndrome is rare, it is crucial to rule it out in order to avoid unnecessary ovarian surgery when thyroid replacement is completely sufficient. Pediatr Blood Cancer 2009;52:677–679. © 2009 Wiley‐Liss, Inc.     

Review on aspects of artificial tactile feedback in laparoscopic surgery

Since direct manual tissue palpation is not possible in laparoscopic surgery, feedback information on tactile tissue properties is considerably diminished. Restoring part of the surgeon's sense of touch through devices capable of providing artificial tactile feedback (ATF) is an active field of applied research and development.Despite more than two decades of research, technical development of such devices is still basic, and pre-clinical as well as clinical experience is limited. This article provides an overview of the technological aspects of ATF in laparoscopic surgery, gives background information on principles of human perception of related feedback information, and reviews current research attempts in the field of ATF systems in laparoscopic surgery, broken down into three main system components: tactile sensor, display, and data processing.Tactile sensors have been developed to measure tissue compliance, reveal hidden structures or foreign bodies in tissue through measurement of pressure distribution, and to identify and locate arteries by detecting their pulsation. Furthermore, different solutions for presenting tactile data to the surgeon have been developed. Visual and auditory displays are easy to implement into the operating room equipment, while tactile displays still suffer from difficulties concerning their performance and requirements for clinical usability. The role of the data processing system as the linking component in an artificial tactile feedback system has been identified as crucial for effectiveness of the system and easy reception of tactile data by the surgeon.The investigations on theoretical and technological foundations of ATF have led to an extensive database in recent years. An application-driven development approach will likely be a driving factor in the future evolution of this field.     

Dielectric measurement of cerebral water content using a Network Analyzer

Abstract

At present, no practical method exists for monitoring the progression and severity of cerebral oedema in a clinical setting on a continuous basis. In search for such a method[ we investigated the electrical characteristics of cerebral tissue at microwave frequencies to quantify cerebral oedema. The dielectric constants of normal and oedematous canine cerebral white matter were measured using a Network Analyzer and then compared to the tissue's water content In additioni, salt infiltration and time elapsed after excision of the tissue were examined to determine their effects on the measurements.

The water content and dielectric constant of the white matter were linearly related (correlation coefficient; r = 0.903), comparable to results obtained with a Time Domain Reflectometer in previous research. The Network Analyzer, however; is a more robust measurement device and, because of this, can potentially be used for long term measurements. Further, it was found that neither an increased tissue salt content nor the amount of time after excision of the tissue significantly affected the results. This indicates that the dielectric constant of cerebral white matter is mainly a function of the tissue's water content