Scrotal thermoregulatory model and assessment of the impairment of scrotal temperature control in varicocele.

Varicocele is defined as the pathological dilatation of the pampiniform plexus and scrotal veins with venous blood reflux. Varicocele may impair scrotal thermoregulation and spermatogenesis, even when present in asymptomatic forms. In this study, we use the control system theory to model scrotal thermoregulation in response to a standardized cold challenge in order to study the functional thermal impairment secondary to varicocele. The proposed model is based on a homeostatic negative feedback loop, characterized by four distinct parameters, which describe how the control mechanisms are activated and maintained. Thermal infrared images series from 49 young patients suffering from left varicocele and 17 healthy controls were processed. With respect to healthy controls, left varicocele patients presented higher basal scrotal temperature and faster recovery of the left hemiscrotum. The model indicated that varicocele alters local heat exchange processes among cutaneous layers and inner structures. The estimated model parameters help in the assessment of the scrotal thermoregulatory impairment secondary to the disease.

Infrared thermographic evaluation of temperature modifications induced during implant site preparation with cylindrical versus conical drills.

BACKGROUND: A few studies have investigated the influence of drilling on bone healing. Many factors have been reported to influence temperature rise during surgical preparation for implant placement: drill geometry, drilling depth, sharpness of the cutting tool, drilling speed, pressure applied to the drill, use of graduated versus one-step drilling, intermittent versus continuous drilling, and use or not of irrigation. PURPOSE: The objective of this study was to quantify the temperature changes in cortical bone and at the apical portion of the drills during implant site preparation with a cylindrical implant drill versus a conical implant drill. MATERIALS AND METHODS: Two implant drill systems were evaluated in vitro using bovine femoral cortical bone. The two implant drill systems evaluated in this study were system A (a cylindrical drill with triple twist drills) (Bone System, Milano, Italy) and system B (a conical drill with quadruple twist drills) (Bone System). Site preparation began, and the temperature of the cortical bone and at the apical portion of the drill was measured by the infrared thermography. RESULTS: The mean temperature produced in the cortical bone during implant preparation was 31.2 ± 0.5°C for the cylindrical drills and 29.1 ± 0.6°C for the conical drill. The mean temperature produced in the apical portion of the drill during implant site preparation was 32.1 ± 0.7°C for the cylindrical drill system and 29.6 ± 0.6°C for the conical drill. Statistically significant differences were found in the temperature measurements in the cortical bone in the two groups (p < .05). A statistically significant difference was observed for the temperature measurements in the apical portion of the drill in the two groups (p < .005). DISCUSSION: The model system used in this work was able to evaluate the temperature in the cortical bone and in the apical portion of the drills; the temperature modifications in the apical portion of the drill seemed to be correlated to the drill geometry. The results of the present study showed that drill geometry seems to be an important factor in heat generation during implant site preparation. CONCLUSION: The drill geometry could explain the increased temperature in the apical portion of the drill.

Thermal imaging of cutaneous temperature modifications in runners during graded exercise.

In this paper we used high-resolution thermal imaging to visualize the human whole body anterior cutaneous temperature (T(c)) variations in well-trained runners during graded exercise. Fifteen male volunteers underwent a graded treadmill test until reaching their individual maximal heart rate. Total body T(c) decreased as the subjects started the exercise. Thighs and forearms exhibited the earliest response. A further T(c) diminution occurred with the progress of the exercise. At the exercise interruption, T(c) values were in average 3-5 degrees C lower than at baseline. T(c) increased during recovery from exercise. Forearms and thighs exhibited the earliest increase, followed by total body T(c) increase. Thermal imaging documented the presence of hyperthermal spots (occasionally tree-shaped) due to the presence of muscle perforator vessels during baseline and recovery, but not during exercise. The results we report indicate that thermal infrared imaging permits the quantitative evaluation of specific cutaneous whole body thermal adaptations which occur during and after graded physical activity. Thus providing the basis for evaluating local and systemic cutaneous blood flow adaptation as a function of specific type, intensity and duration of exercise, and helping to determine the ideal conditions (in terms of environment and apparel) in which physical activities should be conducted in order to favor thermal regulatory processes.

Assessment of the effects of varicocelectomy on the thermoregulatory control of the scrotum.

Infrared functional imaging was successfully used to assess restoration of the normal thermal control of the scrotum after surgical treatment of varicoceles. The technique may be used to study the relationship between impaired scrotal thermoregulation and spermatogenesis.