Is parotidectomy justified in elderly patients with pleomorphic adenoma? A decision analysis model

PurposeThe value of parotidectomy in older patients is unclear. This study presents a decision model to help resolve this question.Materials & methodsA Markov model with Monte Carlo simulation was used to compare outcomes in patients of different ages with pleomorphic adenoma of the parotid gland treated by surgery or surveillance.ResultsIn 30-year-old patients, surgery conferred a 3.5-year gain in life expectancy whereas in 75-year-olds, it was only 0.74 months. The expected rate of malignant transformation at age 30 years was 6.5% after surgery and 26.5% after surveillance; at age 65, corresponding rates were 0.8% and 10.7%. Sensitivity analysis showed that age was the only parameter that significantly contributed to life expectancy. The benefit of surgery was restricted in older patients.ConclusionOur Markov decision-analysis model suggests that patients older than 65 years with pleomorphic adenoma have a limited survival advantage with surgery compared to surveillance.     

The Association of Helicobacter pylori,Eradication, and Early Complications of Laparoscopic Sleeve Gastrectomy

Obesity Surgery - Laparoscopic sleeve gastrectomy (SG) is a common and effective bariatric surgery, with low postoperative complication rates. It is important to define modifiable risk factors for...     

Knowledge of PCOS in physicians-in-training: identifying gaps and educational opportunities

Abstract

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in reproductive-aged women. A recent study found that many obstetrics and gynecology (ObGyn) practicing physicians are unaware of the Rotterdam criteria recommended for diagnosis. Our objective was to identify gaps in trainee knowledge of PCOS diagnostic criteria and management. An online survey was sent out to US ObGyn physicians-in-training in 2018. The primary outcomes were identification of at least one component of each Rotterdam criteria (Rot-3): (1) oligomenorrhea/amenorrhea, (2) clinical or biochemical hyperandrogenism, and (3) ovarian volume or antral follicle count, and identification of all five components (Rot-5). Secondary outcomes were identification of comorbidities and management of PCOS. Multivariable logistic regression was used controlling for gender, seniority (PGY) status, program type, completion of an REI rotation, and number of PCOS patients seen. 85.4% of 347 trainees completing the survey reported using Rotterdam criteria to diagnose PCOS. However, only 55% identified Rot-3 and less than 10% identified Rot-5. Seniority (PGY4 OR 2.2; 95% CI: 1.2–4.1; p?=?.01) and completion of REI rotation (OR 1.8 95% CI: 1.2, 1.8; p?=?.006) were associated with identifying Rot-3. Similar findings were noted with identifying Rot-5. Our study identified significant gaps in knowledge regarding PCOS, suggesting an urgent need for improving strategies for trainee education to increase patient satisfaction and provide comprehensive care.     

eTEP inferior access with tailored retromuscular dissection for small to mid-sized umbilical hernia repair with or without inguinal hernia: early experience

Hernia - The minimally invasive surgical repair of combined inguinal and ventral hernias often requires shifting from one approach or plane to another. The traditional enhanced-view totally...     

From the Cover: Echolocating bats rely on an innate speed-of-sound reference

Animals must encode fundamental physical relationships in their brains. A heron plunging its head underwater to skewer a fish must correct for light refraction, an archerfish shooting down an insect must “consider” gravity, and an echolocating bat that is attacking prey must account for the speed of sound in order to assess its distance. Do animals learn these relations or are they encoded innately and can they adjust them as adults are all open questions. We addressed this question by shifting the speed of sound and assessing the sensory behavior of a bat species that naturally experiences different speeds of sound. We found that both newborn pups and adults are unable to adjust to this shift, suggesting that the speed of sound is innately encoded in the bat brain. Moreover, our results suggest that bats encode the world in terms of time and do not translate time into distance. Our results shed light on the evolution of innate and flexible sensory perception.

Every organism must reliably sense its environment in order to survive and reproduce (1). Some sensory systems are innate and unalterable (2), allowing for efficient use even by naïve newborn animals (3–5). Others require learning or experience-dependent development—usually during a critical period during ontogeny (6, 7), though sometimes retained through adulthood (8), allowing for adapting sensing to changing environments (9, 10). The ability to accurately estimate distances with sub-centimeter accuracy is a hallmark of bat echolocation (11–13). Bats achieve this accuracy by means of delay-tuned neurons—neurons that are activated by specific call–echo time delays, supposedly encoding target distance (14–19), although it should be noted that some work suggests that the tuning width of delay-tuned neurons might not allow the accuracy that bats exhibit in delay perception (20). Though delay tuning has been shown to be (at least partially) innate at the neural level (21), this has never been tested behaviorally. Namely, when a newborn bat takes off for the first time, does its brain correctly translate time delays into distance?Translating time into distance relies on a reference of the speed of sound (SOS). This physical characteristic of the environment is not as stable as it may seem. The SOS may change considerably due to various environmental factors such as humidity, altitude, and temperature (22). Bats (Chiroptera) are a specious and widely distributed order of highly mobile and long-lived animals. They therefore experience a range of SOSs (with more than 5% variation, see below) between species, among species, and even within the life of a single individual. We therefore speculated that the reference of the SOS may not be innate to allow for the environmentally dependent SOS experienced by each animal.To test this, we examined the acquisition of the SOS reference by exposing neonatal bats to an increased SOS environment from birth (Materials and Methods). We reared two groups of bats from birth to independent flight in two flight chambers: six bats in normal air (henceforth: “air pups”) and five bats in a helium-enriched air environment (Heliox), where the speed of sound was 15% higher (henceforth: “Heliox pups”). Notably, Heliox pups were never active and did not echolocate in non-Heliox environment (Materials and Methods). This 15% shift is higher than the ecological range and was chosen because it is high enough to enable us to document behavioral changes but low enough so as to allow the bats to function (that is, to fly despite the change in air density). In order to feed, the bats had to fly to a target positioned 1.3 m away from their wooden slit roost. Once the bats learned to fly to the target independently (after ca. 9 wk), we first documented their echolocation in the environment where they were brought up, and we then moved them to the other treatment for testing (Materials and Methods). Because bats adjust their echolocation parameters to the distance of the target, before and during flight (23), we used their echolocation to assess the bats’ target range estimates. If the SOS reference is learned based on experience, the bats raised in Heliox should have learned a faster reference, so that when they flew in normal air, they would have perceived the target as farther than it really was. We also ran the same experiments on adult bats to test adult plasticity.     

From the Cover: Bats adjust their mouth gape to zoom their biosonar field of view

Active sensing, where sensory acquisition is actively modulated, is an inherent component of almost all sensory systems. Echolocating bats are a prime example of active sensing. They can rapidly adjust many of their biosonar parameters to optimize sensory acquisition. They dynamically adjust pulse design, pulse duration, and pulse rate within dozens of milliseconds according to the sensory information that is required for the task that they are performing. The least studied and least understood degree of freedom in echolocation is emission beamforming—the ability to change the shape of the sonar sound beam in a functional way. Such an ability could have a great impact on the bat’s control over its sensory perception. On the one hand, the bat could direct more energy into a narrow sector to zoom its biosonar field of view, and on the other hand, it could widen the beam to increase the space that it senses. We show that freely behaving bats constantly control their biosonar field of view in natural situations by rapidly adjusting their emitter aperture—the mouth gape. The bats dramatically narrowed the beam when entering a confined space, and they dramatically widened it within dozens of milliseconds when flying toward open space. Hence, mouth-emitting bats dynamically adjust their mouth gape to optimize the area that they sense with their echolocation system.The ability to actively adjust sensory acquisition is a key feature of almost all sensory systems. A capability to selectively control the sensory “field of view” could have a major impact on sensory perception. It would allow an animal to adjust the amount of acquired information in a task-dependent manner, zooming in on an object of interest and zooming out when a wider sector should be sensed. Many animals can shift their sensory attention (e.g., by changing gaze) or their focal plane (e.g., human vision), but there are no animals that are known to constantly adjust their sensory field of view under natural conditions. Echolocating bats perceive their environment acoustically by emitting ultrasonic pulses and analyzing the received echoes (1). The volume of space that is covered by the sound pulse and therefore, sensed by the bat depends on the emitted beamform—the spatial shape of the emission (2–9). Bats could potentially benefit greatly if they could change the form of their emitted beam in a functional manner, a property usually referred to in engineering as beamforming (10).Jakobsen and coworkers (11) recently summarized some of the reasons why a bat might narrow its biosonar beam. These reasons include (i) focusing sound into a narrower sector to improve the localization of objects, (ii) eliminating undesired echoes from the back or the sides of the bat, and (iii) increasing the sensing range by directing more energy forward. All of these come with a cost of reducing the volume of space that is scanned by the bat. It is, therefore, reasonable to expect that a bat would widen its beam under certain conditions, such as when scanning its surroundings during orientation or navigation.Most echolocating bats emit sound through the mouth (12). The biosonar beam of these bats can be modeled using the “piston model,” which represents a piston-shaped emitter in an infinite baffle (13). According to the piston model (and other emission models as well), a bat can adjust its beam by altering one of two parameters. First, it can change the spectral content of the sound pulse. Increasing the frequency would result in a narrower beam. Several bats that use frequency-modulated pulses seem to use this strategy at the terminal part of an attack on prey (3). Second, the bat can potentially change the aperture of its emitter. By opening its mouth wider, it can narrow the beam and vice versa. However, there is currently no direct evidence that bats change the emitter aperture for beamforming in this way.We studied beamforming in mouth-emitting Bodenheimer''s pipistrelle bats (Hypsugo bodenheimeri) under natural field conditions as well as in a controlled experimental setup. We started by recording and photographing bats as they came to drink at a small desert pond using an array of 12 ultrasonic microphones and a multiflash photography setup. Drinking on the wing requires fine maneuvering skills, which could benefit from active sensory adjustments (14, 15). When descending toward the pond and then ascending from it, the bats had to enter a confined space and then leave it, rapidly changing the degree of clutter around them—the density of nearby objects creating undesired echoes. To deal with these sensory challenges, we predicted that bats will alter their beamform while descending into the confined space or later, ascending out of it using one (or both) of the two mechanisms mentioned above. We used the audio recordings to reconstruct the bats’ emitted beams, and we measured their corresponding mouth gape in the images so that we could assess if and how bats control the beamform. To validate that our results were not a consequence of the drinking per se, we performed a second controlled experiment in which bats flew through a narrow (0.5 × 0.5-m² cross-section) 1.5-m-long tunnel and emerged from it into an open space environment (with less background echoes). We photographed the bats in flight to analyze their mouth gape and simultaneously recorded their echolocation pulses.We found that bats actively adjusted their beam by changing their mouth gape (i.e., the size of the emitter). Bats widened their mouth when entering a more confined cluttered environment, thus dramatically narrowing their beam width, and they narrowed the gape when flying toward the open, thus dramatically widening their beam. Bats that flew through a confined tunnel exhibited the same behavior—widening their mouth gape inside the tunnel and narrowing it when emerging into open space. We argue that this behavior aimed to functionally control the volume of the environment sensed by the bat to improve sensing—decreasing the scanned volume when entering a confined space and increasing it when flying into open space.     

Aesthetic versus surgical success of single dental implants: 1- to 9-year follow-up.

Anterior maxillary implantation is a challenging treatment. The authors examined the aesthetic and surgical success of a single dental implant in the anterior by studying 52 implants with a mean follow-up of 37.5 months. Marginal bone loss (MBL), aesthetic parameters, and examiners' satisfaction from the aesthetic outcome were examined. The total surgical survival and success rates as well as the average examiner's aesthetic satisfaction and success rates are presented. Implantation in the anterior has high surgical survival and success rates, as well as a considerably high aesthetic success rate. The high surgical success and survival rates cannot, however, predict aesthetic success.