Practice Patterns of Pancreatic Surgery Within the Military.

INTRODUCTION: Pancreatic surgery is technically challenging, with mortality rates at high-volume centers ranging from 0% to 5%. An inverse relationship between surgeon volume and perioperative mortality has been reported suggesting that patients benefit from experienced surgeons at high-volume centers. There is little published on the volume of pancreatic surgeries performed in military treatment facilities (MTF) and there is no centralization policy regarding pancreatic surgery. This study evaluates pancreatic procedures at MTFs. We hypothesize that a small group of MTFs perform most pancreatic procedures, including more complex pancreatic surgeries. METHODS: This is a retrospective review of de-identified data from MHS Mart (M2) from 2014 to 2020. The database contains patient data from all Defense Health Agency treatment facilities. Variables collected include number and types of pancreatic procedures performed and patient demographics. The primary endpoint was the number and type of surgery for each MTF. RESULTS: Twenty-six MTFs performed pancreatic surgeries from 2014 to 2020. There was a significant decrease in the number of cases from 2014 to 2020. Nine hospitals performed one surgery over eight years. The most common surgery was a distal pancreatectomy, followed by a pancreaticoduodenectomy. There was a decrease in the number of pancreaticoduodenectomies and distal pancreatectomies performed over this period. CONCLUSIONS: Pancreatic surgery is being performed at few MTFs with a downward trajectory over time. Further studies would be needed to assess the impact on patient care regarding postoperative complications, barriers to timely patient care, and impact on readiness of military surgeons.

Practice patterns of hepatobiliary surgery within the military.

BACKGROUND: The purpose of this study is to evaluate the trends of hepatobiliary surgeries performed at military hospitals and to discuss potential implications on resident training and military readiness. While there is data to suggest centralization of surgical specialty services leads to improved patient outcomes, the military does not currently have a specific centralization policy. Implementation of such a policy could potentially impact resident training and readiness of military surgeons. Even in the absence of such a policy, there may still be a trend toward centralization of more complex surgeries like hepatobiliary surgeries. The present study evaluates the numbers and types of hepatobiliary procedures performed at military hospitals. METHODS: This study is a retrospective review of de-identified data from Military Health System Mart (M2) from 2014 to 2020. The M2 database contains patient data from all Defense Health Agency treatment facilities, encompassing all branches of the United States Military. Variables collected include number and types of hepatobiliary procedures performed and patient demographics. The primary endpoint was the number and type of surgery for each medical facility. Linear regression was used to evaluate significant trends in numbers of surgeries over time. RESULTS: Fifty-five military hospitals performed hepatobiliary surgeries from 2014 to 2020. A total of 1,087 hepatobiliary surgeries were performed during this time; cholecystectomies, percutaneous procedures, and endoscopic procedures were excluded. There was no significant decrease in overall case volume. The most commonly performed hepatobiliary surgery was "unlisted laparoscopic liver procedure." The military training facility with the most hepatobiliary cases was Brooke Army Medical Center. CONCLUSION: The number of hepatobiliary surgeries performed in military hospitals has not significantly decreased over the years 2014-2020, despite a national trend toward centralization. Centralization of hepatobiliary surgeries in the future may impact residency training as well as military medical readiness.

The Peripubertal Decline in Makorin Ring Finger Protein 3 Expression is Independent of Leptin Action.

A critical body weight is necessary for pubertal development, an effect mediated in part by leptin. The potential regulation by leptin of Makorin Ring Finger Protein 3 (MKRN3), in which loss-of-function mutations are the most common genetic cause of central precocious puberty, has not been previously explored. In mice, expression of Mkrn3 in the hypothalamic arcuate nucleus is high early in life and declines before the onset of puberty. Therefore, we aimed to explore if leptin contributes to the decrease in hypothalamic Mkrn3 mRNA levels observed in mice during pubertal development. We first used a leptin-deficient (ob/ob) mouse model. Mkrn3 mRNA levels in the mediobasal hypothalamus (MBH), which includes the arcuate nucleus, and in the preoptic area (POA), both showed a significant decrease with age from postnatal day (PND) 12 to PND30 in ob/ob mice in both males and females, similar to that observed in wild-type mice. To further explore the effects of leptin on Mkrn3 expression, we exposed prepubertal wild-type mice to high levels of leptin from age PND9-12, which did not result in any significant difference in Mkrn3 expression levels in either the MBH or POA. In summary, regulation of Mkrn3 expression by leptin was not observed in either the MBH or the POA, 2 hypothalamic sites important for pubertal maturation. These data suggest that the decline in Mkrn3 at the onset of puberty may occur independently of leptin and support our hypothesis that MKRN3 is a bona fide controller of puberty initiation.

MKRN3 inhibits the reproductive axis through actions in kisspeptin-expressing neurons.

The identification of loss-of-function mutations in MKRN3 in patients with central precocious puberty in association with the decrease in MKRN3 expression in the medial basal hypothalamus of mice before the initiation of reproductive maturation suggests that MKRN3 is acting as a brake on gonadotropin-releasing hormone (GnRH) secretion during childhood. In the current study, we investigated the mechanism by which MKRN3 prevents premature manifestation of the pubertal process. We showed that, as in mice, MKRN3 expression is high in the hypothalamus of rats and nonhuman primates early in life, decreases as puberty approaches, and is independent of sex steroid hormones. We demonstrated that Mkrn3 is expressed in Kiss1 neurons of the mouse hypothalamic arcuate nucleus and that MKRN3 repressed promoter activity of human KISS1 and TAC3, 2 key stimulators of GnRH secretion. We further showed that MKRN3 has ubiquitinase activity, that this activity is reduced by MKRN3 mutations affecting the RING finger domain, and that these mutations compromised the ability of MKRN3 to repress KISS1 and TAC3 promoter activity. These results indicate that MKRN3 acts to prevent puberty initiation, at least in part, by repressing KISS1 and TAC3 transcription and that this action may involve an MKRN3-directed ubiquitination-mediated mechanism.