The Impact of Surgical Expertise on the Cost-Effectiveness of Stapes Surgery

INTRODUCTION

Otosclerosis is the primary cause of conductive hearing loss with normal otoscopy. As the condition worsens, certain patients may develop a sensorineural component. Patients with successful surgeries may still need hearing aids, which creates a dilemma for health professionals as there are insufficient data to make informed decisions. This study investigated the influence of the surgeon's proficiency level, individual patient factors (e.g., age at the time of intervention and survival rates), and surgery costs on the cost-effectiveness of stapes surgery.

METHODS

We performed a cost-effectiveness analysis using an adapted Markov model incorporating annual all-cause mortalities. In addition, we introduced sensitivity analyses to address the effects of surgical expertise on adults with bilateral conductive hearing loss due to otosclerosis. A model was developed based on a decision tree with treatment options and complication scenarios for otosclerosis patients undergoing stapes surgery or receiving hearing aids. Annual all-cause mortality was considered. A sensitivity analysis was performed assigned to different training levels ("experts" and "less experienced") to simulate the effects of surgical experience on the cost-effectiveness of surgical outcomes. Successful surgery was defined as closing of the air-bone gap to 10 dB or less. Based on published data, "experts" were simulated with a 93.7% success rate, and "less experienced" were manufactured with a 68.9% success rate.

RESULTS

Stapes surgery provides improved quality of life (QoL) compared to hearing aids with lower cumulative costs up to 87 years of age in the case of "expert" surgeons and up to 78 years of age, when performed by "less experienced" surgeons.

CONCLUSIONS

Primary stapes surgery is highly cost-effective and delivers improved QoL compared to hearing aids with lower cumulative costs. Additionally, undergoing stapes surgical training remains highly cost-effective.

Upregulation of RET induces perineurial invasion of pancreatic adenocarcinoma

Tumor spread along nerves, a phenomenon known as perineurial invasion, is common in various cancers including pancreatic ductal adenocarcinoma (PDAC). Neural invasion is associated with poor outcome, yet its mechanism remains unclear. Using the transgenic Pdx-1-Cre/KrasG12D /p53R172H (KPC) mouse model, we investigated the mechanism of neural invasion in PDAC. To detect tissue-specific factors that influence neural invasion by cancer cells, we characterized the perineurial microenvironment using a series of bone marrow transplantation (BMT) experiments in transgenic mice expressing single mutations in the Cx3cr1, GDNF and CCR2 genes. Immunolabeling of tumors in KPC mice of different ages and analysis of human cancer specimens revealed that RET expression is upregulated during PDAC tumorigenesis. BMT experiments revealed that BM-derived macrophages expressing the RET ligand GDNF are highly abundant around nerves invaded by cancer. Inhibition of perineurial macrophage recruitment, using the CSF-1R antagonist GW2580 or BMT from CCR2-deficient donors, reduced perineurial invasion. Deletion of GDNF expression by perineurial macrophages, or inhibition of RET with shRNA or a small-molecule inhibitor, reduced perineurial invasion in KPC mice with PDAC. Taken together, our findings show that RET is upregulated during pancreas tumorigenesis and its activation induces cancer perineurial invasion. Trafficking of BM-derived macrophages to the perineurial microenvironment and secretion of GDNF are essential for pancreatic cancer neural spread.