Combined Decompression of Pudendal and Inferior Cluneal Nerves for Entrapment Neuralgias Using Transperitoneal Robotic Laparoscopy: Feasibility and Our 4 Step Technique.

OBJECTIVE: To demonstrate the feasibility of a combined decompression of pudendal and inferior cluneal nerves for entrapment syndrome using a transperitoneal robotic laparoscopy. DESIGN: Demonstration of our 4-step technique with narrated video footage. SETTING: Pudendal and inferior cluneal neuralgias caused by an entrapment syndrome are both responsible for perineal pain [1]. Although more precise data are lacking, these 2 neuralgias are frequently associated. Failure of surgical pudendal nerve decompression in the early 2000 has driven to discover the entity of a potential entrapment syndrome of the posterior cutaneous nerve of the tight and its inferior cluneal branches between the ischium bone and the sacrotuberous ligament [2]. The corresponding neuralgia is responsible for a neuropathic pain to a more posterior part of the perineum and the thigh, without any neurovegetative symptom. In case of failure of medical treatment, surgery can be proposed using an invasive open transgluteal approach as a standard treatment [3-5]. INTERVENTIONS: Transperitoneal robotic laparoscopy for a mini-invasive releasing of both pudendal and inferior cluneal nerves, following a 4-step technique: 1. Opening of the peritoneum between the external iliac vessels and the umbilical ligament 2. Dissection of the internal iliac and pudendal arteries up to the pudendal nerve 3. Section of the sacrospinous ligament and release of the pudendal nerve 4. Section of the sacrotuberous ligament and release of the inferior cluneal nerve CONCLUSION: Previously, pudendal and inferior cluneal neuralgias have been managed with an invasive open transgluteal surgery. Here, we demonstrate the feasibility of a mini-invasive transperitoneal robotic laparoscopy, with a standardized 4-step surgical technique. VIDEO ABSTRACT.

Stochastic and Deterministic Models for the Metastatic Emission Process: Formalisms and Crosslinks.

Although the detection of metastases radically changes prognosis of and treatment decisions for a cancer patient, clinically undetectable micrometastases hamper a consistent classification into localized or metastatic disease. This chapter discusses mathematical modeling efforts that could help to estimate the metastatic risk in such a situation. We focus on two approaches: (1) a stochastic framework describing metastatic emission events at random times, formalized via Poisson processes, and (2) a deterministic framework describing the micrometastatic state through a size-structured density function in a partial differential equation model. Three aspects are addressed in this chapter. First, a motivation for the Poisson process framework is presented and modeling hypotheses and mechanisms are introduced. Second, we extend the Poisson model to account for secondary metastatic emission. Third, we highlight an inherent crosslink between the stochastic and deterministic frameworks and discuss its implications. For increased accessibility the chapter is split into an informal presentation of the results using a minimum of mathematical formalism and a rigorous mathematical treatment for more theoretically interested readers.