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American Journal of Obstetrics and... Jan 2020Without cesarean delivery, obstructed labor can result in maternal and fetal injuries or even death given a disproportion in size between the fetus and the maternal... (Review)
Review
Without cesarean delivery, obstructed labor can result in maternal and fetal injuries or even death given a disproportion in size between the fetus and the maternal birth canal. The precise frequency of obstructed labor is difficult to estimate because of the widespread use of cesarean delivery for indications other than proven cephalopelvic disproportion, but it has been estimated that at least 1 million mothers per year are affected by this disorder worldwide. Why is the fit between the fetus and the maternal pelvis so tight? Why did evolution not lead to a greater safety margin, as in other primates? Here we review current research and suggest new hypotheses on the evolution of human childbirth and pelvic morphology. In 1960, Washburn suggested that this obstetrical dilemma arose because the human pelvis is an evolutionary compromise between two functions, bipedal gait and childbirth. However, recent biomechanical and kinematic studies indicate that pelvic width does not considerably affect the efficiency of bipedal gait and thus is unlikely to have constrained the evolution of a wider birth canal. Instead, bipedalism may have primarily constrained the flexibility of the pubic symphysis during pregnancy, which opens much wider in most mammals with large fetuses than in humans. We argue that the birth canal is mainly constrained by the trade-off between 2 pregnancy-related functions: while a narrow pelvis is disadvantageous for childbirth, it offers better support for the weight exerted by the viscera and the large human fetus during the long gestation period. We discuss the implications of this hypothesis for understanding pelvic floor dysfunction. Furthermore, we propose that selection for a narrow pelvis has also acted in males because of the role of pelvic floor musculature in erectile function. Finally, we review the cliff-edge model of obstetric selection to explain why evolution cannot completely eliminate cephalopelvic disproportion. This model also predicts that the regular application of life-saving cesarean delivery has evolutionarily increased rates of cephalopelvic disproportion already. We address how evolutionary models contribute to understanding and decision making in obstetrics and gynecology as well as in devising health care policies.
Topics: Animals; Biological Evolution; Cephalopelvic Disproportion; Cesarean Section; Female; Gait; Hominidae; Humans; Parturition; Pelvic Bones; Pelvimetry; Pelvis; Pregnancy; Pubic Symphysis; Selection, Genetic
PubMed: 31251927
DOI: 10.1016/j.ajog.2019.06.043 -
Seminars in Interventional Radiology Dec 2011The pelvic course of the ureter with its close proximity to the iliac artery, pelvic viscera, and other structures predispose to fistula formation. Surgical management...
The pelvic course of the ureter with its close proximity to the iliac artery, pelvic viscera, and other structures predispose to fistula formation. Surgical management of lower urinary tract fistulas is difficult and often ineffective. Nonvascular lower urinary tract fistulas can be managed by urinary diversion with percutaneous nephrostomy to allow for fistula healing. If this fails, ureteral embolization can be very effective; however, this should be preceded by careful evaluation and discussion with the patient as this intervention results in irreversible ureteral occlusion necessitating a diverting nephrostomy catheter indefinitely. A ureteroarterial fistula is a distinct entity compared with nonvascular fistulas with a different approach to management; it can be managed by exclusion of the fistula by endovascular placement of a stent graft across the arterial component of the fistula.
PubMed: 23204637
DOI: 10.1055/s-0031-1296081 -
World Journal of Radiology Apr 2016Transperineal ultrasound is an inexpensive, safe and painless technique that dynamically and non-invasively evaluates the anorectal area. It has multiple indications,... (Review)
Review
Transperineal ultrasound is an inexpensive, safe and painless technique that dynamically and non-invasively evaluates the anorectal area. It has multiple indications, mainly in urology, gynaecology, surgery and gastroenterology, with increased use in the last decade. It is performed with conventional probes, positioned directly above the anus, and may capture images of the anal canal, rectum, puborectalis muscle (posterior compartment), vagina, uterus, (central compartment), urethra and urinary bladder (anterior compartment). Evacuatory disorders and pelvic floor dysfunction, like rectoceles, enteroceles, rectoanal intussusception, pelvic floor dyssynergy can be diagnosed using this technique. It makes a dynamic evaluation of the interaction between pelvic viscera and pelvic floor musculature, with images obtained at rest, straining and sustained squeezing. This technique is an accurate examination for detecting, classifying and following of perianal inflammatory disease. It can also be used to sonographically guide drainage of deep pelvic abscesses, mainly in patients who cannot undergo conventional drainage. Transperineal ultrasound correctly evaluates sphincters in patients with fecal incontinence, postpartum and also following surgical repair of obstetric tears. There are also some studies referring to its role in anal stenosis, for the measurement of the anal cushions in haemorrhoids and in chronic anal pain.
PubMed: 27158423
DOI: 10.4329/wjr.v8.i4.370 -
Diagnostic and Interventional Imaging Nov 2017Endometriosis is a common gynecological disorder defined by the presence of endometrial tissue outside the uterus. It is the most common cause of chronic pelvic pain and... (Review)
Review
Endometriosis is a common gynecological disorder defined by the presence of endometrial tissue outside the uterus. It is the most common cause of chronic pelvic pain and typically affects the ovaries, uterine ligaments, peritoneum, tubes, rectovaginal septum and bladder. It may, however, be found at various extrapelvic sites, including the perineum, liver, pancreas, lung or even the central nervous system, and in such cases, diagnosis may be quite challenging. Even though definitive diagnosis requires laparoscopy, preoperative identification of endometriosis is important not only to differentiate it from other diseases with similar clinical presentations but also, for accurate presurgical mapping, since complete removal of all endometriotic foci is critical for the effective treatment of the patient's symptoms. Ultrasound is performed initially, but magnetic resonance imaging (MRI) is increasingly being used, particularly when sonographic findings are unclear, when deep pelvic endometriosis is suspected or when surgery is planned, as it provides better contrast resolution and a larger field of view compared to ultrasound. In this article, we will discuss distinctive MRI appearances of endometriotic foci and we will review common and uncommon locations of endometriosis within the body, in an attempt to familiarize radiologists with its wide spectrum of manifestations.
Topics: Abdominal Wall; Adnexa Uteri; Cell Transformation, Neoplastic; Diagnosis, Differential; Endometriosis; Female; Gastrointestinal Diseases; Humans; Magnetic Resonance Imaging; Nervous System Diseases; Pelvis; Peritoneum; Thoracic Diseases; Urinary Bladder Diseases; Uterus; Viscera
PubMed: 28652096
DOI: 10.1016/j.diii.2017.05.009