Fig. 3.1
Associations between commonly observed elements of male sexual dysfunction, pelvic floor dysfunction, and pelvic pain
3.2 Anatomy and Physiology of the Male Pelvic Floor
Until recently, the terminology used to describe the anatomy and function of the male pelvic floor has varied across health care disciplines . In an attempt to standardize terminology, The International Continence Society has proposed the following definitions: the pelvic floor is a compound structure that encloses the bony pelvic outlet, while the term PFMs refers to the muscular layer of the pelvic floor [15]. These terms are henceforth used accordingly.
The male pelvic floor consists of several tissue layers, but there has been some nomenclature inconsistency in the literature. Varied names and boundaries have been utilized to describe PFMs and divisions between the muscle layers, a problem that may complicate health care provider communication. Stoker has suggested that the pelvic floor should be thought of as four principal layers : the endopelvic fascia, muscular diaphragm, perineal (or urogenital) diaphragm, and superficial transverse perinei [16]. DeLancey has recognized the peritoneum as the most cranial part of the pelvic floor and the skin of vulva, scrotum, and perineum as the most caudal [17]. Some health care providers believe the puborectalis should be regarded as a component of the external anal sphincter versus the more widely accepted notion that it is a component of the levator ani muscle group [18]. In the end, however, it is well appreciated that male pelvic floor function relies on complex and dynamic relationships between muscles, fascia, ligaments, bone, nerves, and vascular supply and that in men, as it is similarly found in women, these multiple pelvic structures play a crucial role in normal urinary, bowel, and sexual function.
The anatomy and function of the pelvic floor can be best understood when its relationship to the surrounding bony architecture is considered. The bony pelvis is a ring structure composed of the sacrum, and right and left innominate bones. Each innominate bone consists of three parts: the ilium, ischium, and pubis. The pelvic cavity is divided into the false (greater) and true (lesser) pelvis by the pelvic brim [19]. The pelvic brim (or inlet) extends from the promontory of the sacrum, along the arcuate line of the ilium, pectineal line and pubic crest. The coccyx is also part of the bony pelvis, and consists in most people of five coccygeal bones, which articulate with one another and with the sacrum.
The male PFMs attach to the interior of the pelvic ring and thereby serve to stabilize its joints when the muscles are active. The male PFMs extend from the dorsal aspect of the pubic symphysis and pubic rami anteriorly to the coccyx posteriorly. They attach laterally to the ischial tuberosities, interior surfaces of the illia, and to the arcus tendineus levator ani (ATLA) —a tendinous arc that extends from the posterior aspect of the pubic arch anteriorly to the ischial spine posteriorly, in the right and left sides of the pelvis. The male PFMs also function to support the internal organs of the abdomen and pelvis and promote voluntary closure of the urethral and anal sphincters in men [20]. In women PFMs also provide tone to the vaginal vault.
In order to provide optimal mechanical advantage for their functions, the male PFMs are arranged in a dome-shaped sheet that contains a complex network of mostly striated muscle, which provide cover for the entire pelvic cavity [18, 21]. The varied functions of the male pelvic floor are achieved via coordinated activity that involves the full range of contraction, relaxation, and active lengthening, or stretch, of their fibers.
PFMs are often subdivided into superficial and deeper components, each with particular functions [19]. The convention adopted by pelvic rehabilitation practitioners is to describe the PFMs in terms of three layers, progressing from superficial (caudal) to deep (cranial) within the pelvic floor [22]. For the remainder of the description of pelvic floor anatomy , this convention will be adopted.
The structure of the male pelvic floor is shown in Fig. 3.2. The first, most superficial layer of muscle, or the superficial perineal pouch in men, consists of the bulbocavernosus, (the bulbospongiosus in women), the ischiocavernosus, the superficial transverse perineal, and the external anal sphincter. These superficial PFMs function in men to provide urethral and anal closure and maintain continence, as well as to expel the urethral contents. The superficial layer also plays a significant role in penile tumescence and rigidity during erection, as will be discussed later.
Fig. 3.2
The male pelvic floor, lithotomy view. (1) bulbospongiosus m. (2) ischiocavernosus m. (3) deep transverse perineal m. (4) superficial transverse perineal m. (5) pubococcygeus m. (6) obturator internus m. (7) perineal body (8) external anal sphincter (9) anococcygeal ligament (10) coccyx (11) ischial tuberosities (12) sacrotuberous ligament. With permission courtesy of Jeff Gibson, www.malepelvicfloor.com
The second layer of the PFMs, or the urogenital diaphragm , consists of the deep transverse perineal, the sphincter urethrae, and the compressor urethrae. This second layer of PFMs adds further support to urethral closure during increased intra-abdominal pressure. This second layer has fascial connections into the deep abdominal musculature, and thereby also plays a role in stabilization of the pelvic and lower lumbar joints during movement.
The third most cranial layer of the male PFMs, called the pelvic diaphragm, extends from the dorsal aspect of the pubic symphysis to the coccyx and from the interior surface of one ilium to the other [19]. The pelvic diaphragm consists of the pubococcygeus—which is comprised of the pubourethralis (pubovaginalis in women), the puborectalis, and the iliococcygeus. The pubococcygeus and iliococcygeus collectively are termed the levator ani, as contraction of this deep layer of PFMs serves to elevate the anal sphincter. This deepest layer of the PFMs is most responsible, along with the peritoneal fascia, for support of the pelvic organs. The tonic activity of the pelvic diaphragm prevents the supportive ligaments of the pelvic organs from becoming over-stretched by constant tension [23]. The tonic activity, combined with the minimal elasticity of the endopelvic fascia, gives the pelvic diaphragm its characteristic dome shape. In the presence of pathology, such as low-tone PFD or ligamentous laxity, the pelvic diaphragm appears more basin shaped versus the usual dome shape [16].
The puborectalis is also responsible for controlling the anorectal angle, and thereby maintaining anal continence when it is contracted, and allowing for evacuation of the bowels when relaxed. The deepest layer of the pelvic floor also consists of the ischiococcygeus, or the coccygeus muscle. The coccygeus is not strictly considered to be part of the PFMs, as it does not share it its functions of continence, organ support, or sexual function. Contraction of the coccygeus muscle deviates the coccyx to the ipsilateral side.
As previously mentioned, the relationship between the puborectalis and levator ani muscles remains debatable. Traditionally it has been thought that the puborectalis constitutes a major component to the levator complex. Using MRI, Stoker demonstrated that the puborectalis contributes to both the levator ani and external anal sphincter [16]. However, recent developmental and histological evidence indicate otherwise, suggesting it may be more closely associated with the external anal sphincter [18]. On the other hand, the external anal sphincter is innervated by the inferior rectal branch of the pudendal nerve, whereas the puborectalis and the cranial aspect of the remainder of the levator ani are innervated by the nerve to the levator ani directly [24]. The disparate innervation may imply evolutionary difference between the puborectalis and the levator ani muscles.
The urogenital diaphragm is another component of the male pelvic floor whose structure is debated in the literature. Sometimes referred to as the triangular ligament or the perineal membrane, the urogenital diaphragm occupies the area between the pubic symphysis and ischial tuberosities, lying external and inferior to the pelvic diaphragm [19]. The urogenital diaphragm is composed of a strong muscular membrane that separates the superficial perineal pouch from the upper pelvis and does not constitute a true diaphragm. Historically, the urogenital diaphragm has been described as a tri-layer structure made up of the deep transverse perinei with a superior and inferior fascia [16]. However, recent work suggests that the presence of the deep transverse perinei and superior fascial layer are questionable and that the urogenital diaphragm may represent a single musculofascial layer [25].
Finally, pelvic innervation is fundamental to normal male sexual, urinary, and bowel functions. The muscles of the pelvic floor are innervated by sympathetic, parasympathetic, and somatic nerve fibers. The three types of nerve fibers allow for careful regulation of PFMs including those responsible for erection, emission, ejaculation, urination, and defecation. The hypogastric, pudendal, and levator ani nerves all participate in these sexual, urinary, and bowel functions. Coordinated contraction of the bulbospongiosus muscle is carried out by input from the pudendal nerve (from spinal nerves S2–4), which is necessary for emission and ejaculation. Emission is mediated through the sympathetic nervous system via the hypogastric nerve innervated by preganglionic neurons in the intermediolateral and medial gray nuclei [26, 27]. There is evidence from animal models that contractions of the bulbospongiosus and ischiocavernosus muscles are important for expulsion of seminal fluids and for increased hardness/engorgement of the glans penis [28]. Another study found that contractions of the levator ani in rats act in coordination with the bulbospongiosus to augment penile erectile hardness and that muscle activity is tightly coordinated through somatic innervation during copulation [29]. The role of the PFMs in erection and ejaculation in humans will be discussed further in the remainder of this chapter.
While there still remains discrepancy in terminology and controversy about exact anatomic detail, this review highlights the complex network at play within the male pelvis. A comprehensive understanding of pelvic floor anatomy and physiology is crucial to appreciate the intricacies of normal male sexual, urinary, and bowel function.
3.3 The Pelvic Floor in Male Erectile Function
Normal erectile function includes the ability to obtain an erection sufficiently rigid for vaginal penetration , and ability to sustain this erection long enough to complete sexual intercourse. ED is said to be present when there is a consistent inability to either obtain and/or maintain an erection sufficient for completion of sexual intercourse [30]. Estimates of prevalence of ED range in various countries from 9 to 40 % of men by age 40, and generally increase by 10 % in each decade of life thereafter [3, 31].
The observation that there is a voluntary skeletal muscular component to erectile function and that contractions of the superficial PFMs , in particular, the bulbocavernosus (BC) and ischiocavernosus (IC), are necessary for full penile rigidity, is over a century old [32]. The 1909 edition of Gray’s Anatomy referred to the IC as the “erector penis” [33]. Since that time, human and animal models have demonstrated that these two muscles are activated during sexual activity, especially thrusting. It is now understood that there exists a vascular phase and a muscular phase to the formation of a full erection, which correspond to glans tumescence and supraphysiologic erectile rigidity [34].
Contractions of the ischiocavernosus muscles participate in the process of erection by inducing suprasystolic intracavernosal pressures [35, 36] and reducing venous return [7]. The IC also stabilizes the erect penis [37]. Contraction of the BC contributes to engorgement of the glans penis and corpus spongiosum [37], causes increased intraspongiosal pressure [38], and slows venous drainage of blood from the corpora cavernosum, by compressing the deep dorsal vein of the penis [20, 38]. Contraction of the BC and IC can improve erection by increasing maximum inflow pressure, as well as likely compensate for veno-occlusive dysfunction. The degree to which these muscles in the most superficial pelvic floor can participate in penile erection depends on the functional strength and coordination of these muscles. Indeed, voluntary pelvic floor activation has been shown to be more efficient in men who have full erectile function than in those with ED [7–9]. As well, efficiency of maximal pelvic floor contraction was negatively correlated with age in a group of impotent men [8].
A recent study suggested that in order to provide resistance for the IC muscle to increase its strength, a rehabilitation program should include voluntary contractions of this muscle during a state of erection [36]. In this way, the intracavernosal pressure in the corpus cavernosum provides the needed resistance to challenge the IC and induce a training effect. This study also indicated that application of electrical stimulation simultaneously with voluntary contraction may also improve the strength and efficiency of IC contractions. Vibration was applied to stimulate erection, in order to activate the IC muscle reflex contraction via stimulation of mechanoreceptors in the glans.
Rehabilitation of PFM function has long been suggested as an important component of treatment for ED [39–41], and has been found to be effective at improving erectile function [9, 34, 36, 42, 43]. PFM exercise appears to be especially beneficial in men with mild or moderate veno-occlusive dysfunction [34, 44, 45]. Claes noted that in younger fully potent men only a single systolic injection of blood is needed to achieve both tumescence and rigidity. In contrast, he hypothesized that in the group of men who have penile corporal fibrosis and/or reduced relaxation of the corporal smooth muscle and therefore corporal veno-occlusive dysfunction, voluntary contractions of the IC muscle may provide the needed increase in intracavernosal pressure to establish closed hydraulic system needed to maintain penile erection.
Abnormally high pelvic floor tone has been suggested as a cause of ED. Spasm of the PFMs can provide extrinsic compression that impairs pudendal arterial inflow [5, 6]. This is the basis for the current understanding of the high prevalence of ED among individuals with CPPS, as will be discussed later.
3.4 The Pelvic Floor in Ejaculatory Function
The mechanics of ejaculation reflect a muscular event that occurs simultaneously with involuntary contraction of the prostate gland, involuntary closure of the bladder neck, and involuntary relaxation of the urethral sphincter muscles. Just as voluntary contraction of the BC functions to empty the distal urethra at the end of micturition, involuntary contraction of the BC muscle expels contents from the urethra during ejaculation [37, 43]. Shafik also demonstrated that rhythmic contractions of the external urethral sphincter during ejaculation may act as a “suction–ejection pump,” sucking the seminal fluid into the posterior urethra while relaxed and ejecting it into the bulbous urethra upon contraction [46].
Strong BC muscle contractions will increase maximal engorgement of the corpus spongiosum, increase urethral pressure and facilitate ejaculation of prostatic and seminal vesicle fluid. Strong BC contraction may also enhance and intensify orgasmic pleasure during ejaculation. PFM training may therefore optimize ejaculatory volume, force, and intensity of sexual climax [37].
The International Society of Sexual Medicine has defined PE as “ejaculation within a minute” [47]. More broadly, PE can be said to include ejaculation beyond the man’s control, sooner than he would like, for his own and his partner’s sexual satisfaction. PE is the most common male sexual dysfunction [1, 2], and it negatively affects the enjoyment of sexual activity for many men and their partners. This condition also impacts negatively on the self-image and sex lives of many men and adversely affects their relationships with their partners [48]. In a large multinational survey, the prevalence of PE was found to be 23 % overall among participants from the USA, Germany, and Italy [1].
The exact mechanism controlling the ejaculatory reflex, whether by contraction or relaxation of the BC and IC muscles, is not well defined [20], though Pastore suggested that active perineal muscle control could inhibit the ejaculation reflex through intentional relaxation of the bulbo- and ischiocavernosus muscles, which are active during arousal [49].
Several therapies are available to treat PE, with mixed results. Behavioral therapies include precoital masturbation, increasing sexual activity frequency, and manual or physical maneuvers intended to delay ejaculation. The squeeze technique described by Masters and Johnson [50] makes use of the bulbocavernosus reflex, in which sustained pressure is applied to the glans penis causing contraction of the BC muscle and, as a result, diminished ejaculatory urgency. Stopping the movement of intercourse and performing a sustained PFM contraction can also function to defer the urgency of ejaculation, serving as an “internal squeeze” without manual pressure [37].
Pharmacologic strategies include precoital use of topical anesthetic creams to the penile shaft, precoital use of selective serotonin reuptake inhibitors (SSRI), precoital use of opioids such as tramadol, and precoital use of phosphodiesterase type 5 inhibitors [47].
Pelvic floor rehabilitation has been shown to improve control with delaying ejaculation and allowed significant increases in intravaginal ejaculatory latency times [51, 52] in men with PFD [53]. Pelvic floor strategies have also proven to be a viable alternative to use of the SSRI dapoxetine [49]. Most of these studies were conducted with patients who had seen little or no benefit from other interventions.
The application of pelvic floor rehabilitation to the treatment of PE is beginning to be established as a principle, although studies have not yet clarified the features of a specific treatment protocol. Whether emphasis should be on strength, control, or relaxation is not yet well understood but, as is the case with any pelvic dysfunction, treatment should be tailored to individual findings.
3.5 Chronic Prostatitis/Chronic Pelvic Pain Syndrome
3.5.1 Epidemiology
Prostatitis is a common and often debilitating condition that affects millions of men worldwide. The National Institutes of Health Consensus Committee has divided prostatitis into categories I, II, IIIA, and IIIB. Categories III indicate CP. Category IIIA indicates that leukocytes are present in expressed prostatic fluid, and Category IIIB indicates that these markers are absent. This condition is often called chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS). CP/CPPS is characterized by pain in the pelvis, abdomen, or genitals, and lower urinary tract symptoms of an obstructive or irritative nature, without evidence of recurrent urinary tract infection [54, 55]. Discomfort or pain accompanying ejaculation or afterward are common, as are concurrent sexual dysfunctions, especially ED and PE [5, 10, 11, 14]. CP/CPPS has a prevalence rate of 2–16 % for men in various populations in different regions of the world [11, 56, 57].
CP/CPPS is strongly associated with both sexual dysfunction and PFD and can significantly impact quality of life and relationships of men with this condition [58]. Emphasizing the health status impact of this condition, Wenninger et al. used the Sickness Impact Profile, a generic health status measure, in patients with CP and demonstrated that the mean scores were within the range of scores reported in the literature for patients suffering from other illnesses, such as myocardial infarction, angina, or Crohn’s disease [59].
3.5.2 CP/CPPS and Sexual Dysfunction
The most common sexual dysfunctions reported in men with chronic pelvic pain are ED, ejaculatory pain, and PE [5]. Aubin et al. found that men with CP/CPPS have higher rates of sexual dysfunction—lower desire, diminished erectile and orgasmic function, and more frequent pain associated with orgasm and/or ejaculation—than men without pelvic pain [10]. In this study, some of these variables were also related to demographic factors such as age and marital status. However, erectile function as measured by the Brief Sexual Functioning Questionnaire (BSFQ) varied inversely with pain status, independent of these demographic factors. CP/CPPS may also affect female partners who are in relationships with those men who are afflicted. In one case–control study, when compared with controls, men with CP/CPPS had greater rates of sexual dysfunction and depression [11]. When these men and their partners were compared with control couples, the sexual function of men with CP/CPPS was also significantly associated with that of their female partners, who reported higher rates of dyspareunia.
3.5.2.1 CP/CPPSand Erectile Dysfunction
ED is especially common in men with CP/CPPS. Prevalence rates of ED in men with CP/CPPS have been reported in the literature to range from 15 to 40.5 % [5]. The prevalence of ED in a survey of Finnish men with chronic pelvic pain was 43 %, and decreased libido was 24 % [12]. In a survey of 296 Malaysian men with CP/CPPS, 72 % reported sexual dysfunction, which was defined as ED and/or ejaculatory difficulty [13]. The presence of sexual dysfunction in participants of this study was also correlated with greater symptom severity and worse quality of life. A 2002 cross-sectional survey conducted in Singapore also reported that men with CP/CPPS had worse erectile function as measured with the IIEF assessment tool and worse quality of life than men without prostatitis [14].
The higher-than-normal prevalence of ED among individuals with CP/CPPS may be explained by changes in peripheral arterial function in this group. A case–control study involving men with CP/CPPS demonstrated that this group was more likely to have evidence of arterial stiffness associated with nitric oxide-mediated vascular endothelial dysfunction compared to asymptomatic controls [54]. The authors suggest that this may be related to increased autonomic vascular tone associated with pain-induced chronic stress. In addition, they note that vascular endothelial dysfunction may be a contributing factor to the pathophysiology of the chronic muscle spasm and pain experienced by men with chronic pelvic pain. A subgroup of the cases in this study were treated with pelvic floor physical therapy and quercetin supplementation, and 3 out of 4 of these demonstrated improved systemic peripheral arterial function, as well as reduction of their CP/CPPS symptoms [60]. Another possible explanation for the high rate of ED among men with chronic pelvic pain is related to the presence of abnormally high resting PFM tone, a hallmark of CPPS. As mentioned earlier, elevated pelvic floor tone is thought to be a possible impediment to normal erectile function. One likely mechanism for this association is the potential obstruction of arterial inflow to the penis by extrinsic compression from surrounding musculature [5].
3.5.2.2 CP/CPPS and Premature Ejaculation
PE is another sexual dysfunction commonly found in men with chronic pelvic pain. In one study, the prevalence of sexual dysfunction, which included ED and/or PE, was higher in men with CP/CPPS (49 %) than in the general population, and was negatively correlated with age and duration of CP [61]. A study of Turkish men also showed a significantly higher rate of PE (77.5 %) among a group of men with CP compared with controls (10 %) [62].
One study found a high rate of signs of prostatic inflammation (56.5 %) and chronic prostatic infection (47.8 %) among a group of men with PE [63]. These authors note that the impairment of sensory feedback occurring immediately before orgasm is widely considered the pathogenetic mechanism of PE [64]. Based on their findings, they postulate that the presence of prostatic inflammation may alter sensation and thus the ejaculatory reflex.
Related posts:
Overactive Pelvic Floor: Gastrointestinal Morbidities
Female Voiding Dysfunction
Medical Therapies for the Treatment of Overactive Pelvic Floor
Female Genital Pain and Penetration Disorders
A Tale of Two Pain States: The Integrative Physical Therapy Approach to the Overactive Pelvic Floor
Complementary and Alternative Therapies for the Overactive Pelvic Floor
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