The endopelvic fascia involves a wide array of synonyms which refer to the same structure. It has been referred to as “Lateral pelvic fascia,” “Superior pelvic fascia”, “Parietal pelvic fascia”, “Levator Fascia”, and “Parapelvic fascia” among other synonyms [1]. Currently, there is no established clinical association between histopathological or functional abnormalities of the male endopelvic fascia and the development of lower urinary tract symptoms (LUTS) in patients with benign prostatic hyperplasia (BPH). Our aim was to investigate the mechanical and histopathological properties of the endopelvic fascia.

After obtaining IRB approval, endopelvic fascia specimens were collected from patients (n=10) undergoing robotic laparoscopic radical prostatectomy for the diagnosis of prostate cancer. Two fascia strips (2x1cm) from each side of the pelvis were excised and immediately used for functional studies. Each strip was cut into one centimeter piece for studying. One strip was suspended in organ baths and contractile response to potassium chloride (100 mM), and carbachol (0.01 uM, 1 uM, 10 uM, 20 uM) assessed. The second strip was used for histology. Hematoxylin and Eosin (H&E) and Masson-trichrome staining was performed, and tissue strips assessed elastin fibers, collagen and smooth muscle. Strips were also subjected to mechanical stress strain testing.

Twenty prostatic endopelvic fascia specimens were analyzed from 10 patients. Two out of 20 specimens demonstrated a contractile response to potassium chloride only. No contractile response was observed in the 18 remaining specimens. Histologically, the endopelvic fascia contained predominantly fibrous connective tissue with minor amounts of adipose tissue and rare smooth muscle with occasional presence of arterioles. On tensile testing, the endopelvic fascia exhibited nonlinear behavior, and the nominal stiffness after the toe region was estimated, was 0.765 MPa. Eighteen histopathological samples of the endopelvic fascia were included in our final histology analysis. One sample was excluded as only two large vascular artifacts were present with no fibrous, fatty, or smooth muscle tissue present on the slide. One other sample was excluded because it contained 100% fatty tissue, inconsistent with the definition of fascia. The endopelvic fascia was found to be predominantly fibrous connective tissue with minor amounts of adipose tissue and rare smooth muscle (Figure 1). Most samples (16/18, 89%) were composed of fibrous tissue, involving a median of 95% (IQR=50-95) of total sample. Five samples (27.8%) were found to have fibrous tissue of equal or less than 50% of the total sample. Fat was the second most predominant component with 12 samples (12/18, 66.67%) containing fatty tissue. The median value for the fatty tissue component of the samples was 5% (IQR=0-30) with five samples containing fat as the predominant component. Six samples demonstrated the presence of smooth muscles, with a mean of 10% of the area, while arterioles were found in 10 samples (55.6%).

The male endopelvic fascia appears to be primarily non-contractile tissue as noted by the lack of response to potassium chloride and cholinergic stimulation. Histologically, it is similar to other fascia of the human body. It is therefore unlikely that the endopelvic fascia plays a contractile role in male LUTS, although it may have a mechanical impact on the enlarging prostate considering the high amount of fibrous tissue, which may prevent expansion of the enlarging prostate.

We observed minimal contractile properties in human endopelvic fascia, suggestive of a more passive role in supporting the prostate, and an unclear dynamic role in male LUTS. Further studies are needed to better understand the role of the endopelvic fascia in male LUTS and immunohistology may be useful to determine the presence or absence of alpha-1 receptors.

Herschorn S. Female Pelvic Floor Anatomy: The Pelvic Floor, Supporting Structures, and Pelvic Organs. Rev Urol. 2004;6(Suppl 5):S2-S10.