Study design, materials and methods
Consecutive male patients affected by PBNO were considered in the present study. A complete clinical pain evaluation and provocative test were performed to determine a pain diagnosis. During a provocative test, the physician performed a specific physical maneuver in an attempt to recreate the pain. A positive result means the test recreated pain. A combination of many tests are commonly used because a single test is not as sensitive and specific enough to confirm a diagnosis. Pain assessment was mainly focused on pelvic area and lumbar spine. Moreover, potential sources of pain due to nerve entrapments were assessed both clinically and by ultrasound examination. After a clinical examination, only a suspected diagnosis was made and anesthetic blocks under ultrasound guidance were used as subsequent steps for a correct diagnosis of the involved tissue. The anesthetic block test was considered positive if a >50% pain reduction was obtained. Any confounding factor as neurological disorders, diabetes, previous lower limbs and low back surgery were considered as exclusion criteria. A clinical postural assessment was integrated at the end of the pain examination to evaluate if incorrect posture induced stress on muscles, bones, and joints.
72 male patients with PBNO were evaluated. Pelvic pain was reported in a relevant percentage (76%) of the enrolled subjects. Pain onset was extremely variable (12.64±10.87 months, mean±SD). Regional pain distribution involved many different area: lumbar muscles or vertebrae, sacroiliac joint, hip, coccyx, pubic bones and pelvic muscles. Myofascial pain or articular pain was prevalent.
The most common type of pain was nociceptive (85%), while neuropathic pain was found only in 5% of the studied patients with the involvement of iliohyoigastric-ilioinguinal, genitofemoral or pudendal nerve.
A postural impairment characterized by increased lumbar lordosis, abnormal hip elevation, abnormal foot muscle mechanics without morphological abnormalities, sacrum rotation or altered postural control in response to external stimuli was found in more than 60% of the evaluated patients.
Interpretation of results
To our knowledge, no studies have attempted to evaluate the prevalence of pain in PBNO patients. Hypertonic pelvic floor muscles were associated with bladder dysfunction in previous studies [2-3], probably because of compressive forces on pelvic joints and coccyx. All these mechanisms may lead to urinary sphincters hypercontraction and to the development of urinary voiding symptoms without significant morphological alterations. Moreover, in healthy subjects, the activation of the sympathetic nervous system (SNS) usually suppresses pain by descending inhibition of nociceptive transmission in the spinal cord. Otherwise peripheral inflammation and chronic pain can enhance nociceptor activation conducing to spinal facilitation and sensitization. The induced SNS hyperactivation caused by chronic pain, especially if nociceptive, can be implicated in internal sphincter closure and inhibition of the contraction of the bladder wall musculature.