Brian P. Jacob, David C. Chen, Bruce Ramshaw, Shirin Towfigh (eds.) - The SAGES Manual of Groin Pain-Springer International Publishing (2016)

11. Groin Pain Etiology: Pudendal Neuralgia
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innervation supplied by the pudendal nerve. It is neuropathic in nature
and is exacerbated by sitting [ 4 ]. The gradual progression in pain for
patients usually is minimal in the morning and progressively worsens
throughout the activities of daily living, becoming most severe in the
evening. Classically, most patients will note they have less pain sensation
when sitting on the toilet seat in comparison to a chair.
Almost all patients with pudendal neuralgia have pain with intercourse
and postcoital dyspareunia. Patients often state that it is so severe
they will refrain from having intercourse altogether, which negatively
affects their partners as well. Along with dyspareunia, common complaints
also include pain with bowel movements, urination, or sexual
arousal, as discussed above.
Physical Examination The physical examination is extremely important
in order to rule out other possible causes of pain. Common findings
among patients with pudendal neuralgia include pelvic floor muscle
spasm and pain on pelvic examination; therefore, it can be difficult to
determine any underlying nerve injury until the spasms are treated [ 5 ].
Among patients with pudendal neuralgia, the physical examination
should always confirm pain within the dermatome supplied by the
pudendal nerve. In patients with pudendal nerve entrapment, there will
be tenderness over the sacrospinous ligament just medial to the ischial
spine. Palpation of this area precipitates a tingling sensation commonly
known as Tinel’s sign.
Ancillary Testing As noted in Table 11.1 , pudendal nerve motor terminal
latency ( PNMTL ) testing may help determine nerve conduction
and the integrity of the nerve [ 6 ]. Electrical impulses are applied transvaginally
or transrectally using a pudendal electrode (St. Mark’s) on the
tip of the examiner’s finger. Increased conduction time signifies damage
to the nerve. It is a nonspecific test, as it does not determine the cause or
the level of the injury. Also, the results of the study have been shown to
have wide range, as the length of this nerve can be variable [ 7 ]. The
value of this testing therefore remains controversial.
Quantitative sensory threshold testing and mapping have been used
for the diagnosis of other peripheral nerve disorders, but have not been
validated for the pudendal nerve [ 8 ]. These tests gauge the ability to
discern between hot and cold temperatures and also between two pressure
points. Compressed nerves lose the ability of fine discrimination.
Magnetic resonance imaging ( MRI ) of the pelvis is superior to other
imaging modalities of the pelvis, as it can determine abnormalities of
the muscles and soft tissue in great detail [ 9 ]. Higher resolution 3 T