Symptoms: Pain
or numbness involving the area between the legs, including
the genitals and occasionally some of the inside of
the thigh. Often only one side is affected. The pain
may be aggravated by sitting.
Diagnosis: The
diagnosis is based on matching the affected area to
the areas supplied by the Pudendal nerve. MR Neurography
imaging can identify entrapments. Injections can confirm
the diagnosis and can help.
What causes the problem?
There are four common sites of nerve entrapment that
can cause a pudendal nerve syndrome. The nerve may
be entrapped as it:
- passes under the piriformis
muscle
- crosses the sacrospinous
ligament and dives under the sacrotuberous ligament
- travels across the obturator
foramen within the Alcox canal
- upon exit from Alcox canal
and branching in the perineal area (between the
legs)
Another cause is entrapment
or irritation of the Impar ganglion on the internal
surface of the coccyx.
How can it be treated?
At the Institute for Nerve Medicine, Dr. Aaron Filler
uses open MRI image guidance to inject anesthetic,
steroid or anti-scarring materials at the various
possible entrapment points. In some cases, injections
such as these help relieve symptoms, but most often
the injections serve to confirm the diagnosis and
pinpoint the cause.
Dr. Filler has also developed
minimal access surgical treatments that are directed
at releasing the nerve entrapments. In some patients,
this involves cutting or trimming the piriformis muscle.
In other patients, the sacrotuberous or sacrospinous
ligaments must be cut or trimmed. Others require dilation
of the Alcox canal.
Overall, surgical treatments
for pudendal nerve entrapment syndrome are new and
success rates are not as good as with other type of
nerve entrapment. However, many patients can expect
significant or complete relief of symptoms from effective
treatment.
