Piriformis Pain
Piriformis
pain is a neuromuscular disorder that occurs when the sciatic nerve is
compressed or otherwise irritated by the piriformis muscle causing pain,
tingling and numbness in the buttocks and along the path of the sciatic nerve
descending down the lower thigh and into the leg.
Diagnosis is often difficult
due to few validated and standardized diagnostic tests, but two have been
well-described and clinically validated: one is electrophysiological, called
the FAIR-test, which measures delay in sciatic nerve conductions when the
piriformis muscle is stretched against it.
The other is magnetic resonance
neurography, a sophisticated version of MRI that highlights inflammation and
the nerves themselves.Some say that the most important criterion is the
exclusion of sciatica resulting from compression/irritation of spinal nerve
roots, as by a herniated disc. However, compression may be present, but not
causal, in the setting of sciatica due to piriformis pain.
The syndrome may
be due to anatomical variations in the muscle-nerve relationship, or from overuse
or strain.
Uncontrolled studies have suggested theories about the disorder,
however a large scale formal prospective outcome trial found that the weight of
the evidence-based medicine is that piriformis pain should be considered as
a possible diagnosis when sciatica occurs without a clear spinal cause.
The need
for controlled studies is supported by studies of spinal disc disease that show
a high frequency of abnormal discs in asymptomatic patients.
Prevention Against Piriformis Pain
If you're a
secretary or psychiatrist, a banker or a bus driver, then sit you must.
My
advice is to take breaks from sitting whenever you can.
And while you are up
and walking around, stretch a little. You can sit in your desk chair and do a
modified gluteal stretch.
If you drive long distances, a gel cushion will make
a spasm less likely. When it comes to exercise, be moderate. Gradually increase
your workout. Don't sit for hours and then go for a brisk mile-long jog that
will increase the possibility of a muscle spasm.
Strengthening
Muscle
strengthening involves working on the hip abductors, external rotators and
extensors. This treatment involves three phases: non-weight bearing exercises,
weight bearing exercises, and ballistic exercises.
The purpose of non-weight
bearing exercises is to focus on isolated muscle recruitment. Ballistic and
dynamic exercises consists of plyometrics.
Failure of conservative treatments
described above may lead to consideration of various therapeutic injections
such as local anesthetics (e.g., lidocaine), Anti-inflammatory drugs and/or
corticosteroids, botulinum toxin (BTX, BOTOX), or a combination of the three.
Injection technique (discussed in above section) is a significant issue since
the piriformis pain is a very deep seated muscle.
A radiologist may assist in
this clinical setting by injecting a small dose of medication containing a
paralysing agent such as botulinum toxin under high-frequency ultrasound or CT
control. This inactivates the piriformis muscle for 3 to 6 months, without
resulting in leg weakness or impaired activity.Rarely surgery may be
recommended.
The prognosis is generally good. Minimal access surgery using
newly reported techniques has also proven successful in a large-scale formal
outcome published in 2005.Failure of piriformis pain treatment may be secondary
to an underlying obturator internus muscle injury.