Piriformis Syndrome Part I and II from Chrio Web

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Piriformis Syndrome: Part I The patient with an unrelenting

sciatica may be suffering with a piriformis syndrome. This syndrome

is considered an entrapment neuropathy caused by pressure on the

sciatic nerve by an enlarged or inflamed piriformis muscle. The

sciatic nerve can be compressed between the swollen muscle fibers and

the bony pelvis.1 Pace and Nagle2 estimated that 45 of 750 cases

referred to their back clinic were treated for this syndrome. They

found that the condition was six times more prevalent in women than

men. Because this syndrome is not common it is often overlooked and

needless surgery may result. Wyant3 states that the functional test

for piriformis syndrome should be a routine part of the physical

examination of all patients presenting with lower spinal backache.

Besides backache, the piriformis muscle contracture and associated

adhesions has been related to radiating pain from the sacrum to the

hip joint over the gluteal region to the posterior thigh,

coccydynia,4 dyspareunia, male impotency5, and oblique axis rotation

of the sacrum with its effect on the total spine up to the atlanto-

occipital region.5 According to Gray6 and Freiberg7 the piriformis

arises from the anterior sacrum between the second to fourth anterior

sacral foramina, from the margin of the greater sciatic foramen and

from the anterior surface of the sacrotuberous ligament, the anterior

sacrospinous ligament and the capsule of the sacroiliac joint.

Freiberg states that the piriformis is the only muscle that bridges

the sacroiliac joint. The piriformis passes through the greater

sciatic foramen (the upper part of which it fills) and inserts by a

rounded tendon into the upper border of the greater trochanter.

Pecian8 examined 130 human specimens to determine the anatomical

relations of the sciatic nerve and the piriformis. He found that in

6.15 percent of the cases the peroneal part of the sciatic nerve

passes between the tendinous parts of the piriformis and a pinching

of the nerve can occur. He found at least five other variations of

the sciatic nerve in relation to the piriformis muscle. He concluded

that when the nerve passed between the tendinous portion of the

piriformis the nerve would more likely be pinched during passive

medial rotation of the thigh which stretches the piriformis, causing

the nerve to be pressed against the extended piriformis. In this

case, resisted testing of the piriformis or ordinary active

piriformis contraction would separate the tendinous portion of the

piriformis surrounding the sciatic nerve and would not compress the

nerve. Mizuguche9 felt that before the piriformis could aggravate the

sciatic nerve there first had to be a preexisting tension on the

sciatic nerve by scarring or arachnoiditis around the nerve roots

secondary to laminectomy or some space-occupying lesion such as

osteoarthritic spurs. He thought that ordinary walking would cause

the piriformis to impinge the shortened nerve. A history of trauma to

the sacroiliac or gluteal region has also been blamed10. The straight

leg raise may be positive due to a contracted piriformis muscle. In a

study by Freiberg and Vinke11 on 10 cadavers it was found that after

raising the leg 25 degrees, the sacrotuberous ligament becomes taut

because of its attachment to the ischial tuberosity and the

hamstrings. A contracted piriformis muscle which originates off the

sacrotuberous ligament also tightened during the SLR. The functional

tests for a piriformis syndrome is naturally based on the function of

the piriformis muscle. One of the main reasons for muscle testing is

to determine if a muscle is painful. Since the piriformis muscle is

an external hip rotator when the hip is in extension and an abductor

when the hip is in flexion,9 external hip rotation should be tested

with the patient supine with the legs hanging off the table edge at

the knees. The patient then attempts to push his leg medially against

resistance. The abduction test for the piriformis could be tested

with the patient sitting facing the examiner. The patient attempts to

abduct the knee against resistance.2 The patient will complain of

pain and possible weakness due to the pain. There may be pain when

the patient sits or squats due to external rotation of the thigh and

hip.5 Passive internal rotation of the thigh with the patient supine

could also aggravate the condition. Pressure on the piriformis by way

of rectal or vaginal examination may reproduce the symptoms.3 A

positive " piriformis sign " due to piriformis contracture may be seen

by the persistent external rotation of one lower extremity when the

patient is supine. A contracted piriformis may result in a functional

short leg.5 The symptoms of female pain during coitus (dyspareunia)

could be due to the externally rotated hips, but female pain and male

impotency is also attributed to piriformis compression of the

pudendal nerve and blood vessels.5 According to Retzlaff et al.,5 on

the side of the piriformis contracture the sacral base will be

rotated anteriorly and examination of a prone patient will show a

deepened sulcus on that side. The apex of the sacrum will appear

posterior on the opposite side at the level of the posterior inferior

illiac spine (oblique axis rotation of the sacrum). This may cause

rotoscoliosis of the lumbar spine and increased lumbar lordosis which

may effect the function of the whole spine. Digital pressure over the

piriformis may refer pain along the complaint area. 1.

Dynamic Chiropractic - June 21, 1991, Volume 09, Issue 13

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Piriformis Syndrome -- Part II Part 1 (June 21, 1991 issue of " DC " )

covered the piriformis syndrome with regards to anatomy, pathology,

symptomatology, and diagnosis. This article will consider the variety

of manual treatments for the condition. The pathology of the syndrome

governs the manual approach. The piriformis is inflamed, spastic,

contains trigger points and, if at all chronic, has connective tissue

adhesions. Pelvic evaluation, especially of the sacrum and iliac

bones, must be performed for specific adjustment of the area.

Palpation for active trigger points in the area is necessary.

Travell1 divides the piriformis in thirds from its origin to

insertion and presses for trigger points. She states that the main

trigger is in the lateral third near the greater tuberosity. The

medial portion of the muscle may refer pain to the buttock and

ischium, but does not refer pain down the lower limb like the gluteus

medius. The lateral third may refer pain to the buttock and posterior

thigh. The patient lies on the pain-free side with the upper thigh

flexed and adducted over the table. The patient may add to the

stretch by resting his arm on the thigh. The stretch and spray method

may be used. In the chronic situation, friction massage may be

applied to the most tender portion in a direction perpendicular to

the fibers. The piriformis may be manually stretched2 by standing on

the opposite side of the prone patient's involved piriformis. The

clinician reaches across and places the heals of his hands at a right

angle to the piriformis, with the arms extended. The doctor leans

with his body weight perpendicular to the long axis of the

piriformis. Within a few minutes the muscle should relax. 3

describes a Nimmo-like technique in which the patient lies on the

normal side with flexion of the hip and knees of the painful side.

The clinician presses his elbow into the tendinous insertion near the

greater trochanter using 40 to 60 pounds of pressure, 8 to 12 times,

for 10 seconds each. The patient should feel rapid relief of pain.

The procedure may have to be repeated two times a week for two to

three weeks. Te Poorten4 has a similar method as except while

he holds pressure on the piriformis he stretches the piriformis by

pulling the leg externally, which internally rotates the hip. Evjenth

and Hamberg5, Muhlemann, and Cimino6 stretches a right piriformis

with the patient supine and the doctor on the patient's right side.

The right hip and knee are flexed about 60 degrees and the right foot

is brought onto the lateral side of the left leg. The DC grips the

ventral/lateral side of the right knee with the right hand and

adducts (stretches the piriformis) the right thigh. The patient is

then asked to isometrically contract laterally against the doctor's

right hand. This position is held for at least seven seconds provided

there is no pain, or with less resistance for 10 to 30 seconds if

there is pain on contraction. The patient is told to relax while the

doctor attempts to further stretch the muscle. If this is too painful

the patient can actively move the thigh more into the stretched

position (adduction). The patient is then asked to resist against

adduction in order to stimulate his antagonists. The new position

should be maintained for at least ten seconds and the entire

procedure repeated a few more times.

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