Piriformis Syndrome and the Gait Cycle System
by Jeffrey D. Olsen, DC
Warning! If your patient is already lying on the treatment table before you enter the room, you could be missing important clues. Evaluating your patient’s gait can provide valuable information, especially in slowly responding cases or other special cases. Many of the chronic or recurring cases of pelvic, hip, or low back complaints are directly associated with gait imbalances. Take time to watch your patients walk around.
When patients don’t respond to our Chiropractic care as expected, often there is an underlying collapse in the postural platform formed by the feet. A recent study found that “there are small, but important, inter-segmental movements of the spine during gait.”1 Abnormal motion initiated by excessive or restricted joint interactions of the feet and lower extremities will eventually interfere with the normal inter-segmental motions and lead to pain syndromes.
Specifically, I would like to address the common clinical findings of excessive foot flare, externally rotated femur, and piriformis muscle contracture. This triad of findings is often found in the patient with generalized hip and sacroiliac pain and dysfunction that might even include classic findings of sciatic nerve irritation. The same patient might enjoy temporary relief from symptoms following pelvic adjustments and/or the combination of stretching and massage. However, all too often, the underlying cause of the dysfunction is altered foot biomechanics, especially the hyperpronated foot.
When patients turn to Chiropractic care for pain relief, few, if any, expect an area of their anatomy, distant from the perceived pain, to be at fault. However, in seven of 10 patients with back pain, postural fatigue and spinal strain cause their discomfort.2 We find that the ultimate cause of pain could originate in any tissue or joint involved in the Kinetic Chain. This is the exact scenario that, with time, produces the symptoms we are discussing.
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As you observe your patient walking, take note of unilateral toeing out. Toe-out is an adaptive muscular response to the biomechanics of hyperpronation. Hyperpronation (loss of medial longitudinal arch integrity) during stance phase accentuates walking with foot flare, which should normally be in the range of 10 to 20 degrees. Associated with excessive pronation and foot flare is marked wear along the lateral border of the heel. The excessive lateral heel wear is a good indicator of the chronicity and extent of the deformation. Excessive lateral heel wear also indicates the need to properly support the medial longitudinal arch.
Even with the patient prone, the toe-out or foot flare will remain until corrected. Furthermore, this position gives a great view of any lateral heel wear.
There are three natural arches of the foot. Their strength and function depend on the proper alignment of bones and the support of the ligamentous tissues—plantar fascia and bone-to-bone ligaments. The most common structural misalignment of the lower extremity is excessive pronation, affecting the medial arch primarily. Whenever there is compromise of the arch structures or the supporting soft tissues, the postural foundation is adversely affected.
In addition to the normal degrees of foot pronation during the stance phase of the gait cycle, there are a series of coupled motions that result in medial rotation of the entire lower limb and pelvis. With hyperpronation, this torqueing is accentuated. The increased rotational forces are transmitted into the pelvis and hip region. One of the primary antagonists to this excessive medial rotation is the piriformis muscle.
The piriformis has its origin on the second through fourth anterior segments of the sacrum and on the sacrotuberous ligament. The muscle travels anterior and inferior, through the greater sciatic foramen, as it passes superior and posterior to the femoral head. The muscle inserts on the greater trochanter, allowing the muscle to laterally rotate the thigh and assist in the tracking of the femoral head within the acetabulum.3
The following have been proposed as possible mechanisms in which irritation of the piriformis muscle leads to apparent or actual sciatic neuritis. First, in many cases, branches forming the sciatic nerve first pass through the belly of the piriformis muscle. Spasm and hypertrophy can physically irritate the nerve.4 Second, when irritated, the piriformis can release inflammation byproducts that have been shown to be chemical irritants.5
With the patient prone, efforts to place the thigh into internal rotation will be limited both by the contracture of the muscle and by reproduction of the patient’s symptoms. Externally rotating the femur accentuates the subluxated position of the femur and should result in shortening of the reactive leg, during functional leg checks.
Treatment involves contacting the posterior aspect of the greater trochanter and adjusting with an anterior and slightly inferior line of drive.
Obviously, the long-term solution is to remove the underlying irritation by supporting the feet. Foot Levelers’ Gait Cycle System™ (GCS) is the appropriate solution. This is the only system designed to absorb the shock of the foot striking the ground, to specifically support the three arches within normal ranges of motion, and to facilitate neuromuscular control for coordinated gait.
Our discussion of hyperpronation leading to a piriformis syndrome is only one example of the possible consequences of poorly supported arches. Remember that excessive motion in the feet will irritate the weak links further up the Kinetic Chain. A custom orthotic will help your patient’s foot adapt to its environment, regardless the circumstances.
Not only does the orthotic support the arches of the foot, but it also reduces the transmission of shock into the spine. Pathological shock occurs when normal walking on ridged surfaces exacerbates irritated structures. Force generated at heel strike can reach five to seven times body weight, with the musculoskeletal system itself absorbing a significant percentage of the total, under normal conditions.6 With Zorbacel® in the heel and Propacel™ in the forefoot, orthotics with GCS contain unique viscoelastic materials to absorb shock and provide a boost, whatever part of the foot first strikes the ground.
Chiropractic adjustments of the spine improve proprioceptive input by normalizing joint alignment and muscle tonus. Furthermore, because the feet contain approximately one quarter of all the body’s joints and, therefore, a concentration of proprioceptive fibers, it becomes logical to conclude that support of the postural foundation using custom-made orthotics will enhance the balance of our patients who need it most. In fact, this was the basis for recent research involving Foot Levelers’ custom orthotics, published in JMPT.
Drs. Stude and Brink showed that experienced golfers, after wearing Foot Levelers orthotics daily for a period of six weeks, showed improvements in balance and proprioception. This becomes significant given the fact that experienced golfers would be expected to have maximized their coordination and balance abilities as it relates to the game of golf, and yet they did show improvement. The results were obtained through functional tests involving single and double-leg stances, with and without the use of sight.7
Obviously, not every one of our patients is a candidate for orthotic therapy, but about four out of five adult patients older than 40 can benefit from orthotics. By this time, the effects of walking and standing on hard surfaces, ligament laxity (age-related or post-partum), and repetitive microtraumas have often contributed to significant plastic deformation in the feet. Prescribing the orthotics with GCS provides highly dynamic and adaptive responses for an increase level of mobility and stability. If you are watching your patients come and go, you’ll know when they need it.
About the Author
Dr. Jeffrey D. Olsen is a 1996 Presidential Scholar and summa cum laude graduate of Palmer College of Chiropractic. He has been in private practice, with his two brothers/partners, since 1997, in Roanoke, Virginia. In addition to his practice, Dr. Olsen has instructed as an adjunct faculty member at the College of Health Sciences in Roanoke, teaching Anatomy and Physiology in the Physician Assistant department.
1 Sychewska M, Oberg T, Karlsson D. Segmental movements of the spine during treadmill walking with normal speed. Clin Biomech 1999; 14:384-388.
2 Brunarski DJ. Chiropractic biomechanical evaluations; validity in myofascial low back pain. J Manip Physiol Ther 1982; 5(4):155-161.
3 Moore KL. Clinically Oriented Anatomy. Baltimore: Williams & Wilkins, 1982:346.
4 Cox JM. Low Back Pain: Mechanism, Diagnosis and Treatment, 5th ed. Baltimore: Williams & Wilkins, 1990.
5 Steiner C et al. Piriformis syndrome: pathogenesis, diagnosis, and treatment. J Am Osteopath Assoc 1987; 87:318.
6 Voloshin AS, Burger CP. Interaction of Orthotic Devices and Heel Generated Force Waves. 9th International Congress on Applied Mechanics, Canada, 1983.
7 Stude DE, Brink DK. Effects of nine holes of simulated golf and orthotic intervention on balance and proprioception in experienced golfers. J Manip Physiol Ther 1997; 20:590-601.