Piriformis syndrome is a rare neuromuscular condition, caused as a result of entrapment or compression of the sciatic nerve by the piriformis muscle, commonly at the infra-piriformis canal. The most common symptom of this condition includes sciatica which intensifies with certain triggering positions.
The anatomy of the piriformis muscle, as described by Dr. Samarjit Dey, originates from the anterior surface of the S2-S4 sacral vertebrae, the capsule of the sacroiliac joint, and the gluteal surface of the ileum near the posterior surface of the iliac spine.
It is innervated by the branches of L5, S1 and S2 spinal nerves. The sciatic nerve, posterior femoral cutaneous nerve, gluteal nerves, and the gluteal vessels pass below the piriformis muscle.
There are two types of Piriformis syndrome – primary and secondary. The former involves anatomical causes that may include a split piriformis muscle, split sciatic nerve or an anomalous sciatic nerve path.
Secondary Piriformis syndrome is typically the result of a precipitating cause that includes macrotrauma, microtrauma, ischemic mass effect and local ischemia. Trauma is often identified as the triggering factor which can occur several months before the onset of initial symptoms of the condition.
As outlined by Mitra et al., the clinical presentation of the condition involves intense pain that can radiate from the sacrum through the gluteal area and down the posterior aspect of the thigh, usually stopping above the knee.
This is typically over the piriformis muscle attachments or lower part of the back, with the pain improving during ambulation, only to worsen with no movement.
It is important to note that in order to successfully diagnose Piriformis syndrome, a full history and physical assessment of the patient is essential. This is because this condition can mimic other conditions and can include all other causes of lower back pain and sciatic.
This can include, but may not be limited to, spinal stenosis, facet syndrome, sacroiliac joint dysfunction, trochanteric bursitis, pelvic tumor, endometriosis and various conditions that irritate the sciatic nerve.
The authors describe the following physical examination signs to help confirm the presence of Piriformis syndrome – pace sign or pain and weakness on resisted abduction of the hip while the patient is seated; laseque sign or pain on voluntary flexion, adduction, and internal rotation of the hip; Freiberg sign or pain on forced internal rotation of the extended thigh.
Conservative measures can be implemented in the initial stages of the condition. This may include a combination of rest, cryotherapy, muscle relaxants and anti-inflammatory medications.
Strengthening of the abductor and adductor muscles in addition to stretching of the piriformis muscle can also help in a treatment programme for Piriformis syndrome.
An effective exercise programme should be designed for patients with the condition so as to improve range of motion of the surrounding muscle groups and joints, as well as to increase strength in the targeted muscle groups, including the piriformis muscle.
The inclusion of MASS4D® custom orthotics in a rehabilitative programme is recommended in order to minimise any foot postural disparities such as pes planus or pes cavus that can further elevate stress on the affected muscle groups.
The supportive properties of MASS4D® makes it an ideal ambulatory assistive device that can facilitate optimal re-alignment of muscles, tendons and ligaments of the body, while regulating dysfunctions in the overall kinetic chain.
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