Diagnosis and Chiropractic Management of Post-Traumatic Piriformis Syndrome: A Case Study
A 37-year-old male patient presented himself at a local chiropractic clinic with a chief complaint of persistent low back pain that was radiating into his left buttock, all along the posterolateral aspect of his left thigh and calf, and to the lateral aspect of the foot.
History of the patient illness
The pain initiated 2 years ago. The patient reported a blunt trauma of his left buttock in a motorcycle accident 8 months before his symptoms were first noticed. The patient was presented with low back pain, radiating from sacrum and gluteal region to the lateral aspect of the foot, all along the posterolateral aspect of his left thigh and calf. The pain was occasionally accompanied by paresthaesia and burning sensation. When asked to rate his pain with a numeric rating scale (NRS), he noted his low back pain to be 3/10 at best and 7/10 at worst.
Prolonged sitting and car driving aggravated his symptoms. And standing up and walking a few steps for a moment would make the pain partially relieved. The patient also noted that prolonged external rotation of the affected hip (sitting posture) made the symptoms more intense. He avoided sitting in a cross-leg posture due to the pain.
The patient had a transient relief of his pain after treatment of physiotherapy. However, the pain came back after a few days.
Other than the traumatic fall on his left hip in a motorcycle accident, the patient’s medical history was not remarkable.
Relative family history, social and environment history
Both of the patient’s parents were diagnosed with disc herniation of the lumbar spine in their 50s.
The patient went to gym 4 times per week, doing cardiovascular and weight bearing training. And he used to play soccer once a week. However he had to stop playing since his low back pain and leg pain started to bother him.
The patient was an attorney and his job required him to sit in front of his desk for more than 6 hours per day. He reported that he had to stand up and walk a few steps in the office every 30 minutes due to the pain.
The patient’s symptoms were partially relieved by taking Panadols. He was not taking any other prescribed or non-prescribed medications.
List of possible diagnoses from the patient history
Lumbar disc herniation
The patient was presented with symptoms and signs of radiculopathy including sensation disturbance of the lower limb, pain shooting to the foot, and pain worsened by sitting and relieved by walking. According to the dermatome, the nerve roots of L5, S1 or S2 were possibly affected.
Considering that both of the patient’s parents are diagnosed with lumbar disc herniation, it should be on top of the differential diagnosis list, for recent studies have suggested that lumbar disc herniation may be attributed more to genetic factors than to environmental and constitutional risk factors. The patient’s occupation which kept him sitting for a prolonged time increases the chance of lumbar disc herniation.
The history of blunt trauma could also be a factor of developing lumbar disc herniation.
Sciatic nerve irritation of other origins
The patient’s altered sensation on the lower extremity is in the distribution of sciatic nerve. Sciatica should be taken into consideration. However, the underlying cause of compression or irritation of sciatic nerve should be revealed with further examination and investigation.
Piriformis syndrome is an uncommon form of sciatica in which the sciatic nerve is compressed and irritated by piriformis muscle. It usually occurs in people who are middle-aged (mean age 38 years old).
Robinson described 5 significant manifestations of piriformis syndrome in 1947, including: (1) history of trauma in the gluteal region; (2) pain in the sciatic nerve distribution; (3) symptoms relieved by traction and aggravated by sitting or stooping; (4) palpable tenderness or mass over piriformis muscle; (5) positive straight leg raise test.
This patient was presented with the first 3 features of piriformis syndrome, whereas the 4th and 5th need further examination.
Sacroiliac joint syndrome
Sacroiliac joint syndrome is the dysfunction of sacroiliac joint that is attributed to either hypermobility or hypomobility, causing low back pain, buttock pain and sciatic lower limb pain. Lower abdomen, groin and medial thigh are occasionally affected as well. The symptoms of sacroiliac joint syndrome and sciatica are often similar.
Another possible differential diagnosis is hamstring syndrome. Hamstring syndrome is caused by entrapment of the proximal sciatic nerve by the hamstring tendons (1). It usually occurs associated with trauma such as hamstring tears or strain (2). However, in many cases, not significant history of trauma is noted (1, 2).
Patients with hamstring syndrome present with lower gluteal pain and radiate down to posterior thigh and knee (2). The symptoms are similar to sciatica of other origins.
Results of the neurological exams
Observation, static palpation and range of motion
Observation and static palpation are performed to look for any degree of antalgic posturing, any deviation from a normal spinal curve, pelvic position, and muscle spasm or bulks. Characteristic findings of each differential diagnosis are listed below.
Lumbar disc herniation
- Possible hyper-lordosis of lumbar spine in an antalgic posture;
- Significant decrease in lumbar active and passive range of motion, especially in lumbar flexion and unilateral lateral flexion;
- Possible limited hip range of active motion due to muscle weakness;
- Possible palpable restricted lumbar vertebral segments;
- Hypertonic or tender lumbar muscles on static palpation, especially erector spinae (ES) muscles;
- Possible limping or walking with the assistance with crutches due to pain and lower extremity muscle weakness;
- Possible hip external rotation on the affected side due to excessive piriformis muscle contraction, which is also known as “piriformis sign” (3);
- Significant decrease in hip active and passive range of motion, especially in hip internal rotation and adduction;
- Ipsilateral short leg (3);
- Tenderness at the sciatic notch on palpation;
- Possible hypertonic gluteal muscles (3);
Findings depend on the causes of sciatica such as lumbar disc herniation, piriformis syndrome and hamstring syndrome.
- The posterior superior iliac spines (PSIS) on both sides are not at the same horizontal level;
- Possible redness and swelling at the affected sacroiliac joint;
- Possible leg length discrepancy;
- Significant decrease in sacroiliac joint mobility;
- Possible local tenderness on static palpation;
- The pain is more localized, but possibly radiating;
- Tenderness of hamstring tendons or over ischial tuberosity on static in palpation;
- Significant decrease in hip active range of motion, especially in hip extension;
On observation, static palpation and range of motion assessment, the patient was noticed for:
- Positive piriformis sign (hip external rotation) on the ipsilateral (left) side;
- A relatively shorter left leg compared with the right leg;
- Tenderness over contralateral (right) sacroiliac joint;
- A palpable “sausage-shaped” mass in the ipsilateral (left) gluteal region (3);
- Hypertonic left hamstrings;
- Tenderness over left sciatic notch on static palpation;
- Limited hip active and passive range of motion, especially internal rotation;
- Decrease in sacroiliac joint mobility;
Other findings were not remarkable. The results of the assessment suggested that piriformis syndrome and sacroiliac syndrome were most possible diagnoses.
Coordination and gait analysis
Coordination and gait should be examined before other assessments are done, for this test provides us a big picture of the patient’s lower extremity function including motor function, joint integrity and coordination. Any gait dysfunction or antalgic gait should be recognized and further tests should be performed to look for the causes.
No abnormal movement or disturbance of the patient’s gait was observed. He also reported a partial relief of symptoms when he was walking. The insignificant findings made lumbar disc herniation less likely, however, there was still a possibility.
Sensory exams of peripheral nerves were performed to look for any sensation change on the symptomatic lower limb, which would lead to localization of the lesion. Assessments included fine touch, pain, temperature, and proprioception.
Decrease in two-point discrimination and light touch was noticed over the lateral aspect of the left leg and foot.
Lower extremity muscle strength was tested to identify which nerve roots were affected according to myotomes.
On examination, no significant findings were noticed.
deep tendon Reflex
Abnormal deep tendon reflex may be seen in lesions of muscles, sensory neurons, lower/upper motor neurons, neuromuscular junction and mechanical factors such as joint disease.
On examination, the patient’s Achilles reflexes were normal (+2) on both sides. An abnormal Achilles reflex suggests a tibial nerve lesion (S1-2).
Straight leg raise
The test is designed to look for any impingement of the dura and spinal cord or nerve roots of the lower lumbar spine, especially in sciatic nerve (L4, L5, S1).
The patient’s result was negative (70°), suggesting less possible lumbar disc herniation.
Bonnet’s test is a variant of straight leg raise and used to test for entrapment of sciatic nerve by piriformis muscle.
The patient’s result was positive, indicating possible piriformis syndrome.
Bowstring test is another variant of straight leg raise and used to test for entrapment of sciatic nerve by hamstrings.
The patient’s result was negative, suggesting less possible hamstring syndrome.
Valsalva maneuver was done to look for any disc herniation causing radiculopathy. This would increase intrathecal pressure which may reproduce the patient’s symptoms.
The patient’s result was negative, indicating less possible lumbar disc herniation.
Lumbar compression-distraction test
This test is also designed to look for disc herniation. When the compressive force is applied, it increases the intrathecal pressure and replicates symptoms if the patient has disc herniation. And the symptoms are relieved by distraction.
The patient’s result was negative, suggesting it was less likely to be disc herniation.
Gaenslen’s test is to assess sacroiliac joint involvement.
The patient’s result is negative.
Yeoman’s test is designed to assess the integrity of the sacroiliac joint.
The patient’s result is negative.
Squat test is designed for quick screening of lower limb pathologies including joint disease, motor and sensory neuron lesions.
The patient’s result was positive.
Supported belt test
Supported belt test helps to determine whether the pain is of lumbar origin or pelvic origin.
The patient was noticed for having pain only without supported belt, suggesting his symptoms were caused by pelvic dysfunction.
List of possible diagnoses from the neurological exam
- Piriformis syndrome
- Sacroiliac syndrome
Further blood and radiological tests
At this stage, no further imaging or other tests are needed, for the diagnosis can be made based on the patient’s history and results of neurological and orthopaedic examinations.
It is recommended that the patient should be treated for piriformis syndrome at the start. A conservative treatment plan should be designed to reduce pain intensity, stretch hypertonic muscles and increase lumbar and sacroiliac joint mobility.
However, if the patient does not respond to the treatment or the symptoms are worsened after the treatment, further investigations should be done. Considering a large extent of soft tissue and nerve involvement, magnetic resonance imaging (MRI) would be the most effective imaging method. A lumbopelvic view should be taken. This does not only demonstrate possible hypertrophied piriformis muscle and sciatic nerve entrapment, but also helps to rule out other differential diagnoses such as lumbar disc herniation. Nevertheless, many studies failed to show consistence of radiographic abnormalities in piriformis syndrome. Therefore, no significant findings on MRI do not necessarily exclude piriformis syndrome.
CT and ultrasound are also used to look for abnormality of piriformis muscle, but they are not as sensitive as MRI. EMG is an investigation to assess abnormal spontaneous activity of muscles which are innervated by sciatic nerve, thus differentiating sciatica and lumbosacral radiculopathy; however, EMG findings are often normal in piriformis syndrome.
Local injection of anaesthetics or steroid can be applied for both diagnostic and therapeutic purposes (4). This technique is widely used after initial evaluation. However, the specificity and efficacy is not well determined by clinical trials (4). A certain portion of patients with piriformis syndrome do not respond to piriformis muscle injection (5).
Based on the patient’s history, the results of neurologic and orthopaedic examinations, and likely radiographic findings, piriformis syndrome is the most likely diagnosis.
Conservative treatment is recommended at this stage, for 79% of patients with piriformis syndrome showed a significant improvement with use of non-steroid anti-inflammatory drugs (NSAIDs), muscle relaxants, thermo-therapy and rest (fishman, osteopathic approach). The aim of the chiropractic treatment is to reduce the intensity of pain, relax piriformis muscle, increase the range of motion of the hip joint, and increase mobility of lumbar and sacroiliac joint.
The tone and length of the left piriformis muscle and other affected muscles (hamstrings, other lateral rotators, gluteus muscles) should be assessed with chiropractic muscle test and static palpation. Any trigger point, tenderness, hypertonia are noted. Stretching exercise and muscle release are introduced first to help the patient relax the hypertonic piriformis muscle. The patient needs to receive the muscle release training daily for 2 weeks until the muscle tone is assessed again and any improvement of his symptoms is seen. Stretching of other affected hypertonic muscles is also required.
The mobility of the patient’s lumbar spine and sacroiliac joint should be assessed with orthopaedic examinations and chiropractic motion palpation. Any restricted segment is adjusted with high-velocity low-amplitude (HVLA) spinal manipulation. Chiropractic adjustments help to relieve pain, increase joint mobility and re-establish biomechanical stability of the body.
4.Jankovic D. Brief review: Piriformis syndrome: etiology, diagnosis, and management Article de synthèse court: Le syndrome du muscle piriforme – étiologie, diagnostic et prise en charge. Canadian journal of anesthesia. 2013 10;60(10):1003-12.
5.Martin HD, Martin H. Diagnostic accuracy of clinical tests for sciatic nerve entrapment in the gluteal region. Knee surgery, sports traumatology, arthroscopy : official journal of the ESSKA. 2014 04;22(4):882-8.
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