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Piriformis Syndrome

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Other Names

  • Piriformis Syndrome (PS)
  • Piriformis Muscle Pain
  • Piriformis Dysfunction
  • Deep Gluteal Syndrome
  • Posterior Gluteal Myofascial Pain Syndrome
  • Primary Piriformis Syndrome

Background

  • This page refers to piriformis syndrome
    • Sciatica has multiple causes and is discussed seperately
  • Controversy
    • Considered mildly controversial
    • Of 29 surveyed physiatrists, only 21 believed that condition exists[1]
    • Some authors argue that sciatica must be present to diagnose piriformis syndrome

History

  • First described in the literature in 1928[2]
  • First proposed as a cause of sciatic pain by Freiberg in 1934[3]

Epidemiology

  • Females to male ratio is about 6:1
  • Prevalence
    • Annual prevalence estimated to be between 2.2% and 19.5%[4]
    • Lifetime between 12% and 27%
  • Sciatica
    • Only about 6-8% of all cases of sciatica are due to piriformis syndrome[5]

Pathophysiology

  • Etiology
    • Trauma to piriformis muscle
    • Piriformis muscle hypertrophy often seen in athletes
    • Piriformis muscle spasm
    • Sitting for prolonged periods of time (officer workers, bicyclists, taxi or truck drivers)
    • Anatomic variants (see: Piriformis)
  • Sciatic pain
    • In approximately 15-20% of individuals, the sciatic nerve tracks through the body of the Piriformis muscle
    • However, only about about 6-8% of all cases of sciatica are due to piriformis syndrome[5]

Pathoanatomy

  • Piriformis
    • ~15% of individuals have abnormal relationship between piriformis muscle and Sciatic Nerve
    • Abnormal anatomy may not increase risk of developing piriformis syndrome[6]

Associated Pathology


Risk Factors

  • Generally, poorly understood
  • Anatomic risk
    • Only known when patient is imaged or undergoes surgery
  • Sports based on case reports

Differential Diagnosis


Clinical Features

  • History
    • Patients describe a aching pain in their buttocks
    • Pain may follow distribution of the sciatic nerve radiating down the posterior leg which is often shooting or burning
  • Physical Exam: Physical Exam Hip
    • Tenderness to deep palpation of the piriformis syndrome is identified in 92% of cases[10]
    • Patient may be tender to palpation of the greater sciatic notch[11]
    • There may be a a palpable, tender, sausage‐like mass or fibrous bands over the piriformis muscle
    • Although not routinely recommended, pain is reproducible with palpation of the piriformis during a rectal or vaginal exam[10]
  • Special Tests

Evaluation

Radiographs

MRI

  • Imaging modality of choice if there is diagnostic uncertainty
  • May need to image lumbar spine to clarify etiology
  • Consider MR neurography which suppresses signal from surrounding tissue
    • Can be helpful in unclear cases
    • In one study, 86% of patients had abnormal signal in the ipsilateral sciatic nerve[12]
    • In a second study of 239 patients in which diagnosis was uncertain, MR neurography identified edema of the ipsilateral sciatic nerve in 94% of patients[13]

CT

  • Alternative option if MRI unavailable

Ultrasound

  • Sonopalpation with dynamic ultrasound can be utilized for more accurate assessment of the painful muscle
    • Piriformis is relatively small, deep muscle can be hard to palpate
    • May identify other causes of pain including gluteal muscles, external rotators[14]
  • May be helpful to assess the sciatic nerve cross-sectional area, but more research is needed

EMG/NCS

  • Often normal, may be used to exclude other conditions or causes of radiculopathy
  • Fishman et al found a delay in the H reflex on EMG in the FAIR position (described below) in patients with PS compared to asymptomatic controls[15]

Classification

Clinical Scoring System

Classification Point
Unilateral or bilateral buttock pain with fluctuating periods of pain through the day 1
No lower back pain 1
No pain upon palpation of axial spine 1
Negative result for Straight Leg Raise 1
Prolonged sitting triggers gluteal pain or sciatica 1
Fluctuating sciatica through the course of the day 1
Positive FAIR or Freiberg sign 1
Positive Beatty sign 1
Positive Palpation 1
Sciatica reproduced by Fair or Freiberg test 1
Sciatica reproduced by Beatty test 1
Absence of perineal irradiation 1
  • Proposed by Michael et al[16]
    • Score of 8 or greater is probably PS
    • Score of 7-8 makes diagnosis unlikely
    • Score under 6 should consider another diagnosis

Management

Prognosis

  • In 250 patients treated with medications (NSAIDS, muscle relaxant) and physical therapy, 51.2% had resolution of symptoms[16]
  • Fishmnan et al[15]
    • Use of physical therapy combined with corticosteroid injection
    • led to at least 50% relief in 79% of their 665 patients
  • In patients treated surgically, there are small cohorts with positive results
    • Most (59-69%) report good-to-excellent results[17]

Nonoperative

  • Medications
  • Physical Therapy
    • Piriformis muscle often has increased resting tone
    • Important to target trigger points, tight bands and attempt to restore normal muscle tone[18]
    • Any protocol should include stretching exercises for the piriformis and gluteal muscle groups
    • Also focus on lumbosacral stability, hip strengthening
    • Correction of biomechanical errors across the hip, pelvis, and spine
    • In patients with sciatica, individuals should work on nerve glide or neuroglide techniques
  • Manual Therapy
    • Consider dry needling, acupuncture, manual overpressure, and massage

Corticosteroid Injection

  • General
    • Can be diagnostic and therapeutic
    • Ultrasound guidance is up to 95% accurate, fluoroscopy or landmark based approach is only 30%[19]
  • Filler et al performed 162 MRI guided piriformis muscle injections[13]
    • 15% had complete relief (no recurrence), 8% had 2-4 months of relief with lasting relief after a repeat injection
    • 37% had 2-4 months of relief with a subsequent recurrence, 24% had less than 2 weeks of relief with subsequent recurrence, and 16% had no relief
  • Misirlioglu et al injected 57 patients with either lidocaine or lidocaine plus betamethasone under US guidance[20]
    • Both groupes experienced significant reduction in pain but there was no difference between the groups

Botulinum Toxin Injection

  • Can be considered in recalcitrant cases
  • Note that the medication is expensive
  • Fishman et al double blinded RCT[21]
    • Botulinum toxin superior to lidocaine plus steroids
  • Fishman et al in a second study[22]
    • Botulinum toxin injection into the piriformis muscle combined with physical therapy provided greater than 50% relief in 24 of 27 patients
    • led to a decrease in the mean Visual Analog Scale from 6.7 to 2.3

Operative

  • Indication
    • Failure of conservative measures
  • Technique
    • Tenotomy of piriformis muscle tendon and decompression of sciatic nerve

Rehab and Return to Play

Rehabilitation

  • Needs to be updated

Return to Play

  • Needs to be updated

Complications

  • Chronic pain
  • Disability
  • Inability to return to sport
  • Surgical complications include
    • Damage to sciatic nerve
    • Infection
    • Bleeding

See Also


References

  1. Silver JK, Leadbetter WB (1998) Piriformis syndrome: assessment of current practice and literature review. Orthopedics 21:1133–1135
  2. Y W. The relation of arthritis of the sacroiliac joint to sciatica. Lancet. 1928;2:1119‐1122.
  3. Freiberg AH, Vinke TH (1934) Sciatica and the sacro-iliac joint. J Bone Joint Surg Am 16:126–136
  4. Konstantinou K, Dunn KM. Sciatica: review of epidemiological studies and prevalence estimates. Spine. 2008;33(22):2464‐2472.
  5. 5.0 5.1 Hallin RP. Sciatic pain and the piriformis muscle. Postgrad Med. 1983;74(2):69‐72.
  6. Bartret AL, Beaulieu CF, Lutz AM. Is it painful to be different? Sciatic nerve anatomical variants on MRI and their relationship to piriformis syndrome. Eur Radiol. 2018;28(11):4681‐4686.
  7. Zeren, B., et al. "Bilateral piriformis syndrome in two elite soccer players: Report of two cases." Orthopaedics & Traumatology: Surgery & Research 101.8 (2015): 987-990.
  8. Mayrand N, Fortin J, Descarreaux M, et al. Diagnosis and management of posttraumatic piriformis syndrome: a case study. J. Manipulative Physiol. Ther. 2006; 29:486Y491.
  9. Julsrud ME. Piriformis syndrome. J. Am. Podiatr. Med. Assoc. 1989; 79: 128Y131.
  10. 10.0 10.1 Durrani Z, Winnie AP. Piriformis muscle syndrome: an underdiagnosed cause of sciatica. J Pain Symptom Manage. 1991;6(6):374‐379.
  11. Hopayian K, Song F, Riera R, Sambandan S. The clinical features of the piriformis syndrome: a systematic review. Eur Spine J. 2010;19(12):2095‐2109.
  12. Lewis AM, Layzer R, Engstrom JW, Barbaro NM, Chin CT. Magnetic resonance neurography in extraspinal sciatica. Arch Neurol. 2006; 63(10):1469-1472.
  13. 13.0 13.1 Filler AG, Haynes J, Jordan SE, et al. Sciatica of nondisc origin and piriformis syndrome: diagnosis by magnetic resonance neurography and interventional magnetic resonance imaging with outcome study of resulting treatment. J Neurosurg Spine. 2005;2(2):99-115.
  14. Battaglia PJ, Mattox R, Haun DW, Welk AB, Kettner NW. Dynamic ultrasonography of the deep external rotator musculature of the hip: a descriptive study. PM R. 2016;8(7):640‐650.
  15. 15.0 15.1 . Fishman LM, Dombi GW, Michaelsen C et al (2002) Piriformis syndrome: diagnosis, treatment, and outcome—a 10-year study. Arch Phys Med Rehabil 83:295–301
  16. 16.0 16.1 Michel F, Decavel P, Toussirot E, et al. Piriformis muscle syndrome: diagnostic criteria and treatment of a monocentric series of 250 patients. Ann Phys Rehabil Med. 2013;56(5):371-383.
  17. Byrd JW. Piriformis syndrome. Oper. Tech. Sports Med. 2005; 13:71Y79
  18. Papadopoulos EC, Khan SN. Piriformis syndrome and low back pain: a new classification and review of the literature. Orthop Clin North Am. 2004;35(1):65-71.
  19. Finnoff JT, Hurdle MF, Smith J. Accuracy of ultrasound-guided versus fluoroscopically guided contrast-controlled piriformis injections: a cadaveric study. J Ultrasound Med. 2008;27(8):1157-1163.
  20. Misirlioglu TO, Akgun K, Palamar D, Erden MG, Erbilir T. Piriformis syndrome: comparison of the effectiveness of local anesthetic and corticosteroid injections: a double-blinded, randomized controlled study. Pain Physician. 2015;18(2):163-171.
  21. Fishman LM, Anderson C, Rosner B. BOTOX and physical therapy in the treatment of piriformis syndrome. Am J Phys Med Rehabil. 2002;81(12):936-942.
  22. Fishman LM, Konnoth C, Rozner B. Botulinum neurotoxin type B and physical therapy in the treatment of piriformis syndrome: a dosefinding study. Am J Phys Med Rehabil. 2004;83(1):42-50. quiz 51-43.
Created by:
John Kiel on 5 July 2019 08:43:51
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Last edited:
5 October 2022 13:06:59
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