Piriformis Syndrome

Piriformis Syndrome

No Results

No Results


Low back pain (LBP), is ubiquitous. An estimated 30-45% of persons aged 18-55 years have some form of back pain in their lifetime. LBP most commonly involves one of the following conditions: sciatic nerve entrapment, herniated nucleus pulposus, direct trauma, muscle spasm due to chronic or overuse injury, or piriformis syndrome.

Piriformis syndrome (see the image below) is characterized by pain and instability. The location of the pain is often imprecise, but it is often present in the hip, coccyx, buttock, groin, or distal part of the leg. The history and physical findings are key elements in differentiating the more common forms of LBP and piriformis syndrome. The literature and general knowledge on piriformis syndrome is limited, compared with that of sciatica or disc herniation. However, the common findings associated with piriformis syndrome are agreed upon.

Yeoman first described piriformis syndrome in 1928 as periarthritis of the anterior sacroiliac joint. The history of this condition stems from one of many causes of lower back and leg pain. Many patients who underwent unsuccessful surgery in the lumbosacral region were later found to have piriformis syndrome.

For patient education resources, see the Osteoporosis and Bone Health Center and Back, Ribs, Neck, and Head Center, as well as Back Pain.

United States

The female-to-male incidence ratio of piriformis syndrome is 6:1. In one study at a regional hospital, 45 of 750 patients with LBP were found to have piriformis syndrome. Another author estimated that the incidence of piriformis syndrome in patients with sciatica is 6%.

The function of the piriformis muscle is to externally rotate and abduct the thigh. The sacral plexus is closely associated with the anterior surface of the piriformis muscle. The lumbosacral trunk and the ventral rami of the first 3 sacral nerves form the sacral plexus. The sciatic nerve passes inferior to the piriformis muscle.

The sciatic nerve exits the pelvis via 4 routes: (1) The nerve passes anteriorly to the piriformis between the rims of the greater sciatic foramen. (2) The peroneal portion of the sciatic nerve passes through the piriformis; the tibial portion passes anterior to the piriformis muscle. (3) The peroneal branch of the sciatic nerve loops above and posterior to the piriformis muscle, whereas the tibial branch passes anterior to the piriformis muscle. (4) The undivided sciatic nerve penetrates the piriformis muscle.

Dysfunction of the piriformis muscle can cause signs and symptoms of pain in the sciatic nerve distribution, that is, in the gluteal area, posterior thigh, posterior leg, and lateral aspect of the foot. [1]

Gait mechanics help in demonstrating the physiologic features of piriformis hypertrophy. When a person takes a step forward, the extremity moves from external rotation to internal rotation, and the piriformis muscle lengthens. This stretching is followed by reflex contraction. A second contraction in the initially stretched piriformis muscle occurs when the opposite foot swings forward. This gait pattern leads to hypertrophy, and the dual contraction is further exacerbated by the stretching of the piriformis muscle on the side of a shortened leg.

More commonly, piriformis syndrome is secondary to inflammation due to gluteal trauma or spasm. The effect of this inflammatory process on the sciatic nerve is chemical rather than mechanical. Several theories suggest that the following are key factors in the muscle hyperfunction or spasm that leads to an interstitial myofibrositis: extravasation of blood; release of serotonin from platelets; and prostaglandin E, serotonin, bradykinin, and histamine release.

Although no general consensus about the etiology and pathophysiology of piriformis syndrome exists, many physicians and physical therapists attribute this syndrome to a specific mechanism involving the sciatic nerve. For example, Benson and Schutzer attributed the syndrome to blunt trauma to the buttocks that results in hematoma formation and subsequent scarring between the sciatic nerve and the short external rotators. [2] Entrapment of the sciatic nerve at the sciatic trunk (where it leaves the pelvis and crosses the greater sciatic notch) is an infrequent cause. This entrapment can also occur as a result of an enlarged hypertrophic piriformis, an inflamed piriformis muscle, tumors, cysts, and pseudoaneurysms.

Jawish RM, Assoum HA, Khamis CF. Anatomical, clinical and electrical observations in piriformis syndrome. J Orthop Surg Res. 2010 Jan 21. 5:3. [Medline]. [Full Text].

Benson ER, Schutzer SF. Posttraumatic piriformis syndrome: diagnosis and results of operative treatment. J Bone Joint Surg Am. 1999 Jul. 81(7):941-9. [Medline].

Beatty RA. The piriformis muscle syndrome: a simple diagnostic maneuver. Neurosurgery. 1994 Mar. 34(3):512-4; discussion 514. [Medline].

Robinson ES, Lindley EM, Gonzalez P, Estes S, Cooley R, Burger EL, et al. Piriformis syndrome versus radiculopathy following lumbar artificial disc replacement. Spine (Phila Pa 1976). 2011 Feb 15. 36(4):E282-7. [Medline].

Boyajian-O’Neill LA, McClain RL, Coleman MK, Thomas PP. Diagnosis and management of piriformis syndrome: an osteopathic approach. J Am Osteopath Assoc. 2008 Nov. 108(11):657-64. [Medline]. [Full Text].

Fowler IM, Tucker AA, Weimerskirch BP, Moran TJ, Mendez RJ. A randomized comparison of the efficacy of 2 techniques for piriformis muscle injection: ultrasound-guided versus nerve stimulator with fluoroscopic guidance. Reg Anesth Pain Med. 2014 Mar-Apr. 39(2):126-32. [Medline].

Blunk JA, Nowotny M, Scharf J, Benrath J. MRI verification of ultrasound-guided infiltrations of local anesthetics into the piriformis muscle. Pain Med. 2013 Oct. 14(10):1593-9. [Medline].

Ozisik PA, Toru M, Denk CC, Taskiran OO, Gundogmus B. CT-guided piriformis muscle injection for the treatment of piriformis syndrome. Turk Neurosurg. 2014. 24(4):471-7. [Medline].

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 Mar-Apr. 18 (2):163-71. [Medline].

Fishman LM, Wilkins AN, Rosner B. Electrophysiologically Identified Piriformis Syndrome is successfully treated with Incobotulinum toxin A and Physical Therapy. Muscle Nerve. 2016 Dec 9. [Medline].

Naja Z, Al-Tannir M, El-Rajab M, et al. The effectiveness of clonidine-bupivacaine repeated nerve stimulator-guided injection in piriformis syndrome. Clin J Pain. 2009 Mar-Apr. 25(3):199-205. [Medline].

Filler AG. Piriformis and related entrapment syndromes: diagnosis & management. Neurosurg Clin N Am. 2008 Oct. 19(4):609-22, vii. [Medline].

Greenman PE. Piriformis syndrome. Principles in Manual Medicine. 2nd ed. Baltimore, Md: Lippincott Williams & Wilkins; 1996. 467-74.

Jankiewicz JJ, Hennrikus WL, Houkom JA. The appearance of the piriformis muscle syndrome in computed tomography and magnetic resonance imaging. A case report and review of the literature. Clin Orthop Relat Res. 1991 Jan. 262:205-9. [Medline].

Julsrud ME. Piriformis syndrome. J Am Podiatr Med Assoc. 1989 Mar. 79(3):128-31. [Medline].

Medical Economics. Physicians’ Desk Reference. Montvale, NJ: Thompson Medical Economics; 1999.

Merlo IM, Poloni TE, Alfonsi E, Messina AL, Ceroni M. Sciatic pain in a young sportsman. Lancet. 1997 Mar 22. 349(9055):846. [Medline].

Naja Z, Al-Tannir M, El-Rajab M, et al. The effectiveness of clonidine-bupivacaine repeated nerve stimulator-guided injection in piriformis syndrome. Clin J Pain. 2009 Mar-Apr. 25(3):199-205. [Medline].

Ozaki S, Hamabe T, Muro T. Piriformis syndrome resulting from an anomalous relationship between the sciatic nerve and piriformis muscle. Orthopedics. 1999 Aug. 22(8):771-2. [Medline].

Pace JB, Nagle D. Piriformis syndrome. West J Med. 1976. 24:435-9.

Papadopoulos SM, McGillicuddy JE, Albers JW. Unusual cause of ‘piriformis muscle syndrome’. Arch Neurol. 1990 Oct. 47(10):1144-6. [Medline].

Parziale JR, Hudgins TH, Fishman LM. The piriformis syndrome. Am J Orthop. 1996 Dec. 25(12):819-23. [Medline].

Pecina HI, Boric I, Smoljanovic T, Duvancic D, Pecina M. Surgical evaluation of magnetic resonance imaging findings in piriformis muscle syndrome. Skeletal Radiol. 2008 Nov. 37(11):1019-23. [Medline].

Silver JK, Leadbetter WB. Piriformis syndrome: assessment of current practice and literature review. Orthopedics. 1998 Oct. 21(10):1133-5. [Medline].

Steiner C, Staubs C, Ganon M, Buhlinger C. Piriformis syndrome: pathogenesis, diagnosis, and treatment. J Am Osteopath Assoc. 1987 Apr. 87(4):318-23. [Medline].

Tibor LM, Sekiya JK. Differential diagnosis of pain around the hip joint. Arthroscopy. 2008 Dec. 24(12):1407-21. [Medline].

Hopayian K, Danielyan A. Four symptoms define the piriformis syndrome: an updated systematic review of its clinical features. Eur J Orthop Surg Traumatol. 2018 Feb. 28 (2):155-164. [Medline].

Najdi H, Mouarbes D, Abi-Akl J, Karnib S, Chamsedine AH, Jawish R. EMG in piriformis syndrome diagnosis: Reliability of peroneal H-reflex according to results obtained after surgery, Botox injection and medical treatment. J Clin Neurosci. 2018 Nov 27. [Medline].

Shishir Shah, DO Consulting Staff, Comprehensive Woundcare, Banner Baywood Hospital

Shishir Shah, DO is a member of the following medical societies: American Academy of Family Physicians, American Medical Association, American Osteopathic Association

Disclosure: Nothing to disclose.

Thomas W Wang, MD Consulting Staff, Department of Occupational Medicine, Kaiser-Permanente

Thomas W Wang, MD is a member of the following medical societies: American Academy of Family Physicians

Disclosure: Nothing to disclose.

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Received salary from Medscape for employment. for: Medscape.

Russell D White, MD Clinical Professor of Medicine, Clinical Professor of Orthopedic Surgery, Department of Community and Family Medicine, University of Missouri-Kansas City School of Medicine, Truman Medical Center-Lakewood

Russell D White, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Family Physicians, American Association of Clinical Endocrinologists, American College of Sports Medicine, American Diabetes Association, American Medical Society for Sports Medicine

Disclosure: Nothing to disclose.

Sherwin SW Ho, MD Associate Professor, Department of Surgery, Section of Orthopedic Surgery and Rehabilitation Medicine, University of Chicago Division of the Biological Sciences, The Pritzker School of Medicine

Sherwin SW Ho, MD is a member of the following medical societies: American Academy of Orthopaedic Surgeons, Arthroscopy Association of North America, Herodicus Society, American Orthopaedic Society for Sports Medicine

Disclosure: Received consulting fee from Biomet, Inc. for speaking and teaching; Received grant/research funds from Smith and Nephew for fellowship funding; Received grant/research funds from DJ Ortho for course funding; Received grant/research funds from Athletico Physical Therapy for course, research funding; Received royalty from Biomet, Inc. for consulting.

Joseph P Garry, MD, FACSM, FAAFP Associate Professor, Department of Family Medicine and Community Health, University of Minnesota Medical School

Joseph P Garry, MD, FACSM, FAAFP is a member of the following medical societies: American Academy of Family Physicians, American Medical Society for Sports Medicine, Minnesota Medical Association, American College of Sports Medicine

Disclosure: Nothing to disclose.

Piriformis Syndrome

Research & References of Piriformis Syndrome|A&C Accounting And Tax Services