European Spine Journal

, Volume 19, Issue 12, pp 2095–2109 | Cite as

The clinical features of the piriformis syndrome: a systematic review

  • Kevork Hopayian
  • Fujian Song
  • Ricardo Riera
  • Sidha Sambandan
Review Article


Piriformis syndrome, sciatica caused by compression of the sciatic nerve by the piriformis muscle, has been described for over 70 years; yet, it remains controversial. The literature consists mainly of case series and narrative reviews. The objectives of the study were: first, to make the best use of existing evidence to estimate the frequencies of clinical features in patients reported to have PS; second, to identify future research questions. A systematic review was conducted of any study type that reported extractable data relevant to diagnosis. The search included all studies up to 1 March 2008 in four databases: AMED, CINAHL, Embase and Medline. Screening, data extraction and analysis were all performed independently by two reviewers. A total of 55 studies were included: 51 individual and 3 aggregated data studies, and 1 combined study. The most common features found were: buttock pain, external tenderness over the greater sciatic notch, aggravation of the pain through sitting and augmentation of the pain with manoeuvres that increase piriformis muscle tension. Future research could start with comparing the frequencies of these features in sciatica patients with and without disc herniation or spinal stenosis.


Piriformis Sciatica Diagnosis Systematic review 



We thank Mrs Wendy Marsh, Head of Knowledge Services, Ipswich PCT for assistance with retrieval, and Prof. Milos Jenicek and Prof. Paul Glasziou for comments on the assessment of case studies. The study was partly funded by a grant from the Scientific Foundation Board of the Royal College of General Practitioners. The authors are independent of the funding body.

Conflicts of interest statement



  1. 1.
    Adams JA (1980) The pyriformis syndrome—report of four cases and review of the literature. S Afr J Surg 18:13–18PubMedGoogle Scholar
  2. 2.
    Banerjee T, Hall CD (1976) Sciatic entrapment neuropathy. Case report. J Neurosurg 45:216–217PubMedCrossRefGoogle Scholar
  3. 3.
    Barton PM (1991) Piriformis syndrome: a rational approach to management. Pain 47:345–352PubMedCrossRefGoogle Scholar
  4. 4.
    Beatty RA (1994) The piriformis muscle syndrome: a simple diagnostic maneuver. Neurosurgery 34:512–513PubMedCrossRefGoogle Scholar
  5. 5.
    Beauchesne RP, Schutzer SF (1997) Myositis ossificans of the piriformis muscle: an unusual cause of piriformis syndrome. A case report. J Bone Joint Surg 79:906–910PubMedGoogle Scholar
  6. 6.
    Benson ER, Schutzer SF (1999) Posttraumatic piriformis syndrome: diagnosis and results of operative treatment. J Bone Joint Surg Am 81:941–949PubMedCrossRefGoogle Scholar
  7. 7.
    Benzon HT, Katz JA, Benzon HA, Iqbal MS (2003) Piriformis syndrome: anatomic considerations, a new injection technique, and a review of the literature. Anesthesiology 98:1442–1448PubMedCrossRefGoogle Scholar
  8. 8.
    Bernard TN, Kirkaldy-Willis WH (1987) Recognizing specific characteristics of nonspecific low back pain. Clin Orthop 217:266–280PubMedGoogle Scholar
  9. 9.
    Bossuyt PM, Reitsma JB, Bruns DE et al (2003) Towards complete and accurate reporting of studies of diagnostic accuracy: the STARD initiative. BMJ 326:41–44PubMedCrossRefGoogle Scholar
  10. 10.
    Broadhurst NA, Simmons DN, Bond MJ (2004) Piriformis syndrome: correlation of muscle morphology with symptoms and signs. Arch Phys Med Rehabil 85:2036–2039PubMedCrossRefGoogle Scholar
  11. 11.
    Brown JA, Braun MA, Namey TC (1988) Pyriformis syndrome in a 10-year-old boy as a complication of operation with the patient in the sitting position. Neurosurgery 23:117–119PubMedCrossRefGoogle Scholar
  12. 12.
    Bustamante S, Houlton PG (2001) Swelling of the leg, deep venous thrombosis and the piriformis syndrome. Pain Res Manag 6:200–203PubMedGoogle Scholar
  13. 13.
    Byrd JWT (2005) Piriformis syndrome. Oper Tech Sports Med 13:71–79CrossRefGoogle Scholar
  14. 14.
    Carey TS, Boden SD (2003) A critical guide to case series reports. Spine 28:1631–1634PubMedCrossRefGoogle Scholar
  15. 15.
    Centre for Evidence-based Medicine (2009) Oxford Centre for evidence-based medicine—levels of evidence. Accessed 7 July 2009
  16. 16.
    Centre for Reviews and Dissemination (2009) Systematic reviews. CRD’s guidance for undertaking reviews in health care. Accessed 7 July 2009
  17. 17.
    Chang CW, Shieh SF, Li CM, Wu WT, Chang KF (2006) Measurement of motor nerve conduction velocity of the sciatic nerve in patients with piriformis syndrome: a magnetic stimulation study. Arch Phys Med Rehabil 87:1371–1375PubMedCrossRefGoogle Scholar
  18. 18.
    Chantraine A, Gauthier C (1990) The pyriformis syndrome. Ann Readapt Med Phys 33:347–353Google Scholar
  19. 19.
    Chen WS (1992) Sciatica due to piriformis pyomyositis. Report of a case. J Bone Joint Surg Am 74:1546–1548PubMedGoogle Scholar
  20. 20.
    Chen WS (1994) Bipartite piriformis muscle: an unusual cause of sciatic nerve entrapment. Pain 58:269–272PubMedCrossRefGoogle Scholar
  21. 21.
    Chen WS, Wan YL (1992) Sciatica caused by piriformis muscle syndrome: report of two cases. J Formos Med Assoc 91:647–650PubMedGoogle Scholar
  22. 22.
    Chong KW, Tay BK (2004) Piriformis pyomyositis: a rare cause of sciatica. Singap Med J 45:229–231Google Scholar
  23. 23.
    Collier FC (1985) Acute monetary sciatica. Lancet 1079Google Scholar
  24. 24.
    Colmegna I, Justiniano M, Espinoza LR, Gimenez CR (2007) Piriformis pyomyositis with sciatica: an unrecognized complication of “unsafe” abortions. J Clin Rheumatol 13:87–88PubMedCrossRefGoogle Scholar
  25. 25.
    Cook MW, Levin LA, Joseph MP, Pinczower EF (1996) Traumatic optic neuropathy. A meta-analysis. Arch Otolaryngol Head Neck Surg 122:389–392PubMedGoogle Scholar
  26. 26.
    Cramp F, Bottrell O, Campbell H et al (2007) Non-surgical management of piriformis syndrome: a systematic review. Phys Ther Rev 12:66–72CrossRefGoogle Scholar
  27. 27.
    Dalmau-Carola J (2005) Myofascial pain syndrome affecting the piriformis and the obturator internus muscle. Pain Pract 5:361–363PubMedCrossRefGoogle Scholar
  28. 28.
    Dhote R, Tudoret L, Bachmeyer C, Legmann P, Christoforov B (1996) Cyclic sciatica. A manifestation of compression of the sciatic nerve by endometriosis. A case report. Spine 21:2277–2279PubMedCrossRefGoogle Scholar
  29. 29.
    Dionne CE, Dunn KM, Croft PR et al (2008) A consensus approach toward the standardization of back pain definitions for use in prevalence studies. Spine 33:95–103PubMedCrossRefGoogle Scholar
  30. 30.
    Durrani Z, Winnie AP (1991) Piriformis muscle syndrome: an underdiagnosed cause of sciatica. J Pain Symptom Manage 6:374–379PubMedCrossRefGoogle Scholar
  31. 31.
    El Rubaidi OA, Horcajadas AA, RodrÌguez RD, Galicia Bulnes JM (2003) Sciatic nerve compression as a complication of the sitting position. Neurocirugia 14:426–430PubMedGoogle Scholar
  32. 32.
    Ernst E (2002) Manipulation of the cervical spine: a systematic review of case reports of serious adverse events, 1995–2001. Med J Aust 176:376–380PubMedGoogle Scholar
  33. 33.
    Ernst E (2003) The safety of massage therapy. Rheumatology 42:1101–1106PubMedCrossRefGoogle Scholar
  34. 34.
    Ernst E (2005) Ophthalmological adverse effects of (chiropractic) upper spinal manipulation: evidence from recent case reports. Acta Ophthalmol Scand 83:581–585PubMedCrossRefGoogle Scholar
  35. 35.
    Ernst E (2007) Adverse effects of spinal manipulation: a systematic review. J R Soc Med 100:330–338PubMedCrossRefGoogle Scholar
  36. 36.
    Filler AG, Haynes J, Jordan SE et al (2005) 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 2:99–115PubMedCrossRefGoogle Scholar
  37. 37.
    Fishman LM, Dombi GW, Michaelsen C et al (2002) Piriformis syndrome: diagnosis, treatment, and outcome—a 10-year study. Arch Phys Med Rehabil 83:295–301PubMedCrossRefGoogle Scholar
  38. 38.
    Fishman LM, Zybert PA (1992) Electrophysiologic evidence of piriformis syndrome. Arch Phys Med Rehabil 73:359–364PubMedCrossRefGoogle Scholar
  39. 39.
    Fishman LM, Schaefer MP (2003) Piriforms syndrome: the piriformis syndrome is underdiagnosed. Muscle Nerve 28:646–649PubMedCrossRefGoogle Scholar
  40. 40.
    Foster MR (1999) Clinical trials for piriformis syndrome. Orthopedics 22:561–569PubMedGoogle Scholar
  41. 41.
    Foster MR (2002) Piriformis syndrome. Orthopedics 25:821–825PubMedGoogle Scholar
  42. 42.
    Freiberg AH, Vinke TH (1934) Sciatica and the sacro-iliac joint. J Bone Joint Surg Am 16:126–136Google Scholar
  43. 43.
    Freiberg AH (1937) Sciatic pain and its relief by operations on muscle and fascia. Arch Surg 34:337–350Google Scholar
  44. 44.
    Gandhavadi B (1990) Bilateral piriformis syndrome associated with dystonia musculorum deformans. Orthopedics 13:350–351PubMedGoogle Scholar
  45. 45.
    Guyomarc’h HF, Labanere C (2004) Piriformis muscle syndrome: differential diagnosis with sciatalgia in the athlete: three cases and a review of the literature. J Traumatol Surg 21:133–145CrossRefGoogle Scholar
  46. 46.
    Hallin RP (1983) Sciatic pain and the piriformis muscle. Postgrad Med 74:69–72PubMedGoogle Scholar
  47. 47.
    Hanania M, Kitain E (1998) Perisciatic injection of steroid for the treatment of sciatica due to piriformis syndrome. Reg Anesth Pain Med 23:223–228PubMedCrossRefGoogle Scholar
  48. 48.
    Hopayian K (1999) Sciatica in the community—not always disc herniation. Int J Clin Pract 53:197–198PubMedGoogle Scholar
  49. 49.
    Hughes SS, Goldstein MN, Hicks DG, Pellegrini VDJ (1992) Extrapelvic compression of the sciatic nerve. An unusual cause of pain about the hip: report of five cases. J Bone Joint Surg Am 74:1553–1559PubMedGoogle Scholar
  50. 50.
    Hulbert A, Deyle GD (2009) Differential diagnosis and conservative treatment for piriformis syndrome: a review of the literature. Curr Orthop Pract 20:313–319CrossRefGoogle Scholar
  51. 51.
    Indrekvam K, Sudmann E (2002) Piriformis muscle syndrome in 19 patients treated by tenotomy—a 1- to 16-year follow-up study. Int Orthop 26:101–103PubMedCrossRefGoogle Scholar
  52. 52.
    Jabs DA (2005) Improving the reporting of clinical case series. Am J Ophthalmol 139:900–905PubMedCrossRefGoogle Scholar
  53. 53.
    Jankiewicz JJ, Hennrikus WL, Houkom JA (1991) 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 262:205–209PubMedGoogle Scholar
  54. 54.
    Jenicek M (1999) Clinical case reporting in evidence-based medicine. Butterworth-Heinemann, OxfordGoogle Scholar
  55. 55.
    Jroundi L, El Quessar A, Chakir N, El Hassani MR, Jiddane M (2003) The piriformis syndrome: a rare cause of non discogenic sciatica. A case report. J Radiol 84:715–717PubMedGoogle Scholar
  56. 56.
    Julsrud ME (1989) Piriformis syndrome. J Am Podiatr Med Assoc 79:128–131PubMedGoogle Scholar
  57. 57.
    Karl RD Jr, Yedinak MA, Hartshorne MF et al (1985) Scintigraphic appearance of the piriformis muscle syndrome. Clin Nucl Med 10:361–363PubMedCrossRefGoogle Scholar
  58. 58.
    Karppinen J, Malmivaara A, Tervonen O et al (2001) Severity of symptoms and signs in relation to magnetic resonance imaging findings among sciatic patients. Spine 26:E149–E154PubMedCrossRefGoogle Scholar
  59. 59.
    Kent DL, Haynor DR, Longstreth WTJ, Larson EB (1994) The clinical efficacy of magnetic resonance imaging in neuroimaging. Ann Intern Med 120:856–871PubMedGoogle Scholar
  60. 60.
    Kirschner JS, Foye PM, Cole JL (2009) Piriformis syndrome, diagnosis and treatment. Muscle Nerve 40:10–18PubMedCrossRefGoogle Scholar
  61. 61.
    Kobbe P, Zelle BA, Gruen GS (2008) Case report: recurrent piriformis syndrome after surgical release. Clin Orthop Relat Res 466:1745–1748PubMedCrossRefGoogle Scholar
  62. 62.
    Konstantinou K, Dunn KM (2008) Sciatica: review of epidemiological studies and prevalence estimates. Spine 33:2464–2472PubMedCrossRefGoogle Scholar
  63. 63.
    Kosukegawa I, Yoshimoto M, Isogai S, Nonaka S, Yamashita T (2006) Piriformis syndrome resulting from a rare anatomic variation. Spine 31:E664–E666PubMedCrossRefGoogle Scholar
  64. 64.
    Kouvalchouk J, Bonnet JM, de Mondenard JP (1996) Piriformis syndrome. Apropos of 4 cases treated by surgery and review of the literature. [French]. Rev Chir Orthop Reparatrice Appar Mot 82:647–657PubMedGoogle Scholar
  65. 65.
    Ku A, Kern H, Lachman E, Nagler W (1995) Sciatic nerve impingement from piriformis hematoma due to prolonged labor [letter]. Muscle Nerve 18:789–790PubMedGoogle Scholar
  66. 66.
    Kumar B, Sriram KG, George C (2002) Osteophyte at the sacroiliac joint as a cause of sciatica: a report of four cases. J Orthop Surg (Hong Kong) 10:73–76Google Scholar
  67. 67.
    Lee EY, Margherita AJ, Gierada DS, Narra VR (2004) MRI of piriformis syndrome. Am J Roentgenol 183:63–64Google Scholar
  68. 68.
    Lewis AM, Layzer R, Engstrom JW, Barbaro NM, Chin CT (2006) Magnetic resonance neurography in extraspinal sciatica. Arch Neurol 63:1469–1472PubMedCrossRefGoogle Scholar
  69. 69.
    Liberati A, Altman DG, Tetzlaff J et al (2009) The PRISMA statement for reporting systematic reviews and meta-analyses of studies that evaluate health care interventions: explanation and elaboration. PLoS Med Accessed 27 March 2010
  70. 70.
    Limongelli P, Khorsandi SE, Pai M et al (2008) Management of delayed postoperative hemorrhage after pancreaticoduodenectomy: a meta-analysis. Arch Surg 143:1001–1007PubMedCrossRefGoogle Scholar
  71. 71.
    Lu MY, Dong BJ, Ma XY (1985) Piriformis syndrome and its operative treatment: an analysis of sixty cases. Zhonghua wai ke za zhi (Chinese journal of surgery) 23, 483-4, 510Google Scholar
  72. 72.
    Mayrand N, Fortin J, Descarreaux M, Normand MC (2006) Diagnosis and management of posttraumatic piriformis syndrome: a case study. J Manipulative Physiol Ther 29:486–491PubMedCrossRefGoogle Scholar
  73. 73.
    Merlo IM, Poloni TE, Alfonsi E, Messina AL, Ceroni M (1997) Sciatic pain in a young sportsman. Lancet 349:846PubMedCrossRefGoogle Scholar
  74. 74.
    Miller A, Stedman GH, Beisaw NE, Gross PT (1987) Sciatica caused by an avulsion fracture of the ischial tuberosity. a case report. J Bone Joint Surg Am 69:143–145PubMedGoogle Scholar
  75. 75.
    Mixter WJ, Barr JB (1934) Rupture of intervertebral disc with involvement of the spinal canal. N Engl J Med 211:110–115CrossRefGoogle Scholar
  76. 76.
    Molina N (2003) Piriformis syndrome. Dyn Chiropr Accessed 4 April 2010
  77. 77.
    Nakamura H, Seki M, Konishi S, Yamano Y, Takaoka K (2003) Piriformis syndrome diagnosed by cauda equina action potentials: report of two cases. Spine 28:E37–E40PubMedCrossRefGoogle Scholar
  78. 78.
    Ozaki S, Hamabe T, Muro T (1999) Piriformis syndrome resulting from an anomalous relationship between the sciatic nerve and piriformis muscle. Orthopedics 22:771–772PubMedGoogle Scholar
  79. 79.
    Pace JB, Nagle D (1976) Piriform syndrome. West J Med 124:433–439Google Scholar
  80. 80.
    Papadopoulos EC, Khan SN (2004) Piriformis syndrome and low back pain: A new classification and review of the literature. Orthop Clin North Am 35:65–71PubMedCrossRefGoogle Scholar
  81. 81.
    Papadopoulos SM, McGillicuddy JE, Albers JW (1990) Unusual cause of ‘piriformis muscle syndrome’. Arch Neurol 47:1144–1146PubMedGoogle Scholar
  82. 82.
    Papadopoulos SM, McGillicuddy JE, Messina LM (1989) Pseudoaneurysm of the inferior gluteal artery presenting as sciatic nerve compression. Neurosurgery 24:926–928PubMedCrossRefGoogle Scholar
  83. 83.
    Park HW, Jahng JS, Lee WH (1991) Piriformis syndrome—a case report. Yonsei Med J 32:64–68PubMedGoogle Scholar
  84. 84.
    Pecina HI, Boric I, Smoljanovic T, Duvancic D, Pecina M (2008) Surgical evaluation of magnetic resonance imaging findings in piriformis muscle syndrome. Skelet Radiol 37:1019–1023CrossRefGoogle Scholar
  85. 85.
    Pecina M (1979) Contributions to the etiological explanation of the piriformis syndrome. Acta Anat 105:181–187PubMedCrossRefGoogle Scholar
  86. 86.
    Pokorny D, Jahoda D, Veigl D, Pinskerov V, Sosna A (2006) Topographic variations of the relationship of the sciatic nerve and the piriformis muscle and its relevance to palsy after total hip arthroplasty. Surg Radiol Anat 28:88–91PubMedCrossRefGoogle Scholar
  87. 87.
    Raney EM, Freccero DM, Dolan LA et al (2008) Evidence-based analysis of removal of orthopaedic implants in the pediatric population. J Pediatr Orthop 28:701–704PubMedGoogle Scholar
  88. 88.
    Retzlaff EW, Berry AH, Haight AS et al (1974) The piriformis muscle syndrome. J Am Osteopath Assoc 73:799–807PubMedGoogle Scholar
  89. 89.
    Rich BSE, McKeag D (1992) When sciatica is not disk disease: detecting piriformis syndrome in active patients. Neurorehabil Neural Repair 20:104–108Google Scholar
  90. 90.
    Richardson RR, Garon JE, Sianis GJ (1992) Sciatic entrapment neuropathy by tendinized muscle—the pyriformis syndrome: a case report. J Neurol Orthop Med Surg 13:142–145Google Scholar
  91. 91.
    Robinson DR (1947) Pyriformis syndrome in relation to sciatic pain. Am J Surg 73:355–358PubMedCrossRefGoogle Scholar
  92. 92.
    Rodrigue T, Hardy RW (2001) Diagnosis and treatment of piriformis syndrome. Neurosurg Clin N Am 12:311–319PubMedGoogle Scholar
  93. 93.
    Rossi P, Cardinali P, Serrao M et al (2001) Magnetic resonance imaging findings in piriformis syndrome: a case report. Arch Phys Med Rehabil 82:519–521PubMedCrossRefGoogle Scholar
  94. 94.
    Rucco V, Onorato A (1998) Common pseudoradicular syndromes (pseudocrural and pseudosciatic pain). Europa Medicophysica 34:75–83Google Scholar
  95. 95.
    Sayson SC, Ducey JP, Maybrey JB, Wesley RL, Vermilion D (1994) Sciatic entrapment neuropathy associated with an anomalous piriformis muscle. Pain 59:149–152PubMedCrossRefGoogle Scholar
  96. 96.
    Silver JK, Leadbetter WB (1998) Piriformis syndrome: assessment of current practice and literature review. Orthopedics 21:1133–1135PubMedGoogle Scholar
  97. 97.
    Slipman CW, Vresilovic EJ, Palmer MA, Lipetz JS, Lenrow D (1999) Piriformis muscle syndrome: a diagnostic dilemma. J Musculoskelet Pain 7:73–83CrossRefGoogle Scholar
  98. 98.
    Soga J, Yakuwa Y, Osaka M (1999) Carcinoid syndrome: a statistical evaluation of 748 reported cases. J Exp Clin Cancer Res 18:133–141PubMedGoogle Scholar
  99. 99.
    Solheim LF, Siewers P, Paus B (1981) The piriformis muscle syndrome: sciatic nerve entrapment treated with section of the piriformis muscle. Acta Orthop Scand 52:73–75PubMedCrossRefGoogle Scholar
  100. 100.
    Spinner RJ, Thomas NM, Kline DG (2001) Failure of surgical decompression for a presumed case of piriformis syndrome. Case report. J Neurosurg 94:652–654PubMedCrossRefGoogle Scholar
  101. 101.
    Stegbauer CC (1997) Sciatic pain and piriformis syndrome. Nurse Pract 22:166–180Google Scholar
  102. 102.
    Stein JM, Warfield CA (1983) Two entrapment neuropathies. Hosp Pract 18:100A, 100E, 100HGoogle Scholar
  103. 103.
    Steiner C, Staubs C, Ganon M, Buhlinger C (1987) Piriformis syndrome: pathogenesis, diagnosis, and treatment. J Am Osteopath Assoc 87:318–323PubMedGoogle Scholar
  104. 104.
    Stevens KJ, Banuls M (1994) Sciatic nerve palsy caused by haematoma from iliac bone graft donor site. Eur Spine J 3:291–293PubMedCrossRefGoogle Scholar
  105. 105.
    Stewart JD (2003) The piriformis syndrome is overdiagnosed. Muscle Nerve 28:644–646PubMedCrossRefGoogle Scholar
  106. 106.
    Sutton AJ, Abrams KR, Jones DR, Sheldon TA, Song F (2000) Methods for meta-analysis in medical research. Wiley, LondonGoogle Scholar
  107. 107.
    Synek VM (1987) Short latency somatosensory evoked potentials in patients with painful dysaesthesias in peripheral nerve lesions. Pain 29:49–58PubMedCrossRefGoogle Scholar
  108. 108.
    Synek VM (1987) The pyriformis syndrome: review and case presentation. Clin Exp Neurol 23:31–37PubMedGoogle Scholar
  109. 109.
    Terrasa S, Caccavo T, Ferraris J et al. (2007) Guía para la lectura crítica de una Serie de Casos. Evidencia en la Práctica Ambulatoria. Accessed 4 April 2010
  110. 110.
    Tiel RL (2008) Piriformis and related entrapment syndromes: myth and fallacy. Neurosurg Clin N Am 19:623–627 viiPubMedCrossRefGoogle Scholar
  111. 111.
    Tiel RL, Kline DG (2006) Piriformis syndrome. J Neurosurg Spine 5:102–104PubMedCrossRefGoogle Scholar
  112. 112.
    Turtas S, Zirattu G (2006) The piriformis syndrome: a case report of an unusual cause of sciatica. J Orthop Traumatol 7:97–99CrossRefGoogle Scholar
  113. 113.
    Vallejo MC, Mariano DJ, Kaul B, Sah N, Ramanathan S (2004) Piriformis syndrome in a patient after cesarean section under spinal anesthesia. Reg Anesth Pain Med 29:X364–X367Google Scholar
  114. 114.
    van Tulder M, Becker A, Bekkering T et al (2006) Chapter 3. European guidelines for the management of acute nonspecific low back pain in primary care. Eur Spine J 15(Suppl 2):S169–S191PubMedCrossRefGoogle Scholar
  115. 115.
    Vandenbroucke JP (2001) In defense of case reports and case series. Ann Intern Med 134:330–334PubMedGoogle Scholar
  116. 116.
    Vandertop WP, Bosma NJ (1991) The piriformis syndrome. A case report. J Bone Joint Surg Am 73:1095–1097PubMedGoogle Scholar
  117. 117.
    Waddell G (2004) The back pain revolution. Churchill Livingstone, LondonGoogle Scholar
  118. 118.
    West S, King V, Carey TS et al. (2002) Systems to rate the strength of scientific evidence. Evidence Report/Technology Assessment Number 47. Accessed 4 April 2010
  119. 119.
    West D, Togo A, Kirk AJ (2007) Are bronchoscopic approaches to post-pneumonectomy bronchopleural fistula an effective alternative to repeat thoracotomy? Interact Cardiovasc Thorac Surg 6:547–550PubMedCrossRefGoogle Scholar
  120. 120.
    Wyant GM (1979) Chronic pain syndromes and their treatment. III. The piriformis syndrome. Can Anaesth Soc J 26:305–308PubMedCrossRefGoogle Scholar
  121. 121.
    Yoon SJ, Ho J, Kang HY et al (2007) Low-dose botulinum toxin type A for the treatment of refractory piriformis syndrome. Pharmacotherapy 27:657–665PubMedCrossRefGoogle Scholar
  122. 122.
    Young J (1999) Lung volume surgery (LVRS) for chronic obstructive pulmonary disease (COPD) with underlying severe emphysema, A West Midlands Development and Evaluation Committee Report. University of Birmingham, BirminghamGoogle Scholar
  123. 123.
    Yuen EC, So YT (1999) Sciatic neuropathy. Neurol Clin 17:617–631PubMedCrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2010

Authors and Affiliations

  • Kevork Hopayian
    • 1
    • 3
  • Fujian Song
    • 1
  • Ricardo Riera
    • 2
  • Sidha Sambandan
    • 1
  1. 1.School of Medicine, Health Policy and PracticeUniversity of East AngliaNorwichUK
  2. 2.Department of the MedicineUniversidad CaraboboValenciaVenezuela
  3. 3.AldeburghUK

Personalised recommendations