title: Piriformis syndrome versus radiculopathy following lumbar artificial disc replacement.
abstract: METHODS
  Case series.
  
  
  OBJECTIVE
  To describe the presentation, diagnostic challenges, and treatment of five patients with piriformis syndrome after lumbar artificial disc replacement.
  
  
  BACKGROUND
  Until recently, spinal fusion was considered the standard for surgical treatment of severe lumbar degenerative disc disease. However, artificial disc replacement now offers an alternative solution. Piriformis syndrome results from entrapment of the sciatic nerve at the greater sciatic notch, with symptoms of pain and numbness radiating from the buttock to the foot, mimicking radiculopathy.
  
  
  METHODS
  In this case series, we report five patients who developed piriformis at our institution after artificial disc replacement.
  
  
  RESULTS
  Five patients, aged 35 to 46 years, developed some or all of the following symptoms in the affected leg after artificial disc replacement: posterior leg and buttock pain, calf weakness, and toe and ball of foot numbness and tingling. The onset of symptoms ranged from 6 days to 8 months postoperative, and became debilitating over time. Each patient was diagnosed with piriformis syndrome through physical examination. Three of the patients received a piriformis injection and reported 50% to 100% pain relief lasting 1 to 3 weeks. The patients subsequently underwent physical therapy that provided relief of their piriformis syndrome-related pain and enabled them to resume their normal activities.
  
  
  CONCLUSIONS
  Piriformis syndrome has not previously been described in the literature as a sequela of lumbar artificial disc replacement. Our case series indicates that this complication may be underdiagnosed. Careful consideration after artificial disc replacement is required if the patient presents with buttock, leg or foot pain, and/or numbness. It is important for physicians to recognize the symptoms of piriformis syndrome and to differentiate piriformis syndrome from nerve root compression and irritation or referred pain from spinal structures. Although controversial, the proper diagnosis of piriformis syndrome may have prevented some of these patients from undergoing unnecessary surgical procedures.
authors.affiliation: Spine Center, University of Colorado, Denver, Colorado, USA.
authors.forename: Elizabeth S
authors.initials: ES
authors.lastname: Robinson
authors.forename: Emily M
authors.initials: EM
authors.lastname: Lindley
authors.forename: Peter
authors.initials: P
authors.lastname: Gonzalez
authors.forename: Susan
authors.initials: S
authors.lastname: Estes
authors.forename: Robert
authors.initials: R
authors.lastname: Cooley
authors.forename: Evalina L
authors.initials: EL
authors.lastname: Burger
authors.forename: Vikas V
authors.initials: VV
authors.lastname: Patel
mesh_terms: D000328:Adult; D019643:Arthroplasty, Replacement / Q000379:methods*; D017586:Diskectomy / Q000379:methods; D005260:Female; D006801:Humans; D007403:Intervertebral Disc / Q000601:surgery*; D008159:Lumbar Vertebrae / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D055958:Piriformis Muscle Syndrome / Q000150:complications / Q000601:surgery*; D011843:Radiculopathy / Q000209:etiology / Q000601:surgery*; D016896:Treatment Outcome