title: Recovery of severe motor deficit secondary to herniated lumbar disc prolapse: is surgical intervention important? A systematic review.
abstract: BACKGROUND
  The natural history of motor deficit due to lumbar disc herniation has been thought to be favourable. However, on closer analysis of seminal articles on this topic, this is not the case for patients with severe motor deficits (MRC grade ≤3). The aim of this study is to answer the following questions: (1) Is surgical intervention beneficial in patients with severe motor weakness (defined by MRC grade of 3 or less) due to herniated lumbar nucleus pulposus? (2) Does time to surgery from onset of motor weakness influence the outcome? (3) Are there any other prognostic factors?
  
  
  METHODS
  A comprehensive search was conducted in MEDLINE and EMBASE from 1970 upto July 2013. Inclusion criteria for studies are: (1) minimum of three patients aged 18 and older, who had symptomatic herniated lumbar disc prolapse and underwent surgery, (2) description of pre and post-operative muscle weakness utilising the Medical Research Council (MRC) muscle power grade or equivalent, such that both reviewers could confidently identify a cohort of patients with at least grade three motor weakness or worse, (3) a minimum of 6 months follow-up.
  
  
  RESULTS
  Seven studies were identified with a total of 354 patients. Complete recovery was seen in 38.4% of patients following surgery and 32% following non-operative treatment. Age and grade of motor deficit were identified as significant prognostic factors in some of the studies.
  
  
  CONCLUSIONS
  The current available evidence is not robust enough to address the questions posed. We have proposed a framework for future studies.
authors.affiliation: Royal National Orthopaedic Hospital, Brockley Hill, Stanmore, Middlesex, HA7 4LP, UK, arjibalaji@gmail.com.
authors.forename: V R
authors.initials: VR
authors.lastname: Balaji
authors.forename: K F
authors.initials: KF
authors.lastname: Chin
authors.forename: S
authors.initials: S
authors.lastname: Tucker
authors.forename: L F
authors.initials: LF
authors.lastname: Wilson
authors.forename: A T
authors.initials: AT
authors.lastname: Casey
mesh_terms: D004525:Efferent Pathways; D006801:Humans; D007405:Intervertebral Disc Displacement / Q000150:complications / Q000601:surgery*; D008159:Lumbar Vertebrae / Q000601:surgery*; D018908:Muscle Weakness / Q000209:etiology / Q000601:surgery*; D011379:Prognosis; D011391:Prolapse; D020127:Recovery of Function; D013123:Spinal Fusion / Q000009:adverse effects*