title: Assessing the outcomes of spine surgery using global positioning systems.
abstract: METHODS
  Pilot study.
  
  
  OBJECTIVE
  To examine whether surgical outcomes can be assessed objectively by advanced tracking technology, based on Global Positioning Systems (GPS).
  
  
  BACKGROUND
  Outcome studies are the commonest way to assess the results of surgical procedures. The success of these efforts is impeded by a number of factors, including the lack of valid outcome measures, difficulty in assessing changes in patients' expectations (response shift) and confounding effects of secondary gains.
  
  
  METHODS
  The measurement of walking speed, distances, and number of walking events per day, claudication index (maximal walking distance), characteristics during motorized trips, and the amount of time spent outdoors were monitored in 2 patients undergoing spine surgery for several weeks using advanced tracking technologies.
  
  
  RESULTS
  In 1 patient, all parameters increased progressively from the time of surgery to the end of the recording period. These findings were consistent with her recovery from surgery. In a second patient, tracking showed the patient's difficulty in mobilizing, leading to the diagnosis of another orthopedic problem, and to total hip replacement surgery.
  
  
  CONCLUSIONS
  The technology presented in this pilot appears to be useful in understanding a patient's level and breathe of activity. These data will assist in better understanding the limitations imposed by specific musculoskeletal pathology and in monitoring perioperative function and complications and their related causes. Spatial data may indirectly reflect a patient's social and mental conditions. This interdisciplinary pilot may lead to the development of valid outcome measures for a range of medical conditions. Studies comparing questionnaires to this new outcome measure may shed light on issues like response shifts and secondary gain. Norms and clusters of spatial behaviors in different pathologies may enable better patient selection for medical, mental, and surgical interventions.
authors.affiliation: Department of Orthopedic Surgery, Hadassah Hebrew University Medical Center, Jerusalem, Israel. dbar@hadassah.org.il
authors.forename: Yair
authors.initials: Y
authors.lastname: Barzilay
authors.forename: Barzilay
authors.initials: B
authors.lastname: Yair
authors.forename: Shoval
authors.initials: S
authors.lastname: Noam
authors.forename: Liebergall
authors.initials: L
authors.lastname: Meir
authors.forename: Auslander
authors.initials: A
authors.lastname: Gail
authors.forename: Birenboim
authors.initials: B
authors.lastname: Amit
authors.forename: Isaacson
authors.initials: I
authors.lastname: Michal
authors.forename: Alexander R
authors.initials: AR
authors.lastname: Vaccaro
authors.forename: Kaplan
authors.initials: K
authors.lastname: Leon
mesh_terms: D000368:Aged; D017586:Diskectomy; D005260:Female; D040362:Geographic Information Systems; D006801:Humans; D008875:Middle Aged; D019637:Orthopedic Procedures / Q000379:methods*; D017063:Outcome Assessment, Health Care / Q000379:methods*; D010865:Pilot Projects; D020127:Recovery of Function; D015203:Reproducibility of Results; D013122:Spinal Diseases / Q000503:physiopathology / Q000601:surgery*; D013123:Spinal Fusion; D013997:Time Factors; D016138:Walking