Accuracy and reproducibility of a retrospective outcome assessment for lumbar spinal stenosis surgery.
BACKGROUND
Retrospective assessment of surgery outcome is considered problematic. The aims of this study were to evaluate the reproducibility and accuracy of a retrospective outcome assessment of lumbar spinal stenosis surgery with reference to prospective outcome scale measurements.


METHODS
Outcome of surgery from 100 lumbar spinal stenosis (LSS) patients was evaluated retrospectively from patient files of a 3-month outpatient visit performed according to a standard clinical protocol by two independent researchers. In the retrospective analysis, outcome was graded as 2 = good if the clinical condition had clearly improved, 1 = moderate if it had just slightly improved, 0 = poor if it had not improved or was even worse than before the surgical treatment (Retrospective 3- point scale). A prospectively assessed Oswestry Disability Index questionnaire (ODI), Visual analogue pain scale (VAS) and a patient satisfaction questionnaire were used as references of standards. Reproducibility of the measurements was evaluated.


RESULTS
The retrospective 3-point scale correlated with ODI (r = 0.528; P < 0.001) and VAS (r = 0.368; P < 0.001). The agreement was better in the good and poor outcome than in the moderate outcome. Retrospective 3-point scale demonstrated substantial intra-rater and inter-rater repeatability (κ = 0.682, P < 0.001 and κ = 0.630, P < 0.001, respectively).


CONCLUSIONS
Retrospective assessment of spinal surgery outcome is highly reproducible. Accuracy is highest in the patients with poor and good surgical result.
Department of Neurosurgery, Kuopio University Hospital, Kuopio, Finland. pekkaku@student.uef.fi
Pekka
P
Kuittinen
Timo Juhani
TJ
Aalto
Tapani
T
Heikkilä
Ville
V
Leinonen
Sakari
S
Savolainen
Petri
P
Sipola
Heikki
H
Kröger
Veli
V
Turunen
Olavi
O
Airaksinen
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019299:Decompression, Surgical; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D008159:Lumbar Vertebrae / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D010045:Outpatients; D010146:Pain / Q000209:etiology / Q000473:pathology / Q000601:surgery; D010147:Pain Measurement; D018579:Patient Selection; D015203:Reproducibility of Results; D012189:Retrospective Studies; D013130:Spinal Stenosis / Q000150:complications / Q000473:pathology / Q000601:surgery*; D016896:Treatment Outcome