An assessment of the reliability of the Enneking and Weinstein-Boriani-Biagini classifications for staging of primary spinal tumors by the Spine Oncology Study Group.
METHODS
Reliability analysis based on expert panel case series review and grading per the Enneking and Weinstein-Boriani-Biagini classification systems.


OBJECTIVE
To assess the reliability of the Enneking and Weinstein-Boriani-Biagini classification systems.


BACKGROUND
The Enneking and Weinstein-Boriani-Biagini (WBB) classifications were developed to stage and facilitate treatment planning in patients with primary spine tumors. To date, their interobserver and intraobserver reliability has not been assessed-a fundamental step in facilitating broader clinical and research use.


METHODS
Clinical information, imaging studies, and biopsy results were compiled from 15 selected patients with primary spinal tumors. Eighteen spine surgeons independently estimated and scored the cases for Enneking grade, tumor and metastasis categories, Enneking stage, Enneking-recommended surgical margin, WBB zones and layers, and WBB-recommended surgical procedures, with a second assessment performed after random resorting of cases. Interobserver and intraobserver reliability of each category were assessed by percent agreement or proportional overlap. The Fleiss, Cohen, and Mezzich kappa statistics (kappa) were then applied, determined by the type of variable analyzed.


RESULTS
The kappa statistics for interobserver reliability were 0.82, 0.22, 0.00, 0.57, 0.47, 0.31, 0.58, and 0.54 for the fields of Enneking grade, tumor and metastasis categories, Enneking stage, Enneking-recommended surgical margin, WBB zones and layers, and WBB-recommended surgical procedures, respectively. The kappa statistics for intraobserver reliability were 0.97, 0.53, 0.47, 0.82, 0.67, 0.63, 0.79, and 0.79 for the same respective fields. According to Landis and Koch, the ranges of kappa values of 0.00 to 0.20, 0.21 to 0.40, 0.41 to 0.60, 0.61 to 0.80, and >0.80 imply slight, fair, moderate, substantial, and near-perfect agreement, respectively.


CONCLUSIONS
Results indicate moderate interobserver reliability and substantial and near-perfect intraobserver reliability for both the Enneking and WBB classification in terms of staging and guidance for treatment, despite a less than moderate interobserver reliability in interpreting the Enneking local tumor extension and WBB sector. Before incorporating the classifications in the clinical practice and research studies, further work is required to investigate the validity of the classifications.
Chan
Patrick
P
Vancouver General Hospital, Vancouver, Canada.
Boriani
Stefano
S
Fourney
Daryl R
DR
Biagini
Roberto
R
Dekutoski
Mark B
MB
Fehlings
Michael G
MG
Ryken
Timothy C
TC
Gokaslan
Ziya L
ZL
Vrionis
Frank D
FD
Harrop
James S
JS
Schmidt
Meic H
MH
Vialle
Luis R
LR
Gerszten
Peter C
PC
Rhines
Laurence D
LD
Ondra
Stephen L
SL
Pratt
Stuart R
SR
Fisher
Charles G
CG
D001706:Biopsy; D001938:Brazil; D002170:Canada; D005260:Female; D006801:Humans; D007558:Italy; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D009367:Neoplasm Staging / Q000379:methods*; D019635:Neurosurgical Procedures; D015588:Observer Variation; D018579:Patient Selection; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D013125:Spinal Neoplasms / Q000145:classification / Q000473:pathology* / Q000601:surgery; D014057:Tomography, X-Ray Computed; D014481:United States