[Therapeutic and diagnostic classification of degenerative spondylolisthesis: validation and multiple-center inter-observer agreement].

Object: To evaluate inter- and intra-observer agreement of the proposed diagnostic and treatment classification of degenerative spondylolisthesis.

Material and methods: The proposed diagnostic and treatment classification of degenerative spondylolisthesis was validated according to the GRRAS protocol. For this purpose, we retrospectively analyzed MRI, CT and spinal radiography data in 20 patients. Inter- and intra-observer agreement was carried out by 11 experts from 6 federal institutions of Russia. Fleiss and Cohen's kappas were calculated using the Statistical Package for the Social Sciences (SPSS), version 21.0 (SPSS Inc., Chicago, IL, USA).

Results: Validation was carried out in two stages. The first stage (3 experts from one clinical unit): inter-observer agreement k (Fleiss)=0.863 [0.786; 0.939]; intra-observer agreement - Cohen's kappa >0.81 (expert 1 - k=0.931, expert 2 - k=0.908, expert 3 - k=0.862). The second stage was multiple-center and included 11 experts. Inter-observer agreement k(Fleiss) was 0.792 [0.767; 0.817]. We compared agreement among surgeons with comparable experience depending on specialty: orthopedic - k=0.799 [0.774; 0.814]; neurosurgeons - k=0.791[0.769; 0.817] (p=0.687). Surgeon's experience did not affect significance of classification: <10-year experience - k=0.781 [0.767; 0.798], >10-year experience - k=0.808 [0.789; 0.817] (p=0.287).

Conclusion: The presented diagnostic and treatment classification of degenerative spondylolisthesis has significant inter- and intra-observer multiple-center and multidisciplinary agreement. Integration of classification into clinical practice will allow standardization of surgical tactics for degenerative spondylolisthesis.