Surgically treated degenerative cervical spine diseases in twins.

PURPOSE: Genetic factors are considered important in the development of degenerative spine disease. The aim of this study was to determine the twin concordance rates for the common cervical spine diseases cervical disk herniation (CDH), cervical foraminal stenosis (CFS), and degenerative cervical myelopathy (DCM) requiring surgical treatment by studying monozygotic (MZ) and dizygotic (DZ) twin pairs.

METHODS

Patients, aged 18-85 years, operated for CDH, CFS, or DCM between 1996 and 2022 were identified in the national Swedish spine register (5962 CDH, 3801 CFS, and 3131 DCM) and matched with the Swedish twin registry to identify MZ and DZ twins. Concordance rates were calculated.

RESULTS

There were 64 twin pairs where one or both twins had surgical treatment for CDH. The corresponding numbers for surgically treated CFS and DCM were 37 twin pairs and 44 twin pairs respectively. For twins with CDH we found one concordant MZ pair and no concordant DZ pair (MZ probandwise concordance rate 0.12 [95% CI 0-0.33]). For twins with CFS we found one concordant MZ pair and no concordant DZ pair (MZ probandwise concordance rate 0.14 [95% CI 0-0.38]). In DCM patients we found no concordant twin pair.

CONCLUSIONS

In this national observational study, including 145 twin pairs, the concordance rates were low for surgically treated CDH, CFS, and DCM conditions. Our findings suggest that not only genetic factors, but also environmental factors and personal preferences are important whether a patient goes to surgery for this type of condition.