Semirigid instrumentation in the management of lumbar spine conditions combines with circumferential fusion. - Gertzbein,S.D.; Betz,R.; Clements,D.; Errico,T.; Hammerberg,K.; Robbins,S.; Shepherd,E.; Weber,A.; Kerina,M.; Albin,J.; Wolk,D.; Ensor,K. (Spine, 1996)