The aim of this study is to prospectively investigate the potential for bony fusion of ViviGen® bone graft substitute in comparison to rhBMP-2 in monosegmental ALIF procedure L5/S1 and in monosegmental XLIF procedure L4/5
Patients must be 18 - 70 years of age
Patients must have understood and signed the study information and the informed consent form
Patients are willing and able to complete scheduled follow-up evaluations / questionnaires as described in the Informed Consent
Patients under 18 years and over 70 years of age
Patients with tumour / spine trauma / known bone disease / Parkinson's disease and similar CNS disorders / diseases or injuries of the peripheral nerves
Other procedures or segment than mentioned in the inclusion citeriaAdditional planed spine surgeries after index surgery
Current smoking