Regarding the importance of preserving annular integrity, this study showed progressive loss of disc height following discectomy reaching 26% by end of two years. No doubt the decrease in disc height would have continued after the study.
A prospective cohort study of close interval compu... [Spine (Phila Pa 1976). 2009] - PubMed result
Recently the following study was published, presenting a modified suturing technique that has been tested to effectively close annular defects, promote annular healing, and delay/prevent disc height loss and degeneration following discectomy. Five Phd researchers were involved in the development and testing.
The Effect of a New Anular Repair After Discectomy in Interv... : Spine
There is also currently a Phase III clinical trial under way of the X close annular repair system by Anulex.
Anulex: Preservation and Anular Repair
I wonder whether these annular repair techniques might also be compatible with the numerous biologic gels and tissues developed in recent years that promote sealing and healing of annular defects. Combining the physical and biological approaches might facilitate a very fast healing and strong repair allowing the patient to get back to their life without risk of needing a future ADR or fusion due to progressive disc collapse.
Also, percutaneous nucleus replacement might become a desirable procedure where annular integrity can be assured.
As these approaches would not be as lucrative as fusion or ADR there may be limited motivation for industry to develop or pursue them.