**8.1 Degenerative disk disease**

Pettine et al. studied the use of intra-discal BMC injections in patients with DDD [131]. The authors injected 26 symptomatic patients for lumbar diskogenic back pain and disability and evaluated their postinjection outcomes using disability scores, pain scores, and MRIs. At 2-year follow-up, patients experienced significant improvements in disability and pain scores. This group was the first to report on MSC dose-dependent outcome responses. Patients receiving greater concentrations of autologous BM-MSC (expressed as CFU-Fs > 2000/ml) experienced a faster and greater reduction in pain scores. Later, these findings were strengthened with a follow-up study at 36 months, showing similar outcome results [43]. At 5-year follow-up, absolute and percentage reductions in pain and disability scores were sustained, with no adverse events reported through the 5-year follow-up period [132]. The American Society of Interventional Pain Physicians published recently guidelines addressing responsible and safe use of autologous biologics in the management of lower back pain [133]. Their extensive analysis revealed that there is level III evidence for the use of PRP and BM-MSCs. The guidelines also state that, following diagnostic evidence, regenerative therapies should be provided to patients as an independent therapy. If appropriate and indicated, regenerative therapies can be combined with conventional medicinal therapy or in conjunction with physical and behavioral therapy.
