Objective: The objective of this retrospective review was to examine the impact that adding photobiomodulation therapy (PBMt) to rehabilitation therapy had on the pathology of degenerative myelopathy (DM) in canine patients. Background: Canine DM is a progressive, fatal neurodegenerative disease for which there exists a dearth of effective treatments, limiting clinicians to pursue symptom palliation. Methods: Clinical records of dogs referred for presumed DM to a specialty rehabilitation facility were screened for patients meeting study criteria. Qualifying patients were divided into two groups: Protocol A (PTCL-A) and Protocol B (PTCL-B) group, based on the PBMt protocol used. Data related to demographics, diagnostics, rehabilitation protocols, and progression of clinical signs were collected. Data were analyzed to determine differences in outcomes between the two treated groups and historical data expectations, as given by a previously published study. Results: The times between symptom onset and euthanasia of dogs in the PTCL-B group: 38.2-14.67 months (mean-SD), were significantly longer than those of dogs in the PTCL-A group: 11.09-2.68 months. Similarly, the times between symptom onset and nonambulatory paresis (NAP) or paralysis of dogs in the PTCL-B group: 31.76-12.53 months, were significantly longer than those of dogs in the PTCL-A group: 8.79-1.60 months. Further, Kaplan-Meier survival analysis showed that the times from symptom onset to NAP of dogs in the PTCL-B group were significantly longer than those of dogs in the PTCL-A group (Mantel-Cox Log Rank statistic = 20.434, p < 0.05) or the historical data group (Mantel-Cox Log Rank statistic = 16.334, p < 0.05). Conclusions: The data reviewed show significantly slower disease progression-longer survival times-for patients in the PTCL-B group than those in the PTCL-A group or published historical data. Further studies are warranted.

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