MYERS, S. A., MERSHON, C. E., & FUCHS, E. F. (1997). VASECTOMY REVERSAL FOR TREATMENT OF THE POST-VASECTOMY PAIN SYNDROME. The Journal of Urology, 157, 518–520.
Results: Of 32 men who underwent vasectomy reversal for the post-vasectomy pain syndrome between 1980 and 1994, 24 had relief of symptoms after the initial procedure. Of 8 men with recurrent pain 6 underwent a second reversal procedure, and 3 of them subsequently had relief of symptoms. Overall, 27 of 32 men had resolution of pain.
This is the paper which is cited when you see that 84% of men had relief from PVPS.