Spastic pelvic floor syndrome and puborectalis syndrome: the different stages of the same disease.

Purpose: The diagnosis and treatment of puborectalis syndrome (PRS) and spastic pelvic floor syndrome (SPFS) are still up for debate. This study aims to investigate and examine the similarities and differences between PRS and SPFS.

Methods: This study recruited 13 PRS cases, 10 SPFS cases, and 16 controls. Pelvic magnetic resonance imaging (MRI), histology, and ultrastructural pathology were explored. Additionally, anorectal manometry was performed prior to surgery, and Wexner constipation scores and patient assessment of constipation quality of life (PAC-QOL) scores monitored before surgery and 6 and 12 months post-surgery.

Results: The puborectalis thickness in the pelvic MRIs of the SPFS and control groups did not appear to differ (4.62 ± 0.38 vs 4.56 ± 0.47, p = 0.378); however, the puborectalis in the PRS group was substantially thicker than that of the SPFS (8.65 ± 1.17 vs 4.62 ± 0.38, p < 0.001). The SPFS group showing atrophy and degeneration of muscle fibers and the PRS group exhibiting necrosis of muscle fibers, both groups had distorted texture myofibrils, disorganized arrangement, and rough Z lines; however, in severe cases of PRS group, localized myofibrils fracture and myofilament dissolution presenting as vacuolation. Patients with normal preoperative rectal propulsion force had improvements in postoperative Wexner constipation scores and PAC-QOL scores.

Conclusion: Histological and ultrastructural pathological evidence suggests that SPFS and PRS are distinct phases of paradoxical puborectalis syndrome (PPS). Furthermore, one indication for PPS surgical treatment is normal rectal evacuation pressure.