Main findings
Though, USA Food and Drug Administration had a press announcement
concerning the long-term safety10, TVM is still an
option for POP reconstruction because it offers satisfied anatomical and
objective outcomes12. In contrast to studies
consistently demonstrating advantages of TVM on the
voiding19,20, the current study explored the potential
benefit of TVM to the storage function by specifically focusing on the
bladder compliance.
Our results reveal TVM post-operatively increased bladder compliance of
POP patients, namely the bladder displayed a reduced pressure in
response to the storage volume during the filling stage. The
TVM-increased compliance could benefit POP patients, because aberrantly
elevated intra-vesical pressure during storage is deleterious as it
would cause vesico-ureteral reflux2, over-activate the
micturition reflex21, and result in stress urinary
incontinence22.
Notably, in contrast to urodynamic studies analyzing the bladder
compliance by dividing the change in volume by that in pressure
(C=ΔV/ΔP); and thereby offer a mean value of compliance over the entire
filling stage23, a recent study exploring compliance
dynamics has demonstrated PVA not only graphically and conceptually
assesses the bladder compliance but also provides a protocol that is
able to specifically analyze compliance of targeted periods during
bladder filling18.
PVAs in this study demonstrates while the post-operative trajectory
displayed a relatively constant slope during entire filling, the
pre-operative trajectory markedly deviated to the right and downwards at
the late filling stage, indicating the compliance was decreased
specifically at this stage. The decreased compliance in the late filling
of pre-operative patients was confirmed as the patient statistically
displayed a lower C2/2 compared to C1/2. Even though a clear-cut value
defining a low bladder compliance waits to be established, studies have
reported a level of low compliance in human from 12.5 to 40
ml/cmH2O3,24,25. Considering our mean C1/2 before TVM
were 105.82±16.41 ml/cmH2O, a value far higher than these levels, we
suggest the impaired compliance in POP patients is possibly attributed
to the compliance decrement at the late filling.
On the other hand, while the TVM-increased Cm was associated with
post-operatively enhanced C2/2, the C1/2 remained relatively unaffected
after the procedure. Together with that the post-operative Cm
(103.01±13.44 ml/cmH2O), C1/2 (116.13±12.92 ml/cmH2O), and C2/2
(112.84±21.57 ml/cmH2O) in this study were all higher than the reported
level of low compliance, these findings collectively reveal TVM benefits
to the storage function of POP patients by specifically ameliorating the
impaired compliance during the late filling.