Discussion
A considerable proportion of patients with BPH ultimately undergo
surgical treatment for BPH and, recently, laser prostatectomy has been
increasingly selected 1,
2, 20.
However, even though surgical treatment for BPH has been performed, a
recent study reported that about a half of patients with BPH are still
treated with medication due to the persistent LUTS6. In this regard,
current clinical guidelines recommend a number of preoperative
examinations 21.
However, even though these examinations are performed, it is not easy to
accurately predict the postoperative symptomatic improvement, and some
novel parameters for predicting improvements in postoperative storage
symptoms after laser surgery are needed due to the impairment of storage
symptoms after laser prostatectomy as mentioned above. To the best of
our knowledge, this is the first study to report the prevalence of
decreased bladder compliance in patients with BPH who underwent laser
prostatectomy and to evaluate the impact of bladder compliance on
functional outcomes after laser prostatectomy.
In the previous study, the bladder compliance has been reported to
decrease as men age 22,
which is consistent with the findings of the current study. In that
study, about 1 out of 5 patients showed decreased bladder compliance
regardless of its severity, and about 1 out of 33 patients showed
bladder compliance < 12.5 mL/cmH2O among
patients with BPH who opted for laser surgery. In these men with bladder
compliance <12.5 mL/cmH2O, preoperative
subjective symptoms, especially storage symptoms, were impaired compared
to men with bladder compliance > 25
mL/cmH2O. which is in accordance with previous study.
These relations thought to be came from increased detrusor overactivity
in men with poor bladder compliance23. Although decreased
compliance could be related with the neurogenic bladder, in the current
study, the prevalence of neurological or cerebrovascular diseases was
not associated with bladder compliance, which might be due to the
exclusion of patients with moderate to severe neurogenic bladders who
were generally regarded as not optimal candidates for BPH surgery. In
addition, in this study, bladder compliance was negatively associated
with prostate volume or bladder outlet obstruction, in accordance with a
previous study 24,
25. A previous study also suggested that
BPH-induced decreased bladder compliance could be due to collagen
deposition in the bladder smooth muscle fiber26.
The findings of the study suggest that as preoperative bladder
compliance decreased, more improvements in storage symptom could be
expected at long-term follow-up. However, interestingly, storage symptom
was similarly improved regardless of the degree of bladder compliance at
the short-term or mid-term follow-up, i.e., at 1 and 12 months
postoperatively. Relief from of
BPH seemed to be helpful for improving storage symptoms induced by
decreased bladder compliance, although a few years are needed to realize
these improvements, which was consistent with a previous study27. This could also be
supported by another previous study demonstrating that restoration of
bladder compliance was not significantly observed at 6 months after
surgery 28. These
findings might be related to the elimination of collagen deposition in
the bladder smooth muscle fiber after resolving bladder outlet
obstruction; however, this hypothesis needs to be validated in a future
study. In addition, based on the results of the current study,
clinicians could be more interested in the laser surgery for BPH in men
with severe storage symptoms and decreased bladder compliance.
However, because storage symptom
was similarly improved regardless of the bladder compliance until 1
year, the clinicians should be careful for offering laser surgery in
these patients with decreased bladder compliance by expecting immediate
improvement in storage symptoms. In other words, clinicians should not
avoid laser surgery in men with severe lower urinary symptoms because of
the low bladder compliance, because storage symptoms might be alleviated
with the time. One concern was that the effects of bladder compliance on
functional outcomes might be not equivalent according to surgical
methods. Based on the current
study, HoLEP seemed to be superior compared to PVP regarding long-term
voiding and storage symptom improvements, which might come from large
removal of the prostate. However, the differences in storage sub-score
outcomes according to surgical methods seemed to be minimized compared
to voiding sub-score. In other words, compared to voiding sub-score,
impacts of laser prostatectomy on long-term storage functional outcomes
according to bladder compliance seemed to be similar regardless of
surgical methods.
In addition, based on this study, bladder compliance < 12.5
mL/cmH2O was thought to be a reliable and reasonable
cut-off value for predicting long-term functional outcomes after laser
prostatectomy. This was because bladder compliance with 12.5–25
mL/cmH2O showed similar improvements for subjective
symptoms compared to the bladder compliance ≥ 25
mL/cmH2O. Although several cut-off values for bladder
compliance have been suggested17,
18, none of these cut-off values have
been validated in patients with BPH who underwent laser prostatectomy.
Furthermore, the results of the current study need to be validated in a
future study with a larger number of patients and longer follow-up
duration.
There
were several limitations in the current study in addition to its
retrospective design. Due to the long study period, the selection of the
surgical methods may have changed, and this may affect the results of
the current study. In addition, a relatively high drop-out rate through
the long-term follow-up after surgery may have inadvertently created a
selection bias. However, the results of the current study could be
useful for clinicians to properly predict and explain surgical outcomes,
especially in men with decreased bladder compliance.