Discussion
Although various medicine and even HPV vaccines have been tried to be
applied to adjuvant therapy for RRP, mainstay of treatment has largely
been surgical, which has evolved from microdebrider and other cold
instruments to include certain types of laser instruments over the past
few decades.
Microdebrider is a dynamic
rotational dissection device with suction assist, which has become the
preferred treatment for handling JO-RRP in recent years. Microdebrider
can easily push the mass away from the base and suck up, remove the mass
accurately, cause it can easily reach the throat and trachea under the
laryngoscope. Patel[12] noted in a retrospective study that the
operation time was significantly shortened since the CO2 laser switched
to microdebrider, with the advantages of saving surgical costs, avoiding
the risk of airway burns that may occur during laser surgery and the
possibility of vaporization of virus
particles. Microdebrider may replace
CO2 lasers, the preferred method of airway clearance in these patients,
and become the surgical modality of choice for RRP in some institutions.
In addition, microdebriders may be a more cost-effective tool for
removing bulky diseases than lasers alone, that’s why it has become the
main surgical modality to treat Jo-RRP. Go a step further, Huang[13]
notes that the surgeons prefer to use microdebrider for bulky tumors and
use KTP laser peeling technique for near-normal structure. This mixing
mode can help surgeons shorten surgery time and make it easier to
control bleeding, and it may avoid injury to the stratified structure of
the vocal cords. Actually, microdebrider has some drawbacks. Hemostasis
is an issue with cold techniques, but the surgical field of
microdebrider could remains clear most of the time due to the suction of
the connection[14].
CO2 laser was applied to the treatment of RRP as early as the early
1970s, which replaced the traditional cold instrument, and gradually
become a recognized treatment method for laryngeal diseases. The
wavelength of the CO2 laser (10 600 nm) is absorbed by water, allowing
the lesion to evaporate with a high percentage of intracellular
water[15]. However, CO2 laser operation is time-consuming,
expensive, and potentially dangerous of airway burning. One of the most
serious risk factors is airway combustion, normal tissue burns and
medical staff damaged If the intraoperative procedure is improper.
Unlike the CO2 laser, the angiolytic laser uses the peak in the
absorption spectrum of the oxygen hemoglobin rather than water, which
helps to selectively ablate the vascularized lesion without excessive
thermal damage. As a kind of the angiolytic laser, KTP laser seems has
great advantages in RRP resection, due to the blood-rich nature of
RRP[16]. In other words, the KTP laser can better preserve the
surrounding tissue and hemostasis control. Huang[13] revealed that
serial KTP laser procedures can effectively control RRP while preserving
phonatory function and maintaining adequate voice quality through a
longitudinal follow-up study. Burns[17] also demonstrated that
diseases in the anterior commissure of glottis can be treated with
minimal risk of scarring or adhesions, whether using KTP lasers alone or
as a complement to other surgical modalities, with minimal preservation
of the potential superficial intrinsic layer.
There have been few studies that directly compare the effects of
different surgical modalities on RRP recurrence rates. The results of
our study are consistent with these studies. Hock[16] analyzed the
Derkay score improved between first and last procedure in group of three
surgical modalities(KTP, CO2, and microdebrider), and found no
significant difference among the three treatment groups. Preuss[18]
suggested no correlation between the recurrence rate and surgical
modalities. However, these studies lacked a unified indicator of
effectiveness, and did not compare the three surgical modalities in
Jo-RRP and Ao-RRP separately.
Patients with RRP often need to undergo repeated surgeries, which is a
heavy financial burden. Medical institutions have started transferring
the performance of some procedures from the operating room to the
office, which would theoretically result in substantial savings. The
flexible CO2 wave-guide laser has been developed and commercially
available for several years, which can transfer surgery in the operating
room to the office under local anesthesia[19]. A study of Ao-RRP
case series concluded that office procedures are significantly more
cost-effective than operating room procedures, but their use may be
limited by patient tolerance and the increased frequency of the
procedure[20].
In our study, treatment intervals and recurrence trends did not differ
across three subgroups in both Jo-RRP and Ao-RRP patients, that is to
say, three surgical modalities appeared to be equally effective in terms
of controlling the recurrence of RRP. Therefore, the same recurrence
rate control effect can be achieved using microdebrider for medical
institutions without laser equipment. More attention should be paid to
other factors such as the economic cost, availability and complications
of surgery in decision-making of the surgical modality, which should be
further investigated. In addition, Derkay score was used to grade the
lesion anatomy to ensure the comparability between different groups,
which was rarely used in previous reports. Studies in the future would
require detailed reporting of disease burden, so that patients could be
risk stratified by group. Pre-op and post-op Derkay scores or other
consisten quantitative metrics are necessary, to accurately stage the
bulk and severity of disease to allow for more standardized reporting of
disease.
There are several limitations to
this study. First, this is a retrospective cohort study, we couldn’t
collect detailed case information in a completely random manner.
Secondly, we did not investigate the outcome of complications because
most patients may have undergone multiple surgeries. Future studies
should conduct more randomized controlled tests and include
postoperative complications in statistics to determine the best surgical
modalities.