4 Discussion
The present meta-analysis was conducted to evaluate the differences
between the SC and MC techniques after TL for laryngeal cancer in the
existing English literature. According to our meta-analysis, the SC
group demonstrated a significantly shorter operative time than the MC
group. In addition, we observed a lower incidence of PCF and hospital
stay after SC. The differences in postoperative surgical site infection
was not significant between groups with different closure techniques.
The pooled results from the analysis demonstrated that the operative
time for TL is approximately 45.9 to 63.2 minutes shorter with the SC
technique than with the MC technique. The result is intuitive because
the surgical stapler device is capable of dividing and closing
pharyngeal tissue simultaneously and instantly. In contrast, closure of
the pharyngeal defect by suturing after removal of the larynx is a
time-consuming step during TL. Ozturk et al reported that the closure
time needed for the pharyngeal mucosa was only 3.0 minutes with a
surgical stapler. However, it takes 37.5 minutes for surgeons to perform
a watertight closure of the pharynx by hand 16.
Several studies also indicated that prolonged surgical time was
significantly associated with a higher rate of postoperative
complications in patients undergoing TL 17-19.
Pharyngeal closure with a surgical stapler can therefore be a
time-saving technique for TL patients and potentially reduce the related
complications. One important step in the SC technique is to ensure that
the epiglottis is not trapped between the jaws of the surgical stapler.
There are different strategies to solve this problem. Some authors
retracted the epiglottis with an Allis clamp from the trachea lumen
below with or without an endoscopic field of view10,11,13,15. Some suggested that a small midline
pharyngotomy at the suprahyoid region enables the epiglottis to be
pulled anteriorly under direct vision without tapping it in the
pharyngeal mucosa 14,20.
TL is a life-saving procedure for individuals diagnosed with advanced
laryngeal cancer or those suffering from recurrence after organ
preservation treatment 21. However, permanent
tracheostomy, speech difficulty and altered swallowing may adversely
affect patients’ physical and emotional health 22.
Among all the complications after TL, PCF is most commonly reported and
is related to a prolonged hospital stay as well as delayed adjuvant
therapy 23. In the present meta-analysis, the
incidence rates of PCF in the SC group and MC group were 13.7% (28/204)
and 27.2% (90/331), respectively. The incidence of PCF was
significantly lower in the SC group. Two possible explanations exist for
the reduced incidence of PCF in the SC group. First, six of the enrolled
studies used the closed technique10-13,15,16, while
the remaining study used the semiclosed technique14when performing stapler closure of the pharynx. None of the SC groups in
each study used the open technique, which involves the removal of the
laryngeal specimen first and then the closure of the free edges of the
pharyngotomy with a stapler. By avoiding the creation of a large
pharyngeal defect before closure, the risk of surgical field
contamination by pharyngeal secretions can be minimized with the use of
a surgical stapler 10,11,13. Second, blood supply to
the surgical wound is believed to be fundamental to the healing process
after TL. However, repeated trauma by forceps and focal ischemia from
the tightening of sutures may both jeopardize the microcirculation of
the pharyngeal mucosa during MC 10,11. On the other
hand, the SC technique may be able to preserve more blood supply with
simultaneous stapling as well as cutting of the pharynx, which may be
beneficial to a better healing process. Radiotherapy24-27 and tracheostomy24,28 before
TL have both been identified as independent factors that are associated
with a higher rate of PCF. However, the pooled prevalence of patients
receiving preoperative tracheostomy and radiotherapy was significantly
higher in the SC group. The pooled results implied that the SC technique
has the potential to decrease the rate of PCF formation after TL even in
irradiated or tracheostomized patients.
The pooled results demonstrated that the length of hospital stay after
TL was approximately 2.9 days shorter in the SC group than in the MC
group and this probably reflected the different rate of postoperative
PCF between the two groups. Because of the lower PCF incidence with the
SC technique, more patients may be able to try oral feeding earlier and
reduce their length of hospital stay. Using a surgical stapler to close
pharyngeal defects during TL can prevent pharyngeal content from
contaminating the operative field. Theoretically, a reduced surgical
site infection rate is expected in the SC group. However, the results of
the present meta-analysis did not support this idea, and the rate of
surgical site infection was comparable between the SC and MC groups. One
possible reason may be that surgical site infection is a multifactorial
complication. Factors such as the general health status of the patient,
a lower serum albumin level, peri-operative blood transfusion and
operation time can all be associated with the rate of infection29,30.
This study had several limitations. First, only seven studies were
included in this meta-analysis. More studies are needed to confirm the
pooled results. Second, although some of the included articles were
randomized studies, retrospective studies were also included because of
the lack of available data in the current literature. Third, the
analysis of funnel plots and Egger’s tests demonstrated no obvious
evidence of publication bias. However, the results of this meta-analysis
should be interpreted with caution because of the heterogeneity between
the included studies. Despite these limitations, our meta-analysis still
provides evidence for the use of different closure techniques in TL.