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.