This systematic review and meta-analysis focused on measuring the effectiveness of the TC-DCR in the treatment of PANDO. TC-DCR was compared with EX-DCR in terms of its efficacy in achieving anatomical success, functional success, fewer intraoperative complications, fewer postoperative complications, and a shorter surgical time. Our study included ten studies comprising six observational studies, two quasi-experimental studies, and one RCT that compared TC-DCR to EX-DCR.

First, our systematic review and meta-analysis demonstrated that EX-DCR resulted in significantly higher anatomical success rates than did TC-DCR, as there was a 16% decrease in the chance of TC-DCR achieving anatomical success. Similar results have been reported previously. Uludag et al. [18] reported that EX-DCR achieved significantly better anatomical success than did TC-DCR (89.5% to 73.3%, respectively). Bulut et al. [21] also confirmed that EX-DCR was significantly superior to TC-DCR in achieving anatomical success (94.1% and 58.0%, respectively). Furthermore, in our analysis, while EX-DCR had a statistically significant advantage over single-diode DCR, it had a statistically insignificant advantage when EX-DCR was compared with multi-diode TC-DCR. Moreover, EX-DCR showed an overall statistically significant advantage compared to TC-DCR.

Additionally, our study showed that EX-DCR had a significantly better functional success rate than TC-DCR as there was a 13% decrease in the chance that TC-DCR would achieve functional success. Bulut et al. [21] reported that EX-DCR had a significant advantage in terms of functional success compared with TC-DCR. Their study reported a functional success rate of 91.1% for EX-DCR and 54.8% for TC-DCR. Recent studies by Yener et al. [20] and Mutlu et al. [22] also agreed with our outcome; however, the results were not statistically significant. Yilmaz et al. [17] also discussed that multi-diode TC-DCR and EX-DCR had similar anatomical and functional success rates and that further studies are needed.

Moreover, TC-DCR had a significantly shorter OR time. These results are consistent with those reported in the literature. Yeniad et al. [6], Çömez et al. [15], Yilmaz et al. [17], and Bulut et al. [21] all concluded that TC-DCR has a significantly shorter mean OR time (21.4 min, 22.2 min, 20.3 min, and 27.9 min, respectively) than EX-DCR (56.2 min, 56.3 min, 46.6 min, and 58.5 min, respectively).

With respect to intraoperative complications, TC-DCR has also been shown to be associated with fewer complications, with statistical significance. This result is in agreement with that reported in the literature. Çömez et al. [15] reported a statistically significant difference when the TC-DCR was superior. In their study, two patients who underwent TC-DCR experienced intraoperative complications with middle turbinate injury, whereas 14 patients who underwent EX-DCR suffered from intraoperative bleeding. They also reported that with more intraoperative complications, the surgery time would increase; therefore, fewer intraoperative complications associated with TC-DCR contribute to a shorter surgical time. In addition, the hospitalization and healing times are lengthy.

Lastly, postoperative complications were fewer in the EX-DCR group as there was a 44% increase in the risk of post op complications for TC-DCR; however, this result was not statistically significant. This outcome contradicts the findings reported by Mourya et al. [19] reported. They reported that TC-DCR had a postoperative complication rate of 20.7%, whereas EX-DCR had a rate of 27.6%. However, Yilmaz et al. [17] and Bulut et al. [21] agreed with our analysis, with TC-DCR having 36.7% and 9.7% postoperative complications, respectively, while EX-DCR had 21.2% and 0%, respectively. However, complications have been under-reported in previous studies, which may lead to underestimation in both approaches.

While looking at the articles, we noticed that the study conducted by Uludag et al. [18] in 2015 was a follow-up to a study that Yeniad et al. [6] conducted in 2012. After three years, some outcomes have changed. In the original study, the anatomical success rates of TC-DCR and EX-DCR were 84.2% and 89.4%, respectively, and the difference was not statistically significant. However, in a follow-up study, the anatomical success rates for TC-DCR and EX-DCR were 73.7% and 89.4%, respectively, and these differences were statistically significant [18].

A systematic review and network meta-analysis were performed to assess the success rates of EX-DCR, endonasal-DCR, and TC-DCR with or without silicone tubes. Their study revealed no difference between endonasal, external, and transcanalicular lasers without silicone tube insertion. In addition, their study showed that TC-DCR with silicone tube insertion is inferior to endonasal and external methods with or without silicone tubes [23]. When comparing TC-DCR with silicone to TC-DCR without silicone, a study by Goel et al. showed no difference between the two approaches [24]. However, these results should be interpreted with caution, as only three studies with small sample sizes from these studies assessed the TC-DCR without silicone.

As some doctors and patients prefer TC-DCR because of the aesthetic reason of not leaving a visible scar, reduced operation time, and minimal complications and risk of bleeding [14, 19, 21], further studies on TC-DCR should be conducted to develop further and optimize this technique to provide higher-quality medical care and increase patient satisfaction.

The study was conducted in a straightforward manner. First, in this study, we raised the question of whether multi-diode TC-DCR is a superior option to single-diode TC-DCR. Second, we used a large sample size to address this issue.

Although we carried out our best efforts to produce high-quality studies, we had several limitations. First, no previous standard or baseline data were available for patients. Second, some of the included studies did not report all intraoperative or postoperative complications. Third, we could not assess the use of silicone tubes across the studies. Finally, the paucity of information pertaining to the ethnicity of the patients included in the studies could potentially elucidate the presence of anatomical diversities. This, in turn, may give rise to intraoperative complications or modifications in the duration of surgical procedures.