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Page 8 of 10 Tokairin et al. Mini-invasive Surg 2020;4:32 I http://dx.doi.org/10.20517/2574-1225.2020.23

Figure 10. Subcarinal lymph node dissection via a transhiatal approach under pneumomediastinum. The middle to lower mediastinal
lymph nodes, including the subcarinal lymph nodes, are dissected under pneumomediastinum via a transhiatal approach

We consider the “crossover technique” to be useful for the dissection of the lymph nodes near the bilateral
main bronchus because these lymph nodes are located in the deepest area via both the cervical and
transhiatal approaches.

After the pneumomediastinal procedure, the bilateral remnant cervical paraesophageal lymph nodes and
supraclavicular lymph nodes are dissected using an open method.

The median total number of dissected lymph nodes in the cervico-mediastinal region identified with a
mediastinoscope was 36 (range 22-76) in 10 cases treated using the MELD procedure in our institute.

Postoperative outcomes
This operation using the bilateral cervical approach under pneumomediastinum was performed for 10
cases. The median mediastinoscopic operation time was 312 (299-336) mins and the median blood loss was
476 (203-667) mL. The median postoperative stay was 15.5 (14.0-16.8) days.

DISCUSSION
The MELD procedure is considered to have several advantages over other approaches. First, this procedure
does not require one-lung ventilation or a prone position. Second, this procedure requires only bi-cervical
and abdominal ports, thus no thoracic wounds are made, and the surgical wounds are very small. Finally,
the view via the right transcervical approach under pneumomediastinum is similar to that via the right
transthoracic approach.

Concerning the surgical outcomes, the blood loss was slight, and the postoperative stay was short. In
addition, dissection of the mediastinal lymph nodes using our MELD procedure was not inferior to
[22]
that with thoracoscopic esophagectomy . These results and the known benefits thus indicate that this
procedure is promising and expected to become prevalent in the near future.

However, this procedure is considered to have some disadvantages as well. This procedure requires a
long operation time, and recurrent nerve palsy is more frequently observed than with thoracoscopic
[10]
esophagectomy . In our institute, recurrent nerve palsy was recognized in about 40% of cases treated
with this procedure. However, most cases recovered within six months. We speculate that recurrent nerve
palsy occurred for reasons such as extension of the recurrent nerve and crush injury of the recurrent
nerve. Evaluating the recurrent nerves and improving the surgical procedure using NIM nerve monitoring
[23]
systems is expected to help prevent recurrent nerve palsy .