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Page 8 of 9 Brandolini. Mini-invasive Surg 2020;4:45 I http://dx.doi.org/10.20517/2574-1225.2020.27

DISCUSSION
The aim of thymectomy in patients with myasthenia gravis (MG) is the complete removal of the thymus
and perithymic tissue to eradicate all immunogenic thymic cells and potentially viable thymic tissue in
patients with MG to minimize disease persistence or increasing relapse rates. In cases of malignancy when
a thymoma is diagnosed, it is still crucial to achieve radical en bloc excision of the residual thymic gland to
improve both overall survival and the risk of local recurrence.

With a left-sided approach for thymectomy, dissection of fat tissue in the right cardio-phrenic angle and
within the confluence of the superior vena cava and innominate vein can be difficult, while the resection
of the thymus gland with fat tissue in the left cardio-phrenic angle and at the level of the aorto-pulmonary
window may be limited with a right-sided approach. On the contrary, the bilateral view improves the
approach to the left innominate vein and offers a clear and close view of both phrenic nerves. Moreover, the
bilateral view might be especially helpful in thymomas.

An additional cervical incision within the neck may be helpful for a more extended excision of all residual
thymus at the level of the upper cervical poles but in our experience, the bilateral VATS technique can
safely achieve radical dissection of both superior thymic horns. Some sort of bilateral view, especially of the
controlateral phrenic nerve, might be achieved by adding a sub-xyphoid port to the unilateral approach (see
below).

We believe that correct positioning of the trocars and the patient’s position are crucial to facilitate surgical
dissection, avoid instrumental conflicts within the thorax and to reduce operating time. We routinely
use an energy-based tissue sealing device during the whole procedure (ultrasound or radiofrequency are
equivalent depending on personal experience and preference) for tissue handling, dissection and sealing
vessels (Keynes veins).

[11]
Among the various minimally invasive approaches, the subxiphoid thymectomy described by Kido et al.
in 1999 is gaining interest and popularity among thoracic surgeons. The two main advantages of this
approach are reduction of postoperative pain and cosmetic results because of the small incisions (1 or
[12]
2 ports for access) and the possibility to avoid intercostal nerve damage. As shown by Suda et al. ,
in comparison with a lateral VATS approach, the subxiphoid thymectomy is associated with reduced
consumption of postoperative analgesics and perioperative blood loss. A similar operative time was
[12]
observed in the two groups . This technique seems to be able to overcome some technical difficulties of
the VATS operation, such as the small working space, different viewpoint from a median sternotomy and
bilateral phrenic nerve control. On the other hand, the subxiphoid approach is not widely used because of
its unfamiliarity among thoracic surgeons and difficult intraoperative control of bleeding in the event of
major vessel injury such as bleeding of the left innominate vein.

The definition and indications for VATS thymectomy in the treatment of early-stage thymomas are
[13]
summarized in the ITMIG reccomandations . Some authors disagree with a minimally invasive approach
for large tumours because the dissection might be difficult and tumor manipulation might translate into
[14]
intraoperative seeding of the pleural space, which would compromise the procedure .

Nevertheless, some earlier studies comparing robotic-assisted thymectomy with trans-sternal thymectomy
showed that large thymic tumors can be managed by the robotic approach, which has improved three-
dimensional visualization, increased freedom of instrument motion for precise dissection and permits
radical dissections, even of thymomas > 4 cm in diameter, while reducing the risk of capsular injury and
[15]
providing all the benefits in postoperative recovery of the minimally-invasive approach to the patient .