Accessory instruments

TTTS. Accessory instruments

Accessory ports (2 mm) and blunt probes can be particularly useful under specific circumstances. Accessory ports may be required to pass sidefiring laser fibers or blunt probes to complete surgery in some patients with anterior placentas. 

Blunt probes may be used to displace the donor twin to allow visualization of vascular anastomoses that may be blocked by this fetus. Although not often used, these accessory instruments may be critical in the completion of surgery in certain patients. 

Pressure/volume regulation 

The typical amniotic fluid pressure in patients with TTTS is 10–15 mmHg.12 It is also known that the amniotic fluid pressure rises linearly by 1 mmHg/L of physiological fluid infused.13 This is inconsequential in TTTS, as patients where exchange of the amniotic fluid is necessary due to bloody or vernix discoloration of the fluid rarely receive 1000 ml without being exchanged. More commonly, an even exchange of amniotic fluid can be performed through the trocar and trumpet as described above. Therefore, it is not necessary to monitor amniotic fluid pressure during surgery for TTTS.