How is a synechiae operation to breath better performed?

A synechiae release operation is internal, and depending on the position of the septum and turbinates may require adjustment in position of both.
At the end of surgery, silicon sheets are placed inside the nostrils to prevent contact between the lateral wall and midline and reduce the chance of the problem occurring again. They will often be left in place for 1-3 weeks depending on the magnitude of the problem and the protocol that the surgeon follows.

Thank you for you for your question. I would recommend Rhinoplasty with the latest Ultrasonic Rhinoplasty device Piezo®:

In traditional Rhinoplasty, surgical instruments known as rasps and osteotomies (hammer and chisel) are used to reshape the nasal bones by removing the hump and/or narrowing the nasal bone width. These tools are relatively imprecise and their use can lead to contour irregularities, etc. if not used in the proper manner. Recently, a technology that uses sound waves has been developed to contour nasal bones in a precise and far less traumatic way when compared to traditional techniques. Ultrasonic, or Piezo, Rhinoplasty is now the most advanced technology available for minimally traumatic nasal bone reshaping and hump removal during Rhinoplasty. There will be hardly any bruising and swelling which will make the recovery period a lot easier for the patient. our question.

Synechiae are scar tissue bands that form in the nose, usually due to previous surgery.  They can also result from trauma, cocaine use, nasal cautery, etc.  These are scars that are located inside the nose. Cutting them dose not require external incisions. This is a question that is more appropriate for the surgeon who is going to perform the operation , not for strangers on the internet.  Your surgeon should be able to describe in detail the surgical plan prior to performing the procedure.  If you are describing a cosmetically small nostril, that's a different problem.