What happens when you close an “open roof” from dorsal hump shaving?

However it is very good and commendable you try to understand this concept, the most common cause for a revision rhinoplasty; I'll be brief and plain:
-the nasal pyramid is like a tent of a house's gable roof
-if you chop away part of that roof, aka the nasal hump... you get an open roof with exposed walls' edges
-you have to move the walls together to create a new roof (who wants the rain to pour into the living room?); that is done by fracturing THE BASE of the roof, very near the maxilla (so that the infracturing is invisible) and moving both walls together in contact to each other and allowing healling between them

Failing to do so after removing the hump leads to a typical and inevitable combo:
-open roof deformity: ridges of the walls (and the septum) are visible through the skin, gaps between them visible too like two slots, also broad dorsum (the larger the hump removed the broader the resulting dorsum)
-inverted V deformity: the soft walls of the nose made of cartilage at the lower half of the glable roof do close spontaneously the roof, no need for fracturing, however they close too much and fall inwards the septum, dislocating themselves from the non-fractured nasal bones and hence creating a gap with an inverted V shape

Hope I helped to clarify this very important concept, known since 1905 when Dr. Joseph invented rhinoplasty (he taught all us about the open roof and the need of infracturing). See below at the link a longer explanation.

PS: You may wonder... why surgeons fail to do the osteotomies if this is such A-B-C lesson nº1 of rhinoplasty?... easy... fear and incompetence.

The bridge of most people's noses is very narrow at the apex, and Broad at the base, where it meets the cheeks. Whenever we remove a bump in the operating room, we notice a widening of the dorsal nasal appearance. This is called creating an open roof deformity. We close the open roof deformity with osteotomies, To bring the sidewalls of the nose back into the midline and to provide narrowing. I hope this answers your question, and I wish you well moving forward. Sincerely, Dr Joseph

Hello and thank you for your question. To treat an open roof deformity osteotomies can help close the open roof, and then either a fascial only graft or morselized bone dorsal onlay graft can also be added to help provide a smoother dorsal contour. I recommend that you seek consultation with a qualified board-certified rhinoplasty surgeon who can evaluate you in person.

Best wishes and good luck.

Richard G. Reish, M.D.
Harvard-trained plastic surgeon

The infracture of the nasal bones brings them together closer to the septum and upper lateral cartilages which fixes the open roof. Sometimes spreader grafts are placed to correct that area as a precaution.
Regards
Dr. Janjua