I just wanted to shortly share my experiences. I think someone with a similar situation might get help from this; I had three SP infections in a 5-month period during 2013-2014.
Each time I got the SP emptied and antibiotics to go. After the last occurence, I finally met a surgeon. She told the sinus holes are not clearly visible. Since she could not find them, she was not sure exactly where to operate. Hence, the operation would require quite a large wound. I decided not to go forward with a trial-and-error -style operation, so I tried a different approach. Since the SP symptoms only appeared after having an open wound in the cleft, my wife, who is a nurse, thought I should try shielding the cleft with a suitable special tape. I tried a tape called Mepitac (http://www.molnlycke.us/wound-care-dressings/fixation-retention/mepitac/#confirm). I have now been using this tape daily for over a year, and I have not had a single SP episode since.
Each day, after shower, I put a ~1.5″ (ca. 5cm) tape in the cleft, which keeps the skin intact. This tape method will probably not work for patients with clear openings i.e. sinus holes, but if the situation is similar to mine, it’s worth a try!