 The closure of an anti-oral fistula is one of the most perplexing problems encountered in oral surgical practice. When one considers the number of operations that have been proposed for this problem, as well as the variety of operations in use today, it is obvious that there is no unanimity of opinion in regard to this matter. Failure to adhere to certain cardinal surgical principles is possibly responsible for many of the difficulties encountered in the management of this problem. The first principle involved is elimination of infection from the maxillary sinus. No attempts should be made to close a fistula until the sinus is entirely clear of infection. Many of the unsuccessful attempts at closure possibly stem from failure to adhere to this important principle. The second principle is adequate soft tissue flaps. The soft tissue flaps must be large enough to cover the bony defect. It must be borne in mind that the bony defect is always larger than the soft tissue opening, and the soft tissue flaps must be adequate to cover the bony defect. The third principle involved is suture the flaps without tension. The flaps should be so designed that when they are sutured, there will be no tension on the suture lines, and the flaps will have no tendency to return to their original position. Adherence to these principles will ensure successful treatment in the majority of cases. Several methods utilizing these principles have been used successfully. Those most frequently used are the palatal flap, the use of tantalum or some similar metal, and the utilization of combination buckle and lingual flaps. For several years we have been using a buckle envelope type of flap with considerable success. This method provides for an ample flap that can be mobilized with ease, and when sutured in position forms a double thickness of tissue over the defect. It will be demonstrated in the present case. This large anteroral opening has been present since extraction of the posterior teeth six months ago. Two previous attempts have been made to close the fistula. The maxillary arch is a dentulous with evidence of recent extraction of the anterior teeth. The fistula extends directly into the left maxillary sinus. Probing of the defect reveals that a large oseous defect was present. Local or general anesthesia is satisfactory for this procedure. However, we most frequently use local anesthesia utilizing a second division block. This block is administered through the greater palatine foramen with an aspirating type syringe. The area of injection is dried, painted with an antiseptic solution, and the needle inserted directly into the greater palatine foramen. It is extended the full length of a 1-5-8 inch needle. Aspiration is accomplished, and if no blood is withdrawn into the syringe, the solution is injected. This injection produces complete anesthesia of the second division of the fifth nerve. The first step in the surgical procedure is an incision, beginning at the posterior aspect of the alveolar ridge, extending along the fistula on both sides, terminating well anteriorly. The incision at the margins of the fistula permits removal of the epithelial lining of the fistula's track. The next procedure is to de-epithelialize an area on the buccal surface. This area should be approximately 5 millimeters in width, and the epithelium should be removed down to the submicosal layer. This may be done by sharp dissection as is being demonstrated here, or it may be accomplished by one of the rotary-type instruments. This drawing shows the extent of de-epithelialization as it is being done by sharp dissection. The next step is to elevate the buccal and lingual flaps. These flaps are elevated until there is free mobility on both sides. The lingual flap is raised almost to the midline, and the buccal flap is high on the lateral surface of the maxilla as possible, and may even be extended on to the lateral surface of the zygoma. These flaps must be freely movable. The next procedure is to make a horizontal cut through the periosteum of the buccal flap. This cut is made as high as possible underneath the flap and is very shallow, merely going through the periosteum. This cut permits mobilization and movement of the buccal flap in a downward direction. The incision is made with a scapelle, and you will note that it extends the full length of the flap and is as high as possible. The next step is to eliminate all infectious material from the maxillary sinus. All patients with anteroural fistulas should be seen in consultation by an otorhinolaryngologist. For in fistulas of long-standing, there is frequently a conconimate chronic infection of the sinus that must be brought under control. In these instances of chronic infection, it is good judgment to make an antero nasal window to permit drainage of the sinus after the fistula has been closed. The antero nasal opening, which is made by the otorhinolaryngologist, is placed beneath the inferior turbinate and must be a sufficient size so it will stay patent. After the anteroural opening has been made, the next step is to clean out the maxillary sinus. A foreign body consisting of a large piece of alginate impression material was present in the sinus. It had undoubtedly gained entrance through the anteroural fistula at the time that impressions were made for a denture. The thickened sinus membrane is removed with curets until all pathological tissue has been eliminated. In anteroural fistulas of long-standing, large amounts of infectious material may be present and considerable attention must be given to its removal. After all pathologic tissue has been removed, the sinus is flooded with normal saline and inspected thoroughly for any residual infectious material. Too much emphasis cannot be given to the importance of completely eradicating all pathologic tissue from the sinus. After these procedures have been completed, the wound is ready for closure. The flaps have been sufficiently mobilized that they can be moved and sutured without tension. Horizontal mattress-type sutures are used, which are placed in such a manner that the de-epitheliized buckle flap is brought under the lingual flap. This is accomplished by starting the suture on the mucosal surface of the palatal flap, passing it through to the periosteal surface, then going from the de-epitheliized side to the periosteal side of the buckle flap, then back from the periosteal to the de-epitheliized side of the buckle flap, and finally bringing the suture back to the palatal flap, passing it from the periosteal to the mucosal surface. To emphasize this method of suturing, placement of another suture will be shown in detail. This forms a horizontal mattress, which, when drawn tight, will bring the buckle flap under the lingual flap. All of the sutures are inserted before any are tied. This is to facilitate the placement of the last sutures, which would be impossible if the previous sutures were tied at time of placement. After all sutures have been inserted, they are tied individually. An instrument tie starting at the posterior part of the wound and coming forward is utilized. Note that each suture is held by a hemostat, which facilitates the handling of the large number of sutures. Note that as the sutures are tied, the flap is readily drawn into the desired position without tension. When all sutures are tied, the buckle flap is held securely in place under the palatal flap. All knots are on the lingual. In this case, the de-epitheliized area was somewhat larger than necessary. Also note that placement of the sutures in this manner allows the margin of the lingual flap to remain free. This free margin is stabilized by placing additional sutures from the margin of the lingual flap to the buckle tissues. This completes the closure. The final closure is demonstrated in this illustration. Note the double layer closure over the area of the fistula. The horizontal cut in the buckle flap has separated to permit movement of this flap. To prevent excessive postoperative edema which might cause tension on the flaps, an extraoral pressure dressing is applied. This dressing consists of a gauze dressing over the left cheek, attached with adhesive tape that goes completely around the neck. This dressing gives additional support and will prevent undue tension to the flaps. To recapitulate, the first step is an incision around the opening, extending along the crest of the alveolar ridge approximately two to three centimeters, anterior and posterior to the fistula. The buckle macoza is deapothelialized for an area of about five millimeters. The lingual and buckle flaps are then elevated to give free mobility to both flaps. An incision is then made through the periosteum of the buckle flap, extending the entire length of the flap. This incision is made as high in the buckle flap as possible. Horizontal mattress sutures are then inserted. These sutures bring the buckle flap under the lingual flap. After all sutures have been inserted, they are then individually tied, which completes the closure. The finished closure produces a double thickness of tissue over the fistulus opening. The horizontal cut in the buckle flap, which allows movement of this flap, is demonstrated in this illustration. The sutures are left in place approximately 10 days. Healing is usually uneventful and rapid. One month post-operatively, complete healing of the fistula has occurred. While there has been minimal shortening of the buckle vestibule, it did not interfere with the construction and function of satisfactory maxillary and mandibular dentures. It must be emphasized that there are no shortcuts to the successful closure of persistent anteroral fistula and strict adherence to detail is essential. Attention to the surgical principles of one, elimination of infection, two, adequate soft tissue flaps, and three, suturing these flaps without tension is necessary. In our hands, the utilization of the buckle envelope type of flap has been very successful in the management of this problem.