Closure of Schneiderian Membrane Perforation and Placement of Two Implants During a Sinus Lift Surgery

A sinus lift surgery is a method of a vertical dimension augmentation in a posterior maxillary alveolar process with the purpose of one-stage or deferred implantation upon its severe atrophy and/or significant pneumatization of the maxillary sinus.

Now the sinus lift surgery is a well researched, safe, and documented procedure, which is highly popular among dentists. At the same time, separation of maxillary sinus mucous membrane from its walls is quite a delicate procedure and sometimes the membrane breakage during a surgery with defects happens. Literature shows that the percentage of Schneiderian membrane perforations during sinus lift surgeries varies from 11% to 56%. (Ardekian, 2006).

This kind of an operative complication often bewilders surgeons and sometimes even makes them stop the surgery and proceed with it just in some time. But it should be clear that during the following attempts to repeat the surgery, the risk of the scar tissue perforation does not become reduced. Moreover, the size of the perforation hole can be significantly bigger because of the Schneiderian membrane elasticity loss. In view of this, some methods of mucous membrane defect closure have appeared providing an opportunity to continue and complete the surgery within one stage. Moreover, if mucous membrane defect closure is conducted right, the mere fact of perforation does not affect the implant survival. (Schwartz Arad D, 2004).

Various methods of Schneiderian membrane perforation closure during a sinus lift surgery have been suggested. Most of them are based on collagen membrane utilizing.

In the following clinical case a big perforation in mucous sinus membrane appeared. For that reason, the ‘parachute’ method has been applied for conducting the defect closure along with one-stage placement of Bio3 Progressive implants.

Clinical Case

A patient, 32 years old, complained of missing teeth in the area of the left maxilla. The medical history showed that the teeth had been extracted because of caries complications 5 years ago. It also appeared that the patient had been smoking for 10 years. So the patient was warned about possible risks and complications of implantation and sinus lift surgery connected with smoking.

Objectively: During the oral cavity examination, a bounded edentulous space in the posterior left maxilla between the teeth 2.4 and 2.7 was found. CBCT of the maxilla and the defect area showed that the height of the bone tissue between the maxillary sinus floor and the jaw ridge bone was from 4 to 6mm, which was not enough for implant placement without penetration into the maxillary sinus space.

CBCT
CBCT of the posterior left maxilla. The left maxillary sinus is significantly pneumatized, an alveolar opening in the area of the missing tooth 2.5 is observed

The bone tissue volume presented was not enough for placement of a minimal implant without a sinus lift surgery, but the bone volume available permitted conducting sinus lift simultaneously with implant placement. The decision was taken to conduct a sinus lift surgery with simultaneous placement of 2 implants Bio3 Progressive 11.5/3.8.

The surgery process: Using local anesthesia with DS-Forte Ultra Cain solution, after the processing of the operative field with an antiseptic (Chlorhexidine bigluconate), and L-shaped cut was made on the mucous membrane, in the area of the alveolar process of the left maxilla, along the alveolar process top and through the gingival space near the teeth 2.4, 2.6.

posterior maxilla
The cut in the area of access to the alveolar process of the posterior maxilla

The zygomatic alveolar crest was skeletonized with an elevator. The bone tissue was thinned with the help of a special diamond bur until its mucous membrane was seen (Schneiderian membrane).

sinus
The view of the released alveolar process and the lateral wall of the left maxillary sinus: the area of the sinus has more light grey contours and less bleeding points (marked with a dotted line)
sinus wall
A ‘lateral window’ formation in the sinus wall with the help of a diamond bur
Schneiderian membrane
Schneiderian membrane (the sinus membrane) with a small number of vessels in it is seen through the cut

Then the attempt to separate the mucous sinus membrane from its bone walls was made with the help of an antral curette set, which resulted in a perforation appearance in the anterosuperior part of the space.

mucous sinus
Separation of the mucous sinus membrane from its bone walls with the help of an antral curette
perforation hole
The view of the perforation hole in the partially separated mucous membrane of the posterior sinus

Despite the complication, the separation of the Schneiderian membrane from the lower and medial sinus walls was continued, the sinus membrane was mobilized to the most in the area of the posterior, medial, and lower walls. The patient’s blood collection was made and PRF-membranes were prepared.

PRF-membranes
PRF-membranes and collagen membrane

The perforation hole was closed with PRF- and collagen membranes according to the ‘parachute’ method.

PRF-membrane
The view of PRF-membranes put under the Schneiderian membrane
Collagen membrane
Collagen membrane put across the PRF-membranes and pulled outside

Implants Bio3 Progressive 3.8/11.5 were inserted into the preliminary prepared sockets for the alveolar process width.

Bio3 Progressive implants
Bio3 Progressive implants partially inserted for the purpose of further filling of the socket with the osteoplastic material

The space between the membrane and the bone walls of the sinus was partially filled with the mixture with PRF.

PRF-blobs and PRP
Mixture mixed with PRF-blobs and PRP

After that full insertion of implants into augmentation and bone tissue of the alveolar process, as well as filling of the residual cavity with the osteoplastic material were conducted.

osteoplastic material
The view of the implant fully inserted and the final filling of the sub antral space with the osteoplastic material

Some part of the collagen membrane was pulled out of the lateral window and covered with a mucoperiosteal flap, the wound was sewn up tightly with Nylon thread 4.0. A comparison CBCT of the operative area was conducted.

Nylon thread
Tight sewing up of the wound with Nylon thread. A healing abutment was placed into the implant in the area of the tooth 2.5 to prevent its displacement towards the sinus cavity
CBCT
The comparison CBCT of the sinus operated

For the postoperative period antibacterial and anti-inflammatory therapy as well as vasoconstrictive medication for the left side of the nasal cavity were prescribed, to prevent blocking of the natural anastomosis in the maxillary sinus.

Closure of Schneiderian Membrane Perforation and Placement of Two Implants During a Sinus Lift Surgery

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