Sinus augmentation surgery has made significant advances over recent years. The biggest advances have been a progression toward minimally invasive surgery. Traditional methodology, where large lateral wall osteotomies are followed by packing cadaver graft material, has been shown to result in 50% of grafts becoming infected that either require prolonged antibiotics or the need to remove the graft material in 5% of sinus augmentations. Not only is minimally invasive surgery less traumatic on the patient, but reducing the size of the osteotomy and delivering the graft material via sterile delivery systems eliminates post operative infections when the sinus membrane stays intact. The large lateral wall osteotomy filled with cadaver bone graft was a tremendous innovation, but like all of healthcare, continued refinement and surgical skill has resulted in less trauma and higher success rates. Minimally invasive sinus augmentation surgeries require significant surgical skill to perform and irrespective of the type of access to the sinus, these surgeries require an intact sinus membrane to be successful. Over the last 15 years, SteinerBio has been developing and improving minimally invasive sinus augmentations, but it remained that handling the sinus membrane is the main challenge. No matter what type of access, some sinus membranes are so fragile that any contact can destroy a delicate membrane. Over the years when a membrane was damaged, we would remove the membrane and graft with Sinus Graft. In these cases, nothing covered the grafted material in the sinus. It was these occasional cases that taught us that we were able to achieve superior results with fewer complications simply by removing the sinus membrane. At this time, the sinus membrane removal technique is how we now perform all sinus augmentations before grafting and implant placement. The following cases show how we have progressed with this methodology.
Sinus Augmentation with
Sinus Membrane Removal
Initially, the approach was to perform a small lateral wall osteotomy to access the sinus. However, we have progressed to using the implant osteotomy as shown in this photograph. The implant osteotomy is prepared, and the sinus is first entered with an angled spoon to remove the sinus membrane from the floor of the sinus.
Grafting complete. Because the graft material is exposed, it sets in the sinus just as it sets outside of the body. The material will be hard in approximately 30 minutes. The implants are best placed immediately after grafting while the material is still soft. When the graft material sets, it bonds to the bony surfaces where the membrane was removed.
3 months post op at healing abutment appointment. The entire graft material will be resorbed at this time while the new bone has integrated to the implant surface. During this phase of bone regeneration, the bone is woven. However, once the implant is loaded, the woven bone will remodel into lamellar bone.
Pre-op. One implant is planned for native bone in the bicuspid region and two implants in the sinus with sinus augmentation. Distal to the two planned sinus implants, a mucous retention cyst is noted. The bone on the floor of the sinus varies between 1 and 2 mm in thickness. The bone on the lateral wall of the maxilla was very thin and transparent showing a dark sinus. A lateral wall minimally invasive sinus augmentation was planned. However, as soon as the wall of the sinus was contacted with the bur, the sinus membrane was perforated with no ability to retain the membrane. The decision was made to remove the sinus membrane and leave the mucus retention cyst in place.
Day of sinus membrane removal, grafted with Sinus Graft and implant placement. The anterior implant is in native bone and the two distal implants are in 1 to 2 mm of crestal bone. The vertical orientation of the implants was determined by the position of the crest. Because only 1 to 2 mm of crest holds the implants, care must be taken as to not stress the thin crestal bone. The osteotomies must be full diameter because under-drilling in an attempt to increase implant stability will likely fracture the crest when the implants are placed. The patient is instructed to completely avoid applying any pressure for the first month post-op to prevent intrusion of the implants into the sinus. The mucous retention cyst is covered with graft material.
11-year post-op At this time period, the distal implant has developed mesial marginal bone loss. This does not appear to be periimplantitis as no inflammation is present. The cause of the bone loss is undetermined, but there could be a relationship between the coronal placement of the distal implant and the alveolar bone. Alveolar bone always seeks to be level and the change in levels of the coronal position of the implants may over time affect the marginal bone. Another thing to note in this series is when grafting sinuses with Sinus Graft, normal bone is produced and this bone will remodel in time. While the initial graft material and bone is most always above the apex of the implants, over time the bone resorbs to the apex of the implant and stops. Apparently, load of the implant is needed to maintain the level of the regenerated bone in the sinus.
Over the years of using this methodology when a sinus membrane cannot be utilized, we have had no implant failures and no post operative complications. As a result, we are now removing the sinus membrane for all sinus augmentation surgeries. The simplicity of this methodology reduces the level of skill required to perform predictable sinus augmentation, shortens the time required to perform the surgery, and significantly reduces post-op morbidity. The time between grafting and implant placement and restoration is dependent on the amount of residual crestal bone, but in most cases the implants can be restored in 3 months.
American Society for Bone and Mineral Research (ASBMR) Tissue Engineering and Regenerative Medicine International Society (TERMIS)