Journal of Dental Implantology -
Complications After Maxillary Sinus Augmentation: A Case Report
By JDI editor
Published on 04/3/2009
Mohamed A. Maksoud, DMD
Private Practice, Jacksonville, Florida, USA.

The maxillary sinus grafting procedure has been routinely performed with predictable results. The procedure has proven to be an acceptable modality for bone augmentation to provide a base for endosseous implant placement. Several complications have been documented in the literature. They vary from sinus membrane perforation to formation of a mucocele inside the bony graft mass. This report describes a serious complication after a maxillary sinus augmentation that resulted in obliteration of the sinus.

Case report.
Mohamed A. Maksoud, DMD
Private Practice, Jacksonville, Florida, USA.

Caldwell-Luc procedures, which were introduced by Tatum1 and Misch,2 involve the formation of an osteotomy window on an antral wall of the maxillary sinus. After the infarction of the osteotomy, careful and gentle elevation of the schneiderian membrane is accomplished to avoid a perforation. This is usually followed by placement of the graft material to the desired bony height that will eventually encompass the implant body. A number of clinicians have also documented predictable use of the procedure in an attempt to increase the vertical height of available bone for implant placement. Several investigators have studied different bone graft materials. However, several complications during and after the completion of a sinus grafting procedure have been demonstrated in the literature. The most common complication is perforation of the schneiderian membrane, which has been classified by investigators and is usually curable with the use of collagen membrane. Mucocele formation has also been reported as an intrabony radiolucency within the bony mass. This is benign and asymptomatic. Chronic sinusitis, infection, loss of the graft material, and failure of the implant to integrate are other reported complications.

A 53-year-old man presented to the office for a consultation, seeking evaluation of previously grafted maxillary sinuses with multiple complications and for implant insertion in the maxilla to replace an ill-fitting maxillary full denture. The patient had bilateral sinus grafting done by a surgeon one year ago and claims that the surgeon used iliac crest bone autograft. Review of the medical history was noncontributory, and there were no current medications. Review of the surgical notes provided by the surgeon revealed bilateral sinus augmentations using iliac crest autograft mixed with bovine bone xenograft.
The notes revealed no reported complications at the time of the surgery. However, after the surgery, the patient complained of vague pain on the right side that increased when he lowered his head. This pain was associated with frequent headaches.
The patient also reported continuous congestion in the right maxillary sinus with frequent yellow discharge from the nose. Multiple episodes of mid-grade fever had also been reported. The surgeon had placed the patient on 500 mg of Augmentin (SmithKline Beecham Pharmaceuticals, Philadelphia, PA) for 10 days to control what could be a possible infection. The patient’s symptoms were a feeling of heaviness on the right side of the head with right maxillary sinus congestion. A computed tomography (CT) scan was ordered to evaluate the current bone graft. It showed bone graft material occupying approximately 80% of the volume of the right maxillary sinus with only the ceiling of the right maxillary sinus still aerated (Fig. 1).

Fig. 1. Computed tomography view of the maxillary right and left sinuses.

Computed tomography view of the maxillary right and left sinuses

The medial extent of the right maxillary bone graft was just below the ostium of the right maxillary sinus (Figs. 2, 3, and 4). There was also a mucosal thickening along the nasal side of the right maxillary ostium.

Fig. 2. Computed tomography view of the right maxillary sinus showing the current bone level.
Fig. 3. Computed tomography view of the right maxillary sinus showing the current bone level.
Fig. 4. Computed tomography view of the right maxillary sinus showing the current bone level.

Computed tomography view of the right maxillary sinus showing the current bone level

The left maxillary bone graft occupied approximately half of the volume of the left maxillary sinus, ending well below the left maxillary sinus ostium (Fig. 5). There was also an approximately 12-mm in diameter rounded and well-defined radiolucency within the right maxillary bone graft immediately distal to a preexisting right-side implant (Fig. 5). The radiologist reported that it was unascertainable whether this was simply a nonossified segment of the bone graft or whether there was periapical inflammatory disease adjacent to the implant. He also noted that if further radiographic study of this radiolucency was needed, a bone scan could be considered to determine if there was active inflammatory disease or simply a still nonossified region of the graft. After reviewing the results of the scan, the patient was referred to an otolaryngologist for evaluation and possible treatment.

Computed tomography of the maxillary sinuses showing the bone level in the left sinus and the radiolucency inside the right sinus bone mass

Computed tomography of the maxillary sinuses showing the bone level in the left sinus and the radiolucency inside the right sinus bone mass

The results of the consultation were as follows: “The patient received sinus grafting approximately one year ago. He continues to have maxillary sinus area discomfort. After multiple courses of antibiotics and conservative treatment, a CT scan has shown the right maxillary sinus to be almost 80% obliterated by packed bone. The concern has been expressed that his symptoms might be related to paranasal sinus disease related to the bony obstruction of the maxillary sinus ostium. Intranasal examination showed some mucosal edema bilaterally, but after the application of Neo-Synephrine (Sanofi Winthrop, New York, NY) and lidocaine, a full nasal endoscopy was performed. To my surprise, the patient had a patent maxillary antral opening. In fact, it is somewhat wider, most likely related to a nasal antral window enlargement performed at the time of his surgery.
The otolaryngologist reported he could see a mounding of nonmucosal covered bone in the maxillary sinus with no evidence of granulation tissue, purulence, or other abnormalities. The nasopharynx, hypopharynx, and larynx were negative. The CT scan indeed shows a radiolucency near the posterior aspect of the longstanding dental implant. Most likely, this represents chronic inflammation. A pseudoaneurysmal bone cyst may have occurred. The otolaryngologist highly recommended that this be addressed from a dental standpoint, stating that if it had resolved, and no inflammation was found, and symptoms persisted, then he would be happy to reevaluate the patient and consider an endoscopic approach to the right maxillary sinus; but at this point, he felt any manipulation could be damaging.”

Discussion - Conclusions - References.
The author’s impression is that the current complication is the result of excessive elevation of the schneiderian membrane during the bone grafting procedure. This usually results in a folded membrane superiorly positioned, which cannot be brought inferiorly to a lower position. This increased the dimension of the compartment to receive the bony graft material. As a result, the surgeon was forced to fill the entire area to the more superior level than was anticipated. The patient’s current symptoms are synonymous with the findings. The ideal treatment is to somehow approach the newly formed floor of the sinus and reduce the bone height to allow aeration of the sinus. This proposed procedure has never been attempted before; therefore, it will definitely need an otolaryngologist’s intervention. The current plan is to monitor the area for future surgical intervention. However, the patient decided not to pursue any further implant-related treatment and to have a maxillary partial denture fabricated for replacement of his missing teeth.

This complication of excessive augmentation of the maxillary sinus could have been prevented with gentle elevation and meticulous manipulation of the sinus floor membrane as described in the literature.3–7 Measurement of the desired bone height should be done from the CT scan or the panoramic film before the procedure. During the procedure, elevation of the membrane should also be measured using periodontal probe or a ruler to avoid an overfill. Elevation of the membrane is always attempted by separating the membrane from the bony walls of the sinus. The membrane is folded in a superior position; therefore, it cannot be unfolded and brought inferiorly. If this occurs, then the best way to handle this complication is to abort the procedure rather than overfilling the sinus.
Another attempt can be accomplished in several weeks in which the membrane will eventually relapse toward the floor of the sinus. Although the findings in this case are highly unusual and not previously documented, it is proposed that an experimental procedure should be attempted to reduce the height of the excessive bone mass in the maxillary sinus. The approach, the technique, and the necessary armamentarium should be investigated. An otolaryngologist is being called upon to investigate this situation and its solution.


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