This study presents the case of a patient who required antrostomy under general anesthesia to treat a sinus lift complication. The patient was a 43-year-old woman with no systemic abnormalities who underwent maxillary sinus lift surgery associated with mineralized bovine bone graft. The Schneiderian membrane was perforated during the procedure, and the rupture was treated with collagen membranes to close the wound and contain the biomaterial, preventing its dispersion. The patient developed a maxillary sinus infection 7 days after surgery. This infection was initially treated with 875 mg amoxicillin combined with 125 mg clavulanic acid. Although the initial infection did not worsen, the patient developed maxillary sinusitis. Thirty days after the onset of the initial infection, the patient underwent an intraoral surgery under local anesthesia to remove the biomaterial and clean the sinus cavity. Despite this procedure, maxillary ostial patency was still compromised, and antrostomy was performed endoscopically in a hospital setting under general anesthesia. This procedure resolved the sinus infection. Then, 12 months after hospitalization, the patient was treated with another sinus graft surgery without postoperative complications. The treatment of sinus infections caused by the graft surgery may require early and active intervention with antibiotics, graft removal, and antrostomy to prevent major complications.

A common complication during the maxillary sinus floor augmentation surgery is perforating the Schneiderian membrane. The literature reports an intraoperative incidence of Schneiderian membrane perforation between 10% and 60%.1,2  Many risk factors contribute to the occurrence of this perforation, including the presence of septa, membrane thickness, pathology involving the sinuses, angle of lateral and medial walls of the maxillary sinus, gingival phenotype, bone irregularities, excessive amount of bone substitute, surgeon inexperience, and technical errors.35 

Perforating the Schneiderian membrane may lead to postoperative complications such as bacterial infection, edema, pain, bleeding, wound dehiscence, loss of bone substitute, changes in sinus physiology, and increased risk of implant loss.5 

The incidence of postoperative infection lies between 2% and 5.6% of cases. These infections might originate from previous infections in the maxillary sinus or bone graft, the latter occurring the most.68  Although less frequent, sinus infections might have more serious consequences such as sinusitis, which results from the interconnections of facial sinuses.9  Even with low incidence, maxillary sinus infections might occur and compromise sinus lift procedures. Cases of graft infection might require complete graft removal associated with antibiotic therapy5  to prevent more serious consequences for patients. Antrostomy is an option for removing contaminated material and indicated in more complex cases to enlarge the ostium.10 

According to Moreno et al,11  complications may require additional surgery, hospitalization, and long recovery periods, impacting the quality of life and potentially leading to death. These complications may also compromise the outcome and viability of the graft and consequently compromise subsequent implant installations.

This study is a rare case of severe sinus infection after complications of maxillary sinus augmentation that were treated with antrostomy in a hospital.

A 43-year-old female patient with no systemic diseases or conditions attended a clinic complaining of pain and mobility in the first maxillary left molar. The clinical examination showed gingival inflammation and purulent drainage in the first maxillary left molar. The computed tomography (CT) scan showed evidence of endodontic treatment performed in the referred tooth, as well as bone loss and roots of the teeth close to the maxillary sinus. The treatment plan included a maxillary sinus floor augmentation and simultaneous implant placements (Figure 1).

Figures 1 and 2.

Figure 1. Initial panoramic and sagittal CT scans.

Figure 2. Immediate postoperative panoramic and sagittal CT scans showing biomaterial surrounded by the collagen membrane after the perforation. The left maxillary sinus is opaque due to the presence of blood (hemosinus).

Figures 1 and 2.

Figure 1. Initial panoramic and sagittal CT scans.

Figure 2. Immediate postoperative panoramic and sagittal CT scans showing biomaterial surrounded by the collagen membrane after the perforation. The left maxillary sinus is opaque due to the presence of blood (hemosinus).

Close modal

The Schneiderian membrane was perforated during the creation of the bone window. The complication was aggravated by the detachment and final elevation processes, resulting in a perforation of approximately 1.5 cm in length. The perforation was treated by placing 3 absorbable collagen membranes (Collagen Tape) 1 cm beyond the borders of the osteotomy. The mineralized bovine bone graft material (Bio Oss, Geistlich Pharma AB) was inserted in the cavity established by the collagen membrane. One membrane was placed over the maxillary sinus access window.

The patient was prescribed 500 mg amoxicillin 3 times a day for 7 days, 600 mg ibuprofen 3 times a day for 5 days, and a mouthwash (0.12% chlorhexidine digluconate) 3 times a day for 7 days.

The immediate postoperative CT scan revealed grafting material in the sinus lift, a gap occupied by the collagen membrane separating the sinus cavity from the grafting material, and the presence of blood inside the left maxillary sinus (hemosinus) (Figure 2).

Ten days after surgery, the patient called the clinic reporting pain, fever, halitosis, rhinorrhea, nasal obstruction, cellulitis on the left side of the face, and gingival hyperemia at the base of the groove of tooth number 26 (Figure 3a and b). The CT scan revealed an opaque maxillary sinus and loose hyperdense biomaterial inside the cavity. After an evaluation, the patient was prescribed 875 mg amoxicillin combined with 125 mg clavulanic acid 3 times a day for 7 days, as well as 400 mg metronidazole 4 times a day for 5 days (Figure 4).

Figure 3.

(a) Extraoral cellulitis 10 days after sinus lift surgery. (b) Gingival hyperemia at the base of the groove of tooth number 26.

Figure 3.

(a) Extraoral cellulitis 10 days after sinus lift surgery. (b) Gingival hyperemia at the base of the groove of tooth number 26.

Close modal
Figures 4 and 5.

Figure 4. Follow-up CT scan 10 days after sinus lift surgery.

Figure 5. Follow-up CT scan 10 days after surgery revealing an opaque left sinus cavity and loose biomaterial.

Figures 4 and 5.

Figure 4. Follow-up CT scan 10 days after sinus lift surgery.

Figure 5. Follow-up CT scan 10 days after surgery revealing an opaque left sinus cavity and loose biomaterial.

Close modal

Ten days after the previous prescription, the patient was reassessed and showed no relief from the signs or symptoms of infection. A clinical examination showed a fistula in the region of the access flap of the sinus lift surgery near the alveolar ridge and the CT scan showed an even more widely spread hyperdense biomaterial within the sinus cavity (Figure 5).

Thirty days after the initial graft surgery, a second surgery was performed to remove the purulent content and remaining biomaterial using the Caldwell-Luc approach, followed by sinus irrigation with saline solution and closure of the oronasal fistula (Figure 6). The patient was prescribed 750 mg levofloxacin once a day for 7 days, as well as a 0.9% sodium chloride nasal spray. The immediate postoperative CT scan revealed a lack of biomaterial and increased thickness of the Schneiderian membrane.

Figure 6.

CT scan immediately after the removal of the biomaterial, showing an increase of the Schneiderian membrane (30 days after the original sinus lift procedure).

Figure 6.

CT scan immediately after the removal of the biomaterial, showing an increase of the Schneiderian membrane (30 days after the original sinus lift procedure).

Close modal

However, 2 days after the second surgery, the patient presented no symptom relief, and there were still signs of infection (Figure 7a–c). Thus, 32 days after the initial graft surgery that caused the complications, the patient was sent to an otolaryngologist, who decided to perform an endoscopic antrostomy under general anesthesia and maintain antibiotic coverage with levofloxacin for 5 days (Figure 5d). After this procedure, the patient had follow-up CT scans yearly, all of which showed a resolution of the infection (Figure 8).

Figure 7.

(a) Clinical presentation 2 days after removing the biomaterial. (b) Axial CT scan showing an opaque left sinus. (c) Sagittal CT scan showing purulent content in the ethmoidal sinuses. (d) Endoscopy to open the maxillary sinus ostium.

Figure 7.

(a) Clinical presentation 2 days after removing the biomaterial. (b) Axial CT scan showing an opaque left sinus. (c) Sagittal CT scan showing purulent content in the ethmoidal sinuses. (d) Endoscopy to open the maxillary sinus ostium.

Close modal
Figure 8.

CT scan performed 12 months after antrostomy, showing a lack of opacity in the left sinus cavity and a membrane of normal thickness.

Figure 8.

CT scan performed 12 months after antrostomy, showing a lack of opacity in the left sinus cavity and a membrane of normal thickness.

Close modal

There are few reports in the literature on sinus graft surgery complications that required hospitalization. Although rare, most of these reports involve infections (sinusitis or graft infection) caused by the perforation of the Schneiderian membrane.11 

This type of perforation is common and both membrane thickness and the presence of septa increase its likelihood.5,12  The treatment for Schneiderian membrane perforation depends on the extent of the perforation and requires closing the oronasal communication using collagen sponges, absorbable sutures, allograft tissue, increased membrane elevation to create a fold that covers the perforation, fixation of bone blocks, or placement of a resorbable collagen membrane, the latter being the most common option.1,4,1315 

In the case hereby reported, the perforation was large (1.5 cm long), and 3 membranes were placed in an attempt to recreate the cavity previously provided by the Schneiderian membrane. However, 10 days after the surgery, the patient returned with a sinus infection. The immediate removal of the infected grafted material, which would have been the appropriate treatment, was not performed because of an incorrect decision-making process.

The success rate of the perforation treatment is high3,4  when using collagen membranes, although infections such as sinusitis may occur and must be treated as quickly as possible through the combined use of antibiotic therapy and removal of the contaminated graft material. When biomaterial is found inside the maxillary sinus, it must be immediately removed intraorally. These steps were not followed in the present case. Consequently, the infection completely occluded the ostial patency and prevented physiologic sinus drainage.

Ostial patency is the most important factor in the pathogenesis of sinus infections. The perforation of the Schneiderian membrane and the migration of a foreign body into the maxillary sinus may induce maxillary sinusitis. However, maxillary sinusitis may also occur in procedures in which the membrane remains intact. The crucial factor in the development of maxillary sinusitis is not membrane integrity but the extent of maxillary ostial patency.20  The maxillary sinus ostium drains into the middle meatus and has an average size of 2.5 mm. When its size decreases because of an infection, the result is often a complete ostial obstruction. This obstruction results in secretion buildup, a pH reduction, and decreased oxygen within the sinuses. These changes allow bacterial propagation, resulting in the release of protease from leukocytes, which in turn causes the inflammation of the mucosa and changes to the mucosal epithelium.

Antibiotics must be administered in combination with immediate surgical intervention when postoperative infections are diagnosed.14,21  Most of these infections (70%) are caused by Streptococcus pneumoniae and Haemophilus influenzae. A small but significant percentage of these acute infections (6%–10%) are caused by anaerobic bacteria, namely Peptostreptococcus, Bacteroides, and Fusobacterium species. Moraxella catarrhalis causes approximately 4% of these infections and often results in a substantial increase in β-lactamase production.

The combination of amoxicillin and metronidazole is the ideal therapy of choice when these microorganisms are present in low numbers. There are also literature reports on the use of amoxicillin in combination with clavulanic acid, as well as quinolone antibiotics such as levofloxacin and gatifloxacin.3,11,22  A study reported that 16 of 20 patients with sinusitis receiving antibiotic coverage (ceftriaxone) for 7–10 days healed completely after surgery and sinus health was reestablished.15 

In cases of ostial obstruction caused by edema or mucosa, the area must be maintained clean to prevent bacterial buildup from ciliary dysfunction and the accumulation of secretions. Nasal decongestants and irrigation with saline solutions are required in these cases.

In some cases, the intervention by an otolaryngologist is essential for completely removing the material infected, which is performed under general anesthesia, and antrostomy is performed endoscopically. The goal is to remove the contaminated material from within the sinus cavity and clear the ostium, allowing for proper drainage. This procedure is performed by the otolaryngologist and complements the additional procedure performed by the dental surgeon, who typically removes the contaminated material not eliminated by the endoscope and closes any oroantral communications.

The literature reports complications such as orbital, intercranial, and bone infections.10  The study by Raghoebar et al,23  which followed up patients for 12–124 months after sinus bone graft procedures, found symptoms of acute sinusitis in 3 patients. Two other patients developed purulent sinusitis, 1 of whom had not experienced Schneiderian membrane perforation. In this case, the patient underwent an antrostomy of the middle meatus to improve drainage. The other patient experienced membrane perforation during the sinus lift procedure and underwent a functional endoscopy.

Early diagnosis and an adequate treatment plan provide the safest treatment for maxillary sinusitis caused by grafts during maxillary sinus floor augmentation. Preventive measures may also be effective for these complications.24,25  Authors in the literature have presented minimally invasive techniques to resolve these issues. For instance, Kunihiro et al20  report the use of endoscopic antrostomy during sinus lift surgery to prevent sinusitis. The authors treated approximately 100 patients, and there were no cases of postoperative sinusitis. These same authors advocate the performance of sinus irrigation with nasal decongestants 2–6 months before the procedures.20 

Sinus infections from sinus graft surgeries require early and active treatment involving antibiotics, graft removal surgery, and, when necessary, antrostomy, to prevent further or more serious complications.

Abbreviation

Abbreviation
CT:

computed tomography

The authors declare no conflicts of interest.

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