Authors: Pascal Grün, Patrick Bandura, Benedikt Schneider, Anna Sophia Bandura, Florian Pfaffeneder-Mantai, Dritan Turhani
Categories: Case Report, Antral pseudocyst, Case report, Dental implant, Maxillary sinus augmentation, Radiographic feature change
Source: International Journal of Surgery Case Reports
Authors: Pascal Grün, Patrick Bandura, Benedikt Schneider, Anna Sophia Bandura, Florian Pfaffeneder-Mantai, Dritan Turhani
Maxillary sinus floor augmentation is acceptable and safe for bone augmentation prior to insertion of dental implants in atrophied maxillary bones. Anatomical variations and lesions of the maxillary sinus, including antral pseudocysts, are common radiological findings that can affect the outcomes of maxillary sinus augmentation. We show the changes in the radiological features of an antral pseudocyst that existed before maxillary sinus augmentation and 15 years after the insertion of dental implants.
The patient was a 69-year-old male with an unremarkable medical history. The initial orthopantomogram revealed a very large antral pseudocyst in the left maxillary sinus. After upper left second molar extraction and maxillary sinus augmentation, two dental implants were inserted in regions 26 and 27. The pseudocyst had changed radiologically 15 years later, but a biopsy showed no characteristic changes, and the dental implants showed no functional failures.
We present a case of an antral pseudocyst that was not removed before or during sinus floor augmentation. A debate is ongoing regarding whether antral pseudocysts affect maxillary sinus augmentation, and various strategies have been applied to prevent intraoperative and postoperative complications, including removal of pseudocysts 3–12 months before maxillary sinus augmentation, removal during maxillary sinus augmentation, and leaving them alone when the floor is raised.
The present case showed a preexisting antral pseudocyst at maxillary sinus floor augmentation and insertion of the implants, which changed radiologically 15 years later, but did not affect the function of the dental implants.
Maxillary sinus augmentation (MSA) is routinely performed with predictable results [1,2] and is an acceptable and safe treatment modality for bone augmentation to increase alveolar bone height and facilitate implant placement [3].
Although the long-term implant survival rate with lateral MSA is >90 %, it is a technique-sensitive procedure owing to complications that can occur during or after surgery [4].
Complications may compromise bone formation, possibly requiring a second surgery or, alternatively, abandoning implant treatment.
Anatomical variations and lesions of the maxillary sinus are common findings on cone-beam computed tomography (CBCT) scans of the maxilla prior to the placement of dental implants [5]. Therefore, careful CBCT examination is necessary to exclude lesions in the maxillary sinus, such as maxillary cysts.
Maxillary sinus cysts are a group of lesions with controversial nomenclature and pathogenesis.
Most researchers have classified maxillary sinus cysts into three true sinus mucoceles, retention cysts, and antral pseudocysts [6].
Antral pseudocyst (AP) is a sessile soft tissue elevation on the floor of the maxillary sinus caused by the accumulation of inflammatory exudates surrounded by loose connective tissue [7,8].
APs are a pathological condition that can affect MSA outcomes. The presence of APs can complicate surgical procedures by increasing the risk of membrane perforation and postoperative complications [9].
Maxillary antral cysts have a prevalence of 11.41 %, most of which are pseudocysts [10].
On orthopantomography (OPT), the radiological features of an AP present as a dome-shaped, faintly radiopaque lesion arising from the floor of the maxillary sinus [11,12]. The pathogenesis of AP remains unclear [13]. It could be related to an adjacent odontogenic infection, or a result of a recurrent upper respiratory tract infection [6].
The purpose of this case report was to show the change in the radiological features of an AP existing before MSA and 15 years after the insertion of dental implants. To the best of our knowledge, the course over such a long period has not been described in the literature.
We present this case report in accordance with SCARE 2020 criteria [14].
We present the case of a 69-year-old Caucasian male patient who was referred (in February 2023) to an oral and maxillofacial surgery clinic for extraction of a non-preservable upper left canine and insertion of an implant.
The patient's genetic profile was unremarkable. He had no significant psychological, family, or drug history, and was a nonsmoker.
A large cystic lesion in the maxillary sinus was diagnosed during the preoperative OPT in 2007.
In 2008, the upper left second molar was extracted, followed by MSA (Fig. 1A) using Bio-Oss® (Geistlich, Wolhusen, Switzerland) granules measuring 0.25–1 mm. In the same session, two implants were placed simultaneously in regions 26 and 27.Fig. 1A. OPT after extraction of the upper second molar, sinus augmentation and insertion of two implants (2008).B. OPT 15 years after sinus augmentation and insertion of the implants (2023).Fig. 1
Interestingly, changes in radiological features were diagnosed one year after MSA at the time of delivery of prosthetic care 15 years later, the cystic lesion showed larger and more radiopaque in the OPT (Fig. 1B). It was not possible to find out why the cystic lesion was not completely removed during extraction by the previous practitioner.
Subsequent computed tomography (CT), and CBCT in 2023 revealed sclerosis on the floor of the left maxillary sinus, with reference to the lateral wall, localized at the level of the two implants (Figs. 2A + B + 3A + B + C). Partial erosion of the bone structures between the two implants was also observed. There was a clasp-like cystic structure with a craniocaudal diameter of 2.6 cm originating from the sclerosis.Fig. 2A. CT frontal view 15 years after sinus augmentation and insertion of the implants (2023).B. CT transversal view 15 years after sinus augmentation and insertion of the implants (2023).Fig. 2Fig. 3A.–B. CBCT transversal views 15 years after sinus augmentation and insertion of the implants (2023).C. CBCT sagittal views 15 years after sinus augmentation and insertion of the implants (2023).D. CBCT frontal images after the osteotomy to create a window to expose the maxillary sinus (2023).Fig. 3
A CT revealed no structures suspicious of malignancy based on the slice images. Because the findings were typical of a sclerotic process, no further diagnostic measures were deemed necessary. Follow-up radiography was initially recommended annually to monitor the course of findings in the left maxillary sinus.
Nevertheless, the patient was advised in 2023 to have the cystic lesion completely removed using functional endoscopic sinus surgery (FESS) [15] which he refused. Only a small surgical biopsy was taken to clarify the histological assessment.
After the formation of a mucoperiosteal flap on the facial wall of the maxillary sinus, a completely inconspicuous bone was observed. Osteotomy was performed to create a window to expose the maxillary sinus (Figs. 3D and 4A).Fig. 4A. Mucoperiostal flap to expose the facial wall of the maxillary sinus (2023).B. Intraoperative view of the sinus showed a closed bony space with lined mucosal epithelium (2023).C.–D. The histopathological examination revealed small bone fragments, as well as fibrosed connective tissue fragments (2023).Fig. 4
Intraoperatively, a closed bony space with lined mucosal epithelium was observed (Fig. 4B). However, these findings were not resolved. Pathological findings could not be visualized; therefore, only a part of the mucosa was removed for histopathological examination.
The histopathological examination revealed small bone fragments, as well as fibrosed connective tissue fragments (Fig. 4C + D). There was no evidence of malignancy.
The patient was administered postoperative analgesics and antibiotics. After one week, the sutures were removed under non-irritant conditions.
Interestingly, despite radiological changes in the AP, the implants in regions 26 and 27 showed no functional failure 15 years after insertion.
There is an ongoing debate regarding whether APs affect MSA procedures, and various strategies have been used to prevent possible intraoperative and postoperative complications. Three strategies have been removal of pseudocysts 3–12 months prior to MSA [16], removal during MSA, and leaving them alone when performing the operation [17].
According to previous studies, the presence of an antral cystic lesion may be considered a contraindication for MSA, and cyst removal prior to the procedure is recommended [18].
The patient was referred to the current maxillofacial surgeon for extraction of the upper left canine. The patient was informed about the cystic lesion in the upper left sinus. It could not be clarified why the cystic lesion in the tooth extraction in 2007 or in the MSA in 2008 was not completely removed by the previous practitioner. The current practitioner clarified the case for both the patient and scientific purposes. However, he was not involved in the extraction of the tooth, the MSA, the implantology, or the prosthetic care. Nevertheless, the patient was advised in 2023 to have the cystic lesion completely removed using FESS, which he refused. Only a small surgical biopsy was taken to clarify differential diagnoses such as mucous retention cysts (primary mucoceles), odontogenic cysts, odontogenic keratocysts, or cystic ameloblastoma, which belong to the odontogenic tumors [19].
A study by Feng et al. reported that 31.7 % of patients with APs who underwent MSA experienced complications compared to only 7.4 % of patients without APs [20].
The most common postoperative complication is perforation of the maxillary sinus membrane.
In addition, during MSA, APs can burst and release their contents into the maxillary sinus, leading to infections and other complications. The presence of APs can delay the healing process because they can cause inflammation and interfere with the formation of new bone around the dental implant. Infected APs can cause inflammation, swelling, and pain. They are also highly vascular, and rupture during MSA can cause significant bleeding. The presence of APs increases the risk of sinusitis, which can lead to pain, pressure, and obstruction of the affected area. They may also compress the surrounding structures, including nerves, and cause sensory disturbances or numbness. Finally, APs can affect the stability of dental implants, leading to implant failure or revision.
In contrast, APs have recently been reported not to be a contraindication for MSA procedures when a lateral approach is used [21].
In some cases, APs may require alternative treatment options other than dental implants. For example, short dental implants have been widely used. These implants are designed to be shorter, which can be useful in cases where the bone height in the maxillary sinus is insufficient.
Some studies have reported a lower success rate in patients with APs, whereas others have found no significant difference in success rates between patients with and without APs. A retrospective study reported a lower implant survival rate in patients with APs than in those without AP (87.5 % vs. 94.6 %, P = 0.04) [22].
Notably, implant status is a key consideration during postoperative follow-up. However, since many patients refuse clinical management of asymptomatic pseudocysts, considerations regarding such pseudocysts should not be limited to preservation or surgical removal alone. Changes in pseudocyst size, location, and morphological characteristics after implantation should be closely monitored to guide subsequent treatment and facilitate risk assessment [13].
A systematic review concluded that the available evidence is insufficient to support either approach and that the management of APs should be individualized based on the size, location, and clinical presentation of the cysts [23].
The literature shows that larger APs (> 10 mm) were associated with a higher risk of membrane perforation during MSA [7].
In the present case, no adverse effects were observed on the implant insertion, the healing, or the postoperative survival phases of the implants. Pre-implant therapy could have resulted in undesirable complications such as membrane perforation, but would definitely have led to an extension of the treatment strategy.
In addition, AP showed radiological changes in size and radiopacity; however, the biopsy did not show any characteristic changes, and the dental implants did not show any functional failures.
APs are frequently detected using radiographic imaging and can significantly influence the outcomes of MSA procedures in implant dentistry. The presence of APs can increase the risk of complications such as membrane perforation and may lower the success rates of MSA. However, the effect of APs on MSA remains controversial, with conflicting results reported in the literature. The management of APs associated with MSA is also controversial, with different authors advocating different approaches.
Therefore, it is important for clinicians to carefully evaluate the presence and characteristics of APs on radiographic imaging and consider their potential impact on MSA. Clinicians should also consider individualizing the management of APs based on the size, location, and clinical presentation of the cysts.
In the present case, we showed that an AP was present before MSA and insertion of the dental implants. However, 15 years later, although it had changed radiologically, it still had no effect on the function of the dental implants.
Further research is needed to better understand the impact of APs on MSA and develop evidence-based guidelines for their management.
The patient received a thorough explanation of this report gave her oral and written informed consent to be included in this report as well as for publication of these case, anonymous data, and pictures. A copy of the written consent is available for review by the Editor-in-Chief of this journal on request.
Not commissioned, externally peer reviewed.
This study was approved by the Committee for Integrity and Ethics in Research of Danube Private University with approval number (DPU-EK/034).
Not applicable.
Pascal Grün and Patrick Bandura: study concept and design, writing the paper. Pascal Grün, Benedikt Schneider, Anna Sophia Bandura and Florian Pfaffeneder-Mantai: data collection, analysis and discussion of data. Dritan Turhani: final approval of the version to be published. All authors read and approved the final manuscript.
Dritan Turhani.
Not applicable.
Not applicable.