Migrated Maxillary Implant Removed via Semilunar Hiatus by Transnasal Endoscope

Abstract

Endoscopic surgery via nasal approach to remove the implant body from the semilunar hiatus is presented with the images of the computed tomography and the intraoperative endoscopic findings.

A transnasal endoscopic operation was carried out and presented the operative images to remove a maxillary implant from the semilunar hiatus. In rare cases, the body of a dental implant may migrate into the maxillary sinus. In this study, we report the case of a 54-year-old woman who consulted our oral surgery clinic regarding an abnormal feeling in the right maxilla and nasal pus discharge. Anamnesis and extraoral findings suggested right maxillary sinusitis. Panoramic radiographies, including those brought in by the patient, and computed tomography (CT) revealed the presence of a dental implant in the superior-internal region of the right maxillary sinus.

Transnasal endoscopic surgery was proposed to enable the removal of the maxillary migrated implant body from the semilunar hiatus.

Case Description

A 54-year-old woman came to our oral surgery clinic with an abnormal feeling in the right cheek and pus discharge from the right nostril as chief complaints. These were often accompanied by headache. Panoramic radiographs brought in by the patient showed maxillary and mandibular implant dentures (implant manufacturer unknown) that had been removed 3 years before because of inadequate fit. She complained of an intermittent abnormal feeling in the right cheek and headache. The implant location was estimated at the superior-internal region of the right maxillary sinus, with a suspected orientation perpendicular to the sagittal plane on the image of CT (Fig. 1). She was diagnosed with right maxillary sinusitis resulting from the migration of an implant body and admitted to the university hospital for treatment. An endoscopic operation using the nasal approach was carried out under general anesthesia. The endoscopic equipment (OLYMPUS, Japan) used in this procedure was borrowed from our ear-nose-throat department of Nagasaki University. The operation required 50 minutes with minimal bleeding.

Fig. 1.: Coronal (A, B) and sagittal (C, D) images from a computer tomography (CT) of the patient. The migrated implant body (arrow) was located at the posterior region within the right maxillary sinus, in a perpendicular orientation against the sagittal plane. The image indicated the possibility of removal by nasal approach, because one end of the implant was situated near the semilunar hiatus.

A rigid endoscope of 4 mm in diameter equipped with a digital video unit and optical viewing angles of 0 and 70 degree was used to visualize the middle nasal meatus. Careful exploration revealed the middle nasal meatus and inferior concha and recognized the semilunar hiatus (Fig. 2, A and B). One end of the implant body was seen at the posterior portion of the middle nasal meatus and removed from the maxillary sinus with a forceps (Fig. 2, C and D). As part of the treatment for sinusitis, part of the tissue membrane around the semilunar hiatus was extirpated and the passage was enlarged with a backbiter. The operation was finalized after gauze packing for homeostasis (Fig. 2, E and F).

Fig. 2.: Endoscopic findings of the operation. A, Pus discharged from the posterior region at the middle nasal meatus. B, Mucous membrane lining the semilunar hiatus covered by pus. C, One end of the implant body was seen at the upper portion of the middle nasal meatus. D, The implant body was gasped with a forceps and removed from the maxillary sinus. E, Mucous membrane of the maxillary sinus seen through the enlarged semilunar hiatus. F, Gauze packed at the enlarged semilunar hiatus for hemostasis. DP, discharged pus; EB, ethmoid bullae; ESH, enlarged semilunar hiatus; F, forceps; G, gauze; IB, implant body; INF, inferior nasal concha; MNC, middle nasal concha; NS, nasal septum.

The implant body looked like a flat metallic board with a tapered section on one end and a round hole on the other end (Fig. 3, A). Quantitative x-ray microanalysis detected a peak composition of titanium (Kevex 7000 x-ray microanalyzer and H-800 scanning and transmission electron microscope) (Fig. 3, B). Hematoxylin and eosin-stained sample of the specimen around the semilunar hiatus showed ciliated columnar epithelium accompanied with hypertrophied inflammation underneath. Lymphocyte invasion, plasma cell, and follicular lymph node were also seen (Fig. 3, C). Conventional antibiotic and anti-inflammatory therapy were prescribed.

Fig. 3.: A, Removed implant body (↑). This implant of an unknown manufacturer was shaped like a tapered board with a hole. B, Quantitative analysis of the implant body detected a peak in the titanium range by x-ray microanalysis (Kevex 7000 and H-800 scanning and transmission electron microscope). C, The collected soft tissue specimen stained by hematoxylin and eosin showed ciliated columnar epithelium accompanied by hypertrophied inflammation underneath. Invaded lymphocyte, plasma cell, and follicular lymph node were also seen.

The patient was discharged from the hospital 1 week after the operation and did not complain of any other abnormality thereafter.

Discussion

Although not a common phenomenon, maxillary dental implants may migrate into the maxillary sinus.^1,2 The posterior maxilla frequently has inadequate quality and quantity of bone, and the contiguous maxillary sinus often provides poor recipient sites for endosseous implants.³ Generally, dental implants in the maxilla are of relatively higher risk of failure because of the low density and poor quality of bone for osseointegration.⁴

There is evidence that contact between the maxillary sinus and implants may produce complications. Local infection of tissue around the implant is the most frequent adverse effect and may be associated with extensive resorption of the surrounding bone.² For this reason, implants placed very close to the maxillary sinus may offer a route for infection from the oral cavity to the sinus. Thus, sinusitis can readily result from an underlying condition of peri-implantitis. Recently, a drill device and method have been developed for the safe installation of an implant body at the posterior maxillary region.⁵

Migration of the dental implant into the paranasal sinuses or complicated maxillary sinusitis has been reported.⁶ Specific procedures have been indicated for the treatment of migrated implants, although the indications may vary depending on the symptoms in the maxillary sinus. For instance, the sinus wall opened under local anesthesia^1,7 or Caldwell-Luc procedure³ reported endoscopic extraction of a metallic foreign body from the maxillary sinus. Implant bodies have been removed intraorally through the implant preparation site. On the other hand, if the symptoms are very mild or absent, the case may merely be followed by regular x-ray monitoring observations and antibiotic treatment for the occasional symptom.²

The modern endoscopic optical system has made possible the examination of almost all cavities of the human body.⁸ The current techniques and adjunctive intraoperative technologies have allowed for more precise and safer surgical dissection. Some surgical applications now include routine endoscopic management.⁹ Endoscopic surgery has also been introduced in the field of oral surgery, for instance, to remove the mucus retention cyst of the maxillary sinus,⁸ to diagnose orbital floor fracture,¹⁰ and to aid in the complete separation of bone and soft tissue in orthognathic surgery.¹¹ Removal of cysts from the maxillary sinus has involved the Caldwell-Luc procedure. However, with the aid of an endoscope, a much smaller opening is possible. In some cases, it is difficult to diagnose orbital floor fracture because of swelling or poor radiographic imaging. An endoscope may be introduced through a smaller hole into the maxillary sinus for inspection. Furthermore, the endoscope can be used in orthognathic surgery or in the case of transoral treatment of displaced bilateral condylar mandible fracture,¹² because it enables the visualization of minute or delicate structures, such as nerves and blood vessels, within a complex surgical field.

The endoscope is particularly useful for the visualization of objects out of direct visual access through the use of optical viewing angles.¹² Endoscopic transnasal operation for the removal of dental implants from the maxillary sinus as described here offered several advantages over more conventional procedures. Advantages include reduced surgical time, less trauma, and bleeding, which often bring about a shorter time for patient recovery. However, the endoscopic nasal approach may not be feasible if the location of the implant body is not within the reach of a surgical forceps. Therefore, careful radiographic and CT evaluation is important before attempting this procedure.

Conclusion

A transnasal endoscopic operation was performed to remove the maxillary implant from the semilunar hiatus. X-ray microanalysis detected the peak of titanium from the implant body.