Perforated schneiderian membrane repair during sinus augmentation in conjunction with immediate implant placement

Abstract

Dental implant associated rehabilitation of the posterior maxilla poses unique challenge owing to the presence of pneumatized sinuses and atrophied alveolar bone. Sinus augmentation procedure to manage expanded sinuses frequently results in membrane tear resulting in unfavorable stabilization of the graft and associated bone regeneration. Simultaneous implant placement during sinus augmentation procedures frequently requires a minimal alveolar bone height, which when not present forces clinician to defer implant placement resulting in extended treatment duration and multiple surgical appointments. The present case report is about a piezosurgery assisted lateral wall osteotomy approach for sinus augmentation associated with membrane repair with simultaneous implant placement in the posterior maxilla.

Rehabilitation of the upper posterior maxilla with implants has shown a high success in the presence of normal bone volume and density.[1,2,3] Prolonged edentulism of posterior maxilla is frequently characterized by ridge atrophy, pneumatization of the sinuses, low bone density and excessive occlusal loads of the dental arch, thus resulting in insufficient residual bone and complicating implant placement.[4,5]

The most successful surgical technique to access the maxillary sinus is performed by the lateral access window (modified Caldwell-Luc technique)[6,7,8,9] or a less-invasive approach through the crest of the alveolar ridge utilizing osteotomies or a combination of osteotomies and e drill.

External sinus lifting procedure enables one to place implants with a vertical height gain of up to 12 mm.[10]

Perforation of the Schneiderian membrane during external sinus augmentation is a well-documented phenomenon and is most likely to happen at sharp angle and ridge line, septa, and spines.[11] The formation of mucocele, chronic sinusitis, oroantral fistula, loss of graft material and implant nonosseointegration are other complications reported in the literature associated with membrane perforation.[12,13,14] Perforation of the maxillary sinus membrane were classified by many researchers and have been concluded that they were commonly treatable with the use of collagen membranes.

The present case report is about an external sinus augmentation utilizing piezosurgical techniques associated with membrane repair with simultaneous implant placement in the posterior maxilla.

Case Report

A 41-year-old systemically healthy female patient presented with the chief complaint of missing teeth in the left upper posterior region for past 7 months. Patient gave a dental history of implant placement in relation to 24, 44, and 47 1 year back. Patient had undergone endodontic therapy in relation to 11, 21, 15, 16, and 17 with postendodontic restoration. A tooth supported fixed partially denture in relation to 34.35 and 36 and an implant supported fixed partial denture in relation to 44, 45, 46, and 47 region. Digital orthopantomogram (OPG) revealed a residual bone height of <2 mm in relation to 26.27 and around 4 mm in 25 region with a pneumatized sinus and horizontal bone loss on the mesial aspect of implant in 24 region.

Treatment plan of lateral wall osteotomy approach for sinus augmentation associated with simultaneous implant placement in 25, 26, and 27 region was decided upon. In spite of the literature data insisting on the minimum of 4 mm alveolar bone height for simultaneous implant placement during sinus augmentation procedures the decision of simultaneous implant placement was still considered due to the fact that implants placed creates a tenting effect resulting in excellent space maintenance for optimal regeneration.[15] Moreover such approach greatly reduces over all treatment duration and multiple surgical appointments. Considering the bone loss in 24 region a laser debridement was also planned followed by placement of splinted metal ceramic crowns involving 4 implants including implant in 24 region.

Patient was informed of the therapeutic alternatives to the sinus lift. The risk of perforating the sinus membrane and the possible complications was also explained and written informed consent was obtained.

Surgical Procedure

The surgical site was anaesthetized by local infiltration with 2% lignocaine hydrochloride (1:200000 adrenalin). Two vertical releasing incisions one on the distal line angle of 24 and the other on the distal most aspect of the ridge with a para–crestal incision joining both these vertical releasing incisions was given [Figure 1a and 1b]. A mucoperiosteal flap was elevated exposing the lateral wall of the maxillary sinus [Figure 1c].

Figure 1.

(a) Preoperative intraoral view, (b) Placement of para – crestal and vertical releasing incisions, (c) Flap elevated exposing the lateral bony wall, (d) Preparation of bony window

Piezo surgery assisted sinus augmentation

Using a round end piezo tip a bony window was prepared [Figure 1d] and was infractured, followed by the elevation of the schneiderian membrane using the sinus elevation tips. During sinus membrane elevation a class IIA type perforation[16] occurred [Figure 2a], following complete elevation of the sinus membrane an implant osteotomy was performed in 25, 26 and 27 region [Figure 2b].

Figure 2.

(a) Infracture of bony window, perforation of sinus membrane encountered during membrane elevation, (b) Implant osteotomy sites prepared in 25, 26 and 27, (c) Type I collagen membrane (BioMend Extend^®) placed to repair the perforated sinus membrane, (d) Sinus cavity partially packed with deproteinized bovine bone (Bio-oss^®)

Before placing the implants the perforation of the schneiderian membrane was managed by adapting a contoured guided bone regeneration (GBR) type I collagen membrane (BioMend Extend^® - Zimmer dental, 1900 Aston Avenue, Carlsbad, CA 92008-7308 USA, lot no.: 1094148) in such a way that the perforated membrane was completely shielded from the elevated sinus cavity [Figure 2c].

The sinus space was partially packed with deproteinized bovine bone (Bio-oss^® - Geistlich biomaterials batch no. 080307) hydrated with blood [Figure 2d] followed by the placement of three wide platform tapered self-threaded titanium implants (Hi-Tec Life Care Israel for Life care devices private limited, 202 Jesia building, Jame Jamshed road, Dadar east, Mumbai - 14 – Lot No : 030610,08097,16108) [Figure 3a]. The residual spaces around the implants were further packed with Bio-oss^® graft [Figure 3b]. A type 1 collagen GBR membrane (BioMend Extend^®) was contoured and adapted to cover the bony window and tucked under the palatal flap [Figure 3c]. The reflected flap was approximated with 4-0 vicryl (Ethicon, Inc., Johnson and Johnson, Somerville, NJ, USA) using simple interrupted sutures [Figure 3d].

Figure 3.

(a) Implant placed in prepared osteotomy sites, (b) Residual sinus cavity filled with Bio– oss^®, (c) Placement of collagen membrane (Bio mend Extend^®) to cover the implants and access window, (d) Flap approximated using 4-0 vicryl suture material

The patient was placed on amoxicillin/clavulinic acid 625 mgs 2 tablets/day for 5 days, ibuprofen/paracetomol 3 tablets/day for 5 days and Fexofenadine chloride 60 mg plus pseudoephedrine chloride 120 mg 1 tablet every 12 h, for 7 days (decongestant). Patient was advised to rinse with chlorhexidine gluconate 0.2% mouth wash twice daily for the following 4 weeks.

Patient was reviewed the next day and after 4 weeks with the postsurgical healing being uneventful at this junction laser debridement for the aligning implant in 24 region was performed. Patient was placed on periodic recall every 2 months until the 8 month during which a digital OPG and computed tomography was taken. The radiographs showed the position of implant and dense bone fill in the sinus cavity [Figure 4a–d].

Figure 4.

(a) Fully functional metal ceramic prosthesis, (b) Computed tomography shows the position of implants, (c) Preoperative radiograph shows ridge deficiency, (d) 8 months postoperative radiograph shows the augmented site with implants

During the second stage the implant recovery was done with laser and healing caps were placed and left in place for 4 weeks. 4 weeks following healing cap placement the prosthetic abutment was screwed in with a 40 Ncm torque. The metal ceramic crown on 24 implant was retrieved and a silicone impression was taken involving implant abutments in 24, 25, 26 and 27 region. Following metal and ceramic try in, a metal ceramic prosthesis (5 units considering the mesiodistal space available) was cemented and patient was reviewed after a week during which the patient was comfortable and the prosthesis was fully functional.

Discussion

Maxillary sinus augmentation is commonly undertaken to enhance otherwise inadequate bone dimension for placement of dental implants in the posterior maxilla. The most important factor is to keep the schneiderian membrane intact during sinus augmentation so that once lifted, it can become the recipient site for the bone graft and it stabilizes the graft during the healing period, constituting an important barrier for the protection and defense of the sinus cavity. Its integrity is essential to maintain the health of normal function of the sinus. Complications reported during sinus augmentation surgery are excessive bleeding during surgery, implant migration, hematoma, injury of the infraorbital neurovascular bundle and adjacent tooth sensitivity of which the most significant complication is membrane perforation which has a negative impact on graft remodeling.[17] Though piezo surgical techniques are frequently employed in sinus augmentation procedures for atraumatic osteotomy and to minimize membrane perforation, incidence of schneiderian membrane tear is not uncommon.[18] Various techniques used for the treatment of membrane tear are circumelevation technique, Loma Linda Pouch technique and the perforated membrane can be managed by using tissue fibrin glue, suturing or by covering them with a resorbable barrier membrane in case of small perforation (<5 mm), if the perforation is >5 mm larger barrier membranes, lamellar bone plates or suturing either alone or combination with fibrin glue can be advocated. In the present case report the type of perforation was a class II A and the size of perforation was larger than 3 mm so it was managed using a resorbable membrane.[16]

Various graft materials such as autogenous, allogenous, xenograft and alloplastic materials have improved the results of sinus augmentation techniques and made them more predictable.[19,20,21] Deproteinized bovine bone (Bio-oss^®) as used in the present study have shown to be favorable due to its optimal resorption period, commercial availability, higher survival rate of implants and excellent handling characteristics.[22,23,24]

Simultaneous implant placement during external sinus augmentation requires a minimum of 4 mm of remaining alveolar bone for minimal initial stability and preventing implant migration during regeneration.[13,14,25,26,27,28] In the present case report, implants were placed in the sites with the residual alveolar bone of lesser than 2 mm considering various advantages such as fewer surgical procedures, reduced overall treatment duration, less morbidity, less financial expense and less patient anxiety. Added advantage of the implant placed in the residual alveolar bone of lesser than 2 mm is the tenting effect of the implant on the repaired sinus membrane acting as a space maintainer.

In the present case report, implants were placed simultaneously during sinus augmentation procedure in spite of <2 mm of bone height available in 26 and 27 region and during the sinus augmentation membrane perforation occurred, which was carefully managed, postoperative healing showed optimal bone fill in the sinus region and successful ossiointegration in the implant sites. The final prosthesis was esthetic as well as functional.

Conclusion

External sinus augmentation with simultaneous implant placement is a viable option even in areas with residual bone height of <4 mm as this approach reduces overall treatment duration and the stress of multiple surgical procedures for the patients.