|Year : 2020 | Volume
| Issue : 2 | Page : 103-109
Sinus augmentation in atrophic maxilla: Lateral window approach
Tejal Mavinkurve1, Prasad Bhange2
1 BDS(MUM), Fellowship In Implantology (MUHS), Mumbai, Maharashtra, India
2 MDS Oral Surgery, Associate Professor Additional Department Of Dentistry, KEM Hospital, Mumbai, India
|Date of Submission||24-Aug-2020|
|Date of Acceptance||12-Oct-2020|
|Date of Web Publication||18-Dec-2020|
Dr. Tejal Mavinkurve
Siddhivinayak Dental clinic, Gorai sector 1, Borivali west, Mumbai-400 092, Maharashtra
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Rehabilitation of edentulous posterior maxillary regions by means of implant placement often poses challenging situations due to inadequate alveolar ridge height and poor bone quality. Since resorption of posterior residual ridge is caused by sinus pneumatization or traumatic extractions, maxillary sinus floor elevation (SFE) and bone augmentation with graft materials remains the method of choice. This scientific, evidence-based, preprosthetic procedure is a corrective technique available for almost two decades in such surgically compromised cases. In this article, we will discuss and review instrumentation by lateral window approach for SFE in conjunction with bone augmentation for delayed implant placement postgraft maturation in the healing period.
Keywords: Bone graft materials, direct lateral window, implants, maxillary sinus floor elevation
|How to cite this article:|
Mavinkurve T, Bhange P. Sinus augmentation in atrophic maxilla: Lateral window approach. J Dent Implant 2020;10:103-9
| Introduction|| |
Sinus floor elevation (SFE) with bone augmentation for delayed implant placement in atrophic, edentulous posterior maxillae is a time tested, scientific evidence based and increasingly popular procedure. In 1970s, Hilt Tatum first described transalveolar SFE, also referred to as subantral augmentation, which was later modified by Boyne and James in 1980. Later, numerous articles showed that when >5 mm of residual alveolar bone is available, simultaneous implant placement with adequate primary stability is achievable. However, when <5 mm of residual alveolar bone height is available in surgically, compromised cases, a delayed two-stage approach is recommended for predictable, successful outcome.,
- Lateral window approach for sinus augmentation using drills, curettes and bone graft material to compensate for inadequate vertical bony dimension of the sinus chamber in the lateral maxilla
- Delayed implant placement with definitive prosthesis.
| Case Report|| |
A 55-year-old female patient visited our clinic with a chief complaint of missing teeth in her upper, right jaw in the back region requesting replacement of missing teeth.
The patient had a medical history of controlled Hypertension and diabetes. Intraoral examination revealed dental history of a 5-year old porcelain-fused-to-metal fixed partial denture in the left, posterior maxilla with posterior, bilateral mandibular edentulism.
To aid preoperative treatment planning, the patient had to undergo thorough medical and dental examination to determine the feasibility of sinus augmentation therapy and implant rehabilitation. Being a long-standing diabetic, she was advised medication for 2 months to restore the health parameters to normalcy.
On repeated examination, her HbA1c readings were noted to be within normal range. Presurgical evaluation such as preoperative bone mapping and alveolar bone width assessment were done using a reliable diagnostic aid like cone beam computed tomography (CBCT). As residual ridge height was 3 mm (<5 mm), a lateral window approach for SFE with delayed implant placement to ensure primary stability was planned. Orthopantogram and CBCT scans were assessed in all possible sections, i.e., coronal, cross sectional and axial to get a clear picture of the sinus anatomy [Figure 1] and [Figure 2]. Radiological investigations were assessed to rule out the presence of pathology.
|Figure 2: Cone beam computed tomography sections demonstrating insufficient bony height (3 mm) for implant placement in the maxillary posterior region|
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To assess sinus anatomy details, the following parameters were evaluated:
- Height of the residual bone ridge,
- Vertical and mesiodistal extension of the maxillary sinus health conditions of the Schneiderian membrane
- Thickness of the lateral bone wall.
The height of the residual bone ridge allowed us to establish the important parameters: Lower limit of osteotomy choice of technique to be adopted.
Surgical procedure steps for lateral window antrostomy
Surgical area was locally anesthetized with 2% lignocaine and 1:100,000 epinephrine by the infiltration technique in maxillary 15.16 region.
A horizontal mid-crestal incision with a 15C blade was slightly beveled towards the palatal aspect. Anterior and posterior releasing incisions of sufficient length in a slightly flaring direction were made for sufficient access and a flap was made for good basal blood supply [Figure 3].
|Figure 3: A mid-crestal incision along with two facial vertical extensions are made and a trapezoidal mucoperiosteal flap is elevated to expose the lateral wall of the maxillary sinus|
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- Schematic diagram [Figure 4] representation of flap elevation showing a full thickness mucoperiosteal flap with wide base raised from the incision buccally.
- Superiorly, in the lateral sinus wall, the elevator was placed adherent to the bone surface to keep the periosteum intact
- The flap was extended 4–6 mm beyond the upper portion of the bony window. Ahead of the anterior border of sinus, a releasing incision distal to lateral incisor was given to avoid infra-orbital plexus.
|Figure 4: Schematic, diagram representation of flap elevation for window preparation|
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- Lateral window location was outlined with a sterile number 2 pencil on the buccal plate of bone, position of antrostomy being determined by size and location of the maxillary sinus as seen in the CBCT images.
- A straight hand piece was used with a round diamond SS White bur #4 to create a “window” in the lateral sinus wall as shown in schematic diagram [Figure 5] representing osseous window preparation
- The position of the window was approximately 3 mm from the sinus floor and 3 mm from the anterior wall, as this position greatly facilitates membrane elevation. The superior antrostomy was made at 15 mm from the crest to facilitate grafting to that height without having to release the membrane farther in the superior direction
- Specialized drills and curettes were used for this procedure
- In this technique, a drill was used to cut a round, bony island from the lateral wall like a trephine bur thus fracturing the bony plate rather than hinging the bone (trap door) into the sinus
- The drill was started at a desired location and proceeded further till a bluish hue shadow of the Schneiderian membrane was visible
- Then, the bony island was lifted up from the neighboring wall with a molt curette or periosteal elevator, removed and kept aside
- It was repositioned back to its original site after bone augmentation.
|Figure 5: Schematic, diagram representation of osseous window preparation|
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Sinus membrane elevation
- The intact membrane was visible with no bony septa over the membrane at the window created on the lateral wall [Figure 6]
- Schematic diagram represents careful detachment of the sinus membrane from the floor with the help of a sharp sinus curette [Figure 7]. It was followed by careful elevation of the sinus membrane at the inferior aspect, teasing it from the osseous wall of the sinus inferiorly, elevating it to include the medial wall of the sinus.
- Enough space was created for bone graft placement for the implant to be surrounded by bone later.
- The sharp part of the detacher was constantly maintained on the bone floor and membrane integrity was checked with Valsalva maneuver.
|Figure 6: Oval osseous window was carefully prepared on the lateral wall of the sinus using a large round diamond bur and bony window was kept aside to expose the sinus membrane without perforating it|
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|Figure 7: Schematic, diagram representation of careful elevation of the Schneiderian membrane to the desired height with the help of a special curette|
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- The schematic diagram represents gentle placement of graft materials in the space created post membrane elevation to ensure vascularization [Figure 8] However, some authors showed that sinus lift can be performed using the lateral approach with whole blood as the sole filling material with promising results.
- Graft materials -Bone substitutes like Bio-Oss (Xenograft) and Osteon (Alloplast) were used for the procedure along with resorbable bilayer Bio-Gide membrane for the augmentation procedure as shown in [Figure 9].
- Bone augmentation was performed by condensing a combination of bone graft materials such as 1cc Bio-Oss (Xenograft) and 0.5cc Osteon (Alloplast) in the sinus cavity post membrane elevation [Figure 10].
- The bony window was repositioned over the packed graft material and a resorbable, bilayer membrane, BIO GIDE was sutured over the lateral window to prevent invagination of soft tissue into the cavity during graft maturation in the healing period [Figure 11].
|Figure 8: Schematic, diagram representation of condensation of bone graft material in the sinus cavity|
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|Figure 9: Graft materials-bone substitutes-Bio-oss and osteon, resorbable bilayer Bio-gide membrane|
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|Figure 10: The elevated sinus floor space was packed with Xenograft (1cc Bio-Oss bone substitute) and Alloplast (0.5 cc Osteon) and bony window was repositioned|
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|Figure 11: Resorbable bilayer membrane (Bio-Gide) was sutured after repositioning the bony window|
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The procedure was completed by approximating the surgical site flaps with horizontal, mattress sutures using 3/8 circle reverse cutting 16 mm multiglyde needle suture for primary closure [Figure 12].
Postoperative instructions and care
- Following postoperative instructions were provided to the patient in both verbal and written forms
- Liquid diet for 2 days and then soft diet for 2 weeks
- Some nasal bleeding could occur on the first day.
- Medications – Antibiotic Tab. AugmentinR, 625 mg twice a day, Tab. MetrogylR, 400 mg, tds and Tab. EnzoflamR tds for 5 days,
- Chewing from the surgical site, blowing the nose for 2 weeks, smoking, sucking liquid with straw, carbonated drinks (minimum 3 days), vigorous exercise and playing musical instrument that requires blowing must be avoided by the patient during the 1st week after surgery. If the patient does sneeze, he or she must keep the mouth open, so that the pressure is not exerted within the sinus. For extraoral swelling, intermittent application of ice pack over the face was advised.
Postoperatively, the patient was followed up for checking complications, such as excessive bleeding, membrane perforation, swelling, pain, and nasal bleeding. There was no bleeding or facial swelling; however, patient experienced mild pain after surgery. On the 10th day postoperatively, the mucosal wound healed uneventfully. Other postoperative complications such as hematoma or loss of graft material did not occur. Radiographic images showed that the augmented bone graft formed a dome with a round margin under the elevated Schinederian membrane.
Increased Vertical Height Post Graft Maturation
Radiological image of the augmented bone height in the sinus was measured on the day of surgery and 8 months postoperatively. It was observed that there was an increase of 8 mm, the final achieved vertical bone height now being 11 mm. Ideal height was achieved for placement of implants ensuring primary stability in this otherwise surgically compromised case [Figure 13].
|Figure 13: Pre-op and Post-op radiological images post 8 months of direct sinus lift procedure depicting an increase of 8 mm residual bone height from 3 mm to 11 mm|
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Delayed implant placement with prosthesis delivery
Workflow followed 8 months postdirect sinus lift lateral window approach
- Pre-operative clinical picture [Figure 14] depicting complete healing of the intra-oral site, 8 months post the direct sinus lift surgery by lateral window approach.
- Surgical placement of 3 implants of 4/10 mm dimension implants in this maxillary posterior 13,15,17 region post flap elevation. [Figure 15]
- Placement of healing abutments in the second stage surgery. [Figure 16]
- Radiographic image showing the sinus membrane lining and the 3 surgically placed implants in sound bone post graft maturation with increased vertical bone height. [Figure 17]
- Definitive Prosthesis Delivered 6 months post implant placement. [Figure 18].
| Discussion|| |
- The lateral window technique formulated in 1970 by Tatum and modified by Boyne and James in 1980 for sinus augmentation to resolve deficient bone volume in atrophic posterior maxilla was well documented
- The transalveolar SFE, a less invasive and less costly alternative for sinus augmentation was designed by Summers in 1994. However, in surgically compromised cases, with residual bone height <5 mm, transcrestal procedures were more challenging and less predictable
- In the conventional lateral window approach, the size of bony window was usually large enough to provide direct visibility of the Schneiderian membrane and sinus floor
- Wallace recommended positioning the window approximately 3 mm from the sinus floor and 3 mm from the anterior wall, the superior border located 15 mm away from alveolar crest. According to his opinion, a larger window should be made in a procedure where more elevation of sinus floor was expected. Therefore, the apical-coronal height of the bony window could reach up to 11 mm in some cases
- Though transcrestal SFE was advocated for its minimal invasiveness, it was difficult to know the exact condition of the Schneiderian membrane without a direct surgical view. Thus, the lateral window technique is the method of choice, especially when sinus membrane elevation planned is more than 5 mm
- Several grafting materials have been used to increase bone height in the posterior maxilla. These include autogenous bone, allografts, xenografts, synthetic grafts, or combinations of any of these
- Autogenous bone has long been considered as the best option among all grafting materials as scientific evidence supports the idea that bone formation occurs through multiple pathways of osteoinduction, osteoconduction, and osteogenesis. Considering the relatively large volume of grafting material required, extraoral donor sites from the hip, tibia, or cranium were the additional sources to provide an adequate amount of autogenous bone for sinus augmentation. However, donor site morbidity was considered a huge drawback in contemplating the exclusive use of autogenous bone for implant surgery
- Therefore, in present case, a combination of xenograft and alloplast bone graft materials along with guided tissue regeneration barrier membrane extending a few mm over the lateral window were used. Delayed surgical placement of implants was successfully executed with subsequent prosthesis delivery.
- Although sinus grafting is considered to be a relatively invasive surgical procedure, the incidence of reported surgical and postsurgical complications was relatively low.
| Conclusion|| |
The maxillary sinus elevation procedure has been proposed as one of the most useful preprosthetic surgical technique for oral rehabilitation by dental implants in the surgically compromised atrophic maxilla. Considerable improvement regarding the flap design, method of surgical approach, specially designed instruments, and various bone grafts or bone substitutes have been proposed for over a decade. Finally, from a radiologic and histologic point of view, the lateral window approach in conjunction with bone grafts for regenerating lost osseous structure in surgically compromised atrophic, posterior maxilla is the method of choice for successful and predictable outcome.
In this case, implant survival was defined when the prosthesis had been delivered and followed up for 2 years with no biological or biomechanical complications [Figure 19].
Declaration of consents
The authors certify that they have obtained all appropriate informed consents from the patient and dentium implant company for use of diagrammatic representations from their catalog for explanatory purpose toward publication of the case.
The authors are grateful to their dental technician and auxiliary team in private for their support in this clinical work.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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