The International Journal of Periodontics & Restorative Dentistry

Transcription

1 The International Journal of Periodontics & Restorative Dentistry

2 413 Schneiderian Membrane Perforation Rate During Sinus Elevation Using Piezosurgery: Clinical Results of 100 Consecutive Cases Stephen S. Wallace, DDS 1 /Ziv Mazor, DMD 2 Stuart J. Froum, DDS 3 /Sang-Choon Cho, DDS 4 /Dennis P. Tarnow, DDS 5 The lateral window sinus elevation procedure has become a routine and highly successful preprosthetic procedure that is used to increase bone volume in the posterior maxilla for the placement of dental implants. Many surgical techniques have been proposed that provide access to the maxillary sinus through the lateral wall to allow for elevation of the sinus membrane. Among these are the multiple variations of the hinge and complete osteotomy techniques, which make use of rotary cutting instruments for the antrostomy. The most common intraoperative complication with these surgical approaches is perforation of the schneiderian membrane, with perforation rates of 14% to 56% reported in the literature. In most instances, perforation occurs either while using rotary instruments to make the window or when using hand instruments to gain initial access to begin the elevation of the membrane from the sinus walls. This article presents an alternative approach that uses a piezoelectric instrument for the sinus elevation procedure. Although new to the United States, this approach has been used successfully in Europe for many years. The membrane perforation rate in this series of 100 consecutive cases using the piezoelectric technique has been reduced from the average reported rate of 30% with rotary instrumentation to 7%. Furthermore, all perforations with the piezoelectric technique occurred during the hand instrumentation phase and not with the piezoelectric inserts. (Int J Periodontics Restorative Dent 2007;27: ) 1 Clinical Associate Professor, New York University Department of Periodontics and Implant Dentistry, New York, New York. 2 Private Practice, Ra anana, Israel. 3 Clinical Professor, Director of Clinical Research, New York University Department of Periodontics and Implant Dentistry, New York, New York. 4 Assistant Clinical Professor, Associate Director of Clinical Research, New York University Department of Periodontics and Implant Dentistry, New York, New York. 5 Professor and Chairman, New York University Department of Periodontics and Implant Dentistry, New York, New York. Correspondence to: Dr Stephen Wallace, 140 Grandview Avenue, Waterbury, CT 06708; sswdds.sinus@sbcglobal.net. Sinus augmentation surgery has become a well-accepted preprosthetic procedure for creating sufficient bone volume for the placement of endosseous implants in the atrophic posterior maxilla. 1 4 This technique, first presented by Tatum 5 in 1977 and first published in 1980 by Boyne and James, 6 has since undergone many modifications. The lateral window approach today uses many antrostomy designs. The procedure is most often initiated with various forms of rotary surgical instrumentation, such as an electric or air-driven handpiece with diamond or carbide burs. The actual elevation of the schneiderian membrane, performed prior to placement of the bone graft, is typically performed with hand instrumentation. The piezoelectric sinus elevation technique uses an improved and sophisticated ultrasonic (piezoelectric) device (Piezosurgery Inc). The device operates at a variable modulated frequency (24.7 to 29.5 KHz) that is designed to cut or grind bone but not damage adjacent soft tissues. It uses specifically designed osteotomy (cutting) and osteoplasty (grinding) inserts for making the antrostomy. Volume 27, Number 5, 2007

3 414 Initial membrane elevation is performed with a unique blunt elevator that further protects the integrity of the membrane by providing a cavitating saline spray. The most frequent intraoperative complication with sinus elevation surgery is the perforation of the schneiderian membrane. This paper presents the initial clinical experience with regard to perforation rates observed in consecutive lateral window sinus elevations performed in the private practices of five experienced surgeons, all but one of whom were new to the piezoelectric sinus elevation technique. Method and materials Clinical data for this study were obtained from the private practices of the participating clinicians. The data include the initial lateral window entries using the Piezosurgery device, which were performed following a single trial case used to gain familiarity (learning curve) with the device. All patients required maxillary sinus elevation for the placement of endosseous implants, were medically qualified to receive such therapy, and signed appropriate consent forms. A database was established to report observed sinus membrane perforations. Occurrences of perforations were recorded, as were the types of inserts used. Membrane thickness as measured by computerized tomographic (CT) analysis was also recorded, because this anatomic factor has been linked to perforation rates. A total of 100 grafted sinuses were included in this case series. Results One hundred sinus elevations were performed, and there were seven perforations. None of the perforations occurred during the antrostomy and initial membrane elevation with the piezo inserts. The seven perforations that occurred upon continued membrane elevation with conventional hand instruments were related to the presence of a septum (n = 4) and an extremely thin membrane (n = 3). The overall membrane perforation rate was 7%. The perforation rate with the piezoelectric inserts was 0%. Because the number of perforations was limited to seven, it was not possible to attribute any statistical difference to the perforation rates of thick (> 1 mm) versus thin ( 1 mm) membranes. Eighty-seven of the lateral walls were > 1 mm in thickness; these windows were created with the OP-3 and OT-1 inserts. The remaining 13 were 1 mm in thickness, and these windows were made using osteoplasty instruments such as the OT-5 diamond ball or the OT-1 diamond scalpel. Discussion Piezoelectric bone surgery has been used for many intraoral dental and implant procedures. The use of this technique for sinus elevation surgery has been described by Vercellotti and coworkers. 7,8 Not only is this technique clinically effective, but histologic and histomorphometric evidence of wound healing and bone formation in the dog model has been presented to show that the tissue The International Journal of Periodontics & Restorative Dentistry

4 415 Fig 1 (left) insert. Fig 2 (right) OT-5 diamond ball smoothing OP-3 osteoplasty insert. Fig 3 (left) Fig 4 (right) elevator. OT-1 diamond scalpel. EL-1 rounded noncutting response is more favorable to Piezosurgery than it is to diamond or carbide rotary instrumentation. 9 The piezoelectric ultrasonic device used in this study (Piezosurgery) is designed to operate at a low frequency of 24.7 to 29.5 KHz, producing microvibrations (20 to 60 µm) that are ideal for ostectomy and osteoplasty but allow for the preservation of soft tissue. The various inserts used in this study were specifically designed for sinus elevation surgery. Light handpiece pressure and an integrated saline coolant spray keep the temperature low and visibility of the surgical site high. It is claimed that inadvertent perforations of the sinus membrane are unlikely when piezosurgical techniques are appropriately applied. In a series of 21 bony windows and membrane elevations performed with piezoelectric surgery, only 1 perforation was reported. 7 Both hinge and complete antrostomies can be performed with this device using the sinus inserts shown in Figs 1 to 4. When the lateral wall is thin, Volume 27, Number 5, 2007

5 416 Fig 5 (left) Osteotomy in thin lateral wall with OT-5 insert. Fig 6 (right) An osteoplasty was accomplished with the OP-3 to thin the wall, then the osteotomy was completed with the OT-1. Fig 7 In a different case, membrane elevation is initiated with EL-1 elevator. Fig 8 Membrane elevation is completed with hand instrumentation. Fig 9 Artery in lateral wall. Fig 10 Red circle indicates the artery in the lateral wall (CT paraxial view). The International Journal of Periodontics & Restorative Dentistry

6 417 it may be convenient to use the diamond ball smoothing insert (OT-5) or the diamond scalpel (OT-1) to outline the window (Fig 5). If the wall is thick, it is less time consuming to first reduce the thickness of the wall with the osteoplasty insert (OP-3) and then refine the window with the diamond-coated smoothing insert (OT-1) (Fig 6). The bone removed by osteoplasty can be harvested and incorporated within the sinus graft. The initial release of the membrane from the antrostomy edges is performed with a dull, rounded, noncutting elevator (EL-1) that works with saline cavitation to safely create a small internal elevation (Fig 7). The procedure is complete with conventional sinus membrane elevators (Fig 8). The most common intraoperative complication of sinus elevation surgery is perforation of the schneiderian membrane. A review of the literature reveals that schneiderian membrane perforation rates in lateral window sinus elevation surgery vary from 14% to 56%. 10 The perforation rate in the present case series was 7% (7 of 100 sinuses), which is significantly lower than that reported in the literature. It is the experience of our research group that the expected membrane perforation rate is in the range of 25% to 30%. Further, the occurrence of perforations appears to be equally attributable to rotary instrumentation, initial release of the membrane at the antrostomy margin with hand instruments, and the continued elevation of the membrane from the internal sinus walls. In this series of cases, perforations were completely eliminated during the antrostomy preparation and during the initial membrane release phases of the surgery. If this trend continues, Piezosurgery offers a 75% reduction in the expected perforation rate to the 7% observed in this series. There is some debate in the literature as to whether membrane perforations affect the outcome of sinus elevation surgery as measured by vital bone formation and/or implant survival. Data from Proussaefs et al 11 showed vital bone formation of 33.6% versus 14.2% and implant survival of 100% versus 70%, respectively, for nonperforated and perforated cases. Khoury 12 reported 14 of 28 implant failures (statistically high) in cases with perforations. Of 164 implant failures included in the Sinus Consensus Conference clinician survey, 1 79 involved perioperative complications, of which 38 had identified sinus perforations. In contrast to these findings are reports by Schwartz-Arad et al 13 and Ardekian et al, 14 which showed no difference in implant survival with respect to membrane perforations. Regardless of the effect on outcome parameters, perforations must still be repaired to complete the grafting procedure. Repairing perforations may be simple, difficult, or perhaps impossible. If the perforation cannot be repaired, procedures using particulate graft materials will most likely have to be abandoned. Membrane repair techniques using bioabsorbable collagen barrier membranes have been reported by Pikos, 15 Vlassis and Fugazzotto, 16,17 Proussaefs and Lozada, 18 and Wallace et al. 19 A recent clinical report by Testori et al 10 provided clinical, histologic, and histomorphometric evidence of successful therapy when very large perforations have been adequately repaired. At best, even a simple repair with a bioabsorbable collagen barrier membrane increases the cost of the procedure. More involved repairs, however, increase the time necessary to complete the procedure and may therefore result in increased patient morbidity, including postoperative edema and sinus congestion. The increased operative time may also result in a higher sinus graft infection rate, as it offers more opportunity for contamination of the graft or repair membrane from intraoral bacteria. A second intraoperative complication of sinus elevation surgery is the profuse bleeding that sometimes occurs when performing the antrostomy with rotary cutting instruments. This occurs when the anastamosis of the lower branch of the posterior superior alveolar artery and the infraorbital artery is severed, usually with the vertical osteotomy cuts. This artery is present in 100% of cadaver specimens 20 and can be located in 52% of CT studies. 21 Figure 9 shows the clinical appearance of a relatively large artery, and Fig 10 shows its location in the lateral wall in a paraxial CT view. Bleeding from this artery is usually minimal, but sometimes it can be of a magnitude that makes it impossible to continue the procedure until the bleeding is controlled. In some instances this can take 20 minutes or more, again increasing the operative time and likewise increasing the likelihood of postoperative edema and ecchymosis. The use of piezoelectric inserts allows for antrostomy preparation without injury to the vessels in the lateral wall, as the inserts Volume 27, Number 5, 2007

7 418 Fig 11 (left) Intact artery in lateral wall after removal of superficial bone with OP-3 insert; the osteotomy is refined with the OT- 1 insert. Fig 12 (right) Intact artery completely dissected from window. do not cut soft tissue. Figures 11 and 12 show preservation of this artery using piezoelectric surgical techniques. Conclusions While piezoelectric surgery is relatively new in the United States, it has been used with excellent results in Europe for more than 10 years. The following advantages have been shown in sinus elevation surgery using piezoelectric techniques: 1. Reduced membrane perforation rate 2. Improved intraoperative visibility 3. Reduced intraoperative bleeding 4. Reduced surgical trauma References 1. Jensen OT, Shulman LB, Block MS, Iacono VJ. Report of the Sinus Consensus Conference of Int J Oral Maxillofac Implants 1998;13: Wallace SS, Froum SJ. Effect of maxillary sinus augmentation on the survival of endosseous dental implants: An evidencebased literature review. Ann Periodontol 2003;8: Del Fabbro M, Testori T, Francetti R, Weinstein R. Systematic review of survival rates for implants placed in the grafted maxillary sinus. Int J Periodontics Restorative Dent 2004;24: Aghaloo TL, Moy PK. What hard tissue augmentation techniques are the most successful in furnishing bony support for implant placement? Int J Oral Maxillofac Implants 2007;22(suppl): Tatum OH. Maxillary sinus grafting for endosseous implants. Presented at the Annual Meeting of the Alabama Implant Study Group, Birmingham AL, April Boyne PJ, James RA. Grafting of the maxillary sinus floor with autogenous marrow and bone. J Oral Surg 1980;38: Vercellotti T, De Paoli S, Nevins M. The piezoelectric bony window osteotomy and sinus membrane elevation: Introduction of a new technique for simplification of the sinus augmentation procedure. Int J Periodontics Restorative Dent 2001; 21: Vercellotti T, Nevins ML, Jensen O. Piezoelectric surgery for sinus bone grafting. In: Jensen O (ed). The Sinus Bone Graft, ed 2. Chicago: Quintessence, 2006: Vercellotti T, Nevins ML, Kim DM, et al. Osseous response following resective therapy with piezosurgery. Int J Periodontics Restorative Dent 2005;25: Testori T, Wallace SS, Del Fabbro M, et al. Repair of large sinus membrane perforations using stabilized collagen membranes: Surgical techniques with histologic and radiographic evidence of success. Int J Periodontics Restorative Dent (in press). 11. Proussaefs P, Lozada J, Kim J, Rohrer MD. Repair of the perforated sinus membrane with a resorbable collagen membrane: A human study. Int J Oral Maxillofac Implants 2004;19: The International Journal of Periodontics & Restorative Dentistry

8 Khoury F. Augmentation of the sinus floor with mandibular bone block and simultaneous implantation: A 6-year clinical investigation. Int J Oral Maxillofac Implants 1998;14: Schwartz-Arad D, Herzberg R, Dolev E. The prevalence of surgical complications of the sinus graft procedure and their impact on implant survival. J Periodontol 2004;75: Ardekian L, Oved-Peleg E, Mactei EE, Peled M. The clinical significance of sinus membrane perforation during augmentation of the maxillary sinus. J Oral Maxillofac Surg 2006;64: Pikos MA. Maxillary sinus membrane repair: Report of a technique for large perforations. Implant Dent 1999;8: Vlassis JM, Fugazzotto PA. A classification system for sinus membrane perforations during augmentation procedures with options for repair. J Periodontol 1999;70: Fugazzotto P, Vlassis J. A simplified classification and repair system for sinus membrane perforations. J Periodontol 2003;74: Proussaefs P, Lozada JL. The Loma Linda pouch: A technique for repairing the perforated sinus membrane. Int J Periodontics Restorative Dent 2003;23: Wallace SS, Froum SJ, Tarnow DP. Use of barrier membranes in sinus augmentation. In: Jensen O (ed). The Sinus Bone Graft, ed 2. Chicago: Quintessence, 2006: Solar P, Geyerhofer U, Traxler H. Blood supply to the maxillary sinus as it relates to maxillary sinus elevation. Clin Oral Implants Res 1999;10: Elian N, Wallace SS, Cho S-C, Jalbout Z, Froum SJ. Distribution of the maxillary artery as it relates to maxillary sinus augmentation. Int J Oral Maxillofac Implants 2005;20; Volume 27, Number 5, 2007