Predictors For Transosseous Maxillary Sinus Lift Complications: A Prospective Cohort Study
Phase: NA
Conditions: Sinus Lift Surgery Complications, Maxillary Sinus Elevation
Sponsor: University of Baghdad

                                                                                                                                          
Predictors For trans osseous Maxillary Sinus Lift Complications: A 
Prospective Cohort Study 
Document Date: May 26, 2025 
Abstract    
Background: Transosseous maxillary sinus lift (MSL) procedures are widely used to augment bone 
height in the posterior maxilla, allowing for successful dental implant placement in cases with limited 
bone availability. However, complications such as sinus membrane perforation, postoperative 
infections, and insufficient bone gain remain significant clinical challenges. Identifying the predictors 
of these complications is critical for improving patient outcomes and enhancing surgical protocols. 
Aim: This study aims to identify preoperative, intraoperative, and patient-related factors that predict 
the occurrence of complications during transosseous MSL procedures. Specifically, the study will focus 
on identifying risk factors for sinus membrane perforation, infection. 
Materials and Methods: A prospective cohort of patients requiring MSL procedures will be enrolled. 
Preoperative assessments will include radiographic evaluations of the residual ridge height, sinus 
membrane thickness, site of surgery amount of vertical lifting, and MSO assessment. Intraoperative 
variables such as surgical approach, bone graft materials. Postoperative complications, including 
membrane perforation and infection, will be recorded. Statistical analysis will identify correlations 
between these variables and adverse outcomes. 
Conclusion: This study protocol outlines a comprehensive approach to evaluating the predictors of 
complications in MSL procedures. The results are expected to provide valuable insights that can 
improve clinical practice and patient care in the context of dental implantology. 
	
	
	
	
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Introduction  
Transosseous maxillary sinus lift, also known as the crestal or transcrestal approach, has become a 
valuable technique for augmenting bone height in the posterior maxilla, offering a less invasive 
alternative to the lateral window technique. However, complications such as sinus membrane 
perforation, graft displacement, and implant failure can occur, necessitating the identification of 
predictors to mitigate these risks (Nedir et al., 2023). Recent studies emphasize that factors such as 
the initial bone height, sinus membrane thickness, and residual bone volume play crucial roles in 
predicting complications (Marenzi et al., 2022). For instance, a residual bone height of less than 4 mm 
significantly increases the risk of membrane perforation, while thicker sinus membranes are 
associated with a reduced risk (Nedir et al., 2023). Smoking and patient age are also considered key 
risk factors for complications, as smoking impairs healing, and older patients often exhibit poorer bone 
quality (Li et al., 2022). Recent advancements, such as the use of hydraulic lift techniques or 
piezoelectric surgery, have shown promise in reducing complication rates by improving control over 
membrane elevation (Fayad et al., 2023). A randomized controlled clinical trial is well-suited to 
comprehensively evaluate these factors, providing valuable insights into optimizing patient selection 
and surgical technique for the transosseous sinus lift approach.  
a study by Antonelli et al. in 2024 demonstrated that implant survival rates in transosseous lifts are 
high, with minimal surgical complications like membrane perforations occurring in less than 2% of 
cases. The researchers noted that bone graft materials, including injectable xenografts, contributed to 
stable long-term outcomes . Similarly, other studies have identified the thickness of the Schneiderian 
membrane and residual bone height as essential for predicting successful outcomes in osteotome 
sinus floor elevations . These predictors help in tailoring treatment plans to minimize complications 
and improve overall implant success. 
	
	
	
	
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Research Question 
What are the key predictors of complications during transosseous maxillary sinus lift 
procedures, and how do anatomical factors, surgical techniques, and graft materials 
influence these outcomes? 
AIM& OBJECTIVES 
1. Investigating the impact of patient-specific anatomical factors on complication rates.  
2. Assessing the role of surgical techniques and graft materials in influencing 
complications.  
3. Developing a predictive framework to enhance surgical planning and safety in sinus 
lift procedures. 
HYPOTHESIS 
•Null Hypothesis (H0): There is no significant association between patient-specific 
factors (e.g., RBH, sinus membrane thickness, MSO, amount of vertical lifting and site of 
surgery) and the occurrence of complications during or after transosseous maxillary 
sinus lift procedures.  
•Alternative Hypothesis (H1): Certain patient-specific factors (e.g. MSO, sinus 
membrane thickness, RBH) and surgical factors (e.g., graft material, surgical technique, 
	
	
	
	
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site of surgery and amount of vertical lifting) are significantly associated with an 
increased risk of complications (e.g., membrane perforation, infection, graft failure) in 
transosseous maxillary sinus lift procedures. 
Methodology  
Study design : Prospective, cohort study. 
Setting site : Department of Oral and Maxillofacial surgery / College of Dentistry / 
Baghdad University. 
Sample Size : 171 
The literature mentioned that sinus membrane perforation occurred in 7-8% of the 
cases treated by the trans crystal approach, whether by summer and modified summer 
technique or by rotary drills.  
G power software was used to estimate the required sample size to predict the 
possibility of sinus membrane perforation with a transrectal approach where linear 
multiple regression was performed using a fixed model with an R2 deviation from the 
zero equation from the F test family. The effect size was calculated by determining the 
odd ratio (0.0753) with a 7% complication rate. From this odd ratio, the effect size was 
calculated to be 1. which is expected because of the low incidence rate of perforation 
associated with such procedures.  
	
	
	
	
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0The power of the study is set at 90%, and the alpha error is 0.05. The number of 
predictors that need to be tested is 5. The total required sample size is 171. 
Study Duration: 2 years. 
Inclusion Criteria 
1- Patients requiring dental implants in the posterior maxilla with a residual bone height 
of < 6 mm.  
2-  Good general health and absence of systemic conditions affecting bone healing (e.g., 
uncontrolled diabetes, osteoporosis). 
3-  No history of chronic sinusitis or other significant sinus pathologies 
Exclusion Criteria   
1- Severe periodontal disease.  
2- Residual bone height > 6 mm. 
3- History of previous sinus lift procedures or other maxillofacial surgeries. 4- Smokers. 
Outcome Measures 
	
	
	
	
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The primary outcome measure will be the incidence of sinus membrane perforation , 
Graft displacement. its predictors. Secondary outcomes include rates of infection, and 
patient-reported satisfaction. 
STATISTICAL ANALYSIS  
• Predictor Variables: 
1- Pre-operative sinus membrane thickness (using CBCT). 2- Residual bone height RBH . 
3- Site of surgery ( tooth number ).  
4- Amount of vertical lifting. 
5- Maxillary sinus ostium assessment (using CBCT).  
• Outcome Variables:  
• 1- Presence or absence of complications.  
• 2- Bone height gain.  
• • Statistical Tests:  
• • Logistic regression to identify predictors of complications.  
• • ANOVA or t-tests to compare bone gain. 
Surgical Procedure  
	
	
	
	
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1.  Preoperative Preparation and Anesthesia Patient Positioning and Aseptic Technique: 
Position the patient in a supine position with the head slightly extended. Use a sterile 
draping technique and administer local anesthesia (e.g., lidocaine with epinephrine) at 
the surgical site to ensure effective anesthesia and hemostasis (Greenstein & Cavallaro, 
2011).  
2.  CBCT Analysis: Preoperative cone beam computed tomography (CBCT) is used to 
assess residual bone height (RBH), sinus membrane thickness (Figure1), MSO (Figure 2), 
and overall sinus anatomy, which are critical for planning the sinus lift procedure (Chan 
et al., 2022). 
3.   Initial Osteotomy Preparation Pilot Drill to Penetrate the Cortical Bone: Start with a 
small-diameter pilot drill to create an initial osteotomy, stopping just short of the sinus 
floor to avoid perforation. The osteotomy depth depends on the RBH measured 
preoperatively (Pjetursson et al., 2008). Versah Densah Burs in Counterclockwise 
(Osseodensification) Mode: Select the first Densah bur according to the diameter of the 
planned implant. Use the bur in reverse mode to create a controlled, condensed 
osteotomy that pushes bone particles outward, preserving and compacting bone along 
the osteotomy walls (Huwais & Meyer, 2017). Using the Densah burs in 
counterclockwise mode (800-1500 rpm with irrigation), the initial 2.0 mm bur prepares 
the osteotomy just shy of the sinus floor. The burs’ unique densifying action pushes 
bone particles laterally and apically, compacting the bone and preserving cortical 
	
	
	
	
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thickness for increased stability (Fayad et al., 2023). Larger burs are then applied in 
sequence (e.g., 3.0 mm,  
4.0 mm), gently lifting the Schneiderian membrane through controlled pressure and 
compacted bone. 
The postoperative immediate P.A X-ray showed a dome shape of lifting, which  indicates 
an  intact  sinus  membrane.  This  dome-shaped  appearance  on radiographs is often 
seen as a positive sign following sinus lift procedures, as it suggests that the membrane 
was successfully elevated without perforation or damage (Chen & Cha, 2021). 
4-Postoperative Protocol 
Suturing and Patient Instructions: Close the site with non- resorbable sutures and 
provide standard postoperative instructions. Advise the patient to avoid actions that 
increase sinus pressure, such as blowing the nose forcefully, sneezing with a closed 
mouth, or using a straw (Wallace & Froum, 2003). • Follow-Up Appointments: Schedule 
follow-ups at 1 week, 1 month, and 3 months to monitor healing, and the stability of 
the graft (Nedir et al., 2017). 
Ethical Considerations  
• Obtain informed consent from all participants.  
	
	
	
	
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• Ensure the study is approved by an institutional review board (IRB).  
• Follow ethical guidelines for clinical trials and patient safety protocols. 
References 
• Nedir, R., Bischof, M., Szmukler-Moncler, S., & Bernard, J. P. (2023) ‘Factors affecting 
sinus membrane perforation in transcrestal sinus floor elevation: A retrospective clinical 
study’, Journal of Oral Implantology, 49(1), pp. 58-64.  
• Marenzi, G., Pellegrino, G., Raspanti, M., & Sammartino, G. (2022) ‘Sinus membrane 
management in atrophic posterior maxilla with minimal bone height: A review of recent 
techniques’, Journal of Oral and Maxillofacial Surgery, 80(8), pp. 1324-1333.  
	
	
	
	
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• Li, J., Zhou, Y., & Wang, F. (2022) ‘Influence of smoking and age on sinus floor 
augmentation outcomes’, Clinical Implant Dentistry and Related Research, 24(3), pp. 
210-217. 
• Fayad, M., Ashmawy, A., & AbuBakr, N. (2023) ‘Influence of osseodensification on 
implant stability and bone gain in sinus lift procedures’, International Journal of Oral 
and Maxillofacial Implants, 38(5), pp. 914-921. 
• Antonelli A, et al. Implant survival rates and predictors of complications in 
transosseous sinus lifts: A randomized controlled trial. Journal of Oral Implantology. 
2024;45(2):123-130.  
• Al-Jewair, T. S., Elshourbagy, E., & Basma, H. (2022). Clinical outcomes of 
osseodensification in maxillary sinus augmentation. Clinical Oral Implants Research, 
33(8), 774-782. 
• • Fayad, M., Ashmawy, A., & AbuBakr, N. (2023). Influence of osseodensification on 
implant stability and bone gain in sinus lift procedures. International Journal of Oral 
and Maxillofacial Implants, 38(5), 914-921.  
• • Malik, A., Trivedi, P., & Bhasin, P. (2023). Comparative analysis of sinus lift 
techniques in compromised maxillary regions. Journal of Oral Implantology, 49(4), 
265-273.  
	
	
	
	
 
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• • da Silva, A. C., Pereira, D. S., & Franco, L. C. (2021). Osseodensification for sinus floor 
elevation: Clinical case series and literature review. Journal of Dental Research and 
Review, 8(2), 105-112 
• • Chan, H. L., Suarez, F., Monje, A., & Galindo-Moreno, P. (2022). Current status of 
maxillary sinus augmentation and future directions: A systematic review. Journal of 
Clinical Periodontology, 49(Suppl. 24), 181–198.  
• • Chen, L., & Cha, J. (2021). Immediate and early implant placement with sinus 
membrane elevation without grafting using hydraulic pressure: a novel technique. 
Clinical Implant Dentistry and Related Research, 23(1), 46-55. 
• • Del Fabbro, M., Rosano, G., & Taschieri, S. (2012). Implant survival rates after 
maxillary sinus augmentation. European Journal of Oral Implantology, 5(1), 25-34. 
• • Greenstein, G., & Cavallaro, J. (2011). The clinical significance of sinus membrane 
perforation during sinus augmentation procedures. Compendium of Continuing 
Education in Dentistry, 32(4), e83-e91. 
• • Huwais, S., & Meyer, E. (2017). Osseodensification: A novel approach in implant 
osteotomy preparation to increase primary stability, bone mineral density, and bone-
to-implant contact. International Journal of Oral & Maxillofacial Implants, 32(1), 
27-36.  
	
	
	
	
 
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• • Nedir, R., Nurdin, N., Khoury, P., & Bischof, M. (2017). Osteotome sinus floor 
elevation without grafting material: A 10-year prospective study. Clinical Implant 
Dentistry and Related Research, 19(1), 56-64. 
• • Pjetursson, B. E., Tan, W. C., Zwahlen, M., & Lang, N. P. (2008). A systematic review 
of the success of sinus floor elevation and survival of implants inserted in 
combination with sinus floor elevation. Journal of Clinical Periodontology, 35, 
216-240. 
• • Trisi, P., Berardi, D., Paolantonio, M., & D’Addona, A. (2016). New osseodensification 
implant site preparation technique and osseointegration: A histological and 
biomechanical evaluation in implant immediate loading. International Journal of Oral 
and Maxillofacial Implants, 31(3), 543–549. 
• • Wallace, S. S., & Froum, S. J. (2003). Effect of maxillary sinus augmentation on the 
survival of endosseous dental implants: A systematic review. Annals of 
Periodontology, 8(1), 328-343 
• • Peter, S.S., Nambiar, P., Krishnan, S. and Al-Namnam, N.M., 2020. The location and 
diameter of the primary maxillary sinus ostium: A cone-beam computed tomography 
study in Malaysians. Journal of International Dental and Medical Research, 13(1), 
pp.1-8. 
	
	
	
	
 
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• • Munakata, M., Yamaguchi, K., Sato, D. and Tachikawa, N., 2021. Factors influencing 
the sinus membrane thickness in edentulous regions: a cone-beam computed 
tomography study. International Journal of Implant Dentistry, 7(1), p.26.
	
	
	
	
 
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