Functional Mandibular Reconstruction With Double-Barrel Fibular Flap and Primary Osseointegrated Dental Implants Improve Facial Esthetic Outcome

Custom Endoprosthesis-Assisted Pediatric Microsurgical Jaw Reconstruction

Surgical treatment of pediatric maxillary and mandibular tumors can cause significant postresection disfigurement, mastication, and speech dysfunction. The need to restore form and function without compromising growth at the recipient and donor sites poses a particular reconstructive dilemma. This study evaluates outcomes of the custom endoprosthesis (CE) compared with noncustom reconstruction (NCR) and introduces an algorithm using CE to optimize available soft tissue reconstructive options. An Institutional Review Board-approved retrospective review of all patients undergoing maxillary or mandibular reconstruction between 2016 and 2022 was completed. The independent variable of interest was CE utilization. Primary outcomes of interest included hardware failure/removal or exposure, major complications, and revision surgeries. Covariates of interest included patient demographics, medical comorbidities, tumor size, and pathologic diagnosis. Statistical analyses including independent t test, χ2 analyses, and univariate/multivariate logistic regression were performed using RStudio version 4.2.1. Fifty-one patients (37 mandible and 14 maxilla) underwent CE or NCR. Of patients, 37% (n = 19) received CE. Of patients who underwent mandibular reconstruction, there were significantly lower rates of hardware exposure (14.3% versus 47.8%, P = 0.018), failure (7.1% versus 43.5%, P = 0.048), major complications (28.6% versus 78.2%, P = 0.008), and revisions (11.1% versus 50.0%, P = 0.002) in the CE cohort compared with the NCR cohort. The rates of hardware failure, exposure, major complications, and revisions did not significantly differ in maxillary reconstructions, however, CE successfully reconstructed significantly larger defects (179.5 versus 74.6 cm3, P = 0.020) than NCRs. Deviating from NCR, the authors propose an algorithm considering anatomical location, extent of resection, and patient age for soft tissue selection. This algorithm yielded improved mandibular reconstructive outcomes and no increase in complications rate in maxillary reconstruction despite larger resection defects. Furthermore, the authors' initial findings demonstrate that CE is a safe option for pediatric maxillary and mandibular reconstruction that may, in addition, facilitate improved form and function.

Reconstruction of Segmental Mandibular Defects with Double-Barrel Fibula Flap and Osseo-Integrated Implants: A Systematic Review

Background: Mandibular defects resulting from oncological treatment pose significant aesthetic and functional challenges due to the involvement of bone and soft tissues. Immediate reconstruction is crucial to address complications such as malocclusion, mandibular deviation, temporomandibular joint (TMJ) changes, and soft tissue retraction. These issues can lead to functional impairments, including difficulties in chewing, swallowing, and speech. The fibula flap is widely used for mandibular reconstruction due to its long bone segment and robust vascular supply, though it may not always provide adequate bone height for optimal dental rehabilitation. This systematic review aims to determine if the double-barreled fibula flap (DBFF) configuration is a viable alternative for mandibular reconstruction and to evaluate the outcomes of dental implants placed in this type of flap. Materials and Methods: This study adhered to the Cochrane Collaboration criteria and PRISMA guidelines and was registered on the International Platform of Registered Systematic Review and Meta-Analysis Protocols Database (INPLASY2023120026). We included clinical studies published in English, Spanish, or French that focused on adult patients undergoing segmental mandibulectomy followed by DBFF reconstruction and dental rehabilitation. Data sources included Medline/PubMed, the Cochrane Library, EMBASE, Scopus, and manual searches. Two reviewers independently screened and selected studies, with discrepancies resolved by a third reviewer. Data extraction captured variables such as publication year, patient demographics, number of implants, follow-up duration, flap survival, implant failure, and aesthetic outcomes. The risk of bias was assessed using the JBI appraisal tool, and the certainty of evidence was evaluated using the GRADE approach. Results: A total of 17 clinical studies were included, evaluating 245 patients and 402 dental implants. The average patient age was 43.7 years, with a mean follow-up period of 34.3 months. Flap survival was high, with a 98.3% success rate and only four flap losses. The implant failure rate was low at 1.74%. Esthetic outcomes were varied, with only three studies using standardized protocols for evaluation. The overall certainty of evidence for flap survival was moderate, low for implant failure, and very low for aesthetics due to the subjective nature of assessments and variability in reporting. Conclusions: The primary limitations of the evidence included in this review are the observational design of the studies, leading to an inherent risk of bias, inconsistency in reporting methods, and imprecision in outcome measures. Additionally, the subjective nature of aesthetic evaluations and the variability in assessment tools further limit the reliability of the findings. The DBFF technique demonstrates excellent outcomes for mandibular reconstruction, with high flap survival and low implant failure rates, making it a viable option for dental rehabilitation. However, the evidence for aesthetic outcomes is less certain, highlighting the need for more rigorous and standardized research. This review supports the DBFF as a good alternative for mandibular reconstruction with successful dental implant integration, although further studies are needed to enhance the reliability of aesthetic evaluations.

Efficacy of personalized 3D-printed osteotomy guide in maximizing fibular utilization and minimizing graft length for reconstruction of large mandibular defect

OBJECTIVE

The study addresses the long-standing challenge of insufficient length in vascularized fibular flaps when reconstructing large mandibular defects that require dual-barrel grafts. Employing personalized 3D-printed osteotomy guides, the study aims to optimize fibular utilization and minimize the required graft length.

MATERIAL AND METHODS

Two reconstruction methods for distal bone defects were compared: a fold-down (FD) group that employed a specialized osteotomy guide for folding down a triangular bone segment, and a traditional double-barrel (DB) group. Metrics for comparison included defect and graft lengths, as well as the graft-to-defect length ratio. Postoperative quality of life was assessed using the University of Washington Quality of Life questionnaire (UW-QoL).

RESULT

Both FD and DB groups achieved successful mandibular reconstruction. Despite larger defects in the FD group (117 ± 31.35 mm vs 84 ± 35.34 mm, p = 0.028), the used fibula length was not statistically longer in the FD group. The median ratio of graft-to-defect length was also lower in the FD group (1.327 vs 1.629, p = 0.024), suggesting that FD required only 82.47% of the graft length needed in the DB approach. Quality of life scores post-surgery were comparable between the groups.

CONCLUSION

Personalized 3D-printed osteotomy guides enhance fibula graft efficacy for reconstructing larger mandibular defects, necessitating shorter graft lengths while preserving postoperative quality of life.

CLINICAL RELEVANCE

This study confirms the utility of 3D printing technology as an effective and precise tool in orthopedic surgery, particularly for complex reconstructions like large mandibular defects. It suggests a viable alternative that could potentially revolutionize current practices in bone grafting.

Meta-analysis of the survival rate and postoperative infection rate of primary and secondary implants after vascularized fibula transplantation for reconstruction of jaw defects

OBJECTIVES

Vascularized fibula flap transplantation is the most effective and common method to repair the jaw defects. In addition, implantation is the first choice to restore dentition on the graft fibula. Implants are usually implanted at least 6 months after fibula transplantation. Primary implantation of implants during surgery can restore the dentition earlier, but whether this method can achieve the same restorative effect as secondary implantation is still uncertain. This article aims to compare the survival rate and complications between primary and secondary implantation through meta-analysis.

METHODS

This meta-analysis was conducted according to PRISMA protocol and the Cochrane Handbook of Systematic Reviews of Interventions. According to the inclusion and exclusion criteria, we selected the PubMed, Embase, Web of Science, Cochrane Library, Chinese National Knowledge Infrastructure (CNKI), Chinese BioMedical Literature Database (CBM) according to established inclusion and exclusion criteria. The Newcastle-Ottawa Scale (NOS) was used to assess the quality of the included studies. Meta-analysis was conducted to compare the survival rate and postoperative infection rate of primary and secondary implantation.

RESULTS

Seven studies were involved in our research, involving 186 patients. Five of the studies detailed implant success in 106 patients (primary implantation 50, secondary implantation 56), and four studies documented infection after implantation in 117 patients (primary implantation 52, secondary implantation 65); the survival rate of the primary implantation was 93.3%, and the incidence of postoperative infection was 17.3%. The survival rate of the secondary implantation was 93.4%, and 23.1% had postoperative infection. Meta-analysis showed that there was no significant difference in the survival rate between primary implantation and secondary implantation, OR = 0.813 (95% CI 0.383-1.725, P = 0.589 > 0.05), and there was no significant difference in the incidence of postoperative infection, OR = 0.614 (95% CI 0.239-1.581, P = 0.312 > 0.05).

CONCLUSIONS

Based on the results of this study, the research found no significant difference in the survival rate or infection rates between primary and secondary implantation. After appropriate indications selection, primary implantation can be used to reconstruct the dentition with less waiting time, reduce the impact of radiotherapy, and bring a higher quality of life for patients.

Predictability of single versus double-barrel vascularized fibula flaps and dental implants in mandibular reconstructions: A systematic review and meta-analysis of prospective studies

STATEMENT OF PROBLEM

Patients with vascularized bone flaps from the fibula have reduced bone height, in which case a higher prosthetic abutment is needed for their implant-supported prosthesis. Although the double-flap technique seems promising, systematic reviews and meta-analyses of prospective studies are lacking.

PURPOSE

The purpose of this systematic review and meta-analysis was to evaluate the grafted areas of single barrel fibular flaps (SBFF) and double-barrel fibular flaps (DBFF) by considering failure rates, dental implant complications, and bone union at the osteotomy sites.

MATERIAL AND METHODS

A systematic review and meta-analysis was performed in accordance with the preferred reporting items for systematic reviews and meta-analyses (PRISMA) statement, population, intervention, control, and outcomes (PICO) question, and the National Health and Medical Research Council scales. The event rate of complications and failures was calculated with a confidence interval (CI) of 95%.

RESULTS

A total of 13 prospective studies with 441 participants and 330 graft sites were identified. A total of 235 participants had SBFF with 445 implants, and 95 had DBFF with 164 implants. The overall combined graft failure rates were 4.2% for SBFF and 3.2% for DBFF. The complication rate was 10% for SBFF and 1.9% for DBFF. Implant failure was at 4.7% in the SBFF group and 3.4% in the DBFF group.

CONCLUSIONS

Complication rates and implant failures were similar for SBFF and DBFF. Therefore, for long-term oral rehabilitation, both SBFF and DBFF are suitable procedures for mandibular reconstruction.

Autologous double barrel vascularized fibular bone graft for reconstruction after hemi resection of mandible due to ameloblastoma: Surgical case report

INTRODUCTION

Mandibular abnormalities caused by ameloblastoma present significant surgical and reconstructive difficulties. This study investigates double barrel fibular bone graft to correct these abnormalities and improve mandibular function and appearance.

CASE PRESENTATION

A 28-year-old male presented with a mandibular lump and facial asymmetry. The radiographic and histologic examination detected was subsequently diagnosed as ameloblastoma. After undergoing a hemi mandibulectomy procedure, a free vascularized fibular bone graft was harvested from the patient's left leg and transplanted to reconstruct the mandibular angle. The evaluation of the patient's functional outcomes was assessed utilising the University of Washington Quality of Life (UW-QOL) questionnaire. The patient UW - QOL Score has increased 62.5 pre-treatment to 93.75 post-treatment.

DISCUSSION

The suggested strategy to treating aggressive ameloblastomas is radical surgery, involving the use of wide resection and following bone reconstruction. Vascularized grafts, including the double-barrel fibular bone graft, are usually preferred in relation to mandibular defect reconstruction for their ability to offer improved stability, height, and thickness, which enhances functional results. In contrast to conventional approaches, our case did not show any signs of facial deformities or bone resorption. The utilization of the vascularized fibular bone graft proved to be a valuable option for early rehabilitation in patients with mandibular continuity defects, offering promising outcomes in terms of patient well-being and quality of life. This final result provides proof supporting the potential of this technique for managing mandibular defects.

CONCLUSION

Double-barrel fibular bone grafts and dental rehabilitation can restore mandibular continuity defect from ameloblastoma.

Microvascularized Fibular Bone Grafting for the Treatment of Mandibular Expansive Osseous Dysplasia - A Case Report

Rationale

Osseous dysplasia (OD) is a benign fibro-osseous lesion classified as periapical, focal or florid with some rare cases being diagnosed as expansive OD.

Patient Concerns

A 43-year-old female presented with gross mandible expansion and tooth displacement.

Diagnosis

Imaging scans revealed an expansive lesion in the anterior mandible, with varying opacity in the central region, and other smaller lesions in the region of teeth #37 and #47, consistent with expansive OD.

Treatment

Surgical resection followed by immediate reconstruction of the mandibular defect using a microvascularized fibular graft.

Outcomes

The patient had a 4-year follow-up, with adequate mandibular bone continuity, mastication, swallowing, and speaking ability reestablished.

Take-away Lessons

Immediate reconstruction after large surgical resection is required as tissues retract over time, hampering late reconstructions. Microvascularized fibular graft aims at adequate and functional rehabilitation with osseointegrated implants and long-term follow-up is needed as florid OD may evolve into expansive OD.

Rehabilitation of long-term mandibular defects by whole-process digital fibula flap combining with implants: A case report

Currently, the gold standard and workhorse in mandibular reconstruction is the free vascularized fibula flap. Particularly for patients who have had mandibulectomy for a long time, it is still difficult to precisely reconstruct the mandibular contour and successfully restore the patient's chewing function and esthetics. For the restoration and rehabilitation of long-term mandibular abnormalities, three-dimensional (3D) virtual surgical planning (VSP) and 3D-printed surgical guides are essential. Digital design and manufacturing were used to improve the accuracy of prostheses and facilitate occlusal reconstruction. Therefore, equipped with the methods of 3D VSP, 3D-printed surgical guides, free vascularized fibular flap, and immediate dental implants, this clinical report provides a feasible solution for mandibular reconstruction.

Application of a vascularized bone free flap and survival rate of dental implants after transplantation: A systematic review and meta-analysis

PURPOSE

As maxillofacial surgical techniques have advanced, vascularized bone free flap transplantation has become the standard treatment for repairing maxillofacial defects. In this meta-analysis, we summarize the survival rates of implants after VBFF surgery for maxillary and mandibular reconstructions and investigate the factors affecting patient outcomes.

METHODS

The PubMed, Embase, and Wanfang databases were searched up to May 31, 2022. The results of the treatment effect are presented as the risk ratio or odds ratio, using 95% confidence intervals. Statistical significance was calculated at α = 0.05 (two-tailed z tests).

RESULTS

35 studies were included in our analysis. The results revealed a 3-year and 5-year implant survival rate of 95.2% and 85.4% in VBFFs, respectively. The location of jaw defects (maxilla or mandible) or timing of implantation was not found to have a statistically significant influence on the survival rate. However, statistically significant differences were observed in the failure of implants placed in irradiated bone tissue.

CONCLUSIONS

Statistically significant differences were not found in the implant survival rate between simultaneous and delayed implantation, or between maxillary and mandibular defects. However, dental implants placed in irradiated flaps tended to have a lower survival rate than those surgically placed in non-irradiated flaps.

[Assessment of microhaemodynamics and oxygenation in tissues after the vestibuloplasty with the use of a free dermal autograft in patients after the reconstructive jaw surgery with the use of the revascularized autografts]

Purpose of the study: to study the features of microhaemodynamics and oxygenation in soft tissues in the area of the plastically reconstructed jaw after the vestibuloplasty.

MATERIALS AND METHODS

The study included 40 patients aged 20 to 65 (21 males and 19 females). The patients were divided into two groups: I group (14 patients) - patients after reconstructive surgery with the use a fibula autograft without the inclusion of a musculocutaneous «islet»; II group (26 patients) - patients after reconstructive surgery with the use a fibula autograft with the inclusion of a musculocutaneous «islet». To correct the prosthetic bed soft tissues, all patients underwent vestibuloplasty with the use of a free dermal autograft. To study microcirculation in tissues, the laser Doppler flowmetry (LDF) method was used. Microcirculation status was assessed by microcirculation index characterizing the level of tissue blood flow; parameter «σ,» which determines the oscillability of the flow of red blood cells and by coefficient of variation, characterizing vasomotor activity of microvessels. According to the Wavelet analysis of LDF-grams the blood flow bypass was determined. An oxygenation study was carried out in the tissues of the plastically restored jaw by optical tissue oximetry, the results of which determined the oxygenation index and the specific oxygen consumption index.

RESULTS

According to LDF data after vestibuloplasty, it was found that in I group, the microcirculation in soft tissues of the plastically reconstructed jaw restored in 21 days, and in II group in 2 months, which persisted at 6 months. In I group, the level of oxygenation and specific oxygen consumption normalized in 21 days, and in II group in 2 months, which persisted at 6 months.

CONCLUSION

Based on the results of this functional study, it was found that before vestibuloplasty microcirculation and oxygenation indices in II group patients were lower than those in I group patients. After vestibuloplasty with the use of a free dermal autograft, microcirculation indices in II group patients restored in 2 months, while in I group patients those indices restored in 21 days.

Deviation Analyses of Computer-Assisted, Template-Guided Mandibular Reconstruction With Combined Osteotomy and Reconstruction Pre-Shaped Plate Position Technology: A Comparative Study

Background

Computer-assisted and template-guided mandibular reconstruction provides higher accuracy and less variation than conventional freehand surgeries. The combined osteotomy and reconstruction pre-shaped plate position (CORPPP) technique is a reliable choice for mandibular reconstruction. This study aimed to evaluate the accuracy of CORPPP-guided fibular flap mandibular reconstruction and analyze the possible causes of the deviations.

Patients and Methods

From June 2015 to December 2016, 28 patients underwent fibular flap mandibular reconstruction. Virtual planning and personalized CORPPP-guided templates were applied in 15 patients while 13 patients received conventional freehand surgeries. Deviations during mandibulectomy and fibular osteotomy, and overall and triaxial deviation of the corresponding mandibular anatomical landmarks were measured by superimposing the pre- and postoperative virtual models.

Results

The deviation of the resection line and resection angle was 1.23 ± 0.98 mm and 4.11° ± 2.60°. The actual length of fibula segments was longer than the designed length in 7 cases (mean: 0.35 ± 0.32 mm) and shorter in 22 cases (mean: 1.53 ± 1.19 mm). In patients without ramus reconstruction, deviations of the ipsilateral condylar head point (Co.), gonion point (Go.), and coracoid process point (Cor.) were 6.71 ± 3.42 mm, 5.38 ± 1.71 mm, and 11.05 ± 3.24 mm in the freehand group and 1.73 ± 1.13 mm, 1.86 ± 0.96 mm, and 2.54 ± 0.50 mm in the CORPPP group, respectively, with significant statistical differences (p < 0.05). In patients with ramus reconstruction, deviations of ipsilateral Co. and Go. were 9.79 ± 4.74 mm vs. 3.57 ± 1.62 mm (p < 0.05), and 15.17 ± 6.53 mm vs. 4.36 ± 1.68 mm (p < 0.05) in the freehand group and CORPPP group, respectively.

Conclusion

Mandibular reconstructions employing virtual planning and personalized CORPPP-guided templates show significantly higher predictability, convenience, and accuracy of mandibular reconstruction compared with conventional freehand surgeries. However, more clinical cases were required for further dimensional deviation analysis. The application and exploration of clinical practice would also continuously improve the design of templates.

The deep circumflex iliac artery free flap in maxillofacial reconstruction: a comparative institutional analysis

PURPOSE

The aim of the present study was to perform a comparative analysis of the utility, outcomes, and complications of DCIA (deep circumflex iliac artery) flap for the reconstruction of maxillofacial defects between two institutions that continue to use the DCIA flap as a reconstructive resource.

MATERIALS AND METHODS

This retrospective analysis included a total of 68 patients (mean age 51.1 years) at the University Hospital of Parma, Parma, Italy, and the University of Maryland, Baltimore, USA, between January 2010 and April 2019.

RESULTS

No statistical differences were found in relation to the site of reconstruction (p = 0.09), bone graft quantity (p = 0.93), rehabilitation with dental implants (p = 0.464), length of hospitalization (p = 0.086), BMI (0.677), swallow function (p = 0.419), medical comorbidities (p = 0.933), pre-existing radiation (p = 0.691), adjuvant treatment (p = 0.298), ECOG-PS pre-and post-surgery (p = 0.329; p = 0.545), and flap failure: one partial failure observed (p = 0.412) and donor site morbidities (p = 0.742). A noted trend to increased risk of hernia without the use of a primary mesh repair was observed (p = 0.059).

CONCLUSION

The DCIA free flap represents a useful and reliable reconstructive flap for maxillofacial reconstruction. Reconstructive microvascular surgeons should be proficiently trained in this flap technique for its consideration as a first-line option in maxillofacial reconstruction.

Dental implant-based oral rehabilitation in patients reconstructed with free fibula flaps: Clinical study with a follow-up 3 to 6 years

BACKGROUND

Oral rehabilitation of patients after maxillofacial reconstructive surgery represents a challenge and stable prosthetic retention can be achieved with the use of dental implants.

PURPOSE

This retrospective report aimed to evaluate implant-based oral rehabilitation following maxillofacial reconstruction with free fibula flaps.

MATERIALS AND METHODS

A total of 14 patients who had reconstruction with fibula flaps either by CAD/CAM or conventional surgery were included in this study. A total of 56 implants (40 in flaps, 16 in native bone) were evaluated. Follow-up after reconstructive surgery ranged between 3.25 and 6.3 years. Follow-up after implant surgery ranged between 1.5 and 3.8 years.

RESULTS

Overall survival rate was 85.7% in free fibula flaps and 85.6% in dental implants. Eight implants were lost in three patients and all of these failures were in dental implants inserted in free flaps. According to the results on patient basis, the implant survival was not influenced by any variable.

CONCLUSIONS

The maxillofacial reconstruction with free fibula flap and oral rehabilitation with implant-supported prostheses after ablative surgery can be considered as an effective and safe procedure with successful aesthetic and functional outcomes.

Biomechanical Analysis of Various Reconstructive Methods for the Mandibular Body and Ramus Defect Using a Free Vascularized Fibula Flap

Several different methods exist for reconstructing the mandibular body and ramus defect with the use of a free vascularized fibula flap, but none have adequately addressed the long-term mechanical stability and osseointegration. The aim of this study is to compare the biomechanics of different surgical methods and to investigate the best approach for reconstructing the mandibular body and ramus defect. Five finite element models based on different reconstructive methods were simulated. Stress, strain, and displacement of connective bone sections were calculated for five models and compared. The models were printed using a 3D printer, and stiffness was measured using an electromechanical universal testing machine. The postoperative follow-up cone beam computed tomography (CBCT) was taken at different time points to analyze bone mineral density of connective bone sections. The results showed that the “double up” (DU) model was the most efficient for reconstructing a mandibular body and ramus defect by comparing the mechanical distribution of three sections under vertical and inclined loading conditions of 100 N. The stiffness detection showed that stiffness in the DU and “double down” (DD) models was higher compared with the “single up” (SU), “single down” (SD), and “distraction osteogenesis” (DO) models. We used the DU model for the surgery, and postoperative follow-up CBCT showed that bone mineral density of each fibular connective section increased gradually with time, plateauing at 12 weeks. We conclude that a free vascularized fibula flap of the DU type was the best approach for the reconstruction of the mandibular body and ramus defect. Preoperative finite element analysis and stiffness testing were shown to be very useful for maxillofacial reconstruction.

Functional Reconstruction of Mandibular Segment Defects With Individual Preformed Reconstruction Plate and Computed Tomographic Angiography-Aided Iliac Crest Flap

PURPOSE

With the development of imaging technology and computer-assisted surgery in oral and maxillofacial surgery, digital technology is widely used in vascularized bone flap grafts for mandibular reconstruction. The aim of this study was to use digital technology throughout the treatment process to show that digital techniques can provide a reliable and accurate match between the mandible and the iliac crest flap to achieve functional reconstruction of mandibular segment defects.

MATERIALS AND METHODS

Twenty patients underwent 3-dimensional (3D) computed tomography (CT), mirroring technology, 3D model prototyping, and CT angiography (CTA) for treatment planning. Individual preformed reconstruction plates were fabricated and iliac crest flaps were designed preoperatively. After complete resection of the mandibular lesion, the iliac crest flap was shaped to reconstruct the mandibular defects.

RESULTS

During follow-up (range, 12 to 36 months), the facial shape, facial symmetry, and mouth opening of all patients recovered well. The 3D CT reconstruction also was evaluated for height, width, length, and bone healing of the iliac crest flap. Postoperative examination showed ideal bone union between the iliac crest flap and the mandible at 6 months. Nine patients received implant-supported fixed dentures to restore dentition. After follow-up, all patients were satisfied with their facial esthetics and function. The new mandible provided a suitable 3D position for implant-supported fixed partial dentures.

CONCLUSION

Use of digital techniques throughout the course of treatment improves the predictability and convenience of functional mandibular reconstruction. Individual preformed reconstruction plates and CTA effectively guaranteed the accuracy of iliac flap preparation.