Zygomatic Implants Research Articles

Major indications and current clinical findings of zygomatic implant: a systematic review

Introduction: The lack of bone in the alveolar crest represents a major problem in aesthetic recovery in patients who have suffered dentoalveolar trauma, traumatic extractions, congenital tooth absence pathologies involving maxilla and mandible, and the possibility of deformity. In this sense, the zygomatic implant (ZI) is an alternative when there is bone loss. Objective: It was to carry out a systematic review of the main clinical outcomes of ZI, emphasizing the main indications. Methods: The present study followed the PRISMA rules. The search strategy was performed in the PubMed, Scielo, Cochrane Library, Web of Science and Scopus, and Google Scholar databases, following the rules of the word PICOS (Patient; Intervention; Control; Outcomes; Study Design). The Cochrane Instrument was used to assess the risk of bias of the included studies. Results and Conclusion: A total of 82 articles were found involving zygomatic implantation and the evolution of the technique. Initially, the duplication of articles was excluded. A total of 54 articles were fully evaluated and 33 were included in this study. Based on the clinical results of the last five years, some studies have broadened clinical understanding based on comparative studies to show the success rate of ZI. Even if more complications were reported for ZI that resolved spontaneously or could be handled, ZI proved to be a better modality of rehabilitation for severely atrophic jaws. Furthermore, zygomatic surgery proved to be a viable and safe alternative to conventional treatment modalities for oral rehabilitation of patients with ectodermal dysplasia syndrome. Also, there was greater accuracy and drastically reduced risk of perioperative/postoperative complications using the dynamic navigation system compared to the freehand placement of implants. Finally, guided surgery for the placement of ZI using specially designed metal jigs that must be supported by bone showed the placement of a made-to-measure provisional prosthesis, reducing surgery time, simplifying the procedure, and optimizing the result.

Peri-zygomatic infection associated with zygomatic implants: Aretrospective longitudinal cohort study.

The main objective of this retrospective, longitudinal, cohort study was to describe the occurrence of peri-zygomatic infection (PZI) as a complication associated with zygomatic implant (ZI) placement in a period of 22years. A retrospective search was carried out in the department of oral and maxillofacial surgery of Saint John's hospital in Genk, Belgium. Patients that had a severely atrophic fully or partially edentulous maxilla, and at least one ZI placed, were included. A total of 302 eligible patients, underwent ZI surgery between 1998 and 2020. From a total of 940 ZI, 45 were associated with the development of PZI. PZI was located in the upper portion of the cheek in relation to the external corner of the eye, one or two centimeters under the lower lid. The total number of affected patients was 25 (8.3%), who had a mean age of 58.1years. In this subset, PZI occurred in 15 cases on the right side, in eight cases on the left side, and in two cases bilaterally. Ultimately, 16 ZI were lost in the PZI site. The mean time since the implant placement to the diagnosis of PZI was 1.9years (SD ±2.4) and to the ZI removal of 3.8years (SD ±3.7). After implant removal, the PZI symptomatology dissipated in all patients. Peri-zygomatic infection should be informed to the patients as a possible complication after ZI placement. Once identified, it should be acknowledged as a risk factor for ZI failure.

Reliability and accuracy of dynamic navigation for zygomatic implant placement.

ObjectivesTo assess the accuracy of a real‐time dynamic navigation system applied in zygomatic implant (ZI) surgery and summarize device‐related negative events and their management.Material and methodsPatients who presented with severely maxillary atrophy or maxillary defects and received dynamic navigation‐supported ZI surgery were included. The deviations of entry, exit, and angle were measured after image data fusion. A linear mixed‐effects model was used. Statistical significance was defined as p < .05. Device‐related negative events and their management were also recorded and analyzed.ResultsTwo hundred and thirty‐one zygomatic implants (ZIs) with navigation‐guided placement were planned in 74 consecutive patients between Jan 2015 and Aug 2020. Among them, 71 patients with 221 ZIs received navigation‐guided surgery finally. The deviations in entry, exit, and angle were 1.57 ± 0.71 mm, 2.1 ± 0.94 mm and 2.68 ± 1.25 degrees, respectively. Significant differences were found in entry and exit deviation according to the number of ZIs in the zygomata (p = .03 and .00, respectively). Patients with atrophic maxillary or maxillary defects showed a significant difference in exit deviation (p = .01). A total of 28 device‐related negative events occurred, and one resulted in 2 ZI failures due to implant malposition. The overall survival rate of ZIs was 98.64%, and the mean follow‐up time was 24.11 months (Standard Deviation [SD]: 12.62).ConclusionsThe navigation‐supported ZI implantation is an accurate and reliable surgical approach. However, relevant technical negative events in the navigation process are worthy of attention.

Retrospective analysis of the predictability of using three-dimensional models for preoperative planning of the length of zygomatic implants.

This present study aimed to retrospectively evaluate the predictability of using three-dimensional models (TDMs) to plan the preoperative lengths of zygomatic implants (ZIs). The records of all patients that received such implants between March 2007 and March 2019 were evaluated. The ZI lengths predicted on the TDMs were compared to the lengths of the implants the patients received. In total, the records of 74 patients were evaluated, of which 37 records met the criteria of inclusion, and were included in the study. Twenty-seven (73%) of the patients were female and 10 (27%) were male, ranging from 34 to80 years of age, with the average age being 55.7 years. Seventeen (43.2%) of these patients were classified as ASA I and 21 (56.8%) as ASA II. A total of 142 ZIs were planned and installed in the time frame mentioned. Without distinguishing the region of the maxilla, the implants used were, on average, 1.1 mm larger in length than those initially planned. Overall, the data indicates moderate agreement between the planned and surgical lengths of the ZIs and indicates that using TDMs is a predictable and reliable preoperative planning technique of the length of posterior ZIs.

Changing trends in the microvascular reconstruction and oral rehabilitation following maxillary cancer

PurposeThe maxillectomy defect is complex and the best means to achieve optimal reconstruction, and dental rehabilitation is a source of debate. The refinements in zygomatic implant techniques have altered the means and speed by which rehabilitation can be achieved and has also influenced the choice regarding ideal flap reconstruction. The aim of this study is to report on how the method of reconstruction and oral rehabilitation of the maxilla has changed since 1994 in our Institution, and to reflect on case mix and survival.MethodsConsecutive head and neck oncology cases involving maxillary resections over a 27-year period between January 1994 and November 2020 were identified from hospital records and previous studies. Case note review focussed on clinical characteristics, reconstruction, prosthetic rehabilitation, and survival.ResultsThere were 186 patients and the tumour sites were: alveolus for 56% (104), hard palate for 19% (35), maxillary sinus for 18% (34) and nasal for 7% (13). 52% (97) were Brown class 2 defects. Forty-five patients were managed by obturation and 78% (142/183) had free tissue transfer. The main flaps used were radial (52), anterolateral thigh (27), DCIA (22), scapula (13) and fibula (11). There were significant changes over time regarding reconstruction type, use of primary implants, type of dental restoration, and length of hospital stay. Overall survival after 24 months was 64% (SE 4%) and after 60 months was 42% (SE 4%).ConclusionThese data reflect a shift in the reconstruction of the maxillary defect afforded by the utilisation of zygomatic implants.

Meet the Founding Resident Ambassador: John M. Le, DDS, MD

We are happy to continue adopting the best global publishing experience and traditions into the new year of 2022. To start off, we are honored to adopt the progressive tradition held by Plastic and Reconstructive Surgery (PRS) journal. As a phenomenal journal with more than 75 years of publishing developments, PRS serves as a trailblazer for the Journal of Diagnostics and Treatment of Oral and Maxillofacial Pathology. The PRS Editorial Board founded the Resident Ambassador position in 2014 after an unofficial Resident Advisory Board (RAB) meeting of four residents at the 2013 Annual Meeting.2 And now after 7 years, the PRS and PRS Global RAB includes more than 70 members across the world with six PRS and PRS Global Open Resident Ambassadors.2 The RAB serves both PRS and their daughter journal – Plastic and Reconstructive Surgery Global Open (PRS Global Open). The key missions for the members of the RAB are to participate in three of five activities: (1) the PRS journal club on Facebook, (2) the PRS Grand Rounds (a multipronged and multitopic live lectures with question-and-answer series)2 via Facebook, (3) creation of PRS promoting videos on their own social media pages, (4) supporting PRS and PRS Global Open as a peer-reviewers, and (5) voting on the journal’s social media pages. The search for a true leader to take on the role as the Founding Resident Ambassador for the Journal of Diagnostics and Treatment of Oral and Maxillofacial Pathology was an uneasy task. After an extensive search, we are honored to start a collaboration with an oral and maxillofacial surgery (OMS) resident from the state of Alabama in the United States of America. John M. Le, DDS, MD and his colleagues in the Department of Oral and Maxillofacial Surgery at the University of Alabama at Birmingham have made a serious impact on global oral and maxillofacial surgery specialty. Moreover, their article contribution to our journal in 2020 made a huge influence by attracting an international community of readers to our journal, making us enormously proud. The masterpiece was dedicated to the use of zygomatic implants for restoration of complex nasal defects. Thereby, the current academic achievements and research activities of Dr. Le serves as a model for other OMS residents in training. In general, his clinical interests include, but is not limited to head, neck and oral oncology and reconstructive surgery.

Maxillary Sinusitis as a Complication of Zygomatic Implants Placement: A Narrative Review

Aims: The aim of this review is to consider maxillary sinusitis as a complication of zygomatic implants placements. Maxillary sinusitis a common complication but in the literature there are no reviews that focus only on this condition and its possible treatment. This review was carried out with to highlight the main findings of the literature on this topic and to improve knowledge in this field. Methods: The search strategy resulted in 155 papers. After selection of the inclusion criteria only 11 papers were examined. From the papers these, 12.3% patients presented maxillary sinusitis but only four studies evaluated sinusitis (both clinical and radiological evaluation). The most common treatment used by the authors were antibiotics alone or combined with functional endoscopic sinus surgery (FESS). Results: The literature shows an absence of precise and shared guidelines diagnosis and post-operative follow-up, and of the treatment of maxillary sinusitis following zygomatic implantology. It has not been determined if the surgical placement of ZIs is better than the other techniques for treatment of the onset of maxillary sinusitis in the post-operative period. Conclusion: To date there are no shared protocols for maxillary sinusitis treatment. In our experience, and according to the literature in the presence of risk factors such as age, comorbidities, smoking, nasal septal deviation or other anatomical variants, we suggested that FESS is performed at the same time as placement of zygomatic implants.

COMPLICATIONS OF ZYGOMATIC IMPLANTS: A REVIEW OF SCIENTIFIC EVIDENCE

Background: Despite the technological advances the zygomatic implants (ZI) and its proven success, this rehabilitation option is sensitive, not a routine in dental practice, requiring technical mastery, surgical experience, and in-depth anatomical knowledge, which makes it quite susceptible to complications. In addition, little is discussed about these disorders, whether immediate or late, although they are essential knowledge for the surgeons who perform this procedure. Aim: The objective of the study was to answer the question through literature review: "Are there surgical complications in zygomatic implants?" As well as to argue the main intercurrences found. Material and Methods: The review of the literature was conducted on PubMed/Medline, Cochrane and SciELO using the descriptors: “Complications” or “Failure” and “Zygomatic Implants”. The included articles were observational studies that related ZI and complications. The initial research identified 448 articles, but 42 of them that mentioned complications associated with ZI were considered in this study. Results: The most common complication is sinusitis followed by peri-implantitis, problems with the prosthetic connection, fistula towards the implant, paresthesia, hematoma, lip laceration, ecchymosis, penetration of the orbital cavity, aspergillosis, intracranial penetration, and intraorbital hemorrhage. 44 out of 2835 ZIs placed in immediate or late loading were lost (1.5%). There were 223 minor or major complications in the 2827 implants (7.86%). Conclusions: The low morbidity of this treatment for maxillary atrophy, there are some immediate and late complications to be considered in the choice of rehabilitation treatment and that these should be reported preoperatively to the patients.

Finding Better Ways to Perform Graftless Full Rehabilitation of a Compromised Maxilla: New Platform-Switched Zygomatic Implants Placed Extra-Sinus Improve Prosthetic Restoration—A Preliminary Study of 25 Cases and 85 Implants

Standard treatment for full rehabilitation of compromised maxillae with regular implants includes sinus elevation grafting, a minimum of two to three surgeries, and a minimum treatment time of 9 to 15 months. Zygomatic implants are a viable alternative. However, prosthetic restorations have been compromised due to abutments emerging on the palate. The purpose of this study was to find ways that abutments will emerge on the ridge (occlusal surface). The presented results show it can be done if zygomatic implants are placed in the sinus wall (extra-sinus) and use an internal, conical connection with platform-switching and 45-degree abutments. Thus, marginal tissue prognosis and primary stability may also be improved by adding coronal threads to an implant design. These improvements, if confirmed in longer follow-ups and further studies, may encourage more graftless rehabilitations of severely compromised maxillae, reducing the number of surgeries and overall treatment time.

Possibilities and effectiveness of dental rehabilitation using dental and zygomatic implants

Possibilities and effectiveness of dental rehabilitation using dental and zygomatic implants

A novel guided zygomatic implant surgery system compared to free hand: A human cadaver study on accuracy

Objectives: The aim of this human cadaver study was to compare the accuracy of guided versus free-hand zygomatic implant placement. For the guided implant placement laser sintered titanium templates were used.Methods: Forty zygomatic implants were placed in ten cadavers heads. For each case two implants were inserted using the guided protocol (Ezgoma guide, Noris Medical, Israel) and the related surgical kit and the other two by using a free hand approach. Post-operative computed tomography (CT) scans were carried out to assess the deviations between planned and inserted implants. The accuracy was measured by overlaying the post-operative CT scan (with the final position of the achieved implants) with the pre-operative CT scan (with the planned implants).Results: The difference of the mean between planned and placed zygomatic implants by using surgical guides or free hand were statistically significant for all the variables evaluated: angular deviation (1.19°±0.40° and 4.92°±1.71°, p<0.001), linear distance deviation at coronal point (0.88 mm±0.33 mm and 2.04 mm±0.56 mm, p<0.001), at apical point (0.79 mm±0.23 mm and 3.23 mm±1.43 mm, p<0.001) and at apical depth (0.35 mm±0.25 mm and 1.02 mm±0.61 mm, p<0.001).Conclusions: The proposed guided surgery system exhibited a higher accuracy for all the investigated variables, when compared to the free hand technique.

Rehabilitation of Atrophic Maxilla With Immediate Loading of Extrasinus Zygomatic Implant.

The aim of this case series was to evaluate the long-term success rate of immediate occlusal loading of extrasinus zygomatic dental implants after a 3-year follow-up. The sample consisted of 31 patients (mean age of 64 years) with atrophic maxillae rehabilitated with 1 to 4 extrasinus zygomatic implants, placed unilaterally or bilaterally. All the patients received complete implant-supported dental prostheses with immediate loading by associating zygomatic implants with conventional implants. None of the procedures were associated with bone grafts. During the 3-year period of follow-up in the present study, all the patients attended clinical sessions and underwent radiographic exams every 6 months. In total 55 zygomatic and 69 conventional implants were placed, where 1 zygomatic and 2 conventional implants were lost, representing success rates of 98.18% and 97.20%, respectively. None of the studied patients had signs of sinusitis or changes in the maxillary sinuses. All the patients showed occlusal contact on natural antagonist teeth or implant-supported dental prostheses. Therefore, it was concluded that the use of exteriorized zygomatic implants with immediate loading represented a feasible option with high success rates for the treatment of atrophic maxilla.

Survival rates of dental implants in patients with head and neck pathologies: 12-year single-operator study

To evaluate the survival rates of dental implants placed in patients with head and neck pathologies treated with resective surgery with or without free flap reconstruction, radiotherapy alone, and/or chemotherapy. In this study, we retrospectively analyzed the survival of intraoral dental implants placed by the same surgeon over a 12-year period from 2007 to 2019. These implants were followed up clinically and radiographically for a period of 36 months postoperatively and throughout the restorative phase. A total of 190 patients with a total of 739 dental implants, comprising both intraoral and zygomatic implants, were included in this study. Overall, the dental implant survival rate was 95%, with a similar rate for dental implants placed in irradiated and nonirradiated bone (90% vs 93%). A lower implant survival rate was noted in implants placed in transplanted bone (79%). In cases of implant failure (n=17), 35% (n=6) of protheses survived and remained functional. Our findings support the placement of dental implants in patients with benign and malignant pathologies of the head and neck to improve their quality of life. However, we highlight the need for careful surgical planning and placement by experienced clinicians.

Managing the severely atrophic maxilla: Farewell to zygomatic implants and extensive augmentations?

Background: Dental rehabilitation of severe atrophic upper jaws remains challenging. A new generation of subperiosteally placed and rigid multi-vector bone-anchored patient-specific implants proposes an innovative line extension in implant dentistry. This single-center retrospective study focused on treating severely atrophic maxillae using these implants.Methods: All patients who were treated with a patient-specific implant (IPS Implant® Preprosthetic, KLS-Martin, Tuttlingen, Germany) at Hannover Medical School due to severe atrophy of the maxilla who had no history of malignancy, cleft lip or palate, or trauma were evaluated regarding implant stability and prosthetic restoration, as well as complications.Results: Out of a total of 58 inserted implants, 13 implants in 10 patients, which were placed to treat a severely atrophic upper jaw, were identified. The mean follow-up period was 8.2 months (1–29 months). All implants were clinically stable over the entire period. All patients with an observation period of over 2 months received prosthetics for restoration. Minor complications, screw fractures, infection, and exposure of the framework were observed, but these did not lead to failure.Conclusion: This initial follow-up suggests that this new generation of implants represents a valuable treatment alternative, especially for patients with a history of failed dental implant placement. Larger numbers of cases and longer observation periods are required to confirm our findings.

Retrospective Analysis of Clinical and Radiologic Data Regarding Zygomatic Implant Rehabilitation with a Long-Term Follow-Up.

Background: Zygomatic implants have been introduced to rehabilitate edentulous patients with severely atrophic maxillae. Their use has been reported by several studies, describing high overall survival rates at medium–long follow-up. The aim of this study was to retrospectively analyze if a few patient-related and implant-related features are correlated with implant success or the onset of complications. Materials and methods: Data of patients treated with zygomatic implants between May 2005 and November 2012 at three private clinics were collected and retrospectively analyzed. For each implant, the following data were collected: implant length, insertion path, ridge atrophy and sinus characteristics (width, pneumatization, thickness of mucosae, patency of sinus ostium). General patient characteristics and health status data were also recorded. The outcomes evaluated were implant failure, infective complications, early neurologic complications and overall complications. Results: A total of 33 patients (14 men, 17 women, mean age 59.1) that received 67 zygomatic implants were included in the study. The mean duration of the follow-up was of 141.6 months (min 109; max 198). In this period, a total of 16 (23.88%) implants in 8 (24.24%) patients were removed and 17 (51.51%) patients with 36 (53.73%) implants reported complications. Immediate loading resulted in a significantly lower risk of complications compared with the two-stage prosthetic rehabilitation (OR: 0.04, p = 0.002). A thickness of the sinus mucosa > 3 mm emerged to be correlated with a greater occurrence of infective complications (OR: 3.39, p = 0.019). Severe and extreme pneumatization of the sinus was significantly correlated with the incidence of overall complications (p = 0.037) and implant failure (p = 0.044). A large sinus width was predisposed to a higher risk of neurologic complications, infective complications and implant failure (p = 0.036, p = 0.032, p = 0.04, respectively). Conclusions: zygomatic implants are an alternative procedure for atrophic ridge rehabilitation when a conventional implant placement is not possible. Several clinical and anatomical factors can have a significant role in complication occurrence.

Simultaneous Le Fort I osteotomy and zygomatic implant placement

The aim of this retrospective study was to evaluate the outcomes of simultaneous LeFort I osteotomy and zygomatic/dental implant placement for oral rehabilitation of patients with extremely atrophic/dysmorphic edentulous maxilla.Simultaneous LeFort I osteotomy and zygomatic/dental implant placement was performed with patient-specific anatomical models and surgical guides produced through three-dimensional virtual planning methods. All patients received their final prosthesis, with immediate loading, on the day after surgery. The primary outcome variables were the implant survival rate, and the incidence of intra/postoperative complications. In total, 15 zygomatic implants and 33 conventional dental implants were inserted in eight patients. The mean follow-up of the patients was 38.5 months. The implant survival rate was 93.3% for zygomatic implants and 100% for dental implants. No intra/postoperative complications were observed.Simultaneous LeFort I osteotomy associated with zygomatic/dental implant surgery can be considered as a valuable treatment option for rehabilitation of patients with extremely atrophic edentulous maxilla and esthetic issues of the face.

EAO‐299/PO‐SU‐027 | Two‐year follow‐up of zygomatic implants for the rehabilitation of the atrophic maxilla

EAO‐299/PO‐SU‐027 | Two‐year follow‐up of zygomatic implants for the rehabilitation of the atrophic maxilla

The Zygomatic Implant Perforated (ZIP) flap reconstructive technique for the management of low-level maxillary malignancy - clinical & patient related outcomes on 35 consecutively treated patients.

The zygomatic implant perforated (ZIP) flap technique provides immediate reconstruction and rapid dental rehabilitation for low-level malignant tumors. Patients who underwent ZIP flap reconstruction between December 2015 and February 2021 were followed prospectively. Thirty-five consecutively treated patients were studied with 16 undergoing surgery alone and 19 undergoing surgery followed by radiotherapy. The median time to fit the prosthesis was 29 days with all patients requiring adjuvant radiotherapy receiving their fixed dental prosthesis prior to its commencement. Vascularized flap (100%), zygomatic implant (98.4%), and prosthesis (97%) survival were excellent and the ZIP flap protocol was highly rated by patient-related outcome measures especially for the chewing domain. The ZIP flap technique provides an excellent means of providing an autogenous oronasal seal and a foundation for immediate cortically anchored fixed dental rehabilitation. This technique provides rapid and robust rehabilitation for patients presenting with low-level maxillary malignancy despite the use of radiotherapy.

"Three-Dimensional Ring" of Zygomatic-Supported Prosthetics Rehabilitation in Bilateral Maxillary Defect.

Patients with maxillary defects after a maxillectomy live with a range of functional and social problems. As techniques for functional reconstruction of the maxilla have been applied in a number of these patients, some of them regained confidence in their lives again. Nevertheless, there was still no clear consensus on the connecting and loading patterns of zygomatic implant-supported prosthetics in bilateral maxillary defects. This study aimed to investigate the function of a novel technique using "three-dimensional ring"-supported prosthetics based on zygomatic implants and compared its effects with two other conventional approaches through assessing the quality of the patient's life. Forty-five eligible patients who had different degrees of maxillectomy received treatment of conventional prostheses with a clasp (25 patients, group 1), a regular implant with obturator removal (10 patients, group 2), or a zygomatic implant combined with "three-dimensional ring"-supported prosthetics (10 patients, group 3). A questionnaire that included the indicators of the Obturator Functioning Scale (OFS) and EORTC Head and Neck 35 assessment was employed to evaluate the functional rehabilitation and quality of life (QOL) of patients in the study. The data were then summarized into a worksheet (Excel 2010), and the mean and standard deviation were calculated. The data were processed with SPSS 19.0 for Windows statistical software. The questionnaire analysis showed a statistically significant difference in the OFS, EORTC H&N 35, and QOL scores between group 3 and group 1 or group 2. Importantly, in the assessment of EORTC H&N 35, the proportion of patients in group 3 who lost weight after the functional restoration of maxillary defection was lower than that of the other two groups. In this research, a new connection device mode, which provided a retentive force between the zygomatic implants and prosthetics through a 3D ring-shaped milling bar with golden galvanized frames, was conducted and proved to be a reliable and feasible functional reconstruction therapy through patients' questionnaire surveys. This research provided an effective reconstruction strategy for patients with maxillary resection that could remarkably improve the life quality of patients.

Real-Time Dynamic Navigation System for the Precise Quad-Zygomatic Implant Placement in a Patient with a Severely Atrophic Maxilla.

Zygomatic implants (ZIs) are an ideal way to address cases of a severely atrophic edentulous maxilla and maxilla defects because they replace extensive bone augmentation and shorten the treatment cycle. However, there are risks associated with the placement of ZIs, such as penetration of the orbital cavity or infra-temporal fossa. Furthermore, the placement of multiple ZIs makes this surgery risky and more difficult to perform. Potential intraoperative complications are extremely dangerous and may cause irreparable losses. Here, we describe a practical, feasible, and reproducible protocol for a real-time surgical navigation system for precisely placing quad-zygomatic implants in the severely atrophic maxilla of patients with residual bone that does not meet the requirements of conventional implants. Hundreds of patients have received ZIs at our department based on this protocol. The clinical outcomes have been satisfactory, the intraoperative and postoperative complications have been low, and the accuracy indicated by infusion of the designed image and postoperative three-dimensional image has been high. This method should be utilized during the entire surgical procedure to ensure ZI placement safety.