Quantitative assessment of symmetry recovery in navigation-assisted surgical reduction of zygomaticomaxillary complex fractures

Efficacy of Two-Point Versus Three-Point Fixation for Zygomaticomaxillary Fractures: A Systematic Review and Meta-analysis

Background

The zygomaticomaxillary complex (ZMC) functions as the main buttress for the lateral portion of the middle third of the facial skeleton and because of its prominent position & convex shape, it is frequently fractured, alone or along with other bones of the midface. The management of the ZMC fractures is debatable as the literature is saturated with various theories. A number of techniques, from closed reduction to open reduction and internal fixation can be effectively used to manage these fractures. Controversies lie right from the amount of fixation (mostly 2-, 3-point fixation) required to the ideal approach, and there is no conclusive view on its ideal line of management.

Aim

To systematically review the existing scientific literature to determine whether two-point or three-point fixation is a better treatment alternative for the patients with zygomaticomaxillary fractures through a meta-analysis.

Methods

Review was performed in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Electronic databases like PubMed, Google scholar and Ebsco Host were searched from January 2000 to November 2023 for studies reporting treatment of zygomaticomaxillary fractures through two-point and three-point fixation and reporting the outcome in terms of mean and standard deviation (SD). Quality assessment of included was evaluated using Cochrane risk of bias (ROB)-2 tool through its domains. The risk of bias summary graph and risk of bias summary applicability concern was plotted using RevMan software version 5.3. The standardized mean difference (SDM) was used as summary statistic measure with random effect model and p value < 0.05 as statistically significant.

Results

Eleven studies fulfilled the eligibility criteria and were included in qualitative synthesis, of which only eight studies were suitable for meta-analysis. The pooled estimate through the standardized mean difference (SMD) of - 0.21 (- 0.83-0.41) favors two-point fixation employing random effect model with I2 (heterogeneity) value of 89% and p value 0.51. Publication bias through the funnel plot showed asymmetric distribution with systematic heterogeneity.

Conclusion

In our systematic review, we aimed to evaluate which method of fixation is more effective in the treatment of zygomaticomaxillary complex fractures. Our pooled estimate using quantitative synthesis indicates that both two- and three-point fixation procedures are equally effective in the treatment of zygomaticomaxillary fractures. As a result, two-point fixation is as efficient as three-point fixation in treating zygomaticomaxillary complex fractures.

Enhancing Surgical Approach: Breakthrough Markerless Surface Registration With Augmented Reality for Zygomatic Complex Fracture Surgeries

BACKGROUND

Innovative technologies with surgical navigation have been used for enhancing surgical accuracies for zygomaticomaxillary complex (ZMC) fractures and offers advantages in precision, accuracy, effectiveness, predictability, and symmetry improvement. Moreover, augmented reality (AR) navigation technology combines virtual reality, 3-dimensional (3D) reconstruction, and real-time interaction, making it ideal for bone tissue operations. Our study explored the usefulness and clinical efficacy of AR technology in intraoperative guidance for reducing ZMC fractures.

METHODS

We retrospectively studied 35 patients with zygomatic complex fractures, comparing outcomes of AR-guided and conventional methods. Furthermore, the AR system provided real-time visualization and guidance. The evaluation included reduction accuracy using root mean square (RMS) value and symmetry analysis using a mirror image of 3D models. Results demonstrated the feasibility and effectiveness of the AR-guided method in improving outcomes and patient satisfaction.

RESULTS

In 35 patients (25 males, 10 females), AR-guided (n = 19) and conventional (n = 16) approaches were compared. Age, sex, and fracture type exhibited no significant differences between groups. No complications occurred, and postoperative RMS error significantly decreased ( P < 0.001). The AR group had a lower postoperative RMS error ( P = 0.034).

CONCLUSIONS

Augmented reality-guided surgery improved accuracy and outcomes in zygomatic complex fractures. Real-time visualization enhanced precision during reduction and fixation. This innovative approach promises enhanced surgical accuracy and patient outcomes in craniofacial surgery.

Maxillary sinus volume and facial asymmetry after unilateral zygomaticomaxillary complex fracture reduction with 2, 3, and 4 fixation points: CBCT-based investigation

PURPOSE

This study aimed to assess the maxillary sinus volume (MSV), Chronic Sinusitis incidence, and asymmetry of the zygomaticomaxillary complex (ZMC) following ZMC fracture surgery with various numbers of fixation points.

MATERIALS AND METHODS

In a prospective non-randomized cohort, 50 adults with unilateral ZMC fractures who treated by open reduction and internal fixation (ORIF) between November 2019 and October 2021 were assigned to accomplish this study. They distributed into three groups as per fixation points (2, 3, or 4 Points). Preoperative (T1), Immediate postoperative (T2), and follow-up (T3) cone beam computed topography were analyzed using the Mimics software. The main measures were MSV and asymmetry indexes (ASI) of six paired bilateral anatomical landmarks (Orbital, Suprajugal, Jugale, Zygon, Maxillozygion 1, and Maxillozygion 2).

RESULTS

MSV decreased significantly on the affected sides postoperatively in 2P and 3P groups, both in T2 and T3. Further, the T2-T3 comparisons showed a significant MSV change (p = 0.001). ASI reduced considerably to clinically tolerated levels (<3 mm) on landmarks near the fixation sites postoperatively. The ASI on the Zygon and Maxillozygion 1 landmarks showed significant changes among the three groups in both T2 and T3. Interestingly, only five cases had reported postoperative sinusitis symptoms.

CONCLUSIONS

Although the MSV was changed among the different fixation point groups, the incidence of chronic sinusitis was uncommon. Bilateral asymmetry affected by number and position of the fixation points, fixation with 4 points provide more symmetry.

Accuracy of surgical navigation for patient-specific reconstructions of orbital fractures: A systematic review and meta-analysis

OBJECTIVE

This systematic review and meta-analysis aimed to review the recent literature on the technical accuracy of surgical navigation for patient-specific reconstruction of orbital fractures using a patient-specific implant, and to compare surgical navigation with conventional techniques.

MATERIALS AND METHODS

A systematic literature search was conducted in PubMed (Medline), Embase, Web of Science, and Cochrane (Core Collection) databases on May 16, 2023. Literature comparing surgical navigation with a conventional method using postoperative three-dimensional computed tomography imaging was collected. Only articles that studied at least one of the following outcomes were included: technical accuracy (angular accuracy, linear accuracy, volumetric accuracy, and degree of enophthalmos), preoperative and perioperative times, need for revision, complications, and total cost of the intervention. MINORS criteria were used to evaluate the quality of the articles.

RESULTS

After screening 3733 articles, 696 patients from 27 studies were included. A meta-analysis was conducted to evaluate volumetric accuracy and revision rates. Meta-analysis proved a significant better volumetric accuracy (0.93 cm3 ± 0.47 cm3) when surgical navigation was used compared with conventional surgery (2.17 cm3 ± 1.35 cm3). No meta-analysis of linear accuracy, angular accuracy, or enophthalmos was possible due to methodological heterogeneity. Surgical navigation had a revision rate of 4.9%, which was significantly lower than that of the conventional surgery (17%). Costs were increased when surgical navigation was used.

CONCLUSION

Studies with higher MINORS scores demonstrated enhanced volumetric precision compared with traditional approaches. Surgical navigation has proven effective in reducing revision rates compared to conventional approaches, despite increased costs.

Symmetry recovery in zygomaticomaxillary complex fractures compared to normal unfractured population: A new reliable 3D evaluation

OBJECTIVE

This study aims to quantify the facial symmetry of surgically treated zygomaticomaxillary complex (ZMC) fractures through a new reliable three-dimensional evaluation method, which is crucial for improving post-operative aesthetic and functional outcomes.

MATERIAL AND METHODS

Healthy patients and patients with surgically treated ZMC fractures were retrospectively reviewed. Using Brainlab Elements® the zygomatic bone and the orbit of each patient was segmented and mirrored. Subsequently, the mirrored side was matched with the other side via volume-based registration, using the segmented orbit as reference. Volumetric asymmetry was measured using 3-matic software, and a surface-based matching technique was used to calculate the mean absolute differences (MAD) between the surfaces of the two sides of the ZMC. The reliability of this novel method using volume-based registration was tested, and the intra-class correlation coefficient was assessed.

RESULTS

The MAD between the surfaces of the left and right sides in the control group was 0.51 mm (±0.09). As for the ZMC fracture group, MAD was 0.78 mm (±0.20) and 0.72 mm (±0.15) pre- and post-operatively, respectively. The MAD showed statistically significant differences between pre- and post-operative groups (p = 0.005) and between control and post-operative groups (p < 0.001). The intra-class correlation coefficient was high (≥0.99).

CONCLUSIONS

This evaluation method using mirroring and volume-based registration to determine the symmetrical position of the ZMC is reliable. The surface-based measurements revealed an improved symmetry after surgery. However, the symmetry of the treated patients remained lower than the control group.

Evaluation of the Relationship Between Zygomatic Arch Fracture Reduction and Mandibular Movements

Objective

The aim of this study was to evaluate the relationship between surgical zygomatic arch fracture reduction and mandibular movements in different fracture types.

Materials and Methods

Fractures were classified according to the Yamamoto classification. The extent of zygomatic arch reduction after surgery was evaluated by measuring three reference points on both fractured and normal side both before and after surgery. The selected reference points were: the most anterior (A1), the most posterior (B1) and the midpoint (C1) relative to midsagittal plane on the fracture side and the same points on the normal side (a1, b1, c1). Mouth opening, movements to right and left were recorded in these patients.

Results

The highest extent of zygomatic arch reduction was observed at the midpoint of the arch (p = 0.041). Surgery did not significantly alter other points of the zygomatic arch. The extent of reduction of the zygomatic arch was not significantly associated with mandibular movements. However, type of fracture correlated with lateral excursion to the right and left (p = 0.002 and p = 0.031, respectively).

Conclusion

This study showed that the amount of post-surgical changes in zygomatic arch reduction was not significantly related to mandibular movements. In addition, the amount of lateral excursion two weeks after surgical correction of more severe types of zygomatic arch fractures was less compared with other fracture types. Patients with more severe fractures may need to be followed for a longer period of time in order to regain the normal mandibular movement range.

Changes in Facial Symmetry Following Computer-Assisted Secondary Correction of Craniofacial Fractures

OBJECTIVE

For patients without dysfunctions, the main purpose of secondary correction for craniofacial fractures is restoring facial symmetry. Computer-assisted surgery techniques including virtual surgical planning and intraoperative navigation provide the help to restore the bony symmetry as much as possible. The authors retrospectively quantitatively analyzed patients who received computer-assisted secondary correction for craniofacial fractures on facial symmetry pre and postoperation.

METHODS

This observational study reviewed the medical records of 17 patients requiring secondary correction for craniofacial fractures. Pre and postoperative computed tomography data were used to quantitatively analyze the changes in facial symmetry and enophthalmos.

RESULT

All patients enrolled in this study showed mid-facial asymmetry but without dysfunctions except for enophthalmos, and 5 patients had bone defects in the frontal-temporal area. The corrective surgical techniques were different for each patient according to their specific condition. Virtual surgical planning with or without intraoperative navigation was performed for all patients. Compared with the preoperative condition, their facial symmetry was significantly improved. The maximum discrepancy value between the affected side and the mirrored unaffected side decreased from 8.10 ± 2.69 to 3.74 ± 2.02 mm postoperatively, and the mean discrepancy value decreased from 3.58 ± 1.29 to 1.57 ± 0.68 mm. In addition, the Enophthalmos Index decreased from 2.65 to 0.35 mm.

CONCLUSION

This observational study objectively demonstrated that computer-assisted secondary correction for craniofacial fractures can significantly improve facial symmetry. And the authors recommend that virtual surgical planning and intraoperative navigation should be a must step in craniofacial fracture correction.

C-Arm a Useful Tool for Surgeons in Reduction of Zygomatic Complex Fracture: A Comparative Study: Article Type-Original Research

Introduction

Reduction of zygomaticomaxillary (ZMC) fracture is often difficult to evaluate intraoperatively because of it peculiar anatomy and limited accessibility. The purpose of this study is to evaluate the efficacy of use of C-arm as a tool for intraoperative monitoring of ZMC fracture reduction.

Materials and Methods

Group I (C-Arm) and Group II (control group) comprised of patients with isolated unilateral displaced Zygomatic complex (ZMC) fractures and having orbital volume change. The efficacy of use of C-arm intra-operatively was evaluated to analyse the reduction of fracture.

Results

It was observed that mean change in ocular volume was around 1.07cm2 for Group I and 1.51cm2 in Group II. Thus post-operative eye volume was near to normal in Group I than Group II. The change in ocular volume post-operatively was observed to be statistically significant (p-value < 0.05) in both the groups. Post HOC Tukey statistical analysis determined the intergroup relation in change in eye volume between normal, pre- and post-operative and was found to be statistically significant (p-value < 0.05). The intergroup comparison between Group I and Group II was done using ANOVA statistical analysis and was found to be statistically significant (p-value < 0.05).

Discussion

Our study revealed that C-arm is definitively an effective tool in the oral and maxillofacial surgery armamentarium, giving better results with minimal surgical exposure and by eliminating operator related error.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12070-022-03221-y.

The role of intraoperative navigation in surgical treatment of unilateral zygomatic complex fractures: A systematic review and meta-analysis

PURPOSE

The application of a computer-aided navigation system (CANS) in zygomatic complex (ZMC) fractures has been extensively reported, but individual results are heterogeneous. The purpose of this systematic review was to evaluate the role of CANS in the surgical treatment of unilateral ZMC fractures.

METHODS

Electronic retrieval of MEDLINE, Embase, and Cochrane Library (CENTRAL) and manual searching until November 1, 2022 were used to identify cohort studies and randomized controlled trials employing CANS in the surgical treatment of ZMC fractures. The identified reports contained at least 1 of the following outcome variables: accuracy of reduction, total treatment time, amount of bleeding, postoperative complications, satisfaction, and cost. Weighted or mean differences (MD), risk ratios, and corresponding 95% confidence intervals (CI) were calculated, where P＜.05 and I²＞50% random-effect model was adopted, and a vice versa fixed-effect model was adopted. Descriptive analysis was applied to qualitative statistics. The protocol was conducted in accordance with PRISMA guidelines and prospectively registered with PROSPERO (CRD42022373135).

RESULTS

A total of 562 studies were identified, of which 2 cohort studies and 3 randomized controlled trials with 189 participants were included. Meta-analysis indicated that employing CANS significantly decreased the reduction error (MD = -0.86, 95% CI -1.58 to -0.14; P = .02, random-effect model) compared with conventional surgery without using CANS. The differences in total treatment time (preoperative planning time: MD = 1.44, 95% CI -3.55 to 6.43; P = .57 and operative time: MD = 3.02, 95% CI -9.21 to 15.26; P = .63, fixed-effect model) and amount of bleeding (MD = 14.86, 95% CI -8.86 to 38.58; P = .22, fixed-effect model) were not statistically significant between the two groups. Descriptive analysis suggested that postoperative complications, postoperative satisfaction, and cost were also similar with or without CANS.

CONCLUSION

Within the limitations of the present review, the reduction accuracy of unilateral ZMC fractures using CANS is superior to that of conventional surgery. CANS presents limited influence on operation time, amount of bleeding, postoperative complications, postoperative satisfaction, and cost.

Accuracy of virtual planning and intraoperative navigation in zygomaticomaxillary complex fractures: A systematic review

OBJECTIVE

This systematic review aims to investigate the effect of virtual planning on the treatment of zygomaticomaxillary complex (ZMC) traumatology followed by intraoperative navigation. Furthermore, clinical outcomes following intraoperative navigation surgery or conventional surgery will be compared.

MATERIALS AND METHODS

A systematic literature search was conducted in PubMed, Embase, Web-of-Science, and Cochrane on January 1st, 2022. Inclusion criteria were articles using preoperative three-dimensional (3D) virtual planning combined with intraoperative navigation or comparing these 3D methods with conventional methods. Furthermore, at least one of the following outcomes needed to be included in the article: technical accuracy of the procedure, preoperative planning time, operative time, number of fixation points, patient satisfaction, complications, or total costs of the intervention.

RESULTS

Following the screening of 4478 articles, 17 were included. Five articles appeared to indicate a significantly better technical linear accuracy, one article reported better accuracy for rotation and two articles showed better accuracy in restoring orbital volume when using navigation. Nine articles investigated operative time with varying results. Seven articles calculated the additional costs, of which three concluded no extra cost while the others indicated high additional costs or questionable cost-effectiveness.

CONCLUSION

Virtual planning and intraoperative navigation technologies have the potential to assist maxillofacial trauma surgeons in reducing ZMC fractures significantly more accurately and restoring the facial contour in a less invasive manner at an acceptable cost.

REGISTRATION

The protocol for this systematic review (CRD42020216717) was registered in the International Prospective Register of Systematic Reviews (PROSPERO).

Bioresorbable Implants in Reduction of Paediatric Zygomaticomaxillary Complex Fractures Concurrent With Internal Orbital Reconstruction

PURPOSE

To evaluate the clinical effectiveness and safety of bioresorbable implants for treating paediatric zygomaticomaxillary complex (ZMC) fractures with concomitant orbital floor defects.

METHODS

A retrospective review of paediatric patients who underwent ZMC repair with concomitant orbital floor fractures with bioresorbable implants in Shanghai Ninth People's Hospital from July 2015 to June 2019 was performed. The primary outcome measures included ocular motility, diplopia, enophthalmos, facial deformities, and restricted mouth opening, as well as complication rates. Pre- and post-operative computed tomography scans were obtained for clinical diagnosis and surgical effectiveness.

RESULTS

Twenty two children were included in this study. Facial deformities were corrected in all 22 cases by surgical reconstruction postoperatively, and the average relative distance of Portals point-Zygomaxillare and Anteriornasalspine-Zygomaxillare were 1.3 ± 0.6mm ( P = 0.22) and 1.2 ± 0.5mm ( P = 0.19). The eye movement restored to normal in 13 patients. The mean amount of relative enophthalmos was 1.0 ± 0.4 mm ( P = 0.12). 12 cases had complete resolution of diplopia postoperatively at the extremes of the gaze, and 1 case presented persistent diplopia on the down gaze as before, but from level III to level I. Facial numbness was resolved completely in 6 cases, and 2 cases presented with persistent numbness but relieved significantly. The average Hounsfield units of RapidSorb plates and OrbFloor PI were 154 ± 5 and 99 ± 4 respectively on computed tomography image obtained 1 week postoperatively, which showed no obvious difference compared with 0.5 year postoperatively ( P > 0.1). Hounsfield units of implants gradually declined around 1 year postoperatively. Hounsfield units of RapidSorb plates (20 ± 1) were consistent with periorbital tissue during postoperative 2-year follow-up, and Hounsfield units of OrbFloor PI (19 ± 1) were consistent with periorbital tissue during postoperative 1.5-year follow-up. No patients had severe sequelae or implant related complications postoperatively. None of bone nonunion, malunion, infection or rejection occurred during the follow-up periods.

CONCLUSIONS

Open reduction and internal fixation for the treatment of ZMC fracture have achieved significant improvement in functional and cosmetic outcomes postoperatively. Bioresorbable materials have been proved to be effective and safe in the treatment of children's ZMC and orbital wall fractures.

Application of optimized three-dimensional digital surgical guide plates for complex midfacial fractures

INTRODUCTION

The treatment of midfacial fractures is always difficult. The purpose of this study was to verify whether optimized three-dimensional (3D) digital surgical guide plates combined with preformed titanium plates improved the treatment effect in complex midfacial fractures.

PATIENTS AND METHODS

Twenty-six patients with complex midfacial fractures were recruited and randomized into three groups: ten for Group A, eight for Group B, and eight for Group C. Group A was treated with a combination of preformed titanium plates and optimized 3D digital surgical guide plates. Group B was treated with preformed titanium plates only. Group C was treated conventionally. Clinical effects, patient-reported outcome measures (PROMs), midfacial contour, facial symmetry, surgical accuracy, △orbital volume (the absolute value of the bilateral orbital volume difference), and maximum deviation were evaluated in each of the three groups.

RESULTS

Group A had the best postoperative clinical effects and patient-reported outcomes. Significant improvements in midfacial contour (L1[0.72±0.29 mm, P = 0.001], L2[1.04±0.46 mm, P < 0.001]), facial symmetry (S1[0.71±0.30 mm, P < 0.001], S2[0.96±0.58 mm, P < 0.001], S3[0.86±0.40 mm, P < 0.001], S5[0.81±0.16 mm, P = 0.003], S8[0.95±0.30 mm, P < 0.001], S9[1.03±0.38 mm, P < 0.001], S11[0.64±0.46 mm, P < 0.001]) and surgical accuracy (M1[R, 0.82±0.31 mm, P < 0.001], M2[R, 0.87±0.44 mm, P < 0.001], M3[L, 0.88±0.22 mm, P = 0.004], M3[R, 1.06±0.31 mm, P = 0.003], M4[L, 0.96±0.45 mm, P = 0.008], M4[R, 1.11±0.57 mm, P = 0.003], M5[R, 0.76±0.26 mm, P < 0.001], M6[L, 1.00±0.46 mm, P = 0.003], M6[R, 1.00±0.58 mm, P = 0.001], M7[0.87±0.53 mm, P = 0.001], M8[R, 0.91±0.53 mm, P < 0.001], M9[R, 0.81±0.32 mm, P = 0.010], M10[R, 1.19±0.42 mm, P = 0.009], M11[L, 0.85±0.51 mm, P = 0.021], M11[R, 0.96±0.49 mm, P = 0.003]) were found in Group A compared with the other two groups. The results of △orbital volume and maximum deviation analysis showed an ideal surgical treatment effect in Group A.

CONCLUSION

Optimized 3D digital guide plates can accurately locate preformed titanium plates and effectively improve the treatment effect in complex midfacial fractures.

Application of Computer-Aided Design and Individualized Templates for Bilateral Zygomaticomaxillary Complex Fractures

PURPOSE

Reduction of the bilateral zygomaticomaxillary complex (ZMC) fracture with individualized templates based on computer- aided surgical simulation system. To evaluate the practicality and accuracy of this approach in the treatment of bilateral ZMC fracture.

METHODS

Sixteen patients with bilateral ZMC fractures were collected to create a study model. The authors reconstruct the ZMC on one side via the three-dimensional (3D) model, and then mirrored to the opposite side. Multiple individualized templates were made based on the 3D model, and used as intraoperative guidance to reduce fractures. After surgery, the facial symmetry and the position of zygoma were observed. The mouth opening, pupil level, and sensation of infraorbital nerve were evaluated. Some mark points on zygoma were measured and the postoperative horizontal asymmetry rate (H) was calculated. Besides, orbital height and width were measured.

RESULTS

For all patients, the position of bilateral ZMC was basically restored. The patients with restriction of mouth opening all recovered to normal. The H values were less than 3.0% at all mark points. There was almost no difference in bilateral orbital width and height. Meanwhile, there was no significant difference between the preoperative measurements of the ideal virtual 3D model and the postoperative measurements of patients.

CONCLUSIONS

The study proves that application of computer-aided design and individualized templates can accurately guide the reduction operation of ZMC fracture, restore the ideal shape of ZMC, and obtain good facial symmetry.

Preliminary outcomes of the surgical navigation system combined with intraoperative three-dimensional C-arm computed tomography for zygomatico-orbital fracture reconstruction

This study analyzed the outcomes of zygomatico-orbital fracture reconstruction using the real-time navigation system with intraoperative three-dimensional (3D) C-arm computed tomography (CT). Fifteen patients with zygomatico-orbital or isolated orbital/zygoma fractures were enrolled in this prospective cohort. For zygoma reduction, the displacement at five key sutures and the differences between preoperative and intraoperative CT images were compared. For orbital reconstruction, the bilateral orbital volume differences in the anterior, middle, and posterior angles over the medial transitional buttress were measured. Two patients required implant adjustment once after the intraoperative 3D C-arm assessment. On comparing the preoperative and postoperative findings for the zygoma, the average sum of displacement was 19.48 (range, 5.1–34.65) vs. 1.96 (0–3.95) mm (P < 0.001) and the deviation index was 13.56 (10–24.35) vs. 2.44 (0.6–4.85) (P < 0.001). For the orbit, the mean preoperative to postoperative bilateral orbital volume difference was 3.93 (0.35–10.95) vs. 1.05 (0.12–3.61) mm³ (P < 0.001). The mean difference in the bilateral angles at the transition buttress was significantly decreased postoperatively at the middle and posterior one-third. There was no significant difference in orbital volume, angle of the transition zone, and the sum of five zygoma distances between post operative results and preoperative virtual planning. The surgical navigation system with the intraoperative 3D C-arm can effectively improve the accuracy of zygomatico-orbital fracture reconstruction and decrease implant adjustment times.

Three-Dimensional Quantification of Facial Morphology and Movements Using a Wearable Helmet

This work proposes a 3D normative database of facial ranges of motion in adults free from facial disorders. Ten facial movements were analyzed, each targeting the activity of specific muscle groups innervated by the facial nerve. The experimental protocol included a test-retest reliability positioning procedure of 25 skin markers based on clinical expertise in facial morphology. Three maximal voluntary contractions were recorded for each facial movement studied, using a 3D facial motion capture helmet. We included 53 adults free from facial disorders (26 men; age $43\pm 14$ ), evaluated twice one week apart. The reliability of marker positioning was expressed as absolute measurement errors. The range of motion vectors of all markers from the best rest to the maximal voluntary contraction was calculated for each muscle group. Primary, secondary, and tertiary markers were extracted for each facial movement. 3D Procruste and asymmetry indices were developed. This allowed the identification of common thresholds of 10% for the asymmetry index and of 6 mm for the Procruste index, beyond which facial motions would be considered abnormally asymmetric. The normative database quantifies facial motions and allows assessment of the degree of clinical disorders by comparison. This protocol is currently being investigated in patients with chronic unilateral peripheral facial paresis.

Efficacy of surgical navigation in zygomaticomaxillary complex fractures: randomized controlled trial

Accurate reduction is of vital importance in the treatment of zygomaticomaxillary complex (ZMC) fractures. Computer-assisted navigation systems (CANS) have been employed in ZMC fractures to improve the accuracy of surgical reduction. However, randomized controlled trials on this subject are rare and the benefits of CANS remain controversial. The aim of this study was to compare reduction errors between navigation-aided and conventional surgical treatment for ZMC fractures. Thirty-eight patients with unilateral type B ZMC fractures were enrolled. Preoperative computed tomography data were imported into ProPlan software for virtual surgical planning. Open reduction and internal fixation was performed with CANS (experimental group) or without CANS (control group). Postoperative computed tomography scans were obtained to examine the difference between surgical planning and the actual postoperative outcome, namely reduction errors. The median translational reduction errors in the X, Y, and Z axes were 0.80 mm, 0.40 mm, and 0.80 mm, respectively, in the experimental group and 0.53 mm, 0.86 mm, and 0.83 mm, respectively, in the control group (P > 0.05). The median rotational reduction errors in pitch, roll, and yaw were 0.92°, 2.47°, and 1.54°, respectively, in the experimental group and 1.45°, 3.68°, and 0.76°, respectively, in the control group (P > 0.05). In conclusion, compared with conventional reduction surgery, navigation-aided surgery showed no significant improvement in reduction accuracy in the treatment of type B ZMC fractures (Chinese Clinical Trial Registry, registration number ChiCTR1800015559).

Application of real-time surgical navigation for zygomatic fracture reduction and fixation

BACKGROUND

Inappropriate treatment of zygomatic fractures can reduce esthetic and functional outcomes. The aim of this study was to answer the research question: "Among patients with a unilateral zygomatic fracture, is the use of computer-assisted real-time navigation system during fracture reduction precise and accurate to create postoperative facial symmetry?"

METHODS

Using a retrospective cohort study design, we enrolled a cohort of unilateral zygomatic fractures undergoing open reduction and internal fixation (ORIF) with the aid of the computer-based navigation system at Chang Gung Memorial Hospital, Taiwan, during January 2015 and March 2018. The predictor variable was the comparison before and after surgery. The main outcome variables included (1) two-dimensional (2D) reduction of the displacement at five anatomical landmarks: zygomaticofrontal, inferior orbital rim, zygomaticosphenoidal, zygomaticomaxillary, and zygomaticotemporal lines/buttresses and (2) three-dimensional (3D) differences on distances between zygomatic surface to the porion plane and the midpoint of zygomatic arch (ZA) to the mid-porion (MP) plane. The Wilcoxon signed-rank test was computed to compare between pre- and postoperative data, and a p-value less than 0.05 was considered statistically significant.

RESULTS

The cohort comprised 24 subjects (50% females, 75% left-sided) with a mean age of 30.5 +/- 13.8 years. On 2D analysis, the significant fracture reduction was found: 4.78 vs. 1.22 mm, 1.78 vs. 0.40 mm, 3.50 vs. 0.07 mm, 3.06 vs. 0.55 mm, and 2.55 vs. 0.50 mm at zygomaticomaxillary, zygomaticofrontal, inferior orbital rim, zygomaticosphenoidal, and zygomaticotemporal landmarks. The 3D evaluations revealed the significant reduction of the differences between the left and right zygomatic surface to the porion plane (4.09 ± 2.12 vs. 0.46 ± 0.35 mm) and between the left and right ZA midpoints to the MP plane (4.89 ± 2.59 vs. 0.71 ± 0.44 mm) (p<0.001 for both 2D and 3D analyses).

CONCLUSIONS

The results of this study suggest that the real-time surgical navigation system can effectively guide the ORIF of zygomatic fractures. Future research studies should focus on the learning curve and cost-effectiveness analysis of this technique.

Exploring partial intrinsic and extrinsic symmetry in 3D medical imaging

We present a novel methodology to detect imperfect bilateral symmetry in CT of human anatomy. In this paper, the structurally symmetric nature of the pelvic bone is explored and is used to provide interventional image augmentation for treatment of unilateral fractures in patients with traumatic injuries. The mathematical basis of our solution is based on the incorporation of attributes and characteristics that satisfy the properties of intrinsic and extrinsic symmetry and are robust to outliers. In the first step, feature points that satisfy intrinsic symmetry are automatically detected in the Möbius space defined on the CT data. These features are then pruned via a two-stage RANSAC to attain correspondences that satisfy also the extrinsic symmetry. Then, a disparity function based on Tukey's biweight robust estimator is introduced and minimized to identify a symmetry plane parametrization that yields maximum contralateral similarity. Finally, a novel regularization term is introduced to enhance similarity between bone density histograms across the partial symmetry plane, relying on the important biological observation that, even if injured, the dislocated bone segments remain within the body. Our extensive evaluations on various cases of common fracture types demonstrate the validity of the novel concepts and the accuracy of the proposed method.

Fifteen-Year Review of the American Board of Plastic Surgery Maintenance of Certification Tracer Data: Clinical Practice Patterns and Evidence-Based Medicine in Zygomatico-Orbital Fractures

BACKGROUND

From 2005 to 2020, the American Board of Plastic Surgery collected data on 20 common plastic surgery operations as part of the Maintenance of Certification process. These data allow the authors to examine national trends in zygomatico-orbital fracture repair over a 15-year period.

METHODS

Tracer data for zygomatico-orbital fracture repair were reviewed in cohorts from 2005 to 2013 and 2014 to 2020. Results were categorized based on their presence in evidence-based medicine articles published during this period. Differences between years were assessed using the t test or chi-square test as appropriate.

RESULTS

Four hundred thirty patients were included as of March of 2020. Average age was 37 years (range, 6 to 85 years), and 76 percent were male. Operations took place on average 10 days from injury. There were significant decreases in the use of subciliary (31.9 percent versus 10.0 percent; p < 0.001), gingival buccal (84.3 percent versus 56.4 percent; p < 0.001), and lateral brow (45.2 percent versus 22.3 percent; p < 0.001) incisions, with an increase in lower lid external incisions (15.2 percent versus 30.9 percent; p < 0.001); 2.7 percent of patients had a complication requiring readmission and 4.5 percent required reoperation. The incidence of postoperative diplopia was 7.7 percent, and the infection rate was 1.7 percent.

CONCLUSIONS

This article reviews the American Board of Plastic Surgery tracer data for zygomatico-orbital fracture repair. The Maintenance of Certification tracer data provide a national database with longer follow-up and more specific information than comparable databases. Analysis of these data over time enables the authors to describe practice trends and gives surgeons the opportunity to compare their outcomes to national norms.

Is Zygomatic Osteotomy a Viable Option to Achieve Symmetry and Stability in Post-traumatic Residual Deformity of the Zygomaticomaxillary Complex?

PURPOSE

In residual deformity cases, it is difficult to reposition the zygomaticomaxillary-complex (ZMC) intraoperatively, due to resorbed fracture edges, and lack of zygoma analysis to 3-dimensionally quantify the deformity. Instability after zygomatic osteotomy and miniplate fixation (ZOMF) due to the gap between osteotomized segments, scar tissue, muscle pull, and other factors is also unknown. The study aims to evaluate symmetry and stability after ZOMF.

MATERIALS AND METHODS

In this prospective study, a ZMC analysis was designed and patients with unilateral post-traumatic residual deformity (>10 weeks) of ZMC were treated with ZOMF. Measurements were evaluated on affected and unaffected sides at preoperatively, immediately, and 6 months postoperatively using MIMICS software. The primary outcome variable was the symmetry and stability of ZMC. Secondary parameters were changes in orbital volume, diplopia, ocular motility, mouth opening, and patient satisfaction. P < .05 was considered statistically significant. The continuous variables were compared by paired t-test. The change within the continuous variable with time was assessed by repeated measure ANOVA, followed by multiple comparisons using the Bonferroni test. The changes within the categorical variable were assessed by the McNemar test.

RESULTS

Ten patients were enrolled (mean age = 29.2 ± 9.97 years; male:female = 9:1; right:left = 4:6). The mean duration from trauma to surgery was 34.84 ± 31.35 weeks. There was an improvement in the symmetry in anteroposteriorly (P = .005), mediolaterally (P = .001), and at the arch (P = .011) postoperatively. All parameters remained stable at 6 months postoperatively (difference not significant, P > .05); with the median satisfaction score of 4 of 5. Significant improvement in mouth opening (P = .014) and orbital volume (P = .001) was noted.

CONCLUSIONS

Virtual measurements as per the proposed protocol helped in communication and quantifying ZMC. Four-point fixation with miniplates provided enough stability over the 6-month follow-up period.