Comparison of postoperative skeletal stability of maxillary segments after Le Fort I osteotomy, using patient-specific implant versus mini-plate fixation

Long-term maxillary stability after fixation with two or four plates: a 3-D prospective quasi-experimental evaluation

The purpose was to assess through a prospective, interventional and quasi-experimental study the long-term stability of maxilla fixed with two and four plates in Le Fort I osteotomies using computed tomography. A total of 63 patients (mean age 29,9 ± 9,3) with skeletal Class II-III dentofacial deformity were recruited. Thirty-six patients were fixed with two-plates and 27 patients with four plates. Preoperative, ≤6 months postoperative and ≥12 months postoperative tomography scans were taken. Data were imported to Dolphin Imaging®, superimposed and analyzed 3-dimentionally. Descriptive statistics were reported, quantitative variables were evaluated by the Kolmogorov Smirnov test, for categorical variables chi-square test with Yates' correction was used and Mann-Whitney test for those with asymmetric distribution. Spearman's test was used for correlation between quantitative variables. In the group of 4-plates, significant relapse was found in the vertical landmark A (p = 0.004). In the group of two plates, sagittal and vertical PNS and transversal A skeletal landmarks exhibited the highest relapse medians. Significant correlations between occlusal plane rotations and the vertical A landmark were found in the group of 2-plates (p = 0.043) and for all dental landmarks in the vertical axis in the group of 4-plates. (p = 0.024). Fixation with 2-plates was found to be stable in the long-term. Occlusal plane rotations and vertical maxillary repositioning must be taken under consideration when fixating with 2 or 4-plates respectively.

Patient-Specific Le Fort I Osteotomy Plates Are More Stable than Stock Plates in Patients with Cleft Lip and Palate

BACKGROUND

There is evidence that patient-specific plate fixation for Le Fort I osteotomies (LFI) is more stable than traditional plate fixation. The purpose of this study was to evaluate stability of LFI in patients with cleft lip and palate and determine stability differences between patient-specific and stock plates.

METHODS

Consecutive patients with cleft lip and palate who underwent isolated LFI by one surgeon (B.L.P.) between 2016 and 2021 were included. The predictor variable was type of plate used for fixation (patient-specific or stock). The outcome variable was magnitude of relapse in the vertical (nasion to A point) and horizontal planes (basion to A point) at 1 year after LFI using 3-dimensional cone beam computed tomography. Statistical analysis included independent samples t , Mann-Whitney U , Fisher exact, and chi-square tests. Values of P < 0.05 were significant.

RESULTS

The sample included 63 subjects; 23 in the patient-specific group (36.5%) and 40 in the stock group (63.5%). Groups were comparable by sex, race, age at surgery, cleft type, presence of pharyngeal flap, and magnitude of horizontal movement ( P > 0.136 for all). Subjects who underwent patient-specific plate fixation were less likely to have greater than or equal to 1-mm change at 1 year in the horizontal (4.3% versus 50.0%; P < 0.001) and vertical planes (4.3% versus 65.0%; P < 0.001) compared with stock plates. For patients who had greater than 10-mm horizontal advancement, the patient-specific plates had significantly less relapse (patient-specific plates, 0.105 ± 0.317 mm; stock plates, 1.888 ± 1.125 mm; P = 0.003).

CONCLUSION

Patient-specific plate fixation of LFI is more stable and demonstrates less relapse after 1 year than stock plates.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

Skeletal stability after mandible bilateral sagittal split osteotomy - comparison of patient-specific implant and mini-plate fixation: A retrospective study

The aim of the study was to compare the stability of the virtual surgical planning (VSP) and computer-aided design accompanied by patient-specific implants (PSIs) and conventional mini-plates in mandible advancement with bilateral sagittal split osteotomy (BSSO). This retrospective study evaluates the clinical and cephalometric records of 53 patients (12 male, 41 female) treated with BSSO in Helsinki University Hospital. Subjects were divided into two groups: VSP-PSI (21 patients: 4 male and 17 female; mean age 38 years, range 25-53 years); and conventional wafer-based repositioning with mini-plate fixation (32 patients: 8 male and 24 female; mean age 39 years, range 21-56 years). The effect of the amount and direction of the advancement on the stability was also analysed individually. The standardized lateral cephalometric radiographs in three time points were analysed to compare the groups. After surgery (T2), there were no differences between groups in cephalometric variables. During follow-up (T2-T3), the cephalometric variables in both Groups A and B were stable, so there was no difference in stability between the VSP-PSI and the conventional mini-plate groups. During follow-up, the mandibles rotated clockwise or counterclockwise, relapsed towards their original direction, and the changes were statistically significant (jaw relationship; p = 0.018, soft tissue profile; p = 0.025); when the advancement of mandible was >6 mm, the increase in gonial angle compared to mandibles advanced ≤6 mm was statistically significant (p = 0.03). VSP-PSI and conventional mini-plate fixation can be considered equally stable. Large advancements with counterclockwise rotation regardless of fixation method are more susceptible to relapse. VSP-PSI alone cannot solve the relapse-related concerns in mandible osteotomy.

Accuracy and influencing factors of maxillary and mandibular repositioning using pre-bent locking plates: a prospective study

In-house repositioning methods based on three-dimensional (3D)-printing technology and the use of pre-bent plates has been gaining popularity in orthognathic surgery. However, there remains room for further improvement in methods and investigations on clinical factors that affect accuracy. This single-centre, prospective study included 34 patients and aimed to evaluate the accuracy and factors influencing maxillary and mandibular repositioning using pre-bent locking plates. The plates were manually pre-bent on the 3D-printed models of the planned position, and their hole positions were scanned and reproduced intraoperatively with osteotomy guides. The accuracy of repositioning and plate-hole positioning was calculated in three axes with the set landmarks. The following clinical factors that affect repositioning accuracy were also verified: deviation of the plate-hole positioning, amount of planned movement, and amount of simulated bony interference. The median deviations of the repositioning and hole positioning between the preoperative plan and postoperative results were 0.26 mm and 0.23 mm, respectively, in the maxilla, and 0.69 mm and 0.36 mm, respectively, in the mandible, suggesting that the method was highly accurate, and the repositioning concept based on the plate hole and form matching was more effective in the maxilla. Results of the correlation test suggest that large amounts of bony interference and plate-hole positioning errors in the up/down direction could reduce mandibular repositioning accuracy.

Unilateral Cleft Lip and Palate Has Asymmetry of Bony Orbits: A Retrospective Study

Facial asymmetry is common in unilateral clefts. Since virtual surgical planning (VSP) is becoming more common and automated segmentation is utilized more often, the position and asymmetry of the orbits can affect the design outcome. The aim of this study is to evaluate whether non-syndromic unilateral cleft lip and palate (UCLP) patients requiring orthognathic surgery have asymmetry of the bony orbits. Retrospectively, we analyzed the preoperative cone-beam computed tomography (CBCT) or computed tomography (CT) data of UCLP (n = 15) patients scheduled for a Le Fort 1 (n = 10) or bimaxillary osteotomy (n = 5) with VSP at the Cleft Palate and Craniofacial Center, Helsinki University Hospital. The width, height, and depth of the bony orbit and the distance between the sella turcica and infraorbital canal were measured. A volumetric analysis of the orbits was also performed. The measurements were tested for distribution, and the cleft side and the contralateral side were compared statistically with a two-sided paired t-test. To assess asymmetry in the non-cleft population, we performed the same measurements of skeletal class III patients undergoing orthognathic surgery at Päijät-Häme Central Hospital (n = 16). The volume of bony orbit was statistically significantly smaller (p = 0.014), the distance from the infraorbital canal to sella turcica was shorter (p = 0.019), and the anatomical location of the orbit was more medio-posterior on the cleft side than on the contralateral side. The non-cleft group showed no statistically significant asymmetry in any measurements. According to these preliminary results, UCLP patients undergoing orthognathic surgery show asymmetry of the bony orbit not seen in skeletal class III patients without a cleft. This should be considered in VSP for the correction of maxillary hypoplasia and facial asymmetry in patients with UCLP.

Use of Submental Intubation in the Full-Face Makeover (Orthognathic Surgery, Facial Prosthesis Combined With Rhinoplasty)

BACKGROUND

Submental intubation is an intubation technique used for the management of airways in patients who suffered from complex maxillofacial trauma. Few studies focused on the role of submental intubation during Full-Face Makeover, like orthognathic surgery, facial prothesis, and rhinoplasty.

METHODS

Authors describe a case series of 5 patients who underwent to Full-Face Makeover with submental intubation to manage the airways. The authors started with the Le Fort I subspinal osteotomy. The maxillary repositioning was guided through a 3D printed intermediate splint in all cases (previously simulated with Dolphin software).Subsequentially, the bilateral sagittal split osteotomy was performed. The mandibular repositioning was guided through a 3D printed final splint. The genioplasty was performed with a horizontal osteotomy after a labial mucosa incision. After the genioplasty, the authors used the incision previously used for the Le Fort I osteotomy to bluntly dissect the tissues in order to insert a custom-made polyether ether ketone zygomatic prosthesis. Lastly, an open rhinoplasty was performed.

RESULTS

All the surgery lasted a mean less 6 hours. The submental intubation was removed in the operating room, at the end of the surgery. The patients were then discharged from the hospital 2 days after the surgery in all cases.

CONCLUSIONS

Submental intubation is a valid method for the airway management in maxillofacial trauma and can be extended in case of Full-Face Makeover like orthognathic surgery combined with rhinoplasty. The absence of nasal traumatism during surgery leads to a more accurate rhinoplasty, with a greater satisfaction for the patient.

Early experience of wafer-free Le Fort I osteotomy with patient-specific implants in cleft lip and palate patients

PURPOSE

The use of virtual surgical planning and patient-specific saw and drill guides combined with customized osteosynthesis is becoming a gold standard in orthognathic surgery. The aim of this study is to report preliminary results of the use of virtual surgical planning and the wafer-free PSI technique in cleft patients.

MATERIALS AND METHODS

Patient-specific saw and drill guides combined with milled patient-specific 3D titanium alloy implants were used in reposition and fixation in Le Fort I osteotomy of 12 cleft patients. Surgical information was retrieved from hospital records. Pre- and post-operative lateral cephalograms were analyzed.

RESULTS

In 10 of 12 cases, the implants fitted as planned to predesigned drill holes and bone contours with high precision. In one patient, the mobilization of the maxilla was too demanding for virtually planned advancement, and the implants could not be used. In another patient, PSI fitting was impaired due to an insufficient mobilization of maxilla and tension on PSI fixation with screws. After the surgery, the mean advancement of the anterior maxilla (point A) of all patients was 5.8 mm horizontally (range 2.7-10.1) and -3.1 mm vertically (range -9.2 to 3.4). Skeletal relationships of the maxilla and mandible could be corrected successfully in all patients except for the one whose PSI could not be used.

CONCLUSIONS

Virtual surgical planning combined with PSI is a possible useful clinical adjunct for the correction of maxillary hypoplasia in cleft patients. Large maxillary advancements and scarring may be cause problems for desired advancement and for the use of implants.

Biomechanical evaluation of Chinese customized three-dimensional printed titanium miniplate in the Lefort I osteotomy: A finite element analysis

Objectives

This work aims to evaluate the biomechanical behavior of Chinese customized three-dimensional (3D) -printed miniplates by means of finite element analysis (FEA).

Methods

A 3D Lefort I osteotomy model was established by Mimics. Two models were established to compare the strain behaviors of customized miniplate and conventional L-shaped miniplate. Hypermesh and ABAQUS were used to establish computer-aided engineering finite element models. The stress distribution on the mini-plates, screws and bone and the relative displacement of the maxilla segments were analyzed by loading postoperative occlusal force.

Results

The displacements for customized mini-plate fixation were notably smaller than L-shaped mini-plate fixation. The maximum stresses on the screws, mini-plates and cortical bone for customized mini-plates were smaller than that for L-shaped miniplates.

Conclusion

Chinese customized 3D-printed miniplates provide better postoperative stability and offer a good alternative to the conventional L-shaped miniplate system.

Simultaneous PSI-Based Orthognathic and PEEK Bone Augmentation Surgery Leads to Improved Symmetric Facial Appearance in Craniofacial Malformations

(1) The aim of the present study was to compare the outcome of facial symmetry after simultaneous digitally planned patient-specific implant (PSI-) based orthognathic surgery and polyether ether ketone (PEEK) bone augmentation in patients with craniofacial malformations. (2) To evaluate the outcome of the two different surgical approaches (conventional PSI-based orthognathic surgery versus simultaneous PSI-based orthognathic surgery with PEEK bone augmentation), a comparison of five different groups with a combination of the parameters (A) with vs. without laterognathia, (B) syndromic vs. non-syndromic, and (C) surgery with vs. without PEEK bone augmentation was conducted. The digital workflow comprised cone beam CT (CBCT) scans and virtual surgery planning for all patients in order to produce patient specific cutting guides and osteosynthesis plates. Additionally, deformed skulls were superimposed by a non-deformed skull and/or the healthy side was mirrored to produce PSI PEEK implants for augmentation. Retrospective analyses included posterior-anterior conventional radiographs as well as en face photographs taken before and nine months after surgery. (3) Simultaneous orthognathic surgery with PEEK bone augmentation significantly improves facial symmetry compared to conventional orthognathic surgery (6.5%P (3.2-9.8%P) (p = 0.001). (4) PSI-based orthognathic surgery led to improved horizontal bone alignment in all patients. Simultaneous PEEK bone augmentation enhanced facial symmetry even in patients with syndrome-related underdevelopment of both soft and hard tissues.

Postoperative skeletal stability at the one-year follow-up after splintless Le Fort I osteotomy using patient-specific osteosynthesis versus conventional osteosynthesis: a randomized controlled trial

The purpose of this study was to assess the 1-year skeletal stability of the osteotomized maxilla after Le Fort I surgery, comparing conventional osteosynthesis with patient-specific osteosynthesis. Patients were assigned to a conventional or patient-specific osteosynthesis group using prospective randomization. The primary outcome was the three-dimensional change in postoperative skeletal position of the maxilla between the 2-week and 1-year follow-up cone beam computed tomography scans. Fifty-eight patients completed the protocol for the 2-week postoperative analysis, and 27 patients completed the 1-year follow-up study protocol. Of the 27 patients completing the entire protocol, 13 were in the conventional group and 14 in the patient-specific osteosynthesis group. The three-dimensional translation analysis showed that the use of the patient-specific osteosynthesis resulted in a skeletally stable result, comparable to that of conventional miniplate fixation. For both the patient-specific osteosynthesis and conventional miniplate fixation groups, median translations of less than 1 mm and median rotations of less than 1° were observed, indicating that both methods of fixation resulted in a stable result for the 27 patients examined. For the Le Fort I osteotomy, the choice between patient-specific osteosynthesis and conventional osteosynthesis did not affect the postoperative skeletal stability after 1 year of follow-up.

Custom made cutting guides and osteosynthesis plates versus CAD/CAM occlusal splints in positioning and fixation of the maxilla in orthognathic surgery: A prospective randomized study

The aim of this study is to compare the accuracy of maxilla positioning in orthognathic surgery with the use of custom-made devices (cutting guides and patient-fitted osteosynthesis plates) comparing to CAD/CAM splints. A prospective randomized study was performed. Patients with dentofacial deformities undergoing orthognathic surgery were compared, using customized guides (experimental group) vs. CAD/CAM surgical splints (control group) for the repositioning of the upper maxilla. Preoperative and postoperative CT scans were used to compare positioning and fixation of the maxilla in the three planes of space. A total of 30 patients were included in the study (15 patients in each study group). The mean error obtained with customized guides was 0.8 mm (range 0.1-1.9) in the anterior-posterior axis, 0.4 mm (range 0-1.4) in the vertical axis and 0.2 mm (range 0-1.1) in the horizontal axis. There were statistically significant differences in the anterior-posterior and vertical axes in favour of the customized implants, whereas there were no differences in the horizontal plane. Furthermore, there was a mean reduction of the operative time of 36.5 min in the experimental group. Within the limitations of the study it seems that patient specific surgical guides should be preferred when accuracy of repositioning of the maxilla and saving operative time are the priority.

Postoperative stability of two common ramus osteotomy procedures for the correction of mandibular prognathism: A randomized controlled trial

The aim of this randomized controlled trial was to compare the skeletal stability between sagittal split ramus osteotomy (SSRO) and intraoral vertical ramus osteotomy (IVRO) in the treatment of mandibular prognathism. Patients presenting with mandibular prognathism and scheduled for orthognathic surgery were randomized into either the SSRO group or the IVRO group. Changes at B-point were assessed by serial tracing of lateral cephalograms, which were taken preoperatively, and at 2 weeks, 6 months, 1 year, and 2 years postoperatively. Ninety-eight patients were recruited, with 49 patients in each group. Between 2 weeks and 6 months postoperatively, there was significantly more surgical relapse in the horizontal direction (anterior movement) in the SSRO group when compared with the IVRO group (1.83 mm (SD 2.91 mm) vs 0.49 mm (SD 2.32 mm); p = 0.019). At 2 years, there was more surgical relapse in the horizontal direction in the SSRO group than in the IVRO group (0.27 mm (SD 0.34 mm) vs 0.10 mm (SD 0.29 mm); p = 0.014). There were also more absolute changes (irrespective of direction) at B-point in the SSRO group than in the IVRO group at postoperative 6 months, 1 year, and 2 years (p = 0.016, 0.049, and 0.045, respectively). The amounts of change at B-point as percentages of total mandibular setback were 1.3% and 3.5% in the IVRO group and SSRO group, respectively. There were no differences in vertical changes between the two groups at any time points. In conclusion, the horizontal stability at B-point was shown to be superior in the IVRO group compared with the SSRO group in the correction of mandibular prognathism during the 2-year follow-up. Although the exact clinical importance of this difference is unknown at this time, this possible benefit may be an important key factor when deciding which osteotomy technique to employ for mandibular setback.

Patient Specific Implants to Solve Structural Facial Asymmetry After Orthognathic Surgery

ABSTRACT

Facial asymmetry is a challenge for surgeons. Some surgical strategies could be used involved soft or hard tissue of the face. The aim of this report is to show the use of patient specific implants (PSI) in a puzzle strategy based on computer aided design/computer aided manufacturer to solve a complex structural facial asymmetry after orthognathic surgery. Twenty-five-year-old male patient complain for facial asymmetry after orthognathic surgery; main deformity was related to the shape of mandibular bone in the ramus, angle, and body. After mirror image, was chose an augmentation in the right side using 2-pieces patient specific implants and the bone reduction in the vertical high of the mandibular body in the left side. Surgical technique was realized by intra oral approach installing the ramus segment at first approach and the body segment as second to obtain stability in the fitting implant-bone-implant; the left side was treated using a guide for osteotomy; after 1-year follow-up no infection or complication was observed and facial symmetry was obtained. It is possible to conclude that the puzzle technique using polyetheretherketone can be applied to obtain predictable results in a simple strategy to solve a complex problem.

Peri- and postoperative complications in Le Fort I osteotomies

This retrospective study was performed to report the peri- and postoperative complications encountered by patients who underwent Le Fort I osteotomy, as well as predictor variables affecting the risk of complications. Patients who underwent only Le Fort I osteotomy were included in the study. Information on peri- and postoperative complications were collected from the patient data records. The effects of certain predictor variables on complication rates were also studied. Twenty-four per cent of the patients suffered from complications, six (6.1%) of whom were reoperated. Most of the complications were minor and transient. Compared with one-piece osteotomy, segmental osteotomy was a significant risk factor predisposing patients to postoperative complications (p = 0.04619). Additionally, the use of patient-specific implants seemed to increase the risk of both perioperative and postoperative complications (p = 0.0248). Currently, the conventional plate fixation method is the primary method in Le Fort I osteotomies. Careful patient selection, surgical planning, and selection of surgical technique seem to be the most important factors in reducing the complication risk. Special attention should be paid with segmental osteotomy surgery.

Variables associated with stability after Le Fort I osteotomy for skeletal class III malocclusion

The purpose of this study was to assess skeletal stability and predictors of relapse in patients undergoing an isolated Le Fort I osteotomy. A retrospective cohort study of 92 subjects undergoing Le Fort I osteotomy for Class III malocclusion was implemented. Predictor variables were demographic and perioperative factors. The primary outcome variable was postoperative skeletal position with relapse defined as >2mm sagittal and/or vertical change at A-point on serial lateral cephalograms at immediate postoperative, 1 year, and latest follow-up time points. Mean advancement at A-point was 6.28±2.63mm and mean lengthening was 0.92±1.76mm. Eight subjects (8.70%) had relapse (>2mm) in the sagittal plane, and two subjects (2.17%) in the vertical plane. No subjects required reoperation for relapse as overbite and overjet remained in an acceptable range due to dental compensation. In regression analysis, magnitude of maxillary advancement was an independent predictor of relapse in the sagittal plane (P=0.008). There were no significant predictors of relapse in the vertical plane. This study suggests that isolated Le Fort I osteotomy for correction of skeletal Class III malocclusion is a stable procedure and that greater advancement is an independent risk factor for sagittal relapse.

Third-generation slotplates for orthognathic and facial corrective surgery

The aim of this study was to retrospectively assess the osteosynthesis material-related morbidity rates of third-generation (3.0) slotplates, and to compare those with the previously researched second-generation (2.0) slotplates. In the 2.0 slotplate design, there were additional tabs in line with the vertical slotted screw hole; in between these tabs, the additional locking screw was placed. In the 3.0 slotplates, these tabs were replaced by a full screw hole for the locking screw, and the 3.0 slotplates are slightly broader than the 2.0 slotplates. Osteosynthesis material-related morbidity rates after Le Fort I-type, zygoma-valgisation, and chin osteotomies were assessed in a cohort receiving 3.0 slotplates in a tertiary care centre and compared to a previously analysed cohort receiving 2.0 slotplates in the same tertiary care centre. Medical records of 77 patients (101 surgeries) receiving 3.0 slotplates were reviewed. Plate infection and plate removal rates were low in the 3.0 slotplate group (2.6% (p = 0.123) and 3.9% (p = 0.103), respectively). No delayed union or non-union occurred in the 3.0 slotplate group. Comparing the morbidity rates with the 2.0 slotplate cohort did not yield any significant differences. Although there was a tendency towards better outcomes with 3.0 slotplates compared to the 2.0 slotplates, the outcome differences did not reach statistical significance.

Accuracy of mandible-independent maxillary repositioning using pre-bent locking plates: a pilot study

The double splint method is considered the gold standard for maxillary repositioning, but the procedure is lengthy and prone to error. Recent splintless methods have shown high repositioning accuracy; however, high costs and technical demands make them inaccessible to many patients. Therefore, a new cost-effective method of mandible-independent maxillary repositioning using pre-bent locking plates is proposed. Plates are bent on maxillary models in the planned position prior to surgery. The locations of the plate holes are replicated during surgery using osteotomy guides made from thermoplastic resin sheets. Pre-bent plates are subsequently fitted onto the maxilla, and plate holes are properly set to reposition the maxilla. The purpose of this study was to evaluate the accuracy of this method for maxillary repositioning and the reproducibility of the plate holes. Fifteen orthognathic surgery patients were evaluated retrospectively by superimposing preoperative simulations over their postoperative computed tomography models. The median deviations in maxillary repositioning and plate hole positioning between the preoperative plan and postoperative results were 0.43mm (range 0-1.55mm) and 0.33mm (range 0-1.86mm), respectively. There was no significant correlation between these deviations, suggesting that the method presented here allows highly accurate and reliable mandible-independent maxillary repositioning.