Pre-bent Plates Research Articles

Use of reconstruction plates prebent on three-dimensional models to reduce the complications of mandibular reconstruction

Background/purposeThough the gold standard method for mandible reconstruction of the defect from segmental mandibulectomy is by osseous flap or graft, using reconstruction plates is still indicated in some cases. Traditionally, the plate is bended immediately after the segmental mandibulectomy by freehand. However, it's difficult to fit well to the original position of mandible, which may result in more complications. This study therefore aimed to investigate whether using prebent plates on computer-aided 3D printing models could reduce the complication rate. Materials and methodsPatients who received mandible reconstruction by reconstruction plate from 2018 to 2022 were enrolled and evaluated in this study. The data, including demographics, indications for surgery, pre-existed preoperative and postoperative therapies, classification of defects, and postoperative outcomes were collected and analyzed. ResultsA total of 52 patients were enrolled in our study. The prebent group exhibited a significantly lower complication rate than that of the immediately bent group (P = 0.012). Other risk factors of plate complications included postoperative adjuvant radiotherapy (P = 0.017) and previous surgery (P = 0.047). The complication-free survival rate was also better in the prebent group in a 3-year follow-up period (P = 0.012). ConclusionPrebent plates on computer-aided printing models proved to be an effective approach to reduce the complications for mandibular reconstruction in segmental mandibulectomy.

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.

Proximal segment positioning using pre-bent plates locating surgical guides versus conventional maneuver in mandibular setback surgery. A randomized clinical trial.

Proximal segment positioning using pre-bent plates locating surgical guides versus conventional maneuver in mandibular setback surgery. A randomized clinical trial.

A Novel Orthognathic Surgery With a Half-Millimeter Accuracy for the Maxillary Positioning Using Prebent Plates and Computer-Aided Design and Manufacturing Osteotomy Guide.

This retrospective study aimed to assess the accuracy of prebent plates and computer-aided design and manufacturing osteotomy guide for orthognathic surgery. The prebent plates correspondent to the planning model were scanned with a 3-dimensional printed model for guide design and used for fixation. Forty-two patients who underwent bimaxillary orthognathic surgery using computer-aided design and manufacturing intermediate splint with the guide (guided group: 20 patients) or with conventional fixation under straight locking miniplates (SLMs) technique (SLM group: 20 patients) were analyzed. A deviation of the maxilla between the planned and postoperative positions was evaluated using computed tomography, which was taken 2 weeks before and 4 days after the surgery. The surgery time and the infraorbital nerve paranesthesia were also evaluated. The mean deviations in the mediolateral ( x ), anteroposterior ( y ), and vertical directions ( z ) were 0.25, 0.50, and 0.37mm, respectively, in the guided group, while that in the SLM group were 0.57, 0.52, and 0.82mm, respectively. There were significant differences in x and z coordinates ( P <0.001). No significant difference in the surgery duration and paranesthesia was seen, suggesting the present method offers a half-millimeter accuracy for the maxillary repositioning without increasing the risk of extending surgery duration and nerve complication.

The value of prebent reconstruction plates and in-house 3D printing

IntroductionReconstruction plates, prebent on 3D printed models, are a cheap, quick, and safe solution to improve mandibular reconstruction procedures. The European Medical Device Regulation has changed recently and severely affects 3D printing in hospitals. Therefore, its legitimation must be discussed. This retrospective observational Case-Control Study aimed to evaluate the impact of prebent reconstruction plates on the condylar position in the temporomandibular joint after continuity resection of the mandible in oncological cases. Materials and MethodsWe included patients who underwent segmental mandibular resection without exarticulation of the condyle or history of prior surgery. The patients were divided into groups with prebent plates on a stereolithographic model and intraoperatively bent reconstruction plates. The segmental defects were categorized using the Jewer Classification. Computed Tomography (CT) scans before and after surgery were analyzed using a standardized method to measure the metric movement of the condyles, as well as their angulation to reference planes to quantify positional changes (primary outcome measures). The influence of the defect location, according to the Jewer classification, was evaluated as a secondary outcome measure. Results73 patients, including 33 with preformed reconstruction plates, were included. We could show significantly fewer rotational deviations in cases of prefabricated osteosynthesis in the coronal plane (p<0,001) and in the sagittal plane (p<0,027). DiscussionUsing preformed reconstruction plates on 3D printed models improves the correct anatomical position of the condyle after mandibular resection. Especially Jewer-class-L defects seem to benefit from individualized reconstruction plates.

170. The Nottingham Waferless Orthognathic Surgical Experience using In-House Reconstructive Scientists

Surgical planning of orthognathic cases has always followed the traditional planning route of models, lateral cephalogram, use of wafers and intra-operative fixation to predefined surgical wafers. In our unit we have modified this technique over the last five years and created a technique which is essentially waferless surgery with the aid of our reconstructive scientists who are based on site and provide us with surgical stents and pre-bent plates.

Computer-guided buccal cortical plate separation for removal of calcified benign odontogenic tumors affecting the mandibular angle region

PurposeSurgical removal of intra-bony calcific benign lesions is technically challenging regarding its accessibility, proximity to vital structures, and deteriorating effect on the remaining bony structures.MethodsComputer-guided buccal cortical plate separation was performed for ten patients using patient-specific osteotomy locating guides and pre-bent plates. The guide was designed to outline the osteotomy, the buccal cortical plate was separated, the lesion was removed, and finally, the pre-bent plates were used to fix the separated cortex.ResultsSurgical procedures were uneventful for all patients, operation time was 39.5 ± 13.01 min, postoperative pain decreased within the follow-up time intervals, and there was a statistical significant difference between the time intervals (P value < 0.001). Edema and trismus were acceptable. One case showed nerve affection which resolved after 4 weeks.ConclusionComputer-guided buccal cortical plate separation for removal of intra-bony calcified benign lesions provides a promising approach, especially for inexperienced surgeons.Trial registrationClinicalTrials.gov NCT05329974. Registered on 6 April 2022—retrospectively registered.

Secondary Mandible Reconstruction with Computer-Assisted-Surgical Simulation and Patient-Specific Pre-Bent Plates: The Algorithm of Virtual Planning and Limitations Revisited

Despite the known advantages of virtual surgical planning and three-dimensional (3D) printing, translation of virtual planning to actual operation is a challenge, especially in secondary mandibular reconstruction. Patients who underwent secondary microvascular mandibular reconstruction were retrospectively reviewed and categorized into three categories as follows: (i) defect not crossing the midline (category I); (ii) defects crossing the midline with availability of previous imaging data (category II) and; (iii) defects crossing the midline with unavailability of previous imaging data (category III). The resulting 3D printed models were used as an effective guide for plate bending during secondary reconstruction surgery. Accuracy of the reconstruction was evaluated by superimposing post-operative images over virtual plan. Out of eleven patients, five were category I, three were category II, and three were category III. The mean linear discrepancy between the planned and post-operative position was measured. A Mann-Whitney U test was conducted to compare mean discrepancy among the groups showed no significant difference between group I and group II (p &gt; 0.05) whereas comparison of groups I and II with group III showed a significant difference (p &lt; 0.01). The proposed algorithm for the generation of defect template for manual plate bending during secondary reconstruction of mandibular defects is valid with acceptable accuracy in various defect configurations.

Short-Segment Drilling Guides for the Management Comminuted Mandibular Fractures.

Treatment of a severely comminuted mandibular fracture is challenging. This technical note describes a novel office-based workflow, combining virtual surgery planning with short-segment drilling guides. The authors reduced the comminuted mandibular fractures via virtual surgery planning. Then, the reconstructed mandible model was printed using an in-house 3D printer. Next, the reconstruction plate was preformed according to the shape of the mandibular model surface, and the position of the screw hole in the mandibular surface was determined. Finally, hand-made short-segment drilling guides for screw position transfer were fabricated with temporary resin. During the operation, the authors reset the guides for the drill to make screw holes as planned. After the hole was drilled, the pre-bent plate was applied to the mandible. The fracture was expected to be reduced, when tightening the screws. in our workflow, by using short and simple operative procedures, the authors were able to achieve precise reduction and reduce the operation time.

Digital planning and individual implants for secondary reconstruction of midfacial deformities: A pilot study

ObjectiveTo evaluate the feasibility and accuracy of implementing three‐dimensional virtual surgical planning (VSP) and subsequent transfer by additive manufactured tools in the secondary reconstruction of residual post‐traumatic deformities in the midface.MethodsPatients after secondary reconstruction of post‐traumatic midfacial deformities were included in this case series. The metrical deviation between the virtually planned and postoperative position of patient‐specific implants (PSI) and bone segments was measured at corresponding reference points. Further information collected included demographic data, post‐traumatic symptoms, and type of transfer tools.ResultsEight consecutive patients were enrolled in the study. In five patients, VSP with subsequent manufacturing of combined predrilling/osteotomy guides and PSI was performed. In three patients, osteotomy guides, repositioning guides, and individually prebent plates were used following VSP. The median distances between the virtually planned and the postoperative position of the PSI were 2.01 mm (n = 18) compared to a median distance concerning the bone segments of 3.05 mm (n = 12). In patients where PSI were used, the median displacement of the bone segments was lower (n = 7, median 2.77 mm) than in the group with prebent plates (n = 5, 3.28 mm).ConclusionThis study demonstrated the feasibility of VSP and transfer by additive manufactured tools for the secondary reconstruction of complex residual post‐traumatic deformities in the midface. However, the median deviations observed in this case series were unexpectedly high. The use of navigational systems may further improve the level of accuracy.

“Custom” Plate in a Day—Accurate Predictive Hole Fabrication Using Point-of-Care 3-Dimensional Printing

In computer surgical planned (CSP) fibular reconstructions of the mandible, custom plates facilitate accurate and efficient transfer of the digital plan intraoperatively by a way of predrilled fixation holes. Stock plates are more easily accessible and are more economical but typically preclude the utilization of these predictive holes. The purpose of this article is to describe an accurate and economical alternative to custom plates, while still having the ability to create predictive holes for plate alignment and execution of a digital surgical plan. An invitro accuracy study was performed on a point-of-care resin-printed predictive hole guide termed "prebent plate analog" (PPA). Twenty stock 2.0 reconstruction plates prebent against a 3-dimensional printed mandibular model reconstructed with a 2-piece fibula were used to fabricate 20 PPAs. The proximal and distal 4 holes of each prebent plate and corresponding PPA were assessed using a heat map overlay, measuring difference in millimeters between matching points of the predictive hole segments. The median distance from the points of reference in the PPA versus the prebent plate was calculated for each predictive hole position in addition to the average error of the PPA to the stock plate. Eighteen PPAs were used for statistical analysis; 2 were damaged in transport. The mean error between the body (-0.265) and condylar segments (-0.116mm) and mean difference in error between the proximal predictive holes (-0.124mm) and distal predictive holes (-0.215mm) on the PPA were not statistically different (P=.061, P=.314 general estimating equation regression, respectively). The mean error across the PPA predictive holes and corresponding holes of the prebent plates was -0.194mm (P<.001, general estimating equation regression). The PPA is a precise and accurate analog that faithfully replicates the position of proximal and distal components of a prebent stock plate, thereby allowing for predictive hole placement in lieu of a custom plate in fibula mandibular reconstruction cases.

Accuracy of midface advancement using patient-specific surgical guides and pre-bent plates versus conventional interocclusal wafers and conventional plate fixation in quadrangular Le Forte II osteotomy. A randomised controlled trial

The aim of this study was to assess the accuracy of quadrangular Le Fort II osteotomy and midface advancement utilising digitally fabricated surgical guides with pre-bent plates compared with conventional interocclusal wafers. Twenty patients with midface deficiency were allocated randomly to two groups: patient-specific surgical guides and pre-bent titanium miniplates were utilised in the study group, while conventional interocclusal wafers with intraoperatively adapted titanium miniplates were utilised in the control group. The accuracy of virtual planning was assessed in both groups using computed tomography (CT). Both groups showed accurate transfer of the plan, but the computer-guided group showed significantly greater accuracy and a shorter surgical time than the conventional group. The use of patient-specific surgical guides and pre-bent plates represents a promising computer-guided approach especially for inexperienced surgeons. Nevertheless, a major limitation is increased overall cost compared with the conventional approach.

The Judgement for Development of Virtual Surgical Planning and Three-Dimensional Bio-Printing for Superior Reconstruction of Mandibular Defect by Fibular Graft on Head-Neck Cancer

Oncological resection followed by reconstruction with a free fibular graft is still considered to be the gold standard treatment for functional and prosthetic rehabilitation of oral cancer patients. But this tedious traditional process is challenging for surgeons, as they have to deal with associated curve anatomy, surrounding innervations, and maintenance of functional and aesthetical acceptability. Such manual and operator’s skill dependent surgery can commonly demand a longer treatment duration; leading to an increased risk for prolonging the period of ischemia with increased morbidity, which frequently ends with an uncertain, unsatisfactory outcome. Technological advancements in the 20th and 21st centuries present a revolutionary improvement in the field of reconstructive surgery. Virtual surgical planning (VSP) and threedimensional (3D) bio-printing incorporating computer-aided design and computer-aided modeling is a promising tech in modern head and neck reconstruction. This recent innovation is more polished regarding initiation of patient-customized models, pre-bent plates, and osteotomy guides which further increase surgical precision, improve operative efficiency, ensure proper wound healing, shorten operative time, reduce operative cost, and decrease morbidities. This review focuses on the virtual surgical planning and 3D bio-printing technologies to evaluate their efficiency of qualitative and quantitative outcomes of resection and reconstruction of mandible in head-neck cancer using fibular graft.

Use of CAD-based pre-bent implants reduces theatre time in orbital floor reconstruction: results of a prospective study.

In this prospective study we evaluated the duration of insertion and the accuracy of fitting of computer-aided design (CAD)-based pre-bent orbital floor plates compared with non-preformed orbital plates in reconstruction of the orbital floor. Thirty-six patients with unilateral fractures of the orbital floor were included; pre-bent plates were used in 25 and non-preformed plates in 11. Preoperative computed tomography (CT) scans were used for CAD of individualised implants. The anatomy of the affected orbit was virtually reconstructed "slice by slice". Individually pre-bent plates were generated using a stereolithographic model of the reconstructed orbit. The mean (SD) duration of insertion was significantly reduced when pre-bent orbital plates were used (5.5 (5.4) min) compared with non-preformed meshes (11.1 (7.7) min). The congruence of pre-bent plates to the infraorbital rim did not differ from that of non-preformed plates. The accuracy of fit was rated as "accurate" in 24 cases. CAD-based individualised titanium meshes reduce theatre time compared with non-preformed orbital plates. Our results confirm the efficacy of CAD-based pre-bent plates in reconstruction of the orbital floor.

Pararectus approach combined with three-dimensional printing for anterior plate fixation of sacral fractures

BackgroundSurgical treatment of sacral fractures is difficult, both for reduction and stabilization. Traditional surgical reduction and internal fixation require a long duration of operation leading to extra blood loss, extensive tissue damage, and increased risk of post-operation complications. The purpose of this study was to evaluate the feasibility of a minimally invasive technique that could be more effective, more tissue sparing, and lead to less bleeding. We hypothesized that a Pararectus approach for anterior fixation of unstable sacral fractures would be reliable and more advantageous and significantly improve the outcome of sacral fracture repair. MethodsTwelve patients with unstable sacral fractures were recruited and examined by CT scanning. A 3D model of each sacral fracture was reconstructed. The computer-assisted 3D image of the reduced pelvis was 3D printed for surgery simulation and plate pre-bending. All cases were treated operatively with the anterior anatomical reduction and internal fixation via a minimally invasive Pararectus approach. VAS, Matta, and Majeed scores were used to evaluate outcomes of the operation. ResultsPre-operations were consistent with the actual surgeries in all cases. The pre-bent plates had an anatomical shape specifically fit to the individual pelvis without further adjustment at the time of surgery, and fracture reductions were significantly improved with little invasive tissue damage. The average operation time was 110 min. The intraoperative blood loss and incision length averaged 695 ml and 6.7 cm, respectively. A high percentage of all cases achieved a diaplasis with an excellent or good score according to the Matta and Majeed standards (83.33% and 91.67%, respectively).All patients achieved clinical healing with an average healing time of 8 weeks. Conclusion3D printing-assisted anterior fixation of unstable sacral fractures via a minimally invasive Pararectus approach is feasible. This new surgical strategy minimizes trauma damage and bleeding and produces satisfactory reduction and therapeutic efficacy.

Three dimensional accuracy of mandibular reconstruction by pre-bent reconstruction plate using intra oral versus extra oral approaches following mandibular resection in patients with extensive ameloblastoma

Purpose: This prospective study aimed to compare the intraoral placement of the pre-bent reconstruction plate with that inserted via the extraoral approach, to evaluate their impact on the three-dimensional (3D) position of the proximal segment Patients and methods: Patients were divided into two equal groups. In group 1, the mandible was reconstructed with a pre-bent reconstruction plate via an intraoral approach. In group 2, an extraoral approach was used. The primary outcome variables were the need for intraoperative plate readjustment, the time needed for plate insertion, total operation time, difficulties encountered during surgery, and the postoperative stability of the proximal segment. Distances between corresponding anatomical landmarks on the mandibular angle and condyle as well as the intercondylar angle (ICA) and B`XC angle, were measured. The difference between the pre- and postoperative measurements was used to evaluate the reconstruction accuracy. Results: Thirty patients were enrolled in this study. In group 1, four plates required minor readjustment. In group 2, only two cases required re-adaptation. The intraoral insertion of the pre-bent plates revealed a decrease in the linear measurements, resulting in mandibular compression. On contrary, the extraoral approach showed increase in the measurements, resulting in widening of the mandible. However, this width difference was statistically insignificant. Concerning the ICA and B`XC angle, no significant difference could be ascertained between the two groups. Conclusion: Intraoral approach is more conservative procedure, thereby achieving the best esthetic outcomes and resulting in a more accurate 3D mandibular reconstruction.

Outcomes of using pre-bent reconstruction plates in mandibular reconstruction

Outcomes of using pre-bent reconstruction plates in mandibular reconstruction

Medial minimally invasive helical plate osteosynthesis of the distal femur – a new technique

IntroductionThe goal of this study was to evaluate distal femoral minimally invasive plate osteosynthesis (MIPO) from a distal medial approach by use of a pre-bent helical implant. Material & MethodsA total of 18 lower extremities was evaluated. A 29.6 cm steel plate was constructed and pre-bent on bone specimens with a torsion of 55.7° A 5 cm incision was performed from the tip of the medial epicondyle alongside its centre in a proximal direction. The medial border of the vastus medialis was retracted anteriorly. The level of the proximal skin incision was determined using the length of the pre-bent plates. The proximal incision was performed at a length of 4 cm at the described height at a line between the lateral epicondyle and the tip of the greater trochanter. A raspatory was advanced beneath the vastus medialis in a proximal direction to create an extraperiosteal tunnel for plate insertion. The plate was fixed to the bone at its proximal and distal portion via screws. Following dissection, the distance between the nearest perforator to the proximal plate end was evaluated. The vertical distances between the medial border of the plate and the femoral artery and femoral nerve were measured at the level of the proximal plate end and at the level of the proximal margin of the vastoadductor membrane. ResultsThe most proximal perforating artery was located at a mean distance of 20.15 mm starting from the proximal plate margin. The mean interval between the medial border of the plate at the level of its proximal tip and the femoral artery was 51.9 mm. The average distance between the femoral nerve and the medial border of the proximal part of the plate was 42.3 mm. Regarding the interval between the medial border of the plate and the femoral artery, this was at a mean of 40.5 mm at the level of the proximal margin of the vastoadductor membrane. During dissection, none of the specimens showed any lesions of the adjacent anatomical characteristics. ConclusionOur results indicate MIPO of the distal femur from a medial approach as a safe technique.

Clinical efficacy of peek patient-specific implants in orbital reconstruction

PurposeTo assess the clinical efficacy of custom made PEEK patient-specific implants in treatment of orbital wall defects. MethodsForty-five patients with unilateral post-traumatic orbital wall defects were enrolled in the study. They underwent subsequent reconstructive procedures using PEEK patient-specific implants (PSI) or pre-bent titanium plates. All the patients were examined with the standardized algorithm, including local status examination, vision assessment and computer tomography (CT) with measurements of the orbital volume. A comparative analysis of the treatment outcomes in two groups of patients (pre-bent plates/PSI) was performed. ResultsThe study findings show an absence of any postoperative infection, inflamation or decreased visual acuity in either group. In PSI group, diplopia after surgery was absent in 82.1% of patients versus 70.6% of controls. The mean duration of surgery was 54.25 ± 16.8 min with PSI application and 82.9 ± 10.8 min with pre-bent plates. The mean difference between the intact and damaged orbital volume was 1.9 ± 1.4 cm3 in the control group versus 0.74 ± 0.6 cm3 in PSI group (р<0.05). ConclusionPEEK PSI demonstrated higher clinical efficacy in comparison to pre-bent plates in orbital wall reconstruction especially in restoring the volume and shape of the damaged orbit.

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.