RapidSplint: virtual splint generation for orthognathic surgery – results of a pilot series

Abstract

BackgroundWithin the domain of craniomaxillofacial surgery, orthognathic surgery is a special field dedicated to the correction of dentofacial anomalies resulting from skeletal malocclusion. Generally, in such cases, an interdisciplinary orthodontic and surgical treatment approach is required. After initial orthodontic alignment of the dental arches, skeletal discrepancies of the jaws can be corrected by distinct surgical strategies and procedures in order to achieve correct occlusal relations, as well as facial balance and harmony within individualized treatment concepts. To transfer the preoperative surgical planning and reposition the mobilized dental arches with optimal occlusal relations, surgical splints are typically used. For this purpose, different strategies have been described which use one or more splints. Traditionally, these splints are manufactured by a dental technician based on patient-specific dental casts; however, computer-assisted technologies have gained increasing importance with respect to preoperative planning and its subsequent surgical transfer.Methods: In a pilot study of 10 patients undergoing orthognathic corrections by a one-splint strategy, two final occlusal splints were produced for each patient and compared with respect to their clinical usability. One splint was manufactured in the traditional way by a dental technician according to the preoperative surgical planning. After performing a CBCT scan of the patient’s dental casts, a second splint was designed virtually by an engineer and surgeon working together, according to the desired final occlusion. For this purpose, RapidSplint®, a custom-made software platform, was used. After post-processing and conversion of the datasets into .stl files, the splints were fabricated by the PolyJet procedure using photo polymerization. During surgery, both splints were inserted after mobilization of the dental arches then compared with respect to their clinical usability according to the occlusal fitting.ResultsUsing the workflow described above, virtual splints could be designed and manufactured for all patients in this pilot study. Eight of 10 virtual splints could be used clinically to achieve and maintain final occlusion after orthognathic surgery. In two cases virtual splints were not usable due to insufficient occlusal fitting, and even two of the traditional splints were not clinically usable. In five patients where both types of splints were available, their occlusal fitting was assessed as being equivalent, and in one case the virtual splint showed even better occlusal fitting than the traditional splint. In one case where no traditional splint was available, the virtual splint proved to be helpful in achieving the final occlusion.ConclusionsIn this pilot study it was demonstrated that clinically usable splints for orthognathic surgery can be produced by computer-assisted technology. Virtual splint design was realized by RapidSplint®, an in-house software platform which might contribute in future to shorten preoperative workflows fo...

Validation of a fibula graft cutting guide for mandibular reconstruction: experiment with rapid prototyping mandible model

“…Further studies should investigate various error factors to determine how to modify the method for clinical applications with the use of various surgical guides, and for integration with an auxiliary navigation method. [9][10][11] In conclusion, our results are based on experiments with RP models of mandibles and fibulas. These RP mandibles were reconstructed with fibulas that were cut with either a surgical template guide or a manual method.…”

Is patient-specific pre-operative preparation feasible in a clinical environment? A systematic review and meta-analysis

“…Of fourty-nine studies matching the inclusion criteria, 37 were case-series, 10 were non-randomised comparative trials and 2 randomised controlled trials. The most common surgical specialities in the included studies were maxillofacial surgery (n ¼ 16) [7,8,[14][15][16][17][18][19][20][21][22][23][24][25][26][27] and orthopaedics (n ¼ 15) [9, 10, 28-40] ( Table 1).…”

“…It should also be noted that many authors propose PS preoperative preparation for "difficult" cases (e.g. severely comminuted fractures or cranial base tumours [49] Complete clearance of stones 5/8 (62.5%) -Mucosal perforation 1/8 (12.5%) Gateno et al [20] Deformities corrected at 6 week f/u Xia et al [27] NIP Hislop et al [44] Successful operations (0% residual vessel stenosis) 3/5 (60%) Lu et al [53] 77.8% improvement in symptoms at 9 months f/u No complications Ng et al [47] Complete resection 23/23 (100%) -4.3% had additional neurological deficit post-operatively -1/23 severely disabled due to post-operative complications Dhanda et al [17] 1.43 cm average improvement in mouth openining Fornaro et al [29] Anatomic or satisfactory reduction of fracture 7/7 (100%) -No serious complications Qiu et al [43] Total tumour resection 33/45 (73.3%) -Decrease >10% of effective fibre of pyramidal tract 7/45 (15.6%) Dong et al [28] Resection margins free of tumour in all cases Essig et al [18] 2/3 good results Ferrari et al [48] No Information Provided (NIP) Hu et al [31] NIP Tepper et al [7] NIP Derand et al [16] Surgeons' opinion: Good correlation of plan and surgical steps Calculated reduction in operation time 30min Kanzaki et al [54] No conversion to open Margins free of cancer 3 complicationsprolonged air leak, needed pleurodesis Kerens et al [33] All guides fitted well during real surgery Good stability in all cases at 6 weeks f/u No complications Nam et al [9] Good alignment of lower limb for: CAS: 92.7% -PCS:70.7% Scolozzi [25] Satisfactory reconstruction 2/2 0 complications Shen et al [37] Satisfactory or anatomical reduction in 5/6 (83.3%) cases -No complications (0%) Willaert et al [45] NIP Adolphs et al [14] NIP Desender et al [41] NIP Hsu et al [21] NIP Issa et al [32] No complications Mandel et al [57] NIP Pietsch et al [35] Satisfactory outcome (overall axis within 3 o ) 47/51 (94%) Schweizer et al [36] Improvement of wrist ROM at 1 year f/u Increase of wrist strength by 10% on average No complications (no ...…”

Three-dimensional printed final occlusal splint for orthognathic surgery: design and validation

“…Furthermore, the occlusion cast was used to test the accuracy of the final splint as the gold standard reference instead of the conventional splint, as reported in previous studies. 3,7 The routinely applied clinical protocol was used as standard. This consisted of fixing the occlusion cast through the The same occlusion cast scanned with the high-dose patient CBCT protocol, as described in Table 1.…”

“…[2][3][4][5] The main advantages of 3D planning include the production of a virtual skull and dentition and the direct production of digital and subsequent physical splints, 6 leading to more accurate planning, time savings, and better results. Previous research has investigated the accuracy of final digital splints in smallscale validation studies with a maximum of 10 cases, 3,6,7 or simply through proof of concept. 8 Comparisons were made to conventional manual splints and considered as the ground truth, which is not entirely correct.…”