Patricia Stoor

Rapid prototyped patient specific implants for reconstruction of orbital wall defects

Defects of orbital walls can be reconstructed using implants. The authors report a safe and accurate method to reconstruct bone defects in the orbital area using patient specific implants. A detailed process description of computer aided design (CAD) reconstructive surgery (CRS) is introduced in this prospective study. The 3D volumetric virtual implant was design using MSCT data and PTCProEngineer™ 3D software. The intact orbital cavity of twelve patients was mirrored to the injured side. Specific ledges steered the implant into correct place. Postoperatively the position was assessed using image fusion. One implant (8%) was rejected due to chemical impurities, two (16%) had a false shape due to incorrect CAD. Data of thin bone did not transfer correctly to CAD and resulted in error. One implant (8%) was placed incorrectly. Duration of the CRS was in average 1.17 h, correspondingly 1.57 h using intraoperative bending technique. The CRS process has several critical stages, which are related to converting data and to incompatibility between software. The CRS process has several steps that need further studies. The data of thin bone may be lost and disturb an otherwise very precise technique. The risk of incorporating impurities into the implant must be carefully controlled.

Increase in VEGF secretion from human fibroblast cells by bioactive glass S53P4 to stimulate angiogenesis in bone

Bioactive glasses (BAGs) are being investigated for the repair and reconstruction of bone defects, as they exhibit osteoconductive and osteostimulatory potential. However, successful bone regeneration requires also the neovascularization of the construct which is, among other factors, guided by vascular endothelial growth factor (VEGF). In this study, BAG S53P4 (53% SiO2 , 23% Na2 O, 20% CaO, 4% P2 O5 ) is investigated in relation to VEGF-release and response of fibroblast cells. Human CD-18CO fibroblasts were cultivated in contact with different granules of different sizes (0.5-0.8 mm, 1.0-2.0 mm, and 2.0-3.15 mm) and at different concentrations (0-1 wt/vol % of BAG) for 72 h. The analysis of morphology revealed no toxic effect for all granule sizes and concentrations. Compared with the reference, lactate dehydrogenase-activity of CCD-18CO cells increased in contact with BAG samples. The VEGF release from CCD-18CO fibroblasts cultured on different granule sizes and at different concentrations after 72 h of incubation was quantified. It was found that particles of 0.5-0.8 mm and 1.0-2.0 mm in size enhanced VEGF release, whereas BAG particle sizes of 2.0-3.15 mm led to inhibition of VEGF release. The results are relevant to understand the influence of the particle size and concentration of BAG S53P4 on VEGF expression and neovascularization.

Anti-tumor necrosis factor treatment in cherubism--clinical, radiological and histological findings in two children.

Cherubism is a rare and disfiguring genetic disorder with excessive bone resorption and multilocular lesions in the mandible and/or maxilla. The disease-causing gain-of-function mutations in the SH3-binding protein 2 (SH3BP2) gene result in increased myeloid cell responses to macrophage colony stimulating factor and RANK ligand, formation of hyperactive osteoclasts (giant cells), and hyper-reactive macrophages that produce excessive amounts of the inflammatory cytokine tumor necrosis factor α (TNF-α). Recent findings in the cherubism mouse model suggest that TNF-α plays a major role in disease pathogenesis and that removal of TNF-α prevents development of the bone phenotype. We treated two children with cherubism with the TNF-α antagonist adalimumab for approximately 2.5 years and collected extensive clinical, radiological and histological follow-up data during the treatment. Histologically the treatment resulted in a significant reduction in the number of multinucleated giant cells and TNF-α staining positivity in both patients. As evaluated by computed tomography and magnetic resonance imaging, the lesions in Patient 1 showed either moderate enlargement (mandibular symphysis) or remained stable (mandibular rami and body, the maxilla). In Patient 2, the lesions in mandibular symphysis showed enlargement during the first 8 months of treatment, and thereafter the lesions remained unchanged. Bone formation and resorption markers remained unaffected. The treatment was well tolerated. Based on our findings, TNF-α antagonist may decrease the formation of pathogenic giant cells, but does not result in lesion regression or prevent lesion expansion in active cherubism. TNF-α modulator treatment thus does not appear to provide sufficient amelioration for patients suffering from cherubism.

Rapid prototyping modelling in oral and maxillofacial surgery: A two year retrospective study

Background The use of rapid prototyping (RP) models in medicine to construct bony models is increasing. Material and Methods The aim of the study was to evaluate retrospectively the indication for the use of RP models in oral and maxillofacial surgery at Helsinki University Central Hospital during 2009-2010. Also, the used computed tomography (CT) examination – multislice CT (MSCT) or cone beam CT (CBCT) - method was evaluated. Results In total 114 RP models were fabricated for 102 patients. The mean age of the patients at the time of the production of the model was 50.4 years. The indications for the modelling included malignant lesions (29%), secondary reconstruction (25%), prosthodontic treatment (22%), orthognathic surgery or asymmetry (13%), benign lesions (8%), and TMJ disorders (4%). MSCT examination was used in 92 and CBCT examination in 22 cases. Most of the models (75%) were conventional hard tissue models. Models with colored tumour or other structure(s) of interest were ordered in 24%. Two out of the 114 models were soft tissue models. Conclusions The main benefit of the models was in treatment planning and in connection with the production of pre-bent plates or custom made implants. The RP models both facilitate and improve treatment planning and intraoperative efficiency. Key words:Rapid prototyping, radiology, computed tomography, cone beam computed tomography.

The use of anatomically drop-shaped bioactive glass S53P4 implants in the reconstruction of orbital floor fractures—A prospective long-term follow-up study

An isolated fracture of the orbital floor needs reconstruction if there is a clear herniation of adipose tissue or of the rectus inferior muscle into the maxillary sinus. A prospective study was carried out treating 20 patients with an isolated blow-out fracture of the orbital floor or with a combined zygomatico-orbito-maxillary complex fracture, using a newly designed anatomically drop-shaped implants made of bioactive glass (BAG) S53P4. Computed tomography (CT) was performed immediately postoperatively to confirm the correct position of the plate. The patients were followed up for an average of 32 months clinically and radiologically with magnetic resonance imaging (MRI) for an average of 31 months. None of the patients had any signs of complications related to the implant and the clinical outcome was very good. None of the patients had persisting diplopia. The level of the pupillas was normal in 15 of 20 patients. Minor hypo-ophthalmos ranging from 0.5 to 1.0 mm was observed in three patients, and moderate hypo-ophthalmos of 2.0 mm was seen in one patient. Hyperophthalmos of 1.0 mm was seen in one patient. Minor enophthalmos on the operated side ranging from 0.5 to 1.0 mm was seen in eight patients. Mild to moderate paraesthesia of the infraorbital nerve was observed in six patients. The immediate postoperative CT and the long term follow-up MRI revealed that the drop-shaped BAG implants retained their correct position in the orbital floor and did not show any evidence of losing their original shape or material resorption. No adverse tissue reaction was associated with the material. Due to the anatomical drop shape, the implants could successfully maintain the orbital volume and compensate for the retrobulbar adipose tissue atrophy.

The use of patient-specific implants in orthognathic surgery: A series of 30 mandible sagittal split osteotomy patients

PURPOSE Virtual surgery combined with patient-specific saw and drill guides and osteosynthesis materials are rapidly spreading from reconstructive surgery to orthognathic surgery. Most commercial partners are already providing computer-aided design and computer-aided manufacture (CAD/CAM) wafers and patient-specific saw guides. Clear benefits have been demonstrated for custom-made drill guides combined with individually designed three-dimensional (3D) printed patient-specific implants (PSI) as a reposition and fixation system in Le Fort I osteotomy. MATERIALS AND METHODS We treated 30 patients who underwent bilateral sagittal split osteotomy (BSSO) due to class II dento-skeletal deformities with the additional use of drill guides combined with PSI as a fixation and positioning system. RESULTS The PSIs fitted bilaterally with total precision in 11 of the 30 patients. In 17 patients, the PSIs were used with some modifications. In 2 of 30 patients, the PSIs could not be used as a fixation due to misfit. CONCLUSION Due to unpredictable fitting, the use of PSIs with drill guides alone in BSSO without wafers cannot be recommended. Further studies are needed to evaluate the interfering parts, which seem to be related to condylar positioning and bony interferences at the osteotomy sites.

Rapid prototyped patient specific guiding implants in critical mandibular reconstruction

Large tumours of the mandible need immediate reconstruction to provide continuity of the mandible, satisfactory function of the jaw, as well as an acceptable aesthetic outcome. In this prospective study we described the immediate reconstruction of the mandible using computer aided design and 15 rapid prototyped patient specific implants (PSI) in 14 patients suffering from benign or malignant tumours demanding continuity resection of the mandible. The scaffold PSI was filled with β-tricalcium phosphate granules and autologous bone. Microvascular reconstruction was additionally needed in 12/15 cases. The clinical follow up was on average 33 months and the radiological follow up was on average 21 months. In nine cases the healing was uneventful. One patient lost the microvascular flap during the first postoperative week and one patient needed a revision due to perforation of the mucosa at the site of the PSI. Four patients had a major complication due to perforation of the mucosa leading to infection, which resulted in the total or partial removal of the PSI. The PSI seems to be a promising solution for treatment of patients demanding large reconstruction after mandible resection. The benefits are decreased rate of donor site complications and more accurate and prompt surgical procedure.

Osteotomy Site Grafting in Bilateral Sagittal Split Surgery With Bioactive Glass S53p4 for Skeletal Stability

Abstract In orthognathic surgery, the aim of the treatment is to achieve a good occlusion and a satisfying aesthetic outcome. In large mandibular advancements insufficient healing at the mandibular inferior border may lead to loss of support for the overlaying tissue at the osteotomy site. Augmentation can be performed to improve stability, bone regeneration, and the aesthetic outcome. The purpose of this prospective clinical study was to evaluate the use of a novel material for this indication; granules of the antibacterial, osteoconductive, and slowly resorbing bioactive glass S53P4 as filling material in large mandibular advancement in bilateral sagittal split osteotomies. The authors treated 25 patients who underwent bilateral sagittal split osteotomies due to class II dentoskeletal deformities. The mandibular osteotomy site defects (8–15 mm) were augmented with bioactive glass S53P4. The average clinical follow-up was 33 months and the average radiological follow-up with cone beam computerized tomography was 24 months. The clinical and radiological results were good with regard to healing, bone regeneration, and stability of the osteotomy sites. The recontouring of the inferior mandibular border provided a good soft tissue support followed by an excellent aesthetic outcome in 96% of the osteotomy sites. The occlusion was stable in 88% of the patients. The authors’ results show that bioactive glass S53P4 is a safe grafting material for osteotomy site defects in significant mandibular advancements with reliable bone regeneration, providing long-term stability at the osteotomy site and at the inferior mandibular border.

Regeneration of Cystic Bone Cavities and Bone Defects With Bioactive Glass S53p4 in the Upper and Lower Jaws

Abstract Cysts and tumors are common lesions in the jaws. To be able to retain a good volume of the alveolar ridge during healing as well as strengthening the angle and body of the mandible and provide an instant improved support for adjacent teeth, reliable long-term bone regeneration is needed. The purpose of this prospective study was to promote bone regeneration by filling bony defects in the upper or lower jaw with granules of the bioactive glass S53P4 (BAG), which have osteostimulative and antimicrobial properties. The authors treated 20 patients (21 defects) surgically; benign tumors, cysts, or infection related to impacted teeth in the maxilla or mandible. The tumor or cyst was removed or enucleated and thorough cleaning of the infected area was performed. The bone cavity was filled with granules of the BAG S53P4 despite signs of chronic infection in the area at the time of surgery. The patients were followed up for an average of 34 months clinically and with cone beam computerized tomography for 28 months. In 20 defects the final outcome was successful. Despite infection at the time of surgery in 65% of the patients, no material associated infection was seen during the follow-up. The BAG S53P4 granules were radiologically remodeled into bone after 2 years follow-up. The use of granules of the BAG S53P4 in the treatment of large bone defects provides infection-free reliable bone regeneration despite chronic infection at the time of surgery, which improves the prognosis of adjacent teeth.

Comparison between patient specific implants and conventional mini-plates in Le Fort I osteotomy with regard to infections: No differences in up to 3-year follow-up

Individually designed osteotomies and milled or printed patient-specific osteosynthesis materials are rapidly becoming a standard in maxillofacial reconstructive surgery. The benefits of using patient-specific implants (PSIs) in orthognathic surgery are especially clear in complex cases, and for this reason they are rapidly becoming common practice. We have earlier reported the benefits related to the use of PSIs as reposition and fixation system in Le Fort I osteotomy. The aim of this study was to compare complications associated with fixation with PSIs (31 patients) versus conventional mini-plates (37 patients) in Le Fort I osteotomy. No statistically significant differences in infection, reoperations or soft tissue problems were observed between the two systems used. Interestingly, three of the 37 patients in the mini-plate group underwent reoperation due to insufficient advancement or malocclusion, whereas none of the patients in the PSI group needed reoperation. In conclusion, PSIs are reliable for use in orthognathic surgery, with no signs of infection associated complications.