Risk factors for post-operative complications after procedures for autologous bone augmentation from different donor sites.

AIM: The aim of this study has been to identify risk factors for post-operative complications after grafting bone from different donor sites prior to implant placement. MATERIAL AND METHODS: The study encompassed 279 patients who underwent autologous bone augmentations in a 2-stage procedure, harvested from three intraoral and one extraoral donor sites, as well as sinus floor elevations prior to implant placement. The following complications were recorded: soft tissue dehiscence; wound infection; bone graft exposure; sensory disturbance; sinusitis symptoms; haemorrhage; graft failure; implant failure. Complications were correlated with: patient age; smoking status; history of gingivitis/periodontitis; cause of tooth loss; jaw area; dental situation; sinus membrane perforation; surgeons' experience. RESULTS: 279 patients underwent 456 augmentation procedures, involving 546 sites. 436 grafts were successful. 525 implants were inserted into 436 augmented sites in 273 patients. 20 grafts were lost due to complications. 2 implants were removed before prosthetic restoration. 2 implants were lost within 2 years after placement. Age (p = 0.0009, Odds Ratio = 2.44), smoking (p < 0.0001, Odds Ratio = 2.47), Approximal Plaque Index (p < 0.0001, Odds Ratio = 6.64), Sulcus Bleeding Index (p < 0.0001, Odds Ratio = 39.06) and dental situation (p < 0.0001) were significantly correlated with higher post-operative morbidity. Cause of tooth loss (p = 0.7399), jaw area (p = 0.6725), sinus membrane perforation (p = 0.0762) and surgeons' experience (p = 0.0939) did not influence complication rates. CONCLUSIONS: Patients over 40 years old, smokers, a history of periodontitis, and augmentation in tooth gaps involving more than one tooth represent a significantly increased risk of there being post-operative complications compared with patients younger than 40 years old, non-smokers, no history of periodontitis, only a single-tooth gap, or free-end arch situations.

Tomographic osteometry of the zygomatic bone applied to traumatology of facial bones: Preliminary retrospective study of zygomatic summit in 28 patients.

BACKGROUND: The available referential measures defining the zygomatic bone morphology are adequate enough for full determination of the zygoma positioning, especially for trauma surgery, but osteometric analysis of the zygoma positioning based on tomographic examinations could be useful in peroperative and postoperative imaging. In this study, we propose referential measures, taking into account the morphology and the symmetry of the zygoma. In addition, the reliability and reproducibility are considered. METHODS: Thirty normal computed tomography (CT) scans were used to establish the referential measures. The study involved preoperative imaging (27 CT and 1 cone beam CT [CBCT] scan), and postoperative imaging (6 CT and 22 CBCT scans) pertaining to 28 patients, showing a unilateral zygomatic fracture. In a precisely chosen axial cut in the orbito-meatal plane, 3 referential data were defined: namely, S, denoting the distance of the zygoma summit; αS, representing the angle between the summit and the symmetry axis passing through the clivus; and αZ, corresponding to the morphologic angle. RESULTS: The 3 referential measures S, αS, and αZ are reliable and reproducible by CT and CBCT examination. Those parameters can be used to evaluate the zygomatic symmetry. The postoperative asymmetries arise from an erroneous recovery of S, which was statistically significant at p = 0.0216. CONCLUSION: On a single optimized axial cut, the new referential measures are useful and effective in preoperative and postoperative assessment of the residual bone asymmetries. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.

The use of zygomatic implants for the retention of nasal prosthesis following rhinectomy: the Morriston experience.

Reconstruction and rehabilitation following rhinectomy remains controversial and presents a complex problem. Although reconstruction with local and microvascular flaps is a valid option, the aesthetic results may not always be satisfactory. The aesthetic results achieved with a nasal prosthesis are excellent; however patient acceptance relies on a secure method of retention. The technique used and results obtained in a large series of patients undergoing rhinectomy and receiving zygomatic implants for the retention of a nasal prosthesis are described here. A total of 56 zygomatic implants (28 patients) were placed, providing excellent retention and durability with the loss of only one implant in 15 years.

Treatment of extreme maxillary atrophy with Zygoma implants.

The implant-prosthetic rehabilitation of severe maxillary atrophy often requires difficult bone grafting techniques or microvascularized flaps with long healing time and severe discomfort for the patients. An alternative is represented by the use of particular thick bone areas like "zygomatic buttresses" that are away from the alveolar ridge but they are good for anchoring implants. From 2008, 31 patients, aged between 52 and 82 years, with severe maxillary atrophy, have been rehabilitated using zygomatic implant (Zygoma Brånemark System®) and conventional implants (4 mm of diameter and a length of 13 to 15 mm); a total of 152 implants were inserted, 78 Zygoma implants and 74 conventional implants in the premaxilla. As dictated by our protocol, all of them were followed by immediate prosthetic loading. Follow-up ranges from 20 months to 5 years. Two Zygoma implants failed out of 78 fixtures inserted with a success rate of around 98%. No failure of conventional implants. Two patients developed a postoperative sinusitis; one case healed only after endoscopically guided medium meatal antrostomy. In one case the removal and reinsertion of one Zygoma implant was necessary. We observed two cases of temporary zygomatic hypoesthesia, two cases of persistent oedema for three weeks and one case of facial postoperative haematoma; all of them spontaneously solved after a few weeks. Our results are in agreement with the Literature and lead to the conclusion that the use of Zygoma implants is a reproducible and predictable alternative to bone grafts, with the advantage of a considerable saving of time.

Found in space: computer-assisted orthognathic alignment of a total face allograft in six degrees of freedom.

PURPOSE: Full facial osteomyocutaneous transplantation requires correct 3-dimensional (3D) alignment of donor osseous structures to a new cranial base with minimal reference points and 6 degrees of potential movement. We investigated whether computer-assisted design and manufacturing (CAD/CAM) could enable accurate placement of the facial skeleton. MATERIALS AND METHODS: A prospective single-cohort study of Le Fort III-based maxillary-mandibular segment allotransplantation was performed in 5 cadaver pairs and 1 clinical pair. The osteotomies were modeled using computed tomography (CT) data and 3D modeling software and then translated to the donor-recipient pairs using surgical navigation and osteotomy cutting guides. The predicted values were calculated about all rotational axes (pitch, yaw, and roll) and along all translational axes (vertical, horizontal, and anteroposterior) and used as the independent variable. The primary outcome variable of the actual postoperative CT values was compared for fidelity to the prediction using the intraclass correlation coefficient (ICC). The similarity to the donor versus recipient values was calculated as a secondary independent variable, and both predicted and actual measurements were compared with it as a percentage. RESULTS: The postoperative fidelity to the plan was adequate to excellent (ICC 0.520 to 0.975) with the exception of lateral translation (2.94 ± 1.31 mm predicted left vs 3.92 ± 2.17 mm right actual displacement; ICC 0.243). The predicted and actual values were not consistently skewed toward the donor or recipient values. CONCLUSIONS: We have demonstrated a novel application of CAD/CAM that enables orthognathic alignment of a maxillary-mandibular segment to a new cranial base. Quantification of the alignment in all 6 degrees of freedom delivers precise control compared with the planned changes and allows postoperative quality control.

Alveolar zygomatic buttress: A new donor site for limited preimplant augmentation procedures.

PURPOSE: Augmentation of anterior maxillary alveolar bone defects before placement of endosseous implants still poses a clinical challenge. Previous traumatic loss of upper anterior teeth is often concomitant with significant bone loss. The aim of augmentation is to reconstitute as far as possible the original hard tissue contour. This is a prerequisite for later optimal positioning of the dental implants in accordance with prosthodontic and functional principles. MATERIALS AND METHODS: This article describes a new method for the reconstruction of small anterior maxillary alveolar bone defects using donor bone from the zygomatic buttress region. RESULTS: This region provides harvested bone with a natural convex shape, which is ideally suited for the anterior alveolar process region. Later fibrous tissue transplantation to provide more anterior projection to the anterior dental area is also avoided. CONCLUSION: Bone harvesting was done with the piezoelectric device, which avoids trauma to the mucosal membrane of the maxillary sinus.

Maxillary sinus and ridge augmentations using a surface-derived autogenous bone graft.

PURPOSE: The purpose of this article is to describe a new technique and the anatomic sites for cutting and harvesting bone for grafting applications. A handheld instrument is described that cuts and collects thin shavings of bone from cortical surfaces. MATERIALS AND METHODS: This study included 193 consecutive patients who needed bone augmentation and simultaneous implant placement in the severely atrophic posterior maxilla and in the anterior maxilla with acquired defect of alveolar bone as a result of local trauma. A total of 477 implants were placed. Clinical criteria for evaluation at time of implant exposure included stability in all directions, crestal bone resorption, and any reported pain of discomfort. RESULTS: There were no failures of the anterior maxilla group, and no signs of bone resorption were noted at the second stage surgery or during the follow-up. During initial and late healing, there was no dehiscence of the soft tissue flaps and no membranes were exposed. Core biopsies typically showed immature, newly formed bone and, on average, 27% to 36% vital bone. CONCLUSION: From this research, it appears that excellent implant success rates can be achieved in grafted sinuses or ridges when a locally harvested autogenous bone graft with a ribbon geometry is used.

Reconstrucción de reborde orbitario y piso de órbita con injerto de hueso del arco cigomático, placas Lactosorb y malla de titanio / Reconstruction of orbital ridge and floor with cygomatic bone graft, Lactosorb plates and titanium mesh

El motivo de la presentación es poner en consideración una técnica quirúrgica destinada a la reconstrucción del piso de la órbita y el reborde orbitario con un injerto de hueso y fijación rígida que fue resecado debido a un tumor que afectaba la totalidad del maxilar superior del lado derecho yla zona orbitaria del mismo lado. La reconstrucción post-exéresis de tumores en el área maxilofacial es uno de los desafíos más importantes que se le plantean al cirujano. Actualmente, se cuenta con un conjunto de materiales de reemplazo de probada eficacia que, asociados con los injertos de tejido óseo, brindan una excelente alternativa para la reconstrucción

The influence of bony architecture on fixed membranous bone graft survival.

The aim of this study was to examine the influence of membranous bone graft architecture on graft survival. Eighteen adult New Zealand rabbits underwent full-thickness harvesting of their zygoma, which was then divided into two parts, resulting in a wider, thicker anterior graft and a tapered posterior graft. The grafts were then rigidly fixed, one to each nasal bone, using titanium lag screws. On postgrafting days 15 and 45, 3 animals each were killed. The remaining 12 animals were killed on day 90. The graft, graft-host interface, and contralateral zygoma were assessed volumetrically, histologically (nondecalcified), and stereologically. Volumetrically, the anterior (thicker, wider) grafts demonstrated 100% survival while the posterior (thinner, more narrow) grafts demonstrated 80% survival (p = 0.004). Histologically, the anterior grafts demonstrated less resorption and porosity and greater labeling activity. At the graft-host interface, the anterior grafts exhibited a 2.5-fold increase in full incorporation of the grafts, and the posterior grafts had almost twice the incidence of nonincorporation. Stereological measurements, including interlabel width (20.3 microns anteriorly, 18.9 microns posteriorly), confirmed the enhanced survival of the anterior grafts. Using multiple forms of analyses, this study demonstrates that membranous bone graft architecture influences graft survival. To assist in understanding these differences, we also analyzed the normal contralateral zygoma. While the anterior and posterior halves had a relatively constant amount of bicortical bone, the thicker grafts had a proportionally greater trabecular component (i.e., increased diploë-to-cortical ratio). In the rabbit model, differences in membranous bone thickness imply differences in the cancellous portion of the graft, thereby influencing ultimate graft survival.

The early revascularization of membranous bone.

The experimental finding that membranous onlay bone grafts maintain volume and viability to a greater extent than do endochondral grafts may be related to the more rapid vascularization of membranous bone. Microangiographic techniques were used to study the rates of vascularization of membranous and endochondral bone grafts in adult white New Zealand rabbits at 1, 3, 7, 14, and 21 days after bone grafting. Vascularization patterns were quantified microscopically using a modified point-counting technique. At 3 days, membranous bone grafts demonstrated vessel ingrowth from both soft tissue and host bone. Little ingrowth was seen in endochondral grafts. By day 7, 2.5 vessels per square were identified entering membranous grafts, while an average of 0.6 vessels per square were counted for endochondral bone grafts. At day 14, there was an average of greater than 20 vessels per square for membranous grafts versus 1.8 for their endochondral counterparts. At 21 days, the endochondral grafts demonstrated persistent avascular central areas not seen in membranous grafts. Membranous onlay bone grafts in the rabbit are more rapidly vascularized than endochondral grafts. This factor may affect the greater volume maintenance seen in experimental membranous grafts.

Enxerto autógeno livre de cartilagem hialina com e sem a remoçäo do pericôndrio em processo malar de ratos: estudo histológico / Fresh autogenous rib cartilage graft to the malar process of rats without removal of the perichondrium: a histological study

Foi realizado um estudo comparativo entre o enxerto de cartilagem sem e com remoçäo do pericôndrio no processo malar de ratos. Foram empregados 72 ratos divididos em dois grupos de acordo com o tipo de enxerto recebido. Os períodos experimentais analisados foram de 5, 10, 20, 30, 60 e 120 dias após o ato cirúrgico. Os resultados obtidos mostram que no grupo controle que recebeu a cartilagem com o pericôndrio, o enxerto mantem a sua vitalidade e biologicamente integrado ao tecido cirúrgico. Nota-se crescimento aposicional da cartilagem. No grupo com cartilagem sem o pericôndrio, observa-se intensa reaborçäo do enxerto e intensa neoformaçäo óssea nas proximidades. Nos períodos longos nota-se o contato íntimo entre o enxerto e o tecido ósseo neoformado

Orbital tripod osteotomy for facial asymmetry.

An attempt has been made to provide an additional alternative to the treatment of zygomatic deformities. It is an approach that was used on a series of four patients but one that has met with success and satisfactory results in restoring more normal form and function. When performed correctly, the orbital tripod osteotomy is a physiologically and esthetically sound approach to the correction of the deformed or deficient cheek as a result of trauma or congenital malformation.