Orbit Rehabilitation with Extraoral Implants: Impact of Radiotherapy

Implant prognosis in irradiated versus non-irradiated nasal, orbital and auricular sites

The purpose of this systematic review was to evaluate implant survival in irradiated nasal, auricular, orbital sites and to compare them with non-irradiated respective sites. Four electronic databases and seven related journals were searched until December and March 2018, respectively. A total of 7892 articles were identified, 18 of which were included in this review; one non-randomized clinical trial, two prospective cohort, eight retrospective cohort and seven cross-sectional studies. Using the ROBIN-I Cochrane tool for risk assessment, 13 studies were judged at serious, one at moderate and four at critical risk of bias. Thirteen were included in 18 meta-analyses, the results of which showed a significant difference between irradiated and non-irradiated sites, favouring non-irradiated with risk ratio (RR) = 0.93, 95% confidence interval (CI) 0.89-0.97, P=0.001. Comparisons among nasal, auricular and orbital sites revealed no significant differences, whether in irradiated or non-irradiated patients at P<0.05. Hence, it was concluded that, within the limitations of this review, survival of craniofacial implants is negatively affected by radiotherapy, especially in orbital sites. Level of evidence is moderate. Therefore, further prospective cohort studies with calculated sample sizes, restricted or properly managed confounders and no deviations from intended interventions might produce different results.

Frontal sinus augmentation: Preliminary results of a new approach in prosthetic orbital reconstruction

PURPOSE

Reliable application of endosseous implants for prosthetic facial reconstruction depends on the bone volume available at the defect site. Regarding the orbit, sufficient bone presentation in the medial superior orbital rim is limited due to the frontal sinus. The aim of this article is to report for the first time on the augmentation of the frontal sinus for gaining bone volume for supraorbital implant placement.

MATERIALS AND METHODS

Between 2007 and 2014, five patients with orbital exenteration were treated by frontal sinus augmentation using autogenous cancellous bone graft from the ilium. Extraoral implants for prosthetic orbit reconstruction were placed 4-7 months later. In advance, cadaver surgery was performed to prove the feasibility of the method. Surgical technique is described, and intraoperative images are provided.

RESULTS

The frontal sinus was successfully augmented in all five patients. No major complications related to the procedure were observed. A total of nine orbital implants were inserted in the augmented bone, thereof one sleeping implant. Six implants were restored prosthetically, two implants were lost at exposure. The observation period ranged from 6 to 97 months (mean: 52.8 months). Mean time for patient rehabilitation was 13 months. High patient satisfaction was achieved with the implant-retained orbital prosthesis.

CONCLUSION

The augmentation of the frontal sinus allows implant placement by providing sufficient bone volume in the medial supraorbital rim. Considering the surgical success of this method and patient satisfaction, this new approach is concluded to be a viable option in a unique subset of patients.

Quality of life assessment of patients utilizing orbital implant-supported prostheses

STATEMENT OF PROBLEM

Evaluate the effect of orbital prosthesis retained by implants through a specific quality of life (QOL) questionnaire provides important information on patients QOL, great incentive for the multidisciplinary team and public health support to continue work in this area.

PURPOSE

The objective of the study was to evaluate patient satisfaction with orbital implant-supported prostheses using an adapted quality of life questionnaire.

MATERIALS AND METHODS

Forty five patients using orbital implant-supported prostheses for a period ranging from six to 120 months. The subjects answered a questionnaire that consisted of 10 questions covering appearance, retention, conspicuousness, self-confidence, difficulty of placement, difficulty of removal, cleaning, limitation of activities, discomfort of tissues, and recommendation of the method to other patients. Answers were expressed using a visual 100-mm scale. The arithmetic mean of the responses was converted into a percentage to represent the satisfaction index.

RESULTS

Patients demonstrated a high level of satisfaction on all items, with the lowest rate being for aesthetics and the highest being for recommending the method to other patients. High satisfaction rates regarding the placement and removal of the prosthesis, discomfort to the tissues, and cleaning suggest the ease of handling of the prosthesis. High satisfaction with retention, self-confidence, conspicuousness of the prosthesis, and limitation of activities indicated an association with a better social life.

CONCLUSIONS

The results showed that use of bone anchorage technique of extraoral prostheses provided a high level of satisfaction among patients, confirming that osseointegrated implants are a very important resource for the rehabilitation of orbital deformities.

Osseointegration and implant stability of extraoral implants in Göttingen minipigs after irradiation

OBJECTIVES

The aim of this study was to compare the influence of implant surface treatment and irradiation dose on implant stability and osseointegration of 144 extraoral implants in irradiated frontal bone of minipigs.

MATERIAL AND METHODS

144 implants with 3 different surface treatments (machined, etched and HAVD-coated) were implanted in the frontal bone of 16 Göttingen minipigs. Three groups of four pigs received radiation with equivalent doses of 25, 50 and 70 Gy, and one group served as control. Resonance frequency analysis (RFA) was performed recording Implant Stability Quotients (ISQ) at implant placement and 3 months thereafter. Removal torque was measured whilst removing specific implants after 3 months. In addition, the bone-to-implant contact (BIC) was analyzed.

RESULTS

Evaluation of ISQ, BIC-values showed no significant difference between the different surface treatments in irradiated and non-irradiated bone. Removal torque revealed statistically significant differences between machined and HAVD-coated implants in the irradiated bone.

CONCLUSIONS

Implant stability and osseointegration, based on Removal Torque showed significant higher results for the HAVD-coated implants. No significant difference was observed between the irradiated and non-irradiated animals. This study shows that HAVD-coated extraoral implants can potentially be used for craniofacial rehabilitation in non-irradiated and irradiated bone.