Page 73 - Craniomaxillofacial Implant Surgery - Jeroen P.J. Dings

Extra-oral implants – insertion per- or post-ablation?
DISCUSSION
This retrospective study focussed on the survival of endosseous implants in the orbital and nasal region in treated oncology patients in relation to the timing of placement.
The overall patient mortality following oncological orbital exenteration varies between
26% and 63% at 5 years25,26. Melanoma and adenocystic carcinoma are specifically
reported to have a poor long-term survival26,27. However, prognosis is dependent on a
large number of variables, such as surgical free margins, tumor location, origin, and
extent, and histological cell type. As squamous cell carcinoma is mostly seen in the
nasal cavity, the overall 5-year cumulative survival rate for different types of malignant
tumors of this cavity has been shown to be approximately 50%28. 4
As reported in the literature reviews, survival rates for orbital and nasal implants vary between 33% and 100%8,16,29,30. This wide variation can be explained by the differences in treatment techniques, duration of follow-up, patient factors, and criteria for implant success1,10-12,18,23,31. The current study shows an 5 years overall implant survival rate of 90.1% for extraoral implants placed during ablative surgery and 65.8% for extraoral implants placed after ablative surgery. In our opinion loss of extra-oral implants is not caused by epithesiologic loading but primarily by factors related to osseointegration. However, because of the heterogenous data collected from two different departments over a longer period (1997–2010), comparison has to be taken carefully. Moreover, statistical analysis in this study is based on individual implants considering the observations as independent samples instead of taking multiple measurements in individual patients.
Extra-oral implants can be placed during ablative surgery or during a second surgical session. Literature shows no consensus regarding the time of implant insertion17,32-35. Maxillofacial prosthetic reconstruction poses a challenging positioning of implants with respect to bone quality and volume often being limited. Pre-operative surgical planning and preparation could enhance the success rate and produce a more predictive treatment and cosmetic outcome when gross alterations in the anatomical situation occur36. Other advantages of implant placement during ablative surgery are: avoidance of implant surgery in a area compromised by radiotherapy; more space for manipulation while placing implants; avoidance of additional surgery; opportunities for earlier prosthetic rehabilitation and cost difference in preventing extra operating
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