Guided placement of zygomatic implants in head and neck cancer patients: implant survival and patient outcomes at 1-3 years of follow-up

Zygomatic implants (ZI) are a valuable option for supporting an obturator prosthesis after maxillary resection. This study was performed to assess the clinical outcomes of a digitally validated guided technique for ZI placement, followed by immediate prosthetic obturation. The primary objective was to evaluate implant survival, while the secondary objective was to assess patient-reported quality of life post-rehabilitation. Twelve patients treated for head and neck cancer received a total of 36 ZI after ablative surgery. The mean duration of ZI follow-up was 30.1 months. The survival rate of ZI placed in non-irradiated patients was 100%, while it was 85% in irradiated patients. Patient-reported outcomes were evaluated using the Liverpool Oral Rehabilitation Questionnaire (LORQv3) and the University of Washington Quality of Life Questionnaire (UW-QOL v4). Most patients reported satisfactory outcomes in the oral function domain of the LORQv3 (mean score 17.7 ± 4.5; possible range 12-48, with lower scores indicating better outcomes). Regarding the UW-QOL v4, the swallowing and chewing domains had the highest scores (mean 97.5 ± 8.7 and 95.8 ± 14.4, respectively; maximum possible score of 100). In conclusion, this treatment approach improves function and quality of life after maxillary ablative surgery. However, irradiated patients showed a noticeable trend of higher implant failure, and this was influenced by tumour position and size impacting the radiation dose to the zygomatic bone.

Immediate implant-retained prosthetic obturation after maxillectomy based on zygomatic implant placement by 3D-guided surgery: a cadaver study

Background

The aim of this study was to introduce a complete 3D workflow for immediate implant retained prosthetic rehabilitation following maxillectomy in cancer surgery. The workflow consists of a 3D virtual surgical planning for tumor resection, zygomatic implant placement, and for an implant-retained prosthetic-obturator to fit the planned outcome situation for immediate loading.

Materials and methods

In this study, 3D virtual surgical planning and resection of the maxilla, followed by guided placement of 10 zygomatic implants, using custom cutting and drill/placement-guides, was performed on 5 fresh frozen human cadavers. A preoperatively digitally designed and printed obturator prosthesis was placed and connected to the zygomatic implants. The accuracy of the implant positioning was obtained using 3D deviation analysis by merging the pre- and post-operative CT scan datasets.

Results

The preoperatively designed and manufactured obturator prostheses matched accurately the per-operative implant positions. All five obturators could be placed and fixated for immediate loading. The mean prosthetic point deviation on the cadavers was 1.03 ± 0.85 mm; the mean entry point deviation was 1.20 ± 0.62 mm; and the 3D angle deviation was 2.97 ± 1.44°.

Conclusions

It is possible to 3D plan and accurately execute the ablative surgery, placement of zygomatic implants, and immediate placement of an implant-retained obturator prosthesis with 3D virtual surgical planning.The next step is to apply the workflow in the operating room in patients planned for maxillectomy.

mTHPC mediated photodynamic therapy (PDT) of squamous cell carcinoma in the head and neck: a systematic review

OBJECTIVE

Photodynamic therapy (PDT) is used in curative and palliative treatment of head and neck squamous cell carcinoma (HNSCC). To evaluate available evidence on the use of mTHPC (Foscan®) mediated PDT, we conducted a review of the literature.

MATERIALS AND METHODS

A systematic review was performed by searching seven bibliographic databases on database specific mesh terms and free text words in the categories; "head and neck neoplasms", "Photodynamic Therapy" and "Foscan". Papers identified were assessed on several criteria by two independent reviewers.

RESULTS

The search identified 566 unique papers. Twelve studies were included for our review. Six studies reported PDT with curative intent and six studies reported PDT with palliative intent, of which three studies used interstitial PDT. The studies did not compare PDT to other treatments and none exceeded level 3 using the Oxford levels of evidence. Pooling of data (n=301) was possible for four of the six studies with curative intent. T1 tumors showed higher complete response rates compared to T2 (86% vs 63%). PDT with palliative intent was predominantly used in patients unsuitable for further conventional treatment. After PDT, substantial tumor response and increase in quality of life was observed. Complications of PDT were mostly related to non-compliance to light restriction guidelines.

CONCLUSION

The studies on mTHPC mediated PDT for HNSCC are not sufficient for adequate assessment of the efficacy for curative intent. To assess efficacy of PDT with curative intent, high quality comparative, randomized studies are needed. Palliative treatment with PDT seems to increase the quality of life in otherwise untreatable patients.