ITI Zygoma

李俊瑩醫師

此篇是 ITI Consensus Workshop，第一次針對 Zygoma implant 編寫共識會議指引。

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▋ 前言

Zygoma implant主要適用於上顎骨萎縮或不足的病例。平均追蹤時間為75.4個月（6.3年）的情況下，長期平均Zygoma implant的存活率為96.2％，追蹤時間為36–141.6個月（3–11.8年）。

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相較於delay loading，Immediate loading統計上存活率顯著增加。在平均65.4個月的追蹤，Sinusitis的發生率為14.2％，這是導致Zygoma implant失敗最常見併發症。

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此篇 ITI Consensus Workshop共識會議提出了有關規劃、手術、假牙重建、結果和以患者觀點出發的共識指引以及臨床建議。

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底下節錄重點專家共識指引。

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▋ 一. 適應症 (Indications)

李醫師總結，Zygoma implant 適用於：

1.上顎骨萎縮或不足的病例

2.曾經補骨或植體失敗的病例

3.患者希望避免多次手術補骨的患者

4.接受過良性囊腫和外傷…等複雜性切除上顎骨手術患者

5.先天性上顎骨缺損，外傷及顎骨切除的替代性治療

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▋ 二. 存活率 (Survival)

1. The mean survival rate between 90.3% and 100% after a follow-up of 6 months.

2. The mean survival rate of 97% (89–100%) in a mean follow-up period of 28.5 months (range 12–162 months).

3. The mean zygomatic implant survival 96.2% [95% CI 93.8; 97.7] over a mean follow-up of 75.4 months (6.3 years) with a follow-up range of 36–141.6 months (3–11.8 years).

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➤ 李醫師總結

2 篇 system review 和 1 篇 meta-analysis 顯示，Zygoma implant 中長期追蹤有 90% 以上成功率。

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▋ 三. Quad. zygoma

Quad. zygoma 需上顎左右各兩隻 Zygoma implant 且必須 splinting，適用於一般植體前後牙區無法置放，補骨預期不佳的患者。

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▋ 四. Loading protocol (立即受力或延遲受力)

Immediate Loading protocols: were 98.1% [95% CI 96.2; 99.0] over a mean of 73.6 months follow-up.

Delayed load protocols:was 95% [95% CI 91.7; 97.1] over a mean of 69.3 months follow-up.

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➤ 李醫師總結

Zygoma implant 立即受力成功率略高，但需要注意oro-antral communications 風險，李醫師建議當發生較大口鼻穿通時建議採用 delayed load protocols.

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▋ 五. Surgical risks (手術風險)

共識來自一篇systematic review:

• Transient infraorbital nerve (V2) – 15例

• Oro-antral communications- 15例

• Peri-abutment soft tissue recession and/or hyperplasia 16 report Fractured ZI was described. 6例

• ZI malposition, orbital cavity penetration – 4例

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➤ 李醫師總結

拉勾請溫柔一點不要傷及V2神經，備孔請不要過大造成oro-antral communications，置入方向避免侵犯眼框，植體平台與alveolar bone support關係會影響植體受力與後續軟組織可能的併發症。

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▋ 六. Failures (植體失敗)

This statement is based on a meta-analysis of 17 case series reports, which included a total of 1247 ZIsA higher failure incidence may occur within the first year (2%) compared to that of subsequent years (0.5%/year).

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➤ 李醫師總結

第一年失敗率較後續幾年高，第一年失敗原因為植體本身未骨整合或不夠穩定。後續失敗原因為生物性併發症或機械性因素導致植體失敗。

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▋ 七. Sinusitis (鼻竇炎)

Sinusitis is the most commonly reported biological complication related to ZI therapy. Sinusitis is reported to be the most common complication which may lead to ZI implant loss.

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➤ 李醫師總結

鼻竇炎為最常見導致 Zygoma implant 失敗的併發症，發生率從2.8% ~ 36.4% 不等。

鼻竇炎與手術技巧相關， Original surgical technique (OST) were 9.5% (0–37.5%), Anatomy- Guided were 4.4% (0–11.8%).

鼻竇炎經抗生素或合併surgical meatotomy皆可成功治療。

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▋ 八. Biological complications (生物性併發症)

1. Peri-implant ZI mucositis at 13.1% (3.7–41%) within an atrophic group and 39.7% (9.7–91.7%) in an oncologic group

2. Recession exposing 2–3 threads : 14%

3. Soft tissue dehiscences : 9%

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➤ 李醫師總結

口腔衛生不佳，Zygoma implant不穩定，crestal bone太薄或缺乏，與置放位置太頰側都會導致後續發生生物性併發症。

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▋ 九.Technical complications (機械性併發症)

1.The mean prosthesis survival supported by ZIs was 94% [95% CI 88.6; 96.9] at 76.0 months of mean follow-up.

2.Technical complications for ZI supported reconstructions include fracture of the metal substructure, chipping or loss of the veneering material (ceramic or acrylic), and abutment or screw fracture and/or loosening.

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➤ 李醫師總結

Zygoma implant支持的假牙中長期追蹤有94%成功率。有alveolar bone support的zygoma implant穩定性較佳，受力較小

▋ Clinical recommendations 臨床建議節錄

• Zygomatic implant是一項複雜的術式，成功與否取決與臨床醫師的專業技術和經驗。

• 診斷工具需要包括中顏面的CT/CBCT 3D影像評估，用來評估上顎骨，顴骨骨量，及上顎鼻竇腔健康與否。

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Ｑ：上顎骨萎縮到什麼程度才適合施行Zygoma implants?

Ａ：The most cited anatomical classification is Cawood and Howell (1988), with class IV, V and VI.

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Ｑ：Zygoma implant可以在拔牙處同時拔除立即植牙嗎？

Ａ：在拔牙窩施行zygoma implant的併發症風險會增加。