開發及驗證脛骨平台水平矯形術的客製化手術導板:體外試驗

Abstract

前十字韌帶的損傷是犬隻最常見的膝關節骨科疾病之一，臨床治療最常使用的切骨校正手術為脛骨平台水平矯形術(Tibial plateau leveling osteotomy, TPLO)，由於解剖構造的差異，小型犬隻的手術困難度較高，必須由經驗豐富的外科醫師進行手術。近年來，三維列印的技術在獸醫領域開始應用在肩關節固定手術、遠端股骨骨切開校正手術、畸形矯正等等骨科手術，結果發現三維列印的手術導板可以提升手術效率、增加手術的精確度。然而目前並無在中小型犬隻以三維列印客製化手術導板進行TPLO的相關研究，本研究即針對TPLO的手術導板進行研究，建立應用於中小型犬隻的脛骨平台水平矯形術客製化三維列印手術導板，以達到精確的手術結果。 材料方法：本研究使用10 - 15公斤的中小型犬隻大體，使用熔融沉積成型列印，材料為ABS。研究分為兩階段，第一個階段為確認本實驗之三維列印系統所製作之脛骨可提供可靠的再現性及精確度、並且本系統製作之脛骨外觀不受到電漿滅菌的影響，以二維方式比較其長度、寬度、脛骨平台角度以及以三維方式比較其表面的精確度、不同橫切面之周長。第二階段為利用三維列印系統製作脛骨模型，並且以客製化三維列印手術導板於模型上進行脛骨平台水平矯形術。本部分會比較二維脛骨平台角度、切割圓心位移、以及三維的表面差異來確認達成預期的手術結果。 結果：第一部分實驗，二維脛骨平台角度在列印骨與大體骨間、滅菌前與滅菌後間皆無顯著差異。二維脛骨長度與寬度在滅菌前後之差異為-0.66-0.55%。三維外觀差異均方根在列印骨與大體骨間為0.11 ± 0.02 釐米、滅菌前與滅菌後間為0.04 ± 0.02 釐米，兩組有顯著差異。脛骨之5%、15%、25%、50%、75%、85%、95%處之三維橫切面差異均方根在列印骨與大體骨、滅菌前與滅菌後兩組間於所有區段下兩組別皆有顯著差異。第二部分實驗，脛骨平台角度之誤差在控制組(5.3 ± 3.3o)顯著大於手術導板組(0.4 ± 0.6o)，而大體組(1.2 ± 2.4o)與手術導板組則沒有顯著差異。在二維切線圓心位移的結果，控制組之誤差距離(3.07 ± 1.18 釐米)顯著大於手術導板組(0.93 ± 0.77釐米) (p < 0.0001)。手術導板組與大體組(0.89 ± 0.78 釐米)間則沒有顯著差異(p = 0.9)。三維外觀測量均方根差異在控制組(0.72 ± 0.17釐米)與手術導板組(0.33 ± 0.12釐米)有顯著差異(p < 0.0001)。 結論：以本實驗之製程所得到的三維列印模型具有足夠的精確度，且電漿滅菌並不會造成外觀的影響。而本實驗所建立之三維列印客製化手術導板可提供中小型犬進行脛骨平台水平矯形術時達到足夠精確的校正結果，後續仍須進一步的臨床應用研究。

Cranial cruciate ligament injury is one of the most common orthopedic diseases noted in canine. Dogs may recover with great clinical outcomes after tibial plateau leveling osteotomy (TPLO) surgery. However, due to the large difference of tibial morphology on small-median breed dogs, TPLO need to be performed by experienced surgeons. Recently, the three-dimensional (3D) printing technology has been widely used in the veterinary medicine field. Using a patient-specific instrument (PSI) during surgery may decrease surgical time and has good clinical results in shoulder arthrodesis, distal femoral corrective osteotomies, and bone deformity correction. To our best knowledge, there is no study about the patient-specific surgical guide for TPLO in small-medium breed dogs. This research aimed to develop and validate the efficacy of PSI for TPLO. Materials and methods: Twelve pelvic limbs collected from six mixed-breed canine cadavers (body weight: 10 - 15 kg) were used. Computed tomographic images of the tibia models and designed PSI were printed with the FDM desktop 3D printer using ABS. First, the shape accuracy of the tibia models and the effects of H2O2 plasma sterilization were evaluated by three parameters: Tibia length and cross-sectional width, tibial plateau angle (TPA), and the root mean square (RMS) difference on tibia surface. Second, the clinical accuracy of TPLO performed by PSI on the tibia models were evaluated by TPA, distance of eccentricity (DOE), and the RMS difference of the TPLO performed tibia models. Results: The comparison of the tibia length and width between 3D group and sterilized group, the relative results were from -0.66% to 0.55% and absolute differences were always under a millimetre. ICC showed strong/perfect agreement. The TPA showed no significant difference between cadaver group, 3D group, and sterilized group. The surface difference RMS between the CT-3D model group (0.11 ± 0.02mm) was significantly higher than 3D-sterilized group (0.04 ± 0.02 mm). The comparison of the cross-sectional profile deviation of the tibia model, the mean RMS values of CT-3D group at 5% of the total bone length were significantly higher than those at the other six cross-sections. The differences in mean RMS values of 3D-sterilized group at all seven cross-sections were nonsignificant. The deviation at the proximal tibia (5%) with high curvature increased noticeably during 3D printing. Moreover, no regional deviation was observed in the tibia model after H2O2 plasma sterilization. Second, the mean deviation of the postoperative TPA from the intended 5° in the control group (5.3 ± 3.3°) was significantly greater than in the PSI group (0.4 ± 0.6o). There were no significant differences between the PSI group and cadaver group (1.2 ± 2.4o). Mean DOE was significantly higher in the control group (3.07 ± 1.18 mm) than in the PSI group (0.93 ± 0.77 mm). There were no significant differences between PSI group and cadaver group (0.89 ± 0.78 mm). The surface RMS was significantly higher in the control group comparison (0.72 ± 0.17 mm) than in the PSI group comparison (0.33 ± 0.12 mm). Conclusion: Our tibia model may provide clinically acceptable accuracy before and after H2O2 sterilization. The patient-specific surgical guide for TPLO can provide more precise surgical results in small-medium breed dogs than the traditional free hand TPLO surgery. However, further clinical application study should be needed.