Strackee S D, Kroon F H, Jaspers J E, Bos K E
Department of Plastic, Reconstructive, and Hand Surgery at the Academic Medical Center, Amsterdam, The Netherlands.
Plast Reconstr Surg. 2001 Dec;108(7):1915-21; discussion 1922-3. doi: 10.1097/00006534-200112000-00010.
The fibula osteocutaneous free flap has become the preferred method for most cases of mandibular reconstruction after oncologic surgical ablation. To recreate the parabolic form of the mandible, the fibula has to be divided up into segments using a closed wedge osteotomy technique. The number of osteotomies is preferably kept to a minimum so that segmental periosteal circulation is not compromised and also to keep operating time to a minimum. The limited number of osteotomies creates an angular contour. The aim of this study was to establish the degree to which overcorrection or undercorrection would occur when a subtotal reconstruction from ramus to ramus was simulated using five bony segments and four osteotomies. The study was carried out using 30 preserved jaws; the contour lines of the jaws were transferred onto tracing paper using a cardboard template. The contour of the mandible was divided into five sections (ramus, body, symphysis, body, and ramus). Because of the cutting off of the curvature in the original jaw outline, the lateral side of the body will become narrower and the chin broader. This also results in an underprojection (displacement) of the chin. To follow the original contour of the jaw as accurately as possible, all these anomalies must be minimized. The amount of under- and overprojection is calculated for a displacement of 1.0, 1.5, 2.5, 5.0, 7.5, and 10 mm of the chin. The most accurate reconstruction of the mandibular contour is achieved with a displacement of 1.5 or 2.5 mm. To preserve sufficient periosteal circulation, the minimum width of bone segments must be 15 mm or more. This concerns especially the symphysis section. On the basis of a fibula thickness of 14 mm, the internal bone width of the symphysis section is calculated. With a displacement of 1.5 mm, the average internal width of the bone segment is 14.8 mm, with a range of 9.9 to 23.0 mm (95 percent confidence interval, 12.8 to 16.7 mm). Therefore, a displacement of 2.5 mm with an internal bone width of 16.4 mm is preferred (range, 11.9 to 24.8 mm; 95 percent confidence interval, 15.5 to 18.2 mm). The loss of lateral projection is minimal (5.8 mm) and the resulting chin width is acceptable (average, 35.0 mm). In conclusion, we propose that in a subtotal procedure, an acceptable jaw reconstruction can be achieved with a limited number of osteotomies. The bone length of the symphysis section remains within safe limits. If the defect is of limited dimensions, then the resulting jaw contour is even more accurate.
腓骨骨皮瓣已成为肿瘤手术切除后大多数下颌骨重建病例的首选方法。为了重建下颌骨的抛物线形态，必须使用闭合楔形截骨技术将腓骨分成若干节段。截骨的数量最好保持在最少，这样节段性骨膜循环就不会受到影响，同时手术时间也能保持最短。有限的截骨数量会形成一个有角度的轮廓。本研究的目的是确定当使用五个骨段和四次截骨模拟从下颌支到下颌支的次全重建时，过度矫正或矫正不足的程度。该研究使用了30个保存的颌骨；颌骨的轮廓线通过硬纸板模板转移到描图纸上。下颌骨的轮廓被分为五个部分（下颌支、体部、颏部、体部和下颌支）。由于原始颌骨轮廓中的曲率被截断，体部的外侧会变窄，下巴会变宽。这也会导致下巴的下突（移位）。为了尽可能精确地遵循颌骨的原始轮廓，所有这些异常都必须最小化。计算下巴移位1.0、1.5、2.5、5.0、7.5和10毫米时的下突和上突量。下颌骨轮廓最精确的重建是在移位1.5或2.5毫米时实现的。为了保留足够的骨膜循环，骨段的最小宽度必须为15毫米或更大。这尤其涉及颏部。根据腓骨厚度为14毫米，计算颏部的内部骨宽度。移位1.5毫米时，骨段的平均内部宽度为14.8毫米，范围为9.9至23.0毫米（95%置信区间，12.8至16.7毫米）。因此，首选移位2.5毫米，内部骨宽度为16.4毫米（范围，11.9至24.8毫米；95%置信区间，15.5至18.2毫米）。外侧突度的损失最小（5.8毫米），由此产生的下巴宽度是可以接受的（平均，35.0毫米）。总之，我们建议在次全手术中，通过有限数量的截骨可以实现可接受的颌骨重建。颏部的骨长度保持在安全范围内。如果缺损尺寸有限，那么由此产生的颌骨轮廓会更精确。
