Tintara H, Aiyarak P, Mitarnun W, Geater A
Department of Obstetrics and Gynecology, Faculty of Medicine, Prince of Songkla University, Hat Yai, Songkhla, 90110, Thailand.
Surg Endosc. 2005 Feb;19(2):240-4. doi: 10.1007/s00464-004-9018-3. Epub 2004 Oct 26.
The physical properties of three commercial 5-mm myoma-fixation devices available for clinical use (short-pitch corkscrew, long-pitch corkscrew, buttress-thread screw) and a standard wood screw were examined.
Fresh specimens of uterine leiomyoma masses were used to test the maximum traction force obtained from each device on 31 occasions. The myoma tissue at each traction site was evaluated histologically to determine its density. The maximal traction forces in each myoma density group were compared using a generalized estimating equations approach to linear regression based on repeated measures within each myoma. The bending strength also was determined for each device.
A wide range of maximum traction forces with a mean of 130.8 +/- 71.5 N (range, 21.6-341.6 N) over all devices and tissue densities was recorded. The mean maximum traction force provided by the short-pitch corkscrew (159.2 +/- 12.2 N) was significantly higher (p < 0.01) than that of the other devices in medium-density myomas, and not significantly lower than that of other devices in low-density myomas. The mean maximum traction force provided by the buttress-thread screw was significantly lower than that of the short-pitch corkscrew only in medium density myomas, and did not differ significantly from that of the wood screw in any density group. The wood screw provided the highest bending strength (6.73 x 10(4) N/m) (whereas the short- and long-pitch corkscrew provided the lowest (9.70 x 10(2) N/m and 1.95 x 10(3) N/m, respectively) and the buttress-thread screw an intermediate (2.24 x 10(4) N/m) strength (p < 0.0005 for all comparisons except for the two corkscrews).
Screw-type myoma-fixation devices can provide comparable traction force with high bending strength. A long-pitch corkscrew should not be used for laparoscopic myomectomy because of its low traction force and bending strength. When a commercial screw is not available, a standard wood screw can be used with acceptable traction force and very high strength for bending.
对三种可供临床使用的5毫米肌瘤固定装置（短节距螺旋、长节距螺旋、支撑螺纹螺钉）以及一种标准木螺钉的物理特性进行了研究。
使用新鲜的子宫平滑肌瘤标本，31次测试每种装置获得的最大牵引力。对每个牵引部位的肌瘤组织进行组织学评估以确定其密度。使用基于每个肌瘤内重复测量的广义估计方程方法进行线性回归，比较每个肌瘤密度组中的最大牵引力。还测定了每种装置的抗弯强度。
记录了所有装置和组织密度下广泛的最大牵引力范围，平均值为130.8±71.5牛（范围为21.6 - 341.6牛）。短节距螺旋提供的平均最大牵引力（159.2±12.2牛）在中密度肌瘤中显著高于其他装置（p < 0.01），在低密度肌瘤中不显著低于其他装置。支撑螺纹螺钉提供的平均最大牵引力仅在中密度肌瘤中显著低于短节距螺旋，在任何密度组中与木螺钉相比无显著差异。木螺钉具有最高的抗弯强度（6.73×10⁴牛/米）（而短节距和长节距螺旋提供的抗弯强度最低，分别为9.70×10²牛/米和1.95×10³牛/米），支撑螺纹螺钉的抗弯强度居中（2.24×10⁴牛/米）（除两种螺旋之间的比较外，所有比较的p < 0.0005）。
螺旋式肌瘤固定装置可提供相当的牵引力和高抗弯强度。长节距螺旋由于其低牵引力和抗弯强度，不应在腹腔镜子宫肌瘤切除术中使用。当没有商用螺钉时，标准木螺钉可用于提供可接受的牵引力和非常高的抗弯强度。
