圆锥角膜行光学板层角膜移植术后早期缝线松动的影响因素

目的 探讨圆锥角膜行光学板层角膜移植术（LKP）后早期缝线松动的影响因素.方法 回顾性系列病例研究.对2006年1月至2010年5月存山东省眼科医院接受LKP的圆锥角膜患者手术前后眼部特点进行研究,对其中在2009年11月之前手术的52例（56眼）患者的病所资料进行回顾性研究,了解患者角膜地形图、曲率、眼轴、角膜横径、供体植片保存方式,分析这些因素与术后早期缝线松动发生率及松线部位的关联性;对在2009年11月至2010年5月期间行角膜移植手术且发生松线的9例（9眼）圆锥角膜患者进行了角膜光学相干断层扫描（OCT）及激光共焦显微镜检查,以期了解术后早期缝线在角膜组织中的位置特点及缝线附近角膜组织形态.计量资料采用秩和检验.计数资料采用卡方检验进行统计学分析.结果 52例（56眼）圆锥角膜患者中,术后早期发生缝线松动37眼（占66%）,其中27眼在松线的基础上发生角膜植片翘起（占73%）,96%的植片翘起发生在术后3个月内.松线主要发生在下方角膜（占62%）,47%的松线发生在术前角膜最薄点及圆锥顶点所在象限.松线组与未松线组比较：术前角膜最薄点（x2=3.49,P＞0.05）及圆锥顶点（x2=1.62,P＞0.05）位置分布差异无 统计学意义;角膜最薄点厚度（u=0.21,P＞0.05）、角膜中央厚度（u=0.11,P＞0.05）差异无统计学意义;供体植片保存方式（x2=3.06,P＞0.05）、角膜最大曲率（u=0.66,P＞0.05）、眼轴（u=1.06,P＞0.05）、角膜横径（u=1.68,P＞0.05）差异也无统计学意义.随访检查的9眼中,缝线存角膜组织中的跨越深度与角膜厚度的比值,松线组小于末松线组（0.4258±0.0420 vs 0.4869±0.0609,u=2.32,P＜0.05）,发生松线的患眼多伴有角膜缘新生血管浸润,且缝线多由植床侧割裂角膜组织而发生松线,松线周围角膜组织可见到坏死组织、瘢痕及炎性细胞浸润.结论 圆锥角膜行LKP术后早期（3个月内）,缝线松动易并发角膜植片翘起,松线部位多见于下方角膜.原凶可能与缝线在角膜组织中的跨越深度不足、术后炎症反应、新生血管的形成及术前角膜病变程度有关.

Factors that lead to early postoperative suture loosening after optical lamellar keratoplasty for keratoconus

Objective To investigate the factors that lead to early postoperative suture loosening after optical lamellar keratoplasty (LKP) for keratoconus. Methods Retrospective case series study. Keratoconous patients who received LKP in Shandong Eye Hospital between January 2006 and May 2010 were reviewed. The case histories of 52 patients (56 eyes) who underwent surgery before November 2009 were reviewed retrospectively. Patients were divided into two groups: a suture-loosening group (37 eyes) and a non-suture-loosening group (19 eyes). Corneal topography, pachymetry, keratometry, axial length, corneal diameter and corneal preservative methods used were analyzed. Nine patients who underwent surgery during November 2009 to May 2010 were examined by slit lamp, anterior segment optical coherence tomography, and laser confocal microscopy, with the purpose of studying the local features of early postoperative sutures. Results Of the 56 eyes reviewed retrospectively, early postoperative suture loosening occurred in 37 eyes (66%), with graft fissure occurring in 27 of those eyes (73%), and 96% of these fissures occurred in the first three months after surgery. Suture loosening mainly occurred in the inferior cornea (62%), 47% of the graft fissures occurred in the same quadrant as the apex and the thinnest point of the lesion. When the suture-loosening group and the non-suture-loosening group were compared, there were no significant differences in the distribution in the apex (x2=1.62, P＞0.05) and the thinnest point (x2=3.49, P＞0.05), or corneal thickness in the central (u=0.11, P＞0.05) and thinnest points (u=0.21, P＞0.05).And there were no significant differences in maximum curvature (u=0.66, P＞0.05), axial length (u=1.06, P＞0.05), corneal diameter (u=1.68, P＞0.05), or corneal preservative methods used (x2=3.06,P＞0.05). Anterior segment optical coherence tomography showed that the ratio of the suture spanning depth in the corneal tissue and the thickness of the cornea was significantly different between the two groups (0.4258±0.0420 versus 0.4869±0.0609, u=2.32, P＜0.05). Slit lamp and confocal microscopy showed that many of the eyes in the suture-loosening group suffered from new vessel formation and the sutures were primarily loosening on the limbus side of the cornea. Necrotic tissue, cicatricle and inflammatory cells were also found in the suture-loosening area. Conclusion Suture loosening and graft fissures often occur during the early period after LKP for keratoconus, and the loosening tends to be located in the inferior cornea. Insufficient spanning depth of the suture in corneal tissue,inflammatory reaction, new vessel formation, and keratopathy may be causes of suture loosening.