Department of Ophthalmology, Mainz University Medical Center, Mainz, Germany.
J Glaucoma. 2011 Apr-May;20(4):246-51. doi: 10.1097/IJG.0b013e3181e080ef.
OBJECTIVE/AIM: Uncontrolled glaucoma presents a challenge for the ophthalmic surgeon especially in children and juvenile patients. For many patients who have undergone failed surgical procedures before, episcleral implants remain the last choice. Encapsulated blebs forming over antiglaucoma devices present a complication leading to malfunctioning or even failure with reincrease in intraocular pressure. We report our histopathologic findings of such blebs developing around the Ahmed glaucoma valve (AGV) after a short time period in young patients.
Nine young patients (2 to 17 y of age) with otherwise uncontrollable glaucoma were treated with AGV (models FP-7 and FP-8, silicone base plate) by 1 surgeon (H.T.). Four eyes needed surgical revision 2 to 6 months after initial implantation owing to encapsulated bleb development over the valve with total loss of function. The dense capsule around the device was surgically removed and investigated macroscopically, microscopically, and ultrastructurally.
The cystic wall of these encapsulated blebs had an overall thickness of 1.5 to 2 mm. Macroscopically, the tissue was split into 2 layers. Histopathologically, the smooth inner surface (facing the base plate of the AGV) consisted of compressed collagen fibers with signs of elastoid degeneration and with formation of a pseudoendothelium toward the base plate. There was a pronounced transformation of fibroblasts into myofibroblasts in this inner layer. The outer area was highly vascularized. In these vessels electron microscopy revealed thrombosis. Inflammatory responses were nearly absent in all areas of the excised material. Intraocular pressure could be controlled by removal of the encapsulated blebs in all 4 cases.
Encapsulation of the AGV is an early complication in young patients, leading to inhibition of fluid exchange and failure of the procedure. The valve mechanism is blocked by contracted scar tissue, but the device itself is not affected by the encapsulation. Surgical excision of the capsule immediately leads to an aqueous flow and drop of intraocular pressure.
青光眼失控对眼科医生来说是一个挑战，尤其是在儿童和青少年患者中。对于许多之前手术失败的患者，巩膜植入物仍然是最后的选择。抗青光眼装置上形成的包裹性囊泡是一种并发症，可导致装置功能障碍甚至失效，眼压再次升高。我们报告了在年轻患者中， Ahmed 青光眼阀 (AGV) 短时间内出现此类囊泡的组织病理学发现。
由 1 位外科医生 (H.T.) 对 9 名年龄在 2 至 17 岁、患有其他不可控青光眼的年轻患者采用 AGV（型号 FP-7 和 FP-8，硅胶底板）进行治疗。由于阀门上包裹性囊泡形成，导致阀门完全丧失功能，其中 4 只眼在初次植入后 2 至 6 个月需要手术修复。手术切除致密的囊泡周围组织，进行大体、显微镜和超微结构检查。
这些包裹性囊泡的囊壁总厚度为 1.5 至 2 毫米。大体上，组织分为 2 层。组织病理学上，面向 AGV 底板的平滑内层由压缩胶原纤维组成，有弹性变性的迹象，并向底板形成假内皮。内层中有明显的成纤维细胞向肌成纤维细胞转化。外层富含血管。在这些血管中，电子显微镜显示血栓形成。所有切除标本的炎症反应均几乎不存在。在所有 4 例中，通过切除包裹性囊泡均可控制眼内压。
在年轻患者中，AGV 包裹是早期并发症，导致液体交换抑制和手术失败。阀门机制被收缩的瘢痕组织阻断，但装置本身不受包裹的影响。囊泡切除术后立即出现房水流动和眼内压下降。
