Lee S J, Park Y S
Department of Surgery, Chungbuk National University Hospital, Korea.
Int J Colorectal Dis. 1998;13(5-6):241-6. doi: 10.1007/s003840050169.
This prospective study was performed to serially assess the changes in anorectal function after low anterior resection of the rectum, and to elucidate the mechanisms of functional impairment and the recovery process.
Thirty-two patients undergoing low anterior resection for rectal cancer were evaluated prospectively. Standardized interviews concerning anorectal function and physiologic studies consisting of manometry and balloon proctometry were performed preoperatively, then at 1, 3, and 6 months, and 1 year after the operation. Depending on the length of the residual rectum, patients were divided into two groups: (1) shorter than 4 cm (the short group, n = 18), and (2) longer than or equal to 4 cm (the long group, n = 14).
Postoperatively, stool frequency increased and urgency to defecate occurred, which continued until 3-6 months had passed and was more remarkable in the short group. Overall incontinence score increased, which was more remarkable in the short group. Anal resting pressure showed a moderate reduction after 3 months, whereas squeeze pressure did not decrease significantly. Rectoanal inhibitory reflex was postoperatively abolished in almost all patients in the short group, which showed nearly no recovery for 1 year. In the long group, it persisted postoperatively in half the cases, and the reflex returned in a few cases within 1 year. Balloon proctometry revealed overall reduction in rectal capacity and compliance. Although the values tended to recover steadily, they did not reach the preoperative level for 1 year. Urgent volume and maximal tolerable volume remarkably declined, which continued for 1 year and for 6 months, respectively. Rectal compliance also decreased considerably, which continued for 6 months. Most values of rectal capacity tended to be smaller in the short group.
Impairment of continence after low anterior resection seemed multifactorial, including diminished rectal capacity and compliance, impaired internal anal sphincter tone, and loss of rectoanal inhibitory reflex. Clinical outcome was better and reduction in rectal capacity was less in patients whose rectum remained more than 4 cm. Most of the functional impairments clinically recovered by 6 months postoperation. In the process of clinical recovery of continence, restoration of rectal capacity and compliance and internal anal sphincter tone seemed to contribute a significant degree, while the rectoanal inhibitory reflex did not contribute as much.
本前瞻性研究旨在连续评估直肠低位前切除术后肛门直肠功能的变化，阐明功能障碍的机制及恢复过程。
对32例行直肠癌低位前切除术的患者进行前瞻性评估。术前、术后1、3、6个月及1年进行关于肛门直肠功能的标准化访谈以及包括测压和气囊直肠测压在内的生理研究。根据残留直肠的长度，患者被分为两组：（1）短于4cm（短组，n = 18），（2）长于或等于4cm（长组，n = 14）。
术后，排便次数增加且出现便急，这种情况持续至术后3 - 6个月，短组更为明显。总体失禁评分增加，短组更为显著。肛门静息压在术后3个月出现中度下降，而挤压压无明显降低。短组几乎所有患者术后直肠肛门抑制反射消失，1年内几乎无恢复。长组中，术后半数患者该反射持续存在，少数患者在1年内反射恢复。气囊直肠测压显示直肠容量和顺应性总体降低。尽管这些值有稳步恢复的趋势，但1年内未达到术前水平。紧急容量和最大耐受容量显著下降，分别持续1年和6个月。直肠顺应性也明显降低，持续6个月。短组的直肠容量多数值往往较小。
直肠低位前切除术后控便功能障碍似乎是多因素的，包括直肠容量和顺应性降低、肛门内括约肌张力受损以及直肠肛门抑制反射丧失。直肠残留长度超过4cm的患者临床结局较好，直肠容量减少较少。大多数功能障碍在术后6个月临床恢复。在控便功能的临床恢复过程中，直肠容量和顺应性以及肛门内括约肌张力的恢复似乎起了很大作用，而直肠肛门抑制反射的作用较小。
