Historical Background
Postanal repair was developed by Sir Allan Parks in the 1970s [1] and popularised in the early 1980s for patients with neuromyopathic faecal incontinence.
The original objective of this operation was to restore the anorectal angle, which was thought to be an important factor in continence. In 1975, Parks sug- gested the flap–valve theory that stressed the impor- tance of the acute anorectal angle. According to this theory, a rise in intra–abdominal pressure caused the upper end of the anal canal to be occluded by anteri- or rectal mucosa, preventing rectal contents from entering the anal canal. Neuromyopathic faecal incontinence was associated with perineal descent and an obtuse anorectal angle, which rendered the flap-valve-like mechanism ineffective. Further inves- tigations, however, failed to show changes of the anorectal angle, and currently, it is thought that an improvement of muscular contractility is responsible for any improvement in continence [2].
Postanal repair involves coaptation of the levator ani, puborectalis and external anal sphincter posteri- or to the anal canal and the anorectal junction by approximating these muscles with nonabsorbable sutures. The anatomical result of this procedure is lengthening of the anal canal and possible reduction of the anorectal angle.
Anatomic Consideration
The anal canal is 3–5 cm long, passing from the dis- tal rectum to the anal verge. The puborectalis muscle passes posterior to the anorectal junction, forming a sling that draws the anorectal junction forwards (Fig. 1). The length of the anal canal and the sling action of the puborectalis are thought to be impor- tant parts of the continence mechanism. Patients with neuromyopathic incontinence have a shorter anal canal and a straightening of the anorectal angle.
The anorectal angle is the angle between the longitu- dinal axis of the rectum and the anal canal. It can be
assessed either by defecating proctography or mag- netic resonance imaging (MRI). Normal values range from 90° to 110° at rest, increasing to about 135° dur- ing defecation. In patients with idiopathic inconti- nence, the angle at rest is straightened to greater than 110°.
Indications
Postanal repair is currently performed on patients with idiopathic faecal incontinence with no evidence of sphincter defect on endoanal ultrasound. It should only be offered when conservative treatment with dietary manipulation, drug therapy and physiothera- py has been implemented without success. The patients expected to benefit most from postanal repair are women with a history of multiple vaginal deliveries [2–4].
Postanal Pelvic Floor Repair
Saleh M. Abbas, Ian P. Bissett
17
Fig. 1. Sagittal view of the pelvis on magnetic resonance imaging (MRI). Note the dotted line indicating the inter- sphincteric plane dissected in postanal repair. AC anal canal, LA levator ani, EAS external anal sphincter, PR pub- orectalis, IAS internal anal sphincter, PB pubic bone. (Pic- ture by Professor Stuart Heap, University of Auckland, Department of Anatomy and Radiology)
rather than a postanal repair. Rectal prolapse should be excluded by careful history and examination and if necessary, a defecating proctogram.
Defecating proctography is a dynamic fluoroscop- ic examination performed by instilling thick barium contrast into the rectum and capturing lateral images during defecation. It is useful in assessing both anatomy and function of the anal canal and pelvic floor during defecation. PNTML is the measurement of the time from stimulation of the pudendal nerve at the ischial spine to the response of the external anal sphincter. Normal PNTML is <2.2 ms, and is often prolonged in patients with neuropathic faecal incon- tinence. Electromyography recruitment records the change from basal electrical activity of motor units of the external anal sphincter and levator muscles dur- ing muscle activity. This may a useful adjunct in the investigation of neuropathic incontinence.
teric plane, which is relatively bloodless. Fibres of the external sphincter are red in colour and contract with diathermy stimulation, while those of the internal sphincter are white and do not contract to diathermy current. Dissection is then deepened in the inter- sphincteric plane to the upper part of the external sphincter and puborectalis muscle, finally exposing the levator ani fascia and the mesorectal fat. This dis- section is extended anteriorly to include half of the circumference of the anal canal. A deep 90° angled retractor is used to push the rectum anteriorly in order to see the highest and the most lateral part of levator ani (Fig. 3).
The levator ani is then approximated using 2/0 nonabsorbable sutures (Prolene or Ethibond). Using a small curved needle to include a large bundle of muscle fibres, three sutures are inserted at this uppermost level. The sutures are then tied loosely to
Fig. 2. Incision is curvilinear posterior to the anal canal.
Reprinted with permission from Elsevier [5]
Fig. 3.Dissection in the intersphincteric plane to reveal puborec- talis and levator ani. Reprinted with permission from Elsevier [5]
create a lattice across the pelvis (Fig. 4). The pubo- coccygeus muscle is approached next and additional 2/0 nonabsorbable sutures are placed in a similar fashion by approximation of the lower fibres (Fig. 5).
Sutures in the puborectalis are the most important in the repair, as this muscle is the strongest of the pelvic floor. The sutures are placed as anteriorly as possible, lifting the anorectal junction forwards. The sutures are then tied loosely approximating the two
arms of the puborectalis. Usually, three sutures are utilised to approximate the muscles of the external sphincter. The approximation should not be tight (Fig. 6). The skin is then closed using absorbable sutures.
Postoperative Care
A urinary catheter is generally used to avoid reten- tion and removed the following morning. Pain relief is given according to the patient’s needs. Bowel sof- teners are used in the immediate postoperative peri- od to avoid faecal impaction and achieve semiliquid stools; patients are instructed to avoid straining, as this may disrupt the repair. The patient is usually dis- charged home 24–48 h after the operation and remains on laxatives for several weeks. Long-term use of laxatives may be required.
Discussion
Parks first described postanal repair in 1975 [1], and reported very good continence results in 80% of patients. The procedure is usually performed on patients with neuropathic faecal incontinence who have an intact anal sphincter with poor sphincter contractility. Typically, the patients are older women with multiple vaginal deliveries and a weak pelvic floor.
Since its description by Parks, postanal repair has been applied in various parts of the world and re-
Fig. 4.Sutures in the upper levator ani are loosely tied tocreate a lattice behind the rectum. Reprinted with permis- sion from Elsevier [5]
Fig. 5.Approximation of pubococcygeus by nonabsorbable sutures. Reprinted with permission from Elsevier [5]
Fig. 6.Approximation of external sphincter and puborectal- is. Reprinted with permission from Elsevier [5]
ported to accomplish modest success [9, 11]. Studies have shown improvement of 35 and 88% in faecal incontinence following postanal repair [2, 6–12]
(Table 1), with only small numbers of patients achieving full continence. Factors that have been sug- gested to affect the outcome of postanal repair include preoperative physiological parameters such as resting anal tone, maximum squeeze pressure, PNTML, concentric needle electromyography, unde- tected external sphincter defects and pelvic floor descent and anorectal angle, as seen preoperatively on defecating proctography. None of these factors, however, has predicted long-term outcome, with the possible exception of maximal squeeze pressure before surgery [9–11, 13–15]. The exact mechanism of the effect of postanal repair is not fully under- stood, although changes in the length of the anal canal, rectal angle, change in resting anal pressure, maximum squeeze pressure and pelvic floor descent or anorectal angle following postanal repair have been proposed as possible mechanisms. These have not been proved on long-term follow-up to correlate with the outcome [2]. A randomised controlled trial by Deen et al. [14] in women with neuropathic faecal incontinence compared total pelvic floor repair with anterior levatorplasty and sphincter plication alone and postanal repair alone. Review at 6 and 24 months indicated that results were significantly better for total pelvic floor repair than either of the other pro- cedures.
The majority of patients with faecal incontinence are found to have weak but intact external anal sphincters. This is attributed to a variety of reasons, such as diabetes and pudendal neuropathy [16]. Risk factors for idiopathic incontinence are female gen- der, advancing age, ill health and physical disability [17]. A recent systematic review showed a prevalence of faecal incontinence between 11% and 15% [17-19], but the proportion of those who have neuropathic incontinence is not known. A number of other treat- ment options are available for this type of faecal
incontinence. These include conservative measures aimed at achieving symptomatic control (such as dietary manipulation, pharmacotherapy including constipating agents, and phosphate enemas) and pelvic floor retraining, also called biofeedback [20].
Newer modalities, such as sacral nerve neuromodu- lation, have shown promise.
Conclusion
The patients most likely to benefit from postanal repair are women with a history of multiple vaginal deliveries and a weak but intact external anal sphinc- ter on endoanal ultrasound. Although the initial results of this procedure were promising, more recent results have been variable. The current place of postanal repair in the management of faecal incon- tinence patients is unclear, as there are few data com- paring it with other available procedures. It is of ben- efit to patients with mild to moderate idiopathic fae- cal incontinence and can be offered in conjunction with other treatment modalities.
References
1. Parks AG (1975) Anorectal incontinence. P Roy Soc Med 68:681–690
2. Athanasiadis S, Sanchez M, Kuprian A (1995) Long- term follow-up of Parks posterior repair. An elec- tromyographic, manometric and radiologic study of 31 patients. Langenbeck Arch Chir 380:22–30 3. Vaizey CJ, Kamm MA, Nicholls RJ (1998) Recent
advances in the surgical treatment of faecal inconti- nence. Br J Surg 85:596–603
4. Browning GG, Parks AG (1983) Postanal repair for neuropathic faecal incontinence: correlation of clini- cal result and anal canal pressures. Br J Surg 70:101–104
5. Fielding LP, Goldberg SM (1993) Rob & Smith’s oper- ative surgery. Surgery of the colon, rectum and anus, 5th edn. Butterworth-Heinemann, London
6. Womack NR, Morrison JF, Williams NS (1988) Prospective study of the effects of postanal repair in neurogenic faecal incontinence. Br J Surg 75(1):48-52 7. Yoshioka K, Keighley MR (1989) Critical assessment of
the quality of continence after postanal repair for fae- cal incontinence. Br J Surg 76:1054–1057
8. Engel AF, van Baal SJ, Brummelkamp WH (1994) Late results of postanal repair for idiopathic faecal inconti- nence. Eur J Surg 160:637–640
9. Jameson JS, Speakman CT, Darzi A et al (1994) Audit of postanal repair in the treatment of fecal inconti- nence. Dis Colon Rectum 37:369–372
10. Rieger NA, Sarre RG, Saccone GT et al (1997) Postanal repair for faecal incontinence: long-term follow-up.
Aust NZ J Surg 67:566–570
11. Matsuoka H, Mavrantonis C, Wexner SD et al (2000) Postanal repair for fecal incontinence-is it worthwhile?
Dis Colon Rectum 43:1561–1567
12. Abbas SM, Bissett IP, Neill ME, Parry BR (2005) Long- term outcome of postanal repair in the treatment of faecal incontinence. ANZ J Surg 75(9):783-786 13. Setti CP, Kamm MA, Nicholls RJ (1994) Long-term
results of postanal repair for neurogenic faecal incon-
tinence. Br J Surg 81:140–144
14. Deen KI, Oya M, Ortiz J, Keighley MR (1993) Random- ized trial comparing three forms of pelvic floor repair for neuropathic faecal incontinence. Br J Surg 80:794–798
15. Kamm MA (1998) Fortnightly review: faecal inconti- nence. BMJ 316:528–532
16. Scott AD, Henry MM, Phillips RK (1990) Clinical assessment and anorectal manometry before postanal repair: failure to predict outcome. Br J Surg 77:628–629
17. Nelson R, Norton N, Cautley E, Furner S (1995) Com- munity-based prevalence of anal incontinence. JAMA 274:559–561
18. Johanson JF, Lafferty J (1996) Epidemiology of fecal incontinence: the silent affliction. Am J Gastroenterol 91:33–36
19. Macmillan AK, Merrie AE, Marshall RJ, Parry BR (2004) The prevalence of fecal incontinence in com- munity-dwelling adults: a systematic review of the lit- erature. Dis Colon Rectum 47:1341–1349
20. Liavag I, Aanestad O (1985) Fecal incontinence. Diag- nosis treatment. Ann Gastroent Hepato 21:247–250
