Anoplasty for low anorectal malformation

    Anoplasty for Low Anorectal Malformation Christine Whyte, Timothy G. Canty, Janeen Smith, Kieran Melody PII: DOI: Reference:

S0022-3468(16)00210-4 doi: 10.1016/j.jpedsurg.2016.03.007 YJPSU 57640

To appear in:

Journal of Pediatric Surgery

Received date: Revised date: Accepted date:

12 January 2016 8 March 2016 18 March 2016

Please cite this article as: Whyte Christine, Canty Timothy G., Smith Janeen, Melody Kieran, Anoplasty for Low Anorectal Malformation, Journal of Pediatric Surgery (2016), doi: 10.1016/j.jpedsurg.2016.03.007

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ACCEPTED MANUSCRIPT Anoplasty for Low Anorectal Malformation

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Christine Whyte MD, Timothy G Canty MD, Janeen Smith PA-C, Kieran Melody MD Division of Pediatric Surgery, Albany Medical College, 47 New Scotland Avenue, Albany NY 12208

Corresponding Author: Christine Whyte MD Division of Pediatric Surgery Albany Medical College 47 New Scotland Avenue Mailcode 191 Albany, NY 12208. [email protected] Tel: 518 262 5831; Fax 518 262 4223

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Abstract Background: The presence of a slightly anterior, stenotic anus is a low anorectal malformation. It is a type of rectoperineal fistula. The cardinal symptoms are constipation and straining at stool. Hendren described a technically simple anoplasty for this condition in 1978. Controversy about terminology has led to a lack of clarity about this condition. Methods: Clinical data were reviewed about the authors’ patients, who had Hendren anoplasty, from 2009 to 2015. Followup data were obtained from office visits and telephone interviews with families and primary care doctors. Results: Seven patients (4 boys) presented with intractable constipation. All had a stenotic anal orifice, located anterior to the center of the anal wink, within the pigmented perianal skin. In 4 of 7 cases, the lesion was not recognized at birth. Anoplasty was performed at a median age of 8 months (range 6-28). Late followup information was obtained on six of the seven patients at a median of 32 months (range 28 – 61). Four reported no or minimal laxative requirement and two reported daily laxative use but good symptom control. Conclusions: Low anorectal malformation/rectoperineal fistula may be overlooked in the newborn. When symptomatic, it may be corrected by a simple anoplasty with excellent results. KEY WORDS: Anorectal malformation, constipation, anterior ectopic anus, rectoperineal fistula, anoplasty.

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ACCEPTED MANUSCRIPT 1.1. Introduction The clinical entity of constipation caused by anterior location of the anus was described by Bill in

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1958[1]. Hendren described a technically simple anoplasty for anterior anus in 1978[2]. There has been controversy about the definition and descriptive terminology of the condition [3,4,5]. Slight anterior

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displacement of the anus has been variously described as “anterior ectopic anus (AEA)”, “covered anus”, or “anteriorly displaced anus”. The most recent English language texts include this abnormality in the

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term “rectoperineal fistula” *6+.

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The term “rectoperineal fistula” is now used to describe a situation where the anus opens anteriorly to the normal location, passing anterior to, or partially through, the sphincter mechanism[6] (Fig. 1a,2a,4a).

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The anus in these lesions is usually stenotic. The most minor, proximal form may be corrected by a simple anoplasty, whereas a more displaced fistula is usually treated by a procedure to relocate the

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rectum within the sphincters [6] (Fig. 3).

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A source of confusion in this area is the entity of “anterior ectopic anus”*7,8+. Consensus has emerged that this term should only be used to describe a correctly formed anus and sphincter mechanism,

in this report.

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located more anteriorly than normal [4,5,6,7] . Its prevalence is disputed. It is not the lesion described

ABBREVIATIONS: VACTERL: Vertebral anomalies, Anorectal malformation, Cardiac anomalies, Tracheo Esophageal fistula, Renal anomalies, Limb anomalies; PSARP: posterior sagittal anorecto plasty; AEA: anterior ectopic anus; AGI: anogenital index; API: anal position index.

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ACCEPTED MANUSCRIPT 2.1. Materials and Methods The project was approved by the Albany Medical Center Institutional Review Board (Certificate Number

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4394). Records were obtained of the authors’ cases of Hendren anoplasty from 2009 to 2015. Clinical

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photographs were reviewed. All patients were under the care of a single clinician(CW). Followup data were obtained from office visits, telephone calls, or from primary care practitioners. A standardized

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questionnaire was administered to family members who were interviewed.

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2.2. Surgical Technique

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The technique has been described previously [2]. The patient is placed in lithotomy position. Antibiotics are administered. The center of the anal sphincter is defined visually and by muscle stimulation (Fig 4a).

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A circular skin flap is marked out, extending back from and including the posterior margin of the anus and encircling the area of the anal muscle contraction (Fig. 4b). Holding sutures are placed at each side

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of the flap and suspended over hemostat clamps placed on the drapes at each side, exerting moderate

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traction (Fig. 4b).

The skin is incised and the edge of the flap is grasped with hemostats. The skin flap is elevated. The

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sphincter fibers are pushed bluntly off the back of the flap with scissors, but they are not cut. This dissection is facilitated by placing a finger in the rectum and is carried just proximal to the dentate line, so that the upper part of the flap is full thickness of rectum (Figs 4b, 4c). The flap of skin is excised at the anocutaneous junction, by first cutting it vertically in the midline, placing the first stitch in the six o’clock position, and then removing the excess skin at each side (Fig.4c). The rectal wall is then sutured to the posterior skin edge with chromic catgut. The visible anal mucosa retracts inward afterwards. The procedure effectively opens out the stenotic orifice, straightens the path of the anus, and eliminates the posterior “shelf” by displacing the sphincter fibers posteriorly, without disrupting them. 4

ACCEPTED MANUSCRIPT Normal diet is resumed immediately. The patient is discharged home on laxatives. No dilatations are

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required. During follow-up, laxatives are weaned according to clinical response.

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ACCEPTED MANUSCRIPT 3.1. Results Over a six year period, in our community pediatric surgery practice, the authors have encountered seven

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cases of a distinct clinical problem characterized by the following features (Figs.1a, 2a, 4a): Anal stenosis

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Constipation

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Severe straining at stool

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Location of the stenotic anal orifice just anterior to the center of the anal contraction, within the

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anterior margin of the pigmented skin of the anal dimple, “Shelf” located posterior to the anal orifice

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There were four boys and three girls, operated at the ages of 6-28 months (median 8 months). All patients had a trial of laxative management prior to operation. Median age of onset of symptoms was 5

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months (range 0-7).

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Other anomalies were present in two of the seven cases, who exhibited features of the VACTERL

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association. One VACTERL patient had esophageal atresia and tracheoesophageal fistula, left diaphragmatic hernia (Bochdalek type), and vertebral anomalies. The other, born at 27 weeks, had duodenal stenosis and annular pancreas, atrial and ventricular septal defects. In three cases the lesion was recognized at birth and they were initially managed nonoperatively. Two of these three were the babies with VACTERL. In four patients, the anatomical abnormality was noted by the gastroenterologist or surgeon after referral for constipation. After operation, six of the seven patients were seen in surgical followup for one to three months. One, who lived far away,had telephone followup. The two patients with associated anomalies continue in

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ACCEPTED MANUSCRIPT long term followup. There were no complications. All families reported marked improvement in constipation and straining behavior immediately after surgery.

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Five patients were discharged on the day of surgery and two stayed one night. The first patient had daily anal dilatations at home for three weeks but no other patient had dilatations. No patient

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developed a stenosis after surgery.

Late followup information was obtained for six of the seven patients: in person (2), by telephone

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interview (3) or from the primary care physician (1) at median 32 months after operation (range 28-61).

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One patient was lost to late follow up, but at four months, was doing well.

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symptoms were well controlled.

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Four of the patients had no or only occasional constipation, two still needed daily laxatives but their

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ACCEPTED MANUSCRIPT 4.1. Discussion Proximal rectoperineal fistula is a low anorectal malformation and it is a distinct clinical entity. It may

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be overlooked at birth, as happened in four of our seven cases. It may be asymptomatic initially. Onset of symptoms typically coincides with the introduction of puree diet. It is a visual diagnosis.

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Hendren has provided a clear description of this condition [2]. He described it as “anterior location of the anus”. The photographs in Hendren’s original paper are identical to the patients in our report. He

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described a technically simple anoplasty to correct the problem. Its advantages are: No circumferential dissection of the anus

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Low risk of cicatrization of the new anal orifice

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No irreversible division of any sphincter muscle

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No need for postoperative dilatations

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Suitability for outpatient surgery

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Further reports of the condition and descriptions of variations of the technique of anoplasty have

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appeared [9,10,11,12]. We chose the technique described by Hendren because of its simplicity and clarity of description [2], and because one of our authors (TGC) trained in the technique with Dr Hendren.

Pena and Levitt have described low anorectal malformations in males and females, with the anus opening on the skin anterior to the anal dimple, the terminal portion of the rectum passing through the anterior part of the sphincter *6, 13, 14, 15+. These authors avoid the term “anterior ectopic anus” and refer to all such low malformations as “rectoperineal fistula” or “perineal fistula”. This terminology simplifies the diagnosis conceptually, but does not distinguish between different grades of the problem.

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ACCEPTED MANUSCRIPT Current standard English language pediatric surgery texts emphasize the techniques of minimal posterior sagittal anorectoplasty (PSARP) and minimal posterior sagittal anoplasty for these lesions

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[6,13,14,15]. The extent of surgical dissection is determined by the position of the fistula opening. The

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purpose of these elegant procedures is the meticulous relocation of the anus within the sphincters [6]. Descriptions of alternative techniques of anoplasty for minor lesions are omitted from modern pediatric

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surgery textbooks available to trainees in North America [6, 13,14,15].

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The concept of the minimal PSARP is attractive: it corrects the anatomical abnormality. This assumes that we fully understand the anatomy in these patients, and it requires perfect healing. The striated

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muscle of the external sphincter is divided under clear visualization, the aberrant anal orifice is relocated and the muscle is sutured together perfectly. Minimal PSARP requires a circumferential dissection and

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relocation of the anal opening in all cases, and dilatations are required in the postoperative period. For

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lesions where the anus is displaced by only a few millimeters, this is a significant dissection, and the burden of twice-daily anal dilatations is not trivial for a family. In contrast, the Hendren anoplasty

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retains the natural anocutaneous junction in the anterior anal circumference, and the neo-anus is

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unlikely to develop a circular scar. We prescribed a short course of postoperative anal dilatation for our first patient but quickly abandoned this practice because it is unnecessary. In addition, the procedure is of short duration and is suitable for outpatient surgery. In the anoplasty which we describe, the anterior portion of the anus remains anterior to the sphincter complex. However, in clinical practice, in our series of patients and in Hendren’s original group *2+, this appears not to affect the functional or cosmetic outcome (Fig. 2b). The lesion which we describe is a very low anomaly, affecting only the lowest few millimeters of the sphincter complex. The striated muscle is seen and pushed bluntly backwards off the flap during dissection, avoiding all muscle division. Also, by avoiding a circumferential dissection, the procedure preserves sensation and blood supply at

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ACCEPTED MANUSCRIPT the anterior anocutaneous junction. In our patients, the long term results of anoplasty were highly satisfactory in appearance and function (Fig.2b).

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The surgeon, dealing with such a patient, has to decide which procedure to offer. We have employed anoplasty where the rectoperineal fistula opening is minimally displaced and where it is possible to

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move the posterior wall back posterior to the center of the anal muscle contraction without any difficulty or distortion (Fig 2a). For patients with more anteriorly displaced fistulae, we perform PSARP

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(Fig.3). These distinctions are important if the surgeon is to avoid overly complex surgery on minor lesions. We recognize that this is a matter of judgment. In the operating room, the patient is examined

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carefully and the muscle stimulator is used. In cases suitable for anoplasty, the orifice is located just

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anterior to the center of the muscle contraction, within the pigmented skin of the anus. The term “anterior ectopic anus” (AEA) persists in the pediatric literature [8]. A proposed definition of

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such a hypothetical entity stipulates that there should be a normally formed anus, surrounded by

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normal sphincter muscle, located anterior to the normal location [4,5]. The Anal Position Index (API) was developed to describe anal position in babies [16]. API is calculated as

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a ratio of the fourchette-anal and ano-coccygeal distances in females and the scroto-anal and anococcygeal distances in males. AEA is defined by API less than two standard deviations below the mean. A large European study showed an incidence of AEA of 2% in a healthy newborn population [8]. The authors noted a high incidence of constipation in patients with AEA. Herek et al studied the incidence of AEA in a general pediatric population [7]. They concluded that AEA is a common harmless variant. However, they described a subset of patients, with a specific appearance, who all required surgery for constipation. Patients in this group had a visible anal dimple posterior to the anterior anus and a prominent posterior shelf, and the authors referred to this situation as a low anorectal anomaly.

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ACCEPTED MANUSCRIPT It now seems probable that AEA, as strictly defined by low API, in the absence of other anatomical abnormalities, is a relatively common variant, of limited clinical significance [7, 8]. Pena has

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commented that he did not see a single case of AEA in a series of over 1460 cases of anorectal

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malformation requiring surgical correction [4]. Many papers in the pediatric surgery literature were written on the subject of “anterior ectopic anus” but usage of this term has changed over time and it

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appears that many of the patients had what is now called a low anorectal malformation or rectoperineal

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fistula in standard texts [4,5,6,7, 13,14,15]. True “anterior ectopic anus”, as currently defined, is unlikely to be seen in a surgery clinic, whereas patients with minor or proximal rectoperineal fistula, as described

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in our report, may be referred for intractable constipation.

Proximal rectoperineal fistula may be diagnosed visually based on the frequent presence of anal

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stenosis, a prominent posterior shelf and the “eccentric” appearance of the anus in the periphery of the

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pigmented anal skin (Figs 1a,2a,4a). The relevance of the API to clinical decision making in these patients is not known, since it is the position of the anus relative to the sphincters that helps the

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surgeon to choose which procedure to perform and the API is not useful in isolation. It may be that

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calculation of the API in patients with low anorectal malformations is clinically useful, and the production of a relevant dataset could be a subject of future research. Awareness of this low anorectal malformation is important if it is not to be overlooked. Although it belongs in the spectrum of rectoperineal fistula, it is a relatively minor lesion and when symptomatic, may be successfully corrected by anoplasty [2]. The Hendren anoplasty is a technically simple and cost effective technique with prolonged good results in our experience with this condition.

5.1. Acknowledgement: The authors wish to acknowledge Dr Burton H Harris, for editing assistance.

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ACCEPTED MANUSCRIPT References 1. Bill AH Jr, Johnson RJ, Foster RA. Anteriorly placed rectal opening in the perineum ectopic anus; a

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report of 30 cases. Ann Surg. 1958;147:173-9.

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2. Hendren WH. Constipation caused by anterior location of the anus and its surgical correction. J Pediatr Surg 1978;13:505-12

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3. Schuster T, Joppich I, Schneider K, Jobst G. A computerised vector manometry study of the socalled

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ectopic anus. Pediatr Surg Int 2000;16:8-14

4. Pena A. Comments on anterior ectopic anus. Pediatr Surg Int 2004; 90:902

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5. Herek O. Anterior ectopic anus: an accurate definitive term for choice of treatment? Pediatr Surg Int 2001; 17:501.

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6. Levitt MA, Pena A. Anorectal Malformations. In: Operative Pediatric Surgery. Ziegler MM, Azizkhan RM, Von Allmen D, Weber TR, editors, 2nd ed. New York: McGraw-Hill Education; 2014.

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7. Herek O, Polat A. Incidence of anterior displacement of the anus and its relationship to constipation in

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children. Surg Today 2004;34:190-2.

8. Núñez-Ramos R, Fabbro MA, González-Velasco M, Núñez Núñez R, Romanato B, Vecchiato L, et al.

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Determination of the anal position in newborns and in children with chronic constipation: comparative study in two European healthcare centres. Pediatr Surg Int 2011;27:1111-5 9. Leape LL, Ramenofsky ML. Anterior ectopic anus: a common cause of constipation in children. J Pediatr Surg 1978;13:627-30. 10. Tuggle DW, Perkins TA, Tunell WP, Smith EI. Operative treatment of anterior ectopic anus: the efficacy and influence of age on results. J Pediatr Surg 1990;25:996-7; discussion 997-8. 11. Abeyaratne M. Posterior transposition of anterior ectopic anus. J Pediatr Surg 1991;26:725-7. 12. Shah AJ, Bhattacharjee N, Patel DN, Ganatra JR. Anal shift: preliminary results. J Pediatr Surg 2003;38:196-8.

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ACCEPTED MANUSCRIPT 13. Levitt MA, Bischoff A, Pena A. Anorectal Malformations. In: Operative Pediatric Surgery. Spitz L, Coran A, editors, 7th ed. Boca Raton: CRC Press;2013.

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14. Levitt MA, Pena A. Imperforate Anus and Cloacal Malformations. In: Ashcraft’s Pediatric Surgery.

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Holcomb GW, Murphy P, Ostlie D, editors, 6th ed. Philadelphia: Elsevier Saunders; 2014. 15. Levitt MA, Pena A. Anorectal Malformations. In: Pediatric Surgery. Coran AG, Adzick NS, Krumell TM,

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Laberge JM, Shamberger LC, Caldamone AA, editors, 7th ed. Philadelphia: Elsevier Saunders; 2012.

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16. Reisner SH, Sivan Y, Nitzan M, Merlob P. Determination of anterior displacement of the anus in

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newborn infants and children. Pediatrics 1984 73:216-7.

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ACCEPTED MANUSCRIPT Table/Figure Legends

Figure 1a. Newborn male with rectoperineal fistula: stenotic anus located anteriorly within the

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pigmented skin of the anal dimple. Posterior shelf present.

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Figure 1b. Same infant as 1a, after anoplasty procedure.

Figure 2a. Newborn female with rectoperineal fistula, anoplasty at 8 months of age.

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Figure 2b. Same patient as 2a , appearance at 3 years of age.

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Figure 3. PSARP: Patient with more anterior rectoperineal fistula, anus located outside muscle contraction. This orifice was considered to be too anterior for anoplasty. The patient underwent PSARP

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with temporary diverting colostomy. Compare with Fig 2a. Figure 4a. Rectoperineal fistula at 10 months.

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Figure 4b. Anoplasty as described by Hendren [2]. Flap outlined around center of muscle contraction. Holding sutures placed.

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Figure 4c. The flap has been elevated and divided in the midline. The initial suture has been placed in

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the 6 o’clock position. The excess skin on each side will be excised.

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Figure 4d. Edge of rectum sutured to skin. The exposed mucosa retracts inwards later.

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