ANORECTAL MALFORMATIONS AND THE PROGNOSTIC VALUE

OF SACRAL RATIOS AT LASUTH

A Dissertation Submitted To the National Postgraduate Medical

College of Nigeria

BY

Dr Ogechukwu Chibuzo IDIKA

M.B.B.S (U. Nig)

DEPARTMENT OF LAGOS STATE UNIVERSITY

TEACHING HOSPITAL IKEJA, LAGOS

IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR

THE AWARD OF THE FELLOWSHIP OF THE MEDICAL

COLLEGE IN SURGERY (FMCS)

MAY 2012

DECLARATION

1

I hereby declare that the work in this dissertation is original and where the work of others has been used, this has been fully acknowledged in the text. The work has not and will not be submitted, in part or full for any other examination or to any other body for publication.

…………………………………………….

Idika Ogechukwu .C; M.B, B.S; (U. Nig)

2 ATTESTATION

This is to certify that this dissertation undertaken by Dr Idika Ogechukwu Chibuzo, titled

“Anorectal Malformations and The Prognostic Value Of Sacral Ratios at LASUTH” was carried out under our supervision.

……………………………… ………………………………

PROF. M. A. BANKOLE, FMCS, DR R.I OSUOJI

, MBBCH,

CONSULTANT PAEDIATRIC SURGEON FMCS, FWACS, FICS

CONSULTANT PAEDIATRIC SURGEON

3 DEDICATION

This work is dedicated to Oluwafemi David Tobechukwu Taiwo, the birth of whom has given me a fresh appreciation of the gift of life and the need to invest it in adding value to others.

4 ACKNOWLEDGEMENT

I acknowledge my Father God, who has given me life and the necessary grace and motivation to conquer whatever challenges come my way.

I appreciate Prof Michael A Bankole, my Head of unit, trainer and Supervisor, whose passion for this specialty comes through in all he does, for his commitment and invaluable guidance during this work and throughout my residency training. I also acknowledge Dr

Roland I. Osuoji, for his availability and constant encouragement. The entire Paediatrc

Surgery unit of LASUTH, I also appreciate for their understanding and assistance during this project.

I will not fail to thank Dr Balogun of the department for his input in this work. I also appreciate my colleagues and friends for being there with necessary support and encouragement.

Finally, Agboola Olanrewaju Taiwo, your love and assistance have contributed immensely not only to the conclusion of this project but throughout my residency programme. May our

Almighty God continually increase you on all sides.

5

TABLE OF CONTENTS

PAGES

TITLE PAGE ………………………………………………………………………. i

DECLARATION …………………………………………………………………… ii

ATTESTATION ……………………………………………………………………. iii

DEDICATION……………………………………………………………………….. iv

ACKNOWLEDGEMENT………………………………………………………….. v

TABLE OF CONTENTS……………………………………………………………. vi

LIST OF ABBREVIATIONS………………………………………………………..

viii

SUMMARY…………………………………………………………………………... ix

CHAPTER ONE …………………………………………………………………….. 1

Introduction…………………………………………………………………….. 1

1.1 Scope of the study…………………………………………………………….. 2

1.2 Justification for the study……………………………………..……………….. 3

CHAPTER TWO

Literature review……………………………………………………………. 4

6

CHAPTER THREE

Objectives ……………………………………………………………………….. 21

CHAPTER FOUR

Methodology ………… ……………………………………………………… 22

CHAPTER FIVE

Results ……………………………………………………………………….. 28

CHAPTER SIX

Discussion ………………………………………………………………… 45

CHAPTER SEVEN

Conclusion and Recommendations ……………………………………… 49

References …………………………………………….…………………………. 51

Appendices ………………………………………………………………… 56

7

LIST OF ABBREVIATIONS

AP Pullthrough Abdominoperineal pull-through

AP Anteroposterior

ARM Anorectal Malformation

CT Computerised Tomography

Gli2 Glioma associated oncogene homolog 2

Gli3 Glioma associated oncogene homolog 3

L/S Lumbosacral

LASUTH Lagos State University Teaching Hospital

LAT Lateral

MRI Magnetic Resonance Imaging

O.P Ref Outpatient Referral

PSARP Posterior Sagittal Anorectoplasty

RVF .Rectovestibular .

Shh Sonic Hedgehog signaling pathway

SR Sacral Ratios

USS Ultrasound Scan

VACTERL Vertebral Anorectal Cardiac Tracheooesophageal Renal and

Limb

VUR Vesicoureteric Reflux

8

SUMMARY

Objective: To determine the prevalence of associated vertebral anomalies in patients with

Anorectal Malformations in LASUTH and assess the prognostic value of Sacral ratios.

Methodology: A prospective study of 44 old and new patients who presented with

Anorectal Malformations to the Paediatric Surgery unit in Lagos State University Teaching

Hospital over a 15month duration. They were thoroughly examined with particular attention paid to the perineum and subsequently had plain lumbosacral radiographs done. Their biodata, type of anomaly and the presence of associated anomalies were noted. Various surgical treatment modalities were offered depending on the type of anomaly and mode of presentation. Complications and outcome within the study period were also recorded. Their

Sacral ratios were calculated from the lumbosacral radiographs, interpreted as normal or abnormal based on Pena’s criteria and correlated to the outcome.

Results: Of the 44 patients seen, 21(47.7%) were male and 23(52.3%) female. 17(38.6%) had intermediate anomalies, 14(31.8%) low and 13(29.5%) high anomalies. Vertebral anomalies were found to be the most predominant associated anomalies, occurring in 10 patients (22.7%). Other associations found were Renal/urogenital in 7 patients (15.9%),

Cardiac in 4 patients (9.1%) and Limb anomalies in one patient (2.3%). The mean Antero- posterior Sacral Ratio (APSR) + SD was 0.70 + 0.78 while the mean Lateral Sacral Ratio

(LSR) + SD was 0.76 + 0.71.

A large proportion (Twenty-nine, 80.6%) of the patients assessed for continence had a good outcome, while seven patients (19.4%) had soiling of their underwear.

Conclusion: Sacral ratios do not have a significant effect on conclusively predicting outcome of management in patients with Anorectal Malformations.

9

CHAPTER ONE

INTRODUCTION

Anorectal Malformations are a spectrum of clinical presentations of an abnormal termination of the anorectum. It has an average incidence of 1 in 5000 live births1, 2, 3. There is a slight male preponderance1, 2, 4, 5. This group of malformations can be initially diagnosed with a

“good pair of eyes” i.e. a proper/thorough perineal examination.

These anomalies come with a number of challenges posed to the patient, parents and caregivers. The problems range from intestinal obstruction in the neonatal period and beyond, recurrent urinary tract infections and social difficulties such as stigmatization. To the managing team, challenges arise in form of a need for early diagnosis and intervention to relieve intestinal obstruction, proper classification of the anomalies as well as appropriate timing for definitive treatment of the varied presentations.

They are traditionally classified as low, intermediate and high anomalies depending on the level of termination of the relative to the striated muscle complex. The defect can be further characterized by the presence of an accompanying fistula to the urogenital system or the perineum. About 5% of patients have been identified as having a malformation without a fistula6 .Co-existing anomalies of other systems, which have been well documented as the

VACTERL association, are factors associated with increased morbidity and mortality1,

7.Various imaging modalities have been used for the determination of the level of the rectal pouch, hence enabling their classification. Among these are: the Lateral Invertogram, Prone

10 cross table lateral radiograph and the Distal loopogram2, 8, 9. Others are Pelvic Magnetic

Resonance Imaging (MRI), Pelvic Computerized Tomographic Scanning (CT scan) and

Transperineal Ultrasonography 2,6,9. Plain radiographs of the lumbosacral spine may be done to assess the presence of associated vertebral anomalies such as hemivertebrae or sacral anomalies. A sacral ratio can also be derived and be used as a valuable prognostic tool for the prediction of continence, as it quantifies the degree of sacral hypodevelopment.1, 2, 10

Thorough documentation of these problems provides an evidence based approach to their management. Research has been done in various aspects ranging from the aetiology, epidemiology, investigations to treatment modalities.

Associated vertebral anomalies particularly of the sacrum have been noted to correlate with sphincteric dysfunction including post-surgical faecal incontinence. For this reason, it is important to document the incidence of associated vertebral anomalies and determine their statistical significance, viz-a- viz the occurence of faecal incontinence. This enables the to prognosticate appropriately.

1.1 SCOPE OF THE STUDY

This is a prospective study to document the prevalence of vertebral anomalies in patients with Anorectal Malformations as seen at Lagos State University Teaching Hospital

(LASUTH), Ikeja as well as determine their Sacral Ratios.

11

1.2 JUSTIFICATION FOR THE STUDY

1. The study will provide documentary evidence of the actual prevalence of associated

vertebral anomalies within the study population and assess their statistical

significance.

2. By predicting the likelihood of continence in these patients, based on the presence of

sacral anomalies as well as calculated Sacral Ratios, patient care can be further

individualized.

3. It has the potential to generate further multicentre studies on this subject.

12 CHAPTER TWO

LITERATURE REVIEW

2.1 EMBRYOLOGY

Anorectal development relates to the caudal end of the embryo. The events involving this part of the embryo occur between the end of the 3rd week and the 8th week of gestation.

Gastrulation, which refers to the rearrangement process that forms the three germ layers and sets the stage for tissue formation and organogenesis, begins to occur during this period. It is recognised that the genes responsible for the patterning of the caudal region are not clearly identified or elaborated unlike those of the cranial region; however there is an intimate relationship between muscles, bones and nerves in this region2, 11.

The Cloaca in the embryo is a cavity into which opens the hindgut, allantois and later the mesonephric ducts11, 12. It is formed at about the third week of gestation and is U shaped with the allantois lying anteriorly and the hindgut posteriorly. The urorectal septum in the middle grows downward and fuses with the lateral folds (Rathke’s plicae) until it joins the cloacal membrane, thereby dividing the Cloaca into an anterior urogenital cavity or sinus and a posterior rectal cavity. This development occurs over a period of 6 weeks. The cloacal membrane is displaced posteriorly as the shape of the Cloaca changes with rapid growth of the genital tubercles. The cloacal membrane breaks down at 7 weeks gestation thereby creating 2 openings the urogenital and anal openings. Absence of any of the dorsal part of the Cloaca and its membrane seem to give rise to a spectrum of fistulae or communication of the hindgut with the urogenital tract 11.

13 Events leading to the formation of Anorectal Malformations (ARM) have been ascribed to a much earlier time in gestation (i.e. gastrulation); their formation is not solely the result of the growth of the urorectal septum2, 11.

Traditionally these malformations were said to occur due to an arrest of the caudal growth of the urorectal septum towards the cloacal membrane during the 4th to 8th week of gestation.

The growth, migration and differentiation of this mesoderm constitute a critical pathway for normal growth of the urorectal septum as well as the tissues of mesodermal origin in this vicinity1, 2

It has been said that embryonic induction of specific developmental pathway in one group of cells i.e. growth of the urorectal septum may induce adjacent tissues (i.e. sacral somites) to transform into muscles, bones and skin4. Proteins of the extracellular matrix (e.g. laminin, fibronectin and collagen types I and IV) as well as growth factors might alter the induction of organs or disrupt cell-cell interaction after specification by a genetic code. Furthermore activation of a sequential group of genes or intracellular biochemical changes may also play a role in affecting the induction of these tissues. Such is the case for the expression of sonic hedgehog (Shh gene) and its secreted protein signalling pathway.11, 12

Transcription factors responsive to Shh such as Gli2 and Gli3 may also be equally important in the genesis of anorectal malformations and normal caudal region embryology. In the absence of Shh signalling or Gli2, the most posterior end of the hindgut fails to differentiate into anorectum whereas epithelial differentiation of urogenital tract remain intact.

Hence a spectrum of anorectal anomalies results from dysmorphogenesis of the urorectal septum which is of mesodermal origin. Others, possibly result from genetic affectation of the induction of muscle, bone and nerves of the caudal region in weeks 3 to 8 of gestation2,

11.

14 Evidence from animal models and human fetuses with major anomalies suggest that the earliest morphological defect leading to anorectal malformations is a deficiency in the dorsal component of the cloacal membrane and the adjacent dorsal Cloaca. It has also been reported by Qi BQ et al13 that the notochord controls the development of the spinal cord, vertebral column and anorectum and appears pivotal in the development of Anorectal malformations which, as a result, are commonly associated with underlying vertebral and spinal cord anomalies13.

2.2 ASSOCIATED ANOMALIES.

The implication of dysmorphogenesis this early in gestation is that patterning of the embryo is altered, therefore if something abnormal occurs early in gestation we should look regionally for other anomalies.11

This is of clinical relevance because there is a 40-50% overall incidence of associated anomalies occurring in association with anorectal malformation4, 11, 14, 15. Higher anomalies are associated with more malformations. The more complex the anorectal malformation, the more likely the presence of spinal and vertebral anomalies1, 2, 11.

Several reports recognizing associated anomalies in other midline structures including the vertebrae were recorded as well as genetic abnormalities associated with ARM such as trisomy 13, 18 and 21(Down’s syndrome). The Currarinos triad, which refers to the presence of a presacral mass, an “” and sacral agenesis, was described first by

Ashcraft and Holder2. The VACTERL association describes the range of possible associated malformations involving Vertebral, Anorectal, Cardiovascular, Tracheoesophageal,

Renal/Genitourinary systems as well as the Limbs.

15 Spinal and vertebral anomalies are identified in 1/3-1/2 of patients with ARM1 ,8, 16,17, the most common vertebral anomalies are in the Lumbosacral region and include hemivertebrae, scoliosis, butterfly vertebrae and hemisacrum1,8.

Sacral hypodevelopment is quantified by the sacral ratio measured in the Anteroposterior and lateral views of the pelvis in a plain radiograph of the Lumbosacral spine. It is a ratio obtained by measuring the distance from the lowest point of the sacrum to the lowest point of the sacroiliac joint and dividing it by the distance from the iliac crest to the lowest point of the sacroiliac joint. It was proposed by Alberto Pena in 1995 as a reliable tool to evaluate sacral development in Anorectal malformations. When the ratio is 0.74 and above, the likelihood of post-operative continence increases2, 10, 18.

Other than structural/ anatomical abnormalities evident in children with ARM, they have been found to have:

1. Varying degrees of development of the striated muscle complex from almost normal

appearance to virtually no muscle at all1, 2.

2. Inability to discriminate anorectal contents like normal individuals since a majority

of them are born without an anal canal.1, 2

3. A spectrum of rectosigmoid motility disorders. All these affecting their bowel

control1,2 .

2.3 CLASSIFICATION OF ANORECTAL MALFORMATIONS

Various classification systems have been used to describe this group of anomalies and including:

16 a) Gross’ classification6 in which Anorectal malformations were divided into 2 groups

depending on the level of the rectal pouch relative to the Levator ani muscle, hence

Supralevator and Infralevator b) International classification of 19706 in which the Low, Intermediate, High and

miscellaneous lesions both in males and female were recognized3. c) Wingspread classification of 19841, 2, 6, 19 was elaborated at Wingspread, Wisconsin.

This distinguished between high, intermediate & low anomalies in the male and

female, with special groups established for Cloacal and rare malformations. This

classification gained popularity for its detailed descriptive nature and is still

commonly in use (Table A). d) Pena classification of 19956: It was observed by Pena, that 2/3 of patients with ARM

had Posterior Sagittal Anorectoplasty done and considered that the sex of the patient

did not seem to be important in the choice of surgical approach. He proposed a

classification which was based on the relationship of the terminal rectum to the

striated muscle complex of the pelvic floor and distinguished between the various

fistulae that may be present. It is descriptive and takes into particular consideration

the fistula related grouping. The exclusion of the sex of the patients in this

classification is however a deficiency, as certain anomalies are known to occur only

in a particular gender e.g. Cloacal malformations in females and covered anus in

males. e) Krickenbeck classification of 20052, 6, 19 (Table B) which took into consideration rare

types of anomalies not previously recognised and the Pouch colon reported from the

Indian subcontinent. The Pouch colon is defined as an anomaly in which the whole

or part of the colon is replaced by a pouch-like dilatation, which communicates

17 distally with the urogenital tract by a large fistula.20The aim of this classification,

was for thorough discussion on international classification of anorectal

malformations.

i) To form international criteria for their treatment.

ii) To develop a uniform international scoring system for comparable follow-up.

By and large anorectal malformations are classified according to the sex of the patient and the specific anatomy of the malformation identified as outlined below.

18 CLASSIFICATION OF ANORECTAL MALFORMATIONS

Table A

Wingspread Classification

MALE FEMALE

High Anorectal Agenesis with High Anorectal Agenesis with

Rectovesical fistula Rectovaginal fistula

Rectoprostatic urethral fistula Without fistula

without fistula Rectal Atresia

Rectal atresia

Intermediate Intermediate

Rectobulbar urethral fistula Rectovestibular

Anal agenesis without fistula Rectovaginal

Anal agenesis without fistula

Low Low

Anocutaneous fistula Anovestibular

Anal stenosis Anocutaneous

Covered anus Anal Stenosis

Cloacal Malformation

19 Table B

KRICKENBECK CLASSIFICATION 2005

Major Clinical groups Perineal (Cutaneous) Fistula

Rectovesical fistula

Rectourethral fistula

Bulbar

Prostatic

Vestibular Fistula

Cloaca

No Fistula

Anal Stenosis

Rare/Regional Variants Pouch Colon

Rectal Atresia/Stenosis

Rectovaginal fistula

H –type fistula

Others

This classification takes it for granted that there is a pre-existing knowledge of the group of anomalies being classified.

20 2.4 DIAGNOSTIC MODALITIES

The diagnosis of Anorectal malformations (ARM) has evolved over the years. However as earlier stated a thorough perineal examination in good light is still of utmost importance in its immediate recognition, as a first step in the diagnosis of this group of anomalies.

Radiological investigations along with other imaging techniques play an immense role in further evaluation of these patients.

1. The Lateral Invertogram was described in 1930 by Wangensteen and Rice as a

diagnostic modality. This involved holding the neonate in an inverted position, with

the use of splints to achieve a true lateral position and a radiopaque marker is placed

on the perineal dimple. This position is maintained for three minutes in order to

achieve a downward displacement of meconium in the inverted rectal pouch, and a

plain lateral radiograph centered on the greater trochanter is taken. This investigation

should be done 18-24 hours after birth2,6. The radiographs are interpreted by

comparing the level of gas in the terminal rectum to various landmarks, the

Pubococcygeal Line (PC line) and the Ischial Point (I point) as well as the perineal

skin. Rectal gas located below the PC line or less than 1 cm from the skin of the

perineum (identified by a radiopaque marker placed in the gluteal cleft or anal

dimple) is indicative of a low anomaly and gas above the PC line or more than 1 cm

from the perineum is considered a high anomaly2. 9, 11.

This investigative modality has its shortcomings , positioning is uncomfortable and

time consuming to achieve, constant crying during the procedure causes contraction

of the puborectalis sling and hence deceptive obliteration of the lower rectum, the

rectum may be pulled cephalad due to gravity in the inverted position depicting a

false higher level of gas shadow9, ,21.

21 2. The Prone Cross Table Lateral radiograph was developed in 1973 which placed the

infant in a more comfortable position (prone with the hips flexed and elevated up to

45 degrees ) hence eliminating the above shortcomings9,21. A lateral radiograph is

taken with the patient in the prone knee-chest position. The level of gas in the

terminal colon is compared to the landmarks (PC line and I point) as described for

the Lateral invertogram.

Prone Cross-table lateral Radiograph

FIG. 1

3. Augmented Pressure Colostography (Distal loopography) is further used to delineate

the level of the distal rectal pouch after an initial diverting colostomy has been

done2,22.Contrast is introduced under pressure into the distal loop of the colostomy,

to outline the anatomy of the terminal colorectum and identify the presence or

otherwise of a fistula. This level is related to that of the PC line, which lies

approximately at the level of the levator ani muscle.

22 FIG 2

Pressure Augmented Distal Colostogram

4. Transperineal ultrasonography is a non-invasive method of determination of the level

of the distal rectal pouch and identification of fistulae2, 6, . The rectal pouch is

identified in relation to the perineum. Infracoccygeal Ultrasonography, however

identifies the puborectalis muscle as a hypoechoeic U–shaped band at the level of the

23 anorectal flexure. If the distal rectal pouch is seen passing through the puborectalis it

is considered a low anomaly. If it is identified within the muscle sling, it is

interpreted as an intermediate anomaly and if it is not visualized within the sling, it is

considered a high anomaly.

5. Computerized Tomography (CT) scan is an imaging modality increasingly in use in

the diagnosis of these anomalies2,23. Multidetector CT allows for multiplanar

imaging by showing increased details of bony structures and demonstrating pelvic

musculature. Its limited contrast resolution however is unable to distinguish

meconium from the adjacent rectal wall and musculature. It has been used in

detecting the level of the terminal colorectum but is not useful in detecting the site of

fistulae.

6. Magnetic Resonance Imaging (MRI) offers similar visualisation of features

described above, with the added advantage of fistula imaging without the potential

hazards of irradiation2, 6, 11, 23.

In our environment the commonly used modalities are Cross table lateral radiography and distal loopography for reasons of easy availability and simplicity. Transperineal ultrasonography despite its advantages requires necessary expertise which has reduced its availability as an investigative modality. Cost constraints have been a limiting factor in the widespread use of CT and MRI in diagnosis of Anorectal anomalies in our environment.

It is also important to document or exclude the presence of associated anomalies eg. the

VACTERL association using one or more of the following investigations; Lumbosacral spine radiographs, Abdominal Ultrasound scans, Micturating Cystourethrograms and

Echocardiography.

24

2.5 VERTEBRAL ANOMALIES

As earlier stated several vertebral anomalies have been identified to be associated with

Anorectal malformations1, 11, 24. Spinal deformities are said to be the most commonly associated malformations with ARM. These include hemivertebrae, bifid vertebrae, sacral agenesis, hemisacrum, scoliosis as well as presence of extra or absent ribs16, 17.

Heij et al reported the presence of spinal anomalies in the lumbosacral region in 46.5% of patients with ARM and recommended routine MRI for the investigation of all these patients16. However in our environment the cost of this modality may limit its adoption.

The Sacral Ratio is used as a tool to evaluate sacral development and hence predict the likelihood of continence in these patients. It is calculated by measuring the distance from the lowest point of the sacrum to the lowest point of the sacroiliac joint and dividing this by the distance from the iliac crest to the lowest point of the sacroiliac joint in AP and Lateral

X-ray views of the pelvis.1,2,18

Generally the normal Sacral Ratio in the anteroposterior projection of a plain pelvic radiograph is 0.74 while in the lateral projection is 0.77.This value in the lateral projection is said not to be affected by pelvic tilt and hence to be more reliable. Low Sacral Ratio values(<0.52) correlate well with spinal cord anomalies and with unfavourable functional prognosis in children with Anorectal anomalies. Ratios that approach 1.0 usually predict a good prognosis. With respect to continence, however patients with ratios less than 0.3 are universally incontinent1, 2,18,23,25.

Carson et al evaluated the neurologic implication of sacral abnormalities in relation to ARM, particularly Anorectal agenesis without fistula24. The presence of a hemisacrum is said to be

25 usually associated with a presacral mass, it is also found with Anorectal agenesis without fistula. Hemivertebrae affecting the lumbar and thoracic spine have been reported, giving rise to a lordosis as against the more commonly occurring scoliosis8, 26.

Karrer et al27 also evaluated associated spinal dysraphic syndromes found in ARM, highlighting the accuracy of spinal ultrasonography in identifying tethered cord in the neonatal period. The use of this non-invasive modality in early screening was suggested.

Similar studies were also done by Denton who however focused on those found in association with Anorectal agenesis without fistula variety25, 28.

In the series of Macedo et al , using the Pena criteria, assessing Sacral Ratios and faecal incontinence, the opinion was that Sacral Ratios were not completely reliable in predicting continence and as such should be interpreted cautiously.29

Similarly, Warne S.A et al in studying the Validity of Sacral Ratios concluded that though

Sacral Ratios had good inter- and intra-observer repeatability, it has limited value in discriminating a normal from an abnormal sacrum.25

26

FIG 3 a) AP measurement of Sacral Ratio (YZ/XY) X

Y

Z

b) Lateral measurement of Sacral Ratio (YZ/XY) FIG 4

X

Y

Z

27

2.6 SURGICAL INTERVENTION

Surgical intervention has ranged from rupturing of an obstructing membrane with a finger or point of a knife, to making an incision in the perineum to “find” the bowel1, 2.

In 1783, the first inguinal colostomy was performed but many infants died thereafter. The

1700’s and 1800’s ushered in the suggestion of opening the peritoneum if the bowel was not accessible from below while single stage abdominoperineal procedures were popularized in

1879 by McLeod , usually involving resection of the rectosigmoid. By this era most textbooks recommended the fashioning of a colostomy for emergency cases, presenting as intestinal obstruction with abdominal distension and perineal procedures for all other cases2.

In 1950, Denis Browne popularized the cutback anoplasty for perineal fistulae. Stephens in

1971 in comparing normal anatomy with that found in ARM emphasized the preservation of the puborectalis sling as important for continence. Pena, a year later however described the composite Striated Muscle Complex (consisting of the Deep External Anal Sphincter,

Puborectalis sling- which is a part of Levator ani, and the Superficial External anal

Sphincter) as against a solo puborectalis sling2, 11.

Various procedures exist, depending on the type of anomaly. These include an Anoplasty,

Anal transposition, Abdominoperineal pull-through, Abdominosacroperineal pull-through and the Posterior Sagittal Anorectoplasty (PSARP) popularized by Pena2, 11. The Sphincter

Saving Anorectoplasty(SSARP)has also been described by Pratap and co-workers30 in 2007.

It involves a subcoccygeal approach which avoids division of the skin and levator muscle in the midline. It was employed in the treatment of twenty-six male patients with high ARM.

28 These may be staged, with an initial diverting colostomy (divided descending colostomy preferred) in the high and intermediate varieties without fistula. A single stage definitive surgery can also be done and this is currently being embraced 31, 32. The Laparoscopy- assisted pull-through is also gradually gaining popularity.33 34

29 CHAPTER THREE

OBJECTIVES

This study seeks to determine the prevalence of associated vertebral anomalies in Anorectal malformations presenting at LASUTH and determine the relevance of Sacral Ratios in predicting the outcome of these patients.

Specific

1) To determine the prevalence of Anorectal malformations in Lagos State University

teaching Hospital (LASUTH) during the period of study.

2) To document the number and types of vertebral anomalies associated with Anorectal

malformations in the study population.

3) To measure the Sacral Ratios of patients in the study population.

4) To compare the findings of this study with similar pre-existing studies in the

literature as well as adding to the existing body of knowledge of this patient group in

our environment.

30 CHAPTER FOUR

METHODOLOGY

This was a prospective cross sectional descriptive study carried out at the Paediatric Surgery unit of the Lagos State University Teaching Hospital (LASUTH), Ikeja, Lagos from May

2010 to July 2011. The Ethical committee of the institution approved this study and informed consent was obtained from the parents/guardians of the participating patients.

The Paediatric surgery unit (Consultants, Residents, House officers) and nurses involved in the care of these patients were notified of the study. The Radiology department of the institution was also informed.

Data in the proforma was obtained by the author both at the outpatient clinic and on the ward. The author was also involved directly in the clinical evaluation, operative treatment and post operative care and follow-up of most of the patients in the study group. The lumbosacral radiographs were taken at the Radiology Department of the institution. The measurements of the sacral ratios were done by the author while assessment of the radiological findings was carried out by a Consultant Radiologist along with the author.

PATIENTS

4.2 Sample size

The sample size was calculated using the formula

N= Z²pq

d2

Where N = Sample size

31 Z =Standard normal deviate corresponding to level of significance at 95% ( standard value of 1.96)

p = estimated prevalence (obtained during a pilot study at the institution) = 3%= 0.03

d = precision (proportion of sample error = 0.05

N = (1.96)² ×0.03 × 1-0.03)

0.05²

= (3.84 x (0.03 x 0.097) = 44

0.0025

N.B

P = Estimated prevalence was obtained from a pilot study of Anorectal malformations seen at LASUTH. In the study a total of 643 new cases presented to the Paediatric surgical outpatient clinic and Children emergency department from December 2009 to April 2010.

Of this number 20 were Anorectal malformations hence an estimated prevalence of 3 in

1000 patients (i.e 0.03).

The minimum sample size of 44 was used for this study as further recruitment of patients would have resulted in an inability to complete necessary investigations and surgical intervention within the study period.

32 4.2.1 INCLUSION CRITERIA

1) Patients aged 10 years and below

2) Both male and female patients within the above age group.

3) Patients with all varieties of Anorectal malformations.

4) Patients seen after neonatal Colostomy but prior to definitive abdomino-perineal pull

through or PSARP.

4.2.2 EXCLUSION CRITERIA

1) Patients with history of pelvic fracture.

2) Patients above the age of 10 years.

4.3 METHODS

All patients presenting with an anorectal malformation within the study period were examined fully after a detailed history was taken. Particular attention was paid to the perineum which was examined in good light. The anomalies were classified using the

Wingspread system.

Further clinical examination was carried out to identify the presence or otherwise of associated anomalies – VACTERL, these were further evaluated by Lumbosacral radiographs, abdominal ultrasonography and 2-D Echocardiography.

33 The lumbosacral radiographs were obtained at no cost to the patients as the institution operates a free health scheme for paediatric patients 12years and below which covers certain investigations.

Necessary data were collected using a proforma (see appendix).

Preoperative protocol used for ARM patients.

Ward admission

History taking and full physical examination / thorough perineal examination

Prone cross table lateral radiographs where applicable.

Lumbosacral radiographs Anteroposterior and Lateral views.

Abdominal Ultrasonography

Echocardiography

Micturating Cystourethrography or Expression Cystourethrography

Sigmoid Defunctioning Colostomy for those presenting with intestinal obstruction

Distal Colostogram

PSARP for intermediate and low anomalies

AP Pull through for high anomalies

34 Obtaining Plain Lumbosacral Radiographs

Plain radiographs of the Lumbosacral spine were taken in both the Anteroposterior and

Lateral projections.

Anteroposterior projections were taken with the patients hips in extension; this occasionally required the assistance of a protected adult when dealing with infants and neonates.

Lateral projections were taken with the beam centered on the greater trochanter. To ensure true lateral radiographs, patient’s thighs were strapped such that they overlapped each other.

Poor quality radiographs could not be used for the measurements. Repeated attempts to get better quality radiographs were limited to discourage undue irradiation, moreover the use of several films for a single patient was considered a poor management of available resources.

Measurement of Sacral Ratios

SR was measured both in the Anteroposterior and Lateral projections of the Lumbosacral radiographs by the following method.

Three horizontal lines were drawn. One through the highest point of the right and left iliac crests (line X). The next through the lowest points of the right and left sacroiliac joints(line

Y) and the third through the tip of the coccyx (if it has ossified ) or the lowest point of the sacrum, perpendicular to the vertical axis (line Z).

These three lines were checked to be parallel to each other. SR was calculated using the formula YZ / XY. In interpreting SR measurements the Pena criteria was considered – normal SR 0.74 in anteroposterior films and 0.77 in lateral films.

35 4.4 DATA STATISTICAL ANALYSIS

Data were entered into the Microsoft Excel spreadsheet and exported into the Statistical

Package for Social Sciences Software (SPSS) version 16.0 .

Descriptive and inferential statistics were applied in the course of analysis. Proportions and percentages were calculated for categorical variables.

Minimum, maximum, and mean + standard deviation were appropriately applied in the course of analysis.

Pearson’s Chi-square test (a non-parametric inferential statistical procedure) was used to assess relationships and statistical significance between patient’s characteristics.

P-value less than 0.05 was considered to be statistically significant (95% confidence level).

36 CHAPTER FIVE

RESULTS

A total of 44 old and new patients with Anorectal malformations were seen in the Paediatric surgery unit at LASUTH between May 2010 and July 2011 and included in the study. This constitutes 1.56% of the total number of patients seen. The minimum age was 1 day old, while the maximum was 7 years. The mean age + SD were 7.56 + 16.05 months. Thirty one

(70.5%) of the children were less than 1 year old, Twelve (27.3%) were 1 – 5 years, while only one child (2.3%) was older than 5 years of age.

Twenty-one (47.7%) were male and twenty-three (52.3%) were female (Table I). More male patients (90.5%) presented via the Children Emergency, compared to the females (17.4%).

More female patients (82.6%) were referred from various health facilities.

Of the 44 patients in this study, 14 patients (31.8%) had low anomalies, 17 (38.6%); intermediate, while 13 patients (29.5%) had high anomalies. (Table II)

In all, Anorectal agenesis with Rectovestibular fistula was the most frequent anomaly seen.

Vertebral anomalies were noted in 10 patients (22.7%) and included hemivertebrae, which was present in 2 patients (4.5%), bifid vertebrae present in 8 children (18.2%). Sacral agenesis was also noted in one of the patients with hemivertebrae. Other malformations observed included; Lumbarization of the first Sacral vertebra (S1), Fusion of the fourth and fifth lumbar vertebrae (L4 & L5), Spina bifida occulta, and a defective spinous process of the 5th Lumbar vertebra.(Table III,FIG 5).

Associated Urologic abnormalities noted included Bilateral Vesicoureteric reflux, renal hypoplasia, undescended testis and one patient had Crossed renal ectopia, diphallus with

37 double urethra. Cardiac anomalies were seen in 4 patients (9.1%) and one patient had Right tibial hemimelia with medial polydactyly of the left foot.(Table IV,FIG 6, FIG 7, FIG 8)

Sacral Ratios were calculated in both anteroposterior and lateral views of plain lumbosacral radiographs of forty-three patients. The minimum Antero-posterior Sacral Ratio (APSR) was

0.54, while the maximum was 1.00. The mean APSR + SD were 0.70 + 0.78. Thirty-one

(72.1%) of the children had abnormal (< 0.74) Antero-posterior Sacral Ratio, while twelve

(27.9%) that had normal (> 0.74) APSR.

The minimum Lateral Sacral Ratio (LSR) was 0.56, while the maximum was 0.90. The mean LSR + SD were 0.76 + 0.71. Abnormal (< 0.77) Lateral Sacral Ratio was computed in eighteen (41.9%) of the children, compared to twenty-five (58.1%) that had normal (> 0.77)

LSR.

The Anteroposterior Sacral Ratio did not have a significant effect on the outcome (p-value =

0.958) neither did the Lateral Sacral Ratio value (p-value = 0.943).

Twenty-one (80.8%) of the patients with abnormal Anteroposterior Sacral Ratio as well as twelve patients with abnormal Lateral Sacral Ratios had a good outcome (Tables II).

Underwear soiling was noted in two (20%) of the patients with normal APSR and four

(19%) of those with normal LSR (FIG 9, FIG 10).

Treatment offered to these patients varied depending on the type of anomaly and presentation of the patient. Ten patients (22.7%) had primary PSARP, Five ( 11.4%) had

Anoplasties. Others had either a PSARP or AP – Pullthrough after an initial Sigmoid defunctioning Colostomy. (Table V)

Of the complications of treatment that occurred during the study period, Anal stenosis was the most common. (Table VI). The patient with a complete anoplasty breakdown leading to a failed primary PSARP subsequently had a Sigmoid defunctioning colostomy and a re-do

PSARP thereafter.

38 The type of anomaly did not have a significant effect on outcome. (p-value = 0.324, Table

VII, FIG 11)

Patients who still had a colostomy at the time of conclusion of the study (eight patients) could not be assessed for outcome.

Patient’s outcomes were deemed good if they had voluntary bowel movements and remained clean between bowel motions in contrast to those who soiled their underwear. For patients less than three years old, one to three bowel motions a day associated with awareness during the act of defaecation as well as remaining completely clean between bowel motions were considered to have a good outcome. Anorectal manometry and Electromyography are more objective means of assessment of continence in ARM patients, however these are not available in our environment hence the adoption of this rather subjective method.

39 TABLE I

Patients’ characteristics

Frequency Percent (%)

Age (year)

< 1 year 31 70.5

1 – 5 years 12 27.3

> 5 years 1 2.3

Sex

Male 21 47.7

Female 23 52.3

Mode of presentation

Emergency 23 52.3

O.P referral 21 47.7

Prior surgery

Had 1 2.3

Not had 43 87.7

40 TABLE II

Type of anomaly and sacral ratios evaluation

Frequency Percent (%)

Type of anomaly

Low 13 29.5

Intermediate 17 38.6

High 14 31.8

Sacral agenesis

Yes 1 2.3

No 43 97.7

Sacral Ratio Antero-posterior (APSR)

< 0.74 (abnormal) 31 72.1

> 0.74 (Normal) 12 27.9

Sacral Ratio Lateral (LSR)

< 0.77 (abnormal) 18 41.9

> 0.77 (Normal) 25 58.1

Outcome

Good 29 80.6

Underwear soiling 7 19.4

41 TABLE III

Distribution of vertebral characteristics and limb malformations among patients

Frequency Percent (%)

Hemi – vertebrae

Present 2 4.5

Not present 42 95.5

Bifid - vertebrae

Present 8 18.2

Not present 36 81.8

Extra rib

Not present 44 100.0

Absent rib

Not present 44 100.0

Scoliosis

Yes 2 4.5

No 42 95.5

Other malformations

Lumbarization S1 1 16.7

Fusion of L4 & L5 1 16.7

Spina bifida occulta 1 16.7

Widened L4/5; L5 defective 1 16.7

Rt tibial Hemimelia + Polydactyl Lt Foot 1 16.7

42 TABLE IV

Distribution of other associated anomalies among patients

Frequency Percent (%)

Other associated anomalies

Congenital heart 4 9.1

Undescended testis 3 6.8

Hypoplastic Rt kidney 1 2.3

Coronal hypospadias 1 2.3

Bilateral VUR 1 2.3

Diphallus / double urethra /crossed renal ectopia 1 2.3

43

FIG 5 Plain Radiograph showing Scoliosis with Hemivertebra

44

FIG 6 Diphallus with double urethra

45

FIG 7 Diphallus with double urethra (lateral view)

46

FIG 8 Intravenous Urogram showing crossed renal ectopia

47 TABLE V

Distribution of treatments offered to patients

Frequency Percent (%)

Treatment

Sigmoid colostomy & PSARP 13 29.5

Primary PSARP 10 22.7

Sigmoid colostomy 8 18.2

Sigmoid colostomy & AP pullthrough 8 18.2

Anoplasty 5 11.4

48 TABLE VI

Distribution of Complications among patients

Frequency Percent (%)

Complications

Anal stenosis 2 22.7

Anoplasty breakdown 2 22.7

Paracolostomy hernia 1 11.1

Superficial wound dehiscence 1 11.1

Rectovestibular fistula 1 11.1

Rectourethral fistula & anal stenosis 1 11.1

Urinary retention 1 11.1

49 TABLE VII

Association of Outcome with Antero-Posterior Sacral Ratio (APSR), Lateral Sacral

Ratio (LSR) and Type of Anomaly

Good Underwear Total P–value (X²)

soiling

n (%) n (%)

APSR Abnormal (< 21 (80.8%) 5 (19.2%) 26 0.958

0.74)

Normal (> 0.74) 8 (80.0%) 2 (20.0%) 10

Total 29 (80.6%) 7 (19.4%) 36

LSR Abnormal (< 12 (80.0%) 3 (20.0%) 15 0.943

0.77)

Normal (> 0.77) 17 (81.0%) 4 (19.0%) 21

Total 29 (80.6%) 7 (19.4%) 36

Type of Low 13 (92.9%) 1 (7.1%) 14 0.324 anomaly

Intermediate 10 (71.4%) 4 (28.6%) 14

High 6 (75.0%) 2 (25.0%) 5

Total 29 (80.6%) 7 (19.4%) 36

P-value not significant at 95% confidence level with Pearsons Chi-square test (X²).

50

Association of Outcome with Antero-Posterior Sacral Ratio (APSR)

FIG 9

51

Association of Outcome with Lateral Sacral Ratio (LSR)

FIG 10

52

Association of Outcome with Type of Anomaly

FIG 11

53 CHAPTER SIX

DISCUSSION

Anorectal malformations form a significant group of congenital anomalies encountered by

Paediatric surgeons worldwide. It is a complex group of abnormalities relating to the formation of the anorectum. Their incidence has a geographical variation 5, ranging from 1 in 1500 to 1 in 5000 live births 1,2,35. In Africa they constitute a significant surgical load and have been identified as representing 13.4 - 20% of congenital malformations 5 and 67% of neonatal emergency surgical procedures 36.

The slight male preponderance documented in most other series 1,2,6,25,35, was not observed in this study but rather a reverse. This finding is however similar to that of Archibong et al15 in Calabar, Nigeria.

The occurrence of associated anomalies has been well documented, necessitating a recommendation of a routine search for them among this patient population37. Vertebral anomalies have been reported as the most commonly associated anomaly 2, 14, 26, 38.The findings in this study reflect the same with 10 patients (22.7%) affected, however in certain other series, urogenital anomalies were found to be the most frequently associated 3, 4, 7, 15, 16,

17. In this study Urogenital anomalies were seen in 7 patients (15.9%).

The frequency of occurrence of associated anomalies particularly sacral vertebral, has prompted the recommendation that all patients with anorectal malformations be routinely screened using MRI to identify them 16. This however does not have universal acceptance.

Within this series plain lumbosacral radiographs taken in anteroposterior and lateral views were used to identify any abnormalities and to measure Sacral Ratios.

54 The variety of vertebral anomalies in this study is similar to that seen in other studies

14,16,26,38 however further characterization was not undertaken due to the cost it would have incurred.

The aim of management in patients with anorectal malformations is beyond the creation of an anatomic neoanus. It should be one that is suitable for the regular passage of faeces and well positioned relative to the sphincter system/ striated muscle complex to ensure continence. Some patients despite appropriate surgical intervention do not achieve full continence 29; abnormalities of the sacral vertebrae in particular have been implicated as part of the reason for this. It is based on the understanding that such abnormalities of hypodevelopment are frequently accompanied by defective sacral nerve root development2,

29. Assessment of the lumbosacral vertebrae is hence of importance. Pena in 1995 proposed what would be described as an objective means of assessing possible changes in the lumbosacral spine 10. This involved measurement of the Sacral Ratios which was then used to predict which patients would be more likely to develop faecal incontinence. The cutoff value of the SR in the anteroposterior and lateral views ( Penas criteria) are 0.74 and 0.77 respectively 10, 25, 29

Among the forty-three patients whose sacral ratios were measured, none had SR of less than

0.52, unlike in the series of Ahmadi et al, in which this subset of patients were further evaluated for tethered cord using MRI and untethering yielded some improvement in outcome33.

The only patient with Sacral agenesis in this study had an abnormal sacral ratio, however was not further evaluated for tethered cord.

Like previously reported series 18,25,29 , there was no significant correlation between the SR and outcome i.e continence. Thus a SR less than “normal” by Pena’s criteria does not on its

55 own predict likelihood for incontinence or soiling. The SR was found to be useful as a pointer to lumbosacral abnormalities by Warne et al25. The previous reports used a single view of the radiographs to arrive at their conclusion for reasons relating to the quality of the films 29 and difficulty in achieving a true lateral position 25.This study utilized SR obtained in both AP and Lateral views . Both the APSR and LSR did not have a significant effect on predicting outcome.

Other factors which would probably affect the outcome following surgery for ARM includes the type of anomaly i.e. low anomalies are documented to generally have a higher possibility of continence. They are however known to suffer more from constipation resulting from a megasigmoid or rectum. They may soil their underwear, but as a result of “overflow” incontinence. This can be managed by rectal washouts, dietary modifications and the use of laxatives. The surgery /operative procedure may also affect outcome, an abdominoperineal pull through which involves more dissection than an anoplasty runs a greater risk of resulting in inadvertent damage to the striated muscle complex/sphincter system resulting in incontinences post operatively. The expertise or lack thereof of the surgeon may also contribute to possible damage. The presence or absence of any associated neurological defect as well as the anatomic level of the Anorectal anomaly were however identified as the main determinants of outcome in the series of Ackroyd et al. The type of operative procedure appeared to be of less importance39.

In this study, the type of anomaly did not have a significant effect on outcome (p=0.324) though more patients with low anomalies had a good outcome. This suggests that an interplay of the various factors mentioned contribute to the overall outcome of management of patients with Anorectal malformations.

56 In this study, the chance of having a good outcome reduced as the severity of the anomaly increased. On the other hand, the occurrence of underwear soiling increased as the severity of the anomaly increased. The value of Sacral Ratios, be it Anteroposterior or Lateral, were not reliable predictors of either outcome.

.

57 CHAPTER SEVEN

CONCLUSION AND RECOMMENDATIONS

In conclusion, ARM though generally reported as rare, was seen in an unusually higher degree in our centre. Vertebral and urogenital anomalies are a common and significant association in patients with ARM. This study also suggests that the Sacral Ratio though more objective than the mere counting of the sacral vertebrae, is not fully reliable in predicting the outcome of management of patients with ARM.

.

Recommendations

Bearing in mind the findings of this study, the following are recommended.

1. There should be concerted efforts on creating awareness of this group of anomalies at

the primary heath care level. Medical personnel should ensure that newborns are

examined thoroughly prior to discharge and parents of children with ARM should be

made to understand that these anomalies can be managed in our environment.

2. There should be routine screening of this subset of patients for associated anomalies,

particularly vertebral and urogenital. Possible subsidy on the cost of investigations

necessary for this would be welcome from the government and non-governmental

organizations alike.

3. Proper and adequate detailed interaction with and counseling of parents of this group

of patients cannot be overemphasized. This would discourage false expectations and

encourage parents’ participation in the long term care of their children or wards.

58 4. A multicentre prospective long term study on this subject matter is encouraged.

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64 APPENDIX

PROFORMA

Age……………………..

Sex……………………...

Mode of presentation

Emergency

Outpatient referral

Prior surgery Yes No

Type of Anomaly

High

Intermediate

Low

Radiographic Findings

65 Hemivertebrae

Bifid Vertebra

Extra Rib

Absent rib

Scoliosis

Sacral Agenesis

Sacral Ratio

AP……………………

Lateral………………..

Others (Specify)

Other Associated Anomalies……………………………

Treatment Offered………………………………………

Complications ………………………………..

Outcome …………………………………………..

66 APPENDIX

INFORMED CONSENT FORM (LREC/10/08/145)

I …………………………………………Of ………………………………………………… hereby consent to the inclusion of my child/ ward in the study being conducted.

Dr ………………………………… has explained the process involved to me. I understand that the study is solely for the purpose of medical research and I am willing to allow my child/ ward to act as a volunteer for that purpose on the understanding that I shall be entitled to withdraw this consent at any time. I also recognize that the results of the study may be of significant benefit to mankind.

Date ………………………… Signed ……………………………..

……………………………………………

(Witness to the parent’s/guardians signature)

I confirm that I have explained to the parent/ guardian the purpose and nature of the study, including the fact that his/ her refusal to participate will not in any way affect the care of his/ her ward by me or any other member of the institution .I know the consequences of any false declaration on this or any other form.

Date ……………………….. Signed ………………………………..

(Doctor)

67

68