Persistan
Kloakada Spinal Disrafizm:
Rutin Manyetik Rezonans İnceleme Gerekli mi?
Aydın YAĞMURLU*, Hüseyin DİNDAR*, Bahri KEYİK**, İ. Haluk GÖKÇORA*
* Ankara University School of Medicine, Department of Pediatric Surgery,
** Ankara University School of Medicine, Department of Radiology, ANKARA
ÖZET
Gebeliğin 35. haftasında 2580 gram ağırlığında doğan kız bebek fizik muayenede tesbit edilen anal atrezi nedeniyle kliniğimize getirildi. Yapılan sistoskopide persistan kloaka olduğu saptanan hastaya ileostomi yapıldı. 1 yaşında yapılan magnetik rezonans görüntüleme (MRG) incelemesinde spinal disrafizm: filum terminale seviyesinde kord lipomu, tethered kord ve pelvik taban adelelerinin hipoplazik olduğu saptandı. Posterosagittal anorektoplasti, kolovajinoplasti ve mesane boynu rakonstrüksiyonu yapılan hastanın ameliyat sonrası herhenginbir problemi olmadı. MRG yöntemiyle tanı alan spinal disrafizm ve kord lipomu eşlik eden bir persistan kloaka olgusunu sunarak bu tip anorektal malformasyonlara eşlik eden yandaş anomalilerin tanısında konvansiyonel yöntemlerle MRG’yi karşılaştırmayı amaçladık.
Anahtar Kelimeler: Persistan kloaka, spinal disrafizm, manyetik rezonans görüntüleme
SUMMARY
Persistant Cloaca Associated with Spinal Dysraphism: Is Routine Magnetic Resonance Imaging Necessary?
A 2580 g weight girl was born after the 35th gestational week. Anal atresia was immediately detected at first physical examination. Cystoscopy revealed a persistent cloaca and an ileostomy was performed. MRI demonstrated spinal dysraphism, lipoma in the level of filum terminale, tethered cord syndrome and hypoplasia of the pelvic muscles at 1 year of age. A posterior sagittal anorectoplasty with pull-through, colovaginoplasty and bladder neck reconstruction was performed. The postoperative course of the patient was uneventful. We here present a patient with persistent cloaca whom we have obtained spinal dysraphism and cord lipoma using.
Key Words: Persistent cloaca, spinal dysraphism, magnetic resonance imaging
INTRODUCTION
Congenital anorectal malformations are found in many forms, and frequently associated with other anomalies, especially of the spinal cord, spine and the urogenital system (1). The finding of one anomaly requires an evaluation of the other systems. In addition to malformation of the bony spine and abnormalities of the sacral nerves, other neurological deficits are sometimes seen in patients with anorectal anomalies and the association of anorectal malformations with dysraphic lesion of the spinal cord is being recognized. Spinal dysraphism includes congenital spinal anomalies resulting from improper midline fusion of bony, mesenchymal and neural structures such as intraspinal masses, lipomyelomeningoceles, tethered cord, and occult meningocele (1). The early recognition and treatment of correctable lesions of the terminal spinal cord in patients with anorectal malformations may preserve important neurologic function (1).
Imaging examinations plays a key role in defining and establishing the multiple aspects of these complicated anomalies. Invertography, cistourethrography, ultrasonography, computerized tomography (CT) and magnetic resonance imaging (MRI) have all been used (1).
We here present a patient with persistent cloaca whom we have obtained spinal dysraphism and cord lipoma using MRI.
CASE
A 2580g weight girl was born after the 35th gestational week. The APGAR scores were 5 and 7 at one and five minutes respectively. Anal atresia was immediately detected at first physical examination. The external genitalia was concordant with female phenotype. There was only one opening, and she passed urine and meconium from this site. Direct X-ray showed mild distension of the abdomen. Cystoscopy revealed a persistent cloaca and an ileostomy was performed immediately. At 6 months X-ray using a radiocontrast material showed an unique opening of uterus, bladder and rectum. MRI demonstrated spinal dysraphism, lipoma in the level of filum terminale, tethered cord syndrome and hypoplasia of the pelvic muscles at 1 year of age. Also the hypoplasia or may be aplasia of pelvic floor muscles was demonstrable with MRI. In our patient we have obtained the low lying conus medullaris in the level of 3rd and 4th lumbar vertebras ending as hemicord (Figure 1). There was a lipoma distally filum terminale. On the pelvic floor, there was lipomatous structures in the location of rectum instead. There were no pubolevator muscle groups. Also SMC were absent on MRI (Figure 2). Though on operation, levator and puborectal muscles were hypoplasic, a posterior sagittal anorectoplasty with pull-through, colovaginoplasty and bladder neck recontruction was performed. The postoperative course of the patient was uneventful.
DISCUSSION
The exact frequency with which a dysraphic lesion of the spinal cord occurs in patients with malformations of the anorectum is not known. According to different authors, its incidence differs from 6% to 9%. Spinal dysraphic syndromes are a group of malformations charecterized by incomplete closure of the primitive neural tube. Occult spinal dysraphism includes tethered cord, diastematomyelia, neuroenteric cysts and lipomas (2). Tethered cord syndrome refers to an association of neurologic deficits involving the lower extremities and sphincters and a low lying conus medullaris (4). Yamada et al (5). postulated that the fastening of the conus by a thick filum terminale or lipoma to the sacrum results in a dysfunction of oxidative metabolism of the lumbosacral neurons.
The development of abnormal reflexes, motor or sensoral deficit, or incontinence are suggestive of this syndrome. Unfortunately the onset and/or progression of neurologic symptoms is often very gradual and may easily be overlooked. Enuresis or stool incontinence may incorrectly be attributed to the pullthrough procedure (2).
In our patient the presence of spinal dysraphism (hermicord, tethered cord and cord lipoma) was obtained preoperatively. The existence of normal neurologic functions make neurosurgeons not to think on operation side. But the consensus on this subject is the indication of intervention even in asypmtomatic patients with spinal dysraphism, because the natural history of tethered cord is one of deceptively gradual worsening to a fixed neurologic deficit (2,3,6). Therefore, early recognition and treatment of correctable lesions of the terminal spinal cord is essential to preserve important neurologic function.
Preoperative imaging of the anorectal malformation is essential to decide the type of operation, and define and establish multiple aspects of these complicated anomalies. Invertography, cictourethrography, ultrasonography, CT and MRI have all been used (3).
Although the anatomic level of malformation is important, it is essential to identify the various components of the anomaly. The radiologist has to provide informative imaging about:
1. Associated anomalies
2. Presence of rectal fistula
3. Distance between rectal pouch and anal dimple
4. Development of striated muscle complex (SMC), levator ani, and parasagittal fibers
5. Position of the cross between parasagittal fibers and vertical fibers (included SMC) where the neo-anorectum will be positioned (3).
The plain sacral radiographs can demonstrate spina bifida, abnormal spinal curve, hemivertebrae, or diastematomyelic spurs, however plain radiographs of the infant spine may be inadequate due to incomplete ossification. Our patient did not have any evidence of the pathologies listed above in plain x-rays.
High resolution ultrasonography is a rapid, safe, noninvasive method of evaluation that is applicable to this subgroup of patients because of the associated acoustic window provided by the spina bifida and incomplete ossification of the posterior elements in infants (1-3). It can be done at the bed side and does not require sedation. However we could not be able to perform ultrasonography.
The gold standard for imaging spinal dysraphism is CT with metrizamide myelography, but it can be done in children older than 1 year of age (7). More recently, MRI has begun to supplant standard CT scanning. The advantages of MRI are the lack of ionizing radiation, and superb demonstration of anatomy and pathology in planes being impossible with CT. The disadvantages of MRI include the need for sedation and difficulties in imaging severe scoliosis (2,8).
Concerning CT and MRI, even if CT can provide a direct visualization of the sphincteric muscles, it is limited to transaxial plane. MRI imaging provides identification of both rectal pouch and sphincteric muscles in multiple planes without risk of ionizing radiation. Determination of the rectal pouch level by MRI during sedation may be more accurate than conventional radiographic techniques. Furthermore, the SMC, levator ani and the various fibers can be exquisitely demonstrated with MRI in multiple planes and muscle size, morphology and location can be evaluated (2,3). We have obtained spinal dysraphism and hypoplasia of pelvic floor muscles by MRI successfully.
MRI has proven to be the only modality to answer all these crucial questions, and has contributed to a better insight in the morphology and pathogenesis of such complex congenital malformations. Therefore, we recommend that all patients with anorectal anomalies undergo MRI of pelvic structures for to avoid missdetection of occult spinal dysraphism, tethered cord syndrome and cord lipoma and to detect the correct anatomical position of rectal pouch and pelvic floor muscles.
REFERENCES
ADDRESS FOR CORRESPONDENCE:
Dr. Aydın YAĞMURLU
Ankara University School of Medicine
Department of Pediatric Surgery
ANKARA