Missed anterior sacral meningomyelocele presenting with obstructive uropathy

Abstract

A 2-month-old full-term female presented with a large anterior sacral meningomyelocele resulting in transient obstructive uropathy with bilateral hydronephrosis and acute kidney injury. After initial bladder decompression and surgical resection of the meningomyelocele, there was spontaneous resolution of bladder function confirmed with urodynamics. Anterior spinal meningomyelocele (ASM) is a rare neural tube defect that may present with urinary dysfunction secondary to compression of the bladder and sacral nerve roots or congenital defects to the bladder nervous supply. Obstructive uropathy due to ASM may spontaneously resolve after surgical resection.

Introduction

Anterior spinal meningomyelocele (ASM) is a rare form of spinal dysraphism in which the meninges herniates through the anterior sacral hiatus into the retroperitoneal and presacral space. Patients may present with postural headaches, abdominal or low back pain, bowel or bladder dysfunction, meningitis, or neuropathy.^1,2 Females can experience dysmenorrhea, dyspareunia, or dystocia.² It typically presents in adulthood, with the majority of cases diagnosed in the third decade.³ Surgical resection is recommended, although the neurological sequelae may be permanent.^2,3 A case of ASM with obstructive uropathy in a female infant is presented along with a discussion of implications for subsequent urinary function following surgical resection.

Case presentation

A 2-month-old full-term female weighing 6.9 kg with no past medical or surgical history presented to an outside hospital with nausea, vomiting, and straining with urination and bowel movements. Parents report that prenatal ultrasound suggested an ovarian cyst but were not told of any other abnormalities. Amniotic fluid levels were normal on prenatal ultrasound (US). No gross motor weaknesses were appreciated on physical examination. Labs were significant for elevated creatinine of 2.7mg/dL. Pyloric stenosis was ruled out by ultrasound. A renal/bladder US demonstrated a severely distended bladder with bilateral moderate hydronephrosis (Fig. 1). No hydroureter was seen. Spinal US demonstrated a cystic collection within the soft tissues at the level of the sacrum with probable sinus tract extending into the thecal sac (Fig. 2). Magnetic resonance imaging (MRI) of the abdomen and pelvis confirmed a large cystic structure in the presacral space with projections entering the sacral foramina consistent with an anterior meningocele or meningomyelocele; the rectum, uterus, and bladder were displaced anteriorly (Fig. 3). Patient was eventually discharged home with recommendations for follow up at our tertiary children's hospital. Foley catheter was left in place and creatinine nadired to 0.19mg/dL.

Fig. 1.

Renal ultrasound shows bilateral moderate hydronephrosis in sagittal sections of the right kidney (A) and left kidney (B). A distended bladder in the transverse (C).

Fig. 2.

Spinal ultrasound in the sagittal view (A) and transverse view (B) show cystic structures (*) in the spinal canal with extensions into the presacral region.

Fig. 3.

(A) T-2 weighted MRI of the abdomen and pelvis in the transverse view show the cystic structures of the spinal canal with projections into the presacral space (arrow). (B) In the sagittal view, the cystic structure measures 3.8 × 4 × 7 cm and communicates with the sacral thecal sac through several enlarged neuroforamina (arrow). (C) In the sagittal view, the bladder (*) can be seen with the Foley catheter being superiorly displaced by the meningomyelocele (arrow).

Her presentation, labs, and imaging were reviewed at length by a multidisciplinary team. The likely diagnosis was determined to be inconsistent with a sacrococcygeal teratoma. Tumor markers of AFP, CEA, CA-125 were all within normal range. She was subsequently taken to the operating room with pediatric general surgery and neurosurgery for a diagnostic laparoscopy and open resection of the anterior meningomyelocele. The large meningomyelocele was mobilized away from the sacrum, transected at the base, and the sinus projections were oversewn in a purse-string manner with polyglactin. Abdomen was closed in a usual sterile fashion. Final pathology was consistent with meningomyelocele with few foci of ectopic neuroendocrine, hemangiomatous, adipose, and epithelial glandular tissue.

On post-operative (POD) 2, the patient had spontaneous bowel movements without straining. Foley catheter was removed on POD 2 with post-void residuals (PVRs) measuring 10–21mL. Her estimated bladder capacity was 43mL. The patient was placed on a clean-intermittent-catheterization (CIC) schedule every 6 hours. A repeat renal bladder US demonstrated resolution of the bilateral hydronephrosis. A voiding cystourethrogram on POD 4 confirmed no evidence of vesicoureteral reflux. The patient was discharged on POD 5 with a creatinine of 0.15mg/dL.

By POD17, parents reported the patient had spontaneous voids with PVRs consistently <10mL. A urodynamics study confirmed no evidence of detrusor overactivity, detrusor-sphincter-dyssynergia, or incontinence. There was no loss of compliance with a maximum detrusor pressure of <5cmH2O. Patient was unable to void during the study. Bladder was emptied of 42mL contrast. Fluoroscopic images demonstrated a closed bladder neck and a smooth walled bladder without trabeculations. There was no evidence of vesicoureteral reflux. Since patient had clinically low PVRs, patient was taken off the CIC regimen.

Discussion

ASM is an exceedingly rare congenital neural tube defect, with fewer than 250 cases reported.⁴ More than 75% of cases reported were in females, though this has been attributed to pelvic examinations performed for symptomatic ASMs.² The mesoderm that form the vertebrae also give rise to the mesonephros, which explains why many defects are associated with urogenital abnormalities. This can be attributed either to pressure on the sacral nerve roots by the meningomyelocele or congenital defects in nerve supply to the bladder. In a case review of 125 cases of ASM by Oren et al., 8.8% presented with urinary retention, 8.8% with urinary incontinence, 5.6% with urinary frequency, 7.2% with urinary tract infection, and 12% with dysuria.² ASM can also cause detrusor-sphincter dyssynergia (DSD), which may result in upper tract dilation and high-pressure vesicoureteral reflux.^2,3 If untreated, the urological sequelae of NTDs can lead to significant morbidity and mortality.

Early identification of ASMs and treatment is key to prevention of permanent urologic sequalae. Conservative management strategies include clean intermittent catheterization for detrusor and sphincter inactivity or oxybutynin for detrusor overactivity. This combination has been shown to dramatically improve detrusor compliance and resolve vesicoureteral reflux.⁵ Surgical repair has been generally shown to improve urological function, though the degree of improvement varies with different types of NTDs.⁵ While it is clear there is substantial variation in the urological presentation of ASM, no data currently exists on the long-term urological outcomes of ASM or the efficacy of conservative versus surgical management. Given that surgical correction of ASM is recommended to prevent progression of neurological dysfunction, these patients should be followed postoperatively to manage any long-term urologic sequelae.

Conclusion

Anterior spinal meningomyelocele is a rare condition and can be diagnosed with appropriate history, physical examination, and adjunctive imaging. It can result in obstructive uropathy, but after surgical resection, spontaneous resolution of the bladder dysfunction can be assessed with urodynamics. Patients should be followed after surgical resection, as there may be residual long-term bladder dysfunction.

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Declaration of competing interest

None.