Congenital spinal lipomas of the conus (SLCs)

Transcription

1 J Neurosurg Pediatrics 13: , 2014 AANS, 2014 Spontaneous improvement in urological dysfunction in children with congenital spinal lipomas of the conus medullaris Report of 2 cases Jetan H. Badhiwala, B.H.Sc., 1 Eric M. Thompson, M.D., 2 Armando J. Lorenzo, M.D., M.Sc., 3 and Abhaya V. Kulkarni, M.D., Ph.D. 2 1 Michael G. DeGroote School of Medicine, McMaster University, Hamilton; and Divisions of 2 Neurosurgery and 3 Urology, The Hospital for Sick Children, University of Toronto, Ontario, Canada Congenital spinal lipomas of the conus (SLCs) are among the most common closed neural tube defects. The treatment of SLC is an area of controversy because the true natural history of this condition is unknown. Here, the authors present two cases of SLC presenting in infancy with compromised lower urinary tract function, which was objectively confirmed by abnormal urodynamic studies. In both cases, there was spontaneous improvement in urodynamic parameters, with stable normal urinary function at the long-term follow-up. Although cases of spontaneous radiological regression of SLC have very infrequently been reported, they have not been associated with the reversal of already present neurological deficits. This report reinforces the need for further delineation of the true natural history of SLC and highlights the dynamic nature of associated neurological compromise over time. ( Key Words spinal dysraphism spinal lipoma tethered cord urinary dysfunction urodynamics spine congenital Abbreviations used in this paper: CIC = clean intermittent catheterization; SLC = spinal lipoma of the conus; UDS = urodynamics study. Congenital spinal lipomas of the conus (SLCs) are the most common form of occult spinal dysraphism, accounting for 8% 25% of known spina bifida cases. 1,10,15 There exists substantial controversy and disagreement in the literature concerning the optimal clinical management of these lesions. 16,30,34 In particular, the role of surgical repair in preventing neurological decline in asymptomatic patients has been debated. 12,19,29,34 Furthermore, the value of surgery for static symptomatic SLC remains unclear. 34 These questions stem from a lack of understanding of the natural history of this condition. We report on two male infants with SLC who experienced spontaneous improvement of lower urinary tract dysfunction, providing further insights into the variable natural history of this congenital anomaly. Case 1 Case Reports History and Examination. This male infant presented shortly after birth with a subcutaneous mass and two small overlying cutaneous hemangiomas in the lower lumbar region. The infant appeared to be urinating and defecating without any issues. Neurological examination, including anal tone, was unremarkable apart from an absent ankle jerk reflex in the left leg. Magnetic resonance imaging of the spine demonstrated a low-lying conus medullaris at the L-5 level. A large intraspinal lipoma was 536 J Neurosurg: Pediatrics / Volume 13 / May 2014

2 Urological dysfunction in spinal lipomas seen extending from the L-3 to S-4 levels and communicating with a fatty subcutaneous collection via dysraphic sacral vertebrae (Fig. 1). Urology Assessment. A urodynamics study (UDS) was performed when the boy was 6 months old. He had elevated postvoid residual volumes of ml (reference < 5 ml). 25 In addition, he voided with high pressures in the range of 100 cm H 2 O (reference cm H 2 O). 32 Electromyography revealed incomplete sphincter relaxation. There was also evidence of detrusor overactivity on cystometry. A voiding cystourethrogram demonstrated a dilated posterior urethra; thus, cystoscopy was performed, which ruled out the presence of posterior urethral valves. Serial renal and bladder ultrasounds were unremarkable, without evidence of hydronephrosis or parenchymal abnormality. Given the above evidence of lower urinary tract neurogenic dysfunction, oxybutynin was commenced for high voiding pressures and detrusor instability, and clean intermittent catheterization (CIC) was performed for incomplete bladder emptying. Clinical Course. Surgical intervention was discussed with the patient s parents, but nonoperative management with close clinical follow-up was ultimately chosen. By 11 months of age, the boy s postvoid residual volumes had decreased to approximately 10 ml; therefore, CIC was discontinued. Oxybutynin was stopped soon thereafter, and he has since been urinating spontaneously without any trouble. A repeat UDS when he was 4 years old showed no evidence of urinary dysfunction, and he was completely toilet trained. Follow-up spine MRI performed when the boy was 7 years of age demonstrated a reduction in the size of the intraspinal lipoma, with a persistent low-lying conus medullaris at the L-5 spinal level (Fig. 2). At the last follow-up, this child continued to have normal lower limb strength and sensation, without evidence of bladder or bowel dysfunction after 9 years of serial observation. Fig. 1. Case 1. Sagittal T1-weighted MR images obtained in a 4- month-old infant, demonstrating a spinal lipoma associated with a lowlying conus medullaris at the L-5 spinal level. J Neurosurg: Pediatrics / Volume 13 / May 2014 Fig. 2. Case 1. Sagittal T1-weighted MR images obtained when the boy was 7 years old, revealing an interval decrease in the size of the spinal lipoma and a persistent low-lying conus medullaris at the L-5 spinal level. Case 2 History and Examination. This male infant presented shortly after birth with a skin-covered lumbosacral mass. The child s neurological examination was entirely normal, including lower limb function. Spinal MRI revealed the tip of the conus medullaris was at the level of the L-4 vertebral body. A substantial amount of fat extended from the intradural space of the lumbar and sacral spinal canal, through a posterior 4-mm bony defect at the L5 S1 spinal level, and into a subcutaneous lipomatous collection, consistent with a diagnosis of SLC (Fig. 3). Urology Assessment. When the boy was 2 months of age, a voiding cystourethrogram demonstrated left-sided Grade II vesicoureteral reflux, with retrograde flow of urine into the renal pelvis and calyces. Cystometry revealed uninhibited high-amplitude bladder contractures during filling, with eventual urinary leak through the urethra. Renal and bladder ultrasounds were unremarkable. Additionally, the parents reported frequent urination with small output volumes. Consequently, we started CIC, oxybutynin for detrusor hyperreflexia, and prophylactic antibiotics for vesicoureteral reflux. Clinical Course. Surgical repair of the spinal lipoma was offered on the basis of the clinical signs and abnormal UDS. However, the parents opted for nonoperative treatment. Thus, the boy was managed with serial clinical observation. A UDS at 2 years of age showed persistent overactive bladder with substantial instability, and thus the boy remained on oxybutynin and prophylactic antibiotics. At 4 years of age, he was completely toilet trained and did not have any urinary frequency, urgency, incontinence, or infections. A follow-up evaluation revealed nor- 537

3 J. H. Badhiwala et al. Fig. 3. Case 2. Sagittal T1-weighted MR images obtained in a 5-month-old boy, demonstrating a spinal lipoma with a low-lying conus medullaris at the L-4 spinal level. mal urinary function, with a peak flow rate of 8.8 ml/second, volume voided of 129 ml, and no signs of detrusor instability or detrusor-sphincter dyssynergia. Oxybutynin and antibiotics were eventually discontinued. Follow-up flow-rate studies when the boy was 6 and 8 years old again revealed normal bladder emptying. Routine spinal MRI performed at 10 years of age revealed a persistent low-lying conus at the L-4 level and an interval increase in the size of the known lipoma (Fig. 4). At his 10-year follow-up, the child remained neurologically intact, with no symptoms of urinary dysfunction. Discussion The decision of whether and when to surgically treat SLC remains a topic of heated debate. 12,29,34 Several authors have advocated for prophylactic cord detethering surgery in asymptomatic patients. 2,5,11,12,14,18,22,30,31,33 One purported rationale for this relates to evidence suggesting that once neurological deficits have manifested, only a minority of these patients will improve after surgery, whereas asymptomatic patients only rarely develop symptoms after prophylactic surgery. 5,22,35 There is, however, a paucity of data pertaining to the natural history of SLC and tethered cord. To date, there are only two published series of nonoperatively managed SLC 53 cases from Necker-Enfants Malades Hospital, Paris, 19 and another 56 cases from Great Ormond Street Hospital, London. 34 Both of these natural history studies indicate a more benign clinical course for SLC than previously believed. Neurogenic lower urinary tract dysfunction is considered one of the most frequent manifestations of congenital SLC. 28 Associated clinical symptoms can include urinary incontinence, urinary tract infections, and/or Fig. 4. Case 2. Sagittal T1-weighted MR images obtained when the boy was 10 years of age, revealing an interval increase in the size of the spinal lipoma and a persistent low-lying conus medullaris at the L-4 spinal level. urinary retention. 4,28,30 However, as illustrated by the two cases featured here, children with spinal dysraphism may remain essentially asymptomatic despite the presence of significant urological dysfunction, which speaks to the value, and arguably the necessity, of UDS in evaluating these patients. 6,13,24 Urologists use UDS to detect lower urinary tract dysfunction so that interventions (for example, prophylactic antibiotics, CIC, anticholinergics, and so forth) can be implemented to preserve the integrity of the upper urinary tract (that is, the kidneys). 7 The most important limitation of pediatric UDS occurs when there is a lack of cooperation from the child (for example, irritability, crying, and so forth), which can interfere with abdominal and vesical pressure monitoring. Even then, the reported sensitivity, specificity, positive predictive value, and negative predictive value of UDS in predicting upper urinary tract deterioration in infants with spina bifida can reach 87%, 93%, 85%, and 81%, respectively. 3,21,27 The most common urodynamic findings in the context of congenital SLC include detrusor overactivity, detrusorsphincter dyssynergia, reduced bladder compliance, and incomplete emptying. 9,26 The prognosis of urological dysfunction in spinal dysraphic states is poor in older children and adults, in whom surgery only rarely leads to improvement in symptoms. 30 Satar et al. 30 reported no improvement or worsening of UDS findings in 16 of 19 older patients (mean age 14.5 years) following surgical repair of an occult spinal dysraphism. By contrast, urological outcomes are more favorable in infants, with reversal of bladder deficits not uncommon following cord detethering surgery. 2,16,31 Sathi et al. 31 found normalization of an abnormal preoperative UDS in 83% of infants following operative repair of SLC. Similarly, Atala et al. 2 reported postoperative improvement in lower urinary tract function in 9 of 11 infants with an abnormal preoperative UDS. In any case, the 538 J Neurosurg: Pediatrics / Volume 13 / May 2014

4 Urological dysfunction in spinal lipomas presence of bladder and/or bowel deficits often prompts neurosurgical intervention. 23,29 For this reason, the natural history of urinary dysfunction in the context of SLC has been difficult to ascertain. Here, we report on two male infants with objective evidence of urinary dysfunction, as indicated by abnormal UDS. Both children experienced improvement on long-term close monitoring, with evidence of acceptable bladder dynamics without surgical intervention. These patients had no issues or delays in toilet training and have been clinically followed for 9 and 10 years thus far, while remaining free of lower and upper urinary tract disturbance and symptoms. Although a few cases of spontaneous radiological regression of SLC have been reported, 8,17,20 to our knowledge, spontaneous improvement of abnormal UDS and urinary dysfunction in congenital SLC has not. Based on our observations, it is very possible that the improvement in urinary function associated with early resection of SLC in infancy may actually reflect the natural history of urological dysfunction in this patient population. Our findings highlight the value of serial urological and neurosurgical assessment of children with this condition, as well as the possible role of conservative management as an option in the absence of progressive neurological deficits or upper urinary tract deterioration. Conclusions Our two cases illustrate the possibility of spontaneous reversal of urological dysfunction associated with congenital SLC. These cases reinforce the need for further clarification of the true natural history of SLC. Disclosure The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper. Author contributions to the study and manuscript preparation include the following. Conception and design: Kulkarni, Badhiwala, Thompson. Acquisition of data: Kulkarni, Badhiwala. Analysis and interpretation of data: all authors. Drafting the article: Badhiwala, Thompson. Critically revising the article: all authors. Reviewed submitted version of manuscript: all authors. Approved the final version of the manuscript on behalf of all authors: Kulkarni. Administrative/ technical/material support: Kulkarni. Study supervision: Kulkarni. References 1. Agopian AJ, Canfield MA, Olney RS, Lupo PJ, Ramadhani T, Mitchell LE, et al: Spina bifida subtypes and sub-phenotypes by maternal race/ethnicity in the National Birth Defects Prevention Study. Am J Med Genet A 158A: , Atala A, Bauer SB, Dyro FM, Shefner J, Shillito J, Sathi S, et al: Bladder functional changes resulting from lipomyelomeningocele repair. J Urol 148: , Bauer SB, Hallett M, Khoshbin S, Lebowitz RL, Winston KR, Gibson S, et al: Predictive value of urodynamic evaluation in newborns with myelodysplasia. 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5 J. H. Badhiwala et al. studies in infants less than 1 year old with congenital spinal dysraphism. J Urol 148: , Pierre-Kahn A, Zerah M, Renier D, Cinalli G, Sainte-Rose C, Lellouch-Tubiana A, et al: Congenital lumbosacral lipomas. Childs Nerv Syst 13: , Sarris CE, Tomei KL, Carmel PW, Gandhi CD: Lipomyelomeningocele: pathology, treatment, and outcomes. A review. Neurosurg Focus 33(4):E3, Satar N, Bauer SB, Shefner J, Kelly MD, Darbey MM: The effects of delayed diagnosis and treatment in patients with an occult spinal dysraphism. J Urol 154: , Sathi S, Madsen JR, Bauer S, Scott RM: Effect of surgical repair on the neurologic function in infants with lipomeningocele. Pediatr Neurosurg 19: , Wen JG, Tong EC: Cystometry in infants and children with no apparent voiding symptoms. Br J Urol 81: , Wu HY, Kogan BA, Baskin LS, Edwards MS: Long-term benefits of early neurosurgery for lipomyelomeningocele. J Urol 160: , Wykes V, Desai D, Thompson DN: Asymptomatic lumbosacral lipomas a natural history study. Childs Nerv Syst 28: , Xenos C, Sgouros S, Walsh R, Hockley A: Spinal lipomas in children. Pediatr Neurosurg 32: , 2000 Manuscript submitted October 6, Accepted February 24, Please include this information when citing this paper: published online March 28, 2014; DOI: / PEDS Address correspondence to: Abhaya V. Kulkarni, M.D., Ph.D., Division of Neurosurgery, The Hospital for Sick Children, 555 University Ave., Rm. 1503, Toronto, ON M5G 1X8, Canada. abhaya.kulkarni@sickkids.ca. 540 J Neurosurg: Pediatrics / Volume 13 / May 2014