Closed spinal dysraphism

Letters to the Editor been symptom-free until the age of 3% years, when she completely lost the ability to walk and was only able to stand with support. She regained ambulation postoperatively and subsequently returned to completely normal motor function. Urinary tract involvement was also common with evidence of infection in eight of the patients, with four having associated hydronephrosis on intravenous pyelography. That was of course before the remarkable advances in imaging over the ensuing decades. The question was raised at that time as to whether prophylactic surgical intervention was justified in asymptomatic children with a lipoma of the cauda equina. I am not sure whether that has yet been fully answered. Yours faithfully, Victor

Dubowitz

Department of Paediatrics, Hanznzersnzith Hospital, Imperial College School of Medicine, Du Cane Road, London WI2 ONN, UK Ew j Pndintr

Newel

1998; 2: 324-325

Reference 1

Dubowitz V, Lorber J, Zachary RB. Lipoma of the cauda equina. Arch Dis CMdh 1965; 40: 207-213.

Sir, We are much indebted for the additional comments by Professor Dubowitzr on our review regarding closed spinal dysraphism.2 His major concern relates to the debate on whether a recommendation of prophylactic tethered cord release in asymptomatic closed spinal dysraphic patients is presently still justified. Because of impressive advances in imaging and other diagnostic techniques over the past decades, several old discussions within the field of child neurology currently need to be resumed. More specifically, new techniques now enable the confirmation of covert abnormalities before overt clinical deterioration occurs. Urinary tract symptoms comprise a broad spectrum of severity, from subtle abnormalities only detectable with urodynamic investigation until severe end-stage renal failure. As described in the Dubowitz study, the four patients with evidence of hydronephrosis must

325 have suffered an upper motor neuron disease for a while, causing a continuous hyperactivity of’ the detrusor against a non-relaxing external sphincter (bladder-external sphincter dyssynergy).3 This can result in a sequence of high bladder emptying pressures, functional urinary obstruction with insufficient bladder emptying, urinary tract infections, vesicoureteral reflux, with ultimately hydronephrosis and renal failure. Our actual goal is that of careful surveillance by a multidisciplinary medical team, together with a correct use of diagnostic techniques in order to detect abnormal upper or lower motor neuron signs.during their covert phase. Over the last decade, several groups have reported on closed spinal dysraphism and tethered cord. The use of new diagnostic tools together with a close clinical follow-up of these patients resulted in a more solid understanding of the pathophysiological mechanisms causing this disease entity. In that sense, the discussion concerning the topic of early prophylactic surgical intervention in closed spinal dysraphism, raised in the early 196Os, should be reopened. In contrast to earlier publications, defending the philosophy of prophylactic surgery, a growing body of evidence indicates that such an attitude to these patients is hard to justify. However, currently available evidence is mainly based on several isolated anecdotal reports of patients with tethered cord, going from childhood into adulthood without developing any dysfunction. PierreKahn et al. (1977) were the first to do an objective analysis of 291 lipomas operated on from 1972 to 1994, with a postoperative follow-up in 93 patients of more than 5 years. 4 This exhaustive study questions the rationale for prophylactic surgery, since untethering of the spinal cord and debulking of lipomas of the conus in these patients failed to prevent the onset of late neurological deficits in almost half of them. Most other studies are often difficult to interpret due to potentially confounding factors, e.g. category of primary lesion, severity and duration of symptoms, age and previous surgery. The cohort in Leuven is a more homogeneous group of closed spinal dysraphic patients without such interfering factors. Although we do confirm the hypothesis that surgical untethering is indicated only upon presentation of upper motor neuron disease in these patients, our results still need to be confirmed by other groups. Two prerequisites needed to conclude the debate of prophylactic untethering are (i) a further subdivision of closed spinal dysraphic patients into homogeneous patient groups5 and (ii) prospectively designed studies that only include patients regularly followed up since birth.

Letters to the Editor

326

Once more we thank Professor Dubowitz for his comments and look forward to hearing the experience of other colleagues and centres. Yours

faithfully,

V. Newel

Closed spinal dysraphism. 1998; 2: 324-325.

(Letter)

Dubowitz V, Lorber J, Zachary R. Lipoma equina. Arch Dis Child/i 1965; 40: 207-213.

Department of Paediatrics-Child Neurology, University Hospital Gasthuisberg, 3000 Leuven, Belgium Neural

Dubowitz Pnedialr

Ew

\

Comette L, Verpoorten C, Lagae L et al. Closed spinal dysraphism: a review on diagnosis and treatment in infancy. Ew j Pnediafr Neural 1998; 2: 179-185.

Luc Comette, Carla Verpoorten, Paul Casaer

Ew ] Pnedinh

References

1998; 2: 325-326

Pierre-Kahn lumbosacral

of the cauda

A, Zerah M, Renier D et al. Congenital lipomas. Childs Nerv Syst 1997; 13: 298-335.

Liptak S. Tethered published articles. 21-23.

spinal cord: update Eur ] Pedintr Swg

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