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Early clinical signs and symptoms in occult spinal dysraphism: a retrospective case study of 47 patients
Clinical Neurology and Neurosurgery 101 (1999) 11 – 14
Early clinical signs and symptoms in occult spinal dysraphism: a retrospective case study of 47 patients N. Soonawala a, W.C.G. Overweg-Plandsoen b, O.F. Brouwer a,* a b
Department of Neurology, Leiden Uni6ersity Medical Centre, P.O. Box 9600, 2300 RC Leiden, The Netherlands Department of Child Neurology, Academic Medical Centre, Uni6ersity of Amsterdam, Amsterdam, The Netherlands Received 15 April 1998; received in revised form 13 August 1998; accepted 30 October 1998
Abstract Since occult spinal dysraphism can lead to irreversible neurological complications, early diagnosis and treatment are necessary. We retrospectively studied the presenting clinical signs and symptoms in all 47 cases of occult spinal dysraphism identified in two university hospitals in The Netherlands since 1965. Dermal sinus had been diagnosed in 12, lipomyelomeningocele in nine, and diastematomyelia in eight patients. Thirty-three patients had symptoms due to tethering of the spinal cord, leading to a clinical suspicion of occult spinal dysraphism in only eight cases. Twenty-eight patients had cutaneous back lesions that led to further investigation in eight cases. Nineteen patients had a small backmass leading to further examination in 13 cases. Three patients with dermal sinus presented with meningitis caused by an unusual aetiological agent. This study stresses the importance of identification of neurological dysfunction due to tethered cord syndrome, cutaneous back lesions, a small backmass and meningitis caused by an unusual aetiological agent for the early diagnosis of occult spinal dysraphism. © 1999 Elsevier Science B.V. All rights reserved. Keywords: Diagnosis; Occult spinal dysraphism
1. Introduction Spinal dysraphism encompasses a wide spectrum of congenital anomalies united by an abnormality of fusion of one or all of the midline mesenchymal, bony and neural elements of the spine. Spina bifida aperta is characterized by a dorsal herniation of all or part of the spinal contents and includes meningocele and myelomeningocele. In spina bifida occulta the skin overlying the spinal anomaly is intact, no neural tissue is exposed and no obvious mass is present. Included in this group are dorsal dermal sinus, diastematomyelia, caudal regression syndrome, tight filum terminale syndrome, intradural lipoma, syringohydromyelia, anterior sacral meningocele and split notochord syndrome [1]. Prob* Corresponding author. Tel.: + 31-71-5262134; fax: 5248253.
+ 31-71-
lems arise when one tries to classify the lipomyelomeningocele and certain cases of meningocele in which the lesions are skin-covered and the backmass is small. Some classify these as occulta and others as aperta. Byrd et al. [2] resolved the issue by dividing spinal dysraphism into three categories: spinal dysraphism with a non-covered backmass (spina bifida aperta), spinal dysraphism with a skin-covered backmass (spina bifida cystica) and spinal dysraphism without backmass (occult spinal dysraphism). Spina bifida occulta has for a long time been regarded as a minor defect in the development of the vertebral laminae and spinous processes. However, the condition can be associated with congenital anomalies of the spinal cord and cauda equina [3]. It would be more appropriate to use the term occult spinal dysraphism when referring to the condition in which spina bifida occulta is associated with congenital anomalies of the spinal cord. Occult
0303-8467/99/$ - see front matter © 1999 Elsevier Science B.V. All rights reserved. PII: S 0 3 0 3 - 8 4 6 7 ( 9 8 ) 0 0 0 7 3 - 0
N. Soonawala et al. / Clinical Neurology and Neurosurgery 101 (1999) 11–14
12
Table 1 Different types of occult spinal dysraphism in 47 patients and the main presenting sign or symptom. Type of occult spinal dysraphism
Number of patients
Dermal sinus
12
Lipomyelomeningocele
M/F
Age at diagnosis (years, mean 9 S.D.)
Main presenting sign or symptom (number of patients)
4/8
0.8 9 1.0
9
5/4
0.3 9 0.4
Diastematomyelia
8
3/5
2.5 93.1
Meningocele
5
2/3
1.291.7
Caudal regression syndrome
5
2/3
2.6 93.3
Lumbosacral dimples (6) Meningitis (3)a Sacral hyperpigmentation and haemangioma (1) Sudden urine retention (1) Gait disturbance (1) Backmass (4) Backmass and associated cutaneous lesions (4) Equinovarus deformity of feet (1) Scoliosis (3) Leg length discrepancy (3) Eversion of the feet (1) Planovalgus deformity of both feet (1) Small backmass (4) Chronic urinary tract infections (1) Foot deformities and incontinentia urinae (3)
Intradural lipoma
3
2/1
3.5 94.6
Tight filum terminale Dermal tumour Undefined
1 1 3
0/1 0/1 1/2
2.4 5.6 7.7 95.6
47
19/28
2.0 91.9
Total a
Foot deformities (1) Dimple (1) Small backmass (1) Incontinentia urinae (1) Bladder and bowel dysfunction (1) Spastic paresis of lower extremities (1) Sudden backpain and paraparesis (1) Foot deformities (2) Various congenital defects at birth (1) Incontinentia urinae (1)
Klebsiella peumoniae, Staphylococcus epidermidis, Escherichia coli.
spinal dysraphism may be associated with a clinical syndrome which is often referred to as the tethered cord syndrome, denoting an abnormal fixation of the spinal cord. Since the most common location for the spinal cord to be tethered is its distal aspect or conus, these patients may present symptoms of motor and sensory loss in the lower extremities and bowel and bladder dysfunction. In this study, specific attention was paid to the problems surrounding the early detection of occult spinal dysraphism. It needs to be detected at an early stage before the inception of a progressive neurological deficit which is often irreversible despite surgical intervention. To prevent future disability, prophylactic surgery to untether the conus and decompress any mass effect is recommended at an early stage [4]. By studying the presenting clinical signs and symptoms, the early diagnosis of occult spinal dysraphism was addressed.
2. Methods All 47 cases of occult spinal dysraphism observed between 1965 and 1996 in two university hospitals in
The Netherlands were reviewed. Patients were selected on the basis of a definition of occult spinal dysraphism based on radiological findings and physical examination, including disputable skin-covered lesions such as lipomyelomeningoceles and small meningoceles. Nineteen cases originated from the Leiden University Medical Centre and 28 cases from the Academic Medical Centre in Amsterdam. Clinical, radiological and surgical notes were studied. Reports of the imaging studies were examined and not the actual images. The details were systematically stored in the database program Dbase IV.
3. Results The 47 cases studied included 19 male and 28 female patients, ranging in age at diagnosis from the postnatal period to 14 years, with a mean age of 2.0 years. The observed types of occult dysraphic pathology and the main presenting signs and symptoms that led to a clinical suspicion of occult spinal dysraphism are shown in Table 1. Assignment of the patients to a particular group was made to emphasize the predominant lesion observed. In three cases the lesions could
N. Soonawala et al. / Clinical Neurology and Neurosurgery 101 (1999) 11–14 Table 2 Clinical findings in 47 patients with occult spinal dysraphisma Clinical findings
Number of patients
Dermatological Dimple Hypertrichosis Naevi Hyper/hypopigmentation Haemangioma
28 17 13 5 5 4
Small backmass
19
Tethered cord syndrome Neurological symptoms Motor and sensory loss lower extremities Motor loss lower extremities Abnormalities in knee jerk reflex/ankle jerk reflex/plantar response Sensory loss lower extremities Urological symptoms Incontinentia urinae Urine retention Urinary tract infections Orthopaedic symptoms Foot deformities Scoliosis Leg length discrepancy Kyphosis
33 11 11 6 2 5 1 1 12 6 5 1
a The number of specified symptoms exceeds the total number of patients with such symptoms since several patients had a combination of symptoms.
not be defined properly. No cases of syringohydromyelia, split notochord syndrome or anterior sacral meningocele were identified. When initial signs and symptoms led to further examination, a variety of dermatological, neurological, urological and orthopaedic symptoms was encountered as shown in Table 2. In 23 cases, initial clinical suspicion was based upon symptoms due to tethering of the spinal cord. However, such symptoms were found in 33 patients. Cutaneous lesions were the initial sign leading to a clinical suspicion of occult spinal dysraphism in eight cases, while these lesions were found in 28 cases. Ten of these patients had a combination of two or more cutaneous lesions. In 13 of 19 patients with a small backmass, this was the reason for further investigation. In our study group of 47 patients, plain radiography had been performed in 42 cases, magnetic resonance imaging (MRI) in 33, myelography in eight, computed tomographic (CT) scan in five, CT – myelography in two and sonography in three cases. A diagnosis of occult spinal dysraphism was made by one or more of these radiological studies.
13
4. Discussion In this study 47 cases of occult spinal dysraphism were reviewed. Although the marked female preponderance as was observed (28 female and 19 male patients) has been acknowledged by various researchers, it remains unexplained [5]. The prevalence of occult spinal dysraphism has been estimated at 0.05/1000 in The Netherlands, but the prevalence of the different types of occult spinal dysraphism has not been specified. The integumentary and nervous systems are related by a common ectodermal origin, so that midline cutaneous lesions may indicate malformations of the spinal cord and associated structures. The skin lesions associated with spinal abnormalities include hypertrichosis, dimples, lipoma, angioma and naevi [6,7]. Twenty-eight patients in this study had cutaneous lesions. In only eight cases did these lesions themselves lead to a clinical suspicion of spinal dysraphism. Most of the lesions found consisted of a dimple or a hairy patch. James and Lassman mentioned an association between hypertrichosis and diastematomyelia [3]. Apart from a dimple being associated with dermal sinus, none of the observed surface abnormalities in this study was related to a particular type of spinal dysraphism. It is important to recognize the significance of a pit in a midline ‘birthmark’ since a dermal sinus tract often presents as a dimple in the skin. Although all the studied patients with dermal sinus had a dimple and/or associated cutaneous manifestations, it was only in seven cases that these signs led to a suspicion of occult spinal dysraphism. It is often difficult to decide whether a deep dimple is a sinus or whether a shallow sinus is a dimple. Their importance relates to their potential for becoming infected and leading to meningitis. When a dermal dimple on the lumbar or sacral area is associated with recurrent meningitis or neurological dysfunction it should be assumed that there is an intraspinal extension of a dermal sinus tract [8,9]. Three patients with dermal sinus in this study presented with meningitis caused by an unusual aetiological agent. The clinical spectrum of tethered cord syndrome includes pain, sensorimotor defects of the lower extremities, bladder and bowel dysfunction, leg atrophy and scoliosis. In this study in 23 cases the initial presenting symptoms were due to tethering of the spinal cord. However, after further examination, 33 of the 47 patients were found to have such symptoms. A skin-covered backmass could indicate the presence of a lipomyelomeningocele, intradural lipoma or meningocele. In this study a small backmass was present in 19 of the 47 cases and led to a clinical suspicion in 13 patients. In this study the radiological reports were reviewed and not the actual images. Furthermore, as this study is based on patients observed between 1965 and 1996, CT
14
N. Soonawala et al. / Clinical Neurology and Neurosurgery 101 (1999) 11–14
was not introduced until 1978 and MRI not until the late 1980s. Nowadays, under the age of 3 months, ultrasonography of the spinal canal is the investigation of first choice in an asymptomatic infant having only a cutaneous stigma located at the lumbosacral level [10–13]. At that age the posterior bony fusion of the vertebral arches, which normally is completed at 1 year, has not yet taken place. If ultrasonography is abnormal or if there is a clinical suspicion of a dysraphic malformation, MRI of the spine is indicated [14 – 17]. In conclusion, patients with occult spinal dysraphism may present a variety of symptoms. It is important to recognize early clinical signs such as symptoms due to tethering of the spinal cord, cutaneous lesions, a small backmass and meningitis with an unusual aetiological agent. Timely and adequate radiological work-up should then be performed.
Acknowledgements We thank Dr M.A. van Buchem for helpful comments on the radiological aspects of this work.
References [1] Tortori-Donati P, Cama A, Rosa ML, Andreussi L, Taccona A. Occult spinal dysraphism: neuroradiological study. Neuroradiology 1990;31:512 – 22. [2] Byrd SE, Darling CF, McLone DG. Developmental disorders of the pediatric spine. Radiol Clin North Am 1991;29:711– 52. [3] James MJ, Lassman LP. Spina Bifida Occulta: Orthopaedic Radiological and Neurosurgical Aspects. London: Academic Press, 1981.
.
[4] Satar N, Bauer SB, Shefner J, Kelly MD, Darbey MM. The effect of delayed diagnosis and treatment in patients with an occult spinal dysraphism. J Urol 1995;154:754 – 8. [5] Elwood JM, Elwood JH. Epidemiology of Anencephalus and Spina Bifida. Oxford: Oxford University Press, 1980. [6] Davis DA, Cohen PR, George RE. Cutaneous stigmata of occult spinal dysraphism. J Am Acad Dermatol 1994;31:892 –6. [7] Serna MJ, Va´zquez-Doval J, Vanaclocha V, Zubieta JL, Quintanilla E. Occult spinal dysraphism: a neurosurgical problem with a dermatological hallmark. Pediatr Dermatol 1993;10:149– 52. [8] Borowsky AD, Stein SM, Tulipan NB, Dermody TS. Meningitis caused by mixed anaerobic species complicating tethered cord syndrome (letter). Clin Infect Dis 1995;21:706 – 7. [9] Gurbani SG, Cho CT, Lee KR. Staphylococcus epidermidis meningitis and an intraspinal abscess associated with a midthoracic dermal sinus tract. Clin Infect Dis 1994;19:1138 –40. [10] Anderson NG, Jordan S, MacFarlane MR, Lovell-Smith M. Diastematomyelia: diagnosis by prenatal sonography. Am J Radiol 1994;163:911 – 4. [11] Beek FJA. Ultrasound of the lower spinal canal in infants. Thesis, Medical Faculty, University of Utrecht, Utrecht, 1995. [12] Korsvik HE, Keller MS. Sonography of occult dysraphism in infants with MR imaging correlation. Radiographics 1992;12:297 – 306. [13] Sepulveda W, Kyle PM, Hassan J, Weiner E. Prenatal diagnosis of diastematomyelia: case reports and review of the literature. Prenatal Diagn 1997;17:161 – 5. [14] Davis PC, Hoffman Jr JC, Ball TI, Wyly JB, Braun IF, Fry SM, Drvaric DM. Spinal abnormalities in pediatric patients: MR imaging findings compared with clinical, myelographic, and surgical findings. Radiology 1988;166:679 – 85. [15] Wippold FJ, Citrin C, Barkovich AJ, Sherman JS. Evaluation of MR in spinal dysraphism with lipoma: comparison with metrizamide computed computer tomography. Pediatr Radiol 1987;17:184 – 8. [16] Barkovich AJ, Edwards MSB, Cogen PH. MR evaluation of spinal dermal sinus tracts in children. Am J Neuroradiol 1991;12:123 – 9. [17] Cornette L, Verpoorten C, Lagae L, Plets C, van Calenbergh F, Casaer P. Closed spinal dysraphism: a review on diagnosis and treatment in infancy. Eur J Pediatr Neurol 1998;2:179 –85.
Early clinical signs and symptoms in occult spinal dysraphism: a retrospective case study of 47 patients N. Soonawala a, W.C.G. Overweg-Plandsoen b, O.F. Brouwer a,* a b
Department of Neurology, Leiden Uni6ersity Medical Centre, P.O. Box 9600, 2300 RC Leiden, The Netherlands Department of Child Neurology, Academic Medical Centre, Uni6ersity of Amsterdam, Amsterdam, The Netherlands Received 15 April 1998; received in revised form 13 August 1998; accepted 30 October 1998
Abstract Since occult spinal dysraphism can lead to irreversible neurological complications, early diagnosis and treatment are necessary. We retrospectively studied the presenting clinical signs and symptoms in all 47 cases of occult spinal dysraphism identified in two university hospitals in The Netherlands since 1965. Dermal sinus had been diagnosed in 12, lipomyelomeningocele in nine, and diastematomyelia in eight patients. Thirty-three patients had symptoms due to tethering of the spinal cord, leading to a clinical suspicion of occult spinal dysraphism in only eight cases. Twenty-eight patients had cutaneous back lesions that led to further investigation in eight cases. Nineteen patients had a small backmass leading to further examination in 13 cases. Three patients with dermal sinus presented with meningitis caused by an unusual aetiological agent. This study stresses the importance of identification of neurological dysfunction due to tethered cord syndrome, cutaneous back lesions, a small backmass and meningitis caused by an unusual aetiological agent for the early diagnosis of occult spinal dysraphism. © 1999 Elsevier Science B.V. All rights reserved. Keywords: Diagnosis; Occult spinal dysraphism
1. Introduction Spinal dysraphism encompasses a wide spectrum of congenital anomalies united by an abnormality of fusion of one or all of the midline mesenchymal, bony and neural elements of the spine. Spina bifida aperta is characterized by a dorsal herniation of all or part of the spinal contents and includes meningocele and myelomeningocele. In spina bifida occulta the skin overlying the spinal anomaly is intact, no neural tissue is exposed and no obvious mass is present. Included in this group are dorsal dermal sinus, diastematomyelia, caudal regression syndrome, tight filum terminale syndrome, intradural lipoma, syringohydromyelia, anterior sacral meningocele and split notochord syndrome [1]. Prob* Corresponding author. Tel.: + 31-71-5262134; fax: 5248253.
+ 31-71-
lems arise when one tries to classify the lipomyelomeningocele and certain cases of meningocele in which the lesions are skin-covered and the backmass is small. Some classify these as occulta and others as aperta. Byrd et al. [2] resolved the issue by dividing spinal dysraphism into three categories: spinal dysraphism with a non-covered backmass (spina bifida aperta), spinal dysraphism with a skin-covered backmass (spina bifida cystica) and spinal dysraphism without backmass (occult spinal dysraphism). Spina bifida occulta has for a long time been regarded as a minor defect in the development of the vertebral laminae and spinous processes. However, the condition can be associated with congenital anomalies of the spinal cord and cauda equina [3]. It would be more appropriate to use the term occult spinal dysraphism when referring to the condition in which spina bifida occulta is associated with congenital anomalies of the spinal cord. Occult
0303-8467/99/$ - see front matter © 1999 Elsevier Science B.V. All rights reserved. PII: S 0 3 0 3 - 8 4 6 7 ( 9 8 ) 0 0 0 7 3 - 0
N. Soonawala et al. / Clinical Neurology and Neurosurgery 101 (1999) 11–14
12
Table 1 Different types of occult spinal dysraphism in 47 patients and the main presenting sign or symptom. Type of occult spinal dysraphism
Number of patients
Dermal sinus
12
Lipomyelomeningocele
M/F
Age at diagnosis (years, mean 9 S.D.)
Main presenting sign or symptom (number of patients)
4/8
0.8 9 1.0
9
5/4
0.3 9 0.4
Diastematomyelia
8
3/5
2.5 93.1
Meningocele
5
2/3
1.291.7
Caudal regression syndrome
5
2/3
2.6 93.3
Lumbosacral dimples (6) Meningitis (3)a Sacral hyperpigmentation and haemangioma (1) Sudden urine retention (1) Gait disturbance (1) Backmass (4) Backmass and associated cutaneous lesions (4) Equinovarus deformity of feet (1) Scoliosis (3) Leg length discrepancy (3) Eversion of the feet (1) Planovalgus deformity of both feet (1) Small backmass (4) Chronic urinary tract infections (1) Foot deformities and incontinentia urinae (3)
Intradural lipoma
3
2/1
3.5 94.6
Tight filum terminale Dermal tumour Undefined
1 1 3
0/1 0/1 1/2
2.4 5.6 7.7 95.6
47
19/28
2.0 91.9
Total a
Foot deformities (1) Dimple (1) Small backmass (1) Incontinentia urinae (1) Bladder and bowel dysfunction (1) Spastic paresis of lower extremities (1) Sudden backpain and paraparesis (1) Foot deformities (2) Various congenital defects at birth (1) Incontinentia urinae (1)
Klebsiella peumoniae, Staphylococcus epidermidis, Escherichia coli.
spinal dysraphism may be associated with a clinical syndrome which is often referred to as the tethered cord syndrome, denoting an abnormal fixation of the spinal cord. Since the most common location for the spinal cord to be tethered is its distal aspect or conus, these patients may present symptoms of motor and sensory loss in the lower extremities and bowel and bladder dysfunction. In this study, specific attention was paid to the problems surrounding the early detection of occult spinal dysraphism. It needs to be detected at an early stage before the inception of a progressive neurological deficit which is often irreversible despite surgical intervention. To prevent future disability, prophylactic surgery to untether the conus and decompress any mass effect is recommended at an early stage [4]. By studying the presenting clinical signs and symptoms, the early diagnosis of occult spinal dysraphism was addressed.
2. Methods All 47 cases of occult spinal dysraphism observed between 1965 and 1996 in two university hospitals in
The Netherlands were reviewed. Patients were selected on the basis of a definition of occult spinal dysraphism based on radiological findings and physical examination, including disputable skin-covered lesions such as lipomyelomeningoceles and small meningoceles. Nineteen cases originated from the Leiden University Medical Centre and 28 cases from the Academic Medical Centre in Amsterdam. Clinical, radiological and surgical notes were studied. Reports of the imaging studies were examined and not the actual images. The details were systematically stored in the database program Dbase IV.
3. Results The 47 cases studied included 19 male and 28 female patients, ranging in age at diagnosis from the postnatal period to 14 years, with a mean age of 2.0 years. The observed types of occult dysraphic pathology and the main presenting signs and symptoms that led to a clinical suspicion of occult spinal dysraphism are shown in Table 1. Assignment of the patients to a particular group was made to emphasize the predominant lesion observed. In three cases the lesions could
N. Soonawala et al. / Clinical Neurology and Neurosurgery 101 (1999) 11–14 Table 2 Clinical findings in 47 patients with occult spinal dysraphisma Clinical findings
Number of patients
Dermatological Dimple Hypertrichosis Naevi Hyper/hypopigmentation Haemangioma
28 17 13 5 5 4
Small backmass
19
Tethered cord syndrome Neurological symptoms Motor and sensory loss lower extremities Motor loss lower extremities Abnormalities in knee jerk reflex/ankle jerk reflex/plantar response Sensory loss lower extremities Urological symptoms Incontinentia urinae Urine retention Urinary tract infections Orthopaedic symptoms Foot deformities Scoliosis Leg length discrepancy Kyphosis
33 11 11 6 2 5 1 1 12 6 5 1
a The number of specified symptoms exceeds the total number of patients with such symptoms since several patients had a combination of symptoms.
not be defined properly. No cases of syringohydromyelia, split notochord syndrome or anterior sacral meningocele were identified. When initial signs and symptoms led to further examination, a variety of dermatological, neurological, urological and orthopaedic symptoms was encountered as shown in Table 2. In 23 cases, initial clinical suspicion was based upon symptoms due to tethering of the spinal cord. However, such symptoms were found in 33 patients. Cutaneous lesions were the initial sign leading to a clinical suspicion of occult spinal dysraphism in eight cases, while these lesions were found in 28 cases. Ten of these patients had a combination of two or more cutaneous lesions. In 13 of 19 patients with a small backmass, this was the reason for further investigation. In our study group of 47 patients, plain radiography had been performed in 42 cases, magnetic resonance imaging (MRI) in 33, myelography in eight, computed tomographic (CT) scan in five, CT – myelography in two and sonography in three cases. A diagnosis of occult spinal dysraphism was made by one or more of these radiological studies.
13
4. Discussion In this study 47 cases of occult spinal dysraphism were reviewed. Although the marked female preponderance as was observed (28 female and 19 male patients) has been acknowledged by various researchers, it remains unexplained [5]. The prevalence of occult spinal dysraphism has been estimated at 0.05/1000 in The Netherlands, but the prevalence of the different types of occult spinal dysraphism has not been specified. The integumentary and nervous systems are related by a common ectodermal origin, so that midline cutaneous lesions may indicate malformations of the spinal cord and associated structures. The skin lesions associated with spinal abnormalities include hypertrichosis, dimples, lipoma, angioma and naevi [6,7]. Twenty-eight patients in this study had cutaneous lesions. In only eight cases did these lesions themselves lead to a clinical suspicion of spinal dysraphism. Most of the lesions found consisted of a dimple or a hairy patch. James and Lassman mentioned an association between hypertrichosis and diastematomyelia [3]. Apart from a dimple being associated with dermal sinus, none of the observed surface abnormalities in this study was related to a particular type of spinal dysraphism. It is important to recognize the significance of a pit in a midline ‘birthmark’ since a dermal sinus tract often presents as a dimple in the skin. Although all the studied patients with dermal sinus had a dimple and/or associated cutaneous manifestations, it was only in seven cases that these signs led to a suspicion of occult spinal dysraphism. It is often difficult to decide whether a deep dimple is a sinus or whether a shallow sinus is a dimple. Their importance relates to their potential for becoming infected and leading to meningitis. When a dermal dimple on the lumbar or sacral area is associated with recurrent meningitis or neurological dysfunction it should be assumed that there is an intraspinal extension of a dermal sinus tract [8,9]. Three patients with dermal sinus in this study presented with meningitis caused by an unusual aetiological agent. The clinical spectrum of tethered cord syndrome includes pain, sensorimotor defects of the lower extremities, bladder and bowel dysfunction, leg atrophy and scoliosis. In this study in 23 cases the initial presenting symptoms were due to tethering of the spinal cord. However, after further examination, 33 of the 47 patients were found to have such symptoms. A skin-covered backmass could indicate the presence of a lipomyelomeningocele, intradural lipoma or meningocele. In this study a small backmass was present in 19 of the 47 cases and led to a clinical suspicion in 13 patients. In this study the radiological reports were reviewed and not the actual images. Furthermore, as this study is based on patients observed between 1965 and 1996, CT
14
N. Soonawala et al. / Clinical Neurology and Neurosurgery 101 (1999) 11–14
was not introduced until 1978 and MRI not until the late 1980s. Nowadays, under the age of 3 months, ultrasonography of the spinal canal is the investigation of first choice in an asymptomatic infant having only a cutaneous stigma located at the lumbosacral level [10–13]. At that age the posterior bony fusion of the vertebral arches, which normally is completed at 1 year, has not yet taken place. If ultrasonography is abnormal or if there is a clinical suspicion of a dysraphic malformation, MRI of the spine is indicated [14 – 17]. In conclusion, patients with occult spinal dysraphism may present a variety of symptoms. It is important to recognize early clinical signs such as symptoms due to tethering of the spinal cord, cutaneous lesions, a small backmass and meningitis with an unusual aetiological agent. Timely and adequate radiological work-up should then be performed.
Acknowledgements We thank Dr M.A. van Buchem for helpful comments on the radiological aspects of this work.
References [1] Tortori-Donati P, Cama A, Rosa ML, Andreussi L, Taccona A. Occult spinal dysraphism: neuroradiological study. Neuroradiology 1990;31:512 – 22. [2] Byrd SE, Darling CF, McLone DG. Developmental disorders of the pediatric spine. Radiol Clin North Am 1991;29:711– 52. [3] James MJ, Lassman LP. Spina Bifida Occulta: Orthopaedic Radiological and Neurosurgical Aspects. London: Academic Press, 1981.
.
[4] Satar N, Bauer SB, Shefner J, Kelly MD, Darbey MM. The effect of delayed diagnosis and treatment in patients with an occult spinal dysraphism. J Urol 1995;154:754 – 8. [5] Elwood JM, Elwood JH. Epidemiology of Anencephalus and Spina Bifida. Oxford: Oxford University Press, 1980. [6] Davis DA, Cohen PR, George RE. Cutaneous stigmata of occult spinal dysraphism. J Am Acad Dermatol 1994;31:892 –6. [7] Serna MJ, Va´zquez-Doval J, Vanaclocha V, Zubieta JL, Quintanilla E. Occult spinal dysraphism: a neurosurgical problem with a dermatological hallmark. Pediatr Dermatol 1993;10:149– 52. [8] Borowsky AD, Stein SM, Tulipan NB, Dermody TS. Meningitis caused by mixed anaerobic species complicating tethered cord syndrome (letter). Clin Infect Dis 1995;21:706 – 7. [9] Gurbani SG, Cho CT, Lee KR. Staphylococcus epidermidis meningitis and an intraspinal abscess associated with a midthoracic dermal sinus tract. Clin Infect Dis 1994;19:1138 –40. [10] Anderson NG, Jordan S, MacFarlane MR, Lovell-Smith M. Diastematomyelia: diagnosis by prenatal sonography. Am J Radiol 1994;163:911 – 4. [11] Beek FJA. Ultrasound of the lower spinal canal in infants. Thesis, Medical Faculty, University of Utrecht, Utrecht, 1995. [12] Korsvik HE, Keller MS. Sonography of occult dysraphism in infants with MR imaging correlation. Radiographics 1992;12:297 – 306. [13] Sepulveda W, Kyle PM, Hassan J, Weiner E. Prenatal diagnosis of diastematomyelia: case reports and review of the literature. Prenatal Diagn 1997;17:161 – 5. [14] Davis PC, Hoffman Jr JC, Ball TI, Wyly JB, Braun IF, Fry SM, Drvaric DM. Spinal abnormalities in pediatric patients: MR imaging findings compared with clinical, myelographic, and surgical findings. Radiology 1988;166:679 – 85. [15] Wippold FJ, Citrin C, Barkovich AJ, Sherman JS. Evaluation of MR in spinal dysraphism with lipoma: comparison with metrizamide computed computer tomography. Pediatr Radiol 1987;17:184 – 8. [16] Barkovich AJ, Edwards MSB, Cogen PH. MR evaluation of spinal dermal sinus tracts in children. Am J Neuroradiol 1991;12:123 – 9. [17] Cornette L, Verpoorten C, Lagae L, Plets C, van Calenbergh F, Casaer P. Closed spinal dysraphism: a review on diagnosis and treatment in infancy. Eur J Pediatr Neurol 1998;2:179 –85.