Tethered cord syndrome versus low-placed conus medullaris in an over-distended spinal cord following initial repair for myelodysplasia

Retethering after transection of a tight filum terminale, postoperative MRI may help to identify patients at risk

PURPOSE

Retethering after transection of a tight filum terminale (TFT) deemed to be a rare and usually only years after initial surgery occurring complication. Possible perioperative factors that might influence the retethering rate or help to allow a prognostic risk assessment are still poorly investigated. The aim of this study was to analyze our patient cohort who underwent a TFT transection by assessing clinical outcome, retethering rate, and pre- and postoperative MRI studies.

METHODS

All consecutive patients undergoing transection of a TFT from January 2011 to December 2018 were evaluated. Inclusion criteria were defined as exclusive TFT intervention and a minimum follow up period of 1 year. Epidemiological data, treatment modalities, complication characteristics, and MRI studies were recorded and analyzed.

RESULTS

A total of 58 patients met our inclusion criteria. The retethering rate in our patient cohort was 5.2% (3/58); one of the three patients developed two episodes of a retethering. Patients with an unchanged conus level, no improvement in the syringomyelia, and an unchanged thickness of the spinal cord postoperatively seem to have a significant higher risk to develop a retethering episode in the follow-up.

CONCLUSION

Retethering after transection of the filum terminale did occur more often than expected. Certain existing factors on the routine postoperative MR images may help to identify patients with an increased likelihood to develop a retethering episode. These results may contribute to improve the follow-up for patients after transection of a TFT and may facilitate adequate treatment.

Towards Guideline-Based Management of Tethered Cord Syndrome in Spina Bifida: A Global Health Paradigm Shift in the Era of Prenatal Surgery

An estimated 60% of the world's population lives in Asia, where the incidence of neural tube defects is high. Aware that tethered cord syndrome (TCS) is an important comorbidity, the purpose of this systematic review was to explore the treatment of TCS among individuals living with spina bifida (SB) in Asia. MEDLINE and Embase databases were searched for relevant studies published from January 2000 to June 2018. Search terms such as 'spinal dysraphism,' 'spinabifida,' 'diastematomyelia,' 'lipomeningocele,' 'lypomyelomeningocele,' 'meningomyelocele,' and 'tethered cord syndrome' were used in diverse combinations. Of the 1,290 articles that were identified in accordance with PRISMA (Preferred Items for Systematic Reviews and Meta-Analyses) guidelines, 15 Asia-based studies met the inclusion criteria. Significant differences in the diagnostic criteria and management of TCS were documented. As the surgical techniques for prenatal closure of the spinal defect continue to evolve, their adoption internationally is likely to continue. In this setting, a clear and evidence-based approach to the definition and management of TCS is essential. The recent publication by the Spina Bifida Association of America of their updated care guidelines may serve as a tool used to promote a systematized approach to diagnosing and treating TCS among individuals with SB in the region, as well as globally.

Recurrent tethered cord: radiological investigation and management

INTRODUCTION

Recurrent tethered cord (RTC) is almost the rule after the repair of myelomeningocele and quite frequent after the repair of lipomyelomeningocele, resulting from the adhesions of the placode within a too narrow spinal canal. About one-third of patients with myelomeningocele and 10 % of those with spinal lipoma develop symptomatic RTC, mainly caused by the ischemic-metabolic injuries due to the cord stretching. The goal of this review is to provide information about the pathophysiology, the radiological picture, and the management of RTV according to the pertinent literature and the authors' experience.

RADIOLOGICAL INVESTIGATION

The magnetic resonance imaging (MRI) picture is characterized by a low position of the conus and by tethering of the spinal cord to the subcutaneous scar or to the inner surface of the spinal canal. The radiological work-up always includes brain MRI, to rule out other possible causes of late neurological deterioration (as shunt malfunction), and MRI of the whole spinal cord, to detect possible associated lesions (syringomyelia, dermoids, etc.). X-rays and/or computed tomography scan of the spine is required for the assessment of scoliosis or other bony malformations.

MANAGEMENT

The surgical treatment is planned after a multidisciplinary neurological, urological, orthopedic, physiatric, and radiological evaluation. The surgical detethering is carried out cautiously, possibly with electrophysiological intraoperative monitoring. Surgery ensures improvement or stability of the clinical picture in 70-80 % of cases, the remaining 20-30 % of patients needing multiple operations for their recovery. Complications may affect up to one-third of operated patients, being mainly represented by CSF leak, pseudomeningocele, and shunt malfunction.

Features of the lumbar spine on magnetic resonance images following sectioning of filum terminale

OBJECT

Spinal cord tethering due to a thickened filum terminale is a well-described entity that can be treated surgically. Postoperative MR imaging of the lumbar spine is performed for unrelated issues or for the development of new symptoms suggestive of cord retethering. A lack of radiological criteria for successful detethering makes interpretation of postoperative MR images challenging. The delineation of postoperative radiological characteristics of a sectioned filum terminale is therefore valuable to clinicians managing these often complex cases.

METHODS

The clinical data for 16 patients who underwent sectioning of a fatty and thickened filum between 2001 and 2010 and in whom pre- and postoperative MR imaging studies were available were analyzed. Medical records were interrogated for preoperative neurological examination, operative details, and postoperative follow-up. The MR images were examined by both a neurosurgeon and a neuroradiologist to assess postoperative radiological characteristics.

RESULTS

The patients' age at time of surgery ranged from 0.3 to 19.8 years (mean 7.5 years). Postoperative MR imaging was performed between 0.03 and 7.36 years after the procedure (mean 2.5 years). Indications for postoperative imaging included new neurological symptoms (11 of 16 patients), routine interval imaging (3 of 16), and possible development of pseudomeningocele (2 of 16). Filum discontinuity was confirmed in 79% of cases postoperatively. Filum remnants appeared thicker after surgery in most cases (80%), a phenomenon most often appreciated in the cephalad end of the sectioned filum. Postoperatively, the conus was elevated in 5 cases (31%) and was found to be more ventrally located in 7 cases (44%).

CONCLUSIONS

Discontinuity, along with thickening of the upper and lower remnants of a sectioned filum, may constitute important radiological features of a detethered filum. Radiological signs of conus relaxation, signified by elevation or a more ventral position, although reassuring, were less reliably observed postoperatively. Because it may be difficult to know if the goals of surgery were met on purely clinical grounds in this patient population, knowledge of the postoperative characteristics of a sectioned filum may aid the practicing neurosurgeon in the management of these complex cases.

Retethering of transected fatty filum terminales

OBJECT

Untethering of a tethered spinal cord (TSC) by transecting or removing a fatty filum terminale is a relatively simple procedure that can prevent or ameliorate neurological symptoms, and the postoperative prognosis is usually good. Progressive neurological deterioration caused by recurrent tethering has been rarely reported. The authors present their experience in cases in which a sectioned fatty filum terminale has become retethered.

METHODS

The authors retrospectively analyzed the surgical results of pediatric patients with fatty filum terminale-TSC treated by transection of the filum. The patients' charts were reviewed for demographic data, clinical presentation, surgical therapy, and follow-up data.

RESULTS

Of the 225 children who underwent TSC release by sectioning the fatty filum from 1992 to 2005, there were 6 patients (2.7%; 3 males, 3 females) in whom the fatty filum retethered. The mean age at the first diagnosis of TSC was 5.2 years (range 2 months-12.3 years). The mean duration from the first untethering procedure to retethering was 5.4 years. The mean age at the time of retethering was 10.6 years (range 7-17.5 years). Symptoms of retethering were urinary incontinence, low-back pain, difficulty walking, constipation, leg pain, and worsening foot deformity. Patients underwent cystometrography at the time retethering was indicated by increased bladder capacity, large post-void residual volume, decreased bladder capacity, increase in filling pressure, and poor sensation of filling. Magnetic resonance imaging revealed adherence of the rostral stump of the sectioned filum to the midline dorsal dural surface. All patients underwent the second untethering procedure. Four patients improved neurologically and experienced no retethering thereafter (mean follow-up period 5.5 years). Two patients experienced additional retethering after temporary improvement following the second untethering procedure.

CONCLUSIONS

Retethering of the spinal cord is a rare condition occurring after the sectioning of a fatty filum terminale. Awareness of this rare sequela is necessary for appropriate long-term management of TSC caused by a fatty filum terminale. Cystometrography is useful for detecting the lesion and confirming the diagnosis of retethering.

Tethered cord syndrome: a review of the literature from embryology to adult presentation

Tethered cord syndrome (TCS) is a clinical condition of various origins that arises from tension on the spinal cord. Radiographic findings may include the conus medullaris in a lower than normal position, fatty infiltration of the filum terminale, lipomyelomeningocele, myelomeningocele, myelocystocele, meningocele, split cord malformations, dermal sinus, anorectal malformations, and intraspinal tumors. The clinical constellation of signs and symptoms associated with TCS may include dermatologic, urological, gastrointestinal, neurological, and orthopedic findings. The current review focuses on TCS by age group of the more common causes of the condition, including myelomeningocele, lipomyelomeningocele, as well as the adult presentation of occult TCS. Pertinent review of the neuroembryology and normal anatomical position of the conus medullaris is included.

Embryopathogenetic surgicoanatomical classification of dysraphism and surgical outcome of spinal lipoma: a nationwide multicenter cooperative study in Japan

OBJECT

The natural history of asymptomatic spinal lipoma in infancy remains unclear, and the indication for the prophylactic untethering operation is still debatable. To address this question, a multicenter cooperative study for the treatment of spinal lipoma was performed by the 7 most active institutions in neurosurgical care for spina bifida in Japan between 2001 and 2005.

METHODS

Patients were classified using the embryopathogenetic surgicoanatomical classification. Their neurosurgical postoperative course was analyzed using the Spina Bifida Neurological Scale. Among 261 patients, 159 were asymptomatic and 102 were symptomatic.

RESULTS

Of the 136 patients for whom prophylactic surgeries were performed, 135 remained asymptomatic and only 1 (0.4%) of the 261 patients presented with mild sensory disturbance. Mild foot deformity was identified in 1 (4.3%) of 23 conservatively observed patients. Of 100 symptomatic patients, deterioration after surgery was seen in 6%, and improvement in 44%. Complete resolution of symptoms was seen in only 14.2%. Filar types for patients > 3 years old improved in Spina Bifida Neurological Scale scores from 12.3 to 14.0. The mean age of symptomatic patients with lipomyelomeningocele was the youngest of all (1.3 years), which indicates lipomyelomeningocele may deteriorate in early infancy. Improvements from surgery were seen for all types of lipoma except the caudal type, presenting at an older mean age (15 years).

CONCLUSIONS

A low rate of postsurgical worsening indicates that surgeries for asymptomatic and symptomatic lipomas are safe. Surgeries done after the onset of symptoms seldom cure the patients. These two results support early untethering for any kind of lipoma; however, further study of the natural history is required.

Outcome of untethering for symptomatic spina bifida occulta with lumbosacral spinal cord tethering in 31 patients: analysis of preoperative prognostic factors

BACKGROUND CONTEXT

The most important goal for treating symptomatic lumbosacral spinal cord tethering is early untethering.

PURPOSE

To investigate preoperative symptoms that may have affected the outcome.

STUDY DESIGN

Patients with or without improvement and with or without favorable outcome after untethering were compared retrospectively by chart and image review.

PATIENT SAMPLE

Thirty-one patients (age between 2 days to 25 years) with spina bifida occulta and symptomatic cord tethering were analyzed. Presenting symptoms (neurological deficits, urological dysfunction, and lower limb deformities) were assessed before and after untethering.

OUTCOME MEASURES

Favorable outcome was defined as complete relief of symptoms or mild symptoms whereby patients are able to look after their own personal care without assistance. Unfavorable outcome was defined as moderate or severe disability whereby patients are unable to attend to their own bodily needs without assistance, are bedridden, or require constant nursing attention.

METHODS

Differences in patient characteristics and presenting symptoms were compared between those with and without clinical improvement and favorable outcome. Multivariate logistic regression was used to identify prognostic factors affecting the outcome.

RESULTS

The average age at surgery was 7.2 years, with a male-to-female ratio of 1.2. The average follow-up time was 4 years. At least one of the following symptoms was present in all patients: neurological deficits (83.9%), urological dysfunction (77.4%), or limb deformities (38.7%). After untethering, all patients had either symptoms stabilized (14 patients, 45.2%) or improved (17 patients, 54.8%), and 14 patients (45.2%) achieved total resolving of symptoms. Logistic regression confirmed that younger age (< or =2 years, odds ratio [OR] 22.0, p=.026), lipomas of filum terminale (OR 25.6, p=.042), and a poor anal tone (OR 10.4, p=.061) were positive prognostic factors for the improvement in symptoms. The functional outcome was determined by the age at surgery (OR 0.9 per year since 1 year old, p=.04) and the presence of limb deformities (OR 0.06, p=.017).

CONCLUSIONS

In conclusion, our study suggests that untethering should be performed immediately once the patient shows evidence of symptomatic lumbosacral cord tethering, irrespective of age. Untethering can interrupt progression of symptoms, but sphincter dysfunction and muscle weakness are more likely to improve or resolve. Benefits can be seen in all patients, but young children (before 2 years old) have a higher chance to gain favorable outcome. Retethering is a main concern during follow-up, particularly for the more complicated lipomyelomeningoceles. Investigations using electrophysiologic and urodynamic studies are helpful for early detection of subtle symptomatic cord tethering or retethering.

Fetal spina bifida repair--current trends and prospects of intrauterine neurosurgery

Myelomeningocele is a common dysraphic defect leading to severe impairment throughout the patient's lifetime. Although surgical closure of this anomaly is usually performed in the early postnatal period, an estimated 330 cases of intrauterine repair have been performed in a few specialized centers worldwide. It was hoped prenatal intervention would improve the prognosis of affected patients, and preliminary findings suggest a reduced incidence of shunt-dependent hydrocephalus, as well as an improvement in hindbrain herniation. However, the expectations for improved neurological outcome have not been fulfilled and not all patients benefit from fetal surgery in the same way. Therefore, a multicenter randomized controlled trial was initiated in the USA to compare intrauterine with conventional postnatal care, in order to establish the procedure-related benefits and risks. The primary study endpoints include the need for shunt at 1 year of age, and fetal and infant mortality. No data from the trial will be published before the final analysis has been completed in 2008, and until then, the number of centers offering intrauterine MMC repair in the USA is limited to 3 in order to prevent the uncontrolled proliferation of new centers offering this procedure. In future, refined, risk-reduced surgical techniques and new treatment options for preterm labor and preterm rupture of the membranes are likely to reduce associated maternal and fetal risks and improve outcome, but further research will be needed.

Ambulation in adults with myelomeningocele. Is it possible to predict the level of ambulation in early life?

OBJECTIVE

The objective of this study was to evaluate the prediction of ambulation in adults with myelomeningocele from muscle strength testing and ambulation in early life.

MATERIALS AND METHODS

Fifty-two myelomeningocele (MMC) individuals at the age 18-37 years at follow-up were studied. Information on muscle strength and ambulatory function in early life was retrieved from medical records. The motor levels determined by the muscle strength were used to predict ambulatory function later in life. At follow-up, a clinical examination was performed.

RESULTS

Of 20 MMC individuals assessed with muscle strength within the first year of life, 7 achieved the predicted ambulatory function, 6 had a better, and 7 a poorer function. Of 32 individuals with known muscle strength at the age of 5-8 years, 10 had function as predicted, 5 a better ambulatory function, and 17 had a poorer ambulation in adult life than predicted. Good strength in quadriceps muscles gave significant better prospect for adult walking. Of the 52 participants, 41 retained their ambulation status from 5-8 years of age.

CONCLUSION

For MMC individuals with motor levels L3-L5, adult ambulatory function cannot be determined from muscle strength in early life, while it to some extend can be predicted for motor levels at or above L2 and at or below S1. The majority of the participants who at the age 5-8 years were community walkers without walking aid kept that function.

Urodynamic Evaluation in Children With Lipomeningocele: Timing for Neurosurgery, Spinal Cord Tethering and Followup

PURPOSE

We assessed the usefulness of urodynamic testing for determining the optimal timing of surgery and for evaluating the development of bladder function in children with lipomeningocele.

MATERIALS AND METHODS

We retrospectively evaluated 64 patients (40 females) 3 to 17 years old (mean 8.5) with lipomeningocele. Patients were divided into 3 groups based on age at surgery, ie younger than 12 months (34 patients), 12 to 36 months (17) and older than 36 months (13). All patients underwent urodynamic testing preoperatively and during extended followup (mean 6.5 years, range 3 to 12).

RESULTS

Bladder capacity and mean detrusor leak pressure improved in all groups but particularly in patients operated on within the first year of life. At the end of the study mean bladder capacity was 420 cc in patients younger than 12 months, 300 cc in those 12 to 36 months old and 260 cc in those older than 36 months (p <0.01), and mean detrusor leak pressure was 37, 54 and 55 cm H(2)O, respectively (p <0.01). At the latest followup 65% of patients in the youngest group had improved urodynamic parameters vs 33% of those 12 to 36 months old and 28% of those older than 36 months.

CONCLUSIONS

Urodynamic evaluation and the presence of neurological impairment have crucial roles in determining the optimal timing of surgery in patients with lipomeningocele, and in diagnosing the onset of tethered cord. Our data show that early surgical repair seems to reduce the risk of neurological deterioration of the lower urinary tract, and allows a more physiological development of urinary function.

Adult tethered cord syndrome in patients with postrepair myelomeningocele: an evidence-based outcome study

OBJECT

As patients with myelomeningocele age, tethered cord syndrome (TCS) in adults with postrepair myelomeningocele has become more common. The authors have structured an evidence-based review of the literature for the purpose of addressing the following questions. (1) How is the diagnosis made? (2) What is the natural history that occurs in adults with postrepair myelomeningocele and TCS? (3) What are the criteria for operative intervention? (4) What is the functional outcome for patients with postrepair myelomeningocele?

METHODS

A computerized search of the National Library of Medicine of the English-language literature published from 1966 to 2003 was performed. Articles pertaining to the clinical aspects and management of postrepair myelomeningocele in adults, TCS in adults resulting from closed defects, and pediatric patients with postrepair myelomeningocele were reviewed. No Level 1 or 2 data were located; however, the search yielded Level 3 and 4 evidence in the literature in which the clinical syndrome, underlying pathology, and the imaging and electrophysiological evaluation for TCS in adults are discussed.

CONCLUSIONS

Analysis of the available data indicates the following. (1) A lower lesion level predisposes patients to symptomatic tethering; moreover, orthopedic and urological deterioration will occur in the majority of these patients. (2) Tethered cord release should be considered for adult patients with postrepair myelomeningocele when clinical symptoms, imaging studies, urodynamics, and somatosensory evoked potentials are consistent with TCS. (3) Prompt, aggressive untethering surgery within 5 years of symptom onset, along with long-term follow up to check for delayed retethering, is recommended. The overall outcome for patients with postrepair myelomeningocele may not be as good as the outcome for adults with closed dysraphism.

The initial treatment of meningocele and myelomeningocele lesions in adulthood: experiences with seven patients

This is a retrospective study of patients having undergone surgical treatment of spina bifida cystica (SBC) lesions in adulthood. The objectives were to assess the clinical, radiological, and surgical characteristics of SBC lesions in adults. There is almost no study assessing these characteristics. Seven adult male patients with SBC lesions, ages between 20 and 23 (mean 21.1), had their primary evaluations between 1995 and 1999 in the Military Hospital, Yzmir, and Gülhane Military Medical Academy, Ankara. A temporary cerebrospinal fluid leak in the patient with the thoracic lesion and a temporary partial urinary incontinence in the patient with the lumbosacral lesion occurred. The most common preoperative complaint was low back pain. This improved in three of four patients (75%) but did not disappear. Although it is rare, an adult with an untreated SBC is a possible entity. These lesions should be included in the differential diagnosis of dorsal midline lesions in adults. Even though they appear as a simple spinal meningocele clinically, preoperative MR imaging and CT are necessary and helpful in the precise diagnosis and surgical planning.

Retethering of sectioned fibrolipomatous filum terminales: report of two cases

OBJECTIVE AND IMPORTANCE

The release of a tethered spinal cord by sectioning a thickened filum terminale is a straightforward surgical procedure that can prevent, arrest, or ameliorate neurological deficits. We recently recognized progressive neurological deterioration caused by filum retethering in two patients years after this procedure was performed. This sequela of a recurrent tethered cord after the sectioning of a filum terminale has not previously been described.

CLINICAL PRESENTATION

Two female patients, each 13 years of age at presentation, had been previously operated on for tethered spinal cords secondary to fibrolipomatous (fatty) fila terminale. Both presented with bladder dysfunction and one with progressive paraparesis. Magnetic resonance images revealed a low-lying conus medullaris and a sectioned filum with the proximal stump adherent to the posterior dura.

INTERVENTION

Each patient underwent neurosurgical exploration of the previous site of sectioning, with the recognition of a retethered proximal stump of the filum terminale. After rerelease of the fatty filum, the patient with only bladder dysfunction stabilized and a motor examination revealed normal results for the patient with progressive paraparesis.

CONCLUSION

Retethering of the spinal cord is a rare sequela after the sectioning of a tight filum terminale. The clinical presentation is typical for recurrent cord tethering, and the radiographic findings are subtle. Careful surgical exploration should be offered for spinal cord untethering. Awareness of this rare and hitherto undescribed sequela is necessary for appropriate long-term management of tethered spinal cord caused by a fatty filum terminale.

Closed spinal dysraphism: a review on diagnosis and treatment in infancy

This article reviews the clinical presentation, pathophysiology, diagnostic strategies, and therapeutic management of closed spinal dysraphism in infancy. Four groups of symptoms are distinguished: (1) cutaneous abnormalities, (2) lower motor neuron dysfunction due to congenital spinal and nerve root abnormalities, (3) upper motor neuron dysfunction due to tethering of the spinal cord, and (4) symptoms caused by associated malformations. Guidelines are proposed concerning timing and type of diagnostic investigations in infancy. This essentially encompasses a neurological assessment, including spinal ultrasonography and nuclear magnetic resonance imaging of the spine and the brain, and a urological assessment, including ultrasonography of kidneys and bladder, cystourethrography and a urodynamic study. As to the tethered cord syndrome it is concluded that first, already in infancy, a progressive neurological dysfunction can be detected; second, surgical untethering should be performed only upon appearance of upper motor neuron signs or upon progression of lower motor neuron signs. Despite its frequently asymptomatic course, the diagnosis of a congenital lumbosacral lipoma, and in the more general sense, of a closed spinal dysraphism, implies a periodic, multidisciplinary follow-up for life.

Impact of urodynamic studies on the surgical management of spinal cord tethering

To determine the usefulness of urodynamic studies in the management of children with a suspected tethered spinal cord, the authors retrospectively reviewed case records of 25 patients evaluated both pre- and postoperatively using this diagnostic adjunct. All patients were also evaluated with magnetic resonance imaging or computerized tomography myelography. Seven patients who presented initially with orthopedic deformity, skin stigmata, and neurological problems underwent primary cord untethering (Group 1). All seven patients were urologically asymptomatic; all but one had normal findings on urodynamic study. Eighteen patients with prior myelomeningocele closure underwent secondary untethering (Group 2). They presented with urological (11 cases), neurological (three cases), or both urological and neurological (four cases) deterioration. All patients underwent surgery via a microsurgical technique. At a mean follow-up time of 2 years, the only Group 1 patient with preoperative abnormal urodynamic findings normalized following untethering, whereas another asymptomatic patient showed worsened results on his postoperative study. In Group 2, all seven patients with preoperative neurological deterioration improved. Ten of the 15 patients who had isolated or associated preoperative clinical urological deterioration improved or stabilized, whereas five displayed continued deterioration in their bladder function. With respect to urodynamic studies, there was a significant increase in total and pressure-specific bladder capacities following untethering. We conclude that urodynamic studies are useful both diagnostically and in follow-up examinations of patients with tethered cord, that disturbances identified by these studies often precede clinical manifestations of deterioration, and that spinal cord untethering favorably influences the urological status in most patients.

Neurological and medico-social problems of spina bifida patients in adolescence and adulthood

Chronological changes in the neurological manifestations of spina bifida are well recognized in the early developmental periods: fetal, neonatal, infantile, pre-school and school life. However, little has been written about the medical and medico-social problems of spina bifida patients in adulthood. Patients now in this age group had the condition diagnosed and managed in an era when modern neurosurgical concepts were only just beginning to be established with the aid of invasive methodology. In our series of 141 cases of spina bifida, 18 patients (13.5%) were over 16 years of age. These included 9 cases each of spina bifida aperta (myeloschisis) and spina bifida occulta (spinal lipoma). The ages ranged from 16 to 47 years (mean: 23.5 years) in the former and from 16 to 57 years (mean: 29.2 years) in the latter group. During the long-term follow-up with quantitative analysis of the spinal neurological changes using the spina bifida neurological scale (SBNS), the final outcomes appeared very grave. Except for 1 case in each group-1 grade III in the spina bifida aperta group and 1 grade II in the spina bifida occulta group-all patients over the age of 27 years were classed as having grade IV disease. There were 2 patients with spina bifida aperta in whom postoperative paraplegia appeared after delayed radical repair (at the ages of 3 years and 18 years) and 3 patients with spina bifida occulta in whom obvious neurological deterioration was observed as the natural history with ongoing paraparesis at the spinal level or late onset of sexual problems. The other group included 2 patients with spinal lipoma in whom late neurological deterioration was observed and who were obliged to undergo a second operation in spite of aggressive early procedures performed during infancy. Among the patients with spina bifida aperta, 2 had marked ventriculomegaly as a form of long-standing overt ventriculomegaly in the adult (LOVA). After the CSF shunt procedure both these patients had problems with delicate shunt dependence and requested fine shunt flow regulation. Two patients in this group also suffered from severe depression. This study involves a limited number of patients, but it may be useful for reference on various points: (1) future prospects for the management of pediatric cases of spina bifida as practiced in the majority of hospitals; (2) natural histories of untreated cases and surgical indications for preventive procedure in spinal lipoma in early infancy; and (3) internationally differing levels of management of spina bifida and the historical development of individual countries' approaches to the problems.

Surgical treatment of late neurological deterioration in children with myelodysplasia

Late deterioration of the neurological condition in patients operated on for myelomeningocele repair has been repeatedly reported in the literature. At the present time magnetic resonance imaging (MRI) allows one to recognize various pathological conditions which can be amenable to surgical correction in these patients, such as Chiari type II malformation, hydro/syringomyelia, decompensated hydrocephalus, and tethered spinal cord. The authors report their experience with 26 myelodysplastic children operated on for myelomeningocele repair in the early neonatal period, who exhibited late deterioration at variable time intervals from the first operation. The children were examined pre-operatively by means of MRI; the results were compared with those provided by MRI in 46 myelodysplastic children who underwent the investigation as a routine follow-up control. The MRI findings were subdivided into 4 main groups of increasing severity from 1 to 4; in some subjects, associated pathological conditions (Chiari II malformation, hydromyelia, etc.) were detected as well. Twenty-two out of the 26 patients with late neurological deterioration were operated on. Eleven of them (grades 2 to 4) underwent detethering of the fixed conus, with an improvement of their clinical picture from mild to good. On the other hand the remaining 11 subjects (grades 1 to 2) improved their condition following the correction of the associated abnormalities (malfunctioning CSF shunt: 5 cases; hydromyelia: 4 cases; symptomatic Chiari II malformation: 2 cases).

Occult dysraphism in adulthood: clinical course and management

We present a series of 23 patients with dysraphic malformations and adult onset of symptoms (4 meningoceles, 19 spinal hamartomas). Mean age at presentation was 39 +/- 21 years (range 23-67 years). Patients were followed up for a mean period of 19 months (range 0.5-68 months). Only patients with progressive neurological disease were operated on (3 meningoceles and 16 spinal hamartomas). The remaining patients were treated conservatively and continue to be observed clinically. Two of three patients operated for meningoceles improved without recurrence of symptoms. Patients with spinal hamartomas could be divided into two groups according to their main symptom: paraparesis (group A, n = 8) or pain (group B, n = 11). Malformations in group B were typically associated with a tethered cord and tended to be more complex than in group A. The majority of patients in group A showed better long-term results than patients in group B, due to their considerably lower rate of recurrence.

[Magnetic resonance imaging in spinal dysraphisms]

We studied by magnetic resonance imaging the incidence of associated malformations in a group of 38 patients with diagnosis of spina bifida followed in our outpatient clinic. Twenty-two children were born with spina aperta and 16 with spina bifida occulta. Tethered cord was found in the majority of patients of both groups. Syringomyelia was found in 13 patients. The craniocervical region was studied in 11 patients with the diagnosis of spina bifida aperta; Chiari malformation was found in 8. The results point to the fact that asymptomatic malformations detected by MRI techniques are frequent in patients with spina bifida.

Treatment and prevention of tethered and retethered spinal cord using a Gore-Tex surgical membrane

The incidence of the tethered cord syndrome after repair of spinal dysraphism is not insignificant. A retethered spinal cord may also develop after an untethering operation. In order to treat and/or prevent the tethered and retethered spinal cord, the authors developed and successfully used a new method in 12 cases. After complete release and reconstruction of the spinal cord, a Gore-Tex surgical membrane was placed over the cord and fixed to the lateral dural surface with stay sutures. During a postoperative follow-up period ranging from 23 months to 7 years, no further neurological deterioration was observed in the 12 patients and magnetic resonance imaging studies showed no adhesion of the spinal cord to the operative site. It is concluded that this simple new method is effective for the treatment and prevention of tethering and/or retethering of the spinal cord, although a longer follow-up study is required.

The neurosurgical implications of continuous neurourological surveillance of children with myelodysplasia

Between 1979 and 1990, 148 newborns with myelodysplasia were followed with serial urodynamic studies and neurological assessment. Of the patients 59 (40%) exhibited changes in neurological status by age 5 years, of whom 28 (19%) showed signs of deterioration. Most changes occurred before age 2 years. A total of 22 children underwent repeat neurosurgical exploration because of a change in urethral sphincter innervation (17), deterioration of function of the lower extremities (3), or changes on computerized tomography or magnetic resonance imaging (2). Postoperative urodynamic evaluation demonstrated improvement in 11 children, stabilization in 9 and further deterioration in 2. The earlier that a change was detected and secondary surgery was performed, the better the outcome. These findings indicate that the neurological lesion in myelodysplasia is a dynamic disease process requiring continuous neurological, orthopedic and urodynamic surveillance. Early identification and prompt neurosurgical reexploration seem to arrest and even reverse the neurological deterioration that takes place in a substantial number of these children.

Tethered cord after spina bifida aperta: a longitudinal study of somatosensory evoked potentials

Progressive neurological deterioration may occur after meningomyelocele repair. Magnetic resonance imaging almost invariably demonstrates a conus medullaris in an abnormally low position, whether neurological symptoms develop or not. Surgery of a secondary tethered cord is indicated when progression of neurological symptoms is documented. We performed a longitudinal study of posterior tibial nerve somatosensory evoked potentials (SSEPs) in children and adolescents after neonatal meningomyelocele repair. All patients were able to walk. Declining or negative posterior tibial nerve SSEPs were recorded in 15 patients; 14 of these had clinical signs of a secondary tethered cord. After surgery of the tethered cord, the SSEPs improved in 8 of 10 patients. Posterior tibial nerve SSEPs may contribute to the diagnosis of secondary tethered cord. After untethering, the evoked potentials demonstrate recovery of spinal cord function and might help to delineate prognosis.

A proposed grading and scoring system for spina bifida: Spina Bifida Neurological Scale (SBNS)

Neurological symptoms present in neonates with spinal dysraphism often progress with growth. A simple, objective scoring system for quantitative analysis of spinal neurological deficits, called the Spina Bifida Neurological Scale (SBNS), is proposed. Scoring is based on (1) motor function, (2) reflexes, and (3) bladder and bowel function. These are each divided into six, four, and five points respectively with respect to the level of spinal function. Motor function and reflexes are bilaterally analyzed, and the maximum SBNS score of 15 points reflects a normal spinal neurological state (grade I). This scoring system was correlated with the clinical condition of 89 patients with spina bifida who were graded from I to V. A total score of less than 5 was associated with a nonambulatory state (grade IV or V) in 84.0% of patients, and a score of 5-9 was associated with an ambulatory state (grade III) in 93.8% of patients. Scores of 10-14 reflected control of bladder and bowel function (grade II) in all patients. The application of a standardized scoring scheme will assist in the evaluation of patients' clinical status and will enable analysis of chronological changes in neurological function.

Tethered cord syndrome in myelodysplasia: correlation between level of lesion and height at time of presentation

The purpose of this study was to determine whether the onset of tethered cord syndrome is related to the level of the myelomeningocele (MMC) (sacral, low lumbar, high lumbar or thoracic) and the height and age of the patient at time of presentation. Of 163 patients followed, 18 underwent corrective surgery for symptomatic tethered cord syndrome. The level of lesion at time of presentation correlated highly with height and age. The mean height and age for each level at the time of surgery were: sacral 134.5cm, 9.3 years; low lumbar: 124cm, 9.9 years; high lumbar: 108cm, 4.9 years; thoracic: 92.4cm, 4.7 years. The author concludes that the sensorimotor level of patients with MMC is a useful clue in predicting the onset of symptoms related to tethered cord syndrome.