Pre- and post-operative hydromyelia in spinal dysraphism

Characterizing syringomyelia and its clinical significance in 140 patients with lipomyelomeningocele

OBJECTIVE

The aims of this study were to characterize syringomyelia in patients with lipomyelomeningocele (LMMC) and investigate the association between the presence of a syrinx and patient neurological deficits.

METHODS

Patients with LMMC who had been admitted between 2007 and 2020 were included in the study. Syringomyelia on magnetic resonance imaging (MRI) was classified into three groups: true syrinx, early syrinx, and presyrinx. The correlation of clinical deficits (at birth, new onset, and progressive) and type of lipoma with the presence and type of syrinx was studied.

RESULTS

Among a total of 140 patients, the median age was 2.5 (IQR 1.3-9) years. Neurological deficits were present at birth in 75 (53.6%) patients, but 67 (47.9%) had new-onset deficits or progression of their birth deficits. The most common type of spinal lipoma was the transitional type (75.7%). Thirty-nine (27.9%) patients had a syrinx (37 with a true syrinx, 2 with an early syrinx), and 25 (17.9%) patients had a presyrinx. There was no significant correlation between the presence of a syrinx and patient neurological deficits. However, patients with a syrinx that was not adjacent to the lipoma (≥ 1 vertebral level away) had a higher incidence of deficits at birth (p = 0.045), whereas those with a syrinx spanning ≥ 5 vertebral levels had a higher incidence of progressive neurological deficits (p = 0.04). Six (75%) of 8 patients in whom serial MRI had shown syrinx progression had clinical worsening.

CONCLUSIONS

Syrinx location with respect to the spinal lipoma, syrinx length, and progressive syringomyelia may have clinical significance in patients with LMMC.

Dermal Sinus Tract associated with Type I and Type II Split Cord Malformation

The dermal sinus tract of the spine is associated with other occult spinal dysraphisms, such as the split cord malformation (diastematomyelia) in a 40% of the cases and embryologically is not clearly defined if the dermal sinus and split cord malformation have origin in gastrulation or late primary neurulation, but the most accepted theory of the dermal sinus tract consists in early incomplete disjunction, which explains the relation with other spinal dysraphisms. Here, we present two cases, with a dermal sinus tract of the spine associated with Type I and Type II split cord malformation.

Curved Planar Reformation for the Evaluation of Hydromyelia in Patients With Scoliosis Associated With Spinal Dysraphism

STUDY DESIGN

A retrospective cohort study.

OBJECTIVE

Scoliosis and hydromyelia have frequently been observed in patients with spinal dysraphism. We investigated the applicability of curved planar reformation (CPR) for evaluating hydromyelia in patients with scoliosis associated with spinal dysraphism.

SUMMARY OF BACKGROUND DATA

It is quite difficult to evaluate scoliosis and hydromyelia in patients with spinal dysraphism.

METHODS

We identified 11 patients with scoliosis and a Cobb angle of >20° among 107 spinal dysraphism patients. In addition to routine T1- and T2-weighted axial and sagittal MRI, we obtained three-dimensional constructive interference in steady-state magnetic resonance imaging (MRI) as sagittal cross-section volume images. The spinal cord and hydromyelia were rendered into a single-plane, two-dimensional image using the straightened CPR technique. In cases of scoliosis with hydromyelia, the sagittal length and maximal diameters of hydromyelia and the spinal cord were measured by three examiners. Measurement errors among examiners were evaluated using standard deviation (SD) and coefficient of variation (CV).

RESULTS

Each series of image sets provided a straightened CPR image that clearly delineated the entire length of the linearized spinal cord in a single plane. The straightened CPR image also demonstrated the accurate lengths and estimated volume of hydromyelia. Given that three of the 11 patients underwent serial MRI during this period, we were able to accurately compare volume changes. In the sagittal length of the hydromyelia, SD and CV were smaller with the straightened CPR technique than with the conventional T2 WI sagittal section in all cases, showing a statistically significant difference between both techniques (SD: P = 0.014, CV: P = 0.013). Even in the measurements, the difference in CV between both techniques was close to statistical significance.

CONCLUSION

The straightened CPR technique is useful for accurately identifying volume changes in hydromyelia, even in patients with severe scoliosis.

LEVEL OF EVIDENCE

1.

Syringomyelia and tethered cord in children

INTRODUCTION

The presence of syringomyelia varies in patients with different forms of dysraphism; from 21 % to 67 %. Only around 60 % of patients with syringomyelia is likely to experience symptoms related to it.

PATHOPHYSIOLOGY

Many theories have been outlined for the creation of syringomyelia. The one most applicable to tethered cord dictates that tensile radial stress may create a syrinx in a previously normal cord tissue and transiently lower pressure may draw in interstitial fluid, causing the syrinx to enlarge if fluid exit is inhibited. In addition, arachnoiditis increases flow resistance in the spinal subarachnoid space, altering temporal CSF pulse pressure dynamics, which promotes entry of CSF in to the spinal cord.

CLINICAL PRESENTATION

There is a significant overlap between the symptoms that are due to tethered cord and syringomyelia, both in newly presenting patients with coexisting syringomyelia, and in previously treated patients who during follow-up present recurrent symptoms and a new syringomyelia cavity.

TREATMENT

The treatment of patients with tethered cord and syringomyelia is directed towards untethering the cord from its most caudal region upwards and restoring spinal anatomy with reestablishment of unobstructed CSF flow in the subarachnoid space. Only if complete untethering has been ensured and syringomyelia deteriorates, then surgical treatment can be directed against the syrinx. In patients with spinal dysraphism and coexisting hydrocephalus, radiological presentation of new syringomyelia or deterioration of previously known syringomyelia may signify shunt obstruction "until proven otherwise".

CONCLUSION

In most occasions, satisfactory cord untethering addresses the development of syringomyelia.

Preuntethering and postuntethering courses of syringomyelia associated with tethered spinal cord

BACKGROUND

There has been controversy regarding the management of syringomyelia associated with tethered spinal cord. Previous reports on the topic have included only a small number of patients, considered open/closed spinal dysraphism together, or had a short follow-up.

OBJECTIVE

To review a uniform group of patients with syringomyelia associated with tethered cord and treated mainly by untethering alone.

METHODS

Of the 135 patients operated on for closed spinal dysraphism between 2003 and 2008, 33 patients with preoperative syringomyelia were identified. The preoperative/postoperative clinical data and syrinx index (ratio of the syrinx area and the cord area) were retrospectively reviewed. The syrinx index of each patient was plotted as an individual graph to outline the temporal change of the syrinx before and after untethering surgery.

RESULTS

Five patients showed symptom progression during the preoperative period, and 4 of the 5 had an additional magnetic resonance imaging before the operation that showed progression of the syringomyelia. Postoperatively, 31 of 32 patients (97%) who underwent postoperative follow-up imaging showed long-term stability or a decrease in the syrinx index. Four symptomatically stable patients showed a transient increase in the syrinx index during the initial postoperative 6 months, which later decreased spontaneously. In 1 patient with retethering, the syrinx index increased 6 months before the onset of new urinary symptoms.

CONCLUSION

Untethering alone may be sufficient for the management of syringomyelia associated with tethered cord. A transient increase in the syrinx index during the initial postoperative period may be observed without additional surgery if patients are symptomatically stable.

Spontaneous regression of lipomyelomeningocele associated with terminal syringomyelia in a child. Case report

The authors present the case of a 3-month-old girl who presented with lipomyelomeningocele (LMM) associated with a low-lying conus and a terminal syrinx. At the time of presentation, the girl had a mild neurological, but congenital, deficit: weakness of the right foot and calf as well as absence of the right ankle reflex. Bladder assessment was normal, and it was decided to monitor this child closely, without performing surgery. Results of further magnetic resonance imaging performed 1 year after diagnosis and when the girl was 28 months old, showed a significant regression of LMM and associated syrinx. Interestingly, the child remained neurologically unchanged. Although described in the literature, spontaneous regression of LMM is a very unusual situation, and very few cases have been reported. This case represents the first report of concomitant regression of an associated syrinx. Close follow-up of nonsurgically treated children is mandatory, as the risk of late deterioration remains.

Diastematomyelia in children: treatment outcome and natural history of associated syringomyelia

OBJECTIVE

To quantify the long-term outcome of children with diastematomyelia and the implication of syringomyelia in the natural history.

MATERIALS

Retrospective study of 17 children (nine girls and eight boys) with diastematomyelia operated during 1989-2004. Mean age at diagnosis was 3.4 years (range 5 days-12 years), mean follow-up was 5 years; 14 had excision of spur and cord untethering, 3 had excision of spur alone.

RESULTS

The bony spur was in the lumbar region in 12 and thoracic in 5 patients. Syringomyelia was present in eight (47%), associated with bony spur between L1 and 4 (p=0.088), spina bifida occulta in ten (58.8%), and spinal lipoma in one (6%). Preoperative Necker Enfants Malades (NEM) scores were 17 in eight patients, 16 in four, 15 in three, 13 in one, and 12 in one patient. Presenting neurological deficits were motor in eight, sensory deficits in three, and anal incontinence in one patient. There was improvement of NEM scores postoperatively in five patients only, but still with residual deficit. Repeat spur excision and cord untethering was performed in three patients for neurological deterioration 1-4 years after first operation. On postoperative MRI scans syringomyelia remained unchanged in all eight patients. There were one skin infection, one transient motor deterioration, and one patient with sensory deficit after surgery.

CONCLUSION

Prophylactic operations were associated with the best clinical outcome. Despite improvement, all patients with established preoperative deficit still had residual neurological deficits at their last follow-up. The associated syringomyelia remained unchanged after surgery, indicating that it does not contribute to the neurological syndrome.

Clinical significance of terminal syringomyelia in association with pediatric tethered cord syndrome

An association between terminal syringomyelia (TS) and tethered cord syndrome (TCS) has been recognized. The clinical significance of TS and the need for concurrent treatment is not known. Thirty-four patients with TCS undergoing surgery for tethered cord release were evaluated for the incidence of TS. The clinical and radiological response to untethering with and without syrinx drainage was assessed. The group incidence of TS was 29.4%. There were no significant differences in the sex, age, underlying pathology or preoperative symptoms between the TCS group (TCS, n = 24) and the TCS group with TS (TCS + TS, n = 10). In the TCS group, 37.5% of the patients were asymptomatic preoperatively, and in the TCS + TS group 50% were asymptomatic preoperatively. After surgery, none of these asymptomatic patients developed symptoms. All of the symptomatic TCS + TS patients improved clinically, 12 of 15 symptomatic TCS patients improved, 2 patients were unchanged and 1 had worsening scoliosis. Syrinx did not develop in patients lacking it preoperatively. In patients where postoperative imaging was available, preoperative syringes improved. TS is clearly associated with TCS. Tethered cord release alone may be sufficient to improve preoperative symptoms and TS may be an associated phenomenon that does not mandate separate treatment.