Pathophysiology of tethered cord syndrome and other complex factors

Proteomic study of cerebrospinal fluid in adult tethered cord syndrome: Chemical structure and function of apolipoprotein B

Adult tethered cord syndrome (ATCS) has a hidden onset and delayed clinical symptoms. The purpose of this study is to identify hub proteins in the cerebrospinal fluid of ATCS patients through bioinformatics analysis, and to find significant heterogeneity in these proteins between ATCS patients and non ATCS patients (control group). Firstly, differential genes were screened based on proteomic results. Compared with the control group, 18 differentially expressed proteins were upregulated and 18 differentially expressed proteins were downregulated in the cerebrospinal fluid of ATCS patients. Then, GO, KEGG, and GESA functional enrichment analysis showed that ATCS patients were active in biological processes such as coagulation, inflammatory response, and regulation of humoral immune response, suggesting the possibility of spinal cord injury. In addition, protein network interaction analysis indicates that APOB, APOC3, FGA, and FGG are defined as hub proteins. The correlation between ATCS patients and immune characteristics was analyzed using the CIBERSORT algorithm, which may have generated a unique immune microenvironment. Finally, Western blotting was used to experimentally validate APOB, APOC3, FGA, and FGG. The results showed that APOB, APOC3, FGA, and FGG were upregulated in the cerebrospinal fluid of ATCS patients and had an important impact on the repair and functional maintenance of spinal cord injury. They can be used as key proteins for early and accurate diagnosis and treatment of spinal cord thrombosis syndrome, and suggest that the spinal cord of ATCS patients may be damaged, which can serve as potential therapeutic targets.

Nondysraphic Intradural Spinal Lipoma: A Case Report and Review of Pathogenesis

Intradural spinal lipomas are rare benign lesions typically located in the lumbosacral region and associated with spinal dysraphism in children. When unassociated with spinal dysraphism, they are most often diagnosed in young children or adolescents following the emergence of neurological symptoms. In their most rare form, intradural spinal lipomas may be found in adults without spinal dysraphism. Here, we present a case of a 42-year-old female with an intradural spinal lipoma without dysraphism at the T10-T11 level, demonstrating the diagnostic challenge of atypical lipomas and the importance of timely assessment and management. We also reviewed the embryopathogenesis of the different types of intradural spinal lipomas and the importance of surgical interventional planning and approach.

Walking recovery after tethered cord release

After myelomeningocele (MMC) repair, a secondary tethered spinal cord occurs in almost all patients. The tethered spinal cord may result in progressive neurological deterioration and walking disability. This retrospective cohort study aimed to highlight the walking recovery one year after tethered cord release and its relation to the preoperative conus level. We reviewed the medical records at our university hospital from January 2014 to December 2022. The patients who underwent spinal cord untethering following lumbosacral MMC repair were included. We assessed the walking recovery one year after cord release using the modified Benzel scale. Thirty-seven patients met our selection criteria. There were 19 girls (51.4%) and 18 boys (48.6%). Their mean age at presentation was 8.6 years. The preoperative conus vertebral levels ranged between L4 and S3. One year after spinal cord release, 37.8% of the patients regained their walking ability. All the patients whose preoperative conus level was at S2 or S3 regained their walking ability. In contrast, all the patients with preoperative conus levels at L4 or L5 didn't regain their ability to walk. One-third (33.3%) of patients whose conus was at the S1 level regained their walking ability one year after cord release. One year after tethered cord release, 37.8% of the patients regained their walking ability. We found that the walking recovery was statistically associated with the preoperative conus level. A multicenter prospective study is required to support the results of this study.

New Spinal Shortening Technique for Tethered Cord Syndrome: A Technical Note

Background and Objectives: To present a new spinal shortening technique for tethered cord syndrome. Tethered cord syndrome (TCS) is a debilitating condition leading to progressive neurological decline. Surgical detethering for TCS is the gold standard of treatment. However, symptomatic retethering of TCS has been reported in 5%-50% of patients after initial release. To solve this problem, posterior spinal shortening osteotomy has been reported. This technique has risks of massive blood loss and neurological deterioration. The authors hereby report a new safe spinal shortening technique for tethered cord syndrome. Materials and Methods: A 31-year-old man with gait disturbance was referred to our hospital. After the delivery of treatment, he underwent surgical untethering of the spinal cord in another hospital. He had hyperreflexia of the Achilles tendon reflex and bilateral muscle weakness of the legs (MMT 3-4). He also had urinary and bowel incontinence, and total sensory loss below L5. An anteroposterior lumbar radiogram indicated partial laminectomy of L3 and L4. Lumbar MRI showed retethering of spinal cord. Results: The patient underwent a new spinal shortening technique for tethered cord syndrome under the guidance of O-arm navigation. First, from the anterior approach, disectomy from T12 to L3 was performed. Second, from the posterior approach, Ponte osteotomy was performed from T12 to L3, shortening the spinal column by 15 mm. The patient was successfully treated surgically. Postoperative lumbar MRI showed that the tension of the spinal cord was released. Manual muscle testing results and the sensory function of the left leg had recovered almost fully upon final follow-up at one year. Conclusions: A retethered spinal cord after initial untethering is difficult to treat. This new spinal shortening technique can represent another good option to release the tension of the spinal cord.

The Surgical Histopathology of the Filum Terminale: Findings from a Large Series of Patients with Tethered Cord Syndrome

This study investigated the prevalence of embryonic and connective tissue elements in the filum terminale (FT) of patients with tethered cord syndrome (TCS), examining both typical and pathological histology. The FT specimens from 288 patients who underwent spinal cord detethering from 2013 to 2021 were analyzed. The histopathological examination involved routine hematoxylin and eosin staining and specific immunohistochemistry when needed. The patient details were extracted from electronic medical records. The study found that 97.6% of the FT specimens had peripheral nerves, and 70.8% had regular ependymal cell linings. Other findings included ependymal cysts and canals, ganglion cells, neuropil, and prominent vascular features. Notably, 41% showed fatty infiltration, and 7.6% had dystrophic calcification. Inflammatory infiltrates, an underreported finding, were observed in 3.8% of the specimens. The research highlights peripheral nerves and ganglion cells as natural components of the FT, with ependymal cell overgrowth and other tissues potentially linked to TCS. Enlarged vessels may suggest venous congestion due to altered FT mechanics. The presence of lymphocytic infiltrations and calcifications provides new insights into structural changes and mechanical stress in the FT, contributing to our understanding of TCS pathology.

Advances in Fetal Surgical Repair of Open Spina Bifida

Spina bifida remains a common congenital anomaly of the central nervous system despite national fortification of foods with folic acid, with a prevalence of 2-4 per 10,000 live births. Prenatal screening for the early detection of this condition provides patients with the opportunity to consider various management options during pregnancy. Prenatal repair of open spina bifida, traditionally performed by the open maternal-fetal surgical approach through hysterotomy, has been shown to improve outcomes for the child, including decreased need for cerebrospinal fluid diversion surgery and improved lower neuromotor function. However, the open maternal-fetal surgical approach is associated with relatively increased risk for the patient and the overall pregnancy, as well as future pregnancies. Recent advances in minimally invasive prenatal repair of open spina bifida through fetoscopy have shown similar benefits for the child but relatively improved outcomes for the pregnant patient and future childbearing.

Utilizing pre- and postoperative radiological parameters to predict surgical outcomes following untethering for tethered cord syndrome in a pediatric population

OBJECTIVE

Tethered cord syndrome (TCS) can lead to significant downstream neurological deficits including gait deterioration, incontinence, and often unexplained chronic low-back pain. Surgical intervention may relieve symptoms, but there are no defined radiological parameters associated with surgical outcomes and functional status. The authors aimed to define pre- and postoperative radiological parameters for assessing surgical outcomes in TCS.

METHODS

The authors performed a single-center retrospective review of all pediatric patients treated for TCS between 2016 and 2021. Patient baseline characteristics and operative metrics included age, sex, level of conus, level of procedure, tethering pathology, symptoms at presentation, complications, improvement of symptoms, and reoperation rate. MRI measurements included pre- and postoperative anterior canal distance (ACD) and bending angle (BA).

RESULTS

Thirty-three pediatric patients were identified who underwent untethering of the spinal cord and had pre- and postoperative MRI between 2016 and 2021. The mean patient age was 5.64 ± 5.33 years. Twenty patients (60.60%) were female. Regarding the site of untethering, 31 procedures (93.93%) were performed at the lumbosacral region and 2 (6.06%) were performed at the thoracolumbar region. The conus medullaris was found above L3 in 21.21% of patients. Postoperatively, 18.18% of patients experienced complications, 48.48% showed improvement in their symptoms, and 48.48% were equivocal or had persistent symptoms. The mean preoperative ACD0 (measured from the posterior vertebral body margin [middle] to the anterior margin of the conus medullaris) was 6.15 ± 3.18 mm, the postoperative ACD0 was 2.25 ± 2.72 mm, and the average change in ACD0 was -0.90 ± 1.31 mm. The mean preoperative BA was 26.00° ± 11.56°, the mean postoperative BA was 15.92° ± 9.81°, and the average change in BA was -10.08° ± 8.80°. An optimal cutoff value for preoperative BA to predict reoperation in pediatric patients with complex TCS undergoing surgery was ≥ 31.70° (area under the curve = 0.83).

CONCLUSIONS

In surgically treated patients with TCS, certain preoperative radiological parameters may be important in predicting postoperative surgical outcomes; these parameters can be evaluated and reported to indicate patients at high risk for complications. Further prospective multicenter research is warranted to offer robust evidence of association of patient outcomes with preoperative radiological parameters in TCS.

Complicated Neuraxial Anesthesia in a Patient With Tethered Spinal Cord

Spinal anesthesia is a common anesthetic used in many surgical procedures. Anatomical variations and diseases make this procedure require extra considerations. Extra care should be taken into consideration in the pre-anesthesia evaluation when neuraxial anesthesia is planned.

We present the case of a patient undergoing cesarean section for the arrest of labor, who had a complicated labor course due to unrecognized history of a tethered spinal cord leading to inadequate analgesia, requiring replacement of epidural analgesia and spinal anesthesia. Ultimately, the decision was made to proceed with general anesthesia due to the patient’s discomfort. Exhaustive chart review after surgery showed a past MRI with evidence of a tethered spinal cord.

Secondary tethered cord syndrome in adult patients: retethering rates, long-term clinical outcome, and the effect of intraoperative neuromonitoring

BACKGROUND

The strategy for surgical treatment of tethered cord syndrome in pediatric patients is well established but still bares challenges for adult patients. This retrospective study was performed to assess the surgical outcome of adult patients with a secondary tethered cord syndrome and to evaluate the benefit of intraoperative neuromonitoring.

METHODS

Clinical charts of 32 consecutive adult patients who underwent in total 38 surgical untethering procedures at our facility between 2008 and 2018 were retrospectively analyzed. Epidemiological data, MRI scans, and postoperative results were evaluated.

RESULTS

The retethering rate in our patient cohort was 16%. Main complaints were maximal pain (82%), bladder dysfunction (79%), paresthesia (68%), and weakness in the lower extremities (68%). Forty-eight months after surgery, patients' symptoms generally improved, with an average level of pain of 19.1% (95% CI, 5.7-32.5%), paresthesia 28.7% (95% CI, 12.6-44.8%), weakness in the lower extremities 27.7% (95% CI, 11.1-44.4%), and bladder dysfunction 60.2% (95% CI, 41.6-78.7%). The use of neuromonitoring appears to have a positive impact on patient weakness (OR = 0.07; 95% CI, 0.01-0.68) and paresthesia (OR = 0.03; 95% CI, 0.00-2.18). This benefit is less clear for the retethering rate (OR = 0.45; 95% CI, 0.06-3.26) or the overall clinical outcome (OR = 0.70; 95% CI, 0.14-3.45). The presence of a preoperative Chiari syndrome, syringomyelia, or scoliosis had no relevant influence on the retethering rate.

CONCLUSIONS

Our data confirms that untethering surgery in adult patients is relatively safe and has a reasonable chance of clinical improvement of pain, paresthesia, and weakness in the lower extremities. The use of intraoperative monitoring has a positive influence on the improvement of preoperative paralysis.

Spinal Cord Tethering, a Very Rare Cause of Cauda Equina Syndrome after Lumbar Disk Surgery: A Case Report

Tethered cord syndrome (TCS) may rarely remain asymptomatic until degenerative or nondegenerative lumbar diseases superimpose in adulthood and expose the hidden anomaly. In such cases, different treatment options can be selected and simultaneous detethering might be considered too. We are reporting an undiscovered TCS in a young lady who underwent lumbar diskectomy due to symptomatic disk extrusion and suffered complete cauda equina syndrome (CES), postoperatively.

Expression of Sigma-Class Glutathione-S-Transferase in Fetal and Pediatric Filum Terminale Samples: A Comparative Study

Background and objectives: The pathophysiology of tethered cord syndrome (TCS) in children is not well elucidated. An inelastic filum terminale (FT) is the main factor underlying the stretching of the spinal cord in TCS. Our study aimed to investigate the expression of glutathione-S-transferase (GST) in children and fetal FT samples in order to understand the relationship between this enzyme expression and the development of TCS. Materials and Methods: FT samples were obtained from ten children with TCS (Group 1) and histological and immunohistochemical examinations were performed. For comparison, FT samples from fifteen normal human fetuses (Group 2) were also analyzed using the same techniques. Statistical comparison was made using a Chi-square test. Results: Positive GST-sigma expression was detected in eight (80%) of 10 samples in Group 1. The positive GST-sigma expression was less frequent in nine (60%) of 15 samples from Group 2. No statistically significant difference was detected between the two groups (p = 0.197). Conclusions: Decreased FT elasticity in TCS may be associated with increased GST expression in FT. More prospective studies are needed to clarify the mechanism of the GST-TCS relationship in children.

Expression profiles of pro-inflammatory and pro-apoptotic mediators in secondary tethered cord syndrome after myelomeningocele repair surgery

PURPOSE

The literature on histopathological and molecular changes that might underlie secondary tethered cord syndrome (TCS) after myelomeningocele (MMC) repair surgeries remains sparse. To address this problem, we analyzed specimens, which were obtained during untethering surgeries of patients who had a history of MMC repair surgery after birth.

METHODS

Specimens of 12 patients were analyzed in this study. Clinical characteristics were obtained retrospectively including pre-operative neurological and bowel/bladder-function, contractures and spasticity of lower extremities, leg and back pain, syringomyelia, and conus position on spinal MRI. Cellular marker expression profiles were established. Further, immunoreactivities (IR) of IL-1ß/IL-1R1, TNF-α/TNF-R1, and HIF-1α/-2α were analyzed qualitatively and semi-quantitatively by densitometry. Co-labeling with cellular markers was determined by multi-fluorescence-labeling. Cytokines were further analyzed on mRNA level. Immunostaining for cleaved PARP and TUNEL was performed to detect apoptotic cells.

RESULTS

Astrocytosis, appearance of monocytes, activated microglia, and apoptotic cells in TCS specimens were one substantial finding of these studies. Besides neurons, these cells co-stained with IL-1ß and TNF-α and their receptors, which were found on significantly elevated IR-level and partially mRNA-level in TCS specimens. Staining for HIF-1α/-2α confirmed induction of hypoxia-related factors in TCS specimens that were co-labeled with IL-1ß. Further, hints for apoptotic cell death became evident by TUNEL and PARP-positive cells in TCS neuroepithelia.

CONCLUSIONS

Our studies identified pro-inflammatory and pro-apoptotic mediators that, besides mechanical damaging and along with hypoxia, might promote TCS development. Besides optimizing surgical techniques, these factors should also be taken into account when searching for further options to improve TCS treatment.

Fully Endoscopic Interlaminar Detethering of Spinal Cord in Tethered Cord Syndrome: A Case Report and Technical Description

A 19-year-old man presented with long lasting significant back and bilateral leg pain, and hypoesthesia on the lateral side of both his thighs for which he had undergone several courses of medication and bouts of physical therapy treatment. His urodynamic parameters were normal and lumbar magnetic resonance imaging (MRI) revealed a low-lying conus at the L2-3 level with a thickened fatty filum, and he was diagnosed as having tethered cord syndrome (TCS). The patient underwent a fully endoscopic detethering through an interlaminar approach with intraoperative neurophysiological monitoring. The thickened filum terminale was located and then the filum was coagulated and cut. The patient showed a significant improvement in his preoperative symptoms, and reported no problems at 2-year follow-up. Detethering of the spinal cord in tethered cord syndrome using a fully endoscopic interlaminar approach provides the advantages of minimal damage to tissues, less postoperative discomfort, early postoperative recovery, and a shorter hospitalization.

Retrospective magnetic resonance imaging evaluation of fatty filum terminale in Kuwaiti population

Objective:

Thickened fatty filum terminale (FFT) can cause tethered cord syndrome (TCS) and can be easily diagnosed on magnetic resonance (MR) imaging. We aimed to assess a) the incidence, distribution and clinical significance of the incidentally detected FFT in Kuwaiti population and b) the relationship between degenerative disk disease (DDD) and thickness of the FFT.

Materials and Methods:

A retrospective study was planned at Jaber Al Ahmad Armed Forces Hospital, Kuwait involving 1111 patients. A 1.5T GE machine was used for MR imaging to acquire multiplanar MR sequences. MR images of lumbar spine in 1111 subjects were reviewed and location, size, tightness of FFT, the DDD and clinical details were evaluated.

Results:

FFT was observed in 43 out of 1111 (3.9%) subjects based on MRI, out of which 11 were females and 32 were males. The mean distance between the tip of conus medullaris and the FFT was 41 mm. The mean diameter of the FFT was 1.74 mm. 40 of 43 patients had DDD of varying severity on MR images and no significant or appreciable slackness of FFT was observed in these cases. There were no clinical symptoms related to FFT associated with degenerated disks.

Conclusion:

FFT is frequently observed in Kuwaiti male population. No significant slackness of FFT was observed in cases with varying severity of DDD. There were no clinical symptoms related to FFT with or without degenerated disks.

A new model of tethered cord syndrome produced by slow traction

The development of a suitable animal model is important for clarifying the pathogenesis of tethered cord syndrome (TCS). This study was undertaken to develop a new animal model for investigating the pathogenesis and therapeutic strategies for TCS. A traction device, a filum terminale tractor, was designed exclusively for this experiment. A TCS model was produced in cats using the tractor to fixate the filum terminale to the dorsal aspect of the second sacrum. The responses to tethering were evaluated by electron microscopy and electromyography for detection of somatosensory evoked potentials (SEPs) and motor evoked potentials (MEPs) at designated time points. Progressive swaying gait and lameness in clinical performance were observed with cord traction. Histopathological examination revealed an association between the increasing traction in the spinal cord and the increase in impaired nerve cells. No changes of SEPs and MEPs were detected in the untethered cats, while the latencies of SEPs and MEPs significantly increased in the tethered cats. The TCS model established in this study is simple and reproducible, in which varying degrees of tension could be applied to the neural elements.

Tethered cord due to caudal lipomeningocele associated with a lumbar dural arteriovenous fistula

A 29-year-old man presented with progressive paraparesis associated with sensory impairment in both lower limbs for the past 2 years. He was experiencing the sensation of incomplete urinary evacuation. The patient had undergone an earlier operation for a lumbar lipomeningocele at birth. Magnetic resonance images of the lumbosacral spine showed a low-lying conus medullaris adherent to a caudal lipoma. There was a leash of abnormal vascular channels in the adjacent subarachnoid space. The patient underwent spinal angiography that revealed a dural arteriovenous fistula (AVF) principally fed by the left fourth lumbar (L-4) radicular branch. At surgery the cord was detethered by disconnection of the sacral lipoma. The dural fistula was obliterated by occlusion of the L-4 radicular feeder close to the nidus of the fistula. Postoperatively, the patient experienced an immediate relief of sensation of tightness in both lower limbs. There was a gradual improvement of power and sensation at the 6-month follow-up examination. According to the authors' literature search, the present case is a unique report of a rare association of spinal cord tethering due to a caudal lipoma associated with a lumbar dural AVF. The present report discusses the etiopathology, presentation, and management of this case.

Microsurgical fenestration of idiopathic intramedullary cysts in adult patients

PURPOSE

The aim of this study is to describe the findings in one of the largest series of microsurgically treated intramedullary cysts investigated by magnetic resonance imaging (MRI), focusing on the peri- and intraoperative setup including detailed neurological and radiological outcome analyses.

METHODS

Retrospective analysis of patients with intramedullary cyst who had undergone microsurgical fenestration at our department between 2006 and 2011. Preoperative three-dimensional constructive interference of steady-state MRI was conducted to optimize surgical planning. Intraoperative electrophysiological monitoring included motor-evoked potentials, somatosensory-evoked potentials, and electromyogram. Clinical outcome as well as pre-, postoperative and long-term MRI scans were evaluated.

RESULTS

Eight female patients (median age 58.0 years, range 32-72 years) with a median clinical follow-up of 48.0 months (range 2-69 months) were included. Seven cysts were located in the conus medullaris, one in the cervical spine. Overall, 25.0% (2/8) showed complete remission of preoperative symptoms, 62.5% (5/8) improved, and 12.5% (1/8) asymptomatic patients remained unchanged. Pain syndromes (4/4) as well as motor deficits (2/2) improved in all affected patients and bladder dysfunction (3/4) displayed a high tendency for improvement. Postoperative MRI scans showed permanently decreased cyst volumes by ~80%.

CONCLUSION

Microsurgical fenestration of intramedullary cysts using preoperative high-resolution imaging and intraoperative electrophysiological monitoring is a safe and effective treatment option for symptomatic patients.

Clinical significance of imaging and histological characteristics of filum terminale in tethered cord syndrome

OBJECT

The pathophysiology of tethered cord syndrome (TCS) is uncertain; however, it has been suggested that fibrous and fatty elements within the filum terminale (FT) play a role. The objective of this study was to describe the radiological and histological features of the FT in TCS and determine if there are associations between those features and clinical outcomes, complications, and urodynamics.

METHODS

In this retrospective study, histological, MRI, and clinical data obtained in 293 patients with TCS who underwent FT transection were reviewed and analyzed in a multivariate analysis.

RESULTS

The median patient age was 4.9 years (range 0.3-64.3 years). On MRI, a fatty filum was present in 65% of patients and a thickened filum (> 2 mm) was seen in 45%. Histologically, the FT contained prominent fibrous tissue in 95%, nerve twigs in 79%, adipose tissue in 59%, and vascular tissue in 36%. Histological features associated with a thickened filum on MR images were adipose tissue (OR 3.5, p < 0.001), nerve twigs (OR 2.2, p = 0.028), and vascular tissue (OR 0.5, p = 0.025). Adipose tissue was associated with a conus level below the L2-3 disc space (OR 2.3, p = 0.031) and with a fatty filum on imaging (OR 9.8, p < 0.001). Nerve twigs were associated with abnormal urodynamics (OR 10.9, p = 0.049). The only variable predictive of clinical improvement was conus level; patients with conus levels caudal to L-2 were less likely to improve postoperatively (OR 0.3, p = 0.042).

CONCLUSIONS

Fibrous tissue was ubiquitous and may be important in the pathophysiology of TCS. Nerve twigs and adipose tissue were associated with abnormal urodynamics and low-lying coni, respectively. Although the majority of patients clinically improved, patients with normal conus levels had significantly better outcomes.

Detethering of a congenital tethered cord in adult patients: an outcome analysis

BACKGROUND

Tethered spinal cord syndrome (TCS) is characterized by attachment of the spinal cord down toward the tail end of the spine, comprising the danger of myelopathic symptoms. We retrospectively analyzed postoperative neurological outcome in adult patients with congenital TCS with special regard to the extent of resection of concomitant intraspinal lipomas.

METHODS

Medical records of 27 adult patients with congenital TCS (both with and without associated spinal lipomas) undergoing microsurgical detethering were systematically analyzed. Neurophysiological monitoring was available and feasible for all cases. Outcome parameters were preoperatively and postoperative neurological status; Wilcoxon rank test was used for statistical analysis.

RESULTS

In all patients, complete detethering was achieved. While urinary symptoms remained stable, all patients showed a non-significant tendency towards improvement of sensorimotor deficits. Both, patients with and without spinal lipoma experienced a significant postoperative amelioration of back pain. Patients with lipoma were found to suffer significantly less from radicular pain postoperatively (3/16). Furthermore, patients with a history of pain shorter than 1 year showed a significantly better chance for postoperative relief from back and radicular pain. The extent of lipoma resection had no significant impact on postoperative outcome.

CONCLUSIONS

Adult patients with symptomatic TCS profit from detethering, especially regarding relief of lower back and radicular pain. Complete removal of associated spinal lipomas does not seem to be mandatory for achieving a satisfying result.

Use of prone position magnetic resonance imaging for detecting the terminal filum in patients with occult tethered cord syndrome

Object

The pathophysiology of occult tethered cord syndrome (OTCS) with no anatomical evidence of a caudally shifted conus and a normal terminal filum is hard to understand. Therefore, the diagnosis of OTCS is often difficult. The authors hypothesized that the posterior displacement of the terminal filum may become prominent in patients with OCTS who are in a prone position if filum inelasticity exists, and they investigated prone-position MRI findings.

Methods

Fourteen patients with OTCS and 12 control individuals were examined using T2-weighted axial MRI with the patients in a prone position on a flat table. On each axial view, the distance between the posterior and anterior ends of the subarachnoid space (A), the distance between the posterior end of the subarachnoid space and the terminal filum (B), the distance between the posterior end of the subarachnoid space and the dorsal-most nerve among the cauda equina (C), and the distance between the posterior end of the subarachnoid space and the ventral-most nerve (D) were measured. The location ratios of the terminal filum, the dorsal-most nerve, and the ventral-most nerve were calculated by the ratio of A to B (defined as TF = B/A), A to C (defined as DN = C/A), and A to D (defined as VN = D/A), respectively. Patients underwent sectioning of the terminal filum with the aid of a surgical microscope. The low-back pain Japanese Orthopaedic Association score was obtained before surgery and at the final follow-up visit.

Results

On prone-position axial MRI, the terminal filum was separated from the cauda equina and was shifted caudally to posterior in the subarachnoid space in all patients with OTCS. The locations of the caudal cauda equina shifted to ventral in the subarachnoid space. The TF values in the OTCS group were significantly lower than those in the control group at the L3–4 (p = 0.023), L-4 (p = 0.030), L4–5 (p = 0.002), and L-5 (p < 0.001) levels. In contrast, the DN values in the OTCS group were significantly higher than those of the control group at the L-2 (p = 0.003), L2–3 (p = 0.002), L-3 (p < 0.001), L3–4 (p < 0.001), L-4 (p = 0.007), L4–5 (p = 0.003), and S-1 (p = 0.014) levels, and the VN values in the OTCS group were also significantly higher than those of the control group at the L2–3 (p = 0.022), L-3 (p = 0.027), L3–4 (p = 0.002), L-4 (p = 0.011), L4–5 (p = 0.019), and L5–S1 (p = 0.040) levels. Sections were collected during surgery for histological evaluation, and a decreased elasticity within the terminal filum was suggested. Improvements in the Japanese Orthopaedic Association score were observed at the final follow-up in all patients.

Conclusions

The authors' new method of using the prone position for MRI shows that the terminal filum is located significantly posterior and the cauda equina is located anterior in patients with OTCS, suggesting a difference in elasticity between the terminal filum and cauda equina.

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.

When only partial spinal cord detethering is possible

In most instances, initial surgery to untether a tethered spinal cord is successful. But what happens when it is not? The authors describe the case of a now 18-year-old woman with spina bifida in whom surgery for tethered cord was required on two occasions. In both instances, due to the extent of her underlying lesion and fibrous tissue, only partial detethering was possible without acutely sacrificing significant neurological function. The authors detail the patient's course and review the peer-reviewed scientific literature on outcomes in patients in whom only partial cord detethering is achieved. In their review of all case series and clinical studies pertaining to the surgical treatment of tethered cord syndrome identified during an online search of 2184 scientific abstracts and 2 major neurosurgery textbooks, excluding the present case, the authors identified 53 confirmed or presumed cases of incomplete detethering in eight articles, incorporating 390 patients, for an overall prevalence of roughly 13.6%. Although no investigators have reported statistical comparisons of outcomes in those in whom just partial and complete detethering has been achieved, the evidence generally suggests poorer outcomes in the former. Prospective multicenter studies addressing this important issue clearly are warranted. To date, the authors believe that incomplete detethering is grossly underreported in the medical literature.

Children with tethered cord syndrome of different etiology benefit from microsurgery-a single institution experience

PURPOSE

The term "tethered cord syndrome" (TCS) illustrates, according to the literature, both a separate diagnosis, as well as a combination of symptoms in the context of dysraphic conditions. The common denominator is the increased tension and abnormal stretching of the spinal cord, caused by tissue attachments that limit its movement in the spinal canal. In light of the fact that no real data exists regarding the management of these patients, the purpose of this single institutional study is to underscore management strategies and discuss the results, pitfalls, and the treatment of pediatric patients with tethered cord syndrome.

METHODS AND RESULTS

The clinical outcome in 20 pediatric patients was studied retrospectively. Ten children with closed spinal dysraphism, nine with tethering after postpartum myelomeningocele repair, and one child with an infected open dermal sinus were included. A total of 22 detethering procedures were performed. The most common symptoms prior to surgery were muscle weakness and urinary dysfunction, followed by foot deformities and pain. Of all symptoms, pain responded most favorably to surgical treatment. There was improvement in 11 out of 15 patients with preoperative motor deficits, while that was the case in 11 out of 16 patients with urinary dysfunction.

CONCLUSIONS

In view of the lack of evidence regarding the treatment of children with tethered cord syndrome, the best way to aim for a favorable outcome is correct indication for surgical intervention, combined with the implementation of technical advancements, such as intraoperative neurophysiological monitoring and ultrasound.

Intrathecal endoscopy to enhance the diagnosis of tethered cord syndrome

OBJECT

Tethered cord syndrome (TCS) is being diagnosed in an increasing number of adults and late teens. Before referral to neurosurgeons, however, the majority of patients in this group suffers back and leg pain for a long period without a definitive diagnosis. The diagnostic difficulty derives from 2 factors: the signs and symptoms are subtle and easily overlooked, and the combination of an elongated cord and a thickened filum is lacking in 65% of patients. When a patient presents with signs and symptoms typical for TCS but demonstrates no elongated cord or thickened filum on MR imaging, one must search for a more reliable finding to establish a diagnosis of TCS. Based on the authors' earlier surgical experiences, posterior displacement of the terminal filum is consistently found at surgery in all patients with TCS. In previous publications they interpreted this finding as the lower cord and filum traveling along the concave side of the lumbosacral spinal canal to minimize cord tension. In the present prospective study, the authors attempt to confirm posterior displacement of the filum terminale by using intrathecal endoscopy prior to wide exposure of the spinal cord and filum. Further, the stretch test was applied to the terminal filum to evaluate its elasticity.

METHODS

Sixty-eight patients with signs and symptoms as well as MR imaging studies indicative of TCS underwent endoscopic examination of the filum and cauda equina. After lumbar or sacral laminectomy, a flexible endoscope was inserted through a small dural and arachnoid incision into the subarachnoid space. The filum and cauda equina fibers were identified. Once the dura mater and arachnoid were opened widely, a stretch test was done to confirm filum inelasticity. In 3 patients, percutaneous endoscopy was also performed before open surgery to determine its applicability as compared with the open method.

RESULTS

On inserting the endoscope into the intrathecal space, the filum was immediately identified medioposterior to the cauda equina fibers in all 68 patients. The stretch test revealed a lack of filum elasticity in all patients. Preoperative percutaneous endoscopy was equally effective in identifying the position of the filum.

CONCLUSIONS

Currently, endoscopic identification of the posteriorly displaced filum, which was confirmed at open surgery, is the essential diagnostic study for TCS or the tethered spinal cord. Furthermore, the stretch test of the filum proves its inelasticity, and filum sectioning leads to ascension and relaxation of the caudal spinal cord. These results can be linked to the impaired oxidative metabolism of the lumbosacral cord under excessive tension and to the metabolic and neurological improvements seen after filum sectioning.

Management of recurrent adult tethered cord syndrome

Recurrent tethered cord syndrome (TCS) can lead to significant progressive disability in adults. The diagnosis of TCS is made with a high degree of clinical suspicion. In the adult population, many patients receive inadequate care unless they are seen at a multidisciplinary clinic. Successful detethering procedures require careful intradural dissection and meticulous wound and dural closure. With multiple revision procedures, vertebral column shortening has become an appropriate alternative to surgical detethering.

Spinal cord traction, vascular compromise, hypoxia, and metabolic derangements in the pathophysiology of tethered cord syndrome

OBJECT

The definition of tethered cord syndrome (TCS) relies mainly on radiological criteria and clinical picture. The presence of a thickened filum terminale and a low-lying conus medullaris in symptomatic patients is indicative of TCS. The radiological definition of TCS does not take into account cases that involve a normal-lying conus medullaris exhibiting symptoms of the disease.

METHODS

The authors performed a MEDLINE search using the terms "tethered cord" and "pathophysiology." The search returned a total of 134 studies. The studies were further filtered to identify mostly basic research studies in animal models or studies related to the biomechanics of the filum terminale and spinal cord.

RESULTS

Spinal cord traction and the loss of filum terminale elasticity are the triggers that start a cascade of events occurring at the metabolic and vascular levels leading to symptoms of the disease. Traction on the caudal cord results in decreased blood flow causing metabolic derangements that culminate in motor, sensory, and urinary neurological deficits. The untethering operation restores blood flow and reverses the clinical picture in most symptomatic cases.

CONCLUSIONS

Although classically defined as a disease of a low-lying conus medullaris, the pathophysiology of TCS is much more complex and is dependent on a structural abnormality, with concomitant altered metabolic and vascular sequelae. Given the complex mechanisms underlying TCS, it is not surprising that the radiological criteria do not adequately address all presentations of the disease.

Posterior vertebral column subtraction osteotomy for the treatment of tethered cord syndrome: review of the literature and clinical outcomes of all cases reported to date

Tethered cord syndrome (TCS) is a debilitating condition of progressive neurological decline caused by pathological, longitudinal traction on the spinal cord. Surgical detethering of the involved neural structures is the classic method of treatment for lumbosacral TCS, although symptomatic retethering has been reported in 5%–50% of patients following initial release. Subsequent operations in patients with complex lumbosacral dysraphic lesions are fraught with difficulty, and improvements in neurological function are modest while the risk of complications is high. In 1995, Kokubun described an alternative spine-shortening procedure for the management of TCS. Conducted via a single posterior approach, the operation relies on spinal column shortening to relieve indirectly the tension placed on the tethered neural elements. In a cadaveric model of TCS, Grande and colleagues further demonstrated that a 15–25-mm thoracolumbar subtraction osteotomy effectively reduces spinal cord, lumbosacral nerve root, and filum terminale tension. Despite its theoretical appeal, only 18 reports of the use of posterior vertebral column subtraction osteotomy for TCS treatment have been published since its original description. In this review, the authors analyze the relevant clinical characteristics, operative data, and postoperative outcomes of all 18 reported cases and review the role of posterior vertebral column subtraction osteotomy in the surgical management of primary and recurrent TCS.

Lateral tethering intraspinal lipoma with scoliosis

The authors present an unusual case of an intradural lipoma at the thoracolumbar level causing lateral tethering of the spine, with complicated scoliosis. A 6-year-old girl was admitted with progressive change in posture detected by her parents. Thoracolumbar scoliosis was detected by physical examination and X-ray studies. Spinal magnetic resonance imaging revealed an intradural lipoma and right lateral tethering of the spine at the upper lumbar level. After surgical release of lateral tethering and resection of the lipoma, fusion was performed by the orthopedic surgery team. Radiological and intraoperative findings of this extremely rare case are discussed.

Neurosurgical management of spinal dysraphism and neurogenic scoliosis

STUDY DESIGN

To review diagnosis and treatment of neurogenic factors implicated in the development of progressive scoliosis.

OBJECTIVE

Increased awareness of neurogenic causes as a contributing component of spinal cord tethering has led to enhanced radiographic surveillance for etiologic factors contributing to the genesis of scoliosis. Review of various manifestations of spinal dysraphism offers better definition of clinical indications for surveillance MRI scans and thus may contribute to improving outcomes for affected individuals.

SUMMARY OF BACKGROUND DATA

Increasing utilization of surveillance MRI has led to a greater awareness of neurogenic causes as contributing factors in the setting of scoliosis. It is imperative for clinicians treating individuals with scoliosis to be aware of the most common etiologies of neurogenic factors as well as be cognizant of the neurosurgical approaches to treating these conditions in a pre-emptive fashion. This will serve to minimize potential neurological complications and offer improved surgical outcomes after instrumentation.

METHODS

Current therapeutic approaches were outlined for various etiologies of neurogenic scoliosis as well as neurosurgical management of the tethered cord, spinal cord tumors in addition to current challenges surrounding Chiari malformations and syringomyelia.

RESULTS

Timely recognition of these frequently progressive conditions may not only prevent irreversible neurologic compromise but may also help to ameliorate or stabilize concurrent scoliosis. Tethered cords are best treated by releasing the affected cord and offers the best opportunity to stabilize or improve the scoliosis. Syringomyelia, often associated with a Chiari malformation, is a well-known progenitor of scoliosis, and addressing the underlying cause with a Chiari decompression frequently leads to a reduction or resolution of the syrinx and may result in a concomitant improvement in scoliosis.

CONCLUSION

Surveillance MRI should be undertaken for scoliosis when there are clinical indications consistent for a tethered cord, spinal cord tumor, or Chiari malformation and associated syringomyelia.

Thoracic disc herniation in a patient with tethered cord and lumbar syringomyelia and diastematomyelia: magnetic resonance imaging and neurophysiological findings

STUDY DESIGN

Case report.

OBJECTIVE

To describe the diagnostic challenges in a patient suffering from thoracic disc herniation (TDH) and spina bifida complicated by multiple lumbar spinal cord abnormalities, i.e., tethered cord, lumbar syringomyelia, and diastematomyelia.

SUMMARY OF BACKGROUND DATA

Advances in neuroimaging, i.e., magnetic resonance imaging, increase the sensitivity to disclose both clinically relevant but also other spine and spinal cord abnormalities. TDH accounts for less than 1% of all surgically treated disc herniations. Syringomyelia and diastematomyelia are comparably rare and present with varying degrees of spinal cord dysfunction.

METHODS

A 54-year-old women presented with progressive pain and sensorimotor symptoms in the lower back and limbs. Neurologic examination revealed lower limb spastic motor deficits and spinal ataxia. Magnetic resonance imaging revealed a T6-T7 disc herniation, with spinal cord signal change in addition to a spina bifida with sacral tethered cord, lumbar syringomyelia, and diastematomyelia. Combined neurophysiological testing identified a neurologic lesion in the mid thoracic cord, with normal lower limb nerve conduction and reflex recordings, but pathologic somatosensory-evoked potential and T6 paravertebral electromyography.

RESULTS

The patient was diagnosed with a clinically relevant T6-T7 disc herniation and underwent successful surgical decompression resulting in electrophysiological improvements.

CONCLUSION

This unique case highlights the value of electrophysiology in the evaluation of a complex spinal disorder in a patient suffering from acquired TDH in the presence of extensive congenital spine and spinal cord abnormalities. Clinical symptoms and signs can be complemented by neurophysiological techniques to improve diagnostic accuracy and improve the basis for treatment recommendations. In cases involving multiple spinal abnormalities, a comprehensive neurophysiological assessment beyond paravertebral electromyography studies, including nerve conduction and somatosensory-evoked potential recordings, is recommended to assist in confirming the diagnosis.

Tethered cord syndrome in identical twins

The diagnosis of tethered cord syndrome (TCS) without typical conus medullaris symptoms and the radiological features such as a low set conus medullaris or dysraphic malformation is difficult. We report 11 year old identical twin brothers with TCS associated with the conus at the normal level. Their presenting symptom was progressive leg pain and both patients underwent surgical interruption of the filum terminale. The pain recurred in one patient treated surgically only after symptom became worse but resolved immediately in the other sibling treated promptly. We indicate the importance of early diagnosis and treatment of TCS to obtain excellent long-term outcome despite the absence of a low set conus or specific symptoms. Furthermore, when a twin or sibling of an affected person has neurological symptoms and the cutaneous signature of spinal dysraphism, radiological examination should be performed to establish the cause.

Spinal cord transection for definitive untethering of repetitive tethered cord

In certain highly selected circumstances, division of a distally nonfunctional or dysfunctional cord can be a means of definitive untethering that spares and protects more rostral neurological function and results in definitive untethering. The authors reviewed their institutional experience with such cases and evaluated the limited literature. Based on their experience, treatment can be effective in carefully selected patients who undergo spinal cord transection, and the rate of repetitive tethered spinal cord can be decreased.

Tight filum terminale syndrome in children: analysis based on positioning of the conus and absence or presence of lumbosacral lipoma

BACKGROUND

Tight filum terminale syndrome (TFTS) characterized by findings consistent with a tethered cord but with the conus ending in a normal position has only recently been observed in children. In this situation, diagnosis may prove difficult and sectioning of the filum terminale is questionable.

MATERIALS AND METHODS

Sixty cases of pediatric TFTS were analyzed by methods including spinal X-ray and magnetic resonance imaging (MRI). Twenty-one patients exhibited a normally positioned conus, 18 a low-lying conus, and 21 a low-lying conus with accompanying lumbosacral lipoma. These three groups were compared preoperatively and postoperatively for lumbosacral cutaneous stigmata, vertebral anomalies, concomitant congenital spinal dysraphisms, lower limb deformities, and sphincter dysfunction.

RESULTS

Rates of occurrence of lumbosacral cutaneous stigmata and other concomitant congenital spinal dysraphisms differed significantly among the groups. Differences in other parameters were not observed. All groups responded positively to surgery.

CONCLUSIONS

Pediatric TFTS may involve a normally positioned conus. Diagnosis of pediatric TFTS should be based on clinical presentation, physical and radiological examinations, MRI, and pathologic changes in the filum. When neurological signs accompany such changes, early severing of the filum is indicated regardless of conus position.

Tethered cord syndrome in children: a review

✓The treatment of a patient with symptoms of a tethered spinal cord and in whom a fatty infiltrated terminal filum is found is controversial. The authors review their experience and the literature regarding this aspect of occult spinal dysraphism. From experience, transection of a fatty terminal filum in patients with symptoms related to excessive caudal cord tension is a minor procedure that generally yields good results. The most problematic issue in the literature is what patients and symptoms are best suited to surgical treatment.

NFIA haploinsufficiency is associated with a CNS malformation syndrome and urinary tract defects

Complex central nervous system (CNS) malformations frequently coexist with other developmental abnormalities, but whether the associated defects share a common genetic basis is often unclear. We describe five individuals who share phenotypically related CNS malformations and in some cases urinary tract defects, and also haploinsufficiency for the NFIA transcription factor gene due to chromosomal translocation or deletion. Two individuals have balanced translocations that disrupt NFIA. A third individual and two half-siblings in an unrelated family have interstitial microdeletions that include NFIA. All five individuals exhibit similar CNS malformations consisting of a thin, hypoplastic, or absent corpus callosum, and hydrocephalus or ventriculomegaly. The majority of these individuals also exhibit Chiari type I malformation, tethered spinal cord, and urinary tract defects that include vesicoureteral reflux. Other genes are also broken or deleted in all five individuals, and may contribute to the phenotype. However, the only common genetic defect is NFIA haploinsufficiency. In addition, previous analyses of Nfia^−/− knockout mice indicate that Nfia deficiency also results in hydrocephalus and agenesis of the corpus callosum. Further investigation of the mouse Nfia^+/− and Nfia^−/− phenotypes now reveals that, at reduced penetrance, Nfia is also required in a dosage-sensitive manner for ureteral and renal development. Nfia is expressed in the developing ureter and metanephric mesenchyme, and Nfia^+/− and Nfia^−/− mice exhibit abnormalities of the ureteropelvic and ureterovesical junctions, as well as bifid and megaureter. Collectively, the mouse Nfia mutant phenotype and the common features among these five human cases indicate that NFIA haploinsufficiency contributes to a novel human CNS malformation syndrome that can also include ureteral and renal defects.

Central nervous system (CNS) and urinary tract abnormalities are common human malformations, but their variability and genetic complexity make it difficult to identify the responsible genes. Analysis of human chromosomal abnormalities associated with such disorders offers one approach to this problem. In five individuals described herein, a novel human syndrome that involves both CNS and urinary tract defects is associated with chromosomal disruption or deletion of NFIA, encoding a member of the Nuclear Factor I (NFI) family of transcription factors. This syndrome includes brain abnormalities (abnormal corpus callosum, hydrocephalus, ventriculomegaly, and Chiari type I malformation), spinal abnormalities (tethered spinal cord), and urinary tract abnormalities (vesicoureteral reflux). Nfia disruption in mice was already known to cause hydrocephalus and abnormal corpus callosum, and is now shown to exhibit renal defects and disturbed ureteral development. Other genes besides NFIA are also disrupted or deleted and may contribute to the observed phenotype. However, loss of one copy of NFIA is the only genetic defect common to all five patients. The authors thus provide evidence that genetic loss of NFIA contributes to a distinct CNS malformation syndrome with urinary tract defects of variable penetrance.

Part 3: examination of the newborn with closed spinal dysraphism

Spinal dysraphism, an incomplete closure of the neural tube, can be open, exposing the neural elements to the environment, or can be closed, covered with skin. Abnormal development of the spine occurs early in life and also interferes with usual development of the skin. This often creates cutaneous markers or stigmata over the area. Cutaneous markers may include a subcutaneous mass, abnormal hair growth, skin dimple, tag or sinus, or unusual pigmentation. Recognizing these markers is important because, although many closed spinal dysraphisms are asymptomatic at birth, neurological sequelae can occur. The sequelae are insidious and often permanent. This article, Part 3 in a series of articles devoted to spinal assessment, reviews closed spinal dysraphisms. The article emphasizes identification of various cutaneous markers associated with closed spinal dysraphisms. Early detection and follow-up may prevent neurologic sequelae for the infant later in life.