Pathophysiology of "tethered cord syndrome"

A 31-year follow-up of those with occult spinal dysraphism, who underwent spinal cord untethering: Lower urinary tract function, skin stigmata, fertility, and work participation

OBJECTIVES

This study evaluated patients with occult spinal dysraphism who underwent spinal cord untethering.

METHODS

Twenty-four patients who visited us between 1983 and 2000 were followed-up for a mean duration of 31 years. We studied their lower urinary tract function, skin stigmata, fertility, and work participation.

RESULTS

Questionnaires sent in 2022 revealed that 5 patients had normal voiding (Group A) and 19 patients had abnormal voiding (Group B). Groups A and B underwent spinal cord untethering at a mean age of 5.7 and 13.0 years, respectively, showing a significant statistical difference (p = 0.036). After spinal cord untethering, the number of patients with detrusor normoactivity increased from 0 to 5, i.e., 3 of 6 with detrusor overactivity (50%), 1 of 2 not examined, and 1 of 5 not known. Patients with detrusor underactivity also increased from 11 to 19. Severity of incontinence in the International Consultation on Incontinence Questionnaire-Short Form resulted in a mean value of 2.4 in Group A, which was significantly superior to the mean value of 9.1 in Group B (p = 0.004). Fourteen patients (58.3%) were married and had 21 healthy children. A majority of patients have had full-time jobs. A variety of skin stigmata were present in the lumbosacral region, and changes in vesico-urethral configurations were observed during a video-urodynamic study.

CONCLUSIONS

Our study identified that the early timing of spinal cord untethering performed in neonates or infants and detrusor overactivity prior to untethering surgery are important factors in achieving normal bladder function.

Intraoperative Neurophysiological Monitoring in Tethered Cord Syndrome Surgery: Predictive Values and Clinical Outcome

INTRODUCTION

"Tethered cord syndrome" (TCS) refers to a congenital abnormality associated with neurological signs and symptoms. The aim of surgery is to prevent or arrest their progression. This study reports a retrospective case series of tethered cord syndrome surgeries, supported by intraoperative neurophysiological monitoring.

METHODS

The case series comprises 50 surgeries for tethered cord syndrome in which multimodal intraoperative neurophysiological monitoring was performed using motor evoked potentials (transcranial motor evoked potentials [TcMEPs]), tibial nerve somatosensory evoked potentials (TNSEPs), and pudendal-anal reflex (PAR). The intraoperative neurophysiological monitoring results are reported and correlated with clinical outcomes.

RESULTS

Sensitivity, specificity, and negative predictive value were high for TcMEPs and TNSEPs, while PAR exhibited low sensitivity and positive predictive value but high specificity and negative predictive value. Fisher's exact test revealed a significant correlation between changes in TcMEPs, TNSEPs, and clinical outcome ( P < 0.000 and P = 0.049 respectively), but no correlation was detected between PAR and urinary/anal function ( P = 0.497).

CONCLUSIONS

While TcMEPs and TNSEPs were found to be reliable intraoperative neurophysiological monitoring parameters during tethered cord syndrome surgery, PAR had low sensitivity and positive predictive value probably because the reflex is not directly related to bladder function and because its multisynaptic pathway may be sensitive to anesthetics. New onset muscle weakness and sensory deficits were related to postoperative changes in TcMEPs and TNSEPs, whereas changes in PAR did not predict bladder/urinary impairment. Urinary deficits may be predicted and prevented with other neurophysiological techniques, such as the bladder-anal reflex.

Disparities in indications and outcomes reporting for pediatric tethered cord surgery: The need for a standardized outcome assessment tool

PURPOSE

Tethered cord syndrome (TCS) is characterized by abnormal attachment of the spinal cord neural elements to surrounding tissues. The most common symptoms include pain, motor or sensory dysfunction, and urologic deficits. Although TCS is common in children, there is a significant heterogeneity in outcomes reporting. We systematically reviewed surgical indications and postoperative outcomes to assess the need for a grading/classification system.

METHODS

PubMed and EMBASE searches identified pediatric TCS literature published between 1950 and 2023. Studies reporting surgical interventions, ≥ 6-month follow-up, and ≥ 5 patients were included.

RESULTS

Fifty-five studies representing 3798 patients were included. The most commonly reported non-urologic symptoms were nonspecific lower-extremity motor disturbances (36.4% of studies), lower-extremity/back pain (32.7%), nonspecific lower-extremity sensory disturbances (29.1%), gait abnormalities (29.1%), and nonspecific bowel dysfunction/fecal incontinence (25.5%). Urologic symptoms were most commonly reported as nonspecific complaints (40.0%). After detethering surgery, retethering was the most widely reported non-urologic outcome (40.0%), followed by other nonspecific findings: motor deficits (32.7%), lower-extremity/back/perianal pain (18.2%), gait/ambulation function (18.2%), sensory deficits (12.7%), and bowel deficits/fecal incontinence (12.7%). Commonly reported urologic outcomes included nonspecific bladder/urinary deficits (27.3%), bladder capacity (20.0%), bladder compliance (18.2%), urinary incontinence/enuresis/neurogenic bladder (18.2%), and nonspecific urodynamics/urodynamics score change (16.4%).

CONCLUSION

TCS surgical literature is highly variable regarding surgical indications and reporting of postsurgical outcomes. The lack of common data elements and consistent quantitative measures inhibits higher-level analysis. The development and validation of a standardized outcomes measurement tool-ideally encompassing both patient-reported outcome and objective measures-would significantly benefit future TCS research and surgical management.

Quantitative anatomical analysis of lumbar interspaces based on 3D CT imaging: optimized segment selection for lumbar puncture in different age groups

BACKGROUND

Optimal lumbar puncture segment selection remains controversial. This study aims to analyze anatomical differences among L3-4, L4-5, and L5-S1 segments across age groups and provide quantitative evidence for optimized selection.

METHODS

80 cases of CT images were collected with patients aged 10-80 years old. Threedimensional models containing L3-S1 vertebrae, dural sac, and nerve roots were reconstructed. Computer simulation determined the optimal puncture angles for the L3-4, L4-5, and L5-S1 segments. The effective dural sac area (ALDS), traversing nerve root area (ATNR), and area of the lumbar inter-laminar space (ALILS) were measured. Puncture efficacy ratio (ALDS/ALILS) and nerve injury risk ratio (ATNR/ALILS) were calculated. Cases were divided into four groups: A (10-20 years), B (21-40 years), C (41-60 years), and D (61-80 years). Statistical analysis was performed using SPSS.

RESULTS

1) ALDS was similar among segments; 2) ATNR was greatest at L5-S1; 3) ALILS was greatest at L5-S1; 4) Puncture efficacy ratio was highest at L3-4 and lowest at L5-S1; 5) Nerve injury risk was highest at L5-S1. In group D, L5-S1 ALDS was larger than L3-4 and L4-5. ALDS decreased after age 40. Age variations were minimal across parameters.

CONCLUSION

The comprehensive analysis demonstrated L3-4 as the optimal first-choice segment for ages 10-60 years, conferring maximal efficacy and safety. L5-S1 can serve as an alternative option for ages 61-80 years when upper interspaces narrow. This study provides quantitative imaging evidence supporting age-specific, optimized lumbar puncture segment selection.

Classification of and individual treatment strategies for complex tethered cord syndrome

Objective

To study the classification, diagnosis, and treatment strategies of complex tethered cord syndrome (C-TCS) on the basis of the patients' clinical symptoms, imaging findings, and therapeutic schedule.

Methods

The clinical data of 126 patients with C-TCS admitted to our department from January 2015 to December 2020 were retrospectively analyzed. Classification criteria for C-TCS were established by analyzing the causes of C-TCS. Different surgical strategies were adopted for different types of C-TCS. The Kirollos grading, visual analogue scale (VAS), critical muscle strength, and Japanese Orthopaedic Association (JOA) scores were used to evaluate the surgical outcomes and explore individualized diagnosis and treatment strategies for C-TCS.

Results

C-TCS was usually attributable to three or more types of tether-causing factors. The disease mechanisms could be categorized as pathological thickening and lipomatosis of the filum terminal (filum terminal type), arachnoid adhesion (arachnoid type), spina bifida with lipomyelomeningocele/meningocele (cele type), spinal lipoma (lipoma type), spinal deformity (bone type), and diastomyelia malformation (diastomyelia type). Patients with different subtypes showed complex and varied symptoms and required individualized treatment strategies.

Conclusion

Since C-TCS is attributable to different tether-related factors, C-TCS classification can guide individualized surgical treatment strategies to ensure complete release of the tethered cord and reduce surgical complications.

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.

Surgery for spina bifida occulta: spinal lipoma and tethered spinal cord

The technical evolution of the surgery for spina bifida occulta (SBO) over the course of a half-century was reviewed with special foci placed on the spinal lipoma and tethered spinal cord. Looking back through history, SBO had been included in spina bifida (SB). Since the first surgery for spinal lipoma in the mid-nineteenth century, SBO has come to be recognized as an independent pathology in the early twentieth century. A half-century ago, the only option available for SB diagnosis was the plain X-ray, and pioneers of the time persevered in the field of surgery. The classification of spinal lipoma was first described in the early 1970s, and the concept of tethered spinal cord (TSC) was proposed in 1976. Surgical management of spinal lipoma with partial resection was the most widely practiced approach and was indicated only for symptomatic patients. After understanding TSC and tethered cord syndrome (TCS), more aggressive approaches became preferred. A PubMed search suggested that there was a dramatic increase of publications on the topic beginning around 1980. There have been immense academic achievements and technical evolutions since then. From the authors' viewpoint, landmark achievements in this field are listed as follows: (1) establishment of the concept of TSC and the understanding of TCS; (2) unraveling the process of secondary and junctional neurulation; (3) introduction of modern intraoperative neurophysiological mapping and monitoring (IONM) for surgery of spinal lipomas, especially the introduction of bulbocavernosus reflex (BCR) monitoring; (4) introduction of radical resection as a surgical technique; and (5) proposal of a new classification system of spinal lipomas based on embryonic stage. Understanding the embryonic background seems critical because different embryonic stages bring different clinical features and of course different spinal lipomas. Surgical indications and selection of surgical technique should be judged based on the background embryonic stage of the spinal lipoma. As time flows forward, technology continues to advance. Further accumulation of clinical experience and research will open the new horizon in the management of spinal lipomas and other SBO in the next half-century.

Fetal Tethered Spinal Cord: Diagnostic Features and Its Association with Congenital Anomalies

OBJECTIVE

We assessed the frequency and type of associated congenital anomalies encountered with fetal tethered spinal cord (TSC) determined prenatally.

METHOD

A retrospective review was conducted based on the associated fetal abnormalities following diagnosis of low-lying fetal conus medullaris during the prenatal ultrasound.

RESULTS

Of the 26 fetuses with low-lying conus medullaris, four were solitary TSC and 22 had TSC combined with associated congenital malformations, including four cases with spina bifida occulta, four cases with spina bifida aperta, one case with severe hydrocephalus, and 13 cases with multisystem congenital malformations. Among all the 13 cases with combined multisystem congenital malformations, four cases had vertebral defects, anal anomalies, cardiac defects, trachea-esophageal fistula, renal anomalies, and limb anomalies (VACTERL) syndrome, two cases had combined kidney development abnormalities, one case had cloacal exstrophy (OEIS syndrome), and six cases had chromosomal abnormalities (one case of chromosome 7q deletion, two cases of trisomy 13 syndrome, one case of trisomy 18 syndrome, one case of trisomy 9 syndrome, and one case of chromosome 4p deletion).

CONCLUSIONS

Low-lying conus medullaris found during prenatal ultrasound examination were often associated with neural tube malformations or multi-systemic complex developmental malformations. The frequency of chromosomal abnormalities was 23.1%.

Spinal cord tethering and syringomyelia after trauma: impact of age and surgical outcome

Posttraumatic spinal cord tethering and syringomyelia frequently lead to progressive neurological loss. Although several studies demonstrated favourable outcome following spinal cord detethering with/without shunting, additional research is required as no clear consensus exists over the ideal treatment strategy and knowledge about prognostic demographic determinants is currently limited. In this investigation, we retrospectively investigated 67 patients (56 men, 11 women) who were surgically treated and followed for symptomatic spinal cord tethering and syringomyelia from 2012 to 2022 at our center. Age (B-coefficient 0.396) and severity of trauma to the spinal cord (B-coefficient - 0.462) have been identified as independent predictors for the rate of development of symptomatic spinal cord tethering and syringomyelia (p < 0.001). Following untethering surgery including expansion duraplasty with/without shunting, 65.9% of patients demonstrated an improvement of neurological loss (p < 0.001) whereas 50.0% of patients displayed amelioration of spasticity and/or neuropathic pain (p < 0.001). Conclusively, active screening for symptomatic spinal cord tethering and syringomyelia, particularly in younger patients with severe spinal trauma, is crucial as surgical untethering with/without shunting is able to achieve favourable clinical outcomes. This knowledge may enable clinicians to tailor treatment strategies in spinal cord injury patients suffering from progressive neurological loss towards a more optimal and personalized patient care.

Electrodiagnostic findings of retethering in children with spinal dysraphism

PURPOSE

Retethering of the cord can occur after the initial untethering surgery. Typical neurological manifestations indicative of cord tethering are often difficult to determine in pediatric patients. Patients who had a primary untethering operation are likely to present with some degree of neurological deficits from a previous tethering event, and urodynamic studies (UDSs) and spine images are frequently abnormal. Therefore, more objective tools to detect retethering are needed. This study sought to delineate the characteristics of EDS of retethering, and therefore, could support the diagnosis of retethering.

METHODS

Among 692 subjects who had an untethering operation, data from 93 subjects who had been suspected of retethering clinically were retrospectively extracted. The subjects were divided into two groups, a retethered group, and a non-progression group, according to whether or not surgical interventions had been performed. Two consecutive EDSs, clinical findings, spine magnetic resonance imaging scans, and UDSs before the development of new tethering symptoms were reviewed and compared.

RESULTS

In the electromyography (EMG) study, the appearance of abnormal spontaneous activity (ASA) in new muscles was prominent in the retethered group (p < 0.01). The loss of ASA was more pronounced in the non-progression group (p < 0.01). Specificity and sensitivity of EMG for retethering were 80.4 and 56.5%, respectively. In the nerve conduction study, the two groups did not show differences. The size of fibrillation potential was not different between the groups.

CONCLUSIONS

To provide support for a clinician's decision on retethering, EDS could be an advantageous tool with high specificity when the results are compared to previous EDS results. Routine follow-up EDS post-operatively is recommended as a baseline for comparison at the time when retethering is clinically suspected.

Fibrofatty filum terminale: long-term outcomes from a Singapore children's hospital

OBJECTIVE

The role of prophylactic detethering a fibrofatty filum terminale (FFT) remains equivocal. Furthermore, long-term studies focusing on urological outcomes are sparse. The aims of this study were to present an institutional experience on the perioperative and long-term outcomes of FFT surgery and to assess for factors that contribute to postoperative clean intermittent catheterization (CIC).

METHODS

This was a single-institution, retrospective study conducted over a 20-year period. Patients younger than 19 years of age who underwent surgery for FFT were included. Variables of interest included patient demographics, clinical presentation, radiological findings, postoperative complications, and long-term need for CIC. Outcomes were measured using the Necker functional score and modified Hoffer Functional Ambulation scale score at 3, 6, and 12 months postdischarge.

RESULTS

A total of 164 surgeries were performed for FFT from 2000 to 2020. The median age at surgery was 1.1 years, and the mean follow-up duration was 8.3 years. There were 115 patients (70.1%) who underwent prophylactic-intent surgery and 49 patients (29.9%) who underwent therapeutic-intent surgery. The proportion of therapeutic-intent surgeries increased significantly with age percentiles (0-20th, 21.9%; 20th-40th, 9.1%; 40th-60th, 18.2%; 60th-80th, 36.4%; and 80th-100th, 63.6% [p < 0.001]). Thirty patients (18.3%) had an associated syndrome, the most common (n = 19, 11.6%) being VACTERL (vertebral defects, anal atresia, cardiac defects, tracheo-esophageal fistula, renal anomalies, and limb abnormalities). Forty-eight patients (29.3%) had an associated malformation (anorectal anomaly = 37, urogenital anomaly = 16, and sacral anomaly = 3). Cutaneous manifestation was the most common presentation (n = 96, 58.5%), followed by lower-limb neurological deficits (n = 21, 12.8%). A low-lying conus was present in 36.0% of patients (n = 59), and 16.5% had an associated syrinx (n = 27). There were 26 patients (18.8%) with an abnormal preoperative urodynamic study. Three patients (1.8%) had postoperative complications that required repeat surgery. There were no cases of CSF leakage. One patient (0.6%) developed retethering requiring another surgery. Postoperative CIC was required in 11 patients (6.7%). Multivariable analyses showed that an abnormal preoperative urodynamic study (adjusted OR 5.5 [95% CI 1.27-23.9], p = 0.023) and having an intraspinal syrinx (adjusted OR 5.29 [95% CI 1.06-26.4], p = 0.042) were associated with the need for CIC.

CONCLUSIONS

The authors' results demonstrate that detethering surgery for FFT is a relatively safe procedure and can be performed prophylactically. Nonetheless, the risks of postoperative CIC should be emphasized during the preoperative counseling process.

A Presenile Patient with Filar Lipoma Who Developed Tethered Spinal Cord Syndrome Triggered by Lumbar Canal Stenosis

Lumbar canal stenosis (LCS) has been reported as a precipitating factor by which a tethered spinal cord, which is asymptomatic during childhood, develops into tethered cord syndrome (TCS) in adulthood. However, only a few reports on surgical strategies for such cases are available. A 64-year-old woman presented with unbearable pain in the left buttock and dorsal aspect of the thigh approximately 1 year ago. Magnetic resonance imaging showed cord tethering with a filar-type spinal lipoma and LCS due to the thickening of the ligamentum flavum at the L4-5 vertebral level. Five months after the decompressive laminectomy for the treatment of LCS, an untethering surgery was performed at the dural cul-de-sac at the S4 level. The severed end of the filum was elevated rostrally by 7 mm, and the pain subsided postoperatively. This case study shows that surgeries for both lesions should be indicated for adult-onset TCS triggered by LCS.

Updates on Intraoperative Neurophysiology During Surgery for Spinal Dysraphism

Spinal dysraphism is a group of disorders resulting from an embryologic failure of spinal cord development which can lead to a radicular-medullary mechanical stretch that generates vascular compromise and hypoxic-ischemic damage to the nervous structures of the conus-cauda region.Thus, the clinical relevance of the different types of spinal dysraphism is related to the possible neurologic deficits resulting from spinal cord tethering. The clinical presentation is heterogenous: from asymptomatic to very compromised patients. The indications and the time of a detethering surgery are still subject of debate, although there is an agreement on the high standards of treatment that have to be offered by the surgery. Intraoperative neurophysiology (ION) contributes to the safety of tethered cord surgery in reducing the risks of iatrogenic neurological damages.

[Diagnosis and surgical treatment of tethered cord syndrome accompanied by congenital dermal sinus tract in adults]

OBJECTIVE

To summarize the clinical manifestations, imaging characteristics and experience of surgical treatment of tethered cord syndrome (TCS) accompanied by dermal sinus tract (DST) in adulthoods.

METHODS

The authors retrospectively analyzed a series of 25 adult patients with TCS due to DST that were surgically treated under microscope from September 2010 to October 2019. There were 10 males and 15 females with an average age of 29.7 years (rang, 18-48 years). Characterized cutaneous malformation and dermal sinus were found in the lumbosacral region in all the 25 patients. Clinically, all the patients presented with chronic back and lower-extremity pain, numbness and weakness of lower limbs, and bowel and bladder dysfunction. Two cases were admitted to the emergency room with acute infectious cerebral spinal fluid (CSF) leakage complicated with meningitis. According to magnetic resonance imaging (MRI) images, the subdural course of DST whose traction of the spinal cord, the location of the conus medullaris, the presence of subdural lesions, and the diameter of the internal filum terminale were evaluated. The surgical procedure included separating and excising of the DST, section of the internal filum terminale, detethering of the TCS, and reconstruction of the dural sac under microscopy. The patients remained in prone position in 7 days postoperation.

RESULTS

MRI showed that the position of the conus medullaris was lower than the level of lumbar 2 vertebrae, and the distal part of the DST entered the subdural stretched part of the spinal cord, to constitute one of the factors of TCS in all the 25 patients. Twenty patients had fatty infiltration of internal filum terminale and another patient had thickened (approximately 5 mm in diameter) internal filum terminale resulting in tightening the conus medullaris. A total of 25 operations were performed including completely dissection and resection of the DST through the skin down to the subdural space, section of the internal filum terminale, detethering of the TCS, and the subdural dermoid cysts were removed in two patients. There were no postoperative complications. The postoperative pathology was consistent with the structure of the DST and internal filum terminale. The local pain was relieved, and the lower-extremity weakness and bowel and bladder dysfunction were gradually relieved postoperatively. The period of follow-up ranged from 3 months to 9 years (mean, 3.9 years). The neurological function of all the patients was intact, and MRI showed that the physiological curvature of the thoracolumbar spine remained normal. There was no recurrence of TCS observed during the follow-up.

CONCLUSION

The adult TCS accompanied with DST is characterized by typical cutaneous malformation in the lumbosacral region and tethering of the spinal cord. The patients are usually combined with internal filum terminale enlargement tightening of conus medullaris as well. The surgical treatment including totally resection of the DST and section of the internal filum terminale to detethering the TCS at the same time under microscopy. The outcome of surgical treatment is satisfactory.

Does early tethered cord release in occult spinal dysraphism improve urological outcomes? A systematic review

Introduction

Occult spinal dysraphism involves a wide range of congenital anomalies, e.g., lipoma, Lipomeningomyelocele, congenital dermal sinus, etc. Occult spinal dysraphism also may present with a wide spectrum of clinical manifestations and radiological findings, i.e., it ranges from asymptomatic patients that are accidentally discovered to low lying conus with neurological, skeletal and urological manifestations. Even though neurosurgeons are well-aware of neurological presentations that indicate surgical intervention in children with occult spinal dysraphism, urological symptoms may present some controversy in management. This review aims to discuss urological outcomes of detethering as regarding time of intervention, improvement of the urological symptoms after detethering, and the role of urodynamics preoperatively and during follow-up.

Methodology

An online search of the literature was done including studies in English language from 1990 to January 2022. Included studies were analytical with well conducted descriptive nature of acceptable quality (at least level 3 evidence). Patient characteristics included both male and female children and adolescents, up to 19 years old who presented with clinical and/or radiological evidence of tethering of the spinal cord. Most studies that were included had availability of urodynamics. A total of 15 studies were included involving 633 patients. Meningomyelocele (MMC) and other spina bifida operta cases are excluded.

Results

Results of all studies were collected and mean age of studies was gathered and plotted on a chart in relation to urological outcome and urodynamic improvement. Most results favored early detethering; however, many factors were found to affect the inverse proportion curve of age with clinical improvement or urodynamics. For example, studies that included secondary tethered cord showed poorer results than results that included primary tethered cord only, preoperative severity of urological symptoms (more severe symptoms were associated with irreversible poor outcomes), and preoperative urodynamic parameters.

Conclusion

The management of tethered cord syndrome and occult spinal dysraphism remains controversial. There is lack of class 1 evidence regarding tethered cord release surgery in occult spinal dysraphism. Heterogenicity of pathology, symptomatology and radiology make the randomization of such sample size difficult. The outcomes of surgical detethering are therefore multifactorial. A large sample of prospective randomized controlled studies addressing each factor, e.g., age, severity of symptoms, preoperative urodynamic parameters, is recommended in order to evaluate the impact of each factor on outcome.

Spinal column shortening for tethered cord syndrome: a systematic review and individual patient data meta-analysis

OBJECTIVE

Tethered cord release (TCR) is the gold standard treatment for tethered cord syndrome (TCS); however, there are significant shortcomings including high rates of retethering, especially in complex and recurrent cases. Spinal column shortening (SCS) is an alternative treatment for TCS intended to avoid these shortcomings. Early studies were limited to case reports and smaller case series; however, in recent years, larger case series and small cohort studies have been conducted. Given the increase in available data, a repeat systematic review and meta-analysis is warranted to assess the safety and efficacy of SCS for TCS.

METHODS

The authors conducted a systematic review using MEDLINE (OVID), Embase (Elsevier), and Web of Science records dating from 1944 to July 2021 to identify all articles investigating SCS for TCS. They performed standard and individual patient data (IPD) meta-analyses, with 2 independent reviewers using PRISMA-IPD guidelines. Primary outcomes were improvement of preoperative clinical symptoms of pain, motor weakness, and bladder and bowel dysfunction, and also surgical complication rate. Secondary outcomes included urodynamic improvement and health-related quality-of-life outcomes determined using patient-reported outcome tools. Individual study quality assessment was performed using a standardized assessment tool for case reports/series, and publication bias was assessed using funnel plot analyses.

RESULTS

The review yielded 15 studies with 191 cases of TCS treated with SCS. IPD were available in 11 studies with 89 cases. The average age at time of surgery was 28.0 years (range 5-76 years). The average follow-up time was 33.2 months (range 7-132 months). Improvement was observed at last follow-up in 60 of 70 (85.7%) patients with preoperative pain, in 38 of 60 (60.3%) patients with preoperative weakness, and in 36 of 76 (47.4%) patients with preoperative bladder or bowel dysfunction. Complications of CSF leak, new neurological deficit, wound infection, or reoperation occurred in 4 of 89 (4.5%) patients.

CONCLUSIONS

SCS may be considered a safe and efficacious treatment option for TCS in children and adults (level C evidence; class IIb recommendation), especially for recurrent and complex cases. Current evidence is likely to be affected by selection and publication bias. Prospective comparative studies of SCS and TCR for TCS are recommended to determine long-term duration of outcomes, long-term safety in skeletally immature children, and exact indications of SCS versus traditional TCR.

Filum terminale transection in pediatric tethered cord syndrome: a single center, population-based, cohort study of 95 cases

Purpose

The purpose of this study was to evaluate outcome following surgical transection of filum terminale (FT) in symptomatic and asymptomatic pediatric patients with radiological findings consistent with tethered cord syndrome (TCS).

Methods

Patients < 17 years who underwent untethering surgery between 2007 and 2018 were screened for eligibility. Those who had undergone primary transection of the FT, and had preoperative radiological findings of fatty filum, thickened FT, or low-lying conus, below the pedicles of L2, were included. The cohort was divided into symptomatic and asymptomatic depending on clinical presentation. Surgical complications and functional outcome was recorded.

Results

In total, 95 patients were included, of whom 62 were symptomatic. In symptomatic patients, the main indications for radiological evaluation were scoliosis (29%) and motor symptoms (19%). In asymptomatic patients, skin stigmata (76%) were the most common finding. Fatty or thick FT was the most common radiographic finding, seen in 61% of symptomatic and 79% of asymptomatic cases. All patients underwent transection of the FT and were followed for a median of 1.8 years. A postoperative complication occurred in 12%, all Ibanez type Ib and managed without invasive treatment. For the symptomatic cohort, significant improvement was seen for both urodynamic assessment (48% improved, p = 0.002) and sensorimotor function (42% improved, p < 0.001).

Conclusions

Neurological improvement or halted deterioration was seen in the majority of symptomatic cases. Asymptomatic patients did not experience any severe complications. Filum transection should be offered to symptomatic and asymptomatic patients upon diagnosis of fatty filum, thickened FT, or low-lying conus.

Disorders of Secondary Neurulation: Suggestion of a New Classification According to Pathoembryogenesis

Recently, advanced knowledge on secondary neurulation and its application to the clinical experience have led to the deeper insight into the pathoembryogenesis of secondary neurulation with new classifications of the caudal spinal dysraphic entities. Here, we summarize the dynamic changes in the concepts of disordered secondary neurulation over the last two decades. In addition, we suggest our new pathoembryogenetic explanations for a few entities based on the literature and the data from our previous animal research. Disordered secondary neurulation at each phase may cause various corresponding lesions, such as (1) failed junction with the primary neural tube (junctional neural tube defect and segmental spinal dysgenesis), (2) dysgenesis or duplication of the caudal cell mass associated with disturbed activity of caudal mesenchymal tissue (caudal agenesis and caudal duplication syndrome), (3) abnormal continuity of medullary cord to the surrounding layers, namely, failed ingression of the primitive streak to the caudal cell mass (myelomeningocele), focal limited dorsal neurocutaneous nondisjunction (limited dorsal myeloschisis and congenital dermal sinus), and neuro-mesenchymal adhesion (lumbosacral lipomatous malformation), and (4) regression failure spectrum of the medullary cord (thickened filum and filar cyst, retained medullary cord and low-lying conus, terminal myelocele, and terminal myelocystocele). It seems that almost every anomalous entity of the primary neural tube may occur in the area of secondary neurulation. Furthermore, the close association of the caudal cell mass with the activity of caudal mesenchymal tissue involves a wider range of surrounding structures in secondary neurulation than in primary neurulation. Although the majority of the data are from animals and many theories are still conjectural, these changing concepts of normal and disordered secondary neurulation will provoke further advancements in our management strategies as well as in the pathoembryogenetic understanding of anomalous lesions in this area.

Mapping and monitoring of tethered cord and cauda equina surgeries

Surgery involving the cauda equina and tethered cord can be associated with significant functional disability including pain, motor and sensory deficits, as well as bladder, bowel, and sexual dysfunction. Neurophysiologic intraoperative monitoring and mapping during these surgeries using a variety of techniques and applications contributes to lessen the risk of permanent injury. This chapter reviews the anatomy of the pelvic floor, describes the techniques involved in monitoring and mapping this area, and describes the limitations of neurophysiology applications. Additionally, this chapter details mapping and monitoring techniques as they apply to tethered cord surgical release in both children and adults with review of outcome studies, and describes complications which can arise from tethered cord repair and injury to the cauda equina despite appropriate neurophysiologic intraoperative involvement.

Effect of untethering on occult tethered cord syndrome: a systematic review

BACKGROUND AND OBJECTIVES

Despite the evident clinical, neurological, orthopedic, and urodynamic dysfunctions, neuroanatomic imaging is normal in patients with occult tethered cord syndrome (OTCS). Therefore, the diagnosis of OTCS can be very complex. In this regard, this systematic review aimed to determine the main clinical features (i.e. neurological, musculoskeletal, and urological abnormalities) and improvement rates of these symptoms in patients with OTCS after the section of the filum terminale (SFT).

MATERIALS AND METHODS

All the papers published in three electronic databases, namely Google Scholar, PubMed, and Web of Science, were searched for the purposes of this study. The searching process started on 15 October and lasted until 9 November 2020. Eventually, 10 reports were found about the clinical outcomes of SFT for the management of the OTCS.

RESULTS

The included studies were carried out on a total of 234 patients with OTCS, all of whom had undergone SFT. Evaluation of urologic symptoms revealed that 40-100% of patients with OTCS suffered from urinary instability. Moreover, its improvement rate after SFT was estimated at 59-100%. Evaluation of neurological symptoms indicated that 25-69% of patients with OTCS suffered from back/leg pain, And its improvement rate, the symptoms of back/leg pain of all patients were resolved or improved after SFT. Lower extremity weakness was found in 9-40% of patients with OTCS which was resolved or improved after SFT in about 25-100% of patients. Nevertheless, surgical indications for occult tight filum terminale syndrome remain controversial.

CONCLUSION

Although it seems that the SFT in OTCS patients is promising in treating neurologic, orthopedic and urological symptoms, usage of surgical untethering for patients with OTCS is a controversial issue. Clinical evaluation and urodynamic testing can be used to identify patients with OTCS. However, a multidisciplinary diagnostic work-up is strongly recommended for every child with OTCS.

Dural splitting reconstruction in retethering after lipomeningocele repair: Technical note

Background:

Tethered spinal cord syndrome (TCS) can occur after the surgical repair of lipomeningoceles (LMCs). In these cases, the tethering results from postoperative adhesions between the spinal cord and the overlying repaired dura. A watertight dural closure using the residual dura and/or the surrounding tissues does not always provide enough space for the spinal cord and risks retethering. Here, we report a 16-year-old patient with secondary TCS following lipomeningocele repair who successfully underwent release of the tethered filum terminale utilizing a novel dural splitting reconstructive technique to attain a water-tight closure without the need for a duroplasty.

Methods:

A 16-year-old patient had a LMC repaired at birth. She now presented with progressive low back pain, and gait disturbances. The MRI documented secondary spinal cord tethering at the prior spinal dysraphism repair site.

Results:

A secondary release of the filum terminale utilizing a novel dural splitting technique to avoid the need for a duroplasty was performed.

Conclusion:

Here, in a 16-year-old patient with a recurrent tethered cord syndrome following repair of a LMC at birth, we utilized a novel dural splitting reconstruction technique and averted the need for a duroplasty.

Duroplasty in iatrogenic dorsal spinal cord herniation: illustrative case

BACKGROUND

The case report detailed an unusual presentation of an iatrogenic dorsal cord herniation at the level of the thoracic cord after insertion of an epidural catheter 8 months before presentation to the neurosurgical clinic.

OBSERVATIONS

Only 13 cases of iatrogenic dorsal cord herniation, most of which occurred after spinal surgery, have been described in the literature. This was the first case of a spinal cord hernia described after the insertion of an epidural catheter. In this case study, the authors described a 38-year-old man who presented with progressive lower limb weakness, sensory deficits, perianal numbness, and urinary/fecal incontinence. He was diagnosed with a spinal cord hernia that reherniated after an initial sandwich duroplasty repair. Definitive repair was made after his re-presentation using an expansile duroplasty.

LESSONS

In patients with previous spinal instrumentation who present with neurological symptoms, spinal cord herniation should be considered a likely differential despite its rarity. In this case, a simple duroplasty was insufficient to provide full resolution of symptoms and was associated with recurrence. Perhaps a combination of graft and expansile duroplasty may be used for repair, especially when associated with a tethered cord and in the presence of significant adhesions.

Tethered spinal cord among individuals with myelomeningocele: an analysis of the National Spina Bifida Patient Registry

OBJECTIVE

The aims of this study were to review the National Spina Bifida Patient Registry (NSBPR) data set to study the rates of tethered spinal cord release (TCR) among patients with myelomeningocele and variability between centers, to compare TCR rates between males and females, and to study the relationships between TCR rates and other condition-specific characteristics.

METHODS

The NSBPR registry was queried to identify all patients with myelomeningocele. TCR rates were calculated over time using survival analyses; rates between centers and between males and females were compared. Cox proportional hazards models were constructed to identify relationships between TCR rates and sex, functional lesion level, ambulation status, treated hydrocephalus, and prior Chiari decompression.

RESULTS

Of 6339 patients with information about their operations, 1366 (21.5%) underwent TCR, with significant variability between centers. The majority (75.8%) underwent a single TCR. The annual TCR rate was linear between birth and 13 years (1.8%/year) but declined sharply from 14 to 21 years (0.7%/year). There was no period of time at which the TCR rate accelerated. There were no significant differences in TCR rates between males and females. TCR rate was not related to functional lesion level but was lower among nonambulators compared with community ambulators (p = 0.005) and among those with treated hydrocephalus (HR 0.30, p < 0.001), and higher among those having prior Chiari decompression (HR 1.71, p < 0.001).

CONCLUSIONS

These results extend the results of prior single-institution studies, demonstrate significant treatment variability between institutions, and challenge the traditional concept that tethering is related to spinal cord stretching due to spinal growth.

Posterior Vertebral Column Subtraction Osteotomy for Recurrent Tethered Cord Syndrome: A Multicenter, Retrospective Analysis

BACKGROUND

Few have explored the safety and efficacy of posterior vertebral column subtraction osteotomy (PVCSO) to treat tethered cord syndrome (TCS).

OBJECTIVE

To evaluate surgical outcomes after PVCSO in adults with TCS caused by lipomyelomeningocele, who had undergone a previous detethering procedure(s) that ultimately failed.

METHODS

This is a multicenter, retrospective analysis of a prospectively collected cohort. Patients were prospectively enrolled and treated with PVCSO at 2 institutions between January 1, 2011 and December 31, 2018. Inclusion criteria were age ≥18 yr, TCS caused by lipomyelomeningocele, previous detethering surgery, and recurrent symptom progression of less than 2-yr duration. All patients undergoing surgery with a 1-yr minimum follow-up were evaluated.

RESULTS

A total of 20 patients (mean age: 36 yr; sex: 15F/5M) met inclusion criteria and were evaluated. At follow-up (mean: 23.3 ± 7.4 mo), symptomatic improvement/resolution was seen in 93% of patients with leg pain, 84% in back pain, 80% in sensory abnormalities, 80% in motor deficits, 55% in bowel incontinence, and 50% in urinary incontinence. Oswestry Disability Index improved from a preoperative mean of 57.7 to 36.6 at last follow-up (P < .01). Mean spinal column height reduction was 23.4 ± 2.7 mm. Four complications occurred: intraoperative durotomy (no reoperation), wound infection, instrumentation failure requiring revision, and new sensory abnormality.

CONCLUSION

This is the largest study to date assessing the safety and efficacy of PVCSO in adults with TCS caused by lipomyelomeningocele and prior failed detethering. We found PVCSO to be an excellent extradural approach that may afford definitive treatment in this particularly challenging population.

Disorders of Secondary Neurulation : Mainly Focused on Pathoembryogenesis

Recent advancements in basic research on the process of secondary neurulation and increased clinical experience with caudal spinal anomalies with associated abnormalities in the surrounding and distal structures shed light on further understanding of the pathoembryogenesis of the lesions and led to the new classification of these dysraphic entities. We summarized the changing concepts of lesions developed from the disordered secondary neurulation shown during the last decade. In addition, we suggested our new pathoembryogenetic explanations for a few entities based on the literature and the data from our previous animal research. Disordered secondary neurulation at each phase of development may cause corresponding lesions, such as failed junction with the primary neural tube (junctional neural tube defect and segmental spinal dysgenesis), dysgenesis or duplication of the caudal cell mass associated with disturbed activity of caudal mesenchymal tissue (caudal agenesis and caudal duplication syndrome), failed ingression of the primitive streak to the caudal cell mass (myelomeningocele), focal limited dorsal neuro-cutaneous nondisjunction (limited dorsal myeloschisis and congenital dermal sinus), neuro-mesenchymal adhesion (lumbosacral lipomatous malformation), and regression failure spectrum of the medullary cord (thickened filum and filar cyst, low-lying conus, retained medullary cord, terminal myelocele and terminal myelocystocele). It seems that almost every anomalous entity of the primary neural tube may occur in the area of secondary neurulation. Furthermore, the close association with the activity of caudal mesenchymal tissue in secondary neurulation involves a wider range of surrounding structures than in primary neurulation. Although the majority of the data are from animals, not from humans and many theories are still conjectural, these changing concepts of normal and disordered secondary neurulation will provoke further advancements in our management strategies as well as in the pathoembryogenetic understanding of anomalous lesions in this area.

Functional outcome after cord detethering in fecally incontinent patients with anorectal malformations

PURPOSE

Tethered cord (TC) occurs in 36% of patients with anorectal malformations (ARMs), for whom the benefit of detethering surgery remains unclear regarding bowel and/or bladder function. This study aimed to examine whether cord detethering could improve fecal and urinary incontinence in these patients.

METHODS

This was a retrospective study of TC patients (>3 years old) with fecal incontinence and ARMs, who underwent detethering surgery between 2016 and 2020 and were followed up for at least 6 months.

RESULTS

Of the 27 included patients, 55% had sacral ratios between 0.4 and 0.7, and in 37% it was < 0.4; the remaining 8% was over 0.7; 52% suffered from colonic hypermotility. After detethering surgery, partial fecal continence was achieved in five patients (18%); total fecal continence, in ten patients (37%); 12 (44%) remained fecally incontinent. Partial urinary continence was obtained in four cases (14%), and the number of patients with total urinary continence rose from 7 (25%) to 15 (55%). Lower extremity symptoms were also improved in 72% of the cases. Patients with colonic hypomotility were found to have a better functional outcome than those with colonic hypermotility (69% vs. 43%, respectively).

CONCLUSION

Our study demonstrated that detethering surgery led to remarkably improved bowel and bladder control in ARM patients with fecal incontinence, which, surprisingly, was not associated with sacral ratio.

Evaluation of Neurological Examination, SEP Results, MRI Results, and Lesion Levels in Patients Who Had Been Operated for Myelomeningocele

Objective:

Myelomeningocele is the most severe and the most frequent form of spina bifida. Most of the myelomeningocele patients undergo operations in new-born age. In terms of life quality and rehabilitation, follow-up’s of these patients in the growth and development period after the operation is critical. In our study, our aim is to emphasize the correlation of SEP results with MRI results and clinical features of the myelomeningocele patients.

Materials and Methods:

In our study, we included 36 patients who had undergone myelomeningocele operation and have been followed-up in Istanbul Bilim University Florence Nightingale Hospital, Spina Bifida Research and Treatment Centre. Posterior tibial nerve SEP was performed on each patient and neurological examinations were done in the same session. Results were compared with clinical functional lesion levels, levels of fusion defect and ambulation levels. In order to evaluate SEP results, we used age-related reference values from Boor et al.’s study in 2008. Patients were grouped as normal, unilaterally prolonged, bilaterally prolonged, unilaterally lost, and bilaterally lost.

Results:

The correlations of posterior tibial nerve SEP results were significant with ambulation levels (r = 0.428, P < 0.01), clinical functional lesion levels (r = 0.477, P < 0.01) and fusion defect levels (r = −0.528 P < 0.05). The lumbar SEP results were only significantly correlated with functional lesion levels (r = 0.443 P < 0.05).

Conclusions:

Radiological studies are insufficient when evaluating the functionality of the central nervous system. To fully evaluate the functionality and watch the neurological development with accuracy, especially in operated patients, electrophysiological studies should be an indispensable part of myelomeningocele follow-ups.

Outcome in 32 cases of tethered cord in adults-is intervention justified?

INTRODUCTION

Adults rarely present with tethered cord syndrome, and this review examines whether it is justifiable to perform surgical intervention in this group.

METHODS

Between 2003 and 2017, we performed surgical intervention in 32 adults with tethered cord syndrome. The age range varied from 22 to 65 years. Twenty-six had pain, 20 had motor deficits, and 18 had sensory deficits, whereas 17 presented with sphincter disturbances. Three had undergone surgery for meningomyelocele as infants. Six patients had major spinal deformity in the shape of kyphosis or scoliosis. All patients underwent digital radiographs and MR scans of the whole spine. The oldest with a leaking open meningocele was 41 years old.

RESULTS

The mean follow-up was 3.2 years. Twenty-one out of 26 patients presenting with pain had their VAS scores improve significantly; 14 had motor deficits which improved. However, sensory deficits got better in only 7 out of 18 patients, and sphincter improvement was documented (via urodynamics studies and bladder ultrasound) in only 4 out of 17 patients. In 15 cases, surgery was performed under neurophysiological monitoring, and overall improvement was documented in 11 of these patients compared with 7 of the remaining 17 patients. Surgery for spinal deformity was performed in 6 patients, and deformity correction as well as pain reduction was achieved in all.

CONCLUSION

Surgery leads to significant reduction of pain by untethering and in those with spinal deformity by correction of the same. Improvement in sensory changes and sphincter problems occurred in few patients. Neuromonitoring certainly has improved our results.

Tethered spinal cord related to caudal spinal dysraphism in a tailless Holstein calf

A rare dysraphic caudal spinal anomaly, or caudal agenesis, comprising a tethered spinal cord, was found in a tailless Holstein calf that presented ataxia and paresis with analgesia of the hind limbs. The gently and slimly tapered conus medullaris was poorly formed between S2 and S3 which indicated that it was lying more caudally. The caudal end of the filum terminale adhered to the inner periosteum of the vertebral arch at S4, which is compatible with tethering of the spinal cord. The dysraphic changes from the secondary neurulation error and the longitudinal deranged cord morphology that may have been caused by the caudad traction due to tethering were confirmed. This represents the first bovine case with definitive morphological confirmation.

Pediatric pathology all grown up - An interesting case of adult tethered spinal cord

Background:

Cervical myelopathy in an adult is typically the result of degenerative disease or trauma. Dysraphism is rarely the cause.

Case Description:

The authors report the case of a 35-year-old male drywall installer who presented with 2 years of progressive left upper extremity weakness, numbness, and hand clumsiness. Only upon detailed questioning did he mention that he had neck surgery just after birth, but he did not know what was done. He then also reported that he routinely shaved a patch of lower back hair, but denied bowel, bladder, or lower extremity dysfunction. Magnetic resonance imaging of the cervical spine demonstrated T2 hyperintensity at C4-C5 with dorsal projection of the neural elements into the subcutaneous tissues concerning for a retethered cervical myelomeningocele. Lumbar imaging revealed a diastematomyelia at L4. He underwent surgical intervention for detethering and repaired of the cervical myelomeningocele. Four months postoperatively, he had almost complete resolution of symptoms, and imaging showed a satisfactory detethering. The diastematomyelia remained asymptomatic and is being observed.

Conclusion:

Tethered cervical cord is a rare cause for myelopathy in the adult patient. In the symptomatic patient, surgical repair with detethering is indicated to prevent disease progression and often results in clinical improvement.

Tethered Cord Syndrome After Myelomeningocele Repair: A Literature Update

Tethered cord syndrome (TCS) after myelomeningocele (MMC) repair (or secondary TCS) is a challenging condition characterized by neurological, orthopedic, and urological symptoms, which are combined with a low-lying position of the conus medullaris and damage to the stretched spinal cord owing to metabolic and vascular derangements. It has been reported that this syndrome affects, on average, 30% of children with MMC. In this review, we revisit the historical aspects of secondary TCS and highlight the most important concepts of diagnosis, treatment, and outcomes for secondary TCS as well as the current research regarding the impact of fetal MMC repair in the incidence and management of TCS. In the future, the development of synthetic models of TCS could shorten the learning curve of pediatric neurosurgeons, and research into the cellular proapoptotic features and increased inflammation biomarkers associated with TCS will also improve the treatment of this condition and minimize retethering of the spinal cord.

Determining the optimal timing of screening spinal cord ultrasonography to detect filum terminale lipoma in infants

Purpose

The purpose of this study was to identify the optimal timing for screening spinal cord ultrasonography (US) to detect filum terminale lipoma in infants.

Methods

We retrospectively reviewed infants (<12 months old) who underwent repeated spinal cord US between April 2011 and January 2019. We excluded infants if they only had one US examination, or if they had lesions other than filum terminale lipoma. Infants with filum terminale lipoma on magnetic resonance imaging were included in the lipoma group and the others in the control group. A linear mixed model was used to assess differences in the growth pattern of filum terminale thickness by age and group. The cutoff thickness on US and its diagnostic performance were assessed according to age.

Results

Among 442 infants with 901 US examinations, 46 were included in the lipoma group and 58 in the control group. Sixty-seven infants had unmeasurable filum terminale thickness on initial US, including 55 neonates (82.1%) before 1 month of age. The lipoma group had significantly greater filum terminale thickness than the control group (P<0.001). Thickness increased with age in the lipoma group (P=0.027). The sensitivity of US was 87.5% and the area under the receiver operating characteristic curve was 0.949 (95% confidence interval, 0.849 to 0.991) with a cutoff value of 1.1 mm in 4- to 6-month-old infants.

Conclusion

Screening spinal cord US could effectively diagnose filum terminale lipoma in 4- to 6-month-old infants with a cutoff thickness of 1.1 mm. Spinal cord US can be used to screen young infants with intraspinal abnormalities.

Intraoperative Neurophysiology Monitoring for Spinal Dysraphism

Spinal dysraphism often causes neurological impairment from direct involvement of lesions or from cord tethering. The conus medullaris and lumbosacral roots are most vulnerable. Surgical intervention such as untethering surgery is indicated to minimize or prevent further neurological deficits. Because untethering surgery itself imposes risk of neural injury, intraoperative neurophysiological monitoring (IONM) is indicated to help surgeons to be guided during surgery and to improve functional outcome. Monitoring of electromyography (EMG), motor evoked potential, and bulbocavernosus reflex (BCR) is essential modalities in IONM for untethering. Sensory evoked potential can be also employed to further interpretation. In specific, free-running EMG and triggered EMG is of most utility to identify lumbosacral roots within the field of surgery and filum terminale or non-functioning cord can be also confirmed by absence of responses at higher intensity of stimulation. The sacral nervous system should be vigilantly monitored as pathophysiology of tethered cord syndrome affects the sacral function most and earliest. BCR monitoring can be readily applicable for sacral monitoring and has been shown to be useful for prediction of postoperative sacral dysfunction. Further research is guaranteed because current IONM methodology in spinal dysraphism is still deficient of quantitative and objective evaluation and fails to directly measure the sacral autonomic nervous system.

Occult tethered cord syndrome: a reversible cause of paraparesis not to be missed

A 15-year-old female former gymnast with a history of pectus excavatum was reviewed due to unexplained paraparesis and urinary incontinence since age 10. Symptoms were commenced with intolerable upper back pain and development of a soft mass at the sacrum that remitted spontaneously. Brain and whole spine MRI imaging and blood and CSF testing were normal. The combination of skeletal, neurological, and bladder symptoms with normal lumbar MRI and abnormal urodynamic and neurophysiological studies led to the clinical suspicion of occult tethered cord syndrome (oTCS). Surgical cord "untethering" was performed leading to remarkable postoperative clinical improvement. oTCS is a recently defined functional disorder of the spinal cord due to fixation (tethering) of the conus medullaris by inelastic elements that may lead to severe neurological impairment. High clinical suspicion is required as oTCS is a treatable spinal cord disorder.

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.

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.

The Filum disease and the Neuro-Cranio-vertebral syndrome: definition, clinical picture and imaging features

Background

We propose two new concepts, the Filum Disease (FD) and the Neuro-cranio-vertebral syndrome (NCVS), that group together conditions thus far considered idiopathic, such as Arnold-Chiari Syndrome Type I (ACSI), Idiopathic Syringomyelia (ISM), Idiopathic Scoliosis (IS), Basilar Impression (BI), Platybasia (PTB) Retroflexed Odontoid (RO) and Brainstem Kinking (BSK).

Method

We describe the symptomatology, the clinical course and the neurological signs of the new nosological entities as well as the changes visible on imaging studies in a series of 373 patients.

Results

Our series included 72% women with a mean age of 33.66 years; 48% of the patients had an interval from onset to diagnosis longer than 10 years and 64% had a progressive clinical course. The commonest symptoms were: headache 84%, lumbosacral pain 72%, cervical pain 72%, balance alteration 72% and paresthesias 70%. The commonest neurological signs were: altered deep tendon reflexes in upper extremities 86%, altered deep tendon reflexes in lower extremities 82%, altered plantar reflexes 73%, decreased grip strength 70%, altered sensibility to temperature 69%, altered abdominal reflexes 68%, positive Mingazzini’s test 66%, altered sensibility to touch 65% and deviation of the uvula and/or tongue 64%. The imaging features most often seen were: altered position of cerebellar tonsils 93%, low-lying Conus medullaris below the T12L1 disc 88%, idiopathic scoliosis 76%, multiple disc disease 72% and syringomyelic cavities 52%.

Conclusions

This is a paradigm shift that opens up new paths for research and broadens the range of therapeutics available to these patients.

Spinal Dysraphism in the Last Two Decades : What I Have Seen during the Era of Dynamic Advancement

Compared to any other decade, the last two decades have been the most dynamic period in terms of advances in the knowledge on spinal dysraphism. Among the several factors of rapid advancement, such as embryology during secondary neurulation and intraoperative neurophysiological monitoring, there is no doubt that Professor Dachling Pang stood high amidst the period. I review here the last two decades from my personal point of view on what has been achieved in the field of spinal dysraphism, focusing on occult tethered cord syndrome, lumbosacral lipomatous malformation, terminal myelocystocele, retained medullary cord, limited dorsal myeloschisis and junctional neural tube defect. There are still many issues to revise, add and extend. Profound knowledge of basic science is critical, as well as refined clinical analysis. I expect that young scholars who follow the footsteps of precedent giants will shed bright light on this topic in the future.

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.

Rare Cause of Acute Tetraplegia and Respiratory Arrest: Cervicomedullary Neuroenteric Cyst in a Child: Case Report

Background:

Neuroenteric cysts (NCs) are benign, rare congenital lesions which are most commonly found in the lower cervical and upper thoracic segments. Even though these are benign lesions, it may present with fatal neurologic deterioration particularly in pediatric patients.

Case Report:

We here report a 16-year-old boy who has unique manifestation with acute tetraplegia and respiratory arrest in emergency room. According to English literature, this is the first case of cervicomedullary intradural neuroenteric cyst which causes acute tetraplegia and respiratory arrest in a child.

Conclusion:

The NCs can be manifested with unpredictable, life threating clinical presentation. The exact pathophysiology of an acute neurological deterioration is still unclear, however prolonged latent period with minor symptom should be considered carefully in child population.

Conus Medullaris Levels on Ultrasonography in Term Newborns : Normal Levels and Dermatological Findings

Objective

Ultrasonography (US) is the most non-invasive, safe, and, especially in the period of infancy, best method for visualizing and examining the spinal cord. Furthermore, US is the primary work-up for development of the spinal canal, and for follow-up on issues relating to subcutaneous tissues, bone development, and the spinal cord. Conus medullaris terminates at the second lumbar vertebra, according to a consensus in the literature.

Methods

Healthy children under the age of 6 months who were admitted to the radiology clinic for routine USG follow-ups between the dates of March 2012 to December 2014 were included in this study.

Results

Our study includes data from 1125 lumbosacral ultrasounds. The terminal point of the conus level of the attended infants, superior, middle part, inferior of the vertebrae L1, L2, and L3. Furthermore, the termination of the discal distance ratio did not differ significantly between genders.

Conclusion

Therefore, according to our results, gender is not an influencing factor in the termination of the spinal cord. Based on the study we performed, as well as the previous literature, in infants without a recognized spinal pathology, the spinal cord is detected below the vertebra L3.

Caudal cell mass developmental aberrations: an imaging approach

The objective of this review is to describe antenatal and postnatal imaging criteria, which allow diagnosis and aid workup, prognostication and treatment of developmental anomalies of the caudal cell mass. The lower spinal cord (conus medullaris), filum terminale and inferior lumbar and sacral nerve roots develop from the caudal cell mass, a remnant of the embryologic primitive streak composed of undifferentiated pluripotential cells. Anomalous caudal cell mass development can manifest as tight filum terminale, caudal dysgenesis, terminal myelocystocele, anterior sacral meningocele or sacrococcygeal teratoma. Lower spinal cord development occurs simultaneously and in topological proximity to the developing lower gastrointestinal and genitourinary tracts, leading to coexistent malformations. We review the embryology of the caudal cell mass, describe the role of antenatal and postnatal imaging for diagnosing, staging, prognosticating and guiding intranatal or postnatal intervention for developmental anomalies of this region and briefly discuss clinical manifestations and treatment goals and strategies. An overview of antenatal imaging diagnosis of associated multisystem abnormalities will be provided where applicable.

Fatty filum terminale (FFT) as a secondary tethering element in children with closed spinal dysraphism

PURPOSE

The purpose of this study was to assess the prevalence of FFT as an additional tethering element in children operated for closed spinal dysraphism, where FFT was not the primary tethering pathology.

METHODS

This is a retrospective study of 195 children (< 18 years of age) who underwent surgery for closed spinal dysraphism and did not have FFT as the primary diagnosis. All patients were operated during the period 2005-2017 by a single surgeon. The commonest diagnosis was a lipomyelomeningocele (LMMC, n = 81, 41.5%), followed by split cord malformations (SCM, types I and II, n = 61, 31.3%), dermal sinus (n = 28, 14.4%), and dermoid cyst (n = 10, 5.1%). Factors such as age and sex, presenting symptoms, intraoperative findings, and radiological presence of a FFT on a magnetic resonance imaging (MRI) were documented, and the relationship between the primary diagnoses and presence of FFT was analyzed.

RESULTS

FFT as a secondary finding was seen in 63 patients (32.3%). The mean age of the cohort was 54 months (4.5 years) and the sex distribution was relatively even (51.8% girls). The commonest symptom at presentation was a swelling in the back, followed by lower limb weakness. The mean duration of symptoms was nearly 30 months. FFT was seen on the MRI and confirmed intraoperatively in 55 patients (28.2%). There were 8 patients (4.1%) where a FFT was seen intraoperatively, but was not diagnosed on the preoperative MRI. In 16 patients, FFT was seen > 2 segments away from the primary tethering pathology, 8 of which mandated a second skin incision for sectioning of the FFT. Secondary FFT was most commonly associated with a SCM (types I and II combined) and was seen in 42.6% of those patients. It was least commonly associated with intradural dermoid cysts.

CONCLUSION

The presence of a secondary FFT should be considered and actively sought on preoperative thin-slice T1W axial MR images in the sacral region in all patients with spinal dysraphism. Even if a FFT is not seen on preoperative MR images, the filum should be explored and sectioned if it is in the vicinity of the primary surgical field, especially in patients with SCM.

Adult Versus Pediatric Tethered Cord Syndrome: Clinicoradiological Differences and its Management

Background

Dysraphic lesions in adults, presenting clinically as tethered cord syndrome (TCS), are relatively rare, and their optimal management remains controversial.

Patients and Methods

We performed a retrospective analysis of our pediatric database over a period of last 7 years to focus on the adult TCS. Our aim was to determine the clinicoradiological and etiopathological differences between adult and pediatric patients as well as to determine the results of surgery in adult TCS.

Results

Adult spinal dysraphisms constituted 15.4% of our patients (20 out of 130). Motor weakness, sphincteric dysfunction, and backache (n = 13, 65.0% each) predominated in adults unlike children who presented with subcutaneous swellings (n = 74, 67.6%) followed by motor weakness (n = 40, 46.4%), backache being reported by only three patients. The different pathologic substrates underlying adult dysraphisms were lipomeningocele (n = 8), split cord malformation (total = 7; Type 1: n = 5; Type 2: n = 2), dermal sinus (n = 2), and fatty filum (n = 3). On the other hand, meningomyelocele/meningocele (61, 54.9%) followed by split cord malformation Type 1 and 2 (n = 29, 26.1%) predominated in children. The radiological differences between the two groups were a higher incidence of vertebral body defects (hemivertebrae and butterfly vertebrae) and lack of intracranial anomalies in adults. At a mean follow-up of 20.5 months, the most common symptoms to improve following detethering were pain (11 out of 13, 84.6%) followed by motor weakness (six out of 13, 56.2%) and sphincteric control (7 out of 13, 53.8%).

Conclusion

Most common symptoms to improve following detethering in adult TCS were pain followed by motor weakness. The major radiological differences between these two groups were a higher incidence of vertebral body defects (hemivertebrae and butterfly vertebrae) and lack of intracranial anomalies in adults.