Aberrant Dorsal Nerve Root as a Concomitant Cause of Spinal Cord Tethering Associated with a Dorsal Type Lipomyelomeningocele in a Child With Caudal Agenesis.

ABSTRACT: Tethered cord syndrome is a neurological disorder closely associated with congenital spinal dysraphism. Aberrant dorsal nerve roots may be one of the possible and relatively rare tethering pathologies, especially in the complex form of occult spinal dysraphism such as caudal regression syndrome or split cord malformation. We report an illustrative case of caudal regression syndrome with spinal cord tethering due to a combination of a contiguous bundle of an aberrant dorsal nerve root, and a dorsal-type lipomyelomeningocele, with a thickened filum terminale treated with microneurosurgical untethering.

Cauda Equina Arteriovenous Malformation with Bilateral Arterial Feeders.

Cauda equina arteriovenous malformation (AVM) is extremely rare. To our knowledge, only 2 cases have been reported previously and are supplied by a unilateral lateral sacral artery (LSA). Here, we report a rare cauda equina AVM at the level of L5-S1, which is supplied by the bilateral LSAs. Given the multiple feeders and complex angioarchitecture, endovascular embolization was performed with Onyx (ev3) successfully. The postoperative course of the patient was uneventful, and symptoms gradually improved. The present case demonstrated the angioarchitecture of the bilateral arterial supplies and venous drainage of the cauda equina AVMs. Cauda equina AVM with bilateral arterial feeders is extremely rare. However, clinicians should be aware of the possibility of this condition and the importance of selective spinal angiography of bilateral LSAs.

Tethered Cord Syndrome Caused by Duplicated Filum Terminale in an Adult with Split Cord Malformation.

BACKGROUND: Tethered cord syndrome (TCS) is a clinical diagnosis of progressive neurologic aggravation of the lower spinal cord due to a traction on the conus medullaris. Untethering surgery is effective for most TCS; however, when anatomic variations of spinal cord and filum terminale (FT) exist, regular untethering may lead to a failed outcome. CASE DESCRIPTION: The authors present the case of a 45-year-old patient with TCS caused by duplicated FT with split cord malformation (SCM). Lumbosacral magnetic resonance imaging revealed a type II SCM with a significant low-lying conus medullaris. Laminectomy was performed. Neurophysiologic monitoring was used for nerve root identification and 2 thickened fila, which failed to respond on stimulation, were found during the surgery. Both fila were sectioned, and the diagnosis was finally confirmed by pathologic examination. Postoperatively, the patient's symptoms disappeared immediately and no neurologic sequela was found after surgery. CONCLUSIONS: This is the first documented adult of duplicated FT with preoperative radiologic evidence and reported in association with SCM as a cause of TCS. When SCM exists, a careful observation for duplicated FT is warranted on preoperative magnetic resonance imaging and during surgery. Complete transection of the double FT under intraoperative neurophysiologic monitoring is the best treatment for this anomaly.

Tethered cord syndrome and transitional vertebrae.

PURPOSE: Tethered cord syndrome (TCS) usually presents with low-lying conus medullaris and thickened filum terminale. Spinal cord anomalies usually accompany congenital malformations and variations of the vertebral column. Transitional vertebrae (TV) are common variant, especially in the lumbosacral region. Accurate definition of the spine level is essential for proper radiological diagnosis and treatment. In this study, congenital spinal cord and vertebral anomalies and the relation with TV groups and types were evaluated in TCS patients. METHODS: The study was performed in 97 patients. Radiological imaging findings [computed tomography (CT), magnetic resonance imaging (MRI), and radiography] and medical records were evaluated. Spine bony malformation, spinal cord malformation, and spinal level of malformation were compared with TV and non-TV groups in TCS patients. In addition, TV groups and types were compared with each other for these anomalies. RESULTS: There was no statistically significant difference between TV and non-TV group in terms of the presence of vertebral bone and spinal cord anomalies. There were some significant differences in some of the spine bone and spinal cord anomalies among the groups and types of TV. CONCLUSION: Sixty-two point nine percent TCS patients had TV. Although these findings indicate that TV is common in patients with TCS, no significant difference is observed in most of the studied anomalies. However, there were some differences among the TV groups and TV types in relation to congenital malformations. It can be concluded that TV anomaly could be a distinct malformation apart from all the other anomalies that were studied. Transitional vertebrae may cause pain due to biomechanical changes in addition to progressive neurological symptoms which are usually seen with TCS.

The clinical significance of redundant nerve roots of the cauda equina in lumbar spinal stenosis patients: A systematic literature review and meta-analysis.

OBJECTIVES: Decompression surgery for lumbar spinal stenosis (LSS) is the most performed spine surgery procedure in patients older than 65 years. Around 40% of LSS patients scheduled for decompression surgery have evidence of redundant nerve roots (RNR) of the cauda equina on their magnetic resonance images (MRI). Little is known about the clinical significance of RNR in LSS patients. The objective was to assess the effects of RNR on clinical scores and recovery in older adults diagnosed with LSS. PATIENTS AND METHODS: A systematic literature search was performed in April 2018 on PubMed, Web of Science, MEDLINE and Cumulative Index to Nursing and Allied Health Literature (CINAHL). Prospective and retrospective cohort studies undertaken to assess differences in clinical outcomes in patients diagnosed with LSS with versus without evidence of RNR on their MRIs were selected. Two authors independently selected studies, abstracted data and assessed risk of bias. We calculated weighted mean differences (WMD) for continuous variables and odds ratio (OR) for variables reported in frequencies. RESULTS: Seven studies comprising a total of 1046 LSS patients were included in the meta-analysis. LSS patients with evidence of RNR (RNR+) were older, WMD 5.7 95% CI [2.2-9.2], p = 0.001, had smaller cross sectional area (CSA) of the stenotic level, WMD -12.2 95% CI [-17.7 to -6.7], p < 0.0001 and longer symptom onset duration, WMD 13.2 95% CI [-0.2-26.7], p = 0.05. The pooled preoperative clinical score in the RNR + group was worse but the difference was not statistically significant, WMD -3.8 95% CI [-7.9 to 0.2], p = 0.07. After decompression surgery RNR + patients had worse clinical scores, -4.7 95% CI [-7.3 to -2.1], p = 0.0004 and lower recovery rates, -9.8 95% CI [-14.8 to -4.7], p = 0.0001. CONCLUSION: There is limited quality evidence that RNR + patients are older, have a longer symptom history and present higher degrees of lumbar stenosis as given by the narrow CSA in comparison to RNR- patients. After decompression surgery RNR + patients have worse clinical scores and lower recovery rates. In view of these results RNR can be seen as a negative prognostic factor in LSS patients.

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.

Duplicated filum terminale in non-split cord malformations: An underrecognized cause for treatment failure in tethered cord syndrome.

CONTEXT: Anatomical variations of the filum terminale (FT) have been described in association with split cord malformations (SCM) but they appear to be a rare finding in its absence. We report the first case in literature of a duplicated FT in a patient presenting with tethered cord syndrome (TCS) without any radiological evidence of SCM. FINDINGS: A 47-year-old man presented with invalidating back pain radiating to both legs. Magnetic resonance imaging revealed an intradural dorsal lipoma in a low-lying conus. Intraoperatively two distinct fibrous bands were anatomically and electrophysiologically identified as the FT and both were sectioned. The diagnosis of FT was confirmed for both specimens by histology. CONCLUSION: In absence of SCM, a duplicated FT has not been previously described as a cause of TCS. It may be a cause of treatment failure for TCS if unrecognized on preoperative imaging and during surgery if one filum remains intact. We highlight the importance of a meticulous cauda equina dissection supported by intraoperative nerve stimulation to identify this rare anomaly. We hypothesize that this entity may represent a variant of SCM involving the caudal neural tube but which requires further validation at an embryological level.

Functional variability of sacral roots in bladder control.

OBJECT: Sacral roots are involved in sensory, autonomic, and motor innervation of the lower limbs and perineum. Theoretically, it can be assumed that the S-3 root level innervates the bladder; however, clinical practice shows that this distribution can vary. Few researchers have studied this variability. METHODS: The authors conducted a retrospective study involving 40 patients who underwent surgery requiring an electrophysiological exploration of the sacral roots. They performed stimulations for the monitoring of muscular (3 Hz, 1 V) and bladder responses under cystomanometry (30 Hz, 10 V). RESULTS: Although the S-3 roots were involved in bladder innervation in all cases, they were exclusively involved (i.e., the only nerve roots involved) in only 8 of 40 cases. In the remaining 32 cases, other sacral nerve roots were involved. The most common association was S-3+S-4 (12 cases), followed by S-2+S-3 (6 cases), S-2+S-3+S-4 (5 cases), and S-3+S-4+S-5 (2 cases). Stimulation of S-2 could sometimes induce bladder contraction (15 cases, 40%); however, the amplitude was often low. S-4 nerve roots were involved in 24 of 40 cases (60%) in the bladder motor function, whereas S-5 roots were only involved 7 times (17%). Occasionally, we noticed a horizontal asymmetry in the response, with a predominant response from the right side in 6 of 7 cases, always with a major S-3 response. CONCLUSIONS: This is the first study showing a significant horizontal and vertical variability in the functional distribution of sacral roots in bladder innervation. These results show the variability of cauda equina syndromes and their forensic implications. These data should help with the monitoring of sacral roots and the performance of several tasks during surgery, including neurostimulation and neuromodulation.

Birth defects associated with perturbations in preimplantation, gastrulation, and axis extension: from conjoined twinning to caudal dysgenesis.

Congenital malformations represent approximately 3 in 100 live births within the human population. Understanding their pathogenesis and ultimately formulating effective treatments are underpinned by knowledge of the events and factors that regulate normal embryonic development. Studies in model organisms, primarily in the mouse, the most prominent genetically tractable mammalian model, have equipped us with a rudimentary understanding of mammalian development from early lineage commitment to morphogenetic processes. In this way, information provided by studies in the mouse can, in some cases, be used to draw parallels with other mammals, including human. Here, we provide an overview of our current understanding of the general sequence of developmental events from early cell cleavages to gastrulation and axis extension occurring in human embryos. We will also review some of the rare birth defects occurring at these stages, in particular those resulting in conjoined twinning or caudal dysgenesis.

"Horseshoe cord terminus" sans filum around a bone spur: a rare composite of faulty gastrulation with agenesis of secondary neurulation: case report.

Split cord malformation (SCM) is classified based on the presence of a bone spur and double dural sac. The authors report on a 6-year-old child with primary enuresis in whom MRI findings were suggestive of Type I SCM, and who had unique intraoperative findings of a horseshoe-shaped split cord terminus anchored by a bone spur without the normally tapering conus and filum. The typical appearance of cauda equina was absent, with all the roots arising from the horseshoe cord terminus. This composite anomaly is probably due to the rare combination of faulty gastrulation with abnormal persistence of endomesenchymal tract causing SCM, with concurrent agenesis of secondary neurulation in turn causing absence of filum.

Multiple spinal cavernous malformations in Klippel-Trenaunay-Weber syndrome.

Klippel-Trenaunay-Weber syndrome (KTWS) is a rare, congenital vascular disorder characterized by cutaneous haemangiomas, venous varicosities, and hypertrophy of the osseous and soft tissue. Various vascular anomalies of the central nervous system have been described in this syndrome. Two previous associations between KTWS and spinal cord cavernous malformations have been reported in the English literature. In this report, we present a patient in whom multiple cavernous malformations located in the conus medullaris region and cauda equina were associated with KTWS. General physical examination as well as neuroradiological and operative findings are described.

Sirenomelia: four further cases with discussion of associated upper limb defects.

Sirenomelia, also known as the 'mermaid malformation/syndrome', is a rare, serious congenital anomaly characterized by variable degrees of fusion of the lower limbs and associated severe malformations of the lower vertebral and genitourinary systems. In this report, we describe a series of African patients with sirenomelia. We present the clinical and radiological features of four black South African patients and illustrate some of the rarer associated abnormalities, which include asymmetrical upper limb defects, not confined to the radial ray. The clinical phenotypic overlap between caudal dysgenesis, VACTERL association and sirenomelia in our patients is highlighted, lending support to the theory that these entities may be different manifestations of a single pathogenic process.

Sirenomelia and caudal malformations in two families.

We report on two families with co-occurrence of sirenomelia and caudal malformations. In the first family, the mother had undergone surgery for a short form of imperforate anus. Her first pregnancy was terminated because of bilateral renal agenesis with oligohydramnios. Her second pregnancy was interrupted because of sirenomelia. The second family was referred to us because of caudal malformation in their two children. The parents' spinal radiographs were normal. The first pregnancy resulted in a girl with imperforate anus, absence of S3-S5 and coccyx, abnormal pelvic floor, and an almost bifid anteriorly located bladder. The second pregnancy resulted in a baby girl with sirenomelia. No diabetes was present during the pregnancies in either of these two families. These families confirm the hypothesis that major genes are responsible for the embryogenesis of the caudal part of the embryo, with variable expression, as has been already described in sirenomelia mouse models (CYP26A1, BMP7/tsg). Molecular studies are underway in these families and in sporadic cases in our laboratory to explore the genetic basis of sirenomelia in humans.

Ultrasonography reveals a high prevalence of lower spinal dysraphism in children with urogenital anomalies.

BACKGROUND: Lower spinal dysraphism is frequently reported in anorectal anomaly combined with urogenital anomalies. The prevalence of the spinal dysraphism has not been comprehensively studied in children with simple urogenital anomalies. We evaluated the prevalence of the spinal dysraphism using ultrasound data of the lumbosacral area in children with urogenital anomalies. METHODS: Lumbosacral ultrasound images of 259 children who underwent urological surgery with simple urogenital anomalies were reviewed by an ultrasound-specialized radiologist. The primary outcome measures were the conus medullaris (CM) level and the thickness of the filum terminale. The spinal ultrasonographic findings that were assessed in children showed abnormal spinal findings compared with the other children having normal findings. Two years later, the follow-up telephone interviews were made with the parents of the children with abnormal findings. RESULTS: Eighteen children were differentiated as the abnormal finding group. They were suspected of spinal cord tethering. The level of CM was lower, and the filum terminale was thicker compared to the normal group [L2(lower (L)) vs. L1(L), 2.2 mm vs. 0.8 mm]. Of eighteen children, four were confirmed as tethered spinal cord with lipoma on magnetic resonance imaging by the time of surgery, and two were strongly suspected of occult spinal dysraphism (OSD) based on ultrasound findings and follow-up interviews. CONCLUSIONS: The prevalence of OSD in children under 24 months of age with simple urogenital anomaly was higher than what was reported for the general population. Ultrasound examination of spinal structures before caudal block in children with urogenital anomaly should be considered.

Deciphering caudal embryonic defects: embryological analysis and reviewing literature data.

BACKGROUND: A number of syndromes÷associations involving the caudal region have been described in the literature. Each of them is characterized by a set of morphological features. Reports on difficulties in delineation and an ever-increasing constellation of defects in recent past call for a comprehensive study into the morphologic presentations and pathogenesis of caudal embryonic defects. MATERIALS AND METHODS: The present article describes a case of the OEIS complex--a combination of omphalocele, exstrophy of bladder, imperforate anus and spinal defects. Literature search was performed and morphologic presentations, as described in literature, of all syndromes and associations affecting the caudal region of the embryo have been compared. Morphologic presentations were analyzed embryologically. RESULTS: A remarkable overlap of symptom complex was observed. Embryological analysis of the phenotypic presentations of all these syndromes points towards a common pathogenesis, early in the embryonic life. The embryologic analysis suggests that these defects are a result of defects in proliferation, migration or subsequent differentiation of any of the three subdivisions of intra-embryonic mesoderm. CONCLUSIONS: Based on the analysis a new hypothesis for the causation of caudal defects is proposed. This hypothesis suggests that a local internal environmental imbalance, at the site of implantation, can cause nutritional insult to the embryo during gastrulation, during the third and the early fourth week of embryonic life.