Split cord malformation in adults: Literature review and classification

Safety of Traditional Growing Rods in Patients with Early-Onset Congenital Scoliosis Associated with Type-I Split Cord Malformation

BACKGROUND

Literature regarding the application of traditional growing rod (TGR) instrumentation in patients with early-onset congenital scoliosis with type-I split cord malformation is scarce. The purpose of the present study was to assess the safety and effectiveness of TGR surgery and repeated lengthening procedures in patients with congenital scoliosis with type-I split cord malformation not treated with prophylactic osseous spur excision.

METHODS

Thirteen patients with early-onset congenital scoliosis associated with type-I split cord malformation and a stable neurologic status between March 2009 and July 2020 were recruited. All patients underwent primary TGR surgery and subsequent repeated lengthening procedures without osseous spur excision by the same surgical team. Clinical information and radiographic data from the preoperative, postoperative, and latest follow-up periods were collected.

RESULTS

The mean preoperative Cobb angle of the major coronal curve was 74.62° ± 25.59°, the mean early postoperative angle was 40.23° ± 17.89°, and the mean latest follow-up angle was 40.62° ± 16.60°. The scoliotic deformity correction percentage was 46.81% ± 12.26% after the initial operation and 45.08% ± 15.53% at the latest follow-up. Compared with the preoperative values, significant improvements were observed in the coronal and sagittal balance early postoperatively and at the latest follow-up (p < 0.05 for all). The average annual amounts of spinal height gained were 15.73 ± 5.95 mm at T1-S1, 8.94 ± 3.94 mm at T1-T12, and 12.02 ± 6.70 mm between the instrumented segments. The total height gained at T1-S1 and T1-T12 was 72.18 ± 28.74 mm and 37.62 ± 12.53 mm, respectively. No intraoperative neurophysiological monitoring events were observed, and no case of neurological deficit was observed postoperatively or during follow-up.

CONCLUSIONS

Patients without neurologic deficit and having a stable neurologic exam who have early-onset congenital scoliosis associated with type-I split cord malformation can safely and effectively undergo TGR surgery, followed by repeated lengthening procedures, without prophylactic osseous spur excision.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

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.

Developmental Abnormalities of the Pediatric Spine: A Review of the Correlation Between Ultrasound and MRI Findings

A broad spectrum of spinal pathologies can affect the pediatric population. Ultrasound (US) is the primary modality for pediatric spine assessment due to its widespread availability, non-requirement of sedation, and absence of ionizing radiation. Supplementing this, MRI offers an in-depth exploration of these conditions, aiding in preoperative strategizing. In this review, we examine the clinical indications, methodologies, and protocols for US and MRI scans of the pediatric spine. Additionally, we illustrate normal pediatric spinal anatomy, highlighting several examples of normal variants that are often misinterpreted. Through a series of case-based illustrations, we offer a comprehensive overview of various pathological conditions such as tethered cord, spinal dysraphism, spinal lipoma, diastematomyelia, and dermal sinus tract, among others. Furthermore, we explore the correlation between US and MRI findings for these lesions, employing real-world cases to enhance our understanding of this topic.

A Case of Neonate with Split Cord Malformation Presenting with Hypoplasia of the Left Lower Extremity

The frequency of split cord malformation (SCM) is approximately 1 in 5000 births; however, patients are rarely diagnosed with SCM in the neonatal period. Moreover, there have been no reports of SCM with hypoplasia of the lower extremities at birth. A 3-day-old girl was transferred to our hospital for a thorough examination of hypoplasia of the left lower extremity and lumbosacral abnormalities detected after birth. The spinal magnetic resonance imaging (MRI) revealed a split spinal cord in a single dural tube. Based on the MRI findings, the patient was diagnosed with SCM type II. Following discussions with the parents, pediatricians, neurosurgeons, psychologists, and social workers, we decided to perform untethering to prevent further neurological impairment after achieving a sufficient body weight. The patient was discharged on day 25 of life. Early diagnosis and intervention may improve the neurological prognosis in terms of motor function, bladder and bowel function, and superficial sensation; thus, clinicians should report infrequent findings that may lead to SCM diagnosis. SCM should be differentiated in patients with left-right differences in the appearance of the lower extremity, particularly in those with lumbosacral abnormalities.

Ischemic myelomalacia and closed spinal dysraphism in multiple finishing swine

Ischemic myelomalacia secondary to fibrocartilaginous emboli (FCE) is an idiopathic disease in humans and animals. On the other hand, congenital spinal cord malformations result from neural tube defects in fetal development (ie, spinal dysraphism), with structural anomalies referred to collectively as myelodysplasia. Spinal dysraphisms are frequently accompanied by skin and vertebral abnormalities because of the embryogenic relationship. In this observational case study, we report the pathologic findings of 13, 18- to 24-weeks-old pigs from a large conventional operation that presented with acute paraparesis. Ischemic myelomalacia secondary to FCE was observed in 5 of 13 examined pigs. Congenital spinal cord malformations located between the caudal thoracic and sacral spinal cord were identified in 7 pigs, with structural abnormalities that ranged from diplomyelia/split cord malformation to segmental spinal dysgenesis (myelodysplasia) to caudal agenesis. Concurrent myelomalacia and congenital spinal cord malformations in the same or different sites were noted in 2 pigs. No spinal lesion was observed in 3 pigs. Although gross vertebral abnormalities were not observed herein, intervertebral instability due to minor defects in the articular facets, as well as other unidentified factors, is suspected to contribute high incidence of FCE. It is likely that these congenital malformations were previously underdiagnosed or are possibly new conditions associated with continuous inbreeding and genetic improvement in the modern swine industry.

Thoracolumbar surgery for degenerative spine diseases complicated with tethered cord syndrome: A case report

BACKGROUND

Tethered cord syndrome (TCS) secondary to split cord malformation (SCM) is rare in adulthood. There is as yet no consensus about the optimal treatment method for adult patients with SCMs and degenerative spine diseases such as lumbar stenosis, spondylolisthesis and ossification of the ligamentum flavum (OLF). The tethered cord poses a great challenge to the decompression and fusion procedures for the intraoperative stretching of the spinal cord, which might lead to deteriorated neural deficits. Here, we report on a case to add our treatment experience to the medical literature.

CASE SUMMARY

We treated a 67-year-old female patient with type II SCM suffering from lumbar disc herniation, degenerative lumbar spondylolisthesis and thoracic OLF. The patient underwent thoracolumbar spinal fusion and decompression surgery for severe lower back pain, extensive left lower limb muscle weakness and intermittent claudication. After the thoracolumbar surgery, without stretching the tethered cord, the patient achieved complete relief of pain and lower extremity weakness at final follow-up.

CONCLUSION

For adult patients with underlying TCS secondary to SCM coupled with thoracic OLF and lumbar spondylolisthesis, a thoracolumbar fusion surgery could be safe and effective with the tethered cord untreated. It is critical to design individualized surgical protocols to reduce the stretch of the low-lying spinal cord.

Multiple-site neural tube defects complicated by multiple-site split cord malformations and thickened filum terminale: experience at a pediatric neurosurgical teaching hospital in Ethiopia. Illustrative case

BACKGROUND

Multiple-site open neural tube defects (MNTDs) and multiple-site split cord malformations (MSCMs) are extremely rare congenital anomalies that are defined by the simultaneous noncontiguous occurrence of more than one neural tube defect (NTD) and split cord malformation (SCM), respectively, in a single case with normal neural tissue in between. This work shows the cooccurrence of MNTDs and MSCMs, which has never been reported in the literature.

OBSERVATIONS

A single-stage repair for a 13-day-old female neonate with a preoperative diagnosis of MNTDs (thoracic meningocele and thoracolumbar myelomeningocele) plus an additional intraoperative diagnosis of MSCMs (type 3c) of thoracic and thoracolumbar spine, and thickened filum terminale was done with a favorable smooth postoperative course.

LESSONS

The use of intraoperative meticulous surgical technique along with preoperative skin stigmata helped for anticipation, detection, and treatment of associated complex spinal MNTDs, especially in resource-limited settings, where preoperative magnetic resonance imaging is not routinely used. Whether to repair the MNTDs as a single- versus multiple-stage procedure is mainly a function of the patient's tolerance to the duration of anesthesia and the anticipated blood loss for the patient's age. The overall developmental biology and long-term clinical outcome of MNTDs compared to single NTD/SCM is poorly understood and needs further study.

An Unusual Case of Torticollis: Split Cord Malformation with Vertebral Fusion Anomaly: A Case Report and a Review of the Literature

We describe the exceptional case of spinal cord malformation, associating neurenteric cyst, and cervical vertebral malformation, initially presenting as torticollis. A 4-month-old child presented with torticollis to the right since birth. A cervical spine X-ray revealed suspicious findings of fusion anomaly, and a cervical spine CT showed extensive segmentation-fusion anomaly with an anterior and posterior bony defect in the C1–6 vertebrae. A cervical spine MRI revealed extensive segmentation-fusion anomaly with an anterior bony defect, and the spinal cord split forward and backward at the C3 level, showing two hemicords. The anterior half of the hemicord and dural sac extended to the right inferior side, towards the upper blind end of esophageal duplication, and the posterior half joined the hemicord at the back and C6 level. After multidisciplinary collaboration, follow-up and conservative treatment were planned. At 12 months, he had developmental delay, and torticollis showed little improvement. No neurological abnormalities have been observed. The patient plans to undergo surgery for the cervical spine fusion anomaly. Cervical spine X-rays should always be performed when assessing a patient with torticollis to rule out cervical vertebral segmentation anomalies, despite the rarity of the condition.

Sacral Spina Bifida Occulta: A Frequency Analysis of Secular Change

Substantial relaxation of natural selection beginning around 1900 changed the mutation/selec­tion balance of modern genetic material, producing an increase in variable anatomical structures. While multiple structures have been affected, the temporal increase in variations of the sacrum, specifically, ‘Sa­cral Spina Bifida Occulta,’ have been reliably demonstrated on a localised scale. Calculation of largescale frequency has been hindered by the localised nature of these publications, the morphological variability of this variation, and potential pathological associations, which have produced divergent classifications, and conflicting reported rates of occurrence. A systematic review of the reported literature was conducted to provide an objective analysis of Sacral Spina Bifida Occulta frequency from 2500 BCE to the present. This review was designed to compensate for observed inconsistencies in reporting and to ascertain, for the first time, the temporal trajectory of this secular trend. A systematic review of Sacral Spina Bifida Occulta lit­erature was conducted through the strict use of clinical meta-analysis criteria. Publications were retrieved from four databases: PubMed, Embase, the Adelaide University Library database, and Google Scholar. Data were separated into three historical groups, (1 = <1900, 2 = 1900 to 1980 and 3 = >1980), and frequency outcomes compared, to determine temporal rates of occurrence. A total of 39/409 publications were included in the final analysis, representing data for 16,167 sacra, spanning a period of 4,500 years. Statistically significant results were obtained, with total open S1 frequen­cy increasing from 2.34%, (79 to 1900CE), to 4.80%, (1900 to 1980CE) and to 5.43% (>1980CE). These increases were significant at p<0.0001, with Chi-squared analysis. A clear secular increase in the global frequency of Sacral Spina Bifida Occulta has been demonstrated from 1900 to the present. This research provides a novel and adaptable framework for the future assessment of variation distribution, with impor­tant implications for the fields of biological anthropology and bioarchaeology.

MRI Characteristics of Split Cord Malformation

Split cord malformation (SCM), a subtype of spinal dysraphism, represents a rare entity of congenital malformation in the spine that occurs rarely in adults. SCM commonly presents with back pain. MRI is the gold standard for diagnosis. We report a case of a previously healthy 25-year-old woman who presented with lower back pain for a duration of 6 months. MRI confirmed a diagnosis of type I SCM. This case highlights the neuroimaging characteristics of SCM, although it might remain asymptomatic for many years. Surgical intervention might not be indicated in case of absent clinical complications.

Adult-onset presentation of cervicothoracic split cord malformation: illustrative case

BACKGROUND

A 60-year-old female presented with a 6-month history of progressive lower limb pain, weakness, and declining mobility. She was initially diagnosed as having possible hip osteoarthritis or ligamental knee injury. She was eventually seen by a neurologist, who admitted her to a tertiary hospital with new-onset upper motor neuron signs and urinary incontinence. Magnetic resonance imaging of the whole spine revealed evidence of C7–T2 type 1 split cord malformation (SCM) necessitating urgent spinal surgery. She had an excellent outcome with intensive rehabilitation and returned to her premorbid level of function and mobility.

OBSERVATIONS

The patient presented with nonspecific symptoms, which led to multiple referrals and a significant delay in her diagnosis.

LESSONS

Clinicians should be aware of the importance of a detailed history with thorough neurological and spinal examinations.

Epidural Placement in a Patient With a Type 2 Split Cord Malformation in the Interventional Pain Management Setting: A Case Report

Split cord malformations are rare spinal dysraphisms in which 2 separate spinal cords are present. Despite its diagnosis in all age groups, split cord malformations are not well described. The clinical presentation and symptom severity are highly variable. Anesthesiologists may encounter patients with known or unknown split cord malformations without much information to guide clinical decision-making and procedural risks of neuraxial anesthesia. This is the first case to the authors' knowledge of utilizing a caudal epidural injection for pain management in a patient with a diagnosed split cord malformation.

Split cord malformation and tethered cord syndrome: case series with long-term follow-up and literature review

PURPOSE

To date, the description of the natural course of concurrent tethered cord syndrome with a low-lying conus medullaris and split cord malformation is lacking in the literature. We report a cohort of adult and pediatric patients with concurrent malformations and long-term follow-up.

METHODS

Patients with concurrent diagnoses of split cord malformation and tethered cord (radiographic evidence supporting clinical symptomatology) were identified between 2000 and 2020. Patients without sufficient documentation or at least 6-month follow-up were excluded.

RESULTS

Nine patients were identified with an average of 8.9 years follow-up (range 2-31 years). The most common symptoms were radiating leg pain and lower extremity paresthesias, occurring in 44% of patients; and bladder/bowel dysfunction, worsening scoliosis, and acute motor deterioration were less common. Two patients were successfully treated conservatively for mild leg pain and paresthesias. For those who underwent surgery, all experienced symptomatic relief upon first follow-up. Two had late symptomatic recurrence; one 4 and 8 years after initial surgery; and the other, 11, 26, and 31 years after initial surgery.

CONCLUSION

The rarity of concurrent split cord and tethered cord syndrome with a low-lying conus makes management difficult to formulate. This series supplements our knowledge of the long-term outcomes and lessons learned from the management of these patients. Approximately 25% of patients were managed conservatively and had symptomatic improvement. For surgically managed patients, with intractable pain or worsening neurological function, symptoms can still recur over a decade after intervention. Reoperation, however, can still be beneficial, can provide years of relief, and should be considered.

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.