Split Cord Malformation Research Articles

Pre-operative clinical deterioration and long-term surgical outcomes in 41 patients with split cord malformation type 1.

To document the pre-operative rate of clinical deterioration in a cohort of patients with split cord malformation type 1 (SCM 1) and the early- and long-term surgical outcome in these patients. Data from 41 patients with SCM 1 operated upon by the same surgeon (VR) between January 2008 to June 2023 were retrospectively reviewed with respect to history of clinical deterioration prior to surgery and early and long-term surgical outcomes. The mean age of the patients at presentation was 79.3months and the male to female ratio was 1:1.93. Twelve (29%) patients had congenital deficits whereas 4 (10%) patients had no neurological deficits. Twenty-six (63%) patients had kyphoscoliosis and 25 (61%) patients had motor dysfunction. Thirty-three (81%) patients (8/12 (67%) with congenital deficits) had clinical deterioration prior to surgery. By the age of 2years, 56% of patients had clinical deterioration. After surgery, 18 (55%) patients with progressive symptoms had improvement in one or more of their symptoms on long-term follow-up (mean, 63.4months). There were no predictors of surgical outcome. Since over half of our patients with SCM 1 developed progression of congenital deficits or developed deficits by the age of 2years, surgery should be performed as soon as possible in these children. On long-term follow-up after surgery, improvement can be expected in over half the patients.

Unusual cause of incomplete cauda equina syndrome: dermoid cyst with a split cord malformation case report

Cauda equina syndrome is a surgical emergency caused by the compression of the lumbosacral nerves. The most frequent cause is discal herniation, while tumoral pathology in this region is rare, and congenital processes are less common. We report the case of a young 37-year-old male patient, admitted to the emergency room with an incomplete cauda equina syndrome. As medical history, a lumbar surgery 15 years ago was reported with no documentation. An MRI was performed, revealing a mass within the filum terminal exhibiting three components suggestive of a dermoid cyst accompanying a split cord malformation, which was confirmed by pathology. Various disorders may be associated to intradural dermoid cyst, such as lipoma, low-lying cord, hydromyelia or thick filum. Surgery is the treatment of choice, and MRI plays a crucial role in detecting associated abnormalities and determining surgery priorities.

Management of split cord malformation and tethered cord syndrome: Experience of a main referral center in Uzbekistan

BackgroundSplit cord malformation and tethered cord syndrome are challenging pathologies in the pediatric population. During 2016–2022, 56 cases of split cord malformation (SCM) and tethered cord syndrome were treated at the Republican Specialized Scientific Medical Practical Center of Neurosurgery (RSSMPCN) of Uzbekistan. This article aims to provide a retrospective analysis of the clinical presentation, radiological findings, and surgical outcomes of patients with split cord malformation and tethered cord syndrome. MethodsThe retrospective study was conducted for 56 pediatric patients with split cord malformation and tethered cord syndrome during the abovementioned six-year period. All patients underwent MR imaging with computed tomography, followed by surgery with intraoperative neurophysiological monitoring. Each patient underwent follow-up examinations at 3 and 6 months postoperatively and yearly thereafter. ResultsThe mean patient age was 5.7 years (10 months to 15 years), and the male-to-female ratio was 1:2.2. Encouragingly, 44 (78.6 %) of the 56 patients showed improved neurological status postoperatively. Even in the cases where spur resection procedures were performed, there was partial neurological improvement, demonstrating the overall positive outcomes of the surgeries. Importantly, none of the 56 patients had neurological deteriorations in the postoperative period ConclusionsSplit cord malformation is a rare but challenging pathology of childhood. The presentation is primarily characterized by movement, sensory or bowel disorders, and back and leg pain. This underscores the importance of early recognition and intervention when neurological symptoms are evident. Surgical intervention, as demonstrated in our study, is both appropriate and efficient in improving the neurological status of the patients.

Split Cord Malformation Presentation and Management in Pediatric and Adult Cases: a Case Series.

The primary purpose of this study was to enhance the understanding of diastematomyelia, with a particular focus on adult-onset cases, which are infrequent and not fully elucidated. Additionally, the study sought to analyse the clinical features, diagnostic characteristics, and surgical interventions employed to manage the condition. This retrospective case series aimed to investigate diastematomyelia, a rare congenital deformation affecting the spinal cord. The study included 16 patients diagnosed with diastematomyelia, consisting of 13 pediatric cases (mean age: 7.6years, age range: 5months to 13years) and 3 adult cases (mean age: 36years, age range: 26 to 48years). Among the paediatric cases, 9 were females, and 4 were males, while the adult cohort comprised 2 males and 1 female. The study design involved a thorough review of medical records, imaging reports, and surgical outcomes without specific inclusion or exclusion criteria. Surgical intervention emerged as the primary treatment modality for all cases, except one. Following surgical intervention, significant improvements were observed in pain management, motor function, and bladder control. Furthermore, additional findings indicated the presence of Dural Ectasia and Vertebral segmentation defects among the study population. This retrospective case series sheds light on the clinical features and surgical outcomes of diastematomyelia in both pediatric and adult patients. The findings underscore the importance of surgical intervention in alleviating symptoms and enhancing motor coordination and bladder control.

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

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

Quality of Life of Children Treated for Split Cord Malformation

PurposeSplit cord malformation (SCM), associated with neurological deficits, necessitates surgical intervention for spinal cord de-tethering. Limited evidence exists regarding its impact on children's quality of life. Our study aims to evaluate the postoperative quality of life in children treated for split cord malformation. MethodsThis retrospective cohort study examined records of patients with split cord malformation operated on between July 1, 2012, and July 31, 2022, at a single center. Data, including Health Utility Index-3 (HUI-3) scores provided by guardians, was collected to assess quality of life. Clinical and neurological outcomes were also analyzed. ResultsTwenty-five patients, predominantly females (68%), with a median age of 7 years, were included. Most presented with normal motor function (76%). The most common anatomic level of split cord malformation was lumbar (12 48%) followed by lumbosacral (5, 20%). A bony spur from the lamina was the most common cause of splitting the cord (64%). Over a median follow-up of 3.3 years, 64% showed neurological stability, 16% showed neurological improvement, and 4% experienced deterioration. The mean HUI-3 score for 21 children was 0.93 ± 0.24. ConclusionSurgical management of split cord malformation demonstrated favorable neurological outcomes and a positive long-term quality of life, as evidenced by HUI-3 scores. Our findings emphasize the efficacy of surgical intervention in improving the lives of children with this condition.

Preliminary Experience with 3-Dimensional-Exoscopic Untethering of a Type II Diastematomyelia: Technical Note and Review of the Literature

ObjectiveThe aim of this paper is to describe the use of high-definition 3D exoscope (VITOM 3D exoscope - Karl Storz GmbH, Tuttlingen, Germany) for the neurosurgical treatment of a rare pediatric disease, type II diastematomyelia with associated tethered cord. MethodsA 13-year-old girl suffering diastematomyelia type II with a tethered cord was surgically treated with the aid of a high-definition 3D exoscope, with a third operator moving and pivoting its arm. Intraoperative monitoring and mapping was arranged. The surgery required a bilateral access to address both the split cord malformation and the tethering of the filum terminale. The filum terminale was identified and cut, and the connective fibrovascular tissue separating the two medullary halves were unraveled. These steps were performed with no changes of intraoperative monitoring. Pertinent literature has been carefully addressed ResultsThe surgery was successful, and the patient was discharged home on the eleventh postoperative day without any complications. The 3-month postoperative MRI demonstrated regular surgical outcomes; no dynamic motor disturbances were reported. To our knowledge this is the first spinal congenital malformation treated with the use of a 3D exoscope. ConclusionsThe use of 3D exoscope is advancing in spinal surgery, as it provides magnification, stereopsis, lighting and definition comparable to the operating microscope; the addition of a third operator simplified the operations of moving around the arm, releasing these burdens for the surgeons. Our preliminary experience proved that the use of a 3D exoscope is feasible and safe for surgical management of a type II diastematomyelia with tethered cord.

Results of Surgical Treatment of Occult Spinal Dysraphisms-A Single Centre Experience.

Occult spinal dysraphisms (OSDs) are caused by various defects in the embryogenesis of the spinal cord and represent an obstacle to the ascent of the conus, which allows the conus to pass from the lower levels of the spinal canal to the final position between L1 and L2 during normal foetal life. When an OSD tethers the spinal cord at the lower levels, it can lead to neurological symptoms, better known as tethered cord syndrome. Surgical treatment of OSD is primarily aimed at untethering the spinal cord. In asymptomatic patients, this can protect against the long-term development of neurological deficits. In symptomatic patients, this can halt or limit the progression of existing symptoms. The aim of this study is to examine all paediatric and adult patients diagnosed with OSD and treated in the Department of Neurosurgery at the University Medical Centre Ljubljana during the 5-year period of 2016-2021. All patients diagnosed with OSD during this period were included in the study. Patient characteristics, treatment modalities and outcomes were studied with the aim of describing the differences between the paediatric and adult population and defining the rationality of treating these pathological conditions. We included in the study 52 patients with 64 occult dysraphic lesions. Adults (>18 years old) represented 15/52 (28.8%) of all patients, while 37/52 (71.8%) were children. The most common OSDs were conus lipomas, followed by dermal sinus tracts, filum terminale lipomas and split cord malformations. Surgical treatment was performed in 35/52 (67.3%) cases, while conservative management was chosen in 17/52 (32.6%) cases. The preoperative presence of symptoms was statistically higher in adults than in children (p = 0.0098). Surgery on complex spinal cord lipomas was statistically related to a higher rate of postoperative neurological complications (p = 0.0002). The treatment of OSD is complex and must be based on knowledge of the developmental anomalies of the spine and spinal cord. Successful surgical treatment relies on microsurgical techniques and the use of neuromonitoring. Successful treatment can prevent or limit the occurrence of neurological problems.

Association of spinal cord abnormalities with vertebral anomalies: an embryological perspective.

To analyze the relationship between spinal cord and vertebral abnormalities from the point of view of embryology. We analyzed the clinical and radiological data of 260 children with different types of spinal cord malformations in combination with vertebral abnormalities. Among 260 individuals, approximately 109 presented with open neural tube defects (ONTDs), 83 with split cord malformations (SCMs), and 83 with different types of spinal lipomas. Pathological spina bifida emerged as the most frequent vertebral anomaly, affecting 232 patients, with a higher prevalence in ONTD. Vertebral segmentation disorders, including unsegmented bars, butterfly vertebrae, and hemivertebrae, were present in 124 cases, with a higher prevalence in SCM. The third most common spinal anomaly group consisted of various forms of sacral agenesis (58 cases), notably associated with blunt conus medullaris, spinal lipomas, and sacral myelomeningocele. Segmental aplasia of the spinal cord had a typical association with segmental spinal absence (N = 17). The association between SCM and neuroenteric cyst/canal and vertebral segmentation disorders is strong. High ONTDs often coincide with pathological spina bifida posterior. Type 1 spinal lipomas and focal spinal nondisjunction also correlate with pathologic spina bifida. Segmental spinal absence or dysgenesis involves localized spinal and spinal cord aplasia, sometimes with secondary filar lipoma.

Skull-femoral traction followed by osteotomy correction is a safe and effective treatment for severe scoliosis with split cord malformation.

This study aimed to evaluate the safety and efficacy of skull-femoral traction followed by osteotomy correction in patients with severe spinal scoliosis and split cord malformation. We retrospectively analyzed ten cases of severe spinal scoliosis with Pang I type split cord malformation treated between August 2012 and August 2023. Patients underwent skull-femoral traction prior to osteotomy correction. We assessed changes in height, weight, coronal and sagittal Cobb's angles, and physiological indicators such as vital capacity (VC), forced vital capacity (FVC), forced expiratory volume in one second (FEV1), and blood gas levels before, during, and after treatment. Traction duration ranged from 9 to 19 days, with height and weight showing significant increases post-treatment. The coronal Cobb's angle improved from pre-treatment to post-corrective surgery and remained stable at the final follow-up. Similar improvements were observed in the sagittal plane. Physiological indicators such as VC, FVC, and FEV1, as well as blood gas levels, normalized after treatment. Nutritional status, indicated by triceps skinfold thickness, albumin, and transferrin concentrations, also improved. No neurological complications or device-related complications occurred during or after treatment. Skull-femoral traction followed by osteotomy correction is a safe and effective treatment for severe spinal scoliosis with split cord malformation, offering an alternative to high-risk procedures.

Dorsal bony spur in pediatric split cord malformations: eight-year experience from a tertiary care hospital.

Dorsal spurs in Type I split cord malformations (SCM-I) are infrequent findings. The pathogenesis of the same is debatable. The objective of this study is to analyze our experience with SCM-I patients having dorsal bony spurs. Retrospective analysis of SCM patients operated from 2010 to 2017 was performed. Their demographic profile, clinic-radiological features, operative findings, and outcome following surgery were recorded. Twenty-four cases of Type I SCM harboring dorsal bony spurs were identified with mean age of 4.96years. The commonest split site was lumbar, documented in 62.5%. Scoliosis was observed in 58.3%. Pre-operative neurological deficits were seen in 66.6% cases with asymmetric weakness of limbs seen in 16.6%. There was no new neurological deficit observed post-operatively. This is the largest series of dorsal spurs occurring in SCM, reported in literature so far. Meticulous pre-operative evaluation and imaging are important to identify dorsal spurs for appropriate management and good clinical outcome. Differentiating dorsal spur from ventral spur is important as it has a bearing on surgical approach.

Evaluation of split cord malformation between years 2006 and 2020: A case series study

BackgroundSplit spinal cord malformation (SCM) is a rare congenital disorder leading to the split of the spinal cord by a bony or fibrous septum. ObjectivesIn the current study, we aimed to evaluate the patients with SCM who underwent surgery between 2006 and 2020. MethodsIn this case series, thirty-five patients with SCM who underwent septal resection or spinal cord release surgery were enrolled and evaluated for type and site of the septum, accompanying some anomalies, such as neurological abnormalities, spinal deformities, and skin lesions. Also, the changes of neurological symptoms after surgery were securitized. ResultsThirty-five patients, including 27 females and 8 males, have been investigated. Scoliosis and Tethered cord syndrome were the most prevalent anomalies in 24 and 26 patients, respectively. The most common skin lesion was focal hirsutism in 14 patients, and the most common neurological disorder was the reduced muscle force observed in 5 patients, which was improved in two cases following surgeries. ConclusionSCM occurred more frequently in females in comparison with males (77.14% in females and 22.85% in males). Scoliosis and Tethered cord syndrome were two dominant accompanying disorders with SCM. Moreover, focal hirsutism and reduced muscle force were the most common skin lesion and neurological disorders, respectively in these patients, respectively.

Changes in Spina Bifida Lesion Level After Folic Acid Fortification in the US

Changes in Spina Bifida Lesion Level After Folic Acid Fortification in the US

Multiple Split Cord Malformation with Dysplasia of the Hip Joints: A Rare Association or Part of a Sydromic Presentation

Abstract Background: Multiple level split cord malformations (SCMs) with associated skeletal abnormality are rare. Here we discuss a 3-year-old male child with double-level SCM type 1 and developmental dysplasia of the hip joints. Case: A 3-year-old male child presented with chronic constipation since birth with urinary incontinence. There was gait abnormality and he could not able stand without support. Radiology showed SCM type 1 at the level of D9-11 and L4. X-ray showed left dysplastic hip joints. Surgically both the bony spurs were resected and dural sac was repaired along with detethering of the low-lying filum. Orthopedic intervention was done after 3 months. At 18-month follow-up the child has improved bowel and bladder symptoms and could able to walk independently. Conclusion: Though rare, skeletal abnormalities like dysplastic hip joints may be associated with SCM. Early diagnosis and management of both conditions have better outcomes.

Gastrulation and Split Cord Malformation.

Split cord malformation (SCM) is a rare form of closed spinal dysraphism, in which two hemi-cords are present, instead of a single spinal cord. SCM is categorised into type 1 and type 2. Type 1 SCM is defined by the presence of a bony or osseocartilaginous spur between the hemi-cords, whereas type 2 SCM has no bony spur, and the two hemi-cords are contained within a single dura. In this chapter, we present the putative mechanisms by which SCM arises, including gastrulation defects and Pang's unified theory. The typical and rare clinical presentations and variations are described. Finally, we outline the step-by-step surgical approach to both SCM 1 and 2 and the overall prognosis of both conditions.

An Unusual Case of Neurenteric Cyst in a Patient with Split Cord Malformation

Neurenteric cyst in a split cord malformation is a rare finding. We report an adult female becoming acutely symptomatic secondary to an expanding neurenteric cyst, though previous imaging had demonstrated stability. We discuss our workup and management with surgical resection and possible etiologies of her acute decline.

Cisternostomy In Lipomyelomeningocele Without Hydrocephalus: A Case Report

Introduction: Spinal dysraphisms can be classified as either open or closed dysraphisms. Closed spinal dysraphisms such as lipomyelomeningocele, diastematomyelia, and spina bifida occulta have no exposed neural tissue and are accompanied by cutaneous markers in 43%–95% of cases, and include lesions such as subcutaneous masses, capillary hemangioma, dimples, and hairy nevus. These cutaneous markers can be used to recognize cases in an asymptomatic neonate. LMMC can be associated with additional pathologies, including Chiari malformation type 1 (13%), spina bifida (14.4%), split cord malformations (3.1%), associated dermal sinuses (3.1%), dermoid or epidermoid cysts (3.1%), diastematomyelia (3.1%), terminal hydromyelia (3.1%), anal stenosis (1.0%), and Down syndrome (1.0%). Case Report: A year old girl, came to our department with chief complaint of lump on the back since the patient was born. No history of increased intracranial pressure was complained. On physical examination, there is no maceration on the lump, and there is no sign of ruptured lump on the back. Patient also has active motoric on all extremity. We diagnosed the patient with spina bifida. We did CT scan of the head to rule out hydrocephalus and MRI for the confirmation of spina bifida. Excision of cele was done. Postoperatively, there is an increased of csf leak of the patient from the excised cele and we decided to do cisternostomy. After cisternotomy, there is no increased of leakage and patient also have good motoric function. Patient was treated in our outpatient clinic and has good recovery after surgery. Discussion: Lipomyelomeningocele is a rare but complicated defect, lying in the spectrum of occult neural tube defects. It is actually a form of occult spinal dysraphism in which a subcutaneous fibrofatty mass traverses the lumbodorsal fascia, causes a spinal laminar defect, displaces the dura, and infiltrates and tethers the spinal cord. Spinal lipomas and LMMCs are frequently associated with cutaneous and musculoskeletal abnormalities in addition to sensorimotor deficits and urological dysfunction. Cutaneous lesions include subcutaneous lipomas, capillary hemangiomas, complex dimples, and hypertrichosis, whereas complex malformations, such as dermal appendages, are rare. Magnetic resonance imaging is useful in demonstrating the presence of a fatty mass and cord tethering. Surgical objectives in a lipomyelomeningocele repair include removal of the adipose mass, identification of the defect in the lumbosacral fascia for release of the tether, possible release of the filum terminale, preservation of neural elements, and prevention of retethering of the spinal cord. After operation for lipomyelomeningocele, the cord may not be completely untethered, or after a short period may retether Discussion: Cisternostomy may be done in cases of spina bifida without hydrocephalus in our experience

PEDIATRIC SPINAL DYSRAPHISM ON MAGNETIC RESONANCE IMAGING: TRENDS IN A TERTIARY CARE HOSPITAL IN NORTH INDIA

Background: Spine and spinal cord development is governed by intricate genetic mechanisms and any deviation from the normal embryological cascade during 2-6 gestational weeks causes imperfect fusion of midline mesenchymal, bony and neural structures causing spinal dysraphism. Imaging plays a pivotal role in their evaluation as many patients present with concurrent anomalies that need to be corrected simultaneously to avoid repeat surgeries. To demonstrate the spectrum of MRI ndings of spinal dysraphi Aim: Settings and design: sm. A cross sectional observational study was done in 36 pediatric patients with known or suspected spinal dysraphism on 3T MRI. MRI was Materials And Methods: performed using Siemens Skyra 3T MRI. In this study comprising of 36 patients, mean age Results: was 37.1months (3 years 1month) with minimum age of 4 days and maximum age of 18 years. Children of age less than 5 years were maximally affected. A female predominance was noted with male: female ratio of 0.9:1. Open spinal dysraphism (55.6%) was more common than closed dysraphism (44.4%). The most common dysraphism was myelomeningocele. Among open dysraphism, we also encountered 1 case each of hemimyelomeningocele and myelocele. Among closed defects, split cord malformation was most common (19.4%) as it was present with other dysraphic defects (called complex spina bida), followed by lipomyelocele (11.1%) and dermal sinus (11.1%). Among 7 cases of split cord malformation, type II (6 cases; 85.7%) was more common than type I (1 case; 14.3%). Other cases of closed dysraphism were lipomyelomeningocele, meningocele, terminal myelocystocele, intradural lipoma, lar lipoma and caudal regression syndrome. MRI is an excelle Conclusion: nt modality for dening the characteristic imaging features of each dysraphism to give a composite diagnosis.

Prenatally diagnosed fetal thoraco-lumbar spine duplication associated with lipomyelomeningocele: An extremely rare case of split cord malformation.

Spine duplication is considered rare, a more serious form of split cord malformation. Ultrasonographic evaluation of the spine in the second trimester is central to the antenatal diagnosis of spinal malformations. Here, we report a case of thoraco-lumbar spine duplication associated with lipomyelomeningocele diagnosed by ultrasonography at 19 weeks of gestation. To the best of our knowledge, this is the first case report of spine duplication diagnosed by antenatal ultrasonography.

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.

BACKGROUNDMultiple-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.OBSERVATIONSA 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.LESSONSThe 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.