Surgical experience of 120 patients with lumbosacral lipomas

A case of spinal arteriovenous fistula complicated with congenital spinal lipoma and successfully treated with endovascular therapy

Spinal cord lipomas concurrent with spinal arteriovenous fistulas (SAVFs) are rare, and their natural history and optimal treatment remain unclear. We report the case of a 44-year-old woman with a history of surgical intervention at 2 months of age for myelomeningocele, with the possibility of lipmyelomingocele based on the surgical history, who presented with progressive paralysis and paresthesia in both lower extremities over 3 years. She was diagnosed with an SAVF concurrent with a congenital spinal lipoma, and transarterial embolization was performed after confirming the absence of neurological symptoms during a provocation test. Postoperative imaging showed reduced T2-weighted high-intensity signals in the spinal cord, and 3 months after the procedure, her neurological symptoms improved significantly, allowing her to transition from nonambulatory wheelchair dependence to ambulation with a double cane. This case highlights the need for detailed imaging and vascular evaluation in patients with spinal lipomas and SAVFs, especially in cases involving the filum terminale type, which is closely associated with the anterior spinal artery. Proximal occlusion may occur if feeders have multiple branches or a long distance to the drainer, increasing the risk of incomplete treatment. A provocation test before embolization can enhance both safety and efficacy.

A retrospective analysis of spinal teratomas and spinal lipomas: overlaps and differences in presentation, surgical treatments, and outcomes

BACKGROUND

Spinal teratomas and lipomas, both adult and pediatric cases, are rare diseases with many similarities, but have yet to be systematically compared.

PURPOSE

To systematically compare spinal teratomas and lipomas to optimize management.

STUDY DESIGN

Retrospective.

PATIENT SAMPLE

Symptomatic spinal teratoma and lipoma patients surgically treated at our center.

OUTCOME MEASURES

Anatomical distribution, clinical manifestations, resection status, and outcomes.

METHODS

Spinal teratoma and lipoma patients with complete data treated during 2008 to 2023 in our center were enrolled. Electrophysiological monitoring was routinely performed after 2012. Patient characteristics, anatomical distribution, clinical manifestations, surgical resection, and outcomes were analyzed.

RESULTS

We enrolled 86 teratoma patients (71 adults) and 51 lipoma patients (39 adults). Most tumors were lumbosacral lesions; cervical/thoracic involvement was more common with lipomas. Pain, the most frequent manifestation, was more common in teratomas. Gross total resection (GTR) was achieved in 51.1% and 49% of teratomas and lipomas, respectively. Electrophysiological monitoring increased the GTR rate from 38.8% to 48.6%. Age independently predicted (OR: 1.040, 95% CI: 1.008-1.078) GTR/near-total resection (NTR). Symptom relief occurred in 81.4% teratoma patients and 64.7% lipoma patients. Recurrence/symptomatic progression occurred in 19 teratomas and 7 lipomas after a median of 95 and 115 months, respectively. Adult lipoma patients without spinal dysraphism had lower recurrence rates. GTR (HR: 0.172, 95% CI: 0.02557-0.7028) and lesion length (HR: 1.351, 95% CI: 1.138-1.607) independently predicted recurrence/progression.

CONCLUSIONS

GTR should be pursued for adult/pediatric spinal teratomas and pediatric spinal lipomas. For adult spinal lipoma patients without dysraphism, conservative surgery could be considered.

Neurosurgical strategy based on the type of occult spinal dysraphism in omphalocele-exstrophy-imperforate anus-spinal defects complex: A review of 10 cases

Background

Omphalocele-exstrophy-imperforate anus-spinal defects (OEIS) complex is a rare, life-threatening congenital malformation primarily treated with abdominogenital repair. The optimal indication and timing of neurosurgical interventions for the associated spinal cord lesions remains insufficiently studied. We reviewed spinal dysraphism in OEIS to evaluate the best timing for neurosurgical intervention.

Methods

We retrospectively reviewed 10 patients with OEIS, analyzing their clinical and imaging data, as well as surgical and pathological findings.

Results

Terminal myelocystocele (TMCC) and spinal lipomas were observed in 5 patients each. Of the spinal lipomas, one had a single filar lipoma, while four had double lipomas (3 caudal and dorsal; 1 filar and dorsal). TMCC manifested with severe lower limb motor dysfunction in addition to abdominogenital disorder at birth, with the cyst-induced lumbosacral mass increasing over time. Spinal lipomas were less symptomatic except for abdominogenital issues and demonstrated minimal growth of the intraspinal lipoma over time. Untethering surgery was performed in 8 patients (5 TMCC; 3 spinal lipomas) at a median age of 3 (range, 2-10) months for TMCC and 6 (range, 2-14) months for spinal lipomas. One TMCC patient (surgery at 10 months) experienced postoperative cerebrospinal fluid leakage, necessitating three reoperations.

Conclusion

Magnetic resonance imaging is essential to diagnose spinal cord malformations accurately. The necessity and timing of surgical intervention differ between TMCC and spinal lipomas. Since TMCC lesions tend to enlarge, surgery should be performed as soon as the patient's abdominogenital condition stabilizes. For spinal lipomas, surgery should be considered carefully based on the patient's neurological condition.

Glial fibrillary acidic protein immunopositive neuroglial tissues with or without ependyma-lined canal in spinal lipoma of filar type: Relationship with retained medullary cord

Background

Retained medullary cord (RMC) and filar lipomas are believed to originate from secondary neurulation failure; filar lipomas are reported to histopathologically contain a central canal-like ependyma-lined lumen with surrounding neuroglial tissue with ependyma-lined central canal (NGT w/E-LC) as a remnant of the medullary cord, which is a characteristic histopathology of RMC. With the addition of glial fibrillary acidic protein (GFAP) immunostaining, we reported the presence of GFAP-positive NGT without E-LCs (NGT w/o E-LCs) in RMC and filar lipomas, and we believe that both have the same embryopathological significance.

Methods

We examined the frequency of GFAP-positive NGT, with or without E-LC, in 91 patients with filar lipoma.

Results

Eight patients (8.8%) had NGT w/E-LC, 25 patients (27.5%) had NGT w/o E-LC, and 18 patients (19.8%) had tiny NGT w/o E-LC that could only be identified by GFAP immunostaining. Combining these subgroups, 56% of the patients (n = 51) with filar lipoma had GFAP immunopositive NGT.

Conclusion

The fact that more than half of filar lipomas have NGT provides further evidence that filar lipoma and RMC can be considered consequences of a continuum of regression failure that occurs during late secondary neurulation.

Preoperative interactive virtual simulation applying three-dimensional multifusion images using a haptic device for lumbosacral lipoma

PURPOSE

Untethering surgery for lumbosacral lipoma is a preventive procedure, and avoidance of complications and good long-term outcomes are required. We introduced presurgical interactive virtual simulation (IVS) applying three-dimensional multifusion images using a haptic device aimed at improving operative outcomes.

METHODS

Fourteen patients with newly diagnosed lumbosacral lipoma were recruited and underwent preoperative IVS. The median age at surgery was 8 months. A three-dimensional image analysis system was used to extract and fuse structures necessary for surgery, such as the lipoma, spinal cord and skin, from CT and MRI, and create three-dimensional multifusion images. The created images were individually converted to standard triangulated language format and loaded onto a workstation (Geomagic freeform™) that could be freely transformed, and the laminectomy range and lipoma extraction procedure were examined. Presurgical IVS was performed, and the actual surgery was performed.

RESULTS

The disease types were dorsal, caudal, lipomyelomeningocele, transitional, and filum in 5, 5, 2, 1, and 1 patients, respectively. The surgical procedure and extent of the laminectomy were as planned for all patients. Resection of the lipomas tended to be less than expected preoperatively because of positive reactions on intraoperative monitoring. No postoperative complications were observed. The median postoperative follow-up period was 29 months, and there were no reoperations during the observation period.

CONCLUSIONS

Although there are various types of lumbosacral lipoma, surgery can be safely performed by performing presurgical IVS. The short-term course is good; however, long-term follow-up is necessary for the appearance of neurological symptoms associated with growth and re-tethering.

Spinal cord lipomas: lessons learned in the era of total resection

PURPOSE

Recent years have seen a paradigm shift towards total/near-total resection in spinal cord lipoma surgery. As this procedure is technically challenging, surgical candidates need to be selected appropriately through accurate image assessment and classification. The purpose of this paper is to describe a surgical series of paediatric spinal cord lipomas, their diagnosis, results and complications.

METHODS

We undertook a retrospective review of paediatric patients with spinal cord lipomas who underwent surgery between 2008 and 2022. The variables studied were age, gender, preoperative symptoms according to the Necker Functional Score (NFS), type of lipoma according to Morota's classification, functional and radiological surgical outcomes using the cord-sac ratio (CSR), need for re-operation, complications and follow-up.

RESULTS

A total of 25 patients (average age 36 months) underwent surgery. According to Morota's classification, MRI showed 13 type 1 lipomas, two type 2, two type 3 and eight type 4. The preoperative NFS was 16.06, with urological abnormalities being the most frequent manifestation. Total/near-total resection was attempted since 2015. Five patients with type 1 lipoma required re-operation due to clinical deterioration with suspected retethering, all of them with a CSR > 0.3. The series average CSR was 0.417.

CONCLUSIONS

This paper highlights the importance of proper classification for a correct surgical approach to obtain favourable results and minimise possible complications. Based on our experience, given our results regarding the percentage of fistulae and retethering rates, we limited radical resection to symptomatic type 1 lipomas. Our future aim is to obtain better CSR rates and to decrease the retethering percentage.

Lumbosacral lipoma in childhood, how strong is the evidence base? A systematic review

OBJECTIVE

Conus region lumbosacral lipomas (LSLs) are highly heterogeneous in their morphology, clinical presentation, and outcome, with an incompletely understood natural history and often treacherous surgical anatomy. This systematic review aims to critically evaluate and assess the strength of the current LSL evidence base to guide management strategies.

METHODS

According to a systematic review following PRISMA guidelines, a search was conducted using the key term "lumbosacral lipoma" across MEDLINE (OVID), Embase, Cochrane Library, and PubMed databases from January 1951 to April 2021. All studies containing ten or more paediatric conus lipomas were included. Data heterogeneity and bias were assessed.

RESULTS

A total of 13 studies were included, containing 913 LSLs (predominantly transitional type-58.5%). Two-thirds (67.5%) of all patients (treated and non-treated) remained clinically stable and 17.6% deteriorated. Neuropathic bladder was present in 8.6% at final follow-up. Of patients managed surgically, near-total resection vs. subtotal resection deterioration-free survival rates were 77.2-98.4% and 10-67% respectively. 4.5% (0.0-27.3%) required re-do untethering surgery. Outcomes varied according to lipoma type. Most publications contained heterogeneous populations and used variable terminology. There was a lack of consistency in reported outcomes.

CONCLUSION

Amongst published series, there is wide variability in patient factors such as lipoma type, patient age, and methods of (particularly urological) assessment. Currently, there is insufficient evidence base upon which to make clear recommendations for the management of children with LSL. There is an imperative for neurosurgeons, neuroradiologists, and urologists to collaborate to better standardise the terminology, assessment tools, and surgical interventions for this challenging group of conditions.

Complex lumbosacral spinal cord lipomas: A longitudinal study on outcomes from a Singapore children's hospital

BACKGROUND

Total/near-total resection (TR/NTR) of complex lumbosacral lipomas (CSL) is reported to be associated with better long-term functional outcomes and lower symptomatic re-tethering rates. We report our institutional experience for CSL resection in affected children.

METHODS

This is a single-institution, retrospective study. Inclusion criteria consist of patients with CSL with dorsal, transitional and chaotic lipomas based on Pang et al's classification. The study population is divided into 2 groups: asymptomatic patients with a normal preoperative workup referred to as 'prophylactic intent' and 'therapeutic intent' for those with pre-existing neuro-urological symptoms. Primary aims are to review factors that affect post-operative clean intermittent catheterization (CIC), functional outcomes based on Necker functional score (NFS), and re-tethering rates.

RESULTS

122 patients were included from 2000 to 2021. There were 32 dorsal lipomas (26.2 %), 74 transitional lipomas (60.7 %), and 16 chaotic lipomas (13.1 %). 82 % patients achieved TR/NTR. Favourable NFS at 1-year was 48.2 %. The re-tethering rate was 6.6 %. After multivariable analysis, post-operative CIC was associated with median age at surgery (p = 0.026), lipoma type (p = 0.029), conus height (p = 0.048) and prophylactic intent (p < 0.001). Next, extent of lipoma resection (p = 0.012) and the post-operative CSF leak (p = 0.004) were associated with re-tethering. Favourable NFS was associated with lipoma type (p = 0.047) and prophylactic intent surgery (p < 0.001).

CONCLUSIONS

Our experience shows that TR/NTR for CSL is a feasible option to prevent functional deterioration and re-tethering. Efforts are needed to work on factors associated with post-operative CIC.

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.

Chaotic lipoma with proximal syrinx -a (not so) rare variant - review of the literature, possible embryology and management

Chaotic lipomas are an extremely rare variant of spinal lipomas. This entity was first defined in 2009 by Pang and colleagues. Not much has been written about this variant. Its characteristic is the haphazard distribution of DREZ (Dorsal root entry zone), nerve roots and placode-lipoma interface. Thus complete/near-total excision of this lesion is quite difficult. We describe a case of chaotic spinal lipoma and elucidate the challenges faced in the management of this entity and review the literature. We performed a thorough systematic review with the keyword 'chaotic', 'Lipomyelomeningocele', 'Complex Lipomyelomeningocele', 'LMMC', 'Lumbar lipoma', 'spinal lipoma' in the google scholar and PUBMED data system for indexed literature on the above topic with no particular time frame. The studies quoted range earliest from 1970 till currently. Additional potential relevant articles were further retrieved through a manual search of references from original reports. Out of 42 studies, a total of 21 publications were selected which could have encountered a chaotic variant, but due to the term introduced only recently in 2009, may have been described differently. Studies encompassing true lipomeningomyelocele were excluded from our review. What we found out? Chaotic lipoma may not be a new entity. The scarce description in literature may be in part due to non-introduction and unclear description of this term earlier. The management of this variant is particularly challenging with basic principles remaining the same. Meticulous near-total excision and placode-lipoma construct are the major obstacles.

Role of Magnetic Resonance Imaging in the Screening of Closed Spinal Dysraphism

Closed spinal dysraphism (CSD) encompasses a heterogeneous group of spinal cord deformities, which can be accompanied by several types of skin stigmata. These skin stigmata may include inconspicuous features, such as sacral dimples and deformed gluteal clefts, but the association between such mild skin stigmata and CSD is uncertain. This study aimed to reevaluate the indication for magnetic resonance imaging (MRI) in patients with skin stigmata while considering the indication for surgery. A retrospective analysis was conducted on magnetic resonance images of 1255 asymptomatic children with skin stigmata between 2003 and 2015. Skin stigmata classification was based on medical chart data. All subtypes of CSDs except for filum terminale lipomas (FTL), FTL thicker than 2 mm or with low conus medullaris, were considered to meet the surgical indication. CSD prevalence was estimated while considering the surgical indications and assessed after excluding all FTL cases. Skin stigmata were classified into seven types, dimple, deformed gluteal cleft, hair, subcutaneous mass, appendage, discoloration, and protruding bone, and included 1056 isolated and 199 complex ones. The prevalence of CSD was 19.5%, 6.8%, and 0.5% among patients with isolated dimples (n = 881) and 13.9%, 5.8%, and 0.7% among those with isolated deformed gluteal clefts (n = 136) for all cases, surgical indications, and patients without FTL, respectively. Dimples and deformed gluteal clefts had a low prevalence of CSD requiring surgical intervention, and cases without FTL were rare. Asymptomatic patients with mild skin stigmata may not require immediate MRI.

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.

Comparison of intraoperative neurophysiological monitoring methods for lumbosacral lipoma surgery in infants

BACKGROUND

Stable intraoperative neurophysiology monitoring of infants, especially very young infants, is challenging. In this study, motor evoked potentials (MEPs), the bulbocavernosus reflex (BCR), and somatosensory evoked potentials (SEPs) were simultaneously monitored in infants with lumbosacral lipomas, and these methods were compared retrospectively.

METHODS

A total of 21 surgeries performed for lumbosacral lipoma in patients less than 1 year old were studied. The mean age at surgery was 133.8 days (range 21-287 days; ≤ 120 days: 9 cases, > 120 days: 12 cases). Transcranial MEPs were measured in the anal sphincter and gastrocnemius, and tibialis anterior and other muscles were added as needed. The BCR was measured by the electromyogram of the anal sphincter muscle with stimulation of the pubic region, and SEPs were measured from the waveforms of stimulation of the posterior tibial nerves.

RESULTS

For the BCR, stable potentials could be recorded for all 9 cases at ≤ 120 days of age. In contrast, for MEPs, stable potentials could be recorded in only 4 of 9 cases (p < 0.05). For all patients > 120 days of age, MEPs and the BCR were measurable. SEPs were undetectable in some patients regardless of age.

CONCLUSION

The BCR could be more consistently measured than MEPs in infant patients with lumbosacral lipoma at ≤ 120 days of age.

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.

Urodynamics findings pre- and post-untethering surgery in children with filum lipoma: A single-institution experience

OBJECTIVES

We aimed to investigate the changes in urodynamics and voiding cystourethrogram parameters on pre- and post-untethering surgery in patients aged under 2 years with filum lipoma.

METHODS

Sixty-two patients were enrolled in this study. The changes in urodynamics and voiding cystourethrogram parameters were compared before untethering surgery and 6 months after untethering surgery. These parameters were bladder volume, bladder deformity, vesicoureteral reflux during voiding cystourethrogram, detrusor overactivity, bladder compliance, and post-void residual volume in urodynamics.

RESULTS

Bladder volume during voiding cystourethrogram and bladder compliance increased significantly from 89.8 ± 49.5 mL to 114.5 ± 50.5 mL (P = 0.0069) and 10.2 ± 6.2 mL/mmH2 O to 17.0 ± 13.3 mL/mmH2 O (P = 0.0008), respectively, at 6-month follow-up. Six patients required combination management with clean intermittent catheterization at 25.1 ± 8.2 months (14.3 ± 6.5-months follow-up) because of elevated post-void residual volumes.

CONCLUSIONS

According to voiding cystourethrogram results, bladder function and urodynamics in patients with filum lipoma significantly improved after untethering surgery. Non-invasive assessment based on measurements of post-void residual should be considered as a postoperative follow-up method.

Risk factors for pre-operative functional deterioration in children with lipomyelomeningocele

PURPOSE

To characterize the temporal profile of pre-operative deterioration in children with lipomyelomeningocele (LMMC) including those with congenital deficits and identify risk factors for clinical worsening.

METHODS

Records of 87 children who underwent surgery for LMMC were retrospectively reviewed to study the temporal profile of pre-operative deterioration, defined by the onset of new neurological dysfunction or progression of a pre-existing deficit. Preoperative magnetic resonance imaging (MRI) studies were examined to identify radiological features associated with deterioration. In children with extra-spinal placodes, the angle subtended by the terminal placode with the cord at the level of the laminar-fascial defect ("J sign") was assessed.

RESULTS

Pre-operative deterioration in function was seen in 37 children (43%), occurring at a median age of 36 months and was more frequent in children without congenital deficits (54% versus 27%; p = 0.016). On Cox regression analysis, extra-spinal location of the placode (p = 0.003) and presence of a congenital deficit (p = 0.009) were positively and negatively associated with deterioration respectively. On Kaplan-Meier analysis, the median deterioration-free survival time was 72 months and was positively associated with presence of congenital deficit (p = 0.026) and negatively associated with presence of an extra-spinal placode (p < 0.001) or a meningocele sac (p = 0.001).

CONCLUSION

Extra-spinal location of the neural placode was associated with higher risk of clinical deterioration in children with LMMC, whereas the presence of a congenital deficit conferred a decreased risk. Risk stratification based on clinical and radiological features can be used to guide decisions regarding early prophylactic surgery in children with LMMC.

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.

Retethering risk in pediatric spinal lipoma of the conus medullaris

OBJECTIVE

Lipoma of the conus medullaris (LCM) causes neurological symptoms known as tethered cord syndrome (TCS). The symptoms can be seen at diagnosis and during long-term follow-up. In this report, pediatric patients with LCMs who underwent untethering surgery, under the policy of performing surgery if diagnosed regardless of symptoms, were retrospectively reviewed to evaluate long-term surgical outcomes. Possible risk factors for retethered cord syndrome (ReTCS) were evaluated in the long-term follow-up period.

METHODS

A total of 51 consecutive pediatric patients with LCMs who underwent a first untethering surgery and were followed for > 100 months were retrospectively analyzed. The surgery was performed with the partial removal technique. Pre- and postoperative clinical and radiological data were reviewed to analyze the outcomes of surgery and identify potential risk factors for ReTCS.

RESULTS

During follow-up, 12 patients experienced neurological deterioration due to ReTCS. The overall 10-year and 15-year progression-free survival rates were 82.3% and 75.1%, respectively. On univariate analysis, a lipoma type of lipomyelomeningocele (OR 11, 95% CI 2.50-48.4; p = 0.0014), patient age at the time of surgery (OR 0.41, 95% CI 0.14-1.18; p = 0.0070), and the mean patient growth rate after surgery (OR 2.00, 95% CI 1.12-3.41; p = 0.0040) were significant factors associated with ReTCS. Cox proportional hazard models showed that a lipoma type of lipomyelomeningocele (HR 5.16, 95% CI 1.54-20.1; p = 0.010) and the mean growth rate after surgery (HR 1.88, 95% CI 1.00-3.50; p = 0.040) were significantly associated with the occurrence of ReTCS.

CONCLUSIONS

More complex lesions and a high patient growth rate after surgery seemed to indicate increased risk of ReTCS. Larger prospective studies and registries are needed to define the risks of ReTCS more adequately.

Multimodality Imaging Evaluation of Fetal Spine Anomalies with Postnatal Correlation

Congenital anomalies of the spine are associated with substantial morbidity in the perinatal period and may affect the rest of the patient's life. Accurate early diagnosis of spinal abnormalities during fetal imaging allows prenatal, perinatal, and postnatal treatment planning, which can substantially affect functional outcomes. The most common and clinically relevant congenital anomalies of the spine fall into three broad categories: spinal dysraphism, segmentation and fusion anomalies of the vertebral column, and sacrococcygeal teratomas. Spinal dysraphism is further categorized into one of two subtypes: open spinal dysraphism and closed spinal dysraphism. The latter category is further subdivided into those with and without subcutaneous masses. Open spinal dysraphism is an emergency and must be closed at birth because of the risk of infection. In utero closure is also offered at some fetal centers. Sacrococcygeal teratomas are the most common fetal pelvic masses and the prognosis is variable. Finally, vertebral body anomalies are categorized into formation (butterfly and hemivertebrae) and segmentation (block vertebrae) anomalies. Although appropriate evaluation of the fetal spine begins with US, which is the initial screening modality of choice, MRI is increasingly important as a problem-solving tool, especially given the recent advances in fetal MRI, its availability, and the complexity of fetal interventions. Online supplemental material is available for this article. ^©RSNA, 2021.

Surgical histopathology of a filar anomaly as an additional tethering element associated with closed spinal dysraphism of primary neurulation failure

Background:

Closed spinal dysraphism of primary neurulation failure could be associated with filar anomalies, such as filar lipoma or thickened and tight filum terminale (TFT), resulting from impaired secondary neurulation. Retained medullary cord (RMC) is a remnant of the cavitary medullary cord originating from the secondary neurulation failure. Some filar lipomas are known to contain a central canal-like ependyma-lined lumen with surrounding neuroglial tissues (E-LC w/NGT), that is, a characteristic histopathology of RMC. To clarify the embryological background of these filar anomalies, we evaluated the histopathological findings.

Methods:

Among 41 patients with lesions of primary neurulation failure who underwent initial untethering surgery, the filum including cord-like structure (C-LS) was additionally resected in 10 patients (five dorsal and transitional lipomas; five limited dorsal myeloschisis). We retrospectively analyzed the clinical, neuroradiological, intraoperative, and histopathological findings.

Results:

Among 10 patients, two patients were diagnosed with RMC based on morphological features and intraoperative neurophysiological monitoring. The diagnosis of filar lipoma was made in six patients, since various amounts of fibroadipose tissue were histopathologically noted in the filum. Two patients were diagnosed with TFT, since the filum was composed solely of fibrocollagenous tissue. E-LC w/NGT was noted not only in both C-LSs of RMCs but also in two out of six fila both with filar lipomas and fila with TFTs.

Conclusion:

These findings provide further evidence for the idea that entities, such as filar lipoma, TFT, and RMC, can be considered consequences of a continuum of regression failure occurring during late secondary neurulation.

Does conus morphology have implications for outcome in lumbosacral lipoma?

OBJECTIVE

Lumbosacral lipomas (LSL) of the 'dorsal' type have been associated with more favourable outcomes compared with other conus region lipomas. We hypothesised that integrity of the conus on MRI underpins the improved prognosis in this subgroup of LSL patients.

METHODS

The definition of 'dorsal lipomas' included lipomas with attachment to the conus, but where the conus could be delineated on MRI (Morota type 1) as reported by Morota et al. (J Neurosurg Pediatr 19:428-439, 2017). Additional inclusion criteria included asymptomatic status at presentation, age >3 years at follow-up, and neurological and urological evaluation at presentation and at last follow-up. Lipoma extent and conus level were recorded. Outcome measures were the need for untethering surgery and neuro-urological status at last follow-up. Urological outcomes were defined by continence and efficacy of bladder emptying.

RESULTS

Twenty-six children were included (median age 8.7 years). Conus level was low (at or below L2) in 92%. Nine required untethering surgery: 5 prophylactic, 4 because of clinical deterioration. Twenty-five children were continent at last follow-up, one had stress incontinence, and none required catheterisation. One had persisting ankle weakness after surgery requiring orthotic support.

CONCLUSIONS

In LSL of the conus, visualisation of the conus on MRI is associated with good urological and motor outcomes. The integrity of the conus appears to be a more important prognostic factor than anatomical level. An observational approach to this group of LSL patients does not appear to compromise outcomes. These findings support a selective approach to untethering surgery.

Early- and long-term surgical outcomes in 109 children with lipomyelomeningocele

AIM

To determine the functional outcomes and risk factors for outcomes following surgery for lipomyelomeningocele (LMMC).

METHODS

Data from 109 children with LMMC who underwent surgery from January 2008 to December 2017 were retrospectively studied to evaluate functional outcomes and possible risk factors for early- (at discharge from hospital or within 1 month of surgery) and long-term outcomes after surgery.

RESULTS

There were 53 boys and 56 girls with median age of 36 months (IQR 12-90 months; range, 4 months to 18 years) at surgery. At presentation, neurological function was normal (asymptomatic group) in 28 (25.7%) children while there was neurological dysfunction (symptomatic group) in 81 (74.3%). Near total or radical excision of lipoma was done in 71 (65.1%) children. Six (5.8%) children had deterioration of neurological function in the post-operative period with recovery of function in three of them. There were no statistically significant risk factors for early outcomes. At a mean follow-up of 62.5 months (IQR 35-82 months; range, 12-146 months), 21 (27.6%) of the 76 symptomatic group children (including 59.3% with incomplete bladder dysfunction) showed improvement, 52 (68.4%) remained the same, while 3 (4%) deteriorated. In 31 children (symptomatic group) who developed symptoms after 1 year of age, early surgery after development of symptoms was associated with better chances of recovery (p = 0.0008). In the asymptomatic group, 23 (88.5%) had normal neurological function at mean follow-up of 57.5 months (IQR 30-77 months; range, 12-141 months) and 3 (11.5%) had neurological deterioration. The mean time to late deterioration (re-tethering) from surgery was 51.3 months (IQR 24-75 months; range, 24-84 months). Presence of syrinx on initial MRI (p = 0.008) and partial resection of the lipoma (p = 0.02) were independent risk factors for delayed deterioration.

CONCLUSION

Radical resection of LMMC probably helps in preserving neurological function in > 90% of children at long-term follow-up. Fifty-five percent of children > 2 years of age with incomplete bladder dysfunction regained normal function following surgery. In children who develop symptoms after birth, early surgical intervention can reverse the neurological deficits.

Familial tendency in patients with lipoma of the filum terminale

PURPOSE

Lipoma of the filum terminale (FL) is an abnormality in which fat is deposited in the filum terminale. This lipoma is often detected by skin abnormalities in the lumbosacral area such as a sacrococcygeal dimple. Some cases may develop tethered cord and become symptomatic. However, the genetic basis of FL is still unclear.

METHODS

This study aimed to determine whether there was a family history of FL or other forms of spina bifida among 54 families of 56 patients with FL and to examine whether there is a familial predisposition in FL. In addition, sex, age at diagnosis, presence of symptoms, presence of sacrococcygeal dimple, and the level of conus medullaris between familial and spontaneous cases were evaluated.

RESULTS

Of the 54 families of FL patients, there were 48 siblings. Among the 48 siblings, 2 had "occult" FL. The frequency of FL among siblings was estimated to be 4.2% (2/48), which was significantly higher than the sum of previously reported cases of spontaneous FL (0.91%; p = 0.017). However, there was no significant difference in sex, age at diagnosis, presence of symptoms, presence of sacrococcygeal dimple, diameter of filum terminale, or level of conus medullaris between familial and spontaneous cases.

CONCLUSION

To our knowledge, this is the first report on familial FL and examination of the frequency of FL among siblings. The high probability of FL among siblings of FL patients suggests that genetic factors may play a role in FL development.

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.

Intradural Conus Medullaris Lipoma With Neurological Deficit: A Rare Occurrence

Intradural lipoma without spinal dysraphism is a rare occurrence. Most of them are asymptomatic but can also present with neurological deficits. A 54-year-old male patient presented to us with progressive weakness in both lower limbs for six months. On physical examination and radiological workup, intradural lipoma was diagnosed. Due to progressive neurological deficit, the patient was treated surgically. On 2.5 years of follow-up, the patient showed complete neurological recovery. Intradural lipomas can also present with the neurological deficit at any age and should be managed surgically if the deficit is progressive in nature. Surgical management has a good outcome if done within two years of onset of symptoms.

External validation of a new classification of spinal lipomas based on embryonic stage

OBJECTIVE

Contention exists regarding appropriate classification and management of spinal lipomas (SLs). Given the heterogeneity of SLs, omissions and overlap between surgically incomparable groups exist in conventional classification systems. The new classification of spinal lipoma (NCSL) recently proposed by Morota et al. delineates morphology by embryological pathogenesis and the resultant operative difficulty. Here, the authors aimed to validate the NCSL by applying it to patients who had been operated on at their institution.

METHODS

All children who had undergone resection for SL between 2014 and 2018 were included in this analysis. MRI studies were independently reviewed and classified by three adjudicators. Baseline characteristics, inter-adjudicator agreement, coexisting anomalies and/or malformations, and postoperative outcomes and complications were analyzed.

RESULTS

Thirty-six patients underwent surgical untethering for SL: NCSL type 1 in 5 patients (14%), type 2 in 14 patients (39%), type 3 in 4 patients (11%), and type 4 in 13 patients (36%). All classification was agreed on first assignment by the adjudicators. Radical or near-radical resection, which was attempted in all patients, was always possible in those with type 1 and 4 SL, but never in those with type 2 and 3 SL. Neurological stabilization and/or improvement were observed in all patients at the last follow-up.

CONCLUSIONS

The NCSL was found to be a logical and reproducible system to apply in this SL population. All cases were successfully classified with a high degree of inter-assessor agreement. Widespread establishment of a commonly adopted and clinically useful classification system will enable clinicians to improve patient selection as well as discussion with patient representatives during the decision-making process.

Structured MRI reporting in spinal dysraphism

Magnetic resonance evaluation of spinal dysraphism can be confusing for inexperienced radiologists and a detailed, step-by-step evaluation of the normal and abnormal imaging findings can help garner the diagnosis. The purpose of this article is to review the existing literature and to provide a comprehensive, structured, template checklist-style format for reporting spinal dysraphism that can help inexperienced radiologists to systematically analyze and report all the significant and ancillary findings in cases of spinal dysraphism and efficiently communicate the findings to the treating physician/surgeon.

Cervical Lipomyelomeningocele Presenting with Progressive Motor Deficit: A Case Report and Review of the Literature

Cervical lipomyelomeningocele is a very rare form of spina bifida occulta, which can cause some complications following tethered cord syndrome. We report a 10-year-old female with a history of progressive upper-extremity weakness, a very small soft-tissue mass at the posterior aspect of her neck, and evidence of lipomyelomeningocele in her radiological study. The patient underwent laminectomy of C6 and C7 together with resection of lipomatous tissue attaching to the cord from superficial tissue and cord untethering, which resulted in progressive improvement of her weakness.

Long-term urological outcomes of spinal lipoma after prophylactic untethering in infancy: real-world outcomes by lipoma anatomy

STUDY DESIGN

Cohort study.

OBJECTIVES

Long-term urological outcomes in patients with spinal lipoma after prophylactic tethered cord release (TCR) in infancy were investigated.

SETTING

Children's hospital in Yokohama, Japan.

METHODS

Children under one year of age with spinal lipoma who underwent TCR between 1990 and 2010 were investigated. According to Arai's classification, lipomas other than filar lipoma were classified into four types: caudal, dorsal, transitional, and lipomyelomeningocele. The level of the conus medullaris was divided into three categories: L3-5, L5/S1, and sacral. Urological outcomes, including the need for clean intermittent catheterization (CIC), urinary incontinence, presence of renal deterioration, and the need for bladder augmentation, were investigated by both lipoma type and level of the conus medullaris.

RESULTS

Fifty-three patients met the inclusion criteria. The median follow-up period was 14.2 years (interquartile range 9.6-17.6 years). Of the 53 patients, ten (19%) were on CIC, and six (11%) were incontinent. Overall, two patients (4%) had renal deterioration detected by DMSA renal scan, and two (4%) needed augmentation cystoplasty. Of the lipoma types, transitional type showed the worst outcomes with respect to need for CIC (54%) and urinary incontinence (38%). There were no significant differences in renal deterioration and the rate of bladder augmentation by lipoma type. No urological outcomes were significantly associated with conus level.

CONCLUSIONS

Even after prophylactic TCR in infancy in children with spinal lipoma, 19% of patients needed CIC in long-term follow-up. Of the lipoma types, transitional type showed the worst outcomes with respect to need for CIC and urinary incontinence.

Whole spine MRI is not required in investigating uncomplicated paediatric lumbosacral lipoma. A retrospective single-institution review

PURPOSE

Lumbosacral lipoma (LSL) is a severe occult spinal dysraphism, frequently associated with neurological, urological and orthopaedic complications. Whole spine imaging is typically performed to identify concomitant, but spatially separate, congenital anomalies. Our hypothesis: the incidence of additional, clinically significant abnormalities of the neuraxis is low; thus, imaging should be optimised at the lumbosacral region. We aim to assess the prevalence and relevance of LSL-associated lesions.

METHOD

A single-centre, retrospective, radiological review using a prospectively maintained operative database.

INCLUSION CRITERIA

children (< 16 years) with confirmed diagnosis of LSL and received whole spine MRI. Fatty filum, syndromic cases and cutaneous stigmata above lesion level were excluded. Data was extracted from radiological imaging, reports and clinical correspondence.

RESULTS

One hundred twelve patients (40:72, M:F) aged 0.5 years (0.2-2.7) (median ± IQR) with LSL had whole spine MRI between 2001 and 2017. Classification of LSL: transitional 48 (43%); dorsal 30 (27%); caudal 28 (25%) and chaotic 6 (5%). Additional anomalies included syringohydromyelia 44 (39%), subcutaneous tract 19 (17%), abnormal vertebral segmentation 18 (16%), dermoid cyst 1 and 1 Chiari I deformity. There were no Chiari II malformations. No child required surgery for an associated lesion. Binary logistic regression revealed no factors associated with predicting secondary lesions.

CONCLUSIONS

In congenital LSL, additional anomalies of the neuraxis are typically loco-regional rather than pan-CNS and additional lesions are rarely clinically significant. The loco-regional distribution of anomalies suggests that only lumbosacral spinal imaging is required in the initial evaluation of LSL. Such a policy would lessen the anaesthetic/sedation time for children and reduce imaging cost per patient. MRI protocols could be refined to optimise imaging quality at the region of interest.

Radical excision of lumbosacral lipoma: an early experience of "followers"

BACKGROUND

Indication, timing, and method for surgical treatment of lumbosacral lipoma are controversial. Radical resection of the lumbosacral lipoma and complete reconstruction of the placode are supported in that better long-term outcome can be achieved without increasing complication rate compared with traditional surgical techniques.

OBJECTIVE

We analyzed the early surgical outcomes of lumbosacral lipoma treated with the untethering and radical excision of fat.

METHODS

Retrospective analysis of surgically treated 81 fresh lumbosacral lipoma cases with dorsal, transitional, and chaotic types and true lipomyelomeningocele (LMMC) was performed. Caudal and filar types were excluded.

RESULTS

Complete untethering was accomplished in 98%. Radical excision of the lipoma was attempted in all cases and achieved in 83%. Postoperative neurological complication was observed in 8 cases (10%). Group of lipoma types (dorsal + transitional vs. chaotic + true LMMC) and availability of radical lipoma excision turn out to be factors related to neurological outcomes in univariate analysis (p < 0.001 and p = 0.027, respectively). Group of lipoma types, availability of radical excision, and postoperative cord/dural sac (C/D) ratio are related factors in multivariate analysis (p = 0.025, p = 0.049, and p = 0.031).

CONCLUSIONS

As a follower of untethering and radical excision of fat, careful consideration is required to plan the surgery of lumbosacral lipoma on account of the "underestimated" complication rate. Type of the lipoma is the important factor determining the surgical outcome. Availability of complete radical excision and postoperative C/D ratio are the operative factors related to the neurological outcomes.

Acute presentations of intradural lipomas: case reports and a review of the literature

BACKGROUND

Lumbosacral lipomas (LLs) may remain asymptomatic or lead to progressive neurological deterioration. However, sudden neurological deterioration is a rare and severe event. Herein, we report rare occurrences of sudden clinical deterioration in two previously asymptomatic children harbouring intradural LLs without dermal sinus tracts or signs of occult dysraphism. A review of the pertinent literature is also included.

CASE PRESENTATION

One child exhibited acute deterioration because of an epidural abscess associated with a filar lipoma without a sinus tract (probably caused by haematogenous spreading from a respiratory tract multiple infection), and the other child exhibited acute deterioration because of a very large, holocord syringomyelia-like cyst associated with a small conus lipoma. Both patients were 4 years old. In case #2, a previously undetected, severe tethered cord (conus at the S3-S4 level) was also present. A complete recovery was attained after an urgent surgical operation in both cases (in addition to targeted antibiotic therapy in case #1). All cases of deterioration in the literature were caused by abscess formation in dermal sinus tracts.

CONCLUSIONS

Prophylactic surgery may be indicated even in asymptomatic children that have tethered cord and surgically favourable LLs (small dorsal and filar LLs), especially if the conditions are associated with progressive syringomyelia. Similarly, intradural dermal sinus tracts should be regarded as surgery-indicated, even if the conus is in its normal position and the patient is asymptomatic because there is a consistent risk of severe, infection-related complications. Finally, asymptomatic patients with filar LLs and a normally located conus can be candidates for surgery or an accurate clinical and radiological follow-up.

Ependyma-Lined Canal with Surrounding Neuroglial Tissues in Lumbosacral Lipomatous Malformations: Relationship with Retained Medullary Cord

BACKGROUND

An ependyma-lined canal with surrounding neuroglial tissues can be present in lumbosacral lipomatous malformations; however, the precise embryological significance is still unclear.

METHOD

Six out of 50 patients with lipomatous malformations had ependymal structures. We retrospectively analyzed the clinical, neuroradiological, and histological findings of these patients to demonstrate the relationship with the embryological background of the retained medullary cord (RMC), which normally regresses, but was retained here because of late arrest of secondary neurulation.

RESULTS

Five (13.9%) of 36 patients with filar and caudal types and 1 of 3 lipomyelomeningoceles had ependymal structures, while none with dorsal and transitional types had these tissues. Histologically, the ependymal structures surrounded by neuroglial tissue and containing various amounts of adipose tissue bear a striking resemblance to the ependymal structures in RMC.

CONCLUSION

The 13.9% incidence of association between the ependymal structures and filar and caudal types is thought to be because of second ary neurulation failure with the same embryological background as that of RMC. Dorsal and transitional types, resulting from primary neurulation failure, therefore, did not have ependymal structures.

Spinal arteriovenous fistula coexisting within a spinal lipoma: report of two cases

INTRODUCTION

Spinal lipoma and spinal arteriovenous fistula (sAVF) are different pathologies and their co-existence is extremely rare. Here we reported two cases of adult-onset sAVF occurring within a spinal lipoma and with review the literature in an attempt to identify the mechanisim of and optimal treatment of this condition.

CASE PRESENTATION

Case 1 was a 51-year-old man who was treated by embolization of the feeding artery and ligation of the draining vein. Case 2 was a 53-year-old man who was treated by embolization and resection of the tumor containing the shunt zone. In both cases, symptoms improved after surgery. However, in Case 1, angiography at 1 month after the surgery revealed recurrence of the arteriovenous shunt.

DISCUSSION

A literature search revealed only nine other similar case reports. All cases, including ours occurred in adults. In almost all cases, the shunt was located within the spinal lipoma. Pathologic examination revealed venous hypertension, but no evidence of congenital vascular malformation. Given that lipomas release angiogenic factors, the presence of a spinal lipoma may indicate its involvement in the development of acquired sAVF. Our two cases might represent a new subtype of sAVF. Based on our experiences, we recommend resection of the tumor containing the shunt for the management of sAVF.

Lateral lipomyelomeningocele of the hemicord with split cord malformation type I revealed by 3D heavily T2-weighted MR imaging

BACKGROUND

Lipomyelomeningocele (LMMC) is defined by a low-lying tethered spinal cord protruding posteriorly from the spinal canal and terminating in a lipomatous mass in the subcutaneous meningeal sac. The coexistence of LMMC with split cord malformation (SCM) is rare.

CLINICAL PRESENTATION

We report on a patient with laterally protruded LMMC arising from the hemicord of SCM type I. Direct coronal and axial views (instead of sagittal views) of 3D heavily T2-weighted MR imaging (3D-hT2WI) clearly demonstrated the topographical relationship between both of the hemicords, the bony septum, and nerve roots in the right subcutaneous meningeal sac.

CONCLUSION

Combined use of axial and coronal images of 3D-hT2W is useful for visualization and surgery of such a complicated anomaly.

Minimally invasive endoscopic spinal cord untethering: case report

Tethered cord syndrome is a constellation of symptoms and signs that include back and leg pain, bowel and bladder dysfunction, scoliosis and lower extremity weakness and deformity. Tethering may be due to a tight filum terminale or a form of spinal dysraphism. The authors present a case of a 40-year-old man who presented with symptoms of back pain, bilateral lower extremity radicular pain, and bowel and bladder dysfunction. Magnetic resonance imaging showed a sacral lipomyelomeningocele, with fat tracking superiorly to the conus, which was tethered at the L4-L5 level. A minimally-invasive surgical approach with endoscopic visualization and identification of the nerve roots and filum terminale was performed. The patient's postoperative clinical course was uneventful. This case highlights two important issues. First, minimally invasive spine techniques should be considered in the surgical treatment of tethered cord especially given the theoretical advantages of minimizing pain, spinal fluid leakage, and subsequent scarring. And second, endoscopic techniques are advancing. In the case presented here, endoscopic visualization and operative techniques made identification and transection of the filum terminale possible through a tiny dural opening. The small dural opening could theoretically pose the advantage of decreasing the risk of spinal fluid leakage. Clinicians should be aware that endoscopic visualization and techniques can serve as minimally-invasive adjuncts to enhance the traditional approach to many surgical pathologies.

New classification of spinal lipomas based on embryonic stage

OBJECTIVE Spinal lipomas are generally thought to occur as a result of failed primary neurulation. However, some clinical features cannot be explained by this theory. The authors propose a novel classification of spinal lipomas based on embryonic changes seen during primary and secondary neurulation. METHODS A total of 677 patients with occult spinal dysraphism underwent 699 surgeries between August 2002 and May 2015 at the National Center for Child Health and Development and Tokyo Metropolitan Children's Medical Center. This group of patients had 378 spinal lipomas, including 119 conus spinal lipomas, 27 lipomyelomeningoceles, and 232 filum lipomas, which the authors classified into 4 types based on neural tube formation during embryonic development. Type 1 is defined as pure primary neurulation failure; Type 2 ranges from primary to secondary neurulation failure; Type 3 consists of secondary neurulation failure (early phase); and Type 4 is defined as secondary neurulation failure (late phase). The authors also review embryogenesis in secondary neurulation and analyze the clinical utility of the new classification. RESULTS There were 55 Type 1 spinal lipomas, 29 Type 2, 62 Type 3, and 232 Type 4. All filum lipomas fell into the Type 4 spinal lipoma category. Association with anorectal and/or sacral anomalies was seen in none of the Type 1 cases, 15 (52%) of Type 2, 35 (56%) of Type 3, and 31 (13%) of Type 4. Urogenital anomalies were observed in none of the Type 1 or Type 2 cases, 1 (2%) of Type 3, and 28 (12%) of Type 4. Anomaly syndromes were present in none of the Type 1 cases, 6 (21%) of Type 2, 3 (5%) of Type 3, and 16 (7%) of Type 4. Associated anomalies or anomaly syndromes were clearly observed only for Type 2-4 spinal lipomas encompassing failed secondary neurulation. Radical resection was feasible for Type 1 spinal lipomas. CONCLUSIONS Secondary neurulation of the spinal cord gives rise to the conus medullaris and filum terminale, which are often involved in spinal lipomas. Formation of spinal lipomas seems to be a continuous process overlapping primary and secondary neurulation in some cases. Association with other anomalies was higher in Type 2-4 spinal lipomas, which included failed secondary neurulation, than in Type 1 lipomas, with failed primary neurulation. On the other hand, radical resection was indicated for Type 1, but not for Type 2, spinal lipomas. The new classification of spinal lipomas based on embryonic stage has the potential for clinical use and agrees well with both clinical and surgical findings. The classification proposed here is still preliminary. Further studies and verification are necessary to establish its clinical utility.

Results of the prophylactic surgery of lumbosacral lipomas 20 years of experience in the Paediatric Neurosurgery Department La Timone Enfants Hospital, Marseille, France

We conducted a retrospective study of children with lumbosacral lipomas treated in the Department of Pediatric Neurosurgery hospital Timone Enfants in the last 20 years. We selected patients with lipomas of the conus medullaris who underwent preventive surgery. 86 ,4 % of the patients remained asymptomatic during the follow-up. Worse results were observed in children older than one year old at surgery with transitional lipoma, with the conus medullaris was below L5 and when the resection had been partial. In view of the results, the authors recommend the preventive surgery before the first year of life under neurophysiologic monitoring in order to perform a total near-total resection with a neural plate reconstitution.

Surgical treatments on adult tethered cord syndrome: A retrospective study

To investigate effects of surgical treatment on adult tethered cord syndrome (TCS).A retrospective analysis of 82 adult patients (17 male cases, 82% and 24 female cases, 59%) with TCS treated by surgery was conducted between March, 2005 and December, 2015, with an average age of 31.6 years and average disease course of 6.7 years. All the 82 cases of patients received nerve electrophysiology monitoring assisted microsurgery. After surgery, all patients were followed up for an average of 2.5 years. Surgical effects were evaluated according to Hoffman grading system. As this is just a retrospective study that does not involve any interventions, ethical approval was not necessary according to the rules of the hospital.All patients were followed up, no death occurred. According to Hoffman grading system, the neurologic symptoms were improved in 22 patients (27%), stabilized in 60 patients (73%). Of 10 cases with lipoma tethered spinal cord, corresponding symptoms were improved in 2 cases. Of 32 cases with tethered spinal cord caused by dermoid cyst and epidermoid cyst, the symptoms were improved in 6 cases. Of 40 cases without occupying lesions of tethered spinal cord, the symptoms were improved in 14 cases. Besides, there was no deteriorated case.Surgical treatment on adult patients with TCS can improve the neurologic deficits which are associated with the course of disease, early treatment has much better curative effect.

Immediate and long-term outcome analysis of lipomeningomyelocele repair in asymptomatic infants in a tertiary care center

Objective:

To analyze immediate and long-term results of lipomeningomyelocele (LMM) repair in asymptomatic patients.

Materials and Methods:

Seventeen patients of LMM presented to Department of Paediatric Surgery over a period from 2011 to 2015 were evaluated preoperatively by magnetic resonance imaging of whole spine, and pre- and post-operative Ultrasound of kidney, ureter, bladder, and neurosonogram. Surgical procedure involved total excision of lipoma in 15 patients and near total excision in 2 patients. Division of filum terminale could be done in 15 out of 17 patients. Follow-up varied from 1 to 3.5 years (mean 1.9 years).

Results:

This study included 10 (58.8%) patients of lumbosacral LMM, 5 (29.4%) patients of sacral, and 2 (11.7%) patients of thoracolumbar LMM. About 13 (76.4%) patients were operated before 3 months of age, 2 (23.5%) patients were operated between 3 and 6 months, and two patients were operated between 6 and 11 months. None of the patients had bladder/bowel dysfunction preoperatively. Preoperative lower limb power was normal in all patients. Objective improvement in lower limb motor function was observed in 3 (17.6%) patients and three patients had decreased lower limb power. Two patients developed altered sensations and weakness of lower limb about 2.5-3 years after initial LMM repair. They needed repeat detethering of cord. Two patients had fecal pseudoincontinence, whereas one patient developed constipation. Bowel dysfunction was managed by rectal washouts, and oral laxatives were added if required. One (5.8%) patient of lumbosacral LMM and 1 (5.8%) patient of sacral LMM had urinary incontinence postoperatively. This was managed by clean intermittent catheterization with continuous overnight drainage. Conservative management of bladder and bowel dysfunction was effective in all patients till the last follow-up. Two patients developed hydrocephalus after LMM repair for which low-pressure ventriculoperitoneal shunt was inserted. Wound infection occurred in 1 (5.8%) patient, whereas 7 (41.1%) patients developed seroma in wound which responded to repeated aspirations under aseptic precautions.

Conclusion:

With total excision of lipoma and division of filum terminale satisfactory outcome for asymptomatic patients of LMM can be achieved. Authors recommend early surgery for LMM even in asymptomatic patients. Patients with residual lipoma and undivided filum terminale should be observed closely for the development of progressive neurological changes.

The natural history and management of patients with congenital deficits associated with lumbosacral lipomas

INTRODUCTION

Many patients with lumbosacral lipoma are asymptomatic; however, a significant proportion will have neurological deficits present at birth. Implication of these deficits with respect to natural history and management are not well understood.

METHODS

A retrospective review of all infants with lumbosacral lipoma seen at BCCH between 1997 and 2013 was carried out. The study population was stratified on the presence of a congenital, non-progressive deficit and subdivided on treatment approach. The subsequent developments of deficits resulting in untethering procedures were recorded.

RESULTS

Of the 44 infants in this study, 24 patients had no neurologic deficit while 20 patients had a fixed, non-progressive deficit evident at birth. Ten of 24 patients without a neurological deficit at birth underwent a prophylactic untethering with 3 eventually requiring repeat untethering after, on average, 62.7 months. Eleven of 14 asymptomatic, monitored patients required untethering for clinical deterioration. Two required a second untethering procedure after 48.7 months. Ten of 20 infants with congenital deficits present at birth underwent prophylactic untethering, and 4 required further surgery after 124 months. Ten patients underwent observation with 8 eventually requiring surgery. Two required repeat untethered after 154 months. The complication rates and operative burden for patients are similar whether prophylactic or delayed surgery is performed.

CONCLUSION

The presence of congenital neurologic deficit does not affect the likelihood of deterioration in patients managed expectantly; prophylactic detethering of these patients did not prevent delayed neurologic deterioration. Comparing the need for repeat surgery in prophylactically untethered patients with initial untethering of patients operated upon at the time of deterioration, prophylactic untethering may confer a benefit with respect to subsequent symptomatic tethering if complication rates are low. However, in a setting with multidisciplinary follow-up, a period of observation for patients and intervention when patients become symptomatic is an acceptable approach for patients with or without congenital deficits.

Symptomatic retethering of the spinal cord in postoperative lipomyelomeningocele patients: a meta-analysis

BACKGROUND

Timing of surgical treatment for tethered cord syndrome due to a lipomyelomeningocele (LMM) has been controversial. The purpose of this study was to evaluate populations of patients treated surgically for LMM in a meta-analysis in order to better understand how outcomes differ based on follow-up time, symptomatology, and LMM classification.

METHODS

An extensive search on PubMed and Google Scholar was performed for LMM and surgical outcomes to identify case series of patients for inclusion in this analysis. Patients were sorted based upon symptomatology prior to surgery and Chapman's LMM classification, where possible. Deterioration rates were determined by symptomatic retethering of the spinal cord that led to repeat surgery.

RESULTS

Of 608 (19 %) patients, 115 were included in the study experienced deterioration leading to repeat surgery. Symptomatic and asymptomatic patients did not experience significantly different rates of deterioration after surgical untethering. There was a significant positive linear correlation between follow-up time of studies and percentage of patients deteriorating with an increase of 3.3 % per year of follow-up. Transitional LMM had a significantly higher rate of deterioration compared to the caudal type along with the entire patient pool.

CONCLUSIONS

Outcomes of primary surgical treatment in regard to late deterioration are not significantly affected by patient symptomatology. Patient deterioration increases linearly over time. Additional studies should be performed to adequately determine the natural history of asymptomatic patients that are treated conservatively for LMM.

The value of intraoperative neurophysiological monitoring for microsurgical removal of conus medullaris lipomas: a 12-year retrospective cohort study

Background

Lipomas in the lower spinal canal can lead to progressive neurological deficits, so they may have to be surgically removed. Intraoperative neurophysiological monitoring serves to minimize the morbidity of the surgical procedure. However, so far there are no evidence-based recommendations which type of monitoring procedure or combination of procedures to choose.

Methods

The aim of this study was to evaluate the feasibility and value of various intraoperative monitoring techniques: motor and sensory evoked potentials (MEP, SEP), free-running and triggered electromyography (EMG). Thirty cases of spinal lipomas of the Conus medullaris (dorsal Type A: 20.0%; caudal Type B: 33.3%; transitional Type C: 46.7%) were retrospectively evaluated over a 12-year period.

Results

The patients were mostly pediatric and suffered from persistent pain (73.3%), pareses (56.7%), sensory deficits (43.4%), and/or urogenital dysfunctions (60.0%). SEPs were successfully evoked in 66.7% of cases, MEPs in 86.7% of cases, and EMGs in 100%. MEP alterations correlated with direct mechanical maneuvers in the operating site. SEP changes correlated mostly with physiological events, such as rinsing/cooling of the operating site. Spike-, burst- or tonic train-activity was found in the free-running EMG that occurred only with certain manipulation patterns. Irreversible MEP changes and signal loss in the triggered EMG correlated with post-operative deficits.

Conclusions

The results of this study showed, that intraoperative monitoring could be considered a helpful tool during lipoma tumor surgery near the Conus medullaris. Most reliable results were obtained from transcranial MEPs, free-running EMGs, and triggered EMGs. That’s why the authors favor a routine set-up consisting of at least these three techniques, as this enables mapping at the beginning of the operation, continuous functional testing during surgery, and prognosis of the post-operative symptomology.

Asymptomatic lipomas of the medullary conus: surgical treatment versus conservative management

OBJECT

The goal of this study was to compare long-term results of surgery with the outcomes of conservative treatment in patients with asymptomatic lipomas of the conus medullaris.

METHODS

The parents of 56 consecutive children with a diagnosis of asymptomatic lipoma of the conus medullaris underwent detailed neurosurgical consultation. The pros and cons of both prophylactic surgery and conservative treatment were carefully presented. Both options were offered, and the parents were free to choose the preferred management. A total of 32 children underwent surgical treatment, and 24 were conservatively treated. Afterward, all patients entered the same protocol of serial neurological and urological follow-up at the Centro Spina Bifida. The mean follow-up periods were 9.7 years in the surgical treatment group and 10.4 years in the conservative treatment group.

RESULTS

Permanent surgical morbidity was 3.1% (1 patient). During follow-up, tethered cord syndrome occurred in 9.7% of the surgically treated patients (3 of 32 patients) and in 29.1% of the conservatively managed children (7 of 24 patients). This difference did not result in statistical significance, but a clear trend in favor of surgery emerged. Young age at surgery and a cord/sac ratio < 50% appeared to be determining factors in the prevention of subsequent tethered cord syndrome.

CONCLUSIONS

The small size of this series does not provide enough statistical evidence that surgical treatment can really improve the natural history of asymptomatic lipomas of the conus medullaris. Nevertheless, surgery appears at least advisable since it reduces by 75% the odds of TCS (p = 0.067), which is quite close to statistical significance.

Filum terminale lipomas: imaging prevalence, natural history, and conus position

OBJECT

Filum terminale lipomas (FTLs) are being identified with increasing frequency due to the increasing utilization of MRI. Although an FTL may be associated with tethered cord syndrome (TCS), in many cases FTLs are diagnosed incidentally in patients without any symptoms of TCS. The natural history of FTLs is not well defined.

METHODS

The authors searched the clinical and imaging records at a single institution over a 14-year interval to identify patients with FTLs. For patients with an FTL, the clinical records were reviewed for indication for imaging, presenting symptoms, perceived need for surgery, and clinical outcome. A natural history analysis was performed using all patients with more than 6 months of clinical follow-up.

RESULTS

A total of 436 patients with FTL were identified. There were 217 males and 219 females. Of these patients, 282 (65%) were adults and 154 (35%) were children. Symptoms of TCS were present in 22 patients (5%). Fifty-two patients underwent surgery for FTL (12%). Sixty-four patients (15%) had a low-lying conus and 21 (5%) had a syrinx. The natural history analysis included 249 patients with a mean follow-up time of 3.5 years. In the follow-up period, only 1 patient developed new symptoms.

CONCLUSIONS

Filum terminale lipomas are a common incidental finding on spinal MRI, and most patients present without associated symptoms. The untreated natural history is generally benign for asymptomatic patients.

Alteration in radiological subtype of spinal lipoma: case report

We experienced a rare case of lipomyelomeningocele diagnosed at birth by magnetic resonance imaging which transformed the radiological appearance after 2 months into the transitional-type spinal lipoma with rapid increase in size of lipoma. Intraoperative findings revealed the presence of the dural sac extended dorsally outside the vertebral canal, which was characteristic of lipomyelomeningocele. Although there have been several reports showing that the size of spinal lipoma changed during development, there have been no reports which demonstrated alteration of radiological subtype with rapid increase of lipoma. Herein, we describe the first case of lumbosacral lipoma which changed radiological subtype from lipomyelomeningocele into transitional-type spinal lipoma.

Usefulness of three-dimensional T1-weighted spoiled gradient-recalled echo and three-dimensional heavily T2-weighted images in preoperative evaluation of spinal dysraphism

PURPOSE

The aim of this study was to evaluate the usefulness of three-dimensional T1-weighted spoiled gradient-recalled echo (3D T1-GRE) images for the preoperative anatomical evaluation of lumbosacral lipoma, thick filum terminale, and myelomeningocele as a means of compensating for the drawbacks of 3D heavily T2-weighted (3D hT2-W) images.

METHODS

Nine patients with lumbosacral lipomas, one patient with tight filum terminale, and five patients with myelomeningoceles were included in this study. 3D T1-GRE images were compared with 3D hT2-W images or conventional magnetic resonance images in terms of delineation of lipomas and other structures in the patients with lipomas and tight filum terminale. For patients with myelomeningoceles, 3D T1-GRE images were compared with 3D hT2-W images in terms of artifacts in the cerebrospinal fluid (CSF) space.

RESULTS

The 3D T1-GRE images demonstrated lipomas with good contrast to the spinal cord and CSF space and more clearly delineated the anatomical relationship between lipomas and these structures than did the 3D hT2-W images. The 3D T1-GRE images delineated dural defects through which extradural lipomas penetrated into the intradural space. The 3D T1-GRE images also demonstrated the presence or absence of lipomas in the filum terminale and the absence of artifact in the myelomeningoceles. Furthermore, they were useful for differentiating artifacts observed on the 3D hT2-W images from nerve elements.

CONCLUSIONS

The complementary use of 3D T1-GRE and 3D hT2-W images may compensate for the drawbacks of 3D hT2-W images and may eventually improve lesion visualization and surgical decision making.