Conservative Management of Asymptomatic Spinal Lipomas of the Conus

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

Neurophysiological identification and differentiation between the motor and sensory roots in pediatric spinal cord lipoma surgery

BACKGROUND

Radical resection of spinal cord lipomas reduces the rate of re-tethering. Current conventional neurophysiological mapping techniques are not able to differentiate between crucial motor nerve roots and sensory roots. Enhanced differentiation could contribute to complete resection. We present our experience with a double-train paradigm to differentiate between motor and sensory roots.

METHODS

In children undergoing spinal cord lipoma resection, the double-train mapping paradigm was used with an inter-train interval of 60 ms. Given the longer recovery time due to the H-reflex, a single muscle response was presumed to be elicited from a sensory root, and a double muscle response from a motor root. The primary endpoint was postoperative neurological outcome and bladder function at discharge.

RESULTS

We included 8 children undergoing 10 lipoma resections between 2016 and 2023. Double-train mapping was used in all cases. Motor and sensory roots were clearly differentiated in 6 cases and altered the course of surgery in 4 cases. Post-surgery, no sensory and motor function worsened within 3 months. Bladder function was stable in six and improved in two children. In two patients, bladder function worsened slightly at 3 months and 6 months, at which point one patient was re-operated on for re-tethering.

CONCLUSION

Intraoperative mapping with the double-train paradigm reliably differentiated between motor and sensory nerve roots. Informing the surgeon on the specific function of a tethering root may help to maximize resection without risking major neurological deficits.

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.

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.

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.

Diagnosis and Management of Tethered Cord Syndrome

Tethered cord syndrome is a condition in which the spinal cord is tethered by pathological structures such as a tight filum terminale, intradural lipomas with or without a connecting extradural component, intradural fibrous adhesions, diastematomyelia, and neural placode adhesions following closure of a myelomeningocele.It usually occurs in childhood and adolescence as the spine grows in length, but it can also develop in adulthood. Symptoms of tethered cord syndrome are slowly progressive and varied. Incorrect diagnosis and inappropriate treatment may be provided if the physician lacks knowledge and understanding of this disease.This chapter aims to describe the pathophysiology, syndromes, diagnostic imaging, surgical treatment, and prognosis of tethered cord syndrome to enhance the understanding of this condition.

Intraoperative neurophysiology in pediatric neurosurgery: a historical perspective

INTRODUCTION

Intraoperative neurophysiology (ION) has been established over the past three decades as a valuable discipline to improve the safety of neurosurgical procedures with the main goal of reducing neurological morbidity. Neurosurgeons have substantially contributed to the development of this field not only by implementing the use and refinement of ION in the operating room but also by introducing novel techniques for both mapping and monitoring of neural pathways.

METHODS

This review provides a personal perspective on the evolution of ION in a variety of pediatric neurosurgical procedures: from brain tumor to brainstem surgery, from spinal cord tumor to tethered cord surgery.

RESULTS AND DISCUSSION

The contribution of pediatric neurosurgeons is highlighted showing how our discipline has played a crucial role in promoting ION at the turn of the century. Finally, a view on novel ION techniques and their potential implications for pediatric neurosurgery will provide insights into the future of ION, further supporting the view of a functional, rather than merely anatomical, approach to pediatric neurosurgery.

The evolution of pediatric neurosurgery: reflection of personal experience of the last half-century

OBJECTIVES

In the past 50 years, pediatric neurosurgery has made tremendous strides, and gained its own identity as a distinct subspecialty. I have personally observed this progress and evolution in pediatric neurosurgery in multiple dimensions, which are described based upon my own experience and reflection.

METHODS

The development and evolutions of multiple domains of pediatric neurosurgery, including neuroimaging, hydrocephalus, pediatric brain tumor, spinal dysraphism, craniosynostosis, vascular malformation, functional neurosurgery and spinal disorders were reviewed and commented on based upon my own experience and reflection.

RESULTS

The field of pediatric neurosurgery has grown in all aspects of diagnosis and therapy owing to the introduction of computers, innovative techniques and technologies and new discoveries of scientific data including molecular investigations.

CONCLUSION

A minimally invasive approach and molecular target therapy are a current trend. The past half century's clinical experience and advances in biomedical knowledge and techniques provide foundation for further improvement in the care of children of the next generation. Prospective artificial intelligence will likely promote further advances in pediatric neurosurgery.

Motor-evoked potential monitoring from urinary sphincter muscle during pediatric untethering surgery: a case series

PURPOSE

Postoperative urinary dysfunction following untethering surgery for spinal lipoma is devastating. To assess urinary function, we invented a pediatric urinary catheter equipped with electrodes for the direct transurethral recording of myogenic potential from the external urethral sphincter (EUS). This paper presents two cases in which urinary function was monitored intraoperatively by recording of motor-evoked potential (MEP) from EUS during untethering surgery in children.

METHODS

Two children (aged 2 and 6 years) were included in this study. One patient had no preoperative neurological dysfunction, while the other had frequent urination and urinary incontinence. A pair of surface electrodes was attached to a silicone rubber urethral catheter (6 or 8 Fr; diameter, 2 or 2.6 mm). The MEP from the EUS was recorded to assess the function of the centrifugal tract from the motor cortex to the pudendal nerve.

RESULTS

Baseline MEP waveforms from the EUS were successfully recorded with latency and amplitude of 39.5 ms and 66 µV in patient 1 and 39.0 ms and 113 µV in patient 2, respectively. A significant decrease in amplitude was not observed during surgery in the two cases. No new urinary dysfunction and complications associated with the urinary catheter-equipped electrodes developed postoperatively.

CONCLUSION

Using an electrode-equipped urinary catheter, monitoring of MEP from the EUS could be applicable during untethering surgery in pediatric patients.

Nephrogenic rest vs immature teratoma associated with lumbosacral lipomyelomeningocele: a case report and review of the literature

BACKGROUND

Lipomyelomeningoceles (LMMs) are subcutaneous lipomas with dural penetration that often present with spinal cord tethering and may lead to neurological deterioration if untreated. This report describes a rare case of an LMM associated with immature nephroblastic tissue, representing a nephrogenic rest (NR) or, less likely, an immature teratoma.

CLINICAL PRESENTATION

An 8-day-old infant girl presented to the clinic with a sacral dimple. Imaging demonstrated a tethered spinal cord with low-lying conus medullaris and an LMM. A firm mass was noted in the subcutaneous lipoma. Detethering surgery and removal of the lipoma and mass were performed at the age of 6 months. Pathological examination identified the mass as cartilage, fat, and immature nephroblastic tissue consistent with NR tissue or, less likely, a teratoma with renal differentiation.

CONCLUSION

This presentation of an LMM associated with an immature teratoma or NR poses a risk of malignant transformation in patients. As a result, careful surgical dissection, resection, and close clinical follow-up are recommended for these patients.

Transition from partial to near-total/radical resection of spinal cord lipomas

PURPOSE

The objective of this retrospective study was to compare the outcomes and associated complication rates in the surgical management of spinal cord lipomas following a change of practice within our institution from partial resection (PR) to near-total/radical resection (NTR).

METHODS

Twenty-four children underwent surgical treatment for symptomatic spinal cord lipomas between 2009 and 2020. The near-total/radical resection group included 20 patients with spinal cord lipomas and the comparison group included 6 patients with spinal cord lipomas who underwent partial resection. Filar lipomas were excluded.

RESULTS

The mean age of the patients was 7 years (range 1-14 years). Post-operatively, a higher proportion of NTR patients (17/20, 85%) demonstrated improvement or stabilisation in Necker-Enfants Malades scores compared to PR patients (3/6, 50%) with a mean follow-up of 48 and 108 months respectively. Two patients underwent re-do untethering surgery, both of which initially underwent partial resection surgery. Complication rates did not significantly differ between the two groups.

CONCLUSION

Our data supports the view that near-total/radical resection should be considered the technique of choice over the conventional method of partial resection for spinal cord lipomas with no significant increase in complication rates.

First Trimester Ultrasound Detection of Fetal Central Nervous System Anomalies

OBJECTIVE

To evaluate the potential of the first-trimester ultrasound (US) features for the detection of central nervous system (CNS) anomalies. Methods/Methodology: This is a prospective one-center three-year study. Unselected singleton pregnant women were examined using an extended first-trimester anomaly scan (FTAS) that included the CNS assessment: the calvaria shape, the septum (falx cerebri), the aspect of the lateral ventricles, the presence of the third ventricle and aqueduct of Sylvius (AS) and the posterior brain morphometry: the fourth ventricle, namely intracranial translucency (IT), brain stem/brain stem-occipital bone ratio (BS/BSOB) and cisterna magna (CM). The spine and underlying skin were also evaluated. The cases were also followed during the second and third trimesters of pregnancy and at delivery. FTAS efficiency to detect major CNS abnormalities was calculated.

RESULTS

We detected 17 cases with CNS major abnormalities in a population of 1943 first-trimester (FT) fetuses, including spina bifida with myelomeningocele, exencephaly-anencephaly, holoprosencephaly, hydrocephaly, cephalocele and Dandy-Walker malformation. The CNS features in the abnormal group are presented. In the second trimester (ST), we further diagnosed cases of corpus callosum agenesis, cerebellar hypoplasia, vein of Galen aneurysm and fetal infection features (ventriculomegaly, intraventricular bands, intraventricular cyst and hyperechoic foci), all declared normal at the FTAS. During the third trimester (TT) scan we identified a massive fetal cerebral haemorrhage absent at previous investigations. We report a detection rate of 72.7% of fetal brain anomalies in the FT using the proposed CNS parameters. The sensitivity of the examination protocol was 72.7%, and the specificity was 100%.

CONCLUSION

A detailed FT CNS scan is feasible and efficient. The majority of cases of major CNS abnormalities can be detected early in pregnancy. The visualization rates of the CNS parameters in the FT are great with short, if any, additional investigation time. FT cerebral disorders such as haemorrhage or infections were missed in the FT even when an extended evaluation protocol was used.

The Current Status of the Surgical Management of Complex Spinal Cord Lipomas: Still Navigating the Labyrinth?

This review summarises the classification, anatomy and embryogenesis of complex spinal cord lipomas and describes in some detail the technique of total lipoma resection and radical reconstruction of the affected neural placode. Its specific mission is to tackle two main issues surrounding the management of complex dysraphic lipomas: whether total resection confers better long-term benefits than partial resection and whether total resection does better than conservative treatment, i.e. no surgery, for asymptomatic lipomas. Accordingly, the 24-year progression-free survival data of the senior author and colleagues' series of over 300 cases of total resection are compared with historical data from multiple series (including our own) of partial resection, and total resection data specifically for asymptomatic lesions are compared with the two known series of non-surgical treatment of equivalent patients. These comparisons so far amply support the author's recommendation of total resection for most complex lipomas, with or without symptoms. The notable exception is the asymptomatic chaotic lipoma, whose peculiar anatomical relationship with the neural tissue defies even our aggressive surgical approach, and consequently projects worse results (admittedly of small number of cases) than for the other two lipoma subtypes of dorsal and transitional lesions. Prophylactic resection of asymptomatic chaotic lipomas is therefore not currently endorsed. We have also recently found that some dorsal lipomas with clear outline of the conus on preoperative imaging had a significantly better long-term prognosis of preserving neurourological functions without surgery. Whether this subset of lipomas should be managed conservatively until symptoms arise is now an open question awaiting a longer follow-up of a larger cohort of such patients.

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.

Multidisciplinary Management of Children with Occult Spinal Dysraphism: A Comprehensive Journey from Birth to Adulthood

Occult spinal dysraphism (OSD) comprises different forms of failure in embryogenic development that can lead to genitourinary, spinal, or lower limb alterations, thus determining progressive neurological deterioration. The correct management of children harboring OSD represents a significant issue during their life up to adulthood. However, patients often have to entertain individual consultations with each specialist. We settled on a multidisciplinary team comprising pediatric neurosurgeons, urologists, neurologists, orthopedists, and other supporting physicians. We present the results of such actions by analyzing a series of 141 children with OSD subjected to neurosurgical procedures, evaluating the impact of multidisciplinary management on outcomes. We also evaluated the specific actions according to the different ages of OSD patients from birth to adulthood to provide a schematic plan that could represent a basis for establishing and disseminating the need for a multidisciplinary approach in OSD management. The multidisciplinary team allows all consultants to see the patient together, covering specific aspects of history and examination pertinent to their management. Offering a one-stop service prevents coordination issues between the different medical teams, avoids delays or cancellations of the various appointments, optimizes cost-effectiveness, and improves efficiency and parents’ satisfaction.

Split cord malformation concomitant with spinal teratoma without open spinal dysraphism

PURPOSE

Split cord malformation (SCM) presenting concomitant with spinal teratoma without any open spinal dysraphism has rarely been reported in the literature. We aimed to make a systematic review and qualitative analysis of the literature about the topic and present the first case of SCM concomitant with spinal teratoma harboring papillary thyroid carcinoma (PTC) component.

METHODS

Two big search tools (Pubmed/MEDLINE) and Scopus were used. The search strategy was compatible to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). An exemplary case of ours was also presented.

RESULTS

There were 30 patients (15 pediatric and 15 adult). Female and male distribution was even. Median age of the patients was 18 years (range = 0-66 years). The most common presenting symptoms were back pain and lower limb weakness. Spinal teratoma and SCM mostly presented at thoracic/thoracolumbar region in children and lumbar region in adults. Surgical outcome was better in the children compared to the adults.

CONCLUSION

Thoracolumbar region is the most common location for such entity in children, whereas lumbar region for the adults. Surgical resection should be done as much as possible under neuromonitorization. The resected material should be evaluated thoroughly not to miss any malign pathology. Surgical outcome is better when it is done at an early age.

Recurrent tethering in conus lipomas: a late complication not to be ignored

BACKGROUNDS

Recurrent symptomatic tethered cord (RTC) is a long-term complication of spinal cord lipomas, responsible for progressive motor deficits, urologic dysfunction and aggravation of spinal deformities.We retrospectively analysed all cases of recurrent tethering after spinal cord lipoma surgery, the clinical and radiological features that led to the diagnosis, the surgical management and the neuro-orthopedic outcome at the last follow-up.

METHODS

The study was carried out over a period of 20 years on a total of 209 pediatric patients from a single institution, initially treated for a conus lipoma.

RESULTS

9 patients (4,8 %) were surgically treated for a RTC. The age at retethering ranged from 2 to 12 years -median of 7, 4 years. The time before the first and the second surgical procedure, ranged from 19 to 140 months - median of 7 years and a half. The follow-up period after the second surgery ranged from 3 months to 13 years with a median of 50 months. Among symptoms, pain responded very well to surgery. Gait disturbances improved in 50 % after the surgery. One patient with bladder dysfunctions also improved. The rest of the patients maintained the pre-surgical status.

CONCLUSIONS

When RTC is confirmed, child should be referred to surgery as soon as possible, as we showed that the post- operative clinical outcome improved and surgery did not worsen patients. We stressed the fact that the follow-up should be as long as possible for these patients.

Radical resection of lumbosacral lipomas in children: the Great Ormond Street Hospital experience

PURPOSE

In 2009, Pang described a radical resection technique for congenital lumbosacral lipomas, with lower long-term symptomatic re-tethering rates compared with partial resections and conservative management, and low surgical morbidity. We adopted this technique in 2011, and aim to describe our first results.

METHODS

In this monocentric retrospective audit, we included dorsal, transitional, chaotic, and caudal-type lumbosacral lipomas. Exclusion criteria were previously operated lipomas, pure filar lipomas, and concomitant major congenital anatomical urogenital/gastrointestinal abnormalities. Neuro-uro-orthopaedic status at presentation and at three months, one year and last postoperative follow-up, intraoperative electrophysiology, and extent of resection were collected.

RESULTS

From January 2011 to September 2019, 91 patients were operated (median age 2y2m; 63 transitional; 14 caudal; 8 dorsal; 6 chaotic). Preoperatively, 67% were symptomatic. Preoperative and one-year postoperative rates of impaired ambulation (44% to 43%), hypoesthesia (8% to 5%), urodynamic/uroradiological abnormalities (49% to 37%), and foot/ankle deformities (8% to 5%) were comparable, whilst pain improved (25% to 5%) but catheterisation rates increased (21% to 36%). 23/92 (25%) suffered wound-related complications. 2/91 (2%) developed symptomatic re-tethering requiring second surgery. Mean cord/sac ratio was 0.47. 43% had > 20 mm³ residual fat, which improved with increasing surgical experience.

CONCLUSION

Radical lipoma resection, guided by intraoperative neuromonitoring, with reconstruction of the neural placode and expansion duraplasty is technically feasible and results in low rates of late deterioration and re-tethering. Lipoma-type and pre-operative status are important outcome predictors. Operative risks are not insignificant. Future studies need to determine appropriate selection criteria for surgery.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

Purpose

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

Methods

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

Results

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

Conclusions

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

A systematic review and meta-analysis of minimally invasive surgery in children with occult tethered cord syndrome

BACKGROUND

At present, the surgical treatment of occult tethered cord syndrome (OTCS) in children is mostly two types of minimally invasive surgery: filum terminalis laxity or filum terminalectomy. The clinical efficacy and safety of minimally invasive treatment and conservative treatment are still unclear. Therefore, this study will use the advantages of systematic review and meta-analysis to evaluate the objectivity, and explore the effect of minimally invasive surgery on children with occult tethered cord syndrome.

METHODS

A computer search was used to search PubMed, Embase, CNKI, Wanfang Database and other literature search websites about the randomized controlled trials (RCTs) of minimally invasive surgery in children with occult tethered cord syndrome and spinal lipoma. Professional journals were manually searched to avoid omissions. The search keywords were: occult myelolipoma, occult tethered cord syndrome, surgical treatment of tethered cord syndrome, occult tethered cord syndrome.

RESULTS

A total of 6 relevant literatures that could be used for meta-analysis were selected. A total of 425 subjects were included in the article, of which 132 were treated conservatively and 293 were treated surgically. The heterogeneity detection test statistics of the included studies were Chi² (Chi-squared test) =8.18, df (degree of freedom) =5, I²=39%<50%, Z=2.53, and the homogeneity of the included studies was good. The number of unimproved cases under conservative treatment was 40, accounting for 30.30%; the number of unimproved cases under surgical treatment was 33, accounting for 11.26%, and the total unimproved rate of the two groups accounted for 17.17%. The unimproved rate of the experimental group was significantly lower than that of the control group, and the difference was statistically significant (P=0.01). The results of bias analysis showed that there was no significant bias in the literature included in this study.

DISCUSSION

Meta-analysis results confirmed that minimally invasive surgery has a significant effect on the treatment of occult children with tethered cord syndrome. However, due to the small sample size of the included literature, further evaluation of the treatment risk is required.

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.

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.

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.

Dynamic mapping using an electrified ultrasonic aspirator in lipomyelomeningocele and spinal cord detethering surgery-a feasibility study

BACKGROUND

Intraoperative neurophysiologic monitoring (IONM) is an established technique and adjunct of brain and spinal lesion resection surgery. In spina bifida syndrome surgery, mapping of the surgical wound is a common and accepted method in determining the position and functionality of nerve roots of the cauda equina (CE), especially when the anatomy is not straightforward and roots are splayed across or entangled within the lesion. Here, we describe a novel technique of continuous CE mapping using an electrified cavitron ultrasonic aspirator (eCUSA) in children with lipomyelomeningocele (LMMC) lesions.

METHODS

We assessed a method of dynamic CE mapping using an eCUSA as a stimulation probe. Twenty children (0.5-18 years) were included in this study, diagnosed with occult spina bifida LMMC in which the eCUSA stimulator was applied. IONM data and 2-weeks post-operative data were collected.

RESULTS

LMMC lesions were located in the lumbar, sacral, and lumbosacral spine. eCUSA stimulation at 0.3-3.0 mA intensities elicited positive lower extremity muscle responses in 12 of the 20 patients included in the study. These responses allowed the surgeon real-time identification of the nerve roots tangent at the LMMC-cauda equina structure and intensive removal of the fat tissue in the area non-responding to the eCUSA stimulation.

CONCLUSION

Continuous eCUSA-based stimulation of the cauda equina during LMMC resection is a feasible mapping technique with potential added value improving safety of untethering. Future studies evaluating extension of untethering, as well as the rates of retethering and long-term neurological and urological outcomes, are warranted.

Early de-tethering: analysis of urological and clinical consequences in a series of 40 children

PURPOSE

Early de-tethering procedures are performed on spinal dysraphisms to prevent neuro-urological deterioration caused by growth. Partial lipoma removal may cause delayed deterioration by re-tethering, while complete removal may increase the risk of postoperative worsening. The present study evaluates the risk of postoperative deterioration and the protective potential of intraoperative neurophysiological monitoring (IOM), with a special reference to the conus lipomas treated with the radical approach.

METHODS

Forty toddlers (< 24 months) underwent complete perioperative neurological and urological assessment, including urodynamic study (UDS). The dysraphisms were subgrouped according to Pang's classification. IOM was applied in all patients: transcranial motor evoked potentials (tMep) combined with mapping were recorded in all cases while bulbocavernosus reflex (BCR) was evaluable just in 7 cases.

RESULTS

At preoperative evaluation, 11 children already had UDS impairment and 2 had motor disturbances before neurosurgery. At 1-month follow-up, preoperative motor disturbances were stable, 7/11 UDS alterations normalized, and the remaining 4 were stable. At 6-month follow-up, all motor deficits and 8/11 preoperative UDS alterations had improved. Unfortunately, 7 children with previously normal UDS experienced a new impairment after surgery: 2/7 normalized while 5/7 did not recover. This postoperative permanent urodynamic impairment occurred in 4 chaotic lipoma (CLchaos) and in one terminal myelocystocele (TMC) that means a surgical deterioration rate of 22% for the high risk cases.

CONCLUSIONS

This small highly selected series confirms that early de-tethering may stop or revert the spontaneous neuro-urological deterioration: in fact, preoperative UDS impairment was frequent (27.5%) and improved in all the low surgical risk cases (limited dorsal myeloschisis, filar, transitional and dorsal lipomas). On the contrary, in CLchaos and TMC, early de-tethering was unable to revert preoperative UDS impairment, and radical surgery carried a high risk of new neuro-urological deterioration directly caused by the operation. In our experience, IOM had a protective role for motor functions, while it was less effective for the neuro-urological ones, probably due to the anesthesiology regimens applied. In conclusion, among the dysraphisms, CLchoas proved to be the worst enemy that often camouflages at MRI. Affording it without all possible IOM weapons carries a high risk to harm the patient.

Rapid deterioration of an asymptomatic lumbosacral lipoma due to formation of an extracanalicular syrinx: case report

The authors present the case of a 1-month-old girl with a lumbosacral lipoma who then developed an extracanalicular syrinx and experienced rapid deterioration. The patient's initial MRI study, obtained before she became symptomatic, revealed a spinal lipoma with a syrinx in contact with the lipoma-cord interface. She was initially asymptomatic but developed loss of motor function in the left leg 14 days after MRI. Emergency surgery was performed. Intraoperative findings revealed a swollen spinal cord. Lipomatous tissue on the caudal side of the conus was removed subtotally, and the central canal was opened. Expansion of the syrinx was observed intraoperatively. Postoperatively, the patient's left leg paresis remained. Postoperative MRI revealed rostral and extracanalicular expansion of the syrinx. This is the first report on the rapid deterioration of a conus lipoma due to extracanalicular expansion of a syrinx. Careful follow-up and repeat MRI should be considered for patients with spinal lipomas with syringomyelia, especially when the syrinx is attached to the lipoma-cord interface.

Intraoperative Neuromonitoring for Tethered Cord Surgery in Infants: Challenges and Outcome

OBJECTIVE

The aim of this study was to evaluate the efficacy and safety of intraoperative neuromonitoring (IONM) in surgery for tethered cord in infants.

MATERIALS AND METHODS

The study included 87 infants who underwent surgery for closed spinal dysraphism under IONM. Their preoperative neurological and urological statuses were compared with postoperative status clinically. The study design was prospective, and the study's duration was from January 2011 to February 2020. IONM was performed (TcMEP and direct mapping) with an Xltek Protektor 32 IOM system, Natus Neurology/medical Inc., Middleton, USA. Statistical analysis in the form of χ2 is conducted using SPSS.

RESULTS

Overall, among 87 patients, clinical improvement was seen in 28 (28/29) patients with motor deficits, 17 (17/24) with bladder deficits, and 18 (18/24) with bowel deficits. The monitorability for motor and sphincter was 97.3% and 90.7%, respectively. The sensitivity of IONM in predicting new motor deficit was 100%, whereas the specificity was 100%. The negative predictive value of predicting motor deficit was 100%, with a diagnostic accuracy of 100%. There were no complications in this cohort related to the IONM.

CONCLUSIONS

The study has highlighted that the use of IONM is sensitive in identifying motor injury in infants with reliable outcome correlation. Assessment, monitoring, and outcome correlation of bladder and sphincteric functions are a challenge in this cohort.

Neurosurgical management of conus lipoma in Canada: a multi-center survey

OBJECT

Lipomyelomeningocele (LMM) is a congenital spinal cord anomaly. While patients with LMM may initially be asymptomatic, neurological sequelae secondary to LMM may become apparent as the patient ages. Consequently, some pediatric neurosurgeons have advocated for upfront neurosurgical interventions irrespective of the presence of symptoms at diagnosis. By contrast, others pursue a conservative approach when overt neurological symptoms are not yet evident. In light of the various practice styles to the heterogeneous anatomical locations, symptoms, and ages associated with LMM, we have conducted a multi-center survey of Canadian pediatric neurosurgeons using clinical vignettes representative of LMM patients.

METHODS

An online survey of the opinions of Canadian pediatric neurosurgeons was conducted using 5 separate cases with magnetic resonance imaging (MRI) scans of the lumbar spine. Each case was accompanied with the same three clinical vignettes, which varied in severity at time of presentation: asymptomatic, progressive somatic motor deficit, or longstanding overflow incontinence. Participants were asked the question, "Would you offer surgical management?" after each clinical vignette. After the five cases and their corresponding 3 clinical vignettes, participants were asked, "If you answered yes to any of the preceding questions, what type of surgery would you perform?". Options for surgical goals and techniques included complete removal, near-total removal, debulking, detethering, and expansile duroplasty. Surgical adjuncts included CUSA, LASER, and neurophysiologic monitoring.

RESULTS

Twenty-three responses were received from the 38 questionnaires sent out to all staff pediatric neurosurgeons across academic medical centers in Canada. This represented a response rate of 61%. Canadian pediatric neurosurgeons generally maintain a conservative approach to the surgical management of LMM as only 13% (n = 3) of surgeons indicated that they would operate in all scenarios. By contrast, 43% (n = 10) indicated surgical management in only those cases presenting with symptoms, and another 43% (n = 10) displayed a variable surgical approach. Nine percent (n = 2) of participants would not perform surgery for incontinence. The greatest level of disagreement among participants pertained to the management of asymptomatic sacral LMM where 43% of participants favored prophylactic surgery, while 57% of participants preferred conservative management.

CONCLUSIONS

The current study highlights the differences in management of LMM among Canadian pediatric neurosurgeons and provides further support for future prospective cohort studies to develop appropriate expert opinions and guidelines such that the care of LMM patients may be according to evidence-based best practice. This is especially true for the treatment of asymptomatic patients, a patient group that would benefit from a randomized controlled trial to assess the long-term outcomes of conservative and surgical management.

Expression Patterns of Hypoxia-Inducible Factors, Proinflammatory, and Neuroprotective Cytokines in Neuroepithelial Tissues of Lumbar Spinal Lipomas-A Pilot Study

OBJECTIVE

Lumbosacral lipomas (LSLs), one form of closed spinal dysraphism, are congenital disorders of the terminal spinal cord (SC). Delayed neurologic deterioration often occurs in the subsequent developmental course of the patient. Identifying the cellular and molecular factors underlying the progressive damage to neural structures is a prerequisite for developing treatment strategies for LSLs.

METHODS

Nine LSL specimens obtained from the SC/lipoma interface during surgical resection were examined. Normal SC tissue served as a control. Clinical characteristics were obtained, and spinal magnetic resonance imaging was re-evaluated. Cellular marker profiles were established. Immunoreactivity (IR) of hypoxia-inducible factor 1α (HIF-1α/-2α), erythropoietin (Epo)/erythropoietin receptor (EpoR), interleukin-1β (IL-1β)/IL-1R1, and tumor necrosis factor α/tumor necrosis factor receptor type 1 were analyzed qualitatively and semiquantitatively by densitometry. Colabeling with cellular markers was determined by multifluorescence labeling. Cytokines were further analyzed by real-time reverse transcription polymerase chain reaction.

RESULTS

LSL specimens showed significant gliosis. HIF-1α/HIF-2α-IR and Epo/Epo-IR were found at significantly higher levels in the LSL specimens, as were IL-1β-/IL-1β receptor type 1 (IL1-R1) and tumor necrosis factor α/tumor necrosis factor receptor type 1 (P < 0.001), than were the controls. At the messenger RNA level, cytokines appeared partially induced. Double immunofluorescence labeling confirmed the costaining of these factors with inflammatory and glial markers.

CONCLUSIONS

The expression of hypoxia-related and inflammatory mediators was shown for the first time in LSL specimens. These factors might play a role in multifactorial secondary lesion cascades underlying further damage to the neural placode in closed dysraphism.

Surgical Management of Complex Spinal Cord Lipomas : A New Perspective

This review summarises the classification, anatomy and embryogenesis of complex spinal cord lipomas, and describes in some detail the new technique of total lipoma resection and radical reconstruction of the affected neural placode. Its specific mission is to tackle two main issues surrounding the management of complex dysraphic lipomas : whether total resection confers better long term benefits than partial resection, and whether total resection does better than conservative treatment, i.e., no surgery, for asymptomatic lipomas. Accordingly, the 24 years progression-free survival data of the author and colleagues’ series of over 350 cases of total resection are compared with historical data from multiple series (including our own) of partial resection, and total resection data specifically for asymptomatic lesions are compared with the two known series of non-surgical treatment of equivalent patients. These comparisons amply support the author’s recommendation of total resection for most complex lipomas, with or without symptoms. The notable exception is the asymptomatic chaotic lipoma, whose peculiar anatomical relationship with the neural tissue defies even our aggressive surgical approach, and consequently projects worse results (admittedly of small number of cases) than for the other two lipoma subtypes of dorsal and transitional lesions. Prophylactic resection of asymptomatic chaotic lipomas is therefore not currently endorsed.

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.

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.

Surgical management of complex spinal cord lipomas: how, why, and when to operate. A review

This review summarizes the classification, anatomy, and embryogenesis of complex spinal cord lipomas, and it describes in some detail the new technique of total lipoma resection and radical reconstruction of the affected neural placode. Its specific mission is to tackle two main issues surrounding the management of complex dysraphic lipomas: whether total resection confers better long-term benefits than partial resection and whether total resection fares better than conservative treatment-i.e., no surgery-for asymptomatic lipomas. Accordingly, the 24-year progression-free survival data of the author and colleagues' series of over 300 cases of total resection are compared with historical data from multiple series (including the author and colleagues' own) of partial resection, and total resection data specifically for asymptomatic lesions are compared with the two known series of nonsurgical treatment of equivalent numbers of patients. These comparisons amply support the author's recommendation of total resection for most complex lipomas, with or without symptoms. The notable exception is the asymptomatic chaotic lipoma, whose peculiar anatomical relationship with the neural tissue defies even this aggressive surgical approach and consequently projects worse results (admittedly of a small number of cases) than for the other two lipoma subtypes of dorsal and transitional lesions. Prophylactic resection of asymptomatic chaotic lipomas is therefore not currently endorsed.

Diffusion tensor imaging (DTI) and Tractography of the spinal cord in pediatric population with spinal lipomas: preliminary study

PURPOSE

Diffusion tensor imaging (DTI) allows studying the micro and macro architecture. One of the major challenges in dysraphism is to know the morphologic organization of the spinal cord. In a preliminary work, spinal lipoma was chosen for analyzing the micro-architecture parameters and fiber morphology of the spinal cord by DTI with tractography.

METHODS

Twelve patients (0-8 years) related to spinal lipomas treated between May 2017 and March 2018 were included. Tractography reconstruction of the conus medullaris of 12 patients were obtained using the MedINRIA software. The diffusion parameters have been calculated by Osirix DTImap plugin.

RESULTS

We found a significant difference in the FA (p = 0.024) between two age groups (< 24 months old and > 24 months old). However, no significant differences in the mean values of FA, RD, and MD between the level of the lipoma and the level above were noted. The tractography obtained in each case was coherent with morphologic sequences and reproducible. The conus medullaris was deformed and shifted. Destruction or disorganization of fibers and any passing inside the lipomas was not observed.

CONCLUSIONS

Tractography of the conus medullaris in a very young pediatric population (0-8 years old) with a spinal lipoma is possible, reproductive, and allows visualization of the spinal cord within the dysraphism. Analysis of the FA shows that the presence of a lipoma seems to have an effect on the myelination of the conus medullaris. It is during the probable myelination phase that the majority of symptoms appear. Is the myelination per se the cause?

Surgical Outcomes of Pediatric Patients with Asymptomatic Tethered Cord Syndrome

Study Design

A retrospective cohort study.

Purpose

To examine the validity of prophylactic surgery for children with tethered cord syndrome (TCS).

Overview of Literature

Prophylactic surgery for pediatric patients with TCS remains controversial.

Methods

We retrospectively analyzed the surgical outcomes of 14 children (nine boys and five girls) with asymptomatic TCS who were surgically treated at Hokkaido University Hospital between 1989 and 2015.

Results

The median age at the time of initial surgery for asymptomatic TCS was 28.6 months (range, 0–66 months). The median final follow-up period was 142 months (range, 7–232 months). Of the 14 children with asymptomatic TCS, 12 had lumbosacral lipoma and two had meningocele. According to the classification of spinal lipoma, two children had dorsal type, four had caudal type, two had transitional type, and four had filar type. There were no children with lipomyelomeningocele. All children were free of neurological symptoms until 94 months after the initial surgery. Subsequently, one child exhibited delayed neurological deficits and underwent a second surgery because of motor and sensory disturbances; slight sensory disturbance was noted at the final follow-up examination. Another child later showed bowel and bladder dysfunction. However, a second surgery was not performed for this child because his motor and sensory functions were normal; hence, we chose to avoid nerve injury in the case of dissecting adhesion.

Conclusions

All 14 children with asymptomatic TCS were free of neurological symptoms until 94 months after the initial surgery. However, two children exhibited delayed neurological deficits at 94 months and 177 months. We believe that prophylactic surgery for asymptomatic TCS is effective for a certain period. However, because the natural history of TCS is poorly understood, strict follow-up after surgery is necessary.

The pathology of lumbosacral lipomas: macroscopic and microscopic disparity have implications for embryogenesis and mode of clinical deterioration

AIMS

Lumbosacral lipomas (LSL) are congenital disorders of the terminal spinal cord region that have the potential to cause significant spinal cord dysfunction in children. They are of unknown embryogenesis with variable clinical presentation and natural history. It is unclear whether the spinal cord dysfunction reflects a primary developmental dysplasia or whether it occurs secondarily to mechanical traction (spinal cord tethering) with growth. While different anatomical subtypes are recognised and classified according to radiological criteria, these subtypes correlate poorly with clinical prognosis. We have undertaken an analysis of surgical specimens in order to describe the spectrum of histological changes that occur and have correlated the histology with the anatomical type of LSL to determine if there are distinct histological subtypes.

METHODS AND RESULTS

The histopathology was reviewed of 64 patients who had undergone surgical resection of LSL. The presence of additional tissues and cell types were recorded. LSLs were classified from pre-operative magnetic resonance imaging (MRI) scans according to Chapman classification. Ninety-five per cent of the specimens consisted predominantly of mature adipocytes with all containing thickened bands of connective tissue and peripheral nerve fibres, 91% of samples contained ectatic blood vessels with thickened walls, while 22% contained central nervous system (CNS) glial tissue. Additional tissue was identified of both mesodermal and neuroectodermal origin.

CONCLUSIONS

Our analysis highlights the heterogeneity of tissue types within all samples, not reflected in the nomenclature. The diversity of tissue types, consistent across all subtypes, challenges currently held notions regarding the embryogenesis of LSLs and the assumption that clinical deterioration is due simply to tethering.

Prognosis of surgical treatment of the tethered cord syndrome in children

PURPOSE

The aim of this study was to identify the factors relevant to the prognosis of the outcome of the surgical treatment of the tethered cord syndrome (TCS).

METHODS

The results of surgical treatment performed on 58 children with TCS were analyzed, with follow-up periods ranging from 6 months to 5 years. The data of preoperative clinical and instrumental examinations, as well as those of intraoperative electrophysiological diagnostics and morphometry, were compared with the dynamics of the TCS clinical presentation.

RESULTS

The recovery rate was significantly higher in children with filum terminale abnormality (p = 0.014), as well as grade I tethering (p = 0.0037), and when the spinal cord tracts at the level of intervention were intact (p = 0.018). Complete untethering (p = 0.04) and a low threshold value of amperage in direct stimulation (< 1 mA) (p = 0.016) were identified as factors for a favorable outcome. Worsening of neurological symptoms was more frequent in children operated over the age of 10 (p = 0.03), when the TCS was manifested exclusively through the pelvic dysfunction (p = 0.00004), if the F-wave block is less than 30% (p = 0.0045) and the stimulation threshold during root mapping ranged from 1 to 5 mA (p = 0.01).

CONCLUSION

The operation is recommended when structural changes are minimal. In case of severe structural changes, if the spinal cord tracts are intact, the indications for operation are determined by the risk of irreversible structural changes due to the natural course of the disease, although the risks are substantially higher.

Aggressive Resection of Congenital Lumbosacral Lipomas in Adults: Indications, Techniques, and Outcomes in 122 Patients

OBJECTIVE

The authors reviewed the treatment of adult patients with congenital intraspinal lipomas with total/near-total resection and discussed their preoperative characteristics, prognostic factors, and surgical outcomes.

METHODS

Medical records of 122 adult patients with congenital lumbosacral lipomas undergoing total/near-total resection were systematically analyzed. The cohort was subdivided into 3 groups depending on symptom onset age: group 1 (≤5 years, n = 40), group 2 (>5 years but <18 years, n = 33), and group 3 (>18 years, n = 49). Preoperative and postoperative neurologic status were compared between groups and analyzed as a whole.

RESULTS

The most common symptom was bladder dysfunction (82.0%), followed by constipation (76.2%). At the 3-month follow-up, improvement was noted in most patients presenting with pain (87.2%) and neuropathic ulcers (70.0%). Overall, neurologic status was improved in 73.0% of patients and stabilized in 19.7% of patients. A binary logistic regression model identified shorter preoperative duration (P = 0.013) and preoperative pain (P = 0.005) as independent predictors of postoperative improvement. Neurosurgical complications developed in 16 patients, and wound complications occurred in 2 patients. Two of 3 patients who had recurred symptoms underwent repeated detethering surgery during long-term follow-up.

CONCLUSIONS

Despite longer preoperative duration than the pediatric population, adult patients with lumbosacral lipomas can still benefit from total/near-total resection especially regarding pain and foot ulcers, with low surgery-related morbidity. The long-term advantage of resecting additional lipoma in adults remains a point of discussion.

Placode rotation in transitional lumbosacral lipomas: are there implications for origin and mechanism of deterioration?

PURPOSE

Rotation of the lipoma-neural placode has been noted in transitional lumbosacral lipomas. The purpose of this study was to confirm this rotation; that this rotation occurs with a preference to the left, and correlates with clinical symptoms. In addition, this study tests the hypothesis that this rotation occurs through local mechanical forces rather than intrinsic congenital malformation.

METHODS

Lipomas were classified as per the Chapman classification. Degree of rotation of the placode from the coronal plane was recorded along with the presence of herniation outside of the vertebral canal. Abnormalities on urodynamic testing were recorded, along with neuro-orthopaedic signs picked up on formal neuro-physiotherapy assessment.

RESULTS

Placode rotation occurs more frequently in the transitional group. Regardless of lipoma classification, rotation was much more common to the left. Furthermore, when lateralisation of symptoms was present, this strongly correlated with the direct of rotation. There was no difference in rotation of the placode whether it was within (lipomyelocoele) or without the vertebral canal (lipomyelomeningocoele).

CONCLUSIONS

Placode rotation is a feature of transitional lumbosacral lipomas and may account for the increase in symptoms amongst this subgroup. Herniation of the placode outside the vertebral canal does not increase the risk of rotation suggesting a congenital cause for this finding rather than a purely mechanical explanation.

Evaluation and management of tethered cord syndrome in occult spinal dysraphism: Recommendations from the international children's continence society

AIMS

As awareness and frequency of tethered spinal cord (TSC) related to occult spinal dysraphism (OSD) has increased with magnetic resonance imaging (MRI), variability exists in its evaluation and management. Due to no published level I data, we summarize the current International Children's Continence Society (ICCS) recommendations for diagnosis and treatment of OSD.

METHODS

Guidelines were formulated based on analysis of pertinent literature and consensus among authors. This document was vetted by the multidisciplinary members of the ICCS via its website before submission for peer review publication.

RESULTS

The more frequent diagnosis of OSD is associated with increased operative intervention. Spinal cord untethering (SCU) has a highly variable risk profile, largely dependent on the specific form of OSD. Progressive neurological deterioration attributed to "tethered cord" may occur, with or without surgery, in selected forms of OSD whereas other cohorts do well.

CONCLUSION

Infants with classic cutaneous markers of OSD, with progressive neurologic, skeletal, and/or urologic findings, present no diagnostic or therapeutic dilemma: they routinely undergo MRI and SCU. Conversely, in asymptomatic patients or those with fixed, minor abnormalities, the risk profile of these OSD cohorts should be carefully considered before SCU is performed. Irrespective of whether or not SCU is performed, patients at risk for progression should be followed carefully throughout childhood and adolescence by a multidisciplinary team.

Lipomyelomeningocele for the urologist: Should we view it the same as myelomeningocele?

INTRODUCTION

The primary urologic objectives for lipomyelomeningocele (LMM) and myelomeningocele (MM) are preserving renal integrity and achieving continence. Due to this common ground, LMM and MM are urologically treated the same. However, unlike MM, LMM may present with no evident functional concerns. Indications for and timing of tethered cord release (TCR) in LMM are therefore controversial. Long-term urologic outcomes are not well defined.

OBJECTIVE

Expectations for continence and potential for intermittent catheterization (CIC) following TCR in LMM are important for realistically counseling families regarding future needs. The present study aimed to identify prognostic factors for continence and need for CIC in LMM.

STUDY DESIGN

The present study retrospectively identified 143 patients from the multidisciplinary clinic who underwent TCR for LMM between 1995 and 2010. Concomitant anorectal/genitourinary anomalies, filar lipoma, fatty filum, previous TCR, and follow-up <1 year were excluded. Analysis was limited to those toilet trained or aged ≥6 years at latest follow-up. Lipomyelomeningocele was classified as dorsal, distal, transitional or chaotic. Pre- and post-TCR urologic status was assessed. Ability to achieve urinary continence, with or without CIC, was the primary outcome, and need for CIC was the secondary outcome of interest.

RESULTS

A total of 56 patients met inclusion criteria. Median age at TCR was 4.4 months (range 1.0-224.0) with a median follow-up of 10.7 years (range 1.3-19.1); 68% were asymptomatic at presentation. Clinical symptoms were urologic in 7%. At the latest follow-up, 86% of patients were continent spontaneously or with CIC (Summary Fig.). Of the four patients who presented with urologic symptoms, all were continent, but three required CIC. Overall, 23% of patients required CIC. Median age at CIC initiation was 7.6 years (range 1.6-17.4). Long-term continence was not associated with any demographic, anatomic, surgical or functional variable. Need for CIC at latest follow-up was associated with symptomatic presentation, partial TCR, transitional lipoma, and high-risk pre-operative urodynamics.

DISCUSSION

In this series of primary TCR for LMM, where 93% of patients were urologically asymptomatic before TCR, prospects for continence were excellent. No studied parameter clearly impacted continence; however, need for CIC was associated with multiple variables.

CONCLUSIONS

Clear predictors for continence after TCR will require additional long-term patient outcomes. Families can anticipate 23% likelihood of CIC, which is considerably less than in MM, but long-term urologic follow-up is still strongly recommended.

Spinal column shortening for tethered cord syndrome associated with myelomeningocele, lumbosacral lipoma, and lipomyelomeningocele in children and young adults

OBJECTIVE Tethered cord syndrome is the clinical manifestation of an abnormal stretch on the spinal cord, presumably causing mechanical injury, a compromised blood supply, and altered spinal cord metabolism. Tethered cord release is the standard treatment for tethered cord syndrome. However, direct untethering of the spinal cord carries potential risks, such as new neurological deficits from spinal cord injury, a CSF leak from opening the dura, and retethering of the spinal cord from normal scar formation after surgery. To avoid these risks, the authors applied spinal column shortening to children and transitional adults with primary and secondary tethered cord syndrome and report treatment outcomes. The authors' aim with this study was to determine the safety and efficacy of spinal column shortening for tethered cord syndrome by analyzing their experience with this surgical technique. METHODS The authors retrospectively reviewed the demographic and procedural data of children and young adults who had undergone spinal column shortening for primary or secondary tethered cord syndrome. RESULTS Seven patients with tethered cord syndrome caused by myelomeningocele, lipomyelomeningocele, and transitional spinal lipoma were treated with spinal column shortening. One patient with less than 24 months of follow-up was excluded from further analysis. There were 3 males and 4 females; the average age at the time was surgery was 16 years (range 8-30 years). Clinical presentations for our patients included pain (in 5 patients), weakness (in 4 patients), and bowel/bladder dysfunction (in 4 patients). Spinal column osteotomy was most commonly performed at the L-1 level, with fusion between T-12 and L-2 using a pedicle screw-rod construct. Pedicle subtraction osteotomy was performed in 6 patients, and vertebral column resection was performed in 1 patient. The average follow-up period was 31 months (range 26-37 months). Computed tomography-based radiographic outcomes showed solid fusion and no instrumentation failure in all cases by the most recent follow-up. Five of 7 patients (71%) reported improvement in preoperative symptoms during the follow-up period. The mean differences in initial and most recent Scoliosis Research Society Outcomes Questionnaire and Oswestry Disability Index scores were 0.26 and -13%, respectively; minimum clinically important difference in SRS-22 and ODI were assumed to be 0.4% and -12.8%, respectively. CONCLUSIONS Spinal column shortening seems to represent a safe and efficacious alternative to traditional untethering of the spinal cord for tethered cord syndrome.