Leptomyelolipoma: analysis of 20 cases

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.

Lack of uniformity in the clinical assessment of children with lipomyelomeningocele: a review of the literature and recommendations for the future

OBJECTIVE

An objective clinical assessment tool whose accuracy and reproducibility can be validated is essential for the initial evaluation, selection for surgery and surveillance of children with lipomyelomeningocele (LMMC). The aim of this study was to analyse the large number of such tools presently in use and recommend an alternative that could lead to greater uniformity between different series and greater consistency in the assessment of individual patients.

METHODS

A systematic review of the literature between January 1980 and December 2010 was undertaken and details of how the children in each series were assessed and the degree to which age was taken into account recorded.

RESULTS

Thirty-six different assessment tools were used in 40 different publications. None was validated in all aspects. Objective measures were used most in urological assessments but rarely in other domains. Age-specific assessments were used in only 10 % of publications.

CONCLUSION

This study confirmed that the assessment tools for evaluation of children with LMMC are inconsistent, often vague and poorly validated. This compromises the ability of clinicians who care for them to compare studies across centres for both treated and untreated children. We have sought to highlight those criteria which are relevant, measurable and reproducible and which might be combined into an easily applied assessment.

Lateral tethering intraspinal lipoma with scoliosis

The authors present an unusual case of an intradural lipoma at the thoracolumbar level causing lateral tethering of the spine, with complicated scoliosis. A 6-year-old girl was admitted with progressive change in posture detected by her parents. Thoracolumbar scoliosis was detected by physical examination and X-ray studies. Spinal magnetic resonance imaging revealed an intradural lipoma and right lateral tethering of the spine at the upper lumbar level. After surgical release of lateral tethering and resection of the lipoma, fusion was performed by the orthopedic surgery team. Radiological and intraoperative findings of this extremely rare case are discussed.

Congenital spinal lipomatous malformations: part I--Classification

BACKGROUND

Congenital spinal lipomatous malformations constitute a diverse group of lesions. There is considerable confusion in the literature regarding their terminology and a proper classification is long overdue. The first part of this two part report sets out a proposed classification scheme.

METHODS

On the basis of this author's experience with 80 patients with a congenital spinal lipomatous malformation treated over a 10 year period, a new classification is proposed. The proposed classification divides congenital spinal lipomatous malformations into two broad groups: 1. Lipomas without dural defect and, 2. Lipomas with dural defect. Within each group, there are several subtypes. These two broad groups differ from one another in their embryology, clinical presentation, operative findings, complications and prognosis

FINDINGS

Group I consists of Lipomas without dural defect. Included in this group are: Filum lipoma, caudal lipoma without dural defect, and intramedullary lipoma. Group II consists of lipomas with dural defect. Included in this group are: dorsal lipoma, caudal lipoma with dural defect, transitional lipoma, lipomyelocele, and lipomyelomeningocele. The definitions of the various subtypes and radiological and operative findings of all these lesions are described.

CONCLUSIONS

Congenital spinal lipomatous malformations constitute a wide spectrum of lesions ranging from relatively simple lipomas of the filum terminale to complex malformations. These lesions differ from one another in their embryology, clinical presentation, operative strategies, complications and prognosis. Failure to differentiate between the different forms of congenital spinal lipomatous malformations may lead to inaccurate assumptions regarding prognosis and inappropriate management. The proposed classification seeks to address these issues.

RADIOLOGICAL FINDINGS AND CLINICAL COURSE OF CONUS LIPOMA

OBJECTIVE

A significant variety in morphology of conus lipomas may underlie differences in clinical presentation of the patients and controversy in surgical management. We retrospectively studied 58 patients with conus lipomas at our institutions. The purpose of this study was to infer the clinical course from the radiological findings and to provide information for decision-making in planning for surgical treatment.

METHODS

The patients underwent untethering surgery between 1984 and 2005. There were 35 transitional and 23 dorsal lipomas. The age at surgery ranged from 1 month to 50 years (median, 4 yr). Preoperative clinical history, radiological findings, and postoperative results were analyzed.

RESULTS

Fifteen patients were asymptomatic, and 43 patients were symptomatic preoperatively. Twenty-one patients presented with motor deficits of the lower extremities. In seven patients, motor deficits appeared early, before 1 year of age. Massive lipomas compressing the cord or herniation of the spinal cord into the subcutaneous tissue were characteristic findings of such early deterioration. Motor deficits were present in 73% of patients with lipomas extending to the lumbar level, whereas 88% of patients with lipomas confined to the sacral level had only urinary deficits. During a mean postoperative follow-up period of 7.9 years, 4 (27%) of the 15 asymptomatic patients developed urinary and/or motor deficits, and 12 (28%) of the 43 symptomatic patients showed further neurological deterioration.

CONCLUSION

This study demonstrates that the location and morphology of conus lipomas influence the neurological presentation of the patients. Early prophylactic surgery is a reasonable treatment option if early deterioration is predicted by imaging studies.

Outcome of untethering for symptomatic spina bifida occulta with lumbosacral spinal cord tethering in 31 patients: analysis of preoperative prognostic factors

BACKGROUND CONTEXT

The most important goal for treating symptomatic lumbosacral spinal cord tethering is early untethering.

PURPOSE

To investigate preoperative symptoms that may have affected the outcome.

STUDY DESIGN

Patients with or without improvement and with or without favorable outcome after untethering were compared retrospectively by chart and image review.

PATIENT SAMPLE

Thirty-one patients (age between 2 days to 25 years) with spina bifida occulta and symptomatic cord tethering were analyzed. Presenting symptoms (neurological deficits, urological dysfunction, and lower limb deformities) were assessed before and after untethering.

OUTCOME MEASURES

Favorable outcome was defined as complete relief of symptoms or mild symptoms whereby patients are able to look after their own personal care without assistance. Unfavorable outcome was defined as moderate or severe disability whereby patients are unable to attend to their own bodily needs without assistance, are bedridden, or require constant nursing attention.

METHODS

Differences in patient characteristics and presenting symptoms were compared between those with and without clinical improvement and favorable outcome. Multivariate logistic regression was used to identify prognostic factors affecting the outcome.

RESULTS

The average age at surgery was 7.2 years, with a male-to-female ratio of 1.2. The average follow-up time was 4 years. At least one of the following symptoms was present in all patients: neurological deficits (83.9%), urological dysfunction (77.4%), or limb deformities (38.7%). After untethering, all patients had either symptoms stabilized (14 patients, 45.2%) or improved (17 patients, 54.8%), and 14 patients (45.2%) achieved total resolving of symptoms. Logistic regression confirmed that younger age (< or =2 years, odds ratio [OR] 22.0, p=.026), lipomas of filum terminale (OR 25.6, p=.042), and a poor anal tone (OR 10.4, p=.061) were positive prognostic factors for the improvement in symptoms. The functional outcome was determined by the age at surgery (OR 0.9 per year since 1 year old, p=.04) and the presence of limb deformities (OR 0.06, p=.017).

CONCLUSIONS

In conclusion, our study suggests that untethering should be performed immediately once the patient shows evidence of symptomatic lumbosacral cord tethering, irrespective of age. Untethering can interrupt progression of symptoms, but sphincter dysfunction and muscle weakness are more likely to improve or resolve. Benefits can be seen in all patients, but young children (before 2 years old) have a higher chance to gain favorable outcome. Retethering is a main concern during follow-up, particularly for the more complicated lipomyelomeningoceles. Investigations using electrophysiologic and urodynamic studies are helpful for early detection of subtle symptomatic cord tethering or retethering.

TRANSIENT SYRINGOMYELIA LEADING TO ACUTE NEUROLOGICAL DETERIORATION AFTER REPAIR OF A LIPOMYELOMENINGOCELE

OBJECTIVE

Transient paraplegia in the immediate postoperative period after lipomyelomeningocele repair is uncommon and is not discussed in the literature. We present the unique case of a patient who developed transient paraplegia 48 hours after lipomyelomeningocele repair attributable to the acute development of a thoracic syrinx.

CLINICAL PRESENTATIOn

At birth, the patient was noted to have a large skin-covered mass in the lumbosacral region. On neurological examination, both iliopsoas and quadriceps exhibited 3/5 motor function, and the plantar flexors and dorsiflexors exhibited 1/5 motor function. Urodynamic studies were normal. Magnetic resonance imaging demonstrated the presence of a lipomyelomeningocele associated with tethering of the spinal cord in the lumbosacral region.

INTERVENTION

At 5 months of age, the patient underwent repair of the lipomyelomeningocele. After surgery, the patient developed progressive paraplegia along with bowel and bladder dysfunction. Given the concern about a postoperative hematoma resulting in cauda equina syndrome, the patient returned to the operating room for a wound exploration. No compressive lesion such as a hematoma was found at surgery. A postoperative magnetic resonance imaging scan obtained afterward, however, demonstrated the presence of a large thoracic syrinx.

CONCLUSION

Syrinx formation can occur as early as 48 hours after lipomyelomeningocele repair, leading to progressive lower extremity weakness and bowel and bladder incontinence. In the immediate postoperative period, an acute syrinx can mimic cauda equina syndrome, and a magnetic resonance imaging scan is necessary to distinguish between these two entities. In this patient, the syrinx was transient and resolved without a shunting procedure.

Critical analysis of the Chiari malformation Type I found in children with lipomyelomeningocele

OBJECT

Occasional comments are found in the literature regarding patients with lipomyelomeningocele and concomitant Chiari malformation Type I (CM-I). The object of this study was to explore the association between these two conditions.

METHODS

The authors performed a retrospective database analysis of lipomyelomeningocele cases to identify cases of concomitant CM-I. Analysis of posterior fossa volume (based on the Cavalieri principle) was performed in all identified cases in which appropriate neuroimages were available, and the results were compared with those obtained in age-matched controls. Seven (13%) of 54 patients with lipomyelomeningocele were found to also have CM-I. Two of these were symptomatic (cervicothoracic syrinx and occipital headaches) and required posterior fossa decompression. No correlation was found between the amount of hindbrain herniation and the level of the conus medullaris or the type of lipomyelome-ningocele (for example, caudal or transitional). Volumetric studies of the posterior fossa revealed normal age-matched volumes in all but one patient (who had asymptomatic CM-I).

CONCLUSIONS

The incidence of CM-I in patients with lipomyelomeningocele appears to be significantly greater than that of the general population and the association rate is too high for the finding to be a chance occurrence. Decreases in the volume of the posterior cranial fossa were not found in the majority of patients in this small cohort; therefore, the cause of the concomitant occurrence of lipomyelomeningocele and CM-I remains undetermined. Clinicians should consider obtaining imaging studies of the entire neuraxis in patients with lipomyelomeningoceles and should investigate other causes for syringes found in association with lipomyelomeningoceles.

Prognostic factors affecting urologic outcome after untethering surgery for lumbosacral lipoma

OBJECTS

The authors report results of preoperative and postoperative urodynamic studies (UDS) and prognostic factors of urologic outcome in cases of lumbosacral lipomas for which prolonged follow-up data were available.

MATERIALS AND METHODS

The present series includes 42 consecutive cases of lumbosacral lipoma in patients aged 2 months to 15 years who underwent untethering operation during the period from 1986 to 1997. All of them underwent preoperative and postoperative UDS. At the last follow-up (mean duration of follow-up 108 months, range 44 to 176 months), 26 cases maintained social continence with or without intermittent catheterization. Young age (< or =12 months) at operation, preoperative absence of urologic symptoms, and absence of neurologic abnormalities were significantly correlated with favorable urologic outcome.

CONCLUSION

UDS in cases with lumbosacral lipomas is a valuable tool for detecting neurourologic abnormalities as well as for monitoring the postoperative course and guiding management. History taking and neurologic examination are also proved to be important aspects in the evaluation of children with lumbosacral lipomas, predictive of urologic outcome. Better urologic results are anticipated if surgery is performed when the child is 12 months old or younger.

The role of intraoperative electromyographic monitoring in lumbosacral lipomas

OBJECTIVE

To demonstrate the role of intraoperative multichannel electromyographic (EMG) monitoring to reduce postoperative deterioration and achieve full untethering of complex occult dysraphisms.

METHODS

A retrospective analysis was performed on 66 patients who underwent operation for lumbosacral lipomas. Twenty recent cases were submitted to EMG monitoring and stimulation.

RESULTS

All patients presented symptoms at the time of surgery, and 74% exhibited progressive deterioration during the lengthy preoperative period. Postoperative surgery-related deterioration was observed in 6% of patients. This number was reduced to zero with the introduction of intraoperative EMG monitoring.

CONCLUSION

Intraoperative multichannel EMG monitoring can be carried out and requires only minimal changes to anesthetic procedures. With this method, it is possible to better identify the neural structures of complex malformations, reducing the risks of surgical damage and incomplete detethering.

[Intradural cervical lipoma without neurologic involvement; report of a case]

Lipomas are masses composed of mature adipose tissue, usually affecting lumbosacral levels, often associated with neural tube defects. Spinal lipomas at more rostral levels are usually unassociated with congenital abnormalities, but may produce a more severe neural compromise. Rare reports of cervical lipoma without neurological deficit have been described. We present the case of a 10-years-old girl who complained of cervical pain and stiff neck related to a C7-T1 intradural lipoma, without neurological affectation. The lipoma was partially resected without postoperative deterioration.

Spinal lipomatous malformations

Spinal lipomatous malformations (SLM) include all the closed neural tube defects (NTD) with excessive lipomatous tissue in the spinal cord or filum terminale. We evaluated 65 cases of SLM seen & operated at our department in the last 7 years. Of these only 9 were asymptomatic and 8 were below 2 years of age. There were more males than females. In addition to subcutaneous lipoma many patients also had hypertrichiosis and dermal sinus as cutaneous makes. Twenty patients had foot deformity and 5 had unilateral limb shortening. Sixty-two patients had MRI and 3 had CT myelogram for evaluation. These revealed 7 patients with Chiari malformations, 10 with focal syrinx and 2 patients underwent VP shunt for hydrocephalus. Sacral agenesis was seen in 5 patients. Clinical features were similar to other cases of spinal dysraphism except that sensory loss and trophic ulcer were more frequent. Intradural lipoma and tethering was seen in 18 cases whereas intramedullary lipoma & conus lipoma was seen in 40 & 7 cases respectively. Additional tethering lesion was seen in 1/3 cases and was treated simultaneously. Preoperative deficits improved in 28 cases and stabilized in 33 cases. Three patients developed fresh deficits after surgery. We observed 8 CSF leaks and 4 wound infections in postoperative period. It is very clear from our data that a patient has about 95% chances that his neurological status may improve or stabilize following surgery and the risk of developing fresh deficits is about 5%. We, therefore, suggest that all patients of SLM should be treated with aggressive surgical management for best results.

Neurological and medico-social problems of spina bifida patients in adolescence and adulthood

Chronological changes in the neurological manifestations of spina bifida are well recognized in the early developmental periods: fetal, neonatal, infantile, pre-school and school life. However, little has been written about the medical and medico-social problems of spina bifida patients in adulthood. Patients now in this age group had the condition diagnosed and managed in an era when modern neurosurgical concepts were only just beginning to be established with the aid of invasive methodology. In our series of 141 cases of spina bifida, 18 patients (13.5%) were over 16 years of age. These included 9 cases each of spina bifida aperta (myeloschisis) and spina bifida occulta (spinal lipoma). The ages ranged from 16 to 47 years (mean: 23.5 years) in the former and from 16 to 57 years (mean: 29.2 years) in the latter group. During the long-term follow-up with quantitative analysis of the spinal neurological changes using the spina bifida neurological scale (SBNS), the final outcomes appeared very grave. Except for 1 case in each group-1 grade III in the spina bifida aperta group and 1 grade II in the spina bifida occulta group-all patients over the age of 27 years were classed as having grade IV disease. There were 2 patients with spina bifida aperta in whom postoperative paraplegia appeared after delayed radical repair (at the ages of 3 years and 18 years) and 3 patients with spina bifida occulta in whom obvious neurological deterioration was observed as the natural history with ongoing paraparesis at the spinal level or late onset of sexual problems. The other group included 2 patients with spinal lipoma in whom late neurological deterioration was observed and who were obliged to undergo a second operation in spite of aggressive early procedures performed during infancy. Among the patients with spina bifida aperta, 2 had marked ventriculomegaly as a form of long-standing overt ventriculomegaly in the adult (LOVA). After the CSF shunt procedure both these patients had problems with delicate shunt dependence and requested fine shunt flow regulation. Two patients in this group also suffered from severe depression. This study involves a limited number of patients, but it may be useful for reference on various points: (1) future prospects for the management of pediatric cases of spina bifida as practiced in the majority of hospitals; (2) natural histories of untreated cases and surgical indications for preventive procedure in spinal lipoma in early infancy; and (3) internationally differing levels of management of spina bifida and the historical development of individual countries' approaches to the problems.

Presacral myelolipoma: sonographic appearance

We describe an uncommon case of presacral myelolipoma in a 11/2-year-old boy, causing urinary retention and constipation. The sonographic appearance of the mass mimics a "pseudoprostatic enlargement".