Factors in neurological deterioration and role of surgical treatment in lumbosacral spinal lipoma

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.

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

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

Spinal lipoma of the filum terminale: review of 174 consecutive patients

PURPOSE

Spinal lipoma of the filum terminale (LFT) is a congenital lumbosacral anomaly that can cause tethered cord syndrome. Purposes of this study are to clarify preoperative characteristics of LFT, to elucidate surgical effects, and to discuss the rationale of prophylactic surgery for LFT.

METHODS

Medical data of 174 children (2008-2014) who underwent section of LFT were prospectively recorded for prevalence of symptoms, skin stigmas, and associated malformations, motivator of diagnosis, conus level, and surgical outcome. Mean age at surgery was 4.1 ± 4.2 years (37 days to 17.7 years).

RESULTS

Ninety-four children (54.0 %) had skin stigmas and 60 (34.5 %) had certain perineal malformations. Seventy-nine children (45.4 %) were symptomatic. The most common motivator for diagnosis was skin stigmas (44.3 %), followed by associated malformations (33.3 %), and symptoms (20.1 %). The age at surgery was significantly older in symptomatic patients than in asymptomatic patients (p < 0.001). Surgery improved symptoms in 50 % of patients at 2.1-year follow-up period. Of 85 asymptomatic patients, all except one remained asymptomatic postoperatively and none of the symptomatic patients deteriorated. The presence of associated malformations and the conus level did not affect surgical outcome. Postoperative complications developed in nine patients (5.2 %): seven transient local problems, one definitive urological deterioration, and one transient respiratory problem.

CONCLUSIONS

Surgery for LFT was a simple and safe procedure. It improved half of symptomatic patients and stopped the deterioration of the others. Even if only one of the asymptomatic patients deteriorated at maximum follow-up, the role of prophylactic surgery remains a point of discussion.

Tethered cord syndrome in adults

OBJECT

The treatment of tethered cord syndromes in adults is discussed regarding the natural history and surgical indications. The author analyzes data obtained in patients who were diagnosed with a tethered cord in adulthood and either underwent surgical or conservative therapy between 1991 and 2009.

METHODS

Since 1991, data obtained in 2515 patients with spinal cord pathologies were entered into the spinal cord database, and prospective follow-up was performed through outpatient visits and questionnaires. Of the 2515 patients, 85 adults with a tethered cord syndrome formed the basis of this study. The tethering effect was caused either by a split cord malformation, a thick filum terminale, a conus medullaris lipoma with extradural extension, or various combinations of these mechanisms. The mean age of the patients was 46 ± 13 years (range 23-74 years) and the mean follow-up duration was 61 ± 62 months. Two groups were distinguished based on the absence (Group A, 43 patients) or presence (Group B, 42 patients) of an associated lipoma or dysraphic cyst (that is, dermoid, epidermoid, or neurenteric cyst). Surgery was recommended for patients with symptoms only. Short-term results were determined within 3 months of surgery, whereas long-term outcomes (clinical recurrences) were evaluated using Kaplan-Meier statistics.

RESULTS

For all patients, pain was the most common major complaint. Severe neurological deficits were rare. In Group A, 20 of 43 patients underwent surgery, whereas in Group B 23 of 42 patients underwent surgery. Among individuals who did not undergo surgery, 17 patients refused surgery and 25 patients underwent recommended conservative treatment. Short-term postoperative results indicated a significant improvement of pain and a stabilization of neurological symptoms. Long-term results showed a good prognosis in patients in whom first-time (that is, nonrevision) surgery achieved successful untethering, with a 10-year rate of neurological stabilization in 89% of Group A and a 10-year rate of neurological stabilization in 81% of Group B patients. The benefit of secondary operations in Group B was limited, with eventual clinical deterioration occurring in all patients within 10 years. For patients treated conservatively, follow-up information could be obtained in 33 of 42 patients. Twenty-eight patients remained in stable clinical condition. Only 5 of the conservatively treated patients experienced clinical deterioration over time; in 4 of these individuals with deterioration, surgery had been recommended but was refused by the patient. The clinical recurrence rate in all conservatively treated patients was 21% after 10 years. With a recommendation for surgery this figure rose to 47% within 5 years.

CONCLUSIONS

Surgery in adult patients with a tethered cord syndrome should be reserved for those with symptoms. In surgically treated patients, pain relief can often be achieved, and long-term neurological stabilization tends to persist more often than it does in conservatively treated patients. A conservative approach is warranted, however, in adult patients without neurological deficits. Revision surgery in patients with complex dysraphic lesions should be performed in exceptional cases only.

Embryopathogenetic surgicoanatomical classification of dysraphism and surgical outcome of spinal lipoma: a nationwide multicenter cooperative study in Japan

OBJECT

The natural history of asymptomatic spinal lipoma in infancy remains unclear, and the indication for the prophylactic untethering operation is still debatable. To address this question, a multicenter cooperative study for the treatment of spinal lipoma was performed by the 7 most active institutions in neurosurgical care for spina bifida in Japan between 2001 and 2005.

METHODS

Patients were classified using the embryopathogenetic surgicoanatomical classification. Their neurosurgical postoperative course was analyzed using the Spina Bifida Neurological Scale. Among 261 patients, 159 were asymptomatic and 102 were symptomatic.

RESULTS

Of the 136 patients for whom prophylactic surgeries were performed, 135 remained asymptomatic and only 1 (0.4%) of the 261 patients presented with mild sensory disturbance. Mild foot deformity was identified in 1 (4.3%) of 23 conservatively observed patients. Of 100 symptomatic patients, deterioration after surgery was seen in 6%, and improvement in 44%. Complete resolution of symptoms was seen in only 14.2%. Filar types for patients > 3 years old improved in Spina Bifida Neurological Scale scores from 12.3 to 14.0. The mean age of symptomatic patients with lipomyelomeningocele was the youngest of all (1.3 years), which indicates lipomyelomeningocele may deteriorate in early infancy. Improvements from surgery were seen for all types of lipoma except the caudal type, presenting at an older mean age (15 years).

CONCLUSIONS

A low rate of postsurgical worsening indicates that surgeries for asymptomatic and symptomatic lipomas are safe. Surgeries done after the onset of symptoms seldom cure the patients. These two results support early untethering for any kind of lipoma; however, further study of the natural history is required.

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.

Urodynamic Evaluation in Children With Lipomeningocele: Timing for Neurosurgery, Spinal Cord Tethering and Followup

PURPOSE

We assessed the usefulness of urodynamic testing for determining the optimal timing of surgery and for evaluating the development of bladder function in children with lipomeningocele.

MATERIALS AND METHODS

We retrospectively evaluated 64 patients (40 females) 3 to 17 years old (mean 8.5) with lipomeningocele. Patients were divided into 3 groups based on age at surgery, ie younger than 12 months (34 patients), 12 to 36 months (17) and older than 36 months (13). All patients underwent urodynamic testing preoperatively and during extended followup (mean 6.5 years, range 3 to 12).

RESULTS

Bladder capacity and mean detrusor leak pressure improved in all groups but particularly in patients operated on within the first year of life. At the end of the study mean bladder capacity was 420 cc in patients younger than 12 months, 300 cc in those 12 to 36 months old and 260 cc in those older than 36 months (p <0.01), and mean detrusor leak pressure was 37, 54 and 55 cm H(2)O, respectively (p <0.01). At the latest followup 65% of patients in the youngest group had improved urodynamic parameters vs 33% of those 12 to 36 months old and 28% of those older than 36 months.

CONCLUSIONS

Urodynamic evaluation and the presence of neurological impairment have crucial roles in determining the optimal timing of surgery in patients with lipomeningocele, and in diagnosing the onset of tethered cord. Our data show that early surgical repair seems to reduce the risk of neurological deterioration of the lower urinary tract, and allows a more physiological development of urinary function.

Dynamic morphological changes in lumbosacral lipoma during the first months of life revealed by constructive interference in steady-state (CISS) MR imaging

OBJECTS AND METHODS

In this study, we demonstrate the morphological change in two cases of lumbosacral lipoma during the first few months of life using a three-dimensional Fourier transformation-constructive interference in a steady-state (CISS) sequence that enables high-resolution images to be obtained with excellent contrast between cerebrospinal fluid (CSF), spinal roots, and lipoma.

RESULTS

The CISS images clearly demonstrated the dynamic morphological changes such as lipoma growth observed in both cases and increased tethering effect in the case with lipomyelomeningocele.

CONCLUSION

We have to keep in mind the potential for these morphological changes of the spinal lipoma during the first few months of life.

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.

Spinal lipomas

Lipomas of the spinal cord are among the most fascinating lesions encountered by the pediatric neurosurgeon. An understanding of spinal lipomas may, however, be difficult because the terminology used to describe the accumulations of spinal fat is confusing, inconsistently applied, and at times contradictory. An anatomical characterization of lipomas may assist in understanding these lesions. Lipomas of the spinal cord are very rare and cause symptoms related to mass effect and secondary compressive myelopathy. Lipomas of the conus medullaris (or lipomyelomeningocele) are the most common form of fatty masses in the spine and can be divided into dorsal, caudal, and transitional forms. These lesions are a manifestation of occult spinal dysraphism and a common cause of the tethered cord syndrome (TCS). The natural history of untreated lipomyelomeningocele, although incompletely understood, appears to be progressive neurological deterioration with loss of bladder control. Timely, careful surgical intervention may prevent significant neurological deterioration and progressive disability in the majority of children harboring these lesions. In surgical intervention the surgeon seeks to disrupt the connection between the fibrofatty mass and underlying cord as well as to reestablish normal anatomical planes. Several intraoperative video segments illustrating lipomyelomeningocele resection are included in this paper. Lipomas of the terminal filum (fatty filum) are truly occult and are also associated with TCS. Surgical treatment of filum lipomas carries significantly lower risk than that for lipomas of the conus medullaris. Again, the goal of surgery is to disrupt the connection between the abnormal fibrofatty tissue and the underlying spinal cord.