Clinical characteristics and surgical outcome in 25 cases of childhood tight filum syndrome

Comparison of the inter-laminar approach and laminotomy open approach for filum terminale lipoma: A retrospective analysis

PURPOSE

Filum terminale lipoma (FTL) causes spinal-cord tethering and is associated with tethered-cord syndrome, which is treated by dissection of the entrapment. The conventional treatment for FTL involves dissection of the spinal cord through a laminotomy open approach (LOA). However, in recent years, the interlaminar approach (ILA) has gained popularity as a minimally invasive surgery. This study compares the effectiveness of the minimally invasive ILA with the conventional LOA in treating FTL.

METHODS

We retrospectively evaluated data on the ILA and LOA for FTL at our center. In total, 103 participants were enrolled, including 55 in the ILA group and 48 in the LOA group.

RESULTS

The ILA required significantly less surgical time and resulted in less blood loss. The improvement rate of symptoms in symptomatic patients was 84%, and for urinary symptoms and abnormal urodynamic study findings, it was 77%. The postoperative maintenance rate for asymptomatic patients was 100%. Postoperative complications of ILA included delayed wound healing in two patients (3.6%).

CONCLUSION

Compared with LOA, ILA offers advantages in terms of shorter operative time and less blood loss, with no significant difference in long-term symptom-improvement rates between the groups.

Surgical Outcomes in Patients Exhibiting Muscular Weakness Postadolescence Due to Tight Filum Terminale

INTRODUCTION

Tight filum terminale is a neurological condition marked by various symptoms, including muscle weakness. There is a notable lack of literature addressing muscle weakness, particularly in cases emerging during adolescence and beyond. The diagnosis is challenging due to a lack of radiological abnormalities, and the literature on its treatment, especially untethering, in adults is limited. This study aims to evaluate the effectiveness of untethering in improving muscle weakness and other symptoms in postadolescent patients diagnosed with tight filum terminale.

METHODS

A retrospective analysis was conducted on seven postadolescent patients diagnosed with tight filum terminale and presenting muscle weakness who underwent untethering at our institution between January 2018 and August 2022. Patients were monitored for muscle strength improvement, lumbar and lower extremity pain, and bowel and bladder dysfunction (BBD) after untethering.

RESULTS

Muscle weakness improved in all cases after untethering, with a mean duration of 9.1 weeks for the improvement. Patients unable to walk independently regained mobility in an average of 22.3 weeks. Lumbar and lower limb pain improved in all cases within an average of 8.1 weeks, while BBD improved in six of the seven cases within an average of 1.9 weeks.

CONCLUSIONS

Our findings suggest that untethering is an effective surgical intervention for postadolescent patients diagnosed with tight filum terminale and presenting muscle weakness.

Distinctive Characteristics of Thoracolumbar Junction Region Stenosis

STUDY DESIGN

Retrospective case series and systemic literature meta-analysis.

BACKGROUND

Thoracolumbar junction region stenosis produces spinal cord compression just above the conus and may manifest with symptoms that are not typical of either thoracic myelopathy or neurogenic claudication from lumbar stenosis.

OBJECTIVE

As few studies describe its specific pattern of presenting symptoms and neurological deficits, this investigation was designed to improve understanding of this pathology.

METHODS

A retrospective review assessed surgically treated cases of T10-L1 degenerative stenosis. Clinical outcomes were evaluated with the thoracic Japanese Orthopedic Association score. In addition, a systematic review and meta-analysis was performed in accordance with guidelines provided by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA).

RESULTS

Of 1069 patients undergoing laminectomy at 1477 levels, 31 patients (16M/15F) were treated at T10-L1 a mean age 64.4 (SD=11.8). Patients complained of lower extremity numbness in 29/31 (94%), urinary dysfunction 11/31 (35%), and back pain 11/31 (35%). All complained about gait difficulty and objective motor deficits were detected in 24 of 31 (77%). Weakness was most often seen in foot dorsiflexion 22/31 (71%). Deep tendon reflexes were increased in 10 (32%), decreased in 11 (35%), and normal 10 (32%); the Babinski sign was present 8/31 (26%). Mean thoracic Japanese Orthopedic Association scores improved from 6.4 (SD=1.8) to 8.4 (SD=1.8) ( P <0.00001). Gait subjectively improved in 27/31 (87%) numbness improved in 26/30 (87%); but urinary function improved in only 4/11 (45%).

CONCLUSIONS

Thoracolumbar junction stenosis produces distinctive neurological findings characterized by lower extremity numbness, weakness particularly in foot dorsiflexion, urinary dysfunction, and inconsistent reflex changes, a neurological pattern stemming from epiconus level compression and the myelomeres for the L5 roots. Surgery results in significant clinical improvement, with numbness and gait improving more than urinary dysfunction. Many patients with thoracolumbar junction stenosis are initially misdiagnosed as being symptomatic from lumbar stenosis, thus delaying definitive surgery.

The discrepancy in triggered electromyography responses between fatty filum and normal filum terminale

BACKGROUND

Functional role of filum terminale (FT) was not well studied though it contains structure basis for nerve impulse conduction. We aimed to explore the possible functions of the FT from the perspective of triggered electromyography (EMG) during surgery.

METHODS

We retrospectively reviewed intraoperative neurophysiological monitoring data from pediatric patients who underwent intradural surgeries at the lumbar level in Shanghai Children's. Hospital from January 2018 to March 2023. Altogether 168 cases with complete intraoperative neurophysiological recordings of the FT were selected for further analysis. Triggered EMG recordings of the filum originated from two main types of surgeries: selective dorsal rhizotomy (SDR) and fatty filum transection.

RESULTS

96 cases underwent SDR and 72 cases underwent fatty filum transection. Electrical stimulation of the FT with fatty infiltration did not elicit electromyographic activity in the monitored muscles with the maximum stimulus intensity of 4.0 mA, while the average threshold for FT with normal appearance was 0.68 mA, and 89 out of 91 FT could elicit electromyographic responses in monitored channels. The threshold ratio of filum to motor nerve roots at the same surgical segment was significantly higher in patients with fatty filum, and a cut-off point of 21.03 yielded an area under curve of 0.943, with 100% sensitivity and 85.71% specificity.

CONCLUSION

Filum with normal appearance can elicit electromyographic activity in the lower limbs/anal sphincter similar to the performance of the cauda equina nerve roots. The threshold of fatty filum is different from that of normal appearing FT. Triggered EMG plays an important role in untethering surgeries.

Fibrofatty filum terminale: long-term outcomes from a Singapore children's hospital

OBJECTIVE

The role of prophylactic detethering a fibrofatty filum terminale (FFT) remains equivocal. Furthermore, long-term studies focusing on urological outcomes are sparse. The aims of this study were to present an institutional experience on the perioperative and long-term outcomes of FFT surgery and to assess for factors that contribute to postoperative clean intermittent catheterization (CIC).

METHODS

This was a single-institution, retrospective study conducted over a 20-year period. Patients younger than 19 years of age who underwent surgery for FFT were included. Variables of interest included patient demographics, clinical presentation, radiological findings, postoperative complications, and long-term need for CIC. Outcomes were measured using the Necker functional score and modified Hoffer Functional Ambulation scale score at 3, 6, and 12 months postdischarge.

RESULTS

A total of 164 surgeries were performed for FFT from 2000 to 2020. The median age at surgery was 1.1 years, and the mean follow-up duration was 8.3 years. There were 115 patients (70.1%) who underwent prophylactic-intent surgery and 49 patients (29.9%) who underwent therapeutic-intent surgery. The proportion of therapeutic-intent surgeries increased significantly with age percentiles (0-20th, 21.9%; 20th-40th, 9.1%; 40th-60th, 18.2%; 60th-80th, 36.4%; and 80th-100th, 63.6% [p < 0.001]). Thirty patients (18.3%) had an associated syndrome, the most common (n = 19, 11.6%) being VACTERL (vertebral defects, anal atresia, cardiac defects, tracheo-esophageal fistula, renal anomalies, and limb abnormalities). Forty-eight patients (29.3%) had an associated malformation (anorectal anomaly = 37, urogenital anomaly = 16, and sacral anomaly = 3). Cutaneous manifestation was the most common presentation (n = 96, 58.5%), followed by lower-limb neurological deficits (n = 21, 12.8%). A low-lying conus was present in 36.0% of patients (n = 59), and 16.5% had an associated syrinx (n = 27). There were 26 patients (18.8%) with an abnormal preoperative urodynamic study. Three patients (1.8%) had postoperative complications that required repeat surgery. There were no cases of CSF leakage. One patient (0.6%) developed retethering requiring another surgery. Postoperative CIC was required in 11 patients (6.7%). Multivariable analyses showed that an abnormal preoperative urodynamic study (adjusted OR 5.5 [95% CI 1.27-23.9], p = 0.023) and having an intraspinal syrinx (adjusted OR 5.29 [95% CI 1.06-26.4], p = 0.042) were associated with the need for CIC.

CONCLUSIONS

The authors' results demonstrate that detethering surgery for FFT is a relatively safe procedure and can be performed prophylactically. Nonetheless, the risks of postoperative CIC should be emphasized during the preoperative counseling process.

Minimal invasive interlaminar approach for untethering of fatty filum terminale in pediatric patients - how I do it

BACKGROUND

Fatty filum terminale is a form of spinal dysraphism and a third of all patients develop symptoms such as sensory, motor, and urinary impairment. Early surgery at 6 months has the advantage that the bone density is still soft, and the patients are not ambulatory yet, promoting faster healing.

METHOD

We present our minimal invasive surgical technique for FFT untethering.

CONCLUSION

Due to the low complication rate and the potentially high benefit of surgery, prophylactic untethering is recommended.

Effect of untethering on occult tethered cord syndrome: a systematic review

BACKGROUND AND OBJECTIVES

Despite the evident clinical, neurological, orthopedic, and urodynamic dysfunctions, neuroanatomic imaging is normal in patients with occult tethered cord syndrome (OTCS). Therefore, the diagnosis of OTCS can be very complex. In this regard, this systematic review aimed to determine the main clinical features (i.e. neurological, musculoskeletal, and urological abnormalities) and improvement rates of these symptoms in patients with OTCS after the section of the filum terminale (SFT).

MATERIALS AND METHODS

All the papers published in three electronic databases, namely Google Scholar, PubMed, and Web of Science, were searched for the purposes of this study. The searching process started on 15 October and lasted until 9 November 2020. Eventually, 10 reports were found about the clinical outcomes of SFT for the management of the OTCS.

RESULTS

The included studies were carried out on a total of 234 patients with OTCS, all of whom had undergone SFT. Evaluation of urologic symptoms revealed that 40-100% of patients with OTCS suffered from urinary instability. Moreover, its improvement rate after SFT was estimated at 59-100%. Evaluation of neurological symptoms indicated that 25-69% of patients with OTCS suffered from back/leg pain, And its improvement rate, the symptoms of back/leg pain of all patients were resolved or improved after SFT. Lower extremity weakness was found in 9-40% of patients with OTCS which was resolved or improved after SFT in about 25-100% of patients. Nevertheless, surgical indications for occult tight filum terminale syndrome remain controversial.

CONCLUSION

Although it seems that the SFT in OTCS patients is promising in treating neurologic, orthopedic and urological symptoms, usage of surgical untethering for patients with OTCS is a controversial issue. Clinical evaluation and urodynamic testing can be used to identify patients with OTCS. However, a multidisciplinary diagnostic work-up is strongly recommended for every child with OTCS.

A critical analysis of surgery for occult tethered cord syndrome

INTRODUCTION

Tethered cord syndrome (TCS) is an amalgamation of neurological, urological, orthopedic, and dermatologic signs and symptoms with radiographic evidence of a thickened filum and low-lying conus. Surgical sectioning of the filum and disconnection of any tethering entities such as dermal sinus tracts or lipomas has been shown to improve outcomes. The manifestation of TCS symptoms in the absence of a low-lying conus has been referred to as occult tethered cord syndrome (OTCS) and is much less well reviewed in the literature. To date, there has only been one randomized controlled trial examining the effect of intervention in OTCS; therefore, contemporary data is often elicited from limited cohorts.

OBJECTIVE

To perform a comprehensive literature review of management in OTCS and evaluate treatment response rates to sectioning of the filum terminale.

RESULTS

Seventeen papers met inclusion criteria for our review. Sample sizes ranged from 8 to 60 children, and results were mixed, often dependent on study design, definition of typical OTCS symptoms, and follow-up intervals. Symptomatic improvement was observed in > 50% of patients for all but one study; however, the recurrence rates were highly variable.

CONCLUSION

The data regarding the efficacy of surgical treatment in OTCS is mixed and merits more rigorous scientific examination with strict and clear parameters regarding symptomatic operationalization and follow-up time points to monitor for TCS recurrence.

Features of the Filum Terminale in Tethered Cord Syndrome with Focus on Pathology

Objective

Filum transection is one of the most commonly performed operative procedure in pediatric neurosurgery. However, the clinical and pathological features as well as the surgical indication are not well-established. This study aimed to analyze the characteristics of patients who underwent transection of the filum during the last 10 years in a single institute.

Methods

A total of 82 patients underwent transection of the filum during the period. As a general rule, we performed the transection in patients who are symptomatic or have abnormality in the urologic or neuromuscular evaluations. There were exceptions as asymptomatic patients who only fit the definition of thickened filum (width greater than 2.0 mm or conus level below L3 vertebral body) were operated by parent’s wish or surgeon’s preference according to radiological findings, etc.

Results

Seventy-six out of 82 patients had fibrous tissue in the pathologic specimen of filum. Interestingly, patients who had glial cells were more correlated with no preoperative syrinx, and no progression of syrinx even for those who did have syrinx initially. Also, larger percentage of symptomatic patients had peripheral nerve twigs than asymptomatic patients. No difference in conus level or thickness of filum was found between patients with or without preoperative syrinx. Significantly more patients with syrinx (56%) were chosen to be operated without any symptom or abnormality in study i.e., solely based on radiological findings than those without syrinx (21%). The surgical outcome for syrinx was favorable, as all but one patient had either improved or static syrinx. The exceptional case had increase in size due to the upward displacement of the proximal end of the cut filum.

Conclusion

This study evaluated the pathological, clinical, radiological features of patients who underwent transection of the filum. Interesting correlations between pathological findings and clinical features were found. Excellent outcome regarding preoperative syrinx was also shown.

Is the Postoperative Horizontal Decubitus Position Following Transection of a Tight Filum Terminale in Pediatric Patients Necessary? - A Retrospective Cohort Study

After untethering surgery of a tethered spinal cord of a tight filum terminale, patients are usually kept in the horizontal decubitus position to prevent cerebrospinal fluid (CSF) leakage. However, the optimal period for keeping these patients in this position has not been established yet. Surgical results in two groups of pediatric patients with a tight filum terminale were retrospectively analyzed. Group A was maintained in the horizontal decubitus position for 72 h and group B was managed without being kept in this position postoperatively. A total of 313 patients underwent sectioning of a tight filum terminale. Of these patients, 144 were maintained horizontally for 72 h postoperatively (group A) and 169 were managed without this position (group B). Among the patients who were maintained horizontally for 72 h, one (0.7%) developed pseudomeningocele. No patients experienced CSF leakage in this group. Among the patients who were not horizontal, one (0.6%) developed CSF leakage and one (0.6%) developed pseudomeningocele. Maintaining patients without restriction of their position does not appear to change the rate of postoperative CSF leakage or pseudomeningocele. This suggests that maintaining patients horizontally after transection of a tight filum terminale is not necessary for preventing CSF leakage.

Oculo-Auriculo-Vertebral Dysplasia With Craniocervical Instability and Occult Tethered Cord Syndrome. An Addition to the Spectrum? First Case Report and Review of the Literature

Oculo-auriculo-vertebral spectrum (OAVS) is an uncommon congenital disorder of abnormal development of the first and second pharyngeal arches. This spectrum is characterized by craniofacial microsomia, epibulbar dermoids, ear abnormalities, renal and cardiac defects, and a wide range of vertebral segmentation and formation disorders. Frequently, the cervicothoracic spine is involved. Only recently, the morbidity attributed to the spinal abnormalities has gained attention. Strategy and timing of spine surgery has become increasingly important in patients with OAVS. Here, we report a case of OAVS with characteristic vertebral cervical and thoracic involvement and its sequelae requiring multiple spinal procedures, further complexed by an unprecedented occult tethered cord syndrome, which was successfully treated by surgical detethering. In this context, the recent literature on spinal anomalies is reviewed.

Pediatric tethered cord release: an epidemiological and postoperative complication analysis

Background

Tethered cord release (TCR) is a common procedure in pediatric neurosurgery. Despite a reputation for being relatively safe, the risk factors for postoperative complications are poorly understood.

Methods

In this study, the American College of Surgeons-National Surgical Quality Improvement Program Pediatric Database (ACS-NSQIP-P) was reviewed to identify the demographics, risk factors, and 30-day postoperative complications for tethered cord release using univariate and multivariate analysis. A detailed analysis of reasons for readmission and reoperation was also performed.

Results

Three thousand and six hundred eighty-two pediatric patients were studied. Males undergoing TCR were younger (5.6 vs. 6.1 years) and had a higher rate of pre-operative comorbidities but lower 30-day complication rate versus females. Patients who later developed complications were more likely to require a microscope intraoperatively, had longer operative times, and worse preoperative American Society of Anesthesiologists (ASA) class.

Conclusions

Despite being a relatively safe procedure, TCR in the pediatric population carries a finite risk of complications. In this large, international database study, males were found to have a greater number of risk factors prior to TCR, while females exhibit a higher risk of developing postoperative complications. This paper provides a large sample size of multi institutional pediatric patients undergoing TCR and may serve as a contemporary "snapshot" for future studies.

Caudal cell mass developmental aberrations: an imaging approach

The objective of this review is to describe antenatal and postnatal imaging criteria, which allow diagnosis and aid workup, prognostication and treatment of developmental anomalies of the caudal cell mass. The lower spinal cord (conus medullaris), filum terminale and inferior lumbar and sacral nerve roots develop from the caudal cell mass, a remnant of the embryologic primitive streak composed of undifferentiated pluripotential cells. Anomalous caudal cell mass development can manifest as tight filum terminale, caudal dysgenesis, terminal myelocystocele, anterior sacral meningocele or sacrococcygeal teratoma. Lower spinal cord development occurs simultaneously and in topological proximity to the developing lower gastrointestinal and genitourinary tracts, leading to coexistent malformations. We review the embryology of the caudal cell mass, describe the role of antenatal and postnatal imaging for diagnosing, staging, prognosticating and guiding intranatal or postnatal intervention for developmental anomalies of this region and briefly discuss clinical manifestations and treatment goals and strategies. An overview of antenatal imaging diagnosis of associated multisystem abnormalities will be provided where applicable.

Duration of the horizontal decubitus position for prevention of cerebrospinal fluid leakage following transection of a tight filum terminale

OBJECT

The untethering of a tethered spinal cord in patients with a tight filum terminale is a relatively simple procedure that can prevent or improve neurological symptoms. Postoperatively, patients are usually kept in the horizontal decubitus position to prevent a CSF leak. However, the optimal period for keeping patients flat has not been determined yet. The authors compared 2 cohorts with different periods of horizontal decubitus; one with 72 hours and the other with 8 days.

METHODS

The authors retrospectively analyzed surgical results in 2 cohorts of pediatric patients who had tethered spinal cord with a tight filum terminale. One cohort was maintained flat for 8 days and the other cohort for 72 hours postoperatively. The patients' charts were reviewed for demographic data, clinical presentation, surgical therapy, and clinical course.

RESULTS

Three hundred fifty-four patients underwent sectioning of a tight filum terminale. Of those, 238 were kept lying flat for 8 days postoperatively, and 116 were maintained flat for 72 hours. Magnetic resonance imaging was performed 1 to 2 weeks after the surgery. None of the patients in either cohort developed a CSF leak. Pseudomeningocele, which was confirmed by MRI, developed in 1 patient who had been kept flat for 8 days. The occurrence rates of a CSF leak and pseudomeningocele were not significantly different in either cohort.

CONCLUSIONS

Keeping patients flat for longer than 72 hours did not change the rate of postoperative CSF leakage or pseudomeningocele. Seventy-two hours or less would be an appropriate period for maintaining patients flat after transection of a tight filum terminale.

The effect of untethering on urologic symptoms and urodynamic parameters in children with primary tethered cord syndrome

OBJECTIVE

To evaluate urinary system symptoms (USSs) and urodynamic parameters (UPs) before and after untethering in children with primary tethered cord syndrome (pTCS).

METHODS

USSs and UPs of patients undergoing untethering for pTCS during the period January 2008-July 2012 were evaluated preoperatively and at the postoperative third and 12th months. For analysis, patients were separated into 4 groups according to the presence of USSs: group 1, USSs preoperative positive and postoperative negative; group 2, USSs preoperative positive and postoperative positive; group 3, USSs preoperative negative and postoperative positive; group 4, USSs preoperative negative and postoperative negative. Preoperative and postoperative USSs and UPs were compared.

RESULTS

Forty patients (average age, 7.2 years, follow-up of 2.8 years) were included. There were 13 patients in group 1, 11 in group 2, 3 in group 3, and 13 in group 4. All patients showed improvement when preoperative and postoperative USSs and UPs were compared. There was no correlation between USSs and UPs, both preoperatively and postoperatively. USSs and UPs at the postoperative third and 12th months were similar. Patients with no USS showed the most significant improvement in UP after untethering.

CONCLUSION

Our study has demonstrated that untethering in patients with pTCS improves urologic symptoms and UPs. However, there is no correlation between improvement in symptoms and urodynamic findings. Urodynamic changes are similar at the postoperative third and 12th months. As the most significant improvement was seen in patients without USSs, it is important that these patients undergo urodynamic studies preoperatively and postoperatively.

Early identification of tethered cord syndrome: a clinical challenge

Tethered cord syndrome (TCS) is a progressive clinical condition that arises from excessive spinal cord tension. The clinical signs and symptoms of TCS may be cutaneous, neurologic, musculoskeletal, genitourinary, and/or gastrointestinal. Patients also may be asymptomatic, which does not exclude the diagnosis of TCS. Although the exact etiology is unknown, early identification and lifelong surveillance or surgical treatment is an essential component of patient management. In this article we review the pathophysiology, various etiologies, clinical presentation, and long-term sequelae of TCS. This information will help pediatric nurse practitioners identify TCS early and anticipate the patient's needs and management requirements.

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

OBJECT

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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