|Year : 2016 | Volume
| Issue : 2 | Page : 99-104
Immediate and long-term outcome analysis of lipomeningomyelocele repair in asymptomatic infants in a tertiary care center
Prashant Sadashiv Patil, Abhaya Gupta, Paras L Kothari, Geeta Kekre, Rahul Gupta, Vishesh Dikshit, Kedar Mudkhedkar, Krishna Kesan
Department of Paediatric Surgery, L.T.M.G. Hospital, Sion, Mumbai, Maharashtra, India
|Date of Web Publication||3-Aug-2016|
Prashant Sadashiv Patil
Ward 1A, Paediatric Surgery Ward, L.T.M.G. Hospital, Sion, Mumbai, Maharashtra
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Objective: To analyze immediate and long-term results of lipomeningomyelocele (LMM) repair in asymptomatic patients. Materials and Methods: Seventeen patients of LMM presented to Department of Paediatric Surgery over a period from 2011 to 2015 were evaluated preoperatively by magnetic resonance imaging of whole spine, and pre- and post-operative Ultrasound of kidney, ureter, bladder, and neurosonogram. Surgical procedure involved total excision of lipoma in 15 patients and near total excision in 2 patients. Division of filum terminale could be done in 15 out of 17 patients. Follow-up varied from 1 to 3.5 years (mean 1.9 years). Results: This study included 10 (58.8%) patients of lumbosacral LMM, 5 (29.4%) patients of sacral, and 2 (11.7%) patients of thoracolumbar LMM. About 13 (76.4%) patients were operated before 3 months of age, 2 (23.5%) patients were operated between 3 and 6 months, and two patients were operated between 6 and 11 months. None of the patients had bladder/bowel dysfunction preoperatively. Preoperative lower limb power was normal in all patients. Objective improvement in lower limb motor function was observed in 3 (17.6%) patients and three patients had decreased lower limb power. Two patients developed altered sensations and weakness of lower limb about 2.5-3 years after initial LMM repair. They needed repeat detethering of cord. Two patients had fecal pseudoincontinence, whereas one patient developed constipation. Bowel dysfunction was managed by rectal washouts, and oral laxatives were added if required. One (5.8%) patient of lumbosacral LMM and 1 (5.8%) patient of sacral LMM had urinary incontinence postoperatively. This was managed by clean intermittent catheterization with continuous overnight drainage. Conservative management of bladder and bowel dysfunction was effective in all patients till the last follow-up. Two patients developed hydrocephalus after LMM repair for which low-pressure ventriculoperitoneal shunt was inserted. Wound infection occurred in 1 (5.8%) patient, whereas 7 (41.1%) patients developed seroma in wound which responded to repeated aspirations under aseptic precautions. Conclusion: With total excision of lipoma and division of filum terminale satisfactory outcome for asymptomatic patients of LMM can be achieved. Authors recommend early surgery for LMM even in asymptomatic patients. Patients with residual lipoma and undivided filum terminale should be observed closely for the development of progressive neurological changes.
Keywords: Hydrocephalus, lipomeningomyelocele, tethered cord, ventriculoperitoneal shunt
|How to cite this article:|
Patil PS, Gupta A, Kothari PL, Kekre G, Gupta R, Dikshit V, Mudkhedkar K, Kesan K. Immediate and long-term outcome analysis of lipomeningomyelocele repair in asymptomatic infants in a tertiary care center. J Pediatr Neurosci 2016;11:99-104
|How to cite this URL:|
Patil PS, Gupta A, Kothari PL, Kekre G, Gupta R, Dikshit V, Mudkhedkar K, Kesan K. Immediate and long-term outcome analysis of lipomeningomyelocele repair in asymptomatic infants in a tertiary care center. J Pediatr Neurosci [serial online] 2016 [cited 2020 Jul 4];11:99-104. Available from: http://www.pediatricneurosciences.com/text.asp?2016/11/2/99/187619
| Introduction|| |
Lipomeningomyelocele (LMM) is a form of closed neural tube defect. It is a complex disorder that may present with neurological deficits secondary to the inherent tethered cord. Treatment strategies aim to remove adipose tissue, identify defect in the lumbosacral fascia for the release of the tether, possible release of the filum terminale, preservation of neural elements, and prevention of retethering of the spinal cord.  We present our experience of early repair and follow-up of asymptomatic patients with this lesion.
| Materials and Methods|| |
Patient's age and gender
Seventeen cases were included in this study from August 2011 to July 2015. There were 10 (58.8%) boys and 7 (41.1%) girls. Eight boys and 5 girls were operated before 3 months of age, 1 boy and 1 girl were operated between 3 and 6 months. One boy and 1 girl were operated between 6 and 11 months [Table 1].
Antenatal diagnosis and presenting complaint
Eleven (64.7%) patients had antenatal diagnosis of spinal cord anomaly, 3 (17.6%) patients had not done antenatal scan, whereas another three patients were told they had normal antenatal scans. All the patients presented with complaint of swelling over back, in middle region or lower back-sacral region.
Thirteen (76.4%) patients had cutaneous markers of underlying spinal dysraphism which included 5 (29.4%) patients with skin dimple, 6 (35.2%) patients with diffuse lipomatous swelling over back [Figure 1], and 2 (11.7%) patients with altered colored skin patch. Asymmetric gluteal folds were present in 3 (17.6%) patients. Three 3 (17.6%) patients had scoliosis and two (11.7%) patients had spina bifida with hydrocephalus [Table 2]. Lower limb power and tone was good in all patients and was reassessed postoperatively. Anocutaneous and bulbocavernosus reflexes and anal tone were examined preoperatively and postoperatively in all patients. Head circumference, bladder and bowel function were assessed preoperatively and compared with postoperative findings.
Radiological findings and associated lesions
Ultrasound (USG) of head, kidney, ureter, bladder, USG of skull, and magnetic resonance imaging (MRI) of spine [Figure 2] were done in all patients.
Patients were operated in prone position under general anesthesia with all the pressure points well protected. An elliptical or oval skin incision was made around the central most prominent part of lipomatous swelling, and skin flaps were raised in subcutaneous plane. Dissection was done all around the central lipomatous component, reaching up to the lumbosacral and thoracolumbar fascia [Figure 3]. Dura was opened cranially and caudally from the site of defect and intradural component of lipoma was excised. Detethering of cord was done. Laminotomy was done when felt required. Filum terminale was identified and divided at its lower and lowermost visible end. Dura was closed primarily using 5-0 Prolene without the use of synthetic material in all cases followed by closure of lumbosacral or thoracolumbar fascia over it using Prolene 5-0 [Figure 4]. Average operative time was 90 min and average blood loss was 15 cc. Bipolar cautery was used after subcutaneous dissection. In doubtful cases, nerve locator was used to differentiate neural tissue from connective tissue and sharp dissection with scissors was preferred. Minivac suction drain was used in 11 (64.7%) cases with large dead space in subcutaneous plane. Sutures were removed after 8-10 days and patient was followed regularly [Figure 5].
|Figure 3: Intraoperative photo of lipomyelomeningocele showing neural tissue with adherent lipomatous component|
Click here to view
Operative findings concurred with MRI report in all cases. Laminotomy at cranial end was required in 3 (17.6%) patients of lumbosacral LMM for complete detethering and for two patients of sacral LMM at caudal end for division of filum terminale. Total excision of lipoma was achieved in 15 patients. Filum terminale was identified as a white fibrous tissue in midline distinctly separate from nerve fibers in 15 patients. We have observed that filum terminale is not associated with a bunch of nerve fibers in the immediate vicinity, and it can be confirmed by nerve locator. Filum terminale was divided in 15 patients. Two patients had large lipomatous component adherent to neural placode and filum terminale. Near total excision was done in these patients. As filum terminale could not be identified distinctly, it was not divided.
| Results|| |
Immediate postoperative complications
Four (23.5%) patients of lumbosacral LMM and 1 (5.8%) patient of sacral LMM had transient altered bladder and bowel function after operative procedure in the form of frequent urinary dribbling and tendency to constipate. This recovered in 2 weeks. Six (35.2%) patients of lumbosacral LMM and 3 (17.6%) patients of sacral LMM had reduced lower limb power in the immediate postoperative period which became normal by 5 th postoperative day. These patients were given methylprednisolone in pulse therapy for 3 days after operative procedure. One patient had surgical site infection which required local debridement and secondary suturing under antibiotic cover. Seven (41.1%) patients had persistent seroma formation after removal of suction drain. Seroma was aspirated under aseptic conditions on outpatient department basis, and oral antibiotics were given. Perioperative period was otherwise uneventful [Table 3].
Late postoperative complications
Patients were followed up monthly initially for 3 months, and later follow-up varied according to patient profile. Patients were examined for any increase in head size to detect the development of hydrocephalus. Lower limb power and sensations were assessed by muscle charting and clinical examination.
Three (17.6%) patients had decreased lower limb power after surgical procedure. These patients were managed with regular physiotherapy and Faradic muscle stimulation. Custom made footwear was designed by occupational therapist. Two (11.7%) of these children actually could walk with support at the age of 15 and 19 months. One (5.8%) patient had decreased sensations over plantar aspect of foot and one patient suffered from altered sensations over dorsum and lateral side of foot. Parents of both patients have been taught foot care.
Two (11.7%) patients had developed urinary incontinence. Clean intermittent catheterization in the daytime with continuous overnight drainage could achieve dry interval period of 3-4 h in both patients. One patient had developed constipation which responded to diet modifications (high residue, low carbohydrate diet) and oral laxatives. Two Patients with fecal pseudoincontinence were managed with rectal washouts [Table 4].
Two (11.7%) patients developed mild to moderate hydrocephalus within 3 months of initial procedure. Low-pressure slit and spring ventriculoperitoneal shunt were inserted in both patients. One (5.8%) patient had shunt complication in the form of surgical site infection which required antibiotic treatment [Table 5].
Two (11.7%) patients who initially had subtotal excision of lipoma and undivided filum terminale developed decreased sensations over lateral and plantar aspect of foot and weakness at ankle joints about 2.5-3 years after initial procedure. MRI revealed retethering of cord with residual lipoma at S1-S3 level. Both the patients were reoperated, and detethering was done. These patients are on regular follow-up since 6 months. Both the patients have intact sensation to painful stimulus after repeat operation, but fine touch sensations cannot be felt. Pressure, vibration, and temperature sensations can be felt to some extent. Power at ankle joint has not improved much.
| Discussion|| |
Closed spinal dysraphism includes lipomyelomeningocele, diastematomyelia, and spina bifida occulta which have covered neural tissue.  Embryological abnormalities during primary neurulation account for closed spinal dysraphism. Spinal dysraphism that arises from premature separation of epithelial ectoderm from the neural ectoderm (process called disjunction) result in fusion of the spinal cord with fatty elements, the most common of which is an LMM.  LMM is embryologically associated with tethered cord. It can also be associated with other abnormalities such as genitourinary tract anomalies (4.1%), split cord malformations (3.1%), associated dermal sinuses (3.1%), dermoid or epidermoid cysts (3.1%), diastematomyelia (3.1%), terminal hydromyelia (3.1%), anal stenosis (1.0%), and Down syndrome (1.0%).  The incidence of LMM has been found to range between 0.3 and 0.6 per 10,000 live births.  Maternal dietary folic acid supplementation has been found to reduce the risk of neural tube defects among offspring.  However, this has not been observed for LMM  implying that the pathogenesis of LMM is embryologically different from that of other neural tube defects. LMM usually presents as a subcutaneous lipoma that is commonly located in the lumbar or sacral region.  Subcutaneous lipoma is restricted by the defect in the lumbodorsal fascia limiting the upward movement of the conus medullaris during axial growth and thus may lead to progressive neurological and urinary deficits.  Progressive conus tethering and injury to nervous tissue contributes to neurological dysfunction with increasing age in untreated patients. A logarithmic association has been found between neurological dysfunction and increasing patient age and is caused by increased stretch on the spinal cord with axial growth spurts.  In a series by Hoffman et al.,  62.5% of patients were neurologically asymptomatic before 6 months of age, whereas only 29.3% were asymptomatic after 6 months of age. Decreased perfusion secondary to stretch on the spinal cord, increased mass effect from progressive deposition of fat, and stretching effects on the spinal cord also contribute to progressive neural damage.  The disease progression can result in bladder and bowel dysfunction resulting in frequent urinary tract infections, urinary and fecal incontinence, or constipation. Lower limb symptomatology includes leg length discrepancy, foot deformities, gait abnormalities, scoliosis, spasticity, and back and leg pain.  Patient with a neurogenic bladder frequently presents with a change in micturition pattern.  Abnormality of bladder function may be the only indirect indicator of neurological injury in these children.  Surgery is the mainstay of treatment. The lipomatous component is in close relation with the neural tissue, which may limit complete resection of the lipomatous component without causing neurological injury.  Cautery, laser, and ultrasonic aspiration have been used to excise lipoma. Intraoperative neurophysiological monitoring is recommended to facilitate safe resection of lipomatous components and detethering of the spinal cord.  Duraplasty may be added to cover large defect.
Role of surgery before the onset of neurological symptoms is a debatable issue. In one study, the actual risks of deterioration were 33% for the conservatively treated patients and 46% for the surgically treated patients. The incidences and patterns of neurological deterioration seemed to be very similar, regardless of whether early surgery was performed.  Outcomes after surgery for lipomyelomeningocele correlate with preoperative function of the patient. For patients of LMM with established neurological deficits surgery is associated with major risks and is of questionable long-term efficacy.  A series of eighty patients by Kanev et al. showed that 92.1% of children with a normal preoperative examination had no neurological deficits or bladder dysfunction at long-term follow-up, and all had normal bladder function. However, children with preoperative bowel and bladder paralysis did not show improvement after LMM repair though patients from this subgroup showed improvement in sensory and motor function of lower limbs. Beneficial role of surgery before the development of neurological deficits has been highlighted by another study which concluded that most of the patients benefit only to some extent even after surgery once deficits developed. 
Spinal cord retethering following lipomyelomeningocele repair has been found to be between 10% and 20%. , Back pain, deterioration of lower extremity function, worsening of urological, and bowel function indicate retethering. It develops 3-8 years after the initial surgery.  It is the author's premise that if the LMM is not repaired early (before development of neurological symptoms), patient will present with symptoms at an advanced stage when the role of surgery is limited with respect to reversing the established neurological deficits; in fact, surgery may be more hazardous in these patients. Patients developing retethering symptoms after LMM repair are not as much at risk of neurological sequelae as patients with LMM presenting primarily at later age.
This study found transient neurological dysfunction in five patients which normalized in 2 weeks suggesting acute neuronal injury inflicted during surgery. Retrospective analysis of these patients showed that all of them had significant lipoma component adherent to neural placode, and this required prolonged dissection. Three (17.6%) patients had urinary and fecal incontinence over long term; conservative management was effective in all of them; three patients had decreased lower limb power, two patients had decreased foot sensations, 2 (11.7%) patients developed symptoms of retethering which required intervention. These patients had subtotal excision of lipoma and undivided filum terminale.
| Conclusion|| |
Lipomyelomeningocele is a form of closed neural tube defect with unclear predisposing factors. Due to the risk of worsening neurological, urological, and bowel function secondary to a tethered spinal cord, it continues to be important to identify this condition for timely intervention. Results of this study have shown that surgery for LMM is safe and if done with correct technique achieves its purpose of preventing neurological deterioration in asymptomatic patients. We recommend total excision of lipoma with division of filum terminale and close follow-up of patients with residual lipoma and undivided filum terminale to pick up early signs of neurological deterioration. As the results of surgery in patients with established neurological insult are not as good as those in preoperatively asymptomatic patients, it is important to counsel and encourage parents regarding early repair in diagnosed cases.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]