Long-term urological outcomes of spinal lipoma after prophylactic untethering in infancy: real-world outcomes by lipoma anatomy

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.

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.

Chaotic lipoma with proximal syrinx -a (not so) rare variant - review of the literature, possible embryology and management

Chaotic lipomas are an extremely rare variant of spinal lipomas. This entity was first defined in 2009 by Pang and colleagues. Not much has been written about this variant. Its characteristic is the haphazard distribution of DREZ (Dorsal root entry zone), nerve roots and placode-lipoma interface. Thus complete/near-total excision of this lesion is quite difficult. We describe a case of chaotic spinal lipoma and elucidate the challenges faced in the management of this entity and review the literature. We performed a thorough systematic review with the keyword 'chaotic', 'Lipomyelomeningocele', 'Complex Lipomyelomeningocele', 'LMMC', 'Lumbar lipoma', 'spinal lipoma' in the google scholar and PUBMED data system for indexed literature on the above topic with no particular time frame. The studies quoted range earliest from 1970 till currently. Additional potential relevant articles were further retrieved through a manual search of references from original reports. Out of 42 studies, a total of 21 publications were selected which could have encountered a chaotic variant, but due to the term introduced only recently in 2009, may have been described differently. Studies encompassing true lipomeningomyelocele were excluded from our review. What we found out? Chaotic lipoma may not be a new entity. The scarce description in literature may be in part due to non-introduction and unclear description of this term earlier. The management of this variant is particularly challenging with basic principles remaining the same. Meticulous near-total excision and placode-lipoma construct are the major obstacles.

Surgery for spina bifida occulta: spinal lipoma and tethered spinal cord

The technical evolution of the surgery for spina bifida occulta (SBO) over the course of a half-century was reviewed with special foci placed on the spinal lipoma and tethered spinal cord. Looking back through history, SBO had been included in spina bifida (SB). Since the first surgery for spinal lipoma in the mid-nineteenth century, SBO has come to be recognized as an independent pathology in the early twentieth century. A half-century ago, the only option available for SB diagnosis was the plain X-ray, and pioneers of the time persevered in the field of surgery. The classification of spinal lipoma was first described in the early 1970s, and the concept of tethered spinal cord (TSC) was proposed in 1976. Surgical management of spinal lipoma with partial resection was the most widely practiced approach and was indicated only for symptomatic patients. After understanding TSC and tethered cord syndrome (TCS), more aggressive approaches became preferred. A PubMed search suggested that there was a dramatic increase of publications on the topic beginning around 1980. There have been immense academic achievements and technical evolutions since then. From the authors' viewpoint, landmark achievements in this field are listed as follows: (1) establishment of the concept of TSC and the understanding of TCS; (2) unraveling the process of secondary and junctional neurulation; (3) introduction of modern intraoperative neurophysiological mapping and monitoring (IONM) for surgery of spinal lipomas, especially the introduction of bulbocavernosus reflex (BCR) monitoring; (4) introduction of radical resection as a surgical technique; and (5) proposal of a new classification system of spinal lipomas based on embryonic stage. Understanding the embryonic background seems critical because different embryonic stages bring different clinical features and of course different spinal lipomas. Surgical indications and selection of surgical technique should be judged based on the background embryonic stage of the spinal lipoma. As time flows forward, technology continues to advance. Further accumulation of clinical experience and research will open the new horizon in the management of spinal lipomas and other SBO in the next half-century.

Analysis of factors affecting permanent clean intermittent catheterization and bladder function after primary neurosurgical repair of lipomyelomeningocele

AIMS

This study was conducted to identify potential risk factors for permanent clean intermittent catheterization (CIC) and incontinence in patients with lipomyelomeningocele (LMMC) and evaluate how LMMC affects bladder function prognosis, measured by urodynamic (UD) score.

METHODS

This retrospective study analyzed the electronic health records of patients who underwent primary neurosurgical repair for LMMC at a single tertiary referral center between January 2012 and December 2016 and were followed at least 3 years after surgery. Data regarding bladder function were obtained from medical records for multiple time points, including before surgery, after surgery but before hospital discharge, 3 months after surgery, and at outpatient visits during follow-up.

RESULTS

This study enrolled 120 patients. At a mean follow-up of 62.6 ± 13.9 months after primary neurosurgical LMMC repair, 22 (18.3%) patients continued to require CIC for bladder emptying, only 7 (31.8%) of whom maintained bladder continence. A multivariate logistic regression model identified age at the time of surgery and the type of LMMC as significant presurgical prognostic risk factors for permanent CIC. In addition, postoperative urinary retention and a UD score greater than or equal to 5 measured 3 months after surgery were identified as significant postsurgical risk factors for permanent CIC and urinary incontinence. A linear mixed model adjusted for age at the time of surgery showed that patients with a transitional or chaotic LMMC type were more likely to experience gradual bladder function decline than patients with other LMMC types.

CONCLUSIONS

This study identified both presurgical (age at the time of surgery, LMMC type) and postsurgical (postoperative urinary retention, UD score greater than or equal to 5 at 3 months postsurgery) risk factors for permanent CIC and urinary incontinence. In addition, LMMC type was identified as a prognostic risk factor for bladder function decline. These results will enhance the current understanding of bladder function outcomes in patients who undergo surgical treatment for LMMC.

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.

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.