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EDITORIAL
Year : 2016  |  Volume : 11  |  Issue : 2  |  Page : 97-98
 

Asymptomatic lipomas: Is there a debate?


Editor-in-Chief, Department of Neurosurgery, VIMS, Kolkata, West Bengal, India

Date of Web Publication3-Aug-2016

Correspondence Address:
Sandip Chatterjee
Park Clinic 4, Gorky Terrace, Kolkata - 700 017, West Bengal
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/1817-1745.187617

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How to cite this article:
Chatterjee S. Asymptomatic lipomas: Is there a debate?. J Pediatr Neurosci 2016;11:97-8

How to cite this URL:
Chatterjee S. Asymptomatic lipomas: Is there a debate?. J Pediatr Neurosci [serial online] 2016 [cited 2019 Nov 15];11:97-8. Available from: http://www.pediatricneurosciences.com/text.asp?2016/11/2/97/187617


The term "tethered cord" has been controversial ever since Lichtenstein's proposal [1] in 1940 because it referred to a visual anomaly without considering the pathophysiological changes. A "tethered cord" refers to a pathological fixation of the spinal cord. The "tethered cord syndrome" (TCS) may or may not result from this anomaly. This syndrome results from tethering, and it is said to occur when there are progressive neurological, urological, or orthopedic symptoms. [2],[3],[4] Knowledge of the anatomy of this condition has expanded manifold since the availability of magnetic resonance imaging. In no condition with tethered cord, there has been such an intense debate about prophylactic surgery for asymptomatic children than children with lipomas.

The controversy in this condition has revolved around the indication and timing of surgery. Some authors have proposed that surgical detethering guarantees a good long-term outcome. [5],[6],[7] Others have questioned the wisdom of prophylactic release, stating that progression of symptoms will occur in spite of surgical release. [8],[9] This is a review of the current thoughts on the matter, and to question whether there is a debate at all today.

Yamada and Won [10] categorized tethered lesions into three categories: (1) True TCS, associated with an inelastic filum with or without cord elongation or filum thickening, caudal lipomyelomeningoceles (LMMCs) and sacral myelomeningoceles (MMCs); (2) a combination of the lesion above the cord fixation (TCS) and additional local lesion related to MMCs or dorsal and large transitional LMMCs; (3) patients without typical signs and symptoms of TCS despite the anatomical appearance of cord tethering.{Figure 1}

The same author later [11] proposed a clinical classification: (1) True TCS, (2) partial TCS, (3) nonstretch-induced disorder with symptomatology and anomalies similar to TCS, and (4) a large MMC in the high lumbar area. Category 1 patients had the best surgical outcome, Category 2 only had recovery in deficits which correlated with stretch-induced dysfunction, Category 3 patients had pain relief but no neurological improvement, and Category 4 patients after surgery had no change in neurological signs. Clearly, it would appear that Category 1 and 2 would benefit from surgery, Category 3 would lead to unpredictable results, and in Category 4, surgery would be unpredictable as much as it would be impossible to hazard a guess as to the results of such a release. Extrapolating to the classification of congenital lipomas proposed by Pang, these are classified into the following types: Dorsal, terminal, transitional, and chaotic. Hence, the terminal would represent Type 1 with good surgical results in terms of neurological recovery, the dorsal and transitional would represent Type 2 with unpredictable recovery of function, and the chaotic would definitely be Type 3 where untethering may make no difference to outcome.

The problem is, however, a little more, as two more considerations enter into the equation: (1) How much of the pathophysiological changes are reversible after surgery and (2) what is the morbidity of the surgical intervention itself?

To understand the first question, we have to appreciate that in lipomas, like in other tethering lesions, there is impairment of the oxidative metabolism and there is electrophysiological dysfunction. [12],[13],[14] Hence, how much of the cord changes are reversible after surgery is difficult to be certain about. Regarding the second question, Pierre-Kahn [15] demonstrated that in asymptomatic lipomas of the conus, 25% of the patients deteriorated within a mean period of 4.4 years after surgery. At 9 years, the actual risks of deterioration, as determined by the Kaplan-Meier method, were 33% for conservatively treated patients and 46% for the surgically treated patients. The suggestion by this group was clear risks of surgical intervention for asymptomatic conus lipomas, which was higher with the so-called "prophylactic" intervention! Yet, publications by Pang et al. have recommended prophylactic surgery for all dorsal, terminal, and transitional lipomas. [16]

Although at the outset there may seem to be a debate between the two groups on either side of the Atlantic, a little analysis reveals the following facts about the two publications: (1) Pierre-Kahn group from Paris performed partial resection of lipomas with considerable morbidity and neurological deterioration, whereas in Pang's own series, the results of this treatment were also very poor. What was different in Pang's later series? First, he performed "total" resection of the lipomas, using the "white line" as a guide to the plane between the cord and the lipoma. Second, he always recommended intraoperative neurophysiological monitoring. Hence, in case of dorsal and terminal lipomas, it would appear that complete resection of the lipoma provides the best results, and indeed, the best insurance against delayed retethering! The current data from Paris suggest that their results are better with total removal of the lipomas. [17] In another recent publication, Talamonti et al. [18] seem to also favor prophylactic surgery in all but transitional lipomas.

Neurological signs are often used as a guide to prognosis and treatment as in the grading system of lipomas described by Hoffman et al.[19] Here, Grade 0 and Grade 1 patients who have large conus lipomas which are difficult to completely remove are often best treated with supervised neglect. Fat is soft and elastic, but when the fibrous component of fibroadipose tissue in the filum increases, this may result in excessive cord traction. As regards the growth rate of the spinal cord vis-à-vis that of the vertebral column, if the cord is anchored by an inelastic filum at or below L3 level at the age of 4 or more years, the growth rate of the lumbosacral cord may not match that of the vertebral column, and it is likely to result in unacceptable levels of cord traction. [20],[21]

Where does all this lead us to in the great asymptomatic lipoma debate? The following deductions can be readily made: (1) Asymptomatic lipomas of the filum need early untethering surgery as this procedure carries minimal morbidity. (2) prophylactic is best performed for dorsal and transitional lipomas, provided total removal may be carried out, and for this, intraoperative monitoring is mandatory. (3) If total removal of a lipoma cannot be performed, for example, in a chaotic lipoma, it is best to leave well alone! The same applies to those who are unable to remove in totality any of the other types of lipomas as well. Hence, the great asymptomatic debate seems to be fizzling out today….

 
   References Top

1.
Lichtenstein BM. Spinal dysraphism. Spina bifida and myelodysplasia. Arch Neurol Psychiatry 1940;44:792-809.  Back to cited text no. 1
    
2.
Archibeck MJ, Smith JT, Caroll KL, Davitt JS, Stevens PM. Surgical release of tethered spinal cord: Survivorship analysis and orthopaedic outcome. J Paediatr Orthop 1997;17:773-6.  Back to cited text no. 2
    
3.
Mapstone TB. Management of tethered spinal cord. Neurosurg Q 1994;4:82-91.  Back to cited text no. 3
    
4.
Sharif S, Allcutt D, Marks C, Brennan P. Tethered cord syndrome - Recent clinical experience. Br J Neurosurg 1997;11:49-51.  Back to cited text no. 4
    
5.
Byrne RW, Hayes EA, George TM, McLone DG. Operative resection of 100 spinal lipomas in infants less than 1 year of age. Pediatr Neurosurg 1995;23:182-6.  Back to cited text no. 5
    
6.
Koyanagi I, Iwasaki Y, Hida K, Abe H, Isu T, Akino M. Surgical treatment supposed natural history of the tethered cord with occult spinal dysraphism. Childs Nerv Syst 1997;13:268-74.  Back to cited text no. 6
    
7.
Satar N, Bauer SB, Scott RM, Shefner J, Kelly M, Darbey M. Late effects of early surgery on lipoma and lipomeningocele in children less than 1 year old. J Urol 1997;157:1434-7.  Back to cited text no. 7
    
8.
Pierre-Kahn A, Zerah M, Renier D. Malformative intraspinal lipomas. Neurochirurgie 1995;41:1-134.  Back to cited text no. 8
    
9.
Van Calenbergh F, Vanvolsem S, Verpoorten C, Lagae L, Casaer P, Plets C. Results after surgery for lumbosacral lipoma: The significance of early and late worsening. Childs Nerv Syst 1999;15:439-42.  Back to cited text no. 9
    
10.
Yamada S, Won DJ. What is the true tethered cord syndrome? Childs Nerv Syst 2007;23:371-5.  Back to cited text no. 10
    
11.
Yamada S, Won DJ, Yamada SM. Pathophysiology of tethered cord syndrome: Correlation with symptomatology. Neurosurg Focus 2004;16:E6.  Back to cited text no. 11
    
12.
Yamada S, Sanders DC, Maeda G. Oxidative metabolism during and following ischemia of cat spinal cord. Neurol Res 1981;3:1-16.  Back to cited text no. 12
[PUBMED]    
13.
Kang JK, Kim MC, Kim DS, Song JU. Effects of tethering on regional spinal cord blood flow and sensory-evoked potentials in growing cats. Childs Nerv Syst 1987;3:35-9.  Back to cited text no. 13
[PUBMED]    
14.
Yamada S, Zinke DE, Sanders D. Pathophysiology of tethered cord syndrome. J Neurosurg 1981;54:494-503.  Back to cited text no. 14
[PUBMED]    
15.
Kulkarni AV, Pierre-Kahn A, Zerah M. Conservative management of asymptomatic spinal lipomas of the conus. Neurosurgery 2004;54:868-73.  Back to cited text no. 15
    
16.
Pang D, Zovickian J, Oviedo A. Long-term outcome of total and near-total resection of spinal cord lipomas and radical reconstruction of the neural placode, part II: Outcome analysis and preoperative profiling. Neurosurgery 2010;66:253-72.  Back to cited text no. 16
    
17.
Zerah M, Roujeau T, Catala M, Pierre-Kahn A. Spinal lipomas. In: Özek M, Cinalli G, Maixner W, editors. Spina Bifida: Management and Outcome. Milan: Springer-Verlag; 2008. p. 445-74.  Back to cited text no. 17
    
18.
Talamonti G, D'Aliberti G, Nichelatti M, Debernardi A, Picano M, Redaelli T. Asymptomatic lipomas of the medullary conus: Surgical treatment versus conservative management. J Neurosurg Pediatr 2014;14:245-54.  Back to cited text no. 18
    
19.
Hoffman HJ, Taecholarn C, Hendrick EB, Humphreys RP. Management of lipomyelomeningoceles. Experience at the Hospital for Sick Children, Toronto. J Neurosurg 1985;62:1-8.  Back to cited text no. 19
[PUBMED]    
20.
Sarwar M, Virapongse C, Bhimani S. Primary tethered cord syndrome: A new hypothesis of its origin. AJNR Am J Neuroradiol 1984;5:235-42.  Back to cited text no. 20
[PUBMED]    
21.
Drake JM. Occult tethered cord syndrome: Not an indication for surgery. J Neurosurg 2006;104 5 Suppl: 305-8.  Back to cited text no. 21
    




 

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