Arachnolysis or Cerebrospinal Fluid Diversion for Adult-Onset Syringomyelia? A Systematic Review of...
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Arachnolysis or Cerebrospinal Fluid Diversion for Adult-Onset Syringomyelia? ASystematic Review of the Literature
George M. Ghobrial, MD Richard T. Dalyai, MD Mitchell G. Maltenfort, PhD SrinivasK. Prasad, MD James S. Harrop, MD Ashwini D. Sharan, MD
PII: S1878-8750(14)00590-7
DOI: 10.1016/j.wneu.2014.06.044
Reference: WNEU 2437
To appear in: World Neurosurgery
Received Date: 10 September 2013
Revised Date: 9 June 2014
Accepted Date: 24 June 2014
Please cite this article as: Ghobrial GM, Dalyai RT, Maltenfort MG, Prasad SK, Harrop JS, Sharan AD,Arachnolysis or Cerebrospinal Fluid Diversion for Adult-Onset Syringomyelia? A Systematic Review ofthe Literature, World Neurosurgery (2014), doi: 10.1016/j.wneu.2014.06.044.
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Arachnolysis or Cerebrospinal Fluid Diversion for Adult-Onset Syringomyelia? A Systematic
Review of the Literature
Running title: Arachnolysis or CSF Diversion for Syringomyelia ?
George M. Ghobrial MD,1 Richard T Dalyai MD,
1 Mitchell G. Maltenfort PhD,
2 Srinivas K. Prasad MD,
1
James S Harrop MD, 1
Ashwini D. Sharan MD1,3
1-Department of Neurological Surgery
Thomas Jefferson University Hospital
909 Walnut St., 3rd
floor
Philadelphia, PA 19107
2- Department of Orthopedic Surgery
Thomas Jefferson University Hospital
Philadelphia, PA 19107
3- Corresponding Author:
Ashwini D. Sharan MD
Associate Professor of Neurological Surgery
Thomas Jefferson University Hospital
Cell 215-955-7003
Fax 215-503-7373
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Abstract
OBJECTIVES: To identify surgical practice patterns in the literature for non-pediatric
syringomyelia by systematic review and to determine: (1) What is the best clinical practice of
CSF diversion that will maximize clinical improvement and/or the lowest recurrence rate? (2)
Does arachnolysis, rather than CSF diversion, lead to prolonged times to clinical recurrence?
Methods: A PubMed (1966 to Aug 2012), Cochrane Register of Controlled Trials, CINAHL,
SCOPUS, and Cochrane Database of Systematic Reviews, database search was conducted for
pertinent articles by the authors with postinfectious, posttraumatic, or idiopathic syringomyelia.
RESULTS: An advanced PUBMED search in August 2012 yielded 1350 studies, finding
twelve studies meeting CEBM criteria for level 4 evidence as a case series, with a total of 410
patients (mean age 39 years). Data on 486 surgeries were collected. Mean follow-up data was
available for ten studies, with a mean follow-up time of 62 months. On regression analysis,
increased age had a significant correlation with a higher likelihood of having clinically
significant recurrence on mean follow-up (P<0.05). The use of arachnolysis in surgery was
associated with a longer duration until clinically symptomatic recurrence (P=0.02). Data on
mortality was unavailable. The mean number of surgeries per patient across all studies was 1.20
(range 0.95-2.00).
CONCLUSION: With post-infectious and post-traumatic etiologies, arachnolysis was the only
surgical treatment to have a statistically significant effect on lowering recurrence rates. More
prospective, randomized, controlled studies are required to reach a clear consensus.
Key Words: Syrinx, Syringopleural Shunt, syringomyelia, syringosubarachnoid, arachnolysis
Short title: Surgical Management of Syringomyelia: A Systematic Review
Introduction
Syringomyelia is described as a pathologic condition of the spinal cord where there is a cystic
dilatation and expansion of the spinal cord resulting from abnormal cerebrospinal flow
dynamics. Its incidence is difficult to determine and varies based on the underlying etiology and
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population studied. The most common etiologies are posttraumatic, postinfectious, hindbrain
hernation-related (Chiari), and occasionally due to craniovertebral junction lesions. One
estimate of the risk of syringomyelia after traumatic spinal cord injury is 28%.[41] Physiologic
studies point to abnormal CSF pulse pressure and velocity as well as flow into the spinal cord via
perivascular spaces as a mechanism for symptomatic growth of a syrinx.[24, 42] Additional
work points to arachnoidopathy, leading to aberrant CSF flow, ultimately resulting in
extramedullary arachnoid cysts that develop pressure with time.[11, 29, 54]
Treatment guidelines are varied, and large case series are limited. In the case of arachnoid
adhesions and recurrent cystic compression, the treatment is often arachnolysis, with or without
cerebrospinal fluid (CSF) diversion. Kaplain-Maier curve data from prior studies show clinically
sympstomatic recurrence rates after treatment of 34 and 40% at 5 and 10 years, respectively.[36]
Given the prevalence of patients with any variety of specific syringe- pleural,peritoneal, or
subarachnoid shunts is so low, there are no set guidelines for its use. Surgical decisions are thus
guided by institutional experience and previous training bias. One prior systematic review of the
literature explores the indications of surgery, recommending against early decompression with
the specific goal to prevent post-traumatic syringomyelia, as well as surgery for the goal of
treating pain and other sensory findings without motor deficits in the setting of an expanding
syrinx.[8] Pertinent clinical questions not previously answered in a systematic review include:
(1) What is the best clinical practice or implementation of cerebrospinal fluid (CSF) diversion
that will lead to the highest likelihood of clinical improvement and/or lowest recurrence rate? (2)
Does primary arachnolysis, rather than CSF diversion, lead to prolonged times to clinical
recurrence? In the case of Chiari Malformation, the cystic compression, and the underlying
etiology is more pathologic than arachnoiditis. This disease entity has established treatments that
differ greatly than posttraumatic and postinfectious arachnoiditis, resulting in syrinx formation.
Since treatment of the underlying Chiari is considered the definitive treatment for syringomyelia,
this systematic review does not aim to include Chiari or Chiari-related etiologies.
Methods
A PubMed (1966 to Aug 2012), Cochrane Register of Controlled Trials (1950 to August
2012), CINAHL (1981 to August 2012), SCOPUS (1960 to August 2012), Cochrane Database of
Systematic Reviews (2005 to August 2012) database search was conducted for articles pertaining
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to postinfectious, posttraumatic, or idiopathic adult syringomyelia. Keywords and MeSH terms
utilized were consistent through all search engines and included ‘Syrinx’, ‘Syringopleural shunt’,
‘syringoperitoneal shunt’, ‘syringosubarachnoid shunt’, ‘syringomyelia’, ‘hydromyelia’,
‘arachnolysis’, ‘cystopleural’, ‘cystoperitoneal’, and ‘shunting’. Papers were limited to English,
human subjects, and those published or published before print. Relevant papers were then
carefully selected by two authors (G.G., R.D.) and then applicable articles of interest were
reviewed from the respective bibliographies, where all articles were reviewed for inclusion by
the remaining authors.
Study Selection
Comparative case series, comparative cohort studies, clinical trials, meta-analyses, and
systematic reviews were eligible for inclusion. Those abstracts excluded were noncomparative
and descriptive studies, technical notes, and case reports. Articles included must have had to
analyze one or more variables described in the pertinent clinical questions, specifically, type of
intervention for symptomatic syringomyelia or arachnoid adhesion, method of surgical
intervention, arachnolysis, shunting, or both. Exclusion criteria included articles that were
unrelated to the interventions or outcomes of interest, as well as pediatric syringomyelia
including those related to pediatric hindbrain herniation/Chiari malformations. The primary
outcome of interest was time to recurrence of neurological complaint or deficit. Secondary
outcomes of interest were factors associated with decreased recurrence of symptomatic
syringomyelia as well as complication rate. Studies that met these criteria were included in the
final analysis (Table 3). Meta-analyses that met criteria were included for comparison to results.
This reference was reviewed in detail to confirm that no individual studies were duplicated in the
final analysis.
Data Extraction and Analysis
Grading of articles on quality of evidence was done via the Oxford Center for Evidence-
Based Medicine (CEBM) ranking criteria (table 1).[26] Data for the number of patients,
presenting complaint, type of neurosurgical intervention, post-operative functional outcome, rate
of recurrence of symptoms, overall complication rate, hospital length of stay (LOS), and average
interval of follow-up was recorded. Recurrence rate was defined by the percentage of patients in
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each study with recurrent symptoms . While the time to recurrence was defined by each
individual study was evaluated, most commonly this was documented as the time to recurrence
of initial presenting neurologic complaints. Data extracted was confirmed by two authors (G.G.
and R.D.) on an independent basis. A proprietary software package was utilized for statistical
analysis (‘R’ v. 2.15.1 by the R Foundation for Statistical Computing, Vienna Austria). A
generalized linear model with quasibinomial family to account for variation beyond that
expected in ordinary binomial (logistic) regression was utilized. The extra variation was
expected because of the dissimilarity between studies.
RESULTS
A PUBMED search in August 2012 yielded 1350 studies, finding twelve studies
meeting CEBM criteria for level 4 evidence as a case series, with a total of 410 patients (mean
age 39 years) (Figure 1). There were no previously published randomized controlled trials
pertaining to surgical management of syringomyelia. Data on 486 surgeries were collected.
Mean follow-up data was available for ten studies, with a mean follow-up time of 62 months
(Table 2). Data on etiology was tabulated for 395(96%) patients (table 2). The most common
etiology reported was was posttraumatic (n= 211, 51%), followed by hindbrain herniation (Chiari
malformation, n = 112, 27%). Seven studies tracked the mean duration of symptoms prior to the
initial surgical intervention across all etiologies, which was 67 months. Eight studies tabulated
data on post-operative syrinx size on MRI, finding 76% in reduction of the syrinx after surgery
(Table 3). Preoperative and post-operative functional outcomes were not available, for most
studies.
On regression analysis, increased age had a significant correlation with a higher
likelihood of clinically significant recurrence on mean follow-up (P < 0.05). The presence of
arachnolysis in surgery was associated with a longer duration until clinically symptomatic
recurrence (P=0.02). Younger patients (P = 0.04) and earlier follow-up appointment (P = 0.05)
were more likely seen with clinically stable disease (Table 4). Duration of symptoms prior to
surgery, and CSF diversion methods did not significantly impact clinical recurrence or functional
outcome. Data on complication rate was largely unavailable and without a standard definition.
The mean number of surgeries per patient across all studies was 1.20 (range 0.95-2.00). The
mean number of surgeries per patient per two years ranged from 0.2 to 1.37 (Table 3).
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DISCUSSION
Syringomyelia is a rare entity with a limited patient population reported in the literature. The
etiology of syringomyelia and arachnoid cyst formation is multifactorial, as evidenced by the
volume of literature regarding pathophysiology of intramedullary CSF cyst formation.[4, 5, 12,
17, 16, 18, 21-23] Spinal cord trauma resulting in an ischemic insult to the cord has been
thought to result in cystic degeneration of the spinal cord. This cystic formation then results in a
space for abnormal CSF flow, and finally pathologically high pressure causing dilation of the
cyst, resulting in spinal cord damage and neurologic symptoms.[6, 9, 20, 34, 32, 46, 47] Further
expansion of the cyst and dissection of a CSF cavity into the spinal cord parenchyma has been
proposed by Bernard Williams, one of the earliest investigators into the underlying mechanisms
of this disease.[55, 56] Often, arachnopathies, or abnormal adherences in the arachnoid tissue
results in abnormal CSF flow dynamics. This abnormal flow seen in the nontraumatic
syringomyelia patient results in CSF pulsations, either dissecting into the spinal cord itself, or
forming cystic, extramedullary cavities that fill and build pressure in a ‘one-way valve’ type
mechanism.[36] Further work regarding the anatomy of the leptomeninges has found a higher
incidence of septations in the posterior subarachnoid space, particularly in the upper thoracic
spinal cord. These septations are not found in the anterior subarachnoid space and can contribute
the formation of adhesions and arachnoid cysts.[36]
The vast majority of literature is presented as retrospective case series detailing the operative
experience at large, tertiary care centers. Obstacles to interpreting previous data has been the
great variation seen in individual surgical management prior to retrospective review. Indeed, no
two patients are alike in regards to surgical history for management of syringomyelia. This
complex clinical course makes interpretation of individual therapies difficult. Intuitively,
studies with a longer mean follow-up had a higher incidence of clinical recurrence of symptoms
and should be taken under consideration when comparing the individual surgical treatments
(Table 2). The mean number of surgeries per patient per two years was calculated to account for
this, but was not statistically significant.
Syringopleural Shunting
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The first syringopleural shunt was performed in 1892, with postoperative neurologic
improvement.[1] This procedure has become a popular procedure due to the anatomic proximity
of the pleural space to the cervicothoracic syrinx of interest, as well as the negative pressure of
the pleural space. Williams and colleagues[58] advocated the initial use of syringopleural
shunting over syringoperitoneal shunting due to the convenient anatomical location, with no
need for repositioning introperatively. More recent use of the syringopleural shunt by Isik et al.
has found good results in the short term.[28] Cacciola et al[10] found on 1 year follow-up with
sixteen patients that had underwent syringopleural Shunts for syringomyelia an improvement in
their modified Japanese Orthopedic Association Score. Long term outcomes are mixed, citing a
higher failure rate with recurrent symptoms.[44, 45, 60] Isik et al[28] in a retrospective review
halted neurologic progression with syringopleural shunting in nine patients, with three patients
requiring craniovertebral decompression (CVD) as a second procedure. More pronounced
improvement was noted with larger syrinxes with an average time for decompression from six to
ten months. Bindal[7] and Vernet reported good long term results with limited morbidity for
pediatric populations with Chiari as an underlying etiology of syringomyelia.[52] Still, other
data reports a high likelihood of repeat surgery within one year.[35, 44]
Many of these patients had CVD as a primary or secondary procedure, and should be taken
into consideration when evaluating the efficacy. For this reason, we have excluded hindbrain
hernation and patients with craniovertebral decompression from the systematic review, given the
extensive differences between pediatric populations compared to adults with post-traumatic and
post-infectious etiologies. Also, there is already plenty of retrospective data that shows greater
clinical improvement when CVD precedes CSF shunting.[27, 30, 43] The addition of this major
surgery makes a comparison of other treatments of CSF diversion not feasible.
Syringosubarachnoid Shunting
Syringosubarachnoid shunting carries a low morbidity[2, 15, 27, 30, 39, 49, 48, 50, 52, 61]
and is the least invasive of the CSF shunting procedures. Vaquero et al[51] in a retrospective
review of 9 patients halted progression of neurologic deficits utilizing syringosubarachnoid
shunts for syringomyelia. Tator et al[49] demonstrated favorable results on follow-up with
syringosubarachnoid shunting in 72.5% of patients. Literature regarding syringosubarachnoid
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shunting is limited to retrospective case series, and no comparative studies are available to
demonstrate its relative efficacity.
One concern raised with creating a channel from the syrinx to the subarachnoid space, is flow
reversal into the syrinx, particularly in the case of a tight posterior fossa, where valsalva
maneuvers encourage CSF flow gradients into the syrinx.[57] Ultimately, this procedure
remains available to the clinician, when shunting to the pleural or peritoneal space is not feasible
(given a prior history of thoracic or abdominal surgery, pleurodesis, or intraabdominal surgeries
raising concerns about scarring). Also, as seen in our analysis, the outcomes of previous series
did not differ greatly for syringosubarachnoid shunting (table 3). The patients most definitely
would be experience less post-operative pain, because there is no need for a second incision with
this procedure.
Lumboperitoneal Shunting
Limited experience in the literature is reported for the use of lumboperitoneal shunts for
syringomyelia. It’s benefit is the drainage of CSF from the lumbar cisterns without the risk of
neurologic deterioration from myelotomy. This is weighted against the lack of direct
decompression and lysis of adhesions at the level of pathology. Oluigabo[38] treated nineteen
patients, with a mean follow-up of 25 months, finding neurologic improvement in five patients,
and halting disease progression in the majority.
Arachnolysis
Many advocate for the initial use arachnolysis without CSF shunting, citing excellent
results.[3, 33, 40, 53] Aghakhani et al[3] in a retrospective comparison of arachnolysis versus
syringopleural shunting as the primary treatment for symptomatic syringomyelia, found superior
results in the arachnolysis group, with regard to rates of reoperation, time to deterioration, and
clinical recurrence.
Largely, patients that had underwent arachnolysis during their clinical course, regardless of
the etiology of the syringomyelia, had a significantly longer symptom-free duration before
clinical recurrence. Klekamp et al[35] reviewed 131 patients with a history of post-traumatic
syringomyelia, where 61 patients underwent surgical intervention. Interestingly, the onset of
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symptoms due to syringomyelia, after SCI ranged from one month to 46 years.[35] The most
common symptom encountered was worsening motor function. Excellent results were obtained
with arachnolysis, untethering, and duraplasty alone, whereas CSF shunting was reserved as a
secondary measure. This surgical measure addresses the underlying etiology of disrupted CSF
flow dynamics, dilation of the arachnoid and cord compression.[33] For the subgroup of patients
in the posttraumatic syringomyelia analysis by Klekamp et al[35], those with clinically stable
neurological function had the same progression-free survival at 10 years regardless of surgery or
not. Those with neurologic worsening had a better functional outcome with surgery (79%
progression-free survival at 5 yrs). Also, for those patients not responding to arachnolysis and
shunting, patients with complete injuries were offered cordectomy to halt progression once and
for all, which this did work for four patients in their series, as well as previous published.[14, 15,
19, 31, 37, 59]
One further consideration is the surgical extent of arachnolysis and decompression. This
variation in surgical technique may be crucial to successful outcome. Surgical technique in this
nonstandard procedure varies greatly. Klekamp and Edgar[13, 35] advocate the use of
duraplasty to increase the size of the arachnoid space to limit tethering, as well as meticulously
limit bleeding into the arachnoid space. Further work might include in the future post-operative
MR imaging to show the extent of decompression of the subarachnoid space after untethering.
This can be then shown to correlate with the success of arachnoidopathy. Additionally, interest
in the role of arachnolysis as a primary treatment has been promising. Hayashi et al[25]
achieved a mean reduction of the syringomyelia from 9 to 5 vertebral levels when detethering of
the adhesions and placement of up to two silicone tubes to divert CSF rostral and caudal to the
site of arachnolysis was performed.
Comparison of Surgical Procedures
Multivariate regression analysis demonstrated that decreased age, arachnolysis, and
decreased time to follow-up were the only significant factors that lowered recurrence rates (table
4). CSF diversion did not have a significant impact on outcome. Complication rates are
obscured by the lack in uniformity of surgical procedures, even among individual series
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themselves. Many patients had multiple surgeries, and follow-up times varied greatly. Likely,
the lack of uniformity in follow-up time is what has contributed most to the variations in success
rates.[34] Unfortunately, regardless of surgical intervention, patients with symptomatic
syringomyelia will undergo multiple procedures in their lifetime. In our statistical analysis,
arachnolysis was the only procedure to have a statistically significant impact on decreasing
symptomatic recurrence. After the failure of this therapy, an argument can be made for CSF
flow diversion via any of the aforementioned shunting methods. More evidence has been
published recently in support for arachnolysis, duroplasty, and/or subarachnoid-subarachnoid
shunting, without fenestration of the syrinx at this time. Good outcomes were reported in the
majority of these patients.[16, 25, 35, 36] Bonfield and colleagues[8] in the only prior systematic
review are able to draw few conclusions from the literature based on the lack of randomized
controlled evidence. They make weak recommendations in favor of duroplasty with
arachnodolysis as the primary treatment over shunting of the syrinx, in the setting of acute motor
weakness, but not in the case of acute sensory or pain syndromes.[8] Despite the lack of level I
evidence to support the use of any primary therapy over another, equivalent outcomes have been
demonstrated in methods of CSF flow restoration without syringotomy.
The limitations of making treatment decisions based off of retrospective data alone are
significant. This systematic review highlights the need for a syringomyelia registry, where a
prospective database for this relatively uncommon disease can be used to follow outcomes.
Lastly, it must be emphasized that there is an inherent difficulty encountered with making
management recommendations for syringomyelia, as well as other uncommon surgical conditions. The
chief limitation is that many tertiary care spine centers are treating diseases based off of their own
recommendations, a difficulty which a can be fixed with multi-center, randomized, controlled trials.
Conclusion
Syringomyelia is a debilitating disease where there exists no clearly superior method of
surgical management. Among retrospective reviews of adults with symptomatic syringomyelia
with predominantly post-infectious and post-traumatic etiologies, arachnolysis, rather than CSF
diversion, was the only initial surgical treatment to have a statistically significant affect on
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lowering recurrence rates. However, recommendations are limited by both the lack of
prospective studies, and long-term surveillance, both of which are vital to detecting the
frequency of rescarring and need for further surgery. Prospective and randomized, controlled
studies however, are lacking with uniformity in treatment and follow-up to make a clear
consensus as to what is the surgical management of choice for syringomyelia.
Acknowledgements: None
Conflicts of Interest and Source Funding:
There were no conflicts of interest in the manuscript, including financial, consultant, institutional
and other relationships that might lead to bias or a conflict of interest. There were no sources of
funding available for this manuscript.
Abbreviations
CSF – cerebrospinal fluid, CEBM- Centers for evidence Based medicine, LOS- length of stay,
CVD- craniovertebral decompression.
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Figure Legend
Figure 1: Flow diagram demonstrating relevant articles reviewed and exclusion algorithm.
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Table 1- Centers for Evidence Based Medicine Criteria
Level of Evidence Study Methodology
Ia Systematic Review of
Randomized Controlled
Trials
Ib Randomized Controlled Trial
II Systematic Review of Cohort
Studies
III Case-Control Study
IV Case Series
V Expert Opinion
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Citation Indications for
treatment
primary treatment N Surgeries,
n
mean
follow-
up (m)
Reoperation
tracked?
duration
of
symptoms
prior to
surgery
(m)
decreased
syrinx by
MRI? ( % )
clinical
recurrence
at mean
f/u, %
Aghakani et
al.45
neurological
deficit
arachnoidolysis vs.
CSF diversion
34 42 86 yes 133 86 73
Cacciola et
al.26
neurological
deficit
Syringopleural
shunting
20 20 37.5 yes n/a 89.4 0
Isik et al.25
neurological
deficit
Syringopleural
shunting
44 48 109 yes 24 98 20
Klekamp et
al.32
neurological
deficit
Arachnoidolysis,
duraplasty
61 71 51 yes 56 61 58
Oluigobo et
al.43
neurological
deficit
lumboperitoneal
shunting
19 19 25 no n/a 10.5 33
Padovani et
al.41
neurological
deficit
syringosubarachnoid
shunting
29 32 60 no 72 100 10
Sgouros et
al.28
neurological
deficit
syringopleural and
syringosubarachnoid
shunting
73 73 120 yes n/a n/a 50
Tator et al.
(1982)40
neurological
deficit
syringosubarachnoid
shunting
20 40 60 no 6 n/a 25
Tator et al.
(1988)39
neurological
deficit
syringosubarachnoid
shunt for
syringomyelia
40 38 55.2 yes 82 n/a 10
Ushewokunze
et al.42
neurological
deficit
Arachnoidolysis 40 67 64 yes 72 64 24.9
Vaquero et
al.43
neurological
deficit
syringosubarachnoid
shunting
9 9 17.5 yes 91 100 0
Williams et
al.24
neurological
deficit
syringopleural
shunting
21 27 n/a no n/a n/a 19
Table 2. Clinical course and outcomes of syringomyelia series
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Variables Prolonging Clinical Recurrence
OR 95%
L
95%
H
p-
value
Arachnoidolysis 7.66
5
2.95
6
19.87
9
0.024
7
decreased age 1.14
8
1.06
1
1.242 0.041
Duration of symptoms prior to surgery 0.99
7
0.98
8
1.011 0.967
Decreased duration prior to follow-up 1.03
6
1.01
3
1.06 0.050
2
Table 3. Factors prolonging Clinical Recurrence
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Etiology
Citation Methodol
ogy
N Mean
treatment
age
Surgical
interven
tion
hindbrain
herniation
posttrau
matic
infectious craniovert
ebral
junction
lesion
idiopathic
Aghakani
et al.51
(2010)
Retrospec
tive
34 40 arachnoi
dolysis
vs. CSF
diversio
n
0 19 0 0 0
Cacciola
et
al.26
(2009)
Retrospec
tive
20 51.3 Syringop
leural
shunting
6 8 2 4 0
Isik et
al.6(2012)
Retrospec
tive
44 33.5 Syringop
leural
shunting
32 12 0 0 0
Klekamp
et
al.22
(2002)
Prospectiv
e
61 45 Arachnoi
dolysis,
duraplas
ty
0 61 0 0 0
Oluigobo
et
al.50
(2010)
Retrospec
tive
19 48 lumbope
ritoneal
shunting
5 1 5 2 6
Padovani
et
al.46
(1989)
Retrospec
tive
29 33 syringos
ubarach
noid
shunting
22 4 3 0 0
Sgouros et
al34
(1995)
Retrospec
tive
73 38 syringop
leural
and
syringos
ubarach
noid
shunting
27 34 1 11 0
Tator et
al.
(1982)45
Retrospec
tive
20 44 syringos
ubarach
noid
shunting
0 4 1 0 15
Tator et
al.
(1988)44
Retrospec
tive
40 44 syringos
ubarach
noid
shunt
for
syringo
myelia
12 11 5 0 12
Ushewoku
nze et
al.47
(2010)
Retrospec
tive
40 32 Arachnoi
dolysis
0 40 0 0 0
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Vaquero
et
al.48
(1987)
Retrospec
tive
9 28 syringos
ubarach
noid
shunting
0 9 0 0 0
Williams
et
al.29
(1987)
Retrospec
tive
21 33 syringop
leural
shunting
8 8 2 2 1
Table 1. Syringomyelia: characteristics of the literature
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CSF – cerebrospinal fluid
CEBM – Centers for evidence based medicine
LOS- length of stay,
CVD- craniovertebral decompression.