Arnold chiari

When Is Duraplasty Required in the Surgical Treatment of Chiari Malformation Type I
Based on Tonsillar Descending Grading Scale?
Adem Yilmaz1
, Ayhan Kanat2
, Ahmet Murat Musluman1
, I˙brahim Çolak1
, Yuksel Terzi3
,
Selim Kayacı4
, Yunus Aydin1
INTRODUCTION
For surgical treatment of Chiari malforma-
tion type I (CM-I), there is no consensus
among surgeons about which method is
preferred. More recently, many surgeons
have advocated posterior fossa decompres-
sion (PFD) without duraplasty (7, 21, 30).
Other surgeons prefer to perform bone de-
compression of the posterior fossa and du-
raplasty (12, 17, 26). PFD with duraplasty is
associated with a lower risk of reoperation
than PFD without duraplasty but a greater
risk for cerebrospinal fluid (CSF)–related
complications. We hypothesized that extra-
dural PFD with or without duraplasty may
be better tolerated by patients than intra-
dural procedures. Duraplasty itself with PFD
surgery may decrease postoperative syrinx
size, improve Japanese Orthopaedic Associa-
tion (JOA) scores (4), and improve recovery
rate. To evaluate our hypothesis, we retro-
spectively studied 82 consecutive patients un-
dergoing PFD with or without duraplasty and
compared the outcomes of patients. To our
knowledge, there has been no published re-
port on the effect of duraplasty based cerebel-
lartonsillardescent(CTD)gradinginthesur-
gical treatment of CM-I. The main aim of this
study was to assess the effectiveness of dura-
plasty based on CTD grading scale in symp-
tomatic CM-I.
METHODS
Patients
After approval from the our clinic review
board, the senior author’s (Y.A.) database
of all 82 consecutive patients who had CM-I
with or without syringomyelia over a 10-
year period (1998–2009) was reviewed. All
patientswereolderthan18yearsandunder-
went the PFD procedure at our institution.
CM-I cases were diagnosed with the aid of
magnetic resonance imaging (MRI). The
definition of CM-I in this study was that the
cerebellar tonsil descended more than 5
mm below the foramen magnum. The pre-
operative stage of CTD was determined on
MRIbasedonthefollowingthreeclassifica-
tions: grade 1, the tonsil descended more
than 5 mm below the foramen magnum but
did not reach the C1 arch; grade 2, the tonsil
reached the C1 arch; and Grade 3, the tonsil
descended over the C1 arch (Figure 1). For
Ⅲ OBJECTIVE: To evaluate the effect of duraplasty based on cerebellar tonsillar
descent (CTD) grade in the surgical treatment of Chiari malformation type I
(CM-I).
Ⅲ METHODS: Medical records and magnetic resonance imaging (MRI) scans of
82 patients with surgical correction of CM-I performed at the authors’ clinic from
1998–2009 were reviewed. The preoperative CTD grading scale was obtained.
Patients were divided two groups: duraplasty group (group 1) and nonduraplasty
group (group 2). The preoperative and postoperative size of the syringomyelia
cavity, Japanese Orthopaedic Association (JOA) scores, recovery rate, and
postoperative complications were determined.
Ⅲ RESULTS: There was 58 patients in group 1, who underwent combined
foramen magnum decompression, C1 (and C2 if necessary) laminectomy, and
duraplasty; the 24 patients in group 2 underwent posterior fossa decompression
(PFD) alone with no dural opening performed. There were no statistically
significant differences between preoperative and postoperative size of the
syringomyelia cavity and JOA scores of duraplasty (group 1) and nonduraplasty
(group 2) groups in CTD grades 1 and 2; in CTD grade 3, the decrease in syrinx
cavity and clinical improvement were statistically better in group 1 compared
with group 2 (P < 0.05). Complications in group 1 were statistically significantly
increased compared with group 2 (P < 0.05).
Ⅲ CONCLUSIONS: This study shows that PFD and duraplasty for the treatment of
CTD grade 3 Chiari malformation may lead to a more reliable reduction in the
volume of concomitant syringomyelia and JOA scores. In CTD grade 1 and 2
patients, PFD without duraplasty may be performed.
Key words
Ⅲ Cerebellar tonsillar descent grading
Ⅲ Chiari malformation type I
Ⅲ Posterior fossa decompression duraplasty
Abbreviations and Acronyms
CCJ: Craniocervical junction
CM-I: Chiari malformation type I
CSF: Cerebrospinal fluid
CTD: Cerebellar tonsillar descent
JOA: Japanese Orthopaedic Association
MRI: Magnetic resonance imaging
PFD: Posterior fossa decompression
From the 1
Department of Neurosurgery, Sisli
Research and Education Hospital, Istanbul;
2
Department of Neurosurgery, Rize University Medical School,
Rize; 3
Department of Statistics, University of Ondokuz Mayis
Faculty of Science and Arts, Samsun; and 4
Department of
Neurosurgery, Sar Hospital, Rize, Turkey
To whom correspondence should be addressed:
Adem Yilmaz, M.D. [E-mail:ademyilmaz70@yahoo.com]
Citation: World Neurosurg. (2011) 75, 2:307-313.
DOI: 10.1016/j.wneu.2010.09.005
Journal homepage: www.WORLDNEUROSURGERY.org
Available online: www.sciencedirect.com
1878-8750/$ - see front matter © 2011 Elsevier Inc.
All rights reserved.
PEER-REVIEW REPORTS
WORLD NEUROSURGERY 75 [2]: 307-313, FEBRUARY 2011 www.WORLDNEUROSURGERY.org 307

comparisons among these categories, JOA
scores, recovery rate, decrease in syrinx
size, complications, and reoperation rate
were assessed for each grade (Table 1).
Surgicalindicationswereusuallyheadache
or tussive headache; drop attacks; neck, arm,
orbackpain;swallowingdifficulties;orupper
extremity numbness or tingling. The pres-
ence of a syrinx was also an indication for
surgery when it occurred in the presence of
the aforementioned symptoms.
Surgical Procedure
Allpatientsunderwentosseousdecompres-
sion including PFD and C1 laminectomy
and were grouped according to tonsillar de-
scending grading scale. The degree of ton-
sillar descent was graded in relation to the
superior and inferior borders of the C1 lam-
ina. The specific surgical procedure (non-
duraplasty or duraplasty) was chosen based
on the surgeon’s experience and prefer-
ence.Aftergeneralanesthesiawasadminis-
tered, all surgeries were performed with the
patientinthepronepositionwithrigidhead
fixation. A midline incision extending from
the inion to the upper cervical spine was
used to perform a standard subperiosteal
dissection of muscle from the occipital and
cervical region. Muscle attachments were
preserved at the superior nuchal line and
usually at the C2 lamina. Osseous decom-
pression was achieved with a high-speed air
drill, encompassing the inferior aspect of
the occipital bone with modest superior ex-
tension (approximately 1.5–2.0 cm) and lat-
eral extension to the lateralmost aspect of
the foramen magnum and cervical spinal
canal, and C1 laminectomy (and C2 if nec-
essary) was performed. In the duraplasty
group, after the dura was opened, dural
grafting was performed with cadaveric
dura, bovine pericardium, fascia lata, or au-
tologous pericranium. No sealant was used
to reinforce the dural suture line, and no
forced inspiratory pressure was routinely
used to test the integrity of the dural clo-
sure.Inthenonduraplastygroup,onlybone
removal was performed. Finally, the wound
was meticulously closed with interrupted
sutures, each layer at a time: muscles, fas-
cia, subcutaneous tissue, and skin.
Follow-up
Postoperative clinical improvement was as-
sessed from clinic notes and generally re-
flected subjective reports of improvement
in symptoms evaluated using the JOA scale
and recovery rate. Recovery rate according
to the JOA scale (15), which indicates the
degree of normalization after surgery, was
calculated using the following formula:
Postoperative score Ϫ Preoperative score
Recovery rate ͑%͒ ϭ __________ ϫ 100
18 Ϫ Preoperative score
All patients underwent MRI 3–5 days after
surgery and at least one subsequent MRI ses-
sion at the follow-up consultation, usually
6–12 months later. The presence or absence
ofsyringomyeliaanditslocationandextentin
thecervicalorthethoraciccord(orboth)were
assessed preoperatively and at least 6 months
postoperatively and as needed thereafter. Syr-
inx improvement was defined as any demon-
strable decrease in maximal syrinx diameter,
as seen on MRI at least 6 months postopera-
tively. In practical terms, syrinxes that were
smaller postoperatively showed minimal re-
sidual, indistinguishable from mild dilation
ofthecentralcanal.Inpatientswithpostoper-
ative MRI (Figure 2), the change in the size of
the syrinx cavity was classified as improved
(decreased maximal diameter), unchanged,
or increased.
Outcome Measures
The long-term (average 9 months postopera-
tively) surgery-related result was considered
excellent if symptoms resolved. The result
was considered good if the patient experi-
encedsignificantimprovementbutalsoresid-
ual symptoms. A poor result indicated no
change in symptoms or deterioration. Specif-
ically noted symptoms were assessed at the
time of follow-up examination.
Statistical Evaluation
Statisticalanalysiswasperformedwiththeassis-
tance of computer statistics programs (SPSS
10.0.7;SPSS,Inc.,Chicago,Illinois,USA)byone
oftheauthors(Y.T.).Statisticalanalysiswasper-
formedusingStudentttest,analysisofvariance
test, and univariate and multivariate regression
analysis.AprobabilityvalueϽ0.05wasconsid-
eredstatisticallysignificant.
RESULTS
Meanageofpatientsineachgroupwassim-
ilar at the time of surgery (duraplasty group
38.9 years and nonduraplasty group 31
years). There were 58 patients in group 1,
who underwent combined PFD, C1 (and C2
if necessary) laminectomy, and duraplasty;
the 24 patients in group 2 underwent PFD
without duraplasty. There were 36 men and
46 women.
Group 1 (Duraplasty Group)
Of the 58 patients in group 1, 25 (43.1%)
were in CTD grade 1, 21 (36.2%) were in
CTD grade 2, and 12 (20.7%) were in CTD
grade3.ThemeansoftheJOAscoresbefore
surgeryandatthefinalfollow-upevaluation
Figure 1. (A) Grade 1 tonsillar descent. Tonsil descended to above C1 arch. (B) Grade 2 tonsillar
descent. Tonsil descended to C1 arch level. (C) Grade 3 tonsillar descent. Tonsil descended below
C1 arch.
PEER-REVIEW REPORTS
ADEM YILMAZ ET AL. DURAPLASTY IN SURGICAL TREATMENT OF CHIARI MALFORMATION TYPE I
308 www.SCIENCEDIRECT.com WORLD NEUROSURGERY, DOI:10.1016/j.wneu.2010.09.005

were 14.2 points (range 10–17 points) and
16.01 points (range 8–18 points), and the
mean recovery rate was 56.3%. An improve-
ment in symptoms occurred in 52 (89.6%)
of these patients. Based on CTD grading
scale in group 1, all 25 patients in grade 1,
18 (85.7%) of 21 patients in grade 2, and
9 (75%) of 12 patients in grade 3 showed
clinical improvement. Of these patients, 45
(77.5%) had syringomyelia. Of the patients
who underwent follow-up MRI, 41 (91.1%)
had a decrease in the size of syringomyelia,
and 37 (90.2%) had clinical improvement.
In addition, 10 (83.3%) of 13 patients with-
out syringomyelia experienced clinical re-
covery. The size of the syringomyelia cavity
was decreased in 17 (89.4%) patients in
grade 1, 16 (94.12 %) patients in grade 2,
and 8 (88.8%) patients in grade 3.
Group 2 (Nonduraplasty Group)
Group 2 comprised 24 patients who under-
went PFD and C1 laminectomy without du-
raplasty. There were 11 (45.8%) patients in
CTD grade 1, 8 (33.3%) patients in CTD
grade 2, and 5 (20.9%) patients in CTD
grade3.ThemeansoftheJOAscoresbefore
surgery and at final follow-up evaluation
were 14.8 points (range 9–18 points) and
16.5 points (range 12–18 points), and the
mean recovery rate was 51.9%. An improve-
ment in symptoms occurred in 19 (79.1%)
of these patients. Based on CTD grading
scale, 10 (90.9%) of 11 patients in grade 1, 6
(75%) of 8 patients in grade 2, and 3 (60%)
of 5 patients in grade 3 experienced an im-
provement of symptoms. Of these patients,
19 (79.1%) had syringomyelia. Of the pa-
tients who underwent follow-up MRI, 16
(84.2%) had a decrease in the size of syrin-
gomyelia, and 16 (84.2%) had clinical im-
provement. Three (60%) of five patients
without syringomyelia experienced clinical
recovery.
Procedure-Related Complications
Complicationsoccurredinsevenpatientsin
the duraplasty group (group 1): CSF leak in
three cases, additional focal neurologic def-
icit in two cases, superficial infection in one
case, and meningitis in one case. Two pa-
tients(3.6%)ingroup1underwentreopera-
tion because of open CSF fistulas. In the
nonduraplasty group (group 2), surgical
complicationsincludedasuperficialwound
infection and temporary neurologic deficit
in one patient. Two patients (9.5%) in
group 2 underwent reoperation because of
inadequate decompression (Table 2).
The cavity size of syringomyelia preoper-
atively and postoperatively, JOA scores, re-
covery rate, and complication rate were de-
termined. Two samples Student t test were
performed. There were no statistically sig-
nificant differences between preoperative
andpostoperativecavitysizesofsyringomy-
elia and JOA scores in duraplasty and non-
duraplasty groups in CTD grades 1 and 2; in
CTD grade 3, the decrease in syrinx cavity
and clinical improvement were statistically
better in group 1 compared with group 2 (P
Ͻ 0.05). Complications in group 1 were sta-
tistically significantly increased compared
with group 2 (P Ͻ 0.05).
DISCUSSION
Surgery for CM-I with or without syringo-
myelia aims at (1) restoration of normal CSF
Table 1. Japanese Orthopaedic Association Cervical Spine Myelopathy Functional
Assessment Scale
Score Definition
Motor Dysfunction Score
of Upper Extremities
0 Inability to move hands
1 Inability to eat with a spoon but able to move hands
2 Inability to button shirt but able to eat with a spoon
3 Able to button shirt with great difficulty
4 Able to button shirt with slight difficulty
5 No dysfunction
Motor Dysfunction Score
of Lower Extremities
0 Complete loss of motor and sensory function
1 Sensory preservation without ability to move legs
2 Able to move legs but unable to walk
3 Able to walk on flat floor with a walking aid (ie, cane or crutch)
4 Able to walk up and down stairs with handrail
5 Moderate to significant lack of stability but able to walk up and down
stairs without handrail
6 Mild lack of stability but able to walk with smooth reciprocation unaided
7 No dysfunction
Sensory Dysfunction Score
of Upper Extremities
0 Complete loss of hand sensation
1 Severe sensory loss or pain
2 Mild sensory loss
3 No sensory loss
Sphincter Dysfunction Score
0 Inability to micturate voluntarily
1 Marked difficulty with micturation
2 Mild to moderate difficulty with micturation
3 Normal micturation
Modified from Benzel EC, Lancon J, Kesterson L, Hadden T: Cervical laminectomy and dentate ligament section for cervical
spondylotic myelopathy. J Spinal Disord 4:286-95, 1991.
PEER-REVIEW REPORTS

circulation at the foramen magnum, (2) re-
duction of the syrinx if there is one, and (3)
relief of the compression exerted by the cer-
ebellar tonsils on the brainstem (Figure 3).
The correct way to treat Chiari malforma-
tions is one of the most disputed issues in
neurosurgery (1, 12, 23, 26).
Surgical Procedure
Considerable debate exists about which
surgical options are best for the manage-
ment of CM-I. Patients with herniation
should be deemed candidates for decom-
pression with or without duraplasty. The
aim of this study was to compare the surgi-
cal outcomes of patients with CM-I after
PFD with or without duraplasty based on
CTD grading scale. The outcome of decom-
pression surgery usually is evaluated by
comparing symptoms before and after sur-
gery. In an effort to define the current sur-
gical strategies, members of the American
Association of Neurological Surgeons were
surveyed as to the surgical approach they
used in pediatric patients with CM-I (10).
Only 9% recommended performing decom-
pressive surgery in asymptomatic patients.
For the treatment of symptomatic patients,
various approaches were used: Approxi-
mately 20% recommended osseous decom-
pression only; 30% recommended osseous
decompression with dural grafting; 25% rec-
ommended osseous decompression with
dural grafting and intradural dissection of
adhesions; and 30% recommended osse-
ous decompression with dural grafting, in-
tradural dissection, and tonsillar manipula-
tion and resection (10). Authors of recent
reports in the literature have suggested that
good clinical outcomes can be attained
without more complex and invasive neuro-
surgical procedures (9, 16).
Duraplasty versus Nonduraplasty
Some authors have advocated that craniec-
tomy alone for CM-I may be sufficient (7,
21, 30), whereas others have argued that the
dura must be opened (11, 17, 22). In a review
of patients who underwent PFD with and
without duraplasty, Matsumoto and Symon
(17) noted no difference in the reduction of
hydromyelia; however, regarding the im-
provement in symptoms, patients who did
not undergo duraplasty had a significantly
worse outcome compared with patients
who underwent duraplasty. Some data sug-
gest a more reliable outcome in size reduc-
tion and even disappearance of an existing
syrinx are achieved when duraplasty is per-
formed (12, 21, 26). Munshi et al. (21) de-
scribed 33 patients who presented with
Chiari malformations during a 10-year pe-
riod. Eleven patients underwent PFD with-
out duraplasty (73% had improvement),
and 23 underwent PFD with duraplasty
(87% had improvement). The rate of minor
complications was higher in the latter
group. There seems to be a subset of pa-
tients, however, whose symptoms resolve
and whose hydromyelic cavity decreases
with the removal of bone only (21). In an-
other study performed in pediatric patients,
it was found that PFD with duraplasty is
associated with a lower risk of reoperation
than PFD but a greater risk of CSF-related
complications. There was no significant
difference between the two operative tech-
niqueswithrespecttoclinicalimprovement
or decrease in syringomyelia (7).
McGirt et al. (18) reviewed the records of
256 children who underwent first-time PFD
for CM-I. All patients underwent suboccipital
craniectomy and laminectomy of the atlas.
The hindbrain was examined intraoperatively
on transdural ultrasonography. If the sub-
arachnoid spaces dorsal to the cerebellar ton-
sils and ventral to the medulla were effaced,
and if the tonsils exhibited the characteristic
rostrocaudal,pistonlikepulsation,duraplasty
was performed. Otherwise, the dura mater
was left undisturbed, and the procedure was
concluded. In children with displacement of
the tonsils below the inferior border of the
arch of the atlas, ultrasonography-indicated
osseousdecompressionalonewasassociated
with twice the risk of symptom recurrence as
decompression with duraplasty. In children
with lesser degrees of tonsillar displacement,
duraplastyindicatedbyultrasonographyfind-
ings yielded the same results as achieved with
osseous decompression alone. McGirt et al.
(18) concluded that intraoperative ultra-
sonography can be used to identify cases that
do not require duraplasty among patients
with lesser degrees of tonsillar displacement,
but it cannot be used for this purpose in pa-
tients with more severe involvement.
Durham and Fjeld-Olenec (7) searched
Medline-Ovid, The Cochrane Library, and
the conference proceedings of the Ameri-
can Association of Neurological Surgeons
and the Congress of Neurological Surgeons
(2000–2007) for surgical techniques of
Figure 2. Syrinx regression after decompressive surgery. (A) Preoperative craniocervical MRI. (B)
Postoperative craniocervical MRI.
PEER-REVIEW REPORTS

PFD and PFD with duraplasty in CM-I. In
theirmeta-analysis,theseauthorsevaluated
five retrospective and two prospective co-
hort studies involving 582 patients. Of the
582 patients, 316 were treated with PFD
with duraplasty, and 266 were treated with
PFD alone. Patients undergoing PFD with
duraplasty had a significantly lower reop-
eration rate and a higher rate of CSF-related
complications. There were no significant
differences in clinical improvement or sy-
ringomyelia decrease between PFD with
and without duraplasty (7). Existing evi-
dence supports the rationale of enlarging
the craniocervical CSF spaces, however (2,
20, 22). In the present study, as Durham
and Fjeld-Olenec (7) reported, there were
no statistically significant differences be-
tween preoperative and postoperative cavity
size of syringomyelia and JOA scores of du-
raplasty and nonduraplasty groups in CTD
grade 1 and 2 (P Ͼ 0.05), whereas in CTD
grade 3, decrease in syrinx cavity and clini-
cal improvement were statistically signifi-
cantly better in the duraplasty group com-
pared with nonduraplasty group (P Ͻ 0.05).
Inthisstudy,manipulationofthesubarach-
noid space and tonsil resection were not
performed because of complications. The
complication rate was significantly higher
in the duraplasty group than nonduraplasty
group, however. We recommend using pre-
operative CTD grading from MRI findings,
and duraplasty should be performed in all
CTD grade 3 patients.
Is Duraplasty Associated with Frequent
Cerebrospinal Fluid–Related Morbidity?
In light of the effort to move toward a less
invasiveandpurportedlylessmorbidproce-
dure, there is a current argument for the use
Figure 3. Artist’s drawing of preoperative and postoperative grade 3 Chiari type I. Posterior fossa
decompression with duraplasty led to decreased syrinx cavity.
Table 2. Summary of Clinical Outcomes After Chiari Surgery According to Cerebellar Tonsillar Descent
No.
Patients
No.
Syrinx
No. Patients with
Symptom Improvement
No. Patients with
Hydromyelia Decrease
No. Patients with
ComplicationsYes No Yes No
Posterior Fossa Decompression
C1 Laminectomy, Duraplasty
(Group 1)
58 (70.8%) 45 (77.5%) 52 (89.6%) 6 (10.4%) 41 (91.1%) 4 (8.9%) 7 (12.0%)
Tonsillar descent
Grade 1 25 (43.1%) 19 (42.2%) 25 (100%) 0 17 (89.4%) 2 (10.6%) 1 (neurologic deficit),
1 (superficial infection)
Grade 2 21 (36.2%) 17 (37.7%) 18 (85.7%) 3 (14.3%) 16 (94.1%) 1 (5.9%) 2 (CSF leak),
1 (neurologic deficit),
1 (meningitis)
Grade 3 12 (20.7%) 9 (20.1%) 9 (75%) 3 (25%) 8 (88.9%) 1 (11.1%) 1 (CSF leak)
Posterior Fossa Decompression,
C1 Laminectomy (Group 2)
24 (29.2%) 19 (79.1%) 19 (79.1%) 5 (20.9%) 16 (87.5%) 3 (12.5%) 2 (8.3%)
Tonsillar descent
Grade 1 11 (45.8%) 8 (42.1%) 10 (90.9%) 1 (9.1%) 7 (87.5%) 1 (12.5%) 1 (superficial infection)
Grade 2 8 (33.3%) 7 (36.8%) 6 (85.7%) 1 (14.3%) 7 (100%) 0
Grade 3 5 (20.9%) 4 (21.1%) 3 (60%) 2 (40%) 2 (50%) 2 (50%) 1 (neurologic deficit)
CSF, cerebrospinal fluid.
PEER-REVIEW REPORTS

of dural-sparing surgery based on the as-
sumption that dural opening is associated
with frequent CSF-related morbidity (5, 6,
17). The common opinion for osseous de-
compression without duraplasty is sup-
ported by the purportedly lower morbidity
of this approach. In this study, according to
our practice protocol, we performed in pa-
tients with CM-I with or without syringo-
myelia a standard PFD, including a small
suboccipitalandforamenmagnumcraniec-
tomy, removal of the C-1 arch, and dura-
plasty, or without duraplasty, and water-
tight closure. In both groups, 2 patients
underwent reoperation. The cause was CSF
fistula in group 1 and insufficient decom-
pression in group 2.
Occurrence of Syringomyelia
Syringomyelia occurs in 50%–76% of pa-
tients. Altered CSF circulation at the fora-
men magnum prevents instantaneous pres-
sure equilibration between the intracranial
and spinal subarachnoid space. Presum-
ably, an intermittent vector of force devel-
ops with each Valsalva maneuver, which
can lead to the progressive downward
movement of developing tissue through the
foramen magnum. If the impediment to
CSF equilibration occurs after the tonsils
have formed, the pressure gradient favors
tonsillar herniation and may be responsible
for the initiation of syringomyelia forma-
tion (26, 28, 29). In the present study, 45
(77.5%) of 58 patients in the duraplasty
group and 19 (79.1%) of 24 patients in the
nonduraplasty group had syringomyelia.
The size of the syringomyelia cavity was
decreased in 41 (91.1%) patients in the dura-
plasty group and 16 (87.5%) patients in
nonduraplasty group.
Value of the Present Study
This consecutive series of 82 patients
treated for CM-I constitutes one of the
larger series reported (3, 8, 11, 13, 14, 19, 24,
25, 27). In this study, in CTD grade 3 pa-
tients, PFD and duraplasty seem to be the
essential surgical treatment of this condi-
tion. Overall, the significant and sustained
postoperative improvement shown in these
82 patients suggests a favorable therapeutic
result in itself and when compared with
other results obtained in previously re-
ported studies. Although the data of the
present study reflect our current practice
regimen, there have been no prospective
studies in which one treatment form is di-
rectly compared with another. In addition,
in light of the many theories of pathophys-
iology, broad clinical presentations, and
multitude of surgical interventions with
variable outcomes, it is not surprising that a
single surgical approach does not exist, and
the results of treatment are difficult to as-
sess given the absence of uniform outcome
measures and a randomized controlled trial
in which the different treatments are com-
pared. In most articles in which outcome is
discussed, the authors have reported an
80%–90% rate of good outcome, with ei-
ther resolution of the symptoms or cessa-
tion of progression.
CONCLUSIONS
PFD with duraplasty in CM-I is associated
with a greater risk for CSF-related compli-
cations. As a result, in this study, complica-
tions from surgical intervention were mini-
mal and results were good, although more
complications were observed in the dura-
plasty group (Table 2). In our experience,
PFD with or without duraplasty in symp-
tomatic adult patients with CM-I is success-
ful in most cases with minimal complica-
tions. We believe that the risk of CSF leak
has to be accepted as a downside of the
essential procedure, which is opening the
dura and widening the cisternal space with
a graft.
We recommend tailoring the surgical ap-
proach to treat the dominant clinical prob-
lem. There is little controversy today that the
commondenominatorofalltreatmentstrate-
gies is posterior craniovertebral decompres-
sion with or without duraplasty. Proper
patientselectioniscrucialtopreventunneces-
sary procedures and to maximize outcome,
and we recommend using CTD grading scale
before planning duraplasty, which should be
reserved for patients who are CTD grade 3.
Furtherstudiesareneededtocharacterizebet-
ter the effect of patients’ tonsillar descending
grade on clinical outcome.
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Conflict of interest statement: The authors declare that the
article content was composed in the absence of any
commercial or financial relationships that could be
construed as a potential conflict of interest.
received 17 June 2010; accepted 10 September 2010
Citation: World Neurosurg. (2011) 75, 2:307-313.
DOI: 10.1016/j.wneu.2010.09.005
Journal homepage: www.WORLDNEUROSURGERY.org
Available online: www.sciencedirect.com
1878-8750/$ - see front matter © 2011 Elsevier Inc.
All rights reserved.
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