Surgical Evaluation and Management of Symptomatic Lumbosacral

A REVIEW PAPE R
Surgical Evaluation and Management o f
Symptomatic Lumbosacral Meningeal Cysts
Guy R . Fogel, MD, Paul Y. Cunningham III, MD, and Stephen I . Esses, M D
Abstract
Sacral meningeal cysts are a fairly common finding i n
the workup of sciatica . In most instances, a cyst
causes no symptoms . Occasionally, a symptomati c
sacral cyst may present with chronic low back pai n
(radiculopathy), sensory loss in sacral dermatomes ,
perinea) pain, or bowel or bladder dysfunction . Compared with computed tomography, magnetic resonance imaging shows meningeal cysts more ofte n
and allows better localization of sacral cysts .
In this article, we present clinical guidelines tha t
may be used to distinguish symptomatic cysts fro m
asymptomatic cysts . We conclude that surgica l
treatment of a symptomatic cyst may includ e
laminectomy with fenestration and imbrication of th e
cyst—or percutaneous treatment methods . Surgery
for sacral meningeal cysts can lead to successfu l
improvement of pain and function in activities of dail y
living in more than 80% of cases .
cysts are dural diverticula that are of congenital o r
acquired onset and that may develop a pedicle with a n
ostium that works in an all-valve fashion to collec t
cerebrospinal fluid (CSF) . Normal fluctuations i n
CSF pressure may account for growth of the cyst and
erosion of adjacent bone surfaces .
Type I extradural meningeal cysts are dural diverticula that may arise anywhere along the thecal sac .
Type I sacral cysts often have a pedicle at the caudal
tip that connects to the thecal sac adjacent to dorsa l
nerve roots .
Type II cysts are dilations of the nerve root sleeve .
The dura may have tears, which can be microscopic t o
fairly large . The wall of type II cysts contains nerve roo t
fibers . Bone erosion (eg, canal-widening pedicular erosion, foraminal enlargement, scalloping of vertebral bod ies or sacrum) is usual in type II cysts . Figure 1 shows
types of extradural cysts that may be surgically treated.
Extradural Meningeal Cyst s
acral cysts are a fairly common finding in th e
workup of sciatica . On myelography for investigation of leg and back pain, the incidence o f
sacral cysts is 17% . On magnetic resonance imaging
(MRI) of 500 asymptomatic patients, the incidence i s
4 .6% . ) These cysts are usually considered incidental
findings on MRI investigations, but occasionally the y
may cause sciatica and other symptoms such as bowe l
and bladder problems and perinea) pain . In this article, we describe the clinical presentation, the MRI and
computed tomography (CT) findings, and the surgica l
treatment options for sacral meningeal cysts .
S
Sagittal View
Corona) Vie w
Large pedicle
Large rent at
base of cyst
Types of SRacra! Cysts
In 1988, Nabors and colleagues 2 classified sacral cysts
into 3 types—extradural cysts (type I) ; extradural
cysts with nerve roots included within the cyst ,
including the Tarlov perineural cyst (type II) ; an d
intradural cysts (type III) . Most sacral meningeal
Dr. Fogel is Spine Fellow, Dr . Cunningham is Medical Researc h
Fellow, and Dr. Esses is Professor of Orthopedics and Brodsk y
Chair of Spinal Surgery, Baylor College of Medicine, Houston ,
Texas .
278
Narrow pedicle
SmaPt rent
or pedicl e
Figure 1 . Variation of connection of extradural cyst to the dura .
A narrow pedicle can be ligated if there is no nerve root involvement in the cyst wall of the pedicle . The large and small rents
may be oversewn to seal the cyst from the dura .
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G . R . Fogel et al
TABLE . LITERATURE REVIEW FOR MENINGEAL CYSTS*
Measure
Extradural Type I
Extradural Type II
Intradural Type II I
No . patients
67
20
7
Cyst location
Throughout spine
Lumbosacral
Throughout spin e
Cyst size
2-5 cm
Unknown
Unknow n
Surgery
Laminectomy cyst excision
Cyst wall excision,
Cyst excision
oversewing
'Identified from the 1960-2001 English-language literature . 1 -3,6-23
Type III cysts are intradural and may occur any where along the posterior subarachnoid space . I n
compression, symptomatic type III cysts act as an y
intradural masses may . The Table lists the meningea l
cyst cases found in the literature and classifies the m
by type .
Clinical Presentatio n
Symptomatic sacral cysts may present in various forms .
Typically, a patient complains of low back pain for sev eral years . The patient has minimal neurologic deficits ,
absent deep tendon reflexes, and bowel and bladde r
abnormalities, including constipation, incontinence, o r
recurring urinary tract infections . Usually, the lowe r
extremity sensation is spared . Radicular pain often i s
relieved or disappears when the patient is recumbent ,
and it is aggravated often by the Valsalva maneuver.
Perineal pain may be present in approximately 50% o f
patients . , Sacral meningeal cysts have been associate d
with childbirth, papilledema, sacral fracture, neurofibro matosis, and dysraphism of the caudal spine .
MRI and CT Finding s
MRI is the best single test . Compared with CT, MR I
shows meningeal cysts more often and allows bette r
Figure 2. Sagittal magnetic resonance imaging views of 2 lurn -
bosacral meningeal cysts . The L4-L5 cyst, which extends int o
the left foramina, was causing radicular pain in the left leg .
THE AMERICAN JOURNAL OF ORTHOPEDICS ®
localization of sacral cysts . MRI determine s
whether cysts are filled with fluid and thereb y
excludes solid tumors . When the signal intensity of
the mass is the same as that of the theca] sac, a diagnosis of CSF-containing structure may be confidently made . MRI shows a higher intensity on T z
weighting compared with CSF, probably related t o
increased protein and solute content and absence o f
CSF motion effects . Tsuchiya and colleagues 4 state d
that MRI with myelography may be especially sensitive with postoperative patients because myelographic material may highlight cysts despite th e
bony changes related to surgery or the scallopin g
associated with the cyst itself . Figure 2 show s
meningeal cyst changes in the lumbosacral are a
on MRI .
Routine radiographs of the sacrum and lumbar
spine may show bone erosions, but this result i s
uncommon . CT myelogram is important in deter mining whether a cyst communicates with th e
subarachnoid space . If intrathecal dye does no t
fill the cyst even with some delay, then simpl e
oversewing of the posterior cyst wall is all that i s
required . If the cyst communicates with the subarachnoid space, the pedicle or communicatio n
must be found and ligated to prevent recurrenc e
of the cyst . CT myelogram may show the presence or absence of the free communication of th e
cyst with the spinal subarachnoid space . Delaye d
myelographic images are important and may sho w
an extradural arachnoid cyst that fills slowl y
through a small pedicle connecting the cyst wit h
the thecal sac . Myelography may produce a false negative result if the pedicle of the cyst is to o
narrow to allow entry of intrathecal contras t
material . Another problem is that CT seldo m
shows sacral roots, except S1, because CT is limited to pedicle-to-pedicle scanning in most cases ,
and lumbar CT seldom is ordered below L5-S1 .
CT of the lumbar and sacrum, sacral tomography ,
and epidurography and intraoperative ultrasoun d
may be helpful but remain unproved in any larg e
number of cases .
27 9
Symptomatic Lumbosacral Meningeal Cyst s
Authors' Clinical Guideline s
Clinical guidelines for distinguishing a symptomatic
cyst from an asymptomatic cyst are useful .
First, it is important to rule out any other possible
causes of back and leg pain . It is absolutely necessary not to ascribe complaints of back and leg pain t o
a cyst unless it is reasonably certain that the cyst is
causing the pain . Unfortunately, this is not alway s
possible, and there is not a reliable test for determin ing the clinical relevance of a sacral cyst . It is important to rule out disc herniation, spinal stenosis, an d
spondylolisthesis as causing the patient's pain .
Second, it is important to determine that the cys t
corresponds anatomically to the patient's complaints .
A symptom-producing sacral cyst should cause
sacral radiculopathic symptoms, with radiculopathy
to the buttock and S1 distribution in the leg associated perhaps with bowel or bladder symptoms . The
symptoms should correspond anatomically with th e
cyst ; they should correspond to the same side as th e
cyst and to symptoms affecting the same level o f
nerve roots as the cyst location suggests .
Third, it is useful to see whether pulsatile change s
in CSF pressure increase symptoms . Postura l
changes in CSF pressure may affect complaints .
Radicular pain often is relieved or disappears whe n
the patient is lying down . Increased pain with Valsalva maneuver, cough, or sneeze tends toward a
diagnosis of symptomatic cyst.
Fourth, aspiration of the meningeal cyst may b e
diagnostic of a symptomatic cyst if the symptoms
decrease at least temporarily. This may be done with
CT or fluoroscopic guidance . Aspiration may b e
repeated if initially successful and symptoms recur .
If all 4 criteria are met, then it is reasonable to
suggest that a cyst is symptomatic (Figure 3) .
Evaluation and Treatment Algorithm : Symptomatic Sacral Cys t
Patient with a sacral cyst an d
Chronic low back pai n
Normal lower extremity sensatio n
Absent deep tendon reflexe s
Bowel and bladder abnormalitie s
Consider Diagnose s
Low back sprai n
Osteoarthriti s
Herniated dis c
Spinal stenosi s
Spondylolisthesis
Instabilit y
YES
NOT the cy s
Activity modification
according to severity of
symptoms
Pharmacologic pain contro l
Bracing, modalities, exercise s
Epidural steroid injections
Failure of treatment may
require additional testin g
and treatment consistent with greater level o f
severit y
MRI = magnetic resonance imagin g
CT = computed tomography
Does the cyst cause back and leg pain ?
Rule out non-sacral etiology of pai n
MRI, CT-myelograph y
Electromyograph y
Postural changes : recumbent and Valsalva
YES
NO Pain Relief
Diagostic aspiration relieves pain ?
YES
Repeat aspiratio n
Percutaneous drainage of the cyst
Closure of the cyst with fibrin glu e
Not Successfu l
Surgical treatment—Consideration s
1. Delay of 2-6 months to allow conservative treatmen t
2. Documented failure to respond to treatment ; physical signs an d
radiographic findings of a surgically treatable lesio n
3. Goal is correction of pathological condition, to attai n
functional recovery .
Surgical treatmen t
Decompression laminectomy wit h
Oversewing of cyst neck and partial or total excision of the cys t
Shunting of cerebrospinal fluid from the cyst to the subarachnoid spac e
Figure 3 . Evaluation and treatment algorithm for symptomatic sacral cysts .
280
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G . R . Fogel et a l
Figure 4 . Clinical example of a lumbosacral meningeal cys t
treated surgically . The patient had symptomatic radiculopath y
and no other discernable cause for the leg pain other than th e
cyst . (A) Multiloculated extradural cyst is exposed with a wid e
laminectomy. (B) The base of the cyst is oversewn, and th e
cyst is decompressed with syringe and needle . (C) The base i s
oversewn, and the cyst is collapsed and is not refilling .
Surgical Treatment
Surgical management usually includes extensive bon y
decompression with laminectomy alone or combine d
with either partial resection and oversewing of the cys t
or total cyst excision, which may include sacrifice o f
the involved sacrococcygeal nerve roots . Additional
treatments may include cyst drainage (percutaneou s
aspiration or external drain placement) ; incision ,
drainage, and plication of the cyst wall ; CSF shunting
to the peritoneum or the subarachnoid space ; and closure of the connection between the cyst and the theca l
sac . Type I meningeal cysts are treated by closing th e
pedicle between the cyst and the subarachnoid space .
With type II meningeal cysts, because there is no pedicle to block off, the aim of surgery is to obliterate the
cyst by partial resection and oversewing of the cys t
wall . One must move or protect the nerve roots if the y
are within the wall of the cyst, as in the Tarlov variety
of type II cysts . Type III intradural cysts should be
excised by marsupialization, opening to the surrounding intradural fluid . These cysts are likely to recur .
Recently, cyst drainage, either percutaneous or open ,
has been recommended to decrease symptoms, bu t
cysts treated this way are likely to recur . , In 2001 ,
Morio and colleagues o reported on a case successfull y
managed with cyst subarachnoid shunting (as a variation) . In a preliminary report, Patel and colleagues ?
THE AMERICAN JOURNAI, OF ORTHOPEDICS ®
suggested that fibrin glue may be definitive therapy fo r
sacral meningeal cysts . They extended their method
for sealing dural tears to a CT-guided percutaneou s
procedure for delivering fibrin glue to sacral cysts .
Aseptic arachnoiditis has been a worrisome complication of this percutaneous glue technique .
The most popular treatment may be a combination
of laminectomy, fenestration, and drainage of the cyst ;
blockage repair of the communication with the arachnoid space ; and suture use, perhaps supplemente d
with as-needed placement of fibrin glue to sea l
drainage . Figure 4 (A—C) shows a symptomati c
extradural cyst that was ligated at its base and aspirated . The surgical outcome was good, but the patient
reported having mild radiculopathy-type pain without
weakness intermittently at the 6-month interval ; at th e
time of his report, this pain was improving .
Summary
Sacral meningeal cysts have fascinated spine surgeon s
for decades . In most instances, these cysts are asympto matic . It is necessary to relate complaints of back an d
leg pain to a cyst only when it is reasonably certain tha t
the cyst is causing the pain . Unfortunately, althoug h
MRI and CT can be used to determine the presence of a
meningeal cyst, there is no reliable test for determinin g
the clinical relevance of this cyst . Clinical guidelines are
used to distinguish a symptomatic cyst from an asymptomatic cyst . Treatment options for a symptomati c
sacral meningeal cyst range from aspiration and shunting of the cyst to laminectomy and closure of the communication of the cyst with the thecal sac . Percutaneou s
treatment with fibrin glue is interesting but may have
residual aseptic arachnoiditis as a complication .
281
Symptomatic Lumbosacral Meningeal Cysts
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Editoria l
(continued from page 272)
this is what all patients perceive and dread . It seemed
so long and I never really slept . Each time a medication was due or a nursing procedure needed, th e
nurse would say that she'd be there as soon as sh e
could, but it seemed forever before she returned with
the medication or whatever. There was somethin g
about inefficiency in the pharmacy ; that the nurse s
couldn't just get the ordered medications themselve s
when they are due . I loved the old days when I was a
resident . The nurse and I would round with a car t
with bottles of pills and the charts . If the patien t
wanted or needed something, it was dispensed an d
charted on the spot . Efficient patient care, but "some one's" concern about potential drug abuse by doctor s
and nurses, the possibility of dosage mistakes, and ,
obviously more important, the failure to properly bil l
the patient, have led to the computerized infallible ,
but possibly less efficient system .
Finally, the day came, and, eager to take the firs t
train out of Dodge . I thanked my surgeon, fel t
immensely better than before the surgery, an d
received my discharge diploma . I don't know whether
I learned anything new, but I certainly experienced th e
ebb and flow of emotions that many of my more perceptive patients feel . Certainly the inpatient medical
care has improved over the years . The respirator y
therapist and his instructions and equipment hav e
improved . The OTs and PTs were there and efficiently
rendered their instructions and advice . The preoperative, operative, and recovery room processes are professionally rendered and appropriate, although the
recent well-intended JCAHO requirements result in a
three-stooges comedy routine, with everyone indiscriminately going through the same questions ove r
and over again . Possible nursing shortages and perhaps inpatient pharmacy issues may exist, but perception and reality may not coincide . Nonetheless, I no w
know what my patients can expect and can respon d
with some level of understanding . My fellow surgeons, if you have to have surgery, you will appreciat e
the "education "
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