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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_6009_Библиотеки_им_академика_М_И_Перельмана.pdf
Carotid Dissection
KEY FACTS
TERMINOLOGY
• Internal carotid artery dissection (ICAD): Tear in internal
carotid artery wall that allows blood to enter and
delaminate wall layers
IMAGING
Vascular Disorders
• CTA and MRA are typically 1st step in imaging evaluation
○ T1 MR with fat suppression is best sequence for
hyperintense mural hematomas
• Pathognomonic findings of dissection: Intimal flap or
double lumen (seen in < 10%)
• Aneurysmal dilatation (seen in 30%)
○ Commonly in distal subcranial segment of internal
carotid artery (ICA)
○ Focal pseudoaneurysm is unusual
• ICAD most commonly originates in ICA 2-3 cm distal to
carotid bulb and variably involves distal ICA
○ Stops before petrous ICA
• Angiography
(Left) Axial T1WI MR
illustrates bilateral internal
carotid artery dissections
(ICADs) with isointense mural
thrombus on the right st and
hyperintense mural thrombus
on the left ſt. The residual
lumens are markedly
narrowed. Bilateral ICAD
represents 4-16% of all
dissections. (Right) Axial T1WI
FS MR in the same patient
demonstrates bilateral ICADs.
The fat saturation increases
the conspicuity of the
methemoglobin in the mural
thrombus st.
○ Pathognomonic: Intimal flap + double lumen (true and
false)
○ String sign: Long, tapered, usually eccentric and irregular
stenosis distal to carotid bulb
TOP DIFFERENTIAL DIAGNOSES
• Fibromuscular dysplasia
• Carotid artery fenestration
• Traumatic ICA pseudoaneurysm
• Atheromatous plaque
CLINICAL ISSUES
• Ipsilateral pain in face, jaw, head or neck
• Oculosympathetic palsy (miosis and ptosis, partial Horner
syndrome)
• Ischemic symptoms (cerebral or retinal TIA or stroke)
• Bruit (40%)
• Lower cranial nerve palsies (especially CNX)
• Pulsatile tinnitus
340
(Left) Axial CTA displays soft
tissue density ſt narrowing
the contrast-filled lumen of
both internal carotid arteries
(ICAs) st, compatible with
mural thrombus. Intramural
hematoma usually compresses
the true lumen & causes
enlargement of the external
diameter. (Right) Lateral DSA
exhibits a short segment of
ICA narrowing due to
dissection. Undulating
irregularity of the proximal
ICA may be due to
vasospasm or standing wave
artifact, which is induced by
the angiography catheter & is
related to injection speed.
Fibromuscular Dysplasia
KEY FACTS
Vascular Disorders
TERMINOLOGY
• Fibromuscular dysplasia (FMD)
• Arterial disease of unknown etiology affecting mediumsized and large arteries, most commonly in young to
middle-aged women
IMAGING
• Multifocal ± bilateral cervical carotid or vertebral artery
irregularity on CTA/MRA/DSA; string of beads appearance
• Location
○ Most commonly at C1-C2 levels
○ Carotid artery involved in 30% (bilateral in 65%)
○ Vertebral artery involved in 10%
• Morphological changes of FMD in carotid and vertebral
artery circulations
○ Vessel beading/irregularities: String of beads appearance
○ Arterial stenosis without mural Ca⁺⁺ as opposed to
atherosclerotic vascular disease
○ FMD associations: Dissection, pseudoaneurysm,
intracranial aneurysms
• Best imaging tool
○ CTA or MRA for noninvasive assessment
○ DSA for definitive diagnosis ± endovascular intervention
TOP DIFFERENTIAL DIAGNOSES
• Atherosclerosis
• Arterial dissection
• MRA motion artifact
• Standing waves
DIAGNOSTIC CHECKLIST
• String of beads is classic appearance on CTA/MRA/DSA of
most common subtype (type 1)
• If FMD found in any artery, consider study of cervical and
intracranial arteries for FMD ± associated saccular and
pseudoaneurysms
(Left) Graphic of carotid
bifurcation shows the principal
subtypes of fibromuscular
dysplasia (FMD). Type 1
appears as alternating areas
of constriction and dilatation,
type 2 as tubular stenosis, and
type 3 as focal corrugations ±
diverticulum. (Right) Sagittal
reformatted CTA reveals 2
pseudoaneurysms of the distal
internal carotid artery (ICA)
. There is also a vascular
outpouching of the petrous
segment of the ICA ſt.
Vascular irregularity with
focal narrowing is also
observed st.
(Left) Coronal surfacerendered CTA demonstrates
diffuse bilateral ICA
irregularity ſt with some
areas showing the classic
string of beads appearance.
Note the small
pseudoaneurysm st. (Right)
Lateral angiographic image
displays vertebral artery
irregularity .
Histopathologically, FMD is
heterogeneous with various
degrees of collagen
hyperplasia, internal elastic
lamina rupture, and
disorganization of the tunica
media.
341
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SECTION 10
Complications
Complications Overview 344
Myelography Complications
Vertebroplasty Complications
Failed Back Surgery Syndrome
Epidural Abscess, Postop
Disc Space Infection 350
Meningitis
CSF Leakage Syndrome
Pseudomeningocele
Direct Cord Trauma
Vascular Injury 355
Epidural Hematoma, Spine
Instrumentation Failure
Bone Graft Complications
rhBMP-2 Complications
Heterotopic Bone Formation 360
Recurrent Disc Herniation
Peridural Fibrosis
Arachnoiditis/Adhesions
Arachnoiditis Ossicans
Accelerated Degeneration 365
Postsurgical Deformity
Radiation Myelopathy
346
347
348
349
351
352
353
354
356
357
358
359
361
362
363
364
366
367
Complications Overview
Terminology
Adverse event: Any unexpected or undesirable event
occurring as a direct or indirect result of surgery.
Complication: Disorder related directly or indirectly to
Complications
surgery; will change the expected outcome for the patient.
Medicolegal Issues
The literature evaluating malpractice litigation regarding spine
surgery is limited, but important lessons can be learned from
the available data. Rovit et al. evaluated claims against
neurosurgeons in New York State from 1999 to 2003. Spine
cases constituted 56% of malpractice allegations. It does not
appear that malpractice exposure is limited by limiting the
type of practice one has away from supposedly risky
procedures, such as intracranial disease, complex spine cases,
or emergency cases. Rather, the malpractice claims seem to
be lumped into areas that are common and not complex, such
as "routine" elective spine surgery. In that series, lumbar
claims were more than 2x as common as cervical spine claims.
The costs incurred are high, to say the least. Rovit found that
$50 million was paid out for 280 cases closed against
neurosurgeons during 5 years. Lawyers made $9 million.
Epstein found that malpractice payouts for the cervical spine
vary widely, with plaintiffs' verdicts receiving $4 million on
average, settlements receiving $2.3 million, and defense
verdicts receiving no compensation. This study also found 3
anticipated factors leading to cervical malpractice suits
(negligent surgery, lack of informed consent, and failure to
diagnose/treat). The unanticipated factor that was specific for
cervical spine surgery was failure to brace.
The 1 area where relatively simple imaging can make a
significant impact is wrong level surgery. Thoracic disc
herniation localization is a prime example. This lesion is
generally not apparent on plain films or intraoperative
fluoroscopy, so direct localization is not possible, as may be
with primary bone tumors and metastatic disease.
Preoperative localization may be carried out by multiple
techniques, extending from a skin scratch (indelible markers
being not that indelible to surgical scrubbing) to placement of
radiopaque markers within the soft tissues. This author's
current favorite thoracic localization technique is placement
of small gold beads at the thoracic pedicle/lamina junction at
the appropriate level through an 18-gauge spinal needle using
fluoroscopy. These types of beads were initially utilized for
radiotherapy localization but work very well for general
thoracic level localization. Correlation with CT &/or MR studies
is mandatory. Counting is preferred from C2 down to the level
of interest, given the frequency and confusing nature of
lumbosacral transitional anatomy.
Blind Spots
Imaging of the postoperative spine is tough, both from the
pathology standpoint and the sheer volume of data that
needs to be evaluated, coupled with the bewildering array of
hardware that seems to change daily. The problem is
compounded for the imager by the lack of standards for
approaches/hardware for even the most common of
procedures. Lee et al. found that spine surgeons generally
agree on when to operate in a particular clinical scenario but
fail to agree on what type of procedures to perform. Specific
choices are often related to surgeon familiarity and training
and may not be easily generalized. Metal artifact seems
ubiquitous and further confounds the quality of imaging for
both CT and MR. Metal artifact suppression sequences are
available for MR. While they do help, they are not a panacea,
and degradation of image quality by metal is not going away.
There are no easy shortcuts to evaluate a postoperative CT or
MR if useful information is to be gleaned. Every disc level
needs to be evaluated with step-by-step inspection of the
vertebral bodies, pedicles and posterior elements, and neural
foramen and epidural space. Blind spots can develop, and
having a specific search pattern can help to identify pathology.
For instrumentation, each screw position must be evaluated
and checked to see if it appropriately attaches to the fixation
rod/plate and if the screw is appropriately positioned or if it
has breeched the cortex. Are there screw breaks or rod
fractures? Where are the graft positions? What is spinal
alignment? Is the thecal sac decompressed, and what does the
epidural space look like?
General knowledge of the previous surgical procedures that
the patient has undergone is also essential for identifying
complications. Knowing the surgery and its goals allows the
imager to focus on the most common areas of complication
given the operative approach to the pathology. If you do not
know what a pedicle subtraction osteotomy (PSO) is, then you
will not see the typical appearance of the vertebral body
resection site. You cannot easily recognize what you do not
know, and this extends to something as seemingly apparent
as pedicles. Residents and fellows have stared at a lateral film
of a PSO and not recognized that 1 level is lacking pedicles. Be
particularly vigilant for double or staged procedures, which
have an increased incidence of complications. One study of en
bloc resections showed a 34% complication rate, the majority
of them graded as "major," with a 2% mortality.
Selected References
1. Epstein NE: A review of medicolegal malpractice suits involving cervical
spine: what can we learn or change? J Spinal Disord Tech. 24(1):15-9, 2011
2. Lee JY et al: Surgeons agree to disagree on surgical options for degenerative
conditions of the cervical and lumbar spine. Spine (Phila Pa 1976).
36(3):E203-12, 2011
3. Epstein NE: A medico-legal review of cases involving quadriplegia following
cervical spine surgery: is there an argument for a no-fault compensation
system? Surg Neurol Int. 1:3, 2010
4. Lekovic GP et al: Litigation of missed cervical spine injuries in patients
presenting with blunt traumatic injury. Neurosurgery. 60(3):516-22;
discussion 522-3, 2007
5. Rovit RL et al: Neurosurgical experience with malpractice litigation: an
analysis of closed claims against neurosurgeons in New York State, 1999
through 2003. J Neurosurg. 106(6):1108-14, 2007
6. Fager CA: Malpractice issues in neurological surgery. Surg Neurol. 65(4):41621, 2006
7. Rampersaud YR et al: Intraoperative adverse events and related
postoperative complications in spine surgery: implications for enhancing
patient safety founded on evidence-based protocols. Spine (Phila Pa 1976).
31(13):1503-10, 2006
8. Goodkin R et al: Wrong disc space level surgery: medicolegal implications.
Surg Neurol. 61(4):323-41; discussion 341-2, 2004
9. Malanga GA et al: Segmental anomaly leading to wrong level disc surgery in
cauda equina syndrome. Pain Physician. 7(1):107-10, 2004
10. Dickman CA et al: Reoperation for herniated thoracic discs. J Neurosurg.
91(2 Suppl):157-62, 1999
344
Complications Overview
Spine Surgery Malpractice Allegations
Lumbar Surgery Cervical Surgery
Operation at wrong level Operation at wrong level
Failure of fusion Failure of fusion
Nerve root/cauda equina injury Nerve root/cord injury
Durotomy/CSF leak Infection/abscess
Infection CSF leak
Hardware failure Anterior displacement of graft
Failure to relieve pain Injury to trachea/esophagus
Vascular/visceral injury Recurrent laryngeal nerve palsy
Failure to remove disc completely Failure to relieve pain
Inappropriate indication for operation Inappropriate indication for operation
Failure to remove disc
Infected graft site
Adapted from Rovit RL et al: Neurosurgical experience with malpractice litigation: an analysis of closed claims against neurosurgeons in New York State,
1999 through 2003. J Neurosurg. 106(6):1108-14, 2007.
Cervical Spine Operations and Deficits Leading to Suits
Complications
Operations Deficits
Most to Least
Anterior cervical discectomy/fusion (1 level) Quadriplegia
Posterior laminectomy/fusion Paresis (other)
Anterior cervical discectomy/fusion (2 levels) Pain
Posterior fusion alone C5 root palsy
Anterior cervical fusion (3 or 4 levels) Dysphagia
Vocal cord paralysis
Esophageal perforation
Adapted from Epstein NE: A medio-legal review of cases involving quadriplegia following cervical spine surgery: is there an argument for a no-fault
compensation system? Surg Neurol Int. 1:3, 2010.
Overall Incidence of Adverse Events and Complications
Intraoperative Event Adverse Event Incidence (%) Complication Incidence (%)
Dural tear 8.3 1.6
Instrumentation 3.1 0.3
Massive blood loss 1.4 0.9
Anesthesia/medical 0.6 0.1
Anterior approach 2.1 0.0
Vertebral artery 1.4 0.0
Esophagus/pharynx 2.2 2.2
Sterile field contamination 0.3 0.1
Patient poisoning 0.3 0.0
Surgical instrument failure 0.1 0.0
Change of surgery plan 0.1 0.0
Adapted from Rampersaud YR et al: Intraoperative adverse events and related postoperative complications in spine surgery: implications for enhancing
patient safety founded on evidence-based protocols. Spine (Phila Pa 1976). 31(13):1503-10, 2006.
345
Myelography Complications
KEY FACTS
TERMINOLOGY
• Minor complications
○ Post dural puncture headache (most common)
Complications
○ Incorrect needle position (subdural, epidural)
○ Transient neurologic sequela
○ Contrast reaction (minor)
• Major complications
○ CSF leak
○ Symptomatic spinal subdural or epidural hemorrhage
○ Contrast reaction (major)
○ Cord injury
○ Intracranial hemorrhage
○ Seizure
○ Paralysis
○ Death
• Delayed complications
○ Iatrogenic epidermoid
(Left) Coronal graphic shows
complications of a C1-C2
puncture with cord injury from
the needle as well as
subarachnoid blood. Note the
close proximity to the caudal
loop of the posterior inferior
cerebellar artery ſt. (Right)
Axial CT following an
attempted myelogram shows
focal contrast within cord
substance and a small amount
of epidural gas.
IMAGING
• Myelography technique
○ Monitor initial contrast injection fluoroscopically to
confirm subarachnoid placement
○ Use smaller gauge, atraumatic needles
○ Replacing needle stylet before withdrawing helps to
prevent headache
○ Fluoroscopic guidance for C1-C2 puncture, injection
carefully monitored to avoid cord injection
○ Avoid hyperextension during cervical myelography: Rare
cause of periprocedural cord injury
• Most common complications have no imaging findings
CLINICAL ISSUES
• Dural puncture headache usually begins by 3 days & lasts 35 days
• Nausea, vomiting, hearing loss, tinnitus, vertigo, dizziness,
paresthesias
346
(Left) Axial post myelographic
CT demonstrates contrast
material that is subdural in
location. Note the outlining of
the dentate ligaments by
contrast ſt. The well-defined
outer margin (dura) allows
differentiation from epidural
injection. (Right) Axial
contrast-enhanced T1WI MR
of the brain shows diffuse,
smooth pachymeningeal
thickening and enhancement
in this patient with
intracranial hypotension
following lumbar puncture.
Vertebroplasty Complications
KEY FACTS
Complications
IMAGING
• Extravasation of cement (into spinal canal, neural foramen,
paravertebral spaces, epidural or paravertebral venous
plexus) or pulmonary cement embolism
○ Improper needle placement
○ Inadequate intraprocedural monitoring of
polymethylmethacrylate injection
○ Inadequate polymethylmethacrylate opacification
○ Low cement viscosity or too large of volume injected
○ Underlying neoplasm with deficient cortex
• New vertebral compression fracture adjacent to previously
treated level
• Fat embolism
○ Branching or globular hyperdense material in lung
parenchyma on fluoroscopy, radiography, or CT
• Vertebral osteomyelitis
○ Osseous destruction adjacent to
polymethylmethacrylate
PATHOLOGY
• Adjacent compression fracture
○ 10-15% of treated patients
○ Controversial relationship to vertebroplasty
• Fat embolism
○ Embolism of fatty marrow displaced by
polymethylmethacrylate injection
CLINICAL ISSUES
• Clinical presentation variable depending on complication
type
• Symptomatic complications of vertebroplasty are rare
○ < 1% for osteoporotic compression fractures
○ 2-5% for treatment of osteolytic metastases
DIAGNOSTIC CHECKLIST
• Consider CT to investigate any unexpected peri- or
postprocedural symptomatology
(Left) Lateral radiograph
shows a large volume of
cement extending beyond the
vertebral body into the disc
interspace ſt between 2 other
vertebral bodies that were
also treated, which contain
cement within their confines
. (Right) Lateral radiograph
shows a compression fracture
of a midthoracic vertebral
body treated with
vertebroplasty .
Embolization of cement to the
right lower lobe is seen as
striated opacities projecting in
the retrocardiac space st.
(Left) Sagittal NECT shows
bone cement from a prior 2level vertebroplasty ſt.
Imaging for acute back pain
shows mild, acute compression
fracture of T7 with horizontal
sclerosis due to trabecular
impaction. (Right) Sagittal
T2WI MR shows high signal
surrounding cement several
weeks after vertebroplasty in
a patient on chronic steroid
therapy. Aspiration showed
Staphylococcus aureus
infection. (Courtesy S.
Dunnagan, MD.)
347
Failed Back Surgery Syndrome
KEY FACTS
TERMINOLOGY
• Continued low back pain with or without radicular pain
after lumbar surgery
Complications
IMAGING
• Stenosis: Trefoil appearance of lumbar canal on axial
imaging
• Instability: Deformity increases with motion & time
• Recurrent herniation: Nonenhancing, well-defined mass
arising out of intervertebral disc
• Fibrosis: Infiltration of epidural/perineural fat by enhancing
soft tissue density (intensity)
• Arachnoiditis: Clumping, adhesion of cauda equina nerve
roots
• Improper instrumentation placement
TOP DIFFERENTIAL DIAGNOSES
• Infection
○ Endplate destruction, disc T2 hyperintensity
(Left) Axial graphic of the
lumbar spine shows
postoperative change with
bilateral pedicle screws and
left laminectomy defect. There
is clumping of nerve roots,
reflecting arachnoiditis. The
screws are too anterior and
have breached anterior
vertebral body cortex. (Right)
Axial T1WI MR shows a
laminectomy at L5-S1. There is
peripheral clumping of roots in
the thecal sac due to
arachnoiditis ſt. Note the
droplet of T1 hyperintense
Pantopaque . Posterior
epidural fibrosis is present st
at the laminectomy site.
• Tumor
○ Enhancing soft tissue mass
• Hemorrhage
○ Intermediate T1 signal acute-subacute age
• Pseudoarthrosis
○ Abnormal low T1 signal extending through disc,
posterior elements, and ligaments
PATHOLOGY
• Multiple underlying etiologies for "late" failure
○ Foraminal/central stenosis (20-60%)
○ Pseudoarthrosis/instability (14%)
○ Recurrent herniation (7-12%)
○ Epidural fibrosis (5-25%)
○ Arachnoiditis
DIAGNOSTIC CHECKLIST
• Contrast-enhanced MR 96-100% accurate in detecting
peridural fibrosis vs. recurrent herniation
348
(Left) Sagittal T1WI C+ MR
shows central clumping of
intrathecal roots into a central
rope-like mass, simulating lowlying cord. Note multilevel
laminectomy defect and
degenerative disc space
enhancement, particularly at
L4-5. (Right) Axial NECT shows
bilateral loosened pedicle
screws with prominent lucency
surrounding the mid and distal
aspects ſt. There are also
lucency and bony remodeling
surrounding the junction with
the longitudinal rod .
Nonunion of the graft
spanning L3-5 is shown with
perigraft lucency st.
Epidural Abscess, Postop
KEY FACTS
Complications
TERMINOLOGY
• Spinal epidural abscess
• Extradural spinal infection with abscess formation
IMAGING
• MR
○ T1WI C+: Homogeneously or heterogeneously
enhancing phlegmon
– Peripherally enhancing necrotic abscess
• Fat saturation → STIR, T2WI FS, T1WI C+ FS
○ Increases lesion conspicuity by suppressing signal from
epidural fat and vertebral marrow
• Signal alteration in spinal cord secondary to compression,
ischemia, or direct infection
• Anterior epidural abscess arises from adjacent discitis &
vertebral osteomyelitis
• Persistent epidural enhancement without mass effect after
treatment
○ Probable sterile granulation tissue or fibrosis, correlate
with ESR, CRP for activity
TOP DIFFERENTIAL DIAGNOSES
• Extradural metastasis
• Epidural hematoma
PATHOLOGY
• Staphylococcus aureus most common in postoperative
population, with Enterococcus next most frequent
• Predisposing factors
○ Intravenous drug abuse, immunocompromised state,
diabetes mellitus, chronic renal failure, alcoholism,
cancer, other chronic illnesses
○ Risk of epidural abscess in epidural anesthesia (5.5%)
– Especially in presence of indwelling catheters
CLINICAL ISSUES
• 0.5% incidence of epidural abscess from epidural
anesthesia for open aortic aneurysm repair
(Left) Sagittal T2WI MR shows
dorsal soft tissue disruption
from prior laminectomy ſt.
There are classic changes of
disc space infection at L4-5
with endplate destruction and
T2 hyperintensity as well
as ventral epidural abscess
extension st. (Right) Axial
T1WI C+ MR shows irregular
enhancement and destruction
of the endplates from disc
space infection .
Paravertebral extension is
seen into the psoas muscles
st. Epidural phlegmon
enhancement is present and
compresses the thecal sac ſt.
(Left) Sagittal T1WI C+ MR
shows metal artifact from
prior anterior and posterior
fixation ſt. The large dorsal
epidural loculated abscess
shows peripheral
enhancement with
compression of the thecal sac
and anterior cord
displacement. (Right) Axial
T2WI MR in patient status post
posterior lumbar interbody
fusion shows abscess
collection surrounding the
posterior spinal fusion
hardware (metallic
susceptibility ). Note edema
in the paraspinal muscles st.
349