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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_6013_Библиотеки_им_академика_М_И_Перельмана.pdf
P O RTA L S / E X P O S U R ES
P I T F A L L S
• Improper incision placement can make
the disk excision and instrumentation
very difficult to perform and may
compromise implant insertion.
• Be aware of the correct disk level to be
addressed in cases in which there is
transitional lumbosacral anatomy.
• Avoidance of electrocautery may reduce
the incidence of retrograde ejaculation.
Bipolar cautery or other means to
achieve hemostasis is recommended.
P O RTA L S / E X P O S U R ES
I N S T RU M E N T A T I O N
• Smooth-edged retractors are important
to avoid inadvertent vessel injuries.
• Proper illumination into the abdominal
cavity is crucial. A headlight or direct
fiberoptic lighting is helpful.
Procedure 32 | Anterior Lumbar Interbody Fusion 299
FIGURE 32-4
P O RTA L S / E X P O S U R ES
C O N T RO V E R S IE S
• The use of a cosurgeon (general or
vascular surgeon) during the anterior
lumbar approach is dependent upon
the individual surgeon’s training and
expertise.
C-arm
FIGURE 32-5
A
B
FIGURE 32-6
C-arm
300 Procedure 32 | Anterior Lumbar Interbody Fusion
n
P O RTA L S / E X P O S U R ES
P E A R LS
• If the L5-S1 disk lies low in the pelvis
and is at an acute angle, the incision
will need to be lower on the abdomen
to allow the proper trajectory for disk
excision and graft placement.
• Always confirm the disk level with
fluoroscopy or radiographs to avoid
wrong-level surgery.
Blunt dissection is performed down to the anterior disk space.
n
Retractors are placed appropriately, depending on the disk space being
addressed. At L4-5, the aorta and inferior vena cava are retracted left to right.
At L5-S1, the middle sacral artery and vein are ligated (see Figure 32-4), and
the iliac veins are retracted laterally.
Procedure
Step 1
n
The anterior disk is incised with a long-handled no. 10 scalpel.
n
An end-plate elevator is used to develop the interval between the subchondral
bone and the cartilaginous end plate (Figure 32-7).
n
S T E P 1 P EA R L S
• Properly developing the interval
between the subchondral bone and the
cartilaginous end plate with a disk
elevator is crucial for efficient and
complete disk excision.
• If the end plates are sclerotic, a bone
hook can be used to perforate the
subchondral bone in several areas to
expose bleeding bone.
Disk rongeurs are used to remove large disk fragments (Figure 32-8).
n
Long-handled curettes are used to gently scrape the end plates of any remaining
pieces of cartilage and to expose bleeding bone.
S T E P 1 P IT FA L L S
• When incising the disk margins, the
sharp edge of the blade should always
point away from the vascular structures.
• When exiting and entering the disk
space during excision, maintain an
awareness of the location of the
vascular structures. Veins can easily slip
beneath the edges of retractors.
• Be aware of the orientation of the end
plates when excising the disk to avoid
disruption of the subchondral bone.
FIGURE 32-7
FIGURE 32-8
Procedure 32 | Anterior Lumbar Interbody Fusion 301
S T E P 2 P EA R L S
• Slowly distract the collapsed disk spaces
to allow for viscoelastic expansion and
restoration of disk height. Paddled
distractors of progressive heights are
inserted and rotated in the interbody
space to restore segmental lordosis.
• Ensure that the implant is inserted
parallel to the end plates.
S T E P 2 P IT FA L L S
• Inserting the implant at an angle not
parallel to the end plates will fracture
the subchondral bone and result in
implant settling and loss of lordosis.
• Overaggressive insertion or impaction
of the implant can cause fracture and
displacement of the posterior vertebral
body and subsequent thecal sac or
nerve root impingement.
S T E P 2
I N S T RU M E N T A T I O N /
I M P L AN TAT IO N
• Various anterior lumbar interbody
implants are available, including
allograft, titanium, polyether ether
ketone (PEEK), and absorbable. They
come in many shapes and sizes.
Step 2
n
Distraction is applied to the disk space to restore proper disk space height.
n
A trial implant or sizing device is used to determine the appropriate-sized graft
or cage.
n
An implant is selected that corresponds to the correct trial implant.
n
The implant is packed with bone graft material and inserted into the disk space
in an anterior to posterior direction (Figures 32-9 and 32-10). The insertion
device distracts the disk space as the implant is inserted.
FIGURE 32-9
FIGURE 32-10
302 Procedure 32 | Anterior Lumbar Interbody Fusion
n
S T E P 2 C ON T R O V ER S I E S
• The use of an anterior plate for
interspace fixation or buttressing of the
implant is surgeon dependent.
• Many interbody implants now
incorporate screw fixation into the
implant itself, obviating the need for
plate fixation.
• Many surgeons believe anterior
implants alone are not stable enough
to obtain a successful fusion.
However, recent studies (Burkus, 2005)
using bone morphogenetic protein
(BMP) in conjunction with standalone
devices have reported a fusion rate of
up to 99%.
Fluoroscopic imaging is used to ensure correct positioning of the implant.
n
If used, anterior instrumentation is applied across the disk space (Figures 32-11,
32-12, and 32-13).
n
Interbody implants that incorporate screw holes for internal fixation are inserted
in a similar manner with the insertion device (Figure 32-14).
n
Following insertion, a drill guide is attached to the implant and drill holes are
made for screw insertion (Figure 32-15).
n
The screws are then inserted through the implant, through the superior and
inferior end plates and into the vertebral body (Figures 32-16 and 32-17).
FIGURE 32-11
FIGURE 32-12
FIGURE 32-13
Procedure 32 | Anterior Lumbar Interbody Fusion 303
FIGURE 32-14 FIGURE 32-15
FIGURE 32-16
FIGURE 32-17
Postoperative Care and Expected Outcomes
n
Patients are started on clear liquids, and their diets are advanced as tolerated.
n
Patients are mobilized on postoperative day 1 and encouraged to ambulate as
tolerated.
n
A simple lumbar corsette brace may be recommended for 6 weeks postopera-
tively, but many surgeons do not routinely use bracing.
n
If the procedure is a standalone anterior lumbar interbody fusion, patients are
typically discharged on postoperative day 2 or 3.
n
A successful fusion rate in the 90% range can be expected with an anterior
lumbar interbody fusion when combined with a posterior stabilizing procedure
or when BMP is used in conjunction with an implant stabilized anteriorly.
304 Procedure 32 | Anterior Lumbar Interbody Fusion
Evidence
Brau SA. Mini-open approach to the spine for anterior lumbar interbody fusion:
description of the procedure, results and complications. Spine J 2002;2:216-23.
This is a review of the complications of the anterior lumbar approach using a
mini-open technique (Level IV evidence).
Burkus JK, Gornet MF, Schuler TC, Kleeman TJ, Zdeblick TA. Six-year outcomes of
anterior lumbar interbody arthrodesis with use of interbody fusion cages and
recombinant human bone morphogenetic protein-2. J Bone Joint Surg Am
2009;91:1181-9.
A 98% fusion rate was achieved with standalone tapered titanium cylinder
cages and rh-BMP2. Improvements in Oswestry Disability Index and SF-36 scores
were maintained at the 6-year follow-up (Level II evidence).
Burkus JK, Sandhu HS, Gornet MF, Longley MC. Use of rhBMP-2 in combination
with structural cortical allografts: clinical and radiographic outcomes in anterior
lumbar spinal surgery. J Bone Joint Surg Am 2005;87:1205-12.
This is a prospective investigational device exemption study evaluating the use
of BMP in anterior lumbar fusion with cortical allograft dowels. The fusion rate
was 99% (Level I evidence).
Sasso RC, Kitchel SH, Dawson EG. A prospective randomized controlled clinical
trial of anterior lumbar interbody fusion using a titanium cylindrical threaded
fusion device. Spine 2004;29:113-22.
Titanium cylinder cages had better results when used alone than did femoral
allograft implants (Level II evidence).
P R O C ED U R E 3 3
Transforaminal Lumbar
Interbody Fusion
Kamal R.M. Woods, Eli M. Baron, Neel Anand, and
Alexander R. Vaccaro
I N D I CAT I O NS P I T F A L L S
• Osteoporosis or severe osteopenia: may
easily fracture end plates during surgery
or have telescoping of cage into
vertebra
• Severe disk space collapse: may be
difficult to achieve adequate disk space
height without injuring end plates
I N D I CAT I O NS
C O N T RO V E R S IE S
• Multilevel (>3 levels) degenerative disk
disease
• Lytic and high-grade spondylolisthesis
T R E A T M E N T OP T I O N S
• Anterior lumbar interbody fusion (ALIF)
• Posterior lumbar interbody fusion (PLIF)
• Lateral transpsoas interbody fusion
(extreme lateral interbody fusion [XLIF],
direct lateral interbody fusion [DLIF])
• Posterolateral fusion
• Axial transsacral lumbar interbody
fusion (AxiaLIF)
• Laminoforaminotomy
Indications
n
Spondylolisthesis (particularly isthmic and degenerative etiology)
n
Symptomatic degenerative disk disease
n
Recurrent disk herniation
n
Radiculopathy caused by foraminal stenosis from loss of disk height
n
Augmentation of distal end of long posterior scoliosis fusion constructs
n
Segmental coronal collapse and tilt with unilateral radiculopathy
Examination/Imaging
n
Pertinent preoperative history and physical are essential to the diagnosis and
surgical decision making. The most symptomatic side (right versus left) is
selected for the transforaminal lumbar interbody fusion (TLIF) approach.
n
Plain radiographs are obtained to assess for listhesis, other deformities, osteo-
penia, and spina bifida occulta. Dynamic studies should be performed to rule
out dynamic instability. Figure 33-1, A to C shows anteroposterior (AP) and
flexion extension films demonstrating a grade I degenerative spondylolisthesis
at L4-5 in a 60-year-old male who had undergone laminoforaminotomy and
facet cyst excision years earlier and then presented with recurrent leg and back
pain.
n
Magnetic resonance imaging (MRI) is done to identify degenerated interverte-
bral disks and possible compression of neuronal elements. Figure 33-2 shows
T2-weighted sagittal MRI in the same patient, showing facet cyst and severe
stenosis at the level of L4-5 spondylolisthesis.
n
Computed tomography (CT) is done to exclude pars defect in cases of spondy-
lolisthesis. CT also helps to assess bone quality and anatomy in preparation for
instrumentation.
n
Plain lateral radiograph or fluoroscopic imaging is done after patient positioning.
Often, a preoperative degenerative spondylolisthesis will reduce with the patient
positioned prone with the hips extended.
306 Procedure 33 | Transforaminal Lumbar Interbody Fusion
A
C
FIGURE 33-1, A-C
B
Procedure 33 | Transforaminal Lumbar Interbody Fusion 307
FIGURE 33-2
Pedicle
screws
A
FIGURE 33-3, A-B
L4 pedicle
A
C
B
L4-5 disc
L5 pedicle
B
A
B
Surgical Anatomy
n
It is important to expose the ipsilateral spinous process, lamina, facet, and
transverse process. The working zone for the TLIF approach is bounded medially
by the traversing nerve root and thecal sac, superiorly by the exiting nerve root,
and inferiorly by the pedicle of the vertebra below the disk space. Note that the
exiting root hugs the undersurface of the superior pedicle, allowing for a safe
work zone.
n
Figure 33-3 shows lateral (A) and cross-sectional (B) schematics demonstrating
working zone for TLIF and the relationship of exiting and traversing roots to the
disk space.
308 Procedure 33 | Transforaminal Lumbar Interbody Fusion
P O S I TI O N I N G PI T FA L L S
• The hip-flexed position will open the
posterior interbody space and may
improve access to the disk; however,
this position reduces lumbar lordosis
and can lead to fixed sagittal
imbalance. Therefore the authors
do not recommend it.
• High-grade isthmic spondylolisthesis or
significant kyphosis at the level of the
slip may necessitate a bilateral PLIF
rather than a TLIF, if a posterior
interbody approach is being taken.
P O S I TI O N I N G EQ U I P M EN T
• Jackson table
S T E P 1 P EA R L S
• Thinning the planned resection area
of the pars and facet joints with a
high-speed burr makes removal easy
and less traumatic.
• All local bone resected, including bone
dust from drilling, is harvested for use
as autograft.
• The ligamentum flavum is not removed
in the absence of central stenosis.
• Similarly, the traversing nerve root is
not exposed, and the vascular sleeve
and fat over the exiting nerve are
maintained.
• Use fluoroscopy to confirm appropriate
placement of the osteotome for the
initial transverse cut, to ensure that this
is low enough to avoid injuring the
exiting nerve root. At L5-S1, the
authors recommend using a burr over
an osteotome, because the L5 root lies
lower in the foramen, and use of the
osteotome may have a theoretically
higher risk of injuring the L5 dorsal root
ganglion. Because the spinal canal is
wider at this level, a variant of the TLIF
can be performed here without a
true inferior facetectomy and is
recommended, if possible, to prevent
any inadvertent injury to the exiting L5
nerve root.
Positioning
n
The patient is prone with the abdomen free of any compression to reduce
venous congestion.
n
The thigh is neutral or slightly extended.
n
Check the final positioning on the operating room table with a plain radiograph
or fluoroscopy.
Portals/Exposures
n
The standard midline incision with subperiosteal exposure of the pertinent
posterior osseous elements may be performed.
n
Alternatively, the surgical exposure may be achieved by the Wiltse paraspinal
approach.
n
Some minimally invasive approaches (e.g., with tubular retractors) use a muscle-
splitting technique.
n
If no central decompression is being performed, the midline posterior ligamen-
tous and osseous structures are preserved.
Procedure
Step 1
n
A subperiosteal exposure is performed. The facet complex corresponding to the
disk space being fused is exposed in its entirety. The transverse process and pars
interarticularis of the caudal level are also exposed. The pars and transverse
process of the rostral level are exposed, while making sure the supraadjacent
facet capsule is not violated.
n
The inferior facet is removed from the cephalad level using a
should be done by making a transverse cut in the pars interarticularis just above
the lower vertebrae’s pedicle. Although this usually corresponds to the top of
the superior articular facet of the lower vertebrae, one must be cautious while
doing this in the degenerative spine, because one may be pushed upward by
the osteophyte and inadvertently make the cut higher along the pars, which
could injure the exiting nerve root. The authors confirm the position on fluoroscopy before making the cut. Figure 33-4 is an intraoperative fluoroscopic image
showing the position of the osteotome at the level of the top of the lower
1
osteotome. This
4
S T E P 1 P IT FA L L S
• Epidural bleeding can decrease
visualization and potentially increase the
risk of inadvertent nerve root injury. The
authors use low-power bipolar cautery
over the disk space as needed.
FIGURE 33-4