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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_6033_Библиотеки_им_академика_М_И_Перельмана.pdf
26 Anterolateral Fixation in LLIF
LLIF Candidate
T-Score
< -2.5
No
261
Ye s
Facet Arthropathy
Grade ≥ 2
Degenerative Disc
Disease
No
No
Ye s
Degenerative
Scoliosis
Coronal or
Sagittal
Imbalance
Spondylolisthesis /
Ye s
Functional X-Rays
No
Spondylolysis
Grade ≥ 1
or Isthmic
No
Unstable
Adjacent Segment
Disease
Below
Ye s
Ye s
Ye s
No
1 or 2
Levels
Ye s
22 or 26mm
Cage
Ye s
Standalone
No
No
Fail Walking
Test
Ye s
Fig. 26.1 Algorithm for supplemental fi xation (Adapted from Malham et al. [ 5 ] )
Supplementary Fixation
+/-
Decompression
262
G.M. Malham et al.
Above a prior fusion, a wide stand-alone lateral
cage can be considered, but only if the spine is in
sagittal balance. A lateral plate with an interspinous
clamp is also a reasonable option in a balanced spine
and avoids dealing with preexisting hardware.
26.3.8 Previous Surgery
Prior microdiscectomy or laminectomy at the target LLIF warrants assessment of facet joint compromise and spinous process removal but does
not necessarily mandate supplemental fi xation.
26.3.9 Intraoperative Vertebral
Endplate Injury
Endplate injuries recognized during surgery or
identifi ed on the early postoperative imaging warrants pedicle screw fi xation to reduce subsidence.
26.3.10 Planned Section or
Unplanned ALL Rupture
With planned section of the ALL, cages with
integrated screws are used to secure the cage
prior to posterior bilateral pedicle screw fi xation
[ 10 , 11 ]. Unplanned ALL rupture, often detected
by an audible snap during trial or cage placement, should be treated the same, but if integrated
cages are not available, the salvage is a PLIF/
TLIF to avoid anterior cage migration.
Fig. 26.2 Lateral fi xation
with less rigidity in fl exion and extension than posterior fi xation. A 4-screw plate is more rigid than a
2-screw plate in all motion planes but is technically challenging to insert without psoas trauma.
The integrated cage with 1- or 2-screw fi xation
limits cage migration after ALL disruption. The
advantages of lateral fi xation on its own are that it
reduces operating time and avoids patient repositioning for posterior fi xation (Fig.
26.2 ).
26.4.2 Posterior Fixation
26.4 Which? Fixation Options
in LLIF
Biomechanical data indicates improved stability
of the spinal segment with lateral fi xation, posterior fi xation, or both [ 3 , 4 ].
26.4.1 Lateral Fixation
Separate lateral plates or integrated cage-screw
devices restrict axial rotation and lateral bending,
Posterior fi xation constructs provide substantial
rigidity to the segment in all planes – axial, coronal, and especially sagittal. Posterior fi xation also
maintains segmental lordosis. Percutaneous screws
add 1° of lordosis, while open screws allow the
option for osteotomies for increased sagittal correction [ 5 , 8 ]. Repositioning in the prone position
may also increase lordosis after lateral cage insertion. Importantly, pedicle screws protect against
cage subsidence and improve interbody fusion
rates. Bilateral pedicle screws remain the fi xation
of choice where stability is a concern and are the
standard against which other fi xations are judged.
26 Anterolateral Fixation in LLIF
263
Fig. 26.3 Bilateral pedicle screw-rod construct
Technique options :
(i) Pedicle screws
Bilateral pedicle screw-rod constructs provide
the most rigid biomechanical fi xation via a
traditional midline or bilateral paramedian
muscle-splitting (Wiltse) incision [
However, placement of the contralateral lower
screws in the lateral position raises sterility
concerns and is technically challenging.
Insertion of bilateral pedicle screws is easier in
the prone position, but this necessitates repositioning the patient. Hence, unilateral pedicle
screws inserted in the lateral position are an
option, but rigidity is reduced in all planes,
especially axial rotation, and anecdotally promotes ipsilateral unilateral fusion (Fig.
(ii) Facet screws
Transfacet screws inserted via a small midline incision, under fl uoroscopy, provide
rigidity comparable to bilateral pedicle
screws [ 12 ].
(iii) Cortical screws
Transcortical screws provide similar biomechanical rigidity to bilateral pedicle screws
despite a smaller diameter screw. They are
inserted from a midline approach with less
muscle retraction than for open pedicle
screws and medial to superolateral screw
26.3 ).
Fig. 26.4 Transcortical screws
orientation. Entering the cortical bone of the
pars, these screws have high pull out strength
in patients with reduced bone density [ 13 ]
(Fig. 26.4 ).
( i v ) Interspinous clamps
Of the fi xation options available, interspi-
4 ].
nous clamps offer the most technically
straightforward insertion via a small midline
incision in patients with intact spinous processes. They can be performed in a lateral or
prone position to effectively resist fl exionextension, but have limited stability in axial
rotation and lateral bending [ 14 ]. Thus, in
partnership with a lateral plate, addressing
each other’s relative weakness, together
they provide rigidity comparable to bilateral
pedicle screws.
26.4.3 Combination Lateral and Posterior Fixation
Combined constructs such as a lateral plate plus
contralateral unilateral pedicle screws or a lateral
plate with an interspinous clamp can be placed in
the lateral position to provide similar stability to
bilateral pedicle screws without repositioning the
patient. Other combinations are possible and
reasonable.
264
G.M. Malham et al.
Conclusion
Supplementary fi xation is indicated for three
main reasons in LLIF: to avoid subsidence, to
provide more stability, or to correct deformity.
Instrumentation is recommended in all patients
with osteoporosis, radiographic or clinical
instability, and intraoperative unplanned
events such as endplate injury or ALL rupture.
However, there is no comparative clinical data
on the multiple fi xation options. Biomechanical
cadaveric studies comparing stability of constructs may not predict the longevity required
to complete fusion nor have they been shown
to correlate with clinical outcome. Thus, until
there is more evidence, the default supplemental fi xation remains bilateral pedicle screws.
References
1. Ozgur BM, Aryan HE, Pimenta L, et al. Extreme lateral interbody fusion (XLIF): a novel surgical technique for anterior lumbar interbody fusion. Spine
J. 2006;6:435–43.
2. Jagannathan J, Sansur CA, Oskouian RJ, et al.
Radiographic restoration of lumbar alignment after
transforaminal lumbar interbody fusion. Neurosurgery.
2009;64:955–63.
3. Bess RS, Cornwall GB, Vance RE, et al. Biomechanics
of lateral arthrodesis. In: Goodrich JA, Volcan IJ,
editors. eXtreme lateral interbody fusion (XLIF). St
Louis: Quality Medical Publishing; 2008. p. 31–40.
4. Cappuccino A, Cornwall BG, Turner AWL, et al.
Biomechanical analysis and review of lateral lumbar
fusion constructs. Spine. 2010;35:S361–7.
5. Malham GM, Ellis NJ, Parker RM, Seex
KA. Maintenance of segmental lordosis and disc
height in standalone and instrumented extreme lateral
interbody fusion (XLIF). Clin Spine Surg. 2016.
10.1097/BSD.0b013e3182aa4c94 . In Press.
doi:
6. Tempel ZJ, Gandhoke GS, Okonkwo DO, Kanter
AS. Impaired bone mineral density as a predictor of
graft subsidence following minimally invasive transpsoas lateral lumbar interbody fusion. Eur Spine
J. 2015;24 Suppl 3:S414–9.
7. Pathria M, Sartoris DJ, Resnick D. Osteoarthritis of
the facet joints: accuracy of oblique radiographic
assessment. Radiology. 1987;164:227–30.
8. Marchi L, Amaral R, Oliveira L, et al. Stand-alone
lateral interbody fusion for the treatment of low-grade
degenerative spondylolisthesis. Scientifi c World
Journal. 2012;2012:456346.
9. Pimenta L, Turner AWL, Dooley ZA, et al.
Biomechanics of lateral interbody spacers: going
wider for going stiffer. Scientifi c World Journal.
2012;2012:381814.
10. Deukmedjian AR, Le TV, Baaj AA, et al. Anterior
longitudinal ligament release using the minimally
invasive lateral retroperitoneal transpsoas approach: a
cadaveric feasibility study and report of 4 clinical
cases. J Neurosurg Spine. 2012;17:530–9.
11. Uribe JS, Smith DA, Dakwar E, et al. Lordosis restoration after anterior longitudinal ligament release and
placement of lateral hyperlordotic interbody cages
during the minimally invasive lateral transpsoas
approach: a radiographic study in cadavers.
J Neurosurg Spine. 2012;17:476–85.
12. Voyadzis JM, Anaizi AN. Minimally invasive lumbar
transfacet screw fi xation in the lateral decubitus position after extreme lateral interbody fusion: a technique and feasibility study. J Spinal Disord Tech.
2013;26:98–106.
13. Matsukawa K, Yato Y, Imabyashi H, et al. Biomechanical
evaluation of the fi xation strength of lumbar pedicle
screws using cortical bone trajectory: a fi nite element
study. J Neurosurg Spine. 2015;23:471–8.
14. Wang JC, Spenciner D, Robinson JC. SPIRE spinous
process stabilization plate: biomechanical evaluation
of a novel technology. Invited submission from the
joint section meeting on disorders of the spine and
peripheral nerves, March 2005. J Neurosurg Spine.
2006;4:160–4.
Anterior Column Realignment
Juan S. Uribe , Chun-Po Yen , and Joshua M. Beckman
2 7
27.1 Introduction
The lateral retroperitoneal approach offers unique
access to the lumbar spine, specifi cally the anterior spinal column. This approach provides a
direct corridor with minimal tissue disruption for
a more substantial correction of sagittal, rotary,
and coronal deformities when compared to traditional posterior techniques [ 20 , 23 ]. Previously,
the amount of segmental lordosis achieved with
single or multilevel lateral interbody fusions was
limited by the anterior longitudinal ligament
(ALL). This drawback was circumvented with
the introduction of the anterior column realignment (ACR), which allows the vertebrae to “fi shmouth” open. This technique permits a signifi cant
amount of lordosis correction while maintaining
indirect decompression of the foramen and is
only limited by the shingling effects of the posterior elements.
Anterior column realignment (ACR) is a relatively new, minimally invasive technique for treating sagittal imbalance [ 9 , 10 ]. The ACR procedure
involves a lateral transpsoas approach to perform a
complete discectomy and deliberate release of the
anterior longitudinal ligament and annulus.
Hyperlordotic interbody cages are then placed and
fi xed with either 20 or 30° of lordosis. The proce-
J. S. Uribe (*) • C-. P. Yen • J. M. Beckman
University of South Florida , Tampa , USA
juansuribe@gmail.com
e-mail:
dure is completed by placing posterior instrumentation for stabilization or further correction of
sagittal plane deformity, using either MIS or open
techniques, depending on the desired posterior
release, surgeon preference, and experience.
In this chapter, relevant regional anatomy,
degree of sagittal correction, surgical technique,
applications, and potential complications will be
discussed. Sectioning of the ALL (also known as
the ACR) is a highly advanced lateral technique
and should only be performed by surgeons who
are experts in both minimally invasive (MIS) and
lateral surgery. The surgeon is working in very
close proximity to both the inferior vena cava/
iliac veins and the abdominal aorta/iliac arteries.
A complication can be potentially fatal.
27.2 Applications
The lateral MIS-ACR has been proposed as an
alternative to traditional open techniques (such as
the Smith-Peterson osteotomy) (SPO) and pedicle subtraction osteotomy (PSO) for adult spinal
deformity correction. Though open techniques
are time tested, they have been associated with
increased morbidity and blood loss with perioperative and postoperative complications ranging
from 15.5 to 80 % [
attempt to circumvent some of these complications, MIS techniques have been applied in the
treatment of spinal deformities and restoration of
spinopelvic harmony.
1 , 3 , 5 , 7 , 12 – 16 , 19 , 21 ]. In an
© Springer International Publishing Switzerland 2017
M.Y. Wang et al. (eds.), Lateral Access Minimally Invasive Spine Surgery,
DOI 10.1007/978-3-319-28320-3_27
265
266
J.S. Uribe et al.
In both cadaveric and clinical studies, the
ACR has been shown to increase segmental lordosis by 12–13° per level without disruption of
the posterior elements [ 1 , 9 , 10 , 17 , 23 ]. For com-
parison, the traditional open technique of a SPO
has a segmental lordosis correction of only 10°
per level [ 4 , 6 , 8 , 17 ]. The amount of lordosis
achieved from an ACR is typically inhibited by
posterior element obstruction. If the ACR is complimented with a Ponte osteotomy or SPO, it has
the potential of gaining lordotic correction on par
with that of a PSO but without the associated
blood loss and spinal shortening nature of the
procedure (Figs.
27.1 and 27.2 ).
27.3 Regional Anatomy
The MIS-ACR exposes spine surgeons to unfamiliar regional anatomy associated with the anterior spinal column such as visceral organs, the
autonomic plexus, and the great vessels. The
ALL itself is a very strong band of fi bers that
extend along the anterior aspect of the vertebrae
consisting of three layers: superfi cial, intermediate, and deep. It is typically thicker and more narrow at the level of the vertebral body (VB) and
thinner and wider at the level of the disc space
and more adherent to the disc than the VB [
10 ].
Directly anterior to the ALL at its lateral border lies the sympathetic plexus. It typically
resides where the psoas major meets the ALL and
is in direct communication with the lumbar
plexus through white and gray rami communicantes (via the paravertebral ganglia). These
communicating fi bers reside along the lateral
vertebral body and are rarely encountered at the
level of the disc space where an ALL release is
performed (Fig.
27.3 ).
The great vessels (aorta, inferior vena cava,
common iliac arteries/veins) reside along anterior lumbar vertebral bodies, immediately anterior to the ALL and the sympathetic plexus. The
aorta typically bifurcates 18 mm rostral to the
Fig. 27.1 Pre- and postoperative 3 ft standing scoliosis X-rays demonstrating an adult deformity case with global sagittal imbalance and the application of ACR technique at L3/L4 level
27 Anterior Column Realignment
267
L4–5 disc space, and the inferior vena cava bifurcates within 2 mm of the L4–5 disc space [ 11 ].
Between the ALL and the great vessels resides an
adipose-lined anatomic plane that allows blunt
dissection immediately dorsal to the vessels to
safely isolate the ALL for sectioning.
27.4 Surgical Technique
The MIS-ACR entails a more extensive dissection of critical anatomic structures (listed above)
from the lateral transpsoas retroperitoneal
approach. This procedure is highly dependent on
anterior- posterior (AP) and lateral fl uoroscopy
and detailed patient positioning. The patient is
positioned in the lateral decubitus position in the
same manner used for the traditional lateral
transpsoas approach. Laterality is typically dic-
tated by the concavity of the coronal deformity.
We choose to approach from the concave side so
that more levels can be accessed from a single
incision. If there is not a signifi cant coronal
deformity, then we choose to approach from the
right to place the more durable aorta or iliac
artery to the blind side and keep the veins on the
side of our operative fi eld. The most common
levels for ACR at our institution are L2/L3 and
L3/L4. The L4/L5 level is typically avoided due
to the anterior migration of the lumbar plexus.
The anterior lumbar column is accessed through
the typical lateral retroperitoneal transpsoas
approach with the use of directional triggered electromyogram (tEMG) to help prevent a lumbar
plexus injury. Once the retractor is docked in a safe
location (typically posterior third of the disc space
or working zone 3) [
22 ], a discectomy is performed,
and the endplates are prepared in the same manner
Fig. 27.2 Pre- and post-op lateral X-rays showing with detail the amount of segmentary lordosis at L3/L4 after ACR
procedure
268
Fig. 27.3 Cadaveric
anatomical dissection showing
the anatomical relationship of
the anterior longitudinal
ligament and nearby structures
J.S. Uribe et al.
Anterior
Sympathetic Plexus
Segmentary Vessel
Caudal
Anterior
ALL
Caudal
Posterior
Fig. 27.4 Intraoperative view of the L3/L4 lumbar interspace with the retractor in place after discectomy and
anterior longitudinal ligament dissection
as a basic lateral interbody fusion. The retractor is
then opened more anteriorly, and the ALL is identifi ed (Fig. 27.4 ). It is a thick (white) fi brous structure
bridging the two vertebral bodies anteriorly.
A natural anatomic plane is then developed
(with a blunt instrument) directly ventral to the
ALL and dorsal to the autonomic plexus and
great vessels. Under AP fl uoroscopic guidance,
ALL
Genitofemoral Nerve
L2/3
Iliopsoas Muscle
Posterior
Rostral
the blunt dissector is advanced while applying
slight posterior pressure against the ALL. Very
little resistance should be encountered during this
maneuver. Resistance means that the wrong plane
has been accessed and risk for vessel injury is
substantial. We only advance to the medial border of the contralateral pedicle (under AP fl uoroscopy) for safety reasons.
While the blunt dissector is protecting the
ventral vascular structures, bipolar cautery is
used to coagulate the ALL, and an annulotomy
blade is slid down the dissector making cuts in
and anterior to posterior direction. The surgeon
should never cut in a downward manner. Only
the fi rst two-thirds of the ligament need to be
sectioned (once again, for safety reasons), and
the remaining component is broken with a specifi cally designed disc space distractor. The dissector is slowly removed and the disc space
distractor is placed under AP fl uoroscopic guidance. The distractor is opened in a gradual manner (multiple minutes) until the fi nal third of the
ligament of broken. A hyperlordotic cage is then
placed with unicortical lateral screws to prevent
anterior migration (Figs.
27.5 , 27.6 , and 27.7 ).
27 Anterior Column Realignment
269
Fig. 27.5 Intraoperative fl uoroscopic anteroposterior images showing (from a to d ). The progression of dissection and
sectioning of the anterior longitudinal ligament and fi nal widening of the disc space
27.5 Potential Pitfalls
• Vascular anatomic position should be reviewed
prior to the case to assure the great vessels are
• A strict contraindication for ACR is the presence of a large anterior osteophyte such as
those seen in diffuse idiopathic skeletal hyperostosis (DISH). The natural anatomic plane is
typically obliterated and cannot be safely dissected without signifi cant risk of major vascular injury.
not too laterally oriented, and there is not an
aberrant vessel that crosses the fi eld.
• Specifi c detail must be applied to positioning
and fl uoroscopy. Any small variance from a
direct AP or lateral shot may allow anterior
migration of surgical instruments resulting in
a major vascular injury.
270
Fig. 27.6 Intraoperative
lateral fl uoroscopic images
showing before and after
sectioning of the anterior
longitudinal ligament and
lordosis gain
J.S. Uribe et al.
Fig. 27.7 Pre- and
postoperative CT sagittal
images showing the amount
of lordosis achieved after the
ACR procedure