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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_6031_Библиотеки_им_академика_М_И_Перельмана.pdf
270
A.S. Kanter and M.B. Maserati
more likely to occur in the absence of posterior
fi xation [ 4 , 10 , 11 , 15 , 16 , 18 ]; however, delayed
subsidence is less likely to occur in the absence
of intraoperative end-plate violation.
Wound infection has been reported but
remains a rare occurrence, as for most minimally
invasive procedures, likely due to small incision
size and minimal tissue trauma [ 9 , 10 , 18 , 19 ].
Routine antisepsis measures, including preoperative administration of intravenous antibiotics and
copious antibiotic irrigation prior to closure,
remain the principal defense against infectious
complications. Another wound complication that
has been reported is that of incisional hernia [ 15 ,
16 ]. This complication may be avoided in most
cases by ensuring reapproximation of the fascia
and lateral abdominal wall prior to skin closure.
Finally, paralytic ileus [ 9 , 15 , 16 , 19 ] and gas-
tric volvulus [ 15 , 16 ] have been reported follow-
ing the lateral approach, with the latter requiring
surgical repair. These complications are likely
the result of intolerance of the abdominal contents to manipulation associated with their anterior mobilization prior to retractor insertion. Care
should thus be taken to minimize such manipulation, although it is not likely that these complications can be entirely avoided with a procedure
such as the lateral transpsoas interbody fusion.
This is particularly true when one considers the
consequences of insuffi cient anterior mobilization of the bowel and peritoneum, which can be
potentially catastrophic.
Conclusions
The lateral approach to the lumbar spine is a
powerful new tool that provides direct access
to the anterior spinal column without many
of the limitations of traditional anterior and
posterior approaches, affording unparalleled
access to the intervertebral space without
the need for transgression of the neural ele-
ments or abdominal viscera. It is ligament
sparing and muscle sparing, offering advan-
tages over PLIF and TLIF procedures, and
does not require the assistance of an access
surgeon such as with the ALIF procedure.
Furthermore, complications such as durotomy,
arachnoiditis, and epidural fi brosis – problems
with which spine surgeons have become all
too familiar – are not of signifi cant concern
with the lateral approach.
Still, the lateral approach is itself associated with a host of potential approach-related
complications. Neurologic complications are
a signifi cant concern with the lateral approach
and are primarily the result of blunt or traction injury to the lumbar plexus or one of its
branches such as the genitofemoral nerve.
Direct trauma to the psoas muscle, even when
minimal, typically produces transient anterior
thigh pain and hip fl exor weakness in many
patients. Of great concern is the potential for
catastrophic injuries to the retroperitoneal
viscera, principally the colon and great vessels. Finally, the potential for graft-related
complications, including end-plate violation
and subsidence, is signifi cant particularly if
discectomy and end-plate preparation are too
aggressive and if too large a graft is chosen.
Avoidance of these complications, as for
any surgery, begins with selection of an appropriate candidate for the lateral transpsoas
interbody fusion procedure. In particular,
attention should be paid to any history of
abdominal surgery, to the presence of rotational deformity, and to the relative contribution of posterior spondylotic changes to the
stenosis being treated. Careful examination of
preoperative imaging and constant awareness
of the proximity of the retroperitoneal contents are critical to avoiding visceral injury.
Positioning should be accomplished while
minimizing traction on the lumbar plexus.
Continuous EMG monitoring should be used
throughout the approach and psoas traverse to
prevent injury to the motor components of the
plexus. Limiting retractor opening to the minimum required for discectomy and graft insertion decreases the potential for injury to the
psoas muscle and the lumbar plexus.
Using these strategies, it is possible to safely
and effectively perform the lateral approach
even in the setting of severe rotational deformity. The lateral approach procedure is a
uniquely powerful tool in the contemporary
spine surgeon’s armamentarium.
27 Complications of the Lateral Lumbar Transpsoas Approach
271
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Garfi n SR, et al. Incidence and prevention of intervertebral
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Minimally Invasive Anterior Column Reconstruction for Sagittal Plane Deformities
Armen Deukmedjian and Juan S. Uribe
2 8
28.1 Introduction
Many factors are involved in the surgical
management of adult spinal deformity, including
maintenance of coronal and sagittal balance as
well as spinopelvic harmony [ 1 – 5 ]. Adult spinal
deformity (ASD) is believed to develop because
of asymmetrical degeneration of discs, osteoporosis, and vertebral body compression fractures
[ 6 ]. Presenting symptoms of this condition pri-
marily include radiculopathy, chronic low back
pain, and neurogenic claudication caused by concurrent spinal stenosis [ 7 , 8 ].
Studies by Schwab et al. [ 9 , 10 ], Glassman
et al. [ 11 , 12 ], and others [ 13 ] have demon-
strated that in the treatment of congenital and
acquired deformity, correction of sagittal alignment to an SVA (sagittal vertical axis) < 5 cm
leads to improved HRQOL outcomes. With a
positive sagittal alignment, there is increased
stress on the axial musculature, which in turn
leads to abnormal degenerative changes in the
disc spaces, resulting in further imbalance and
serving a self- perpetuating cycle. A high postoperative SVA also increases the risk for pseudarthrosis, adjacent segment disease, and
Figures 28.1, 28.2, 28.3, 28.4, 28.5, and 28.6 and some
text reproduced with permission from the Journal of
Neurosurgery: Spine.
A. Deukmedjian , M.D. (*) • J. S. Uribe , M.D.
University South Florida , Tampa , FL , USA
e-mail: juansuribe@gmail.com
proximal functional kyphosis [ 14 – 16 ]. Although
currently no practice guidelines exist regarding
MIS sagittal deformity correction, in addition to
the SVA, here are a few key questions that
should be addressed during the treatment
decision-making process:
1. Is the thoracic kyphosis within the normal
range of 20°–40°? [ 17 ]
2. Is the lumbar lordosis within 9° of the pelvic
incidence? [ 1 , 4 , 18 ]
3. Is the pelvic tilt < 25°?
4. How many degrees of sagittal correction is the
goal?
5. Are MIS techniques feasible or would traditional open procedures be indicated?
Despite the many benefi ts of minimally inva-
sive surgery (MIS), one of the limitations of MIS
techniques is that up until now they have been
unable to improve sagittal balance signifi cantly
[ 19 ]. Sagittal imbalance is traditionally managed
with posterior shortening osteotomies, anterior
lengthening maneuvers, or both. Classically,
closing wedge osteotomies include a SmithPetersen osteotomy (SPO), a pedicle subtraction
osteotomy (PSO), or a vertebral column resection (VCR), which have been reported to have a
41 % complication rate in ASD [ 20 , 21 ]. Major
complications in revision adult deformity surgery were reported by Cho et al. to be 34 % in a
retrospective review of 141 patients [ 22 ].
For these reasons, alternative minimally
invasive techniques with reduced morbidity are
being proposed for improving sagittal balance
in ASD. A few examples of this cutting-edge
M.Y. Wang et al. (eds.), Minimally Invasive Spinal Deformity Surgery,
DOI 10.1007/978-3-7091-1407-0_28, © Springer-Verlag Wien 2014
273
274
A. Deukmedjian and J.S. Uribe
technology that will be explored in this chapter
include:
1. Sectioning the anterior longitudinal ligament
(ALL) with placement of a hyperlordotic cage
[ 23 , 24 ] (anterior column release-ACR)
2. Lateral transpsoas hybrid PSO/VCR
Also, less invasive facetectomy in conjunction
with the prior techniques can potentially provide
additional lordosis when compression is applied
to the construct having the interbody implant as a
pivot. In addition, a recent report demonstrates
that signifi cant sagittal correction can be achieved
using multilevel MIS transforaminal lumbar
interbody fusions (TLIF) in conjunction with
percutaneous pedicle screw fi xation, which in
itself is a hybrid open-MIS technique that will
need to be explored further [ 25 ]. Up to this point,
literature on these techniques has been scarce,
and most reports are scattered with no homogeneity or agreement on techniques. We will
attempt here to systematically describe several
MIS options in the treatment of sagittal imbalance, as well as the anatomy encountered from
the lateral approach.
28.2 Patient Selection
In addition to technological advancements in
spine instrumentation that allow us to treat different pathologies more effi ciently, our understanding of the optimal relationship between the spine
and pelvis has evolved. We now understand that
if certain spinopelvic parameters are realized
during surgical management, patient satisfaction
and overall outcomes are improved, as well as a
potential reduction in adjacent segment disease.
The goals often cited are:
1. Sagittal vertical axis < 5 cm
2. Pelvic incidence within 9° of lumbar lordosis
3. Pelvic tilt < 25°
In the not-so-distant past, it was adequate to
work up a patient with intractable low back
pain with a lumbar x-ray only. However, given
what we now know about spinopelvic harmony,
it almost seems an injustice to our patients to
not obtain standing spine x-rays with a 36″
cassette. Although at this point the majority of
spine surgeons are not analyzing sagittal balance and pelvic parameters, it seems that
national spine organizations for both neurosurgery and orthopedic surgery are encouraging
their members to embrace these new philosophies. Hopefully in the near future, 3′ standing
x-rays of the entire spine will be available to all
spine surgeons and performed on all patients
evaluated for surgery. It must be realized that it
can be dangerous to treat all patients the same
and that each patient must be treated on an individual basis. However, much like with minimally invasive surgery, each patient should be
viewed with a “new eye,” with the goal of safely
attaining spinopelvic harmony in the most minimalistic manner possible.
28.3 Advantages and Disadvantages
As discussed previously, open surgical techniques for the correction of sagittal imbalance
include posterior shortening osteotomies/VCR
and anterior release. With anterior release, historically there has been signifi cant approachrelated morbidity, limiting its utility [ 26 ].
Posterior osteotomies are also limited by long
operative times, heavy blood loss, signifi cant
postoperative pain, and possible neurologic compromise related to the manipulation of neural elements. However, even given the signifi cant
morbidity associated with a PSO, it is currently
the most effective means of improving sagittal
balance, assuming a 30° correction per level of
PSO. It also enables the surgeon to provide direct
neural decompression. Though less evidence
exists regarding MIS ALL release, recent literature suggests that through the lateral transpsoas
approach, we are able to achieve 10–15° of sagittal correction per level of ALL released, with
much shorter operative times and reduced morbidity [ 23 , 27 , 28 ]. However, we must be aware
that further study is necessary to be able to reliably reproduce MIS techniques for the correction
of sagittal imbalance.
28 Minimally Invasive Anterior Column Reconstruction for Sagittal Plane Deformities
275
28.4 Anterior Longitudinal Ligament Section via the Lateral Transpsoas Approach
Recent advances in minimally invasive spine
surgery allow for options in the treatment of
spinal deformity, as many new techniques may
offer similar or even improved clinical and
radiographic outcomes with less morbidity than
conventional approaches [ 29 ]. In particular, the
lateral retroperitoneal or retropleural approach
allows access to the spine with minimal tissue
disruption along a relatively bloodless plane
and has been shown to preserve coronal and
sagittal balance [ 30 , 31 ]. However, in cases of
fi xed sagittal imbalance, ALL release (anterior
column release-ACR) may be useful to restore
proper alignment, as it can potentially provide
sagittal correction similar to an SPO based on
emerging data [ 23 , 27 , 32 ]. This requires fur-
ther investigation as the technique becomes
more utilized.
As with any operation, meticulous preoperative planning and identifi cation of appropriate
candidates for ACR is essential. We realize that
this is an evolving technique still with much left
to discover; however, we hope that in describing
our method of performing an ACR, surgeons may
be encouraged to attempt or modify this procedure with a goal of continuous improvement.
Releasing the ALL is technically demanding
and requires a thorough understanding of the
regional anatomy of the lateral retroperitoneal or
retropleural approach to the spine. Though it
reduces some complications associated with posterior approaches, it is associated with its own
unique set of risks in addition to those related to
the standard MIS lateral access. As with other
MIS techniques, there is a signifi cant learning
curve and this will likely foster initial skepticism
given the potential complications associated with
an ACR. However, the potential benefi t to
patients is signifi cant and thus should be explored
further.
As with preoperative evaluation for any
planned lateral retroperitoneal approach, it is
essential to evaluate the patient’s MRI to
determine the course of the great vessels and
where the bifurcation occurs [ 33 , 34 ]. In addi-
tion, care must be taken not to injure the ilioinguinal, iliohypogastric, or lateral femoral
cutaneous nerves when accessing the retroperitoneum [ 34 – 36 ].
However, given its posterior to anterior
course along the iliopsoas muscle at the most
frequently accessed levels (L2/3 and L3/4), the
genitofemoral nerve is particularly at risk.
Depending on its course, opening the retractor
may cause a neuropraxia that is likely dependent on both the timing and amount of stretch of
the nerve. Risk of injury to this nerve may also
occur when performing anterior interspace dissection to reach the ALL [ 37 ]. Although the use
of directional electrophysiologic monitoring
can help minimize nerve injury during the lateral approach, the genitofemoral nerve is mainly
sensory and unable to be monitored without
scrotal or labial electrodes [ 38 ].
Another pitfall comes with dissecting the
sympathetic plexus and great vessels off the ALL
using the curved custom retractor, which carries
the risk of a potentially catastrophic aortic or IVC
injury. The target of the retractor blade is the
plane of dissection dorsal to the sympathetic
plexus/great vessels and ventral to the ALL.
However, a unique problem associated with this
procedure is dissection in the plane ventral to the
sympathetic plexus and dorsal to the great vessels. If this occurs unbeknownst to the surgeon,
inadvertent damage may be done to the sympathetic plexus unilaterally. At this point ramifi cations of such an injury have been unexamined
and require further study. It is likely that injuries
occur during these dissections to the gray and
white rami communicantes, which connect the
sympathetic plexus to the spinal nerve roots and
generally run on the lateral aspect of the inferior
third of the vertebral bodies. However, given the
many overlapping connections existing between
these structures, it is unlikely that injury at one or
two levels will produce any signifi cant clinical
consequence.
After reaching the contralateral interspace
with the retractor, a fresh 11-blade rather than
276
A. Deukmedjian and J.S. Uribe
monopolar electrocautery should be used to
incise the ALL in order to prevent thermal injury
to the sympathetic plexus and nearby vascular
structures. Opening the intradiscal distractor
should then produce a “fi sh-mouth” deformity at
the disc space. If this does not occur, it is likely
that the ALL is not fully cut. The variety of
hyperlordotic cages (10°–30°) enables the surgeon to fi t each disc space appropriately. It should
be placed between the anterior and middle third
of the disc space, which is anterior to the suggested position of a lumbar interbody cage placed
from the lateral decubitus position [ 37 , 39 ]. The
purpose of this is to provide ligamentotaxis of the
posterior longitudinal ligament (PLL) and indirect foraminal decompression at that level. One
or two transversely oriented screws are used for
the sole purpose of securing the cage and preventing ventral migration into the peritoneal cavity. The mechanical stability provided by these
screws is likely negligible.
28.5 Anatomic Consideration
28.5.1 Anterior Longitudinal Ligament
The ALL is a strong band of fi bers extending
along the anterior aspect of the vertebrae. It widens as you move caudad along the spine and is
thicker in the thoracic than the cervical or lumbar
region [ 40 – 42 ]. In the lumbar spine, the ALL tra-
verses the anterior aspect of all VB and disc
spaces and is composed of three layers: superfi cial, intermediate, and deep. The superfi cial layer
traverses four or fi ve vertebral bodies, while the
intermediate layer covers two or three vertebral
bodies. The deep layer of the ALL covers only
the individual vertebral bodies and attaches from
one VB to the next. The ALL is thinner and wider
at the level of the disc but thicker and narrower at
the vertebral bodies. Also, it is more strongly
adherent to the intervertebral disc than the middle of the vertebral body, making mobilization at
the disc space diffi cult. There are oval apertures
at the lateral aspect of the ligament to allow passage of vessels (Fig. 28.1 ) [ 40 – 42 ].
Fig. 28.1 Sympathetic plexus. Photograph during cadaveric dissection demonstrating the sympathetic plexus
retracted off the anterior longitudinal ligament at the L3/4
disc space. Note the genitofemoral nerve crossing the disc
space moving posterior to anterior. Inset demonstrates the
position of the cadaver during dissection
28.5.2 Lumbar/Sympathetic Plexus
Neural structures at risk during this procedure are
similar to those in the standard lateral approach
[ 37 , 39 , 43 ]. However, because it courses dorsal
to ventral in the psoas major, of all the lumbar
plexus nerves, the genitofemoral nerve (L1, 2) is
especially at risk as it crosses the L2/3 and L3/4
disc spaces. At the caudal end of the L4 VB, it
has moved anterior to run along with the sympathetic plexus.
The sympathetic plexus is a paired bundle
of nerves running along the anterolateral border of the vertebral bodies in the lumbar spine
that functions as part of the autonomic nervous
system via fi bers to the inferior mesenteric ganglion [ 40 , 41 ]. It lies along the lateral border of
28 Minimally Invasive Anterior Column Reconstruction for Sagittal Plane Deformities
Fig. 28.2 Anterior longitudinal ligament and sympathetic
plexus. Illustrated photograph
during cadaveric dissection
demonstrating the relationship between the anterior
longitudinal ligament and the
sympathetic plexus. Note the
complex network of
communicating nerves in
connection with the
sympathetic plexus. Inset
demonstrates the position of
the cadaver during dissection
277
the ALL, where it meets the psoas major, and
may be encountered during an ACR (Fig. 28.2 ).
It is in communication with the lumbar plexus,
with information arriving at the paravertebral
ganglia through the white rami communicantes
and leaving via the gray rami communicantes.
These communicating fi bers run along the inferolateral aspect of the VB and generally are not
encountered at the disc space where an ACR is
performed.
28.5.3 Great Vessels
The aorta and the IVC lie along the left and right
anterior lumbar VB border, respectively. Even
when intimately associated with the ALL, there
is an adipose-lined anatomic plane allowing dissection dorsal to the great vessels. There are generally four paired lumbar (segmental) arteries,
which arise from the aorta and course laterally
around the vertebral body, thus avoiding the disc
space [ 41 , 43 – 45 ]. [ 44 , 45 ] The aorta bifurcates
into the right and left common iliac arteries
18 mm rostral to the L4/5 disc space, while the
right and left common iliac veins converge to
form the IVC within 2 mm of the L4/5 disc space
(Fig. 28.3 ) [ 33 ].
Retroperitoneal transpsoas approach involves
traversing the nerves of the lumbar plexus both
within and outside of the psoas muscle. There are
four major nerves traveling outside of the psoas
muscle, namely, subcostal (T12), iliohypogastric
(L1), ilioinguinal (L1), and lateral femoral cutaneous (L2–L3) nerves. They originate from the
posterior border of the psoas muscle and descend
obliquely through the retroperitoneal space.
These free nerves are most vulnerable at the initial stages of the approach during abdominal
muscle and retroperitoneal dissection superfi cial
to the psoas muscle and hence necessitate delicate blunt dissection [ 35 ]. The genitofemoral
(L1–L2) nerve initially travels within the psoas
muscle, across the L2/3 disc space, for a short
distance before emerging and continuing on the
anterior surface of the muscle.
The L2, L3, and L4 roots merge to form the
femoral nerve which courses deep within the
psoas muscle to pass under the inguinal ligament
prior to giving off the cutaneous (medial/intermediate femoral cutaneous/infrapatellar branch/
saphenous nerve) and muscular branches.
Variation in proximal trajectory of the femoral
nerve has been described as it traverses the psoas
muscle [ 46 , 47 ]. Though anatomical variations of
the lumbar plexus have been described in the
278
Fig. 28.3 Great vessels.
Illustrated photograph during
cadaveric dissection in the
right lateral decubitus
position ( inset ). Note the
inferior vena cava ventral to
the anterior longitudinal
ligament on the contralateral
side. The aorta here is being
retracted. Notice also the
lumbar segmental artery
arising from the aorta. The
sympathetic plexus is being
retracted with the aorta
A. Deukmedjian and J.S. Uribe
literature, large population studies to establish a
more accurate measure of the prevalence of the
surgically relevant variability are lacking [ 48 , 49 ].
Variations in the trajectory of the femoral nerve
should be strongly considered when establishing
an operative corridor with utilization of directional EMG monitoring to prevent nerve injury.
The obturator nerve (L2–L4) courses through the
psoas muscle posterior to the femoral nerve. It
emerges from the medial aspect of the psoas
muscle and travels just lateral to the sacrum prior
to exiting the pelvis though the obturator foramen. Finally, the sympathetic plexus runs on the
anterior surface of the vertebral body and is at
risk especially with lateral corpectomies or anterior longitudinal ligament (ALL) releases.
The fi bers of the sympathetic plexus/ganglion
are found along the lateral edge of the ALL and
have communicating branches with lumbar
plexus nerves. The communicating branches consist of the white (presynaptic) and gray (postsynaptic) rami communicantes. Moreover, these
fi bers generally reside at the inferior aspect of the
vertebral body.
The intended trajectory of the lateral retroperitoneal dissection is mid-vertebral body in the
A-P plane for the placement of intervertebral
cage. The approach is anterior to the neural foramen and hence vulnerable to lumbar nerve injury
rather than specifi c root injury. Lumbar nerves
have contributor from multiple roots, therefore a
much more clinically signifi cant outcome if
injured. All nerves of the lumbar plexus have a
dermal sensory representation, except for the
intrinsic motor branches supplying the psoas
muscle. The clinical diagnosis of specifi c lumbar
plexus nerve injuries can sometimes depend on
overlapping sensory defi cits, which can make
diagnostic evaluation more diffi cult.
28.6 Operative Considerations
After the induction of general anesthesia and
positioning in the lateral decubitus position, fl uoroscopy is utilized to ensure proper orthogonal
visualization of the target segment on anteriorposterior and lateral views. The skin is marked
using fl uoroscopic guidance and then incised.
The retroperitoneal space is entered after gentle
splitting of the abdominal wall muscles and the
transversalis fascia. For multiple levels we use a
28 Minimally Invasive Anterior Column Reconstruction for Sagittal Plane Deformities
ab
Fig. 28.4 Intraoperative A-P fl uoroscopy. ( a ) The curved retractor can be visualized reaching almost entirely across to
the contralateral side ( b ) The intradiscal spreader is seen in the process of opening the disc space
279
single longitudinal skin incision with individual
transverse fascial incisions for each level
accessed. Serial dilators traverse the psoas muscle and are positioned over the junction of the
middle and posterior third of the disc space, using
directional electrophysiologic monitoring
(NV5®, NuVasive, Inc., San Diego, CA) to guide
dilator placement and minimize the risk of lumbar plexus motor nerve injury [ 37 , 38 ]. A retrac-
tor is placed (MaXcess®, NuVasive, Inc., San
Diego, CA) and secured by a table-mounted fl exible arm while a shim blade anchors the retractor
into the disc space [ 39 , 50 ].
An annulotomy and extensive discectomy are
then performed paying careful attention to endplate preparation and preservation. A curved custom retractor is then gently passed along the
anterior edge of the ALL and positioned between
the large vessels/sympathetic plexus and the ventral aspect of the disc (Fig. 28.4 ). The great ves-
sels are not visualized at this point, as that amount
of dissection would likely place the patient at
more risk than simply placing a 1–2 mm retractor. Using a custom disc blade and intradiscal distractor, the ALL is sectioned in a sequential
fashion, easing the curved retractor across to the
contralateral side of the disc space. Complete
ALL release is confi rmed when the adjacent VB
end plates are mobilized with minimal resistance
and there is an obvious “fi sh-mouth” opening of
the ventral disc space.
Once the end plates are prepared, an
appropriate- sized PEEK cage is selected
(CoRoent® XL-Hyperlordotic, NuVasive, Inc.,
San Diego, CA). These cages range from 8 to
18 mm in height × 22 mm in width × 50–60 mm
in length × 10°–30° lordosis and are packed with
allograft of the surgeon’s preference. The cages
are anchored to the adjacent VB with one or two
screws to prevent ventral migration into the peritoneal cavity and loss of indirect decompression
(Fig. 28.5 ).
28.7 Case Illustration
A 66-year-old male presented with severe back
pain radiating to the right leg with limited ability
to ambulate, with VAS and ODI scores of 22 and
54, respectively. Preoperative imaging showed a
thoracolumbar coronal Cobb angle of 54°, SVA
of 10 cm, LL of 23°, PI of 67°, PT of 34°, SS of
18°, and SL at L2–4 of 5°.
During stage 1, he underwent MIS lateral
interbody fusion from T12–L5 with ALR at
T12/L1, L2/3, and L3/4 with placement of
hyperlordotic PEEK cages, along with an L5/S1
anterior lumbar interbody fusion (ALIF). Stage
280
A. Deukmedjian and J.S. Uribe
Fig. 28.5 Sagittal CT scan with implanted hyperlordotic
cage. Image of the lumbar spine demonstrating a hyperlordotic cage at the L2/3 disc space, with transverse
screws traversing the vertebral body
2 consisted of T10–S1 posterior percutaneous
pedicle screw fi xation. Both procedures were
tolerated well and without complication, with a
total EBL of <100 cc. His VAS and ODI scores
improved to 16 and 30, respectively, and imaging revealed a thoracolumbar coronal Cobb
angle of 15°, SVA of 3 cm, LL of 50°, PI of 67°,
PT of 25°, SS of 40°, and SL at L2–4 of 25°
(Fig. 28.6 ).
Preop
Coronal Cobb angle 54 deg 15 deg
SVA 10 cm 3 cm
Sacral slope 18° 40°
Pelvic incidence 67° 67°
Pelvic tilt 34° 25°
Lumbar lordosis 23° 50°
Segmental lordosis 5° 25°
Postop
28.8 Osteotomy via the Lateral
Transpsoas Approach:
“Hybrid PSO/VCR”
28.8.1 Introduction
For all the reasons stated previously, including
morbidity of the posterior osteotomy as well as
technical challenges, there has been a drive for a
safer and less invasive way to do the osteotomy.
Although this subject is in its infancy, we propose
a hybrid technique, approaching from both lateral
and posterior when performing an osteotomy.
This is especially important at the more rostral
levels (T12–L2) due to the relative infl exibility in
mobilizing the neural structures. Another diffi culty with a posterior-only osteotomy is the
increased chance of pseudarthrosis at the osteotomy site and subsequent hardware failure. With a
hybrid PSO, manipulation of the neural elements
is minimized when resecting the PLL (posterior
longitudinal ligament) and making the wedge
osteotomy. The surgeon is also able to provide
interbody fusion at the corresponding rostral/caudal levels, reducing the risk of pseudarthrosis and
hardware failure.
28.8.2 Anatomic/Operative
Considerations
From the standpoint of the lateral approach,
the anatomy and technique is similar to that
described previously. The bony resection is that
of a lateral corpectomy, also described elsewhere in this volume. However, in our limited
experience, we have discovered thus far two
different variations in performing the lateral
osteotomy:
1. If the patient is fused above and below (e.g.,
Harrington rods, previous interbody fusions
like TLIF/XLIF/DLIF), then the retractor is
placed at the level of the vertebral body (VB)
and the wedge osteotomy is made with resec-
tion of the ipsilateral pedicle and PLL.
2. If the patient is not fused above or below, the
retractor is placed at those disc spaces and