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16 Thoracic Lateral Extracavitary Decompression and Fusion
Fig. 16.2 View following removal of the rib (Adapted from Rice et al. [15])
183
contralateral edges. Once all pathological tissue
has been removed, the posterior cortical rim can
be carefully removed by dissecting between the
posterior longitudinal ligament with a curette.
Once the cortical bone is removed, the posterior
longitudinal ligament should be removed to
expose the dura mater with careful inspection to
identify any remaining ventral compression on
the spinal cord. Any pathology identified should
be removed, avoiding any manipulation of the
spinal cord. If necessary, the resection of an additional adjacent rib may improve exposure and
allow for adjacent vertebral body decompression
in a similar manner.
Treatment of calcified central intervertebral
disc herniations generally does not require a full
corpectomy. Instead, a working cavity should be
created around the pathological disc space.
Beforehand, the lateral edge of the posterior longitudinal ligament should be identified to ensure
identification of the spinal canal. Once this
important anatomical landmark is confirmed, the
inferior endplate of the cranial vertebral level and
the superior endplate of the caudal vertebral level
can be drilled away. A thin rim of cortical bone
should be maintained along the posterior aspect
of the vertebral bodies. Then a curette may be
used to create a dissection plane between the posterior longitudinal ligament and the remaining
cortex. This can then be pushed into the superior
and inferior resection cavities above and below
the disc. Then the remaining calcified disc can be
pushed inferiorly and removed to relieve the
compressive forces on the spinal cord without
requiring undue manipulation.
Spinal Reconstruction
Generally, in all cases where the decompressive
steps involved all three columns of the spinal column, internal fusion and fixation will be needed
to ensure the maintenance of biomechanical stability. Allograft, autograft, or synthetic structural
cages are all options for reconstruction of the
defect (Fig. 16.3). The choice of graft material is
typically dictated by the nature of the pathology.
The anterior graft should be supported with posterior pedicle screw instrumentation. This is typically done with bilateral pedicle screws inserted
into at least two levels above and two levels
below the level of decompression with joining
posterior rods. If there is concern for instability
and progressive development of deformity during
the decompressive stages of the operation, the
pedicle screws may be placed following the initial stages of boney exposure and the contralateral rod placed to maintain alignment. The
ipsilateral rod will then be placed following the
decompression and ventral reconstruction. If
there is a preexisting deformity requiring reduction to attain normal alignment, a rod may be
placed through the contralateral pedicle screws to
maintain temporary positioning. Then following
decompression and ventral reconstruction, the
ipsilateral rod may be placed and held loosely in
place by blocker caps. The blocker caps on the
contralateral rod may then be loosened, and the
184
Fig. 16.3 Ventral reconstruction following decompression (Adapted from Scheer et al. [16])
C.D. Witiw and R.G. Fessler
deformity may be corrected using sequential
reduction maneuvers and blocker fixation until
appropriate alignment is achieved. Final blocker
tightening is then used to maintain the
alignment.
Minimally Invasive Lateral Extracavitary Approach
Substantial tissue dissection is required for the
traditional open LECA, and this has compelled
efforts to reduce the invasiveness of the approach.
The initial description of a minimally invasive
lateral extracavitary approach (MI-LECA) was
presented by Kim et al. in 2009 [12]. The steps
involved with the decompression are quite similar to the traditional approach; however, there are
important differences in the surgical exposure
and spinal reconstruction.
Initial exposure may be accomplished by
either a small paramedian cutaneous incision to
accommodate the tubular dilator or one longer
midline cutaneous incision to the level of the tho-
for the longer midline incision. This obviates the
need for multiple stab incisions for insertion of
the percutaneous posterior instrumentation, and
we have found that the larger cutaneous incision
has minimal impact on postoperative pain and
recovery. After cutaneous exposure, an initial
dilator is docked on the lateral facet of the pathological level. Sequential tubular dilators are
inserted, and once sufficient nontraumatic muscular dilatation is achieved, an expandable tubular retractor is inserted and fixed in place by a
table-mounted adjustable arm. The lamina, facet,
transverse process, costovertebral and costotransverse joints, and the rib head are exposed with
subperiosteal dissection through the tubular
retractor using electrocautery in a similar manner
to the traditional open approach.
The removal of the rib head and proximal segment of the rib allows for improved ventromedial
visualization. During rib removal, blunt dissection of the ventral and inferior aspect of the rib
can be performed with a Penfield #1 which helps
avoid injury to the underlying pleura and neurovascular bundle. The rib is then resected distally
with a Leksell rongeur. This is followed by the
pediculectomy as previously described which
affords visualization of the spinal canal and identification of the posterior longitudinal ligament
performed. The remaining steps of spinal cord
decompression are similar to the traditional open
approach, and the spinal column reconstruction
may be performed by inserting the anterior graft
through the expandable tubular retractor into
position (Fig. 16.5a, b).
Following anterior decompression and reconstruction, posterior pedicle screw instrumentation is inserted percutaneously. Intraoperative
fluoroscopy is used to dock a Jamshidi needle at
the junction of the lateral margin of the superior
facet and midpoint of the transverse process.
Next, a Kirschner wire (K-wire) is drilled in
2 cm, and the Jamshidi needle is removed. The
K-wire is then advanced into the vertebral body
using lateral fluoroscopy to visualize depth
16.6a), and sequential tubular dilators
(Fig.
(Fig.
16.6b) are used to create a nontraumatic
pathway through overlying muscle to tap the pedicle and insert the pedicle screw (Fig.
16.6c), and
16 Thoracic Lateral Extracavitary Decompression and Fusion
Fig. 16.4 Cutaneous
exposure with the
thoracodorsal fascia
intact for a minimally
invasive lateral
extracavitary approach.
This affords sufficient
exposure for muscular
dilatation for ventral
decompression and
fusion, as well as
insertion of posterior
instrumentation without
requiring multiple
cutaneous incisions
185
Fig. 16.5 Minimally
invasive insertion of an
expandable titanium
cage for reconstruction
of the thoracic spinal
column after single level
corpectomy. (a) Lateral
fluoroscopic image
showing the positioning
of the expandable
tubular retractor (white
arrow) and the
expandable titanium
cage. (b) Intraoperative
photograph following
insertion of the cage
from the surgeon’s
perspective looking
down the expandable
tubular retractor
186
C.D. Witiw and R.G. Fessler
Fig. 16.6 Posterior percutaneous pedicle screw instrumentation. (a) Lateral intraoperative fluoroscopic image
of the K-wires inserted into the thoracic vertebral bodies
this step of the operation is completed with the
insertion of the posterior rods.
Transpedicular or Costotransversectomy Approaches
In cases where the patient may not require or tolerate the lateral exposure afforded by the LECA,
then a transpedicular approach or costotransversectomy may be considered (Fig. 16.7). The primary difference between the LECA and the
costotransversectomy is the lateral extent of rib
resection. The surgeon should be aware that the
costotransversectomy will afford less ventromedial visualization, thus making ventral decompression and spinal column resection more
challenging. With the transpedicular approach,
the costovertebral articulation complex is left
intact. This affords much less ventromedial visualization and will make insertion of a graft for
ventral spinal column reconstruction a challenge
and often not possible; however, a bilateral transpedicular approach will often be sufficient to
relieve ventral compression on the thoracic spinal cord and is particularly useful in metastatic
tumor cases when separation of the tumor margin
and dura mater is desired prior to radiotherapy.
Maintain artist signiture. A midline cutaneous
incision is sufficient to provide exposure for both
the costotransversectomy and transpedicular
approach. Paraspinal musculature should be dissected from the posterior osseous elements along a
subperiosteal plane and then retracted in bulk laterally using a self-retaining retractor. Visualization
cranial to the lesion; (b) tubular dilatators; (c) insertion of
the pedicle screws through the tubular dilators
of the transverse processes is sufficient for a transpedicular approach; however, if a costotransversectomy is planned, then the dissection should be
carried further laterally to identify the angle of the
rib and the costotransverse joint. When performing a costotransversectomy, the steps of resecting
the transverse process, costovertebral articulation
complex, laminofacet, and ipsilateral pedicle will
proceed in a manner similar to that of the
LECA. When performing a transpedicular
approach, the transverse process should be
removed with a Leksell rongeur, and a laminectomy should be performed to permit palpation of
the medial wall of the pedicle. The ipsilateral laminofacet can then be removed with an osteotome,
and a high-speed burr can be used to perform the
pediculectomy using an inside-out method as previously described which will afford access to the
ventrally located compressive pathology.
Lateral Parascapular Extrapleural Approach
The upper thoracic vertebrae are difficult to
approach surgically because of the parascapular
shoulder musculature and the narrowing of the
thoracic cage to reach the thoracic inlet. The lateral parascapular extrapleural approach provides
a similar ventral exposure as the traditional
LECA but should be used for neural decompression and vertebral reconstruction at T1–T4. The
following description outlines the technical
details of this exposure as it differs from the traditional open LECA performed at the lower
16 Thoracic Lateral Extracavitary Decompression and Fusion
(Fig. 16.8a). This muscular mobilization will
induce lateral movement of the scapula and
increase the lateral exposure to the spinal column. Next, the splenius cervicis and erector spinae muscles are dissected from the spinous
processes, and this muscular mass is retracted
medially toward the contralateral side
(Fig. 16.8b).
is generally provided by removing the rib at the
level of interest along with the rib below. This is
accomplished using the technique outlined in
the section describing the open LECA. The rib
should be sectioned laterally at the angle of the
rib and then disarticulated from the costotransverse and costovertebral joints after subperiosteal dissection and careful protection of the
neurovascular bundle running along the underside of the rib (Fig. 16.8c). The sympathetic
chain, located on the lateral vertebral surface,
should be identified and the rami communicantes transected.
sion and vertebral column reconstruction proceed
in a manner similar to that described previously
in the section on open LECA (Fig. 16.8d). Wound
closure should proceed systematically to ensure
Fig. 16.7 Artist rendition of the exposure afforded by
each of the three posterolateral approaches to the thoracic
spine: (a) transpedicular approach, (b) costotransversectomy, and (c) lateral extracavitary approach (Adapted
from Steinmetz et al. [17])
appropriate layered re-approximation. The splenius cervicis and erector spinae muscles are
returned from their retracted positioning on the
contralateral side, and the trapezius and rhomboid muscles are returned from their lateral posi-
tioning. The deep and superficial facial layers are
thoracic levels; however, the decompression and
vertebral column reconstruction are largely simi-
re-approximated to ensure obliteration of any
potential dead space.
lar to the open LECA.
A midline incision down to the deep facial
plane is made extending from three spinous pro-
Illustrative Case
cesses above and below the level of the level of
the lesion. This should be curved lateral to the
scapular line on the side of approach. The incision is extended down to the spinous processes,
and the trapezius and rhomboid muscles are dissected free in the subperiosteal plane. Blunt finger dissection is used to free the muscle layers. A
myocutaneous flap that incorporates the skin,
rhomboid, and trapezius muscles is then reflected
laterally toward the medial boarder of the scapula
While the primary indication of the LECA is for
ventral decompression of the spinal cord, it also
may be used to provide spinal column recon-
struction in instances of trauma where the pri-
mary issue is painful deformity rather than spinal
cord compression. In this instance, a 29-year-old
female presented with a 2-year history of pro-
gressively worsening mid-thoracic back pain that
began after a motor vehicle collision where she
187
Sufficient exposure to the level of the lesion
The stages of lateral and ventral decompres-
188
C.D. Witiw and R.G. Fessler
Retracted
Paraspinal
Muscles
Spinous
Process
Costotransverse
Articulation
lliocostalis Thoracis
Muscle
Longissimus Thoracis
Muscle
Spinalis Thoracis
Muscle
Latissimus Dorsi
Muscle
Second Rib
First Rib
Trapezius Muscle
Ligated Thoracic
Nerve Roots
Transected Rami
Communicantes
Graft for anterior
vertebral column
Ganglion of
Sympathetic Chain
Lesion of Vertebral Body
5])
reconstruction
(c) view following the removal of the ribs; (d) view following vertebral column
reconstruction (Adapted from Fessler et al. [
Ganglion of Thoracic
ab
Splenius Cervicis
Muscle
Rhomboid Minor
Muscle
Rhomboid Major
Muscle
Nerve Root
cd
Dura
Medial Edge
of Lamina
Pleura
Lateral
Margin of
Resected Rib
Fig. 16.8 Surgical stages of the lateral parascapular extrapleural approach to the
upper thoracic spine. (a) Lateral reflection of the myocutaneous flap incorporating
the trapezius and rhomboid muscles; (b) medial reflection of the paraspinal muscles;
16 Thoracic Lateral Extracavitary Decompression and Fusion
189
sustained a T10 compression fracture with
subsequent progressive kyphotic deformity
16.9a).
(Fig.
Surgical intervention was planned to restore
alignment at the affected segment. An MI-LECA
as previously described was used. A partial anterior corpectomy at T10 was performed through
the tubular retractor (Fig.
16.9b). After bony
resection, a trial cage was inserted to determine
the appropriate size (Fig. 16.9c), and this was followed by inserting an expandable titanium cage
to correct the segmental deformity (Fig. 16.9d)
which was followed by posterior instrumentation
at the final stage. Postoperative standing
radiographs demonstrated restoration of spinal
alignment (Fig. 16.10a, b), and the patient’s
debilitating pain symptomatology was relieved.
Technical Pearls
Several important technical surgical considerations were described during the technical
descriptions of the preceding section; however,
there are some additional factors that all surgeons
performing posterolateral access to the thoracic
spine should be aware of. We have outlined these
by each stage of the operation.
Fig. 16.9 Intraoperative fluoroscopic images. (a) Lateral
view demonstrating positioning of the tubular retractor
and segmental kyphotic deformity at T10 from a chronic
traumatic compression fracture: (b) Anteroposterior view
demonstrating the positioning of the tubular retractor lat-
eral to the affected level; (c) Lateral view with insertion of
the trial spacer following partial anterior corpectomy at
T10; (d) Lateral view with insertion to the expandable
titanium cage
190
Fig. 16.10 Postoperative
standing plain film
radiographs. (a) Lateral
view demonstrating
restoration of segmental
alignment with an
interbody expandable
cage at T10 and pedicle
screw instrumentation
two levels above and
below providing posterior
support; (b)
Anteroposterior view
demonstrating the same
construct
C.D. Witiw and R.G. Fessler
Exposure Stage
• During intraoperative localization, the ana-
tomic relationship between the vertebral body
and intervertebral disc space is important. The
rib belongs to the inferior level of the disc
space of interest. For example, the seventh rib
articulates with the transverse process and
vertebral body of T7 and overlies the T6/T7
disc space. This recognition is critical to
ensure appropriate exposure.
• Similarly, it is necessary to accurately identify
where the transverse process articulates with
the proximal rib. Aggressive dissection with
electrocautery in this area may cause an unintended pleural breach or an injury to the neurovascular bundle running along the underside
of the rib.
Ventral Decompression Stage
• To protect the thoracic vascular structures, the
anterior cortex of the vertebral body should be
left intact whenever possible. The only
exception to this is cases where the surgery is
being performed for tumor resection.
• When decompression is required for a calcified central intervertebral disc herniation, we
have found it helpful to drill away 2 or 3 mm
of the pedicle at the caudal level to improve
medial visualization and enhance surgical
access to the herniation without requiring
undue manipulation of the spinal cord.
Ventral Instrumentation Stage
• It is necessary to ensure that the vertebral
body endplates adjacent to the site of
decompression are sufficiently exposed to
allow for optimal fusion.
• Care should be taken to remove the anterior
and posterior lips of the endplates to avoid a
central separation between the endplates and
the graft.
• Conversely, excessive iatrogenic destruction
of the vertebral body endplates should be
16 Thoracic Lateral Extracavitary Decompression and Fusion
191
avoided to mitigate the risk of graft subsidence into the cancellous bone.
Posterior Instrumentation Stage
• An appreciation of the changing anatomical
orientation of the thoracic pedicles moving
caudally in the thoracic spine is important to
avoid misplaced instrumentation. The thoracic
pedicles are angled most medially in the upper
thoracic spine and then become increasingly
more anteriorly oriented moving caudally
down to T12.
• When placing percutaneous pedicle screws,
unintended anterior migration of the K-wire
through the vertebral body represents a potential source of complications. An assistant
should fix the wire with an instrument, particularly when tapping the pedicle.
• K-wire fracture is another risk during percutaneous pedicle screw insertion. It is important
to maintain a consistent parallel trajectory of
the K-wire with the pedicle as a loss of alignment may lead to a fracture of the K-wire.
Pulmonary Complications
While one of the primary advantages of the
LECA is the theoretical avoidance of the pulmonary complications associated with an intracavitary anterior approach, there is still a notable risk
of pulmonary-related adverse events [
best approach for avoidance is to stay extrapleural. Meticulous dissection of the pleura from the
rib and rib head, as well as gentle retraction of the
lung, will serve to help avoid an unintentional
breach of the pleural membrane. Prior to wound
closure, the operative field should be filled with
saline irrigation and observed for the presence of
an air leak. Identified pleural breaches may be
repaired primarily with nonabsorbable interrupted sutures. If the pleural breach cannot be
identified or repaired and the air leak persists
intraoperatively, then a 24-French thoracostomy
tube should be placed and tunneled to a percutaneous exit site inferior to the incision. In the
instance of a significant pleural fluid collection
diagnosed postoperatively, it is best to treat this
with tube thoracostomy because initial thoracentesis has been found frequently to be ineffective
in preventing recurrence [14].
18]. The
Complications and Strategies for Avoidance
The LECA is technically challenging, often the
interventions are prolonged, and there is a notable potential for adverse events. Resnick et al.
reported a 55% incidence of morbidity from a
series of 33 patients undergoing a traditional
open LECA for thoracic trauma in the acute setting. Their mean surgical time was approximately
7.5 h and a mean blood loss of just over 3 l. The
most common complications were pleural fluid
collections, pneumonia, and surgical wound
infections. Moreover, with any large exposure to
the spine, the potential for cutaneous cerebrospinal fluid leaks is ever present. A number of strategies may be employed to mitigate these risks, and
these are reviewed in this section.
Excessive Bleeding
The LECA is often employed when substantial
decompression is needed. As such, there is a
notable risk of blood loss, and it is critical to
ensure that the abdomen is decompressed when
the patient is placed in the prone position to
reduce venous stasis and avoidable intraoperative
bleeding.
When the approach is used for extradural
tumors of the spinal column, a preoperative tissue
diagnosis will allow for the recognition of highly
vascularized pathological lesion types. In such
cases, preoperative angiographic embolization
may be undertaken to reduce the risk of intraoperative blood loss. Even with preoperative embolization, however, tumor bleeding can still be
192
C.D. Witiw and R.G. Fessler
quite significant. Most often the source of hemorrhage is from the tumor bed, and this is best managed with complete removal of all visible tumors
whenever possible. Bleeding should not be
treated with bone wax, as this may limit osteogenesis and predispose to pseudarthrosis [18].
Vigilance for sites of epidural bleeding is important, and hemostasis should be attained with
bipolar coagulation. Identified epidural vessels
may be coagulated and then sharply dissected
when needed during the stages of decompression.
Hemostatic gelatin or other packing agents may
also be employed as needed while being careful
not to apply any force on the spinal cord.
Wound Infections
With large, traditional open exposures, the risk
for postoperative wound infection is high. This is
further exacerbated by the presence of hardware
and, in cases of malignancy, wound breakdown
reasons, meticulous multilayer wound closure is
critical, and the surgical field should always be
copiously irrigated. A substantial body of evidence has now emerged to support the use of vancomycin powder as an adjunct to reduce infection,
and we support its use [19, 20]. Furthermore, the
use of minimally invasive technique may represent an opportunity to lower the incidence of
infection [
21, 22].
Cutaneous Cerebrospinal Fluid Leaks
durotomies may necessitate cerebrospinal fluid
(CSF) diversion with the use of a percutaneously
inserted lumbar intrathecal catheter. As with
wound infections, minimally invasive techniques
may also represent a means of lowering the incidence of postoperative cutaneous CSF leaks [23].
Conclusion
The LECA represents a well-accepted surgical
technique to address ventral compressive pathology in the thoracic spine. The primary advantages are the ability to address the ventral
pathology while supplementing the spinal column reconstruction with posterior instrumentation, all through a single incision without the
need for patient repositioning. Modifications to
the technique such as the LEPA for the upper thoracic spine as well as selection of a costotransversectomy or transpedicular approach may be
employed as appropriate. However, these procedures are technically challenging and should generally be reserved for those with substantial
familiarity with spinal interventions. There is a
notable risk of surgical complications with any of
these approaches, but the techniques outlined
within this chapter should serve to reduce the
risk. Advancements made in minimally invasive
techniques and technologies have lowered the
soft tissue destruction required, and it is likely
that the posterolateral approach to the thoracic
spine will continue to serve as a mainstay in the
spinal surgeon’s armamentarium.
An incidental durotomy may occur during
decompression along the thecal sac. At other
times, tumor erosion may lead to sections of
absent dura mater. In instances of a discrete dural
breach, primary repair should be attempted with
a nonabsorbable 4-0 suture. However, in certain
cases, this may not be possible. We suggest these
should be managed with a synthetic dural patch
onlay and supplemented with fibrin glue. The
patient should be maintained on strict fully supine
bedrest for 24 h following the surgery for small
breaches in the dura; however, at times, larger
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