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A, B
Figure 33–1
Preoperative standing anteroposterior (AP) (A)
and lateral (B) x-rays of the spine.
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160
Figure 33–2
Intraoperative radiograph with guide pins.
SECTION II THE THORACIC SPINE
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Decortication performed
at presumed pedicle
entry point
Junction of transverse
process and lamina
Decorticated site
Pin
Pedicle entry
point
A
C
Drill
Screw
Figure 33–3
(A) Decortication is performed at the presumed pedicle entry points. In the thoracic spine, it is located at the junction of the superior margin of the transverse process and
the lamina. (B) Guide pins are inserted at the presumed entry site. They are inserted shallowly, just enough to hold in the exposed cancellous bone. (C) Deep drilling is performed. For maximum holding power, the diameter of the drill should be equal to that of the minor diameter of the screw inserted. (D) Screw is inserted gently into the pre-
pared hole.
B
D
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33 POSTERIOR SCOLIOSIS CORRECTION: PEDICLE SCREWS
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6 mm
22°
A
3 mm
22°
22°
C
B
D
Figure 33–4
(A) On the concave side of the lowermost vertebra, the ideal entry point is 6 mm inferior and 3 mm lateral to the guide pin. (B) The ideal direction is 22 degrees more caudal
than the guide pin. (C,D) The pedicle is entered through the determined entry point following the direction determined.
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SECTION II THE THORACIC SPINE
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A
B
C
Figure 33–5
(A) A rod contoured to the normal sagittal contour of the instrumented segment is inserted to the concave side. (B) The rod is derotated 90 degrees with clamp. (C) After
locking the concave rod in the corrected position, the convex rod is inserted in situ and locked. Then the two rods are connected by transverse links.
A, B
Eurostile
Figure 33–6
Postoperative AP (A) and lateral (B) x-rays showing correction of the
deformity and restored spinal balance.
33 POSTERIOR SCOLIOSIS CORRECTION: PEDICLE SCREWS
163
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tion. Screws are inserted on every segment on the correction sides and
every second or third on the support sides.
Correction side (concave in thoracic, convex in lumbar) rod insertion:
Following the insertion of the screws on both the concave and the convex
sides, a rod contoured to have a slight exaggeration of the normal sagittal
contour of the instrumented segment is inserted into the correction side
(Fig. 33–5A). Insertion of the rod may be difficult when there is large discrepancy between the contour of the vertebral column and the rod. This
may be facilitated by using rod introducers or sequentially closing the
screw caps while rotating the rod to fit the contour of the vertebral column.
For long curves that span both the thoracic and the lumbar region, either a
long rod spanning the entire correction side or shorter rods spanning each
of the curves may be used. For a double thoracic curve, separate correction
of each curve is carried out with short rods on the respective concave sides.
When the plan is to perform separate correction of individual structural
curves, remove a pedicle screw at the junction of the rods to make room for
rod connectors. Following the rod insertion, the eye bolts are inserted
loosely over the screws.
Rod derotation: Using clamps or rod holders, the correction rod is rotated 90 degrees to transform the scoliosis into a kyphosis and/or a lordosis
depending on the region instrumented to restore the sagittal profile and
locked in corrected position (Fig. 33–5B). Correction of the deformity is
performed solely by derotation without any additional compression or distraction. As considerable straightening of the contoured rod occurs during
the process of derotation, it is advantageous to use large-bore stiff rods with
exaggeration of the normal sagittal profile. When two or more rods are used
on one side, they are to be connected by means of a connector prior to rod
rotation maneuver.
Support side rod insertion: As the rod is just supportive, the rod is bent
conforming to the shape of the corrected curve and placed in situ without
forceful manipulation. In double thoracic curves using a four-rod correction technique, support rods are connected to the correction rods by means
of connectors.
Transverse connection: Two transverse connectors are used in the pro-
ximal and distal part of the longitudinal members to enhance the torsional
stiffness of the pedicle screw construct (Fig. 33–5C).
Decortication and bone graft: After meticulous decortication, a generous bone graft is performed. In selective thoracic fusions, local bone mixed
with allograft results in satisfactory fusion. In fusions extending into midand lower lumbar spine, use of autogenous iliac bone graft is recommended (Fig. 33−6).
Instrumentation Tips
1. Top-loading implants are usually easier to handle than the side-attach-
ing implants.
2. Screws with an inner tightening nut are easier to use than the system
with an outer nut and reduce the chance of inadvertent facet joint injury.
3. Titanium screws are better than the stainless steel as they allow better
postoperative evaluation with computed tomography (CT) or MRI.
4. Screws with long flanges (long arm screws) may facilitate the surgery
when the vertebra to rod method has to be used to connect the rod to
the screws.
of the instrumented segment using the vertebra-to-rod or cantilever
method prior to the rotation maneuver.
Thoracic hyperkyphosis: The effect of deformity correction with rod rotation maneuver is reduced in the presence of thoracic hyperkyphosis. In
this special situation, the vertebra-to-rod technique bringing the vertebral
column to the contoured rod is preferable. Long-arm reduction screws are
particularly suitable for this procedure.
Rod contouring: As considerable straightening of the rod occurs during
the process of rod rotation, slight exaggeration of the desired sagittal profile is preferable, especially for the correction of thoracic hypokyphosis.
Additional compression or distraction: Deformity correction by pedicle
screw instrumentation is effected by spontaneous relocation of the instrumented vertebrae under anterior/posterior and medial translation force.
Addition of compression or distraction preloads the disc spaces and
hinders the relocation, and if applied at the end of the construct, may cause
wedging of the adjacent discs.
Number of screws: Reducing the number of screws on the correction
sides significantly increases the stress concentration on individual screws
and results in fixation failure during the derotation maneuver.
Complications of Instrumentation
Screw misplacement: Misplaced screws may cause neurologic, vascular,
major visceral injuries, dural tears, and delayed epidural hematoma. Strict
adherence to sound insertion technique is mandatory to avoid these complications. Various methods (e.g., intraoperative roentgenograms, intraoperative evoked electromyogram, intraosseous endoscopy, saline challenge test etc.) may be utilized to confirm the pilot holes and the position of
the pedicle screws.
Neurologic complications: These may have several causes (e.g., screw
misplacement, overdistraction of the instrumented segment, delayed
epidural hematoma). If postoperative neurologic deficit is detected, CT or
MRI evaluation is necessary. We prefer MRI as it may provide additional
information about the status of the soft tissue and the neural elements.
Pedicle fractures: These are caused by drill/pedicle or screw/pedicle
mismatch. Making the screw hole as large as the minor diameter of the inserted screw may prevent the complication. In young patients with hard
cancellous bone, tapping of the pedicles prior to screw insertion may reduce the complication.
Screw pullouts and vertebral body fractures: These are most commonly
due to an inadequate number of screws and an overzealous attempt at correcting the deformity with a rod that does not conform to the contour of the
vertebral column. Segmentalizing the screw fixation on the correction side
and generous contouring of the rod may effectively prevent these complications.
Screw/rod breakage and uncoupling: When detected more than 6
months after the operation, this indicates the presence of nonunion. If a
significant loss of initial correction is noted, it is best revised by a repeat fusion with removal of the broken implants.
Postoperative Care
Chest x-rays and simple abdomen are checked in the recovery room to confirm the absence of major vascular and visceral injuries related to screw
placement.
Pitfalls
Double thoracic curve: Due to improved correction of the instrumented
curve, unnoticed upper thoracic curves may cause postoperative shoulder
and neck asymmetry. When using pedicle screw instrumentation, an upper
thoracic curve 쏜 25 degrees should also be fused when the shoulder on the
convex side of the upper thoracic curve is level or higher than the opposite
side.
Thoracolumbar curve: Contouring the correction rod to conform the
lateral spinal curvature results in reversal of the sagittal contour in either
the thoracic or the lumbar spine depending on the direction of the rod rotation. For this type of curvature, the rod is connected to the screws by bringing the vertebral column to the rod contoured to the normal sagittal profile
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SECTION II THE THORACIC SPINE
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Suggested Readings
Suk SI, Lee CK, Kim WJ, Chung YJ, Park YB. Segmental pedicle screw fixa-
tion in the treatment of thoracic idiopathic scoliosis. Spine
1995;20:1399–1405.
Suk SI, Kim WJ. Pedicle screw fixation for thoracic scoliosis. In: Brown
CW, ed. Spinal Instrumentation Techniques. Vol. 2. Milwaukee:
Scoliosis Research Society; 1998.
Suk SI, Kim WJ, Kim JH, Lee SM. Restoration of thoracic kyphosis in hy-
pokyphotic spine: a comparison between multiple hook and segmental
pedicle screw fixation in adolescent idiopathic scoliosis. J Spinal Disord 1999;12:489–495.
34
Anterior Thoracoscopic Release for
Spinal Deformity
Mark Weidenbaum and Mladen Djurasovic
Goals of Surgical Treatment
To increase curve correction and augment fusion in thoracic deformities by
anterior discectomy and anterior longitudinal ligament release prior to instrumentation.
Diagnosis
Thoracic scoliosis is a three-dimensional deformity involving hypokyphosis in the sagittal plane, lateral deviation in the coronal plane, and verte-
bral rotation in the axial plane. The curve apex lies between T2 and the
T11–12 disc. Kyphosis involves deformity primarily in the sagittal plane.
The diagnosis of either scoliosis or kyphosis is made by physical examination (shoulder or pelvic asymmetry, rib prominence, gross coronal or sagittal plane deformity, etc.) as well as with standing 36-inch posteroanterior
(PA) and lateral scoliosis radiographs.
Indications (Similar to Open Anterior Releases)
1. Rigid scoliosis 쏜 75 degrees (residual curve on bending 쏜 50 degrees)
2. Scheuermann’s kyphosis 쏜 70 to 75 degrees
3. Scoliosis 쏜 50 degrees in skeletally immature patients at risk for crank-
shafting with posterior fusion alone
4. Neuromuscular, congenital, and metabolic deformities requiring ante-
rior arthrodesis
5. Neurofibromatosis
6. Painful/progressive adult curves
Contraindications
1. Inability to tolerate single lung ventilation (severe respiratory insuffi-
ciency, pulmonary hypertension)
2. Extensive pleural adhesions (e.g., empyema, previous cardiac/thoracic
procedure)
3. High airway pressures with positive pressure ventilation
4. Age/size limitations in the pediatric age group depending on tracheal/
main stem bronchus size and available endoscopic equipment
Advantages
1. Less postoperative pain than with open thoracotomy
2. Less blood loss
3. Better visualization of thoracic anatomy (magnification, illumination)
4. Fewer respiratory problems (less postoperative pain and chest wall
splinting)
5. Minimal shoulder girdle dysfunction (less muscle transection)
6. Better cosmesis
7. Shorter hospitalization, possibly leading to lower costs
Disadvantages
1. Steep learning curve
2. Need for skilled endoscopic thoracic surgeon for early cases
3. Longer initial operative times until surgical team is sufficiently ex-
perienced (ultimately operative times will be reduced)
4. Extensive equipment needs (monitors, multichip camera, scopes, in-
strumentation)
Procedure
Preoperative Planning and Setup
1. All rigid levels should be released. Optimal release addresses enough
levels to restore harmonious three-dimensional spine contour.
2. Working with a thoracic surgeon experienced with thoracoscopic tech-
niques is strongly recommended.
3. Monitors on both sides of the table allow best visualization.
4. Single lung ventilation is mandatory.
5. Position the patient in the lateral decubitus position (convex side up),
with the table flexed (i.e., dropping hips and lower extremities) to increase intercostal distances. Securely position to allow tilting or Trendelenburg/reverse Trendelenburg positioning. Gently flex the
shoulder to allow proximal portal placement (Fig. 34–1).
6. Prep and drape the chest widely in case of need for conversion to open
thoracotomy.
7. Manage venous and arterial access, spinal cord monitoring, as well as
fluids and antibiotics as in an open procedure.
Portals
1. The first portal is generally placed at the sixth/seventh intercostal
space (to avoid the diaphragm) between the anterior and posterior axillary lines. After skin incision over the rib, the subcutaneous tissue and
chest wall musculature is spread apart with a hemostat clamp introduced above the rib to allow entry into the pleural space (Fig. 34–2). Be
sure that hemostasis is complete so blood does not drip from the portal. Digital exploration ensures that no pleural adhesions will prevent
subsequent lung atelectasis. Either a rigid or a flexible port is then introduced, followed by a 0- or 30-degree thoracoscope attached to a
three-chip camera. The 0-degree scope is best for looking “head on,”
while the 30-degree scope is better for looking above/below.
2. Additional portals are established similarly under direct thoracoscopic vision, usually at the third, eighth, and 11th intercostal spaces.
A variety of different portal arrangements can be used depending on
body habitus, level of curve apex, and number of levels to be
addressed. Proper portal placement prevents instrument “fencing”
where the long endoscopic instruments interfere with each other.
3. Because of the length of spine involved, at least three or four ports are
needed: one for the camera/scope, one for retraction, and one for the
working instrument. On occasion it is possible to place more than one
instrument through a given portal.
Approach and Releases
1. Once successful single lung ventilation has resulted in resorptive
atelectasis, the deflated lung can be retracted through a second portal
site, usually at the eighth or ninth intercostal space. The deflated lung
often stays down and requires minimal retraction. Trendelenburg positioning can help the lung fall away from the operative field when
working on the lower thoracic spine, whereas reverse Trendelenburg
can help for the upper thoracic spine. For the mid-thoracic spine,
slight airplaning of the table toward the ventral side can help.
2. The ribs are counted, beginning from the cephalad direction. The
segmental vessels are usually easily identified. They run in the “valleys” or low points of the concavities of the vertebral bodies. The discs
correspond to the “peaks” between the vessels.
3. A spinal needle or radiopaque marker is placed in the disc and a lateral
radiograph taken to obtain confirmation of the appropriate level.
4. Orientation must be retained at all times. It is easy to become confused
by the magnification (15×), the three-dimensional deformity of the
spine, as well as image rotation on the monitors due to positioning and
scope angulation/rotation. Aligning the spine so it appears horizontal
in the monitor (like the patient) may be helpful. Moving in/out with
the scope helps with depth perception and overall perspective. Fogging may be an issue early in the case, and can be addressed with
frequent irrigation. Once the scope warms up to body temperature, fogging is much less.
5. With the lung retracted, the parietal pleura is gently lifted with an endoscopic grasper and incised with a hook electrocautery, a harmonic
scalpel, or a scissor. This can be done either transversely or longitudinally at the mid-disc level. (A longitudinal incision may prevent injury
to the thoracic duct when working in the lower thoracic region.) A
peanut or Kittner is then used to clear the disc around to the other side
(up to ∼ 120-degree arc). Never try to reach around blindly or work
without direct visualization.
6. The segmental vessels can often be preserved. However, vessel ligation
may be necessary to reach the lateral and posterolateral annulus. Vessel ligation starts with widely clearing the parietal pleura for optimum
exposure. Efforts to get under or around the vessels should be avoided.
Rather, the vessels are gently “massaged” with a bipolar electrocautery,
divided with the harmonic scalpel, or ligated with endoscopic vessel
clips. Bleeding from tiny branches may appear worse than it is due to
magnification and can be controlled with direct pressure (peanut), or
localized application of thrombin-soaked Gelfoam.
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34 ANTERIOR THORACOSCOPIC RELEASE FOR SPINAL DEFORMITY
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Figure 34–1
Position of the patient in the lateral decubitus position to increase intercostal distances. Shoulder is flexed to
allow proximal portal placement.
Portals
Rib1
2
3
4
5
12
11
10
6
7
8
9
Anterior longitudinal
ligament
Rib
head
Azygos vein
Esophagus
Lung
Disc
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Figure 34–2
Incision and exposure of the portal.
SECTION II THE THORACIC SPINE
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Intercostal
nerve
Sympathetic trunk
Ligated intercostal vein
and artery
Ao
BA
Rotate
elevator
Eso
A
Annulus, nucleus, and anterior
longitudinal ligament removed
L
End plates
removed
Rotate elevator in disc space
Figure 34–3
Cobb elevator placed in disc space after release (A), and with Cobb elevator rotated (B), demonstrating release at this level. (See Color Plates 34–3A,B.)
B
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34 ANTERIOR THORACOSCOPIC RELEASE FOR SPINAL DEFORMITY
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7. The anterior longitudinal ligament (ALL), nucleus, and annulus are removed with curets and rongeurs (Kerrison, pituitary). Many long nonendoscopic instruments fit through the ports (check first) and allow
the surgeon the comfort of their familiar “feel.” The relation of rongeur
length to the end plates helps guide the depth of resection to prevent
penetration of the posterior longitudinal ligament (PLL) and dural injury. The exposed end plates are then gently scraped down (without
gouging or digging in deeply) to a fresh bleeding surface.
8. The adequacy of release is assessed by manually pushing on the spine
posteriorly and by rotating an elevator in the disc space (Fig. 34–3). Occasionally rib head excision is required to increase mobility. This can
be done under direct visualization with a rongeur, a curet, or a shaver.
The disc space is then irrigated and packed with Gelfoam.
9. One of the portal incisions can be lengthened by 2 cm to allow open rib
harvest with minimal difficulty. The incision can easily be retracted to
allow substantial internal rib graft harvest. Alternatively, rib graft can
be harvested endoscopically by internal thoracoplasty. The harvested
bone is then cut up and gently tamped into the prepared disc spaces.
10. Five to eight levels are usually addressed. Working from the ends of the
curve toward the apex minimizes “trickle down” bleeding that can interfere with visualization. The diaphragm must be retracted to reach
T11.
11. The musculofascial, subcutaneous, and subcuticular layers of each
portal are meticulously closed.
Postoperative Care
1. Routine chest tube management (placed in one of the portals)
2. Bracing according to subsequent fixation procedure
3. Immediate ambulation
Pitfalls and Complications
Preoperative
1. Incorrect level selection
2. Poor patient selection (see above)
3. Inadequate surgeon training: animal lab training and observation of
several cases recommended
4. Incomplete operating room (OR) preparation: nursing/anesthesia/OR
team must understand procedure; instrumentation/scopes/monitors
should be checked preoperatively
5. Minimizing the risks and complexities of the procedure and recovery
because it is done in a “minimally invasive” fashion
Intraoperative
1. Pulmonary
a. Failure to achieve single lung ventilation.
b. Parenchymal lung injury: avoid abrupt movement of instruments
or moving instruments, which are incompletely visualized. Air
leak requires repair with ligature or stapling.
c. Contralateral tension pneumothorax.
2. Vascular
a. Segmental vessel injury (most common vascular injury): A peanut
can be used to compress the vessel followed by definitive management with electrocautery or vascular clips. Avoid prolonged electrocautery near the foramen as this may propagate and lead to neurologic injury.
b. Major vessel injury (aorta, superior vena cava, or pulmonary ves-
sels) is extremely rare (requires conversion to open thoracotomy).
3. Dural injury: If cerebrospinal fluid (CSF) leakage is noted, Gelfoam
with/without Avitene or thrombin should be gently placed into the
disc space. Persistent leakage may require CSF diversion with lumbar
drain.
4. Thoracic duct injury: This is particularly at risk in lower thoracic
spine. Attempt definitive management with clips or cautery as soon as
this is recognized.
Postoperative
1. Atelectasis (less than with open thoracotomy)
2. Retropleural effusion
3. Intercostal neuralgia: usually resolve within 6 to 12 weeks (can be minimized by use of flexible ports, trocars 쏝 12 mm in adults, and 5-mm
scopes/trocars for pediatric cases)
Suggested Readings
Crawford AH, Wall EJ, Wolf R. Video-assisted thoracoscopy. Orthop Clin
North Am 1999;30:367–385.
Regan JJ, McAfee PC. Thoracoscopy and laparoscopy of the spine. In: Bri-
dwell KH, DeWald RL, eds. The Textbook of Spinal Surgery. 2nd ed.
Philadelphia: Lippincott-Raven; 1997:2313–2331.
Regan JJ, McAfee PC, Mack MJ, eds. Atlas of Endoscopic Spine Surgery. St.
Louis: Quality Medical Publishing; 1995.
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35
The Accordion Procedure for Management of Rigid Thoracic Scoliosis
James E. Shook and Walter H. Burnham, Jr.
Goals of Surgical Treatment
The accordion procedure was developed to address problems associated
with the large rigid thoracic curve. The surgical resection of the apical-convex curve reduces curve rigidity, which allows for greater curve correction.
Diagnosis
Significant rigid lateral deviation of the thoracic spine in the frontal plane
with the apex of the curve between the T2 and T11-T12 disc.
Indications for Surgery
Large, rigid thoracic scoliosis curves (curves greater than 70 degrees that
Contraindications
Smaller and less rigid curves do not require a procedure of this magnitude.
Advantages
1. There is substantial reduction in curve rigidity and subsequent forces
required for curve correction.
2. The curve is corrected by derotation and translation rather than distraction.
3. There is maintenance of concave blood supply to the spinal cord.
4. The spinal cord is protected by preservation of the posterior one third
of the vertebral body.
5. The curve is corrected over multiple levels rather than an acute angular change.
6. Improved cosmesis.
7. Increased rates of fusion.
Disadvantages
1. Two surgical procedures are required.
2. Thoracotomy with associated morbidity.
3. Lengthened hospital course.
4. Postoperative bracing.
Procedure
1. The anterior apical portion of the spinal curve is exposed through a rib
excising thoracotomy. The rib is saved for subsequent bone grafting
(Fig. 35–1).
2. The apical four to six vertebrae that compose the most deformed portion of the spine are resected in a subtotal fashion, removing the convex cortical bone back to the rib head and anterior cortical bone utiliz-
ing a bone bur or rongeur. The anterior corpus is then decancellated to
the concave cortex maintaining the posterior one third of the vertebral
body.
3. Intervening and end discs are resected.
4. An internal thoracoplasty can then be performed if deemed necessary
to reduce a rigid chest wall deformity (Fig. 35–2).
5. An onlay bone graft from the subtotal vertebrectomies and morselized
rib is placed in the bed of the resected vertebra (Fig. 35–3).
6. Surgicel Nu-Knit absorbable hemostat (Johnson and Johnson Medical
Inc.) is placed over the morselized bone and the parietal pleura is repaired over the Surgicel. Two chest tubes are inserted (Fig. 35–4).
7. A second operation is then performed. The second procedure involves
a standard segmental posterior spinal instrumentation and fusion. Surgeon discretion determines whether the second operation is
completed under the same anesthetic or 1 week later. In most cases, we
have performed both the anterior and posterior procedures under the
same anesthetic. If the surgeon decides on the interval procedure, the
patient should remain at bed rest until the posterior instrumentation is
in place. If an internal thoracoplasty was not performed and a rigid rib
deformity persists, a posterior thoracoplasty may be added at this
point (Fig. 35–5).
Postoperative Care
Chest tubes are removed when fluid output is less than 100 cc in a 24-hour
period and the chest x-ray is clear. The patient is mobilized and an orthosis
(TLSO) is used if the patient is large (heavier than 130 lbs) or a thoracoplasty was performed (for guidance of rib remodeling).
Case Presentation
See Figures 35–6, 35–7, 35–8, and 35–9.
Exposure Secrets
A nutrient vessel enters the vertebral body at its mid-posterior center. The
depth of this vessel is the posterior one fourth to one third of the anteroposterior diameter of the vertebra. We limit our vertebral resection to the
ventral limit of this vessel. When the nutrient vessel is encountered, a
rapid flush of blood is observed and easily identified. The bleeding is
easily controlled with bone wax. In our experience, it is rare to lose more
than 250 cc of blood with the anterior subtotal vertebral resections as long
as the nutrient vessel at each level is identified and rapidly plugged with
bone wax.
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