Surgical Treatment of Lumbar Kyphoscoliosis
Surgical Treatment of Degenerative Lumbar Kyphoscoliosis
Kao-Wha Chang, MD, Tsung-Chein Chen, MD, Ku-I Chang, MD
Taiwan Spine Center and Department of Orthopaedic Surgery
Armed Forces Taichung General Hospital, Taiwan, Republic of China
Address all correspondence and reprint requests to: Kao-Wha Chang, MD
Taiwan Spine Center and Department of Orthopaedic Surgery,
Armed Forces Taichung General Hospital, Taiwan.
No.348, Sec.2, Chung-Shan Rd
Taiping City, Taichung Hsein, Taiwan, Republic of China.
TEL:(8864)23935823; FAX: (8864)23920136
E-Mail: kao-wha@803.org.tw
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Surgical Treatment of Lumbar Kyphoscoliosis
Abstract
Study Design. Retrospective study.
Objective. To review radiographic and clinical results of patients with degenerative
lumbar kyphoscoliosis (DLKS) treated with neurologic decompression, asymmetric
closing-opening wedge osteotomy (COWO), instrumentation-assisted correction
according to a preoperatively made template, and circumferential fusion with a
posterior-only approach.
Summary of Background Data. DLKS causes sagittal and coronal imbalance,
posterior sacral migration away from the center of gravity line, muscle weakness,
osteoporosis, spinal stenosis and instability, rigid deformities, and implant and
adjacent-segment failure after instrumentation-assisted corrective surgery. We know
of no reports of the results and complications of current instrumentation and
osteotomy techniques to treat DLKS.
Methods. Thirty-one patients with DLKS (mean age, 72.3 years; range, 65–78 years)
treated for intractable pain were followed up for a mean of 4.1 years. We assessed
their preoperative, 2-month postoperative, and final follow-up radiographs and
administered a questionnaire to measure changes in pain, function, self-image, patient
satisfaction with surgery, and postoperative complications.
Results. Final radiographs showed increased L1–S1 lordosis from 11.3° to -50.5°
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Surgical Treatment of Lumbar Kyphoscoliosis
(increase of 61.8°), correction of kyphotic deformity from 64.3° to -14.1°, and
correction of scoliotic deformity from 48.9° to 8.3°. Sagittal imbalance significantly
improved from 68.8 to 27.1 mm, whereas the sacrofemoral distance decreased from
59.3 to -5.1 mm, and the sacral inclination angle increased from 9.7° to 34.3°.
Subjective pain was significantly and persistently reduced. Most patients maintained
good correction and had good clinical results. No major complication occurred. Eight
patients (26%) developed junctional kyphosis.
Conclusions. Thorough neurologic decompression, the best possible correction and
restoration of sound associations among the spine, the pelvis, and the center of gravity,
are crucial in the surgical treatment of DLKS to obtain satisfactory clinical results.
The 3-column release procedure, COWO, and procedures of neurologic
decompression and circumferential fusion make DLKS flexible enough to be
manipulated adequately from behind. A posterior-only approach minimizes the risk of
surgery. Junctional kyphosis remains a significant problem.
Key Words: center of gravity; closing-opening wedge osteotomy; degenerative
lumbar kyphoscoliosis; junctional kyphosis; promontory; template.
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Surgical Treatment of Lumbar Kyphoscoliosis
Key Points

Thorough neurologic decompression, the best possible correction, and restoration
of coronal and sagittal spinal balance and of proper lumbopelvic congruity to
bring the promontory close to the center of gravity line are crucial in the surgical
treatment of DLKS to obtain a satisfactory clinical results.

A lumbosacral curve to bring the promontory close to the center of gravity line
can be simulated and a template can be made accordingly.

Asymmetric closing-opening wedge osteotomy, procedures of neurologic
decompression and circumferential fusion make DLKS flexible enough to be
adequately manipulated from behind to conform the lumbosacral curve to the
contour of the template.

Posterior-only approach and staged operation minimize the risk of surgery.

Junctional kyphosis remains a significant problem in DLKS patients treated with
instrumentation-assited correction.
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Surgical Treatment of Lumbar Kyphoscoliosis
Mini Abstract
Thorough neurologic decompression, the best possible correction and restoration of a
sound associations among the spine, pelvis and the center of gravity are crucial in
surgical treatment of degenerative lumbar kyphoscoliosis to obtain satisfactory
clinical results.
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Surgical Treatment of Lumbar Kyphoscoliosis
Introduction
Degenerative lumbar kyphoscoliosis (DLKS), or lumbar degenerative changes,
including narrowing of several discs and vertebral wedging or collapse with
predominant kyphosis and scoliosis. The curve involves segments from the lower
thorax to L5 with an apex at L2 or L3. It may result from degeneration of de novo or
preexisting idiopathic kyphoscoliosis,1-3 as well as iatrogenic or traumatic causes.
Lumbar muscles can be fatigued due to overwork against a center of gravity far
in front of the lumbosacral junction, an important cause of pain in DLKS.4 Correction
of the deformity need to restore coronal and sagittal spinal balance and to reconstruct
lumbopelvic congruity to bring the promontory near the center of gravity.
We reviewed the results of DLKS treated with neurologic decompression,
asymmetric closing-opening wedge osteotomy (COWO), instrumentation-assisted
correction according to a preoperatively made template, and circumferential fusion
with a posterior-only approach and determined factors influencing satisfactory
outcomes.
Materials and Methods
Patients
We reviewed 37 patients with DLKS undergoing surgery in 2000–2004. Two
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Surgical Treatment of Lumbar Kyphoscoliosis
died, and 4 dropped out; therefore, 8 men and 23 women (mean age at surgery, 72.3
years; range, 65–78 years) were followed up for a mean of 4.1 years (range, 2–6.3
years). DLKS related to causes other than degeneration, such as iatrogenic or revision
surgery was not included in this study. Their clinical records were reviewed for
demographic data, surgical times, intraoperative blood loss, and complications.
Evaluations
Preoperative, 2-month postoperative, and final follow-up radiographs were
analyzed.
Sagittal measurements were made on a 36-in. standing lateral views of the entire
spine and upper femur obtained with the hips and knees fully extended. Measurements
included curvatures and Cobb angles (negative for lordosis), T1–T12 kyphosis, L1–S1
lordosis (negative values), inclination of the upper surface of the sacrum5 (SIA,
positive for anterior inclination), and sacrofemoral distance (SFD, distance between
plumb lines through the hip axis6,7 and sacral promontory; positive values for femora
anterior to the promontory). SFD was a function of the inclination of the upper sacral
surface.4,8 Sagittal offset was the horizontal distance between the C7 sagittal plumb
line and the posterior superior corner of S1. Because the posterosuperior aspect of the
S1 body was the reference, the normal neutral range for sagittal balance was 0–4 ㎝
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Surgical Treatment of Lumbar Kyphoscoliosis
from this point (plumb line through the L5–S1 disc).
Coronal measurements included curvatures and Cobb angles. Coronal balance
was assessed on posteroanterior radiographs as deviation of the C7 plumb line from
the median sacral line. Magnetic resonance imaging was used to confirm spinal
stenosis and identify neural compression (retropulsed bone or disc). All patients
received the standard method of measuring bone density via dura-energy radiograph
absorptiometry (DEXA) scan. Ten patients were osteopenic ( T-scores between -1.0
and -2.5 ) and twenty-one patients were osteoporotic (T-scores less than -2.5).
At last follow-up, patients completed a modified 46-item questionnaire9
regarding demographics, function (8 questions; maximal = 5, minimal = 1), pain (3
questions; 0 = none, 9 = severe), self-image (scored similar to function), and
satisfaction.
Data were compared with the Mann-Whitney U test with significance set at 0.05.
Surgery
Patients were positioned prone with padding at the iliac crests, knees, shoulders,
and chest. The abdomen was free to reduce intraoperative bleeding. The osteotomy
site (usually L2) was over the hinge in the table so that, as the osteotomy was closed,
the table could be moved from the neutral to V position. A standard posterior midline
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Surgical Treatment of Lumbar Kyphoscoliosis
incision was made (usually from proximal level identified as the stable, neural and
horizontal vertebra with a stable suprajacent disc in the coronal and sagittal planes to
the sacrum). The spine was bilaterally exposed to the tip of the transverse processes
with a strictly subperiosteal approach to reduce bleeding. Pedicle screws were inserted
(usually from T9 to the sacrum except at the osteotomy level).
Wide posterior decompression and formal lateral-recess decompression and
foraminotomy of the involved stenotic levels were usually necessary to treat
neurogenic claudication and pain.
The vertebral pedicles for osteotomy were decorticated with a rongeur to
facilitate guide-pin insertion. They were entered with a small-diameter curette guided
with intraoperative fluoroscopy and radiography. The ideal path was from the lateral
side of the medial pedicular wall to the anteromedial wall of the vertebral body
midway between the endplates. The lamina and vertebral pedicles were removed. A
blunt-end cage trial was hammered to penetrate the anterior cortex of the vertebral
body transvertebrally and bilaterally. The path in the middle column was enlarged by
pushing the cancellous bone up and down. The posterior cortex of the vertebral body
was carefully removed by using a curette or rongeur on both sides. The posterior and
middle columns were completely released.
We simulated a lumbosacral curve that brought the promontory close to the
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Surgical Treatment of Lumbar Kyphoscoliosis
center of gravity line and made a template.
The lumbopelvic portion of the standing lateral radiograph was magnified to life
size and printed on transparent paper, which was divided into the hips, lumbopelvic
portion caudal to the COWO, and thoracolumbar portion cephalic to the COWO. We
located the hip axis and rotated and translated the paper with the lumbopelvic portion
to a position with the original pelvic-radius length and pelvic radius–S1 angle
(constants for each individual)6,7 and with an SFD of 0 mm. (The center of gravity is
normally directly under the promontory.10)
We translated the paper with the thoracolumbar portion to continue with the
lumbopelvic portion and rotated the former with a hinge at the pedicular base of the
osteomized vertebrae to simulate the closing and opening wedges for COWO. The
posterior superior corner of L1 (point L1) was on the extension of a curve connecting
the posterior superior corner of S1 (point S), the posterior edge of each lumbopelvic
vertebral body, and the pedicular base of the osteomized vertebrae. The curve between
S and L1 was the temporary template. One end of a rod of appropriate length was bent
to conform to the template. Points S and L1 were marked on the rod, which was
locked at 2 points with 2 pedicle screws.
Legaye et al11 postulated a predictive equation for lumbar lordosis based on
pelvic parameters. According to the manipulated figure, pelvic parameters included
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Surgical Treatment of Lumbar Kyphoscoliosis
pelvic incidence, overhang of S1, sacral slope, and pelvic tilting were measured to
predict the lumbar lordosis to be created.11 Approximately two-thirds of L1–S1
lordoses are below L4.12 For L1–L5 lordosis, 40% are at L4–5 in subjects ≥70 years.13
Total L1–S1 lordosis was estimated accordingly.
The contour of the rod segment responding to L4–S1 was used to approximate
the lordosis between the pedicle screws to the estimated L1–S1 lordosis. In theory, the
promontory can be brought near the center of gravity line if the lumbosacral curve can
be reconstructed accordingly.
Deformity Correction
The rod was connected to the pedicle screws on the convex side marked S and
L1. The operating table was slowly moved to a V position to facilitate correction and
to provide space for lumbopelvic sagittal translation and rotation around the hip axis.
The surgeon rotated the convex rod to correct scoliosis, and then pushed the rod at the
osteotomy site, and compressed the pedicle screws immediately above and below the
osteotomy to correct kyphotic deformity and create the lumbosacral lordosis.
Fracturing of the anterior cortex and anterior longitudinal ligament was sometimes
heard. We thus created an asymmetrical closing wedge of the posterior and middle
columns at the convex and posterolateral sides of the osteomized vertebrae and an
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Surgical Treatment of Lumbar Kyphoscoliosis
opening wedge of the anterior column at the concave and anteromedial side of the
osteomized vertebrae.
Procedures of neurologic decompression and circumferential fusion could
provide adequate release at L4-S1 segment to conform the segment to the contour of
the rod responding to the L4-S1 segment.
The lateral mass was closed down tightly. The correction was fixed with another
concave rod and fused with autogenous bone grafts. The roots and dura were checked
to ensure that no residual compression by centrally enlarging the canal. A Woodson
elevator was passed up and down the canal through the area of central decompression
to detect dorsal neural compression created by osteotomy closure. We performed
wake-up tests.
Bilateral iliac screws were used to protect the sacral screws and sacrum from
failure and fracture. Circumferential fusion with posteriorly placed wedge-shaped
cages or strut grafts, bone, and bone substitutes were used for anterior-column support
and fusion at L5–S1. For patients with T-scores less than -2.5, we augmented the most
cephalad adjacent vertebrae with 2 intrabody cages (with the thickest size that the
vertebrae can fit) in the anterior and middle columns to prevent the segment failure.
We stopped the operation when blood loss was >5000 mL and resumed it 1–2
weeks after the patient recovered. Patients ambulated 48 hours later and used
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Surgical Treatment of Lumbar Kyphoscoliosis
custom-made thoracolumbar orthoses for 6 months.
Results
Mean estimated blood loss was 3650 mL (range, 2519–9362 mL). Mean
operating time was 245 minutes (range, 191–313 minutes).
No perioperative deaths or neurovascular complications occurred. Two patients
had postoperative pneumonia, 1 had a superficial infection. All were successfully
treated.
One patient had a pulmonary embolus complicated by congestive heart failure,
which resolved after medical management. One patient had wound dehiscence 3
weeks after initial surgery. All cultures were negative, and after the wound was
surgically repaired, the patient did well. Ten patients developed paralytic ileus, which
resolved after a Levin tube was inserted and their oral intake restricted.
No sacral screw pullout occurred. One patient was found to have the most
cephalad screw pullout and required extension to the upper thoracic spine. Two rods
in 2 patients broke at L5–S1 due to pseudoarthrosis, and 2 dural tears occurred during
surgery; all were managed uneventfully.
Eight of 31 patients (26%) develop progressive junctional kyphosis at the
cephalad end of the construct. One developed late compression fracture of the most
cephalad vertebral body included in the construct. A patient without preventive cage
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Surgical Treatment of Lumbar Kyphoscoliosis
augmentation developed a compression fracture immediately above the instrumented
level. Two patients had failure 2 segment cephalad from the last instrumented
vertebrae. All leading to kyphosis and required extension to the upper thoracic spine.
Four did not have radiographic evidence of any compression fracture but still seemed
to become progressive kyphotic and two required extension to the upper thoracic
spine. Surgery was staged in 5 patients (Table 1).
Radiographic Results
Six patients had normal preoperative sagittal C7 plumb-line distance but
substantially increased SFDs compared with norms.4,6 The preoperative estimated and
postoperative mean L1-S1 lordoses was -43.3o±9.8 o (range -36 - -61 o) and
-52.3 o±12 o (range -35 - -63 o) respectively , a significant difference (P = 0.04). No
patient had notable loss of correction between 2-month and final follow-up except in
thoracic kyphosis and sagittal balance (Table 2). Figures 1 and 2 show representative
radiographs.
Questionnaire
Mean pain scores were 7.9 ± 1.1 before and 2.3 ± 1.5 after surgery (P = 0.01).
Four (13%) reported equal postoperative pain. In 27 (87%), surgery directly decreased
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Surgical Treatment of Lumbar Kyphoscoliosis
their pain.
Median preoperative and postoperative function scores were 9 and 15,
respectively (P = 0.03). Function improved in 16 (52%) patients, was unchanged in 13
(42%), and decreased in 2 (6%).
Median self-image scores improved from 4.5 before to 9.5 after surgery (P =
0.03), improving in 28 (90%) patients, not changing in 3 (10%), and worsening in
none.
Twenty-nine (94%) patients were extremely or somewhat satisfied with the
results; 2 (6%), somewhat dissatisfied; and none, extremely dissatisfied.
Twenty-seven (87%) felt much better or better after surgery, and none felt much worse.
Twenty-nine (94%) would choose treatment again.
Discussion
DLKS is increasingly prevalent and predominantly affects the elderly, who may be
frail because of qualitative and quantitative weakening of the bones or osteoporosis,
which makes instrumentation and fusion difficult. DLKS can exacerbate disc
degeneration, spinal stenosis, and facet arthropathy, increasing spinal rigidity and
making treatment difficult. Risks of instrumentation failure, nonunion, and
adjacent-segment failure are considerable.
Severe deformities can increase surgical morbidity and mortality.14–18 Therefore,
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Surgical Treatment of Lumbar Kyphoscoliosis
conservative measures must be attempted first.2,19,20 Goals of surgery are to resolve
intractable low back pain or radicular pain that interferes with activities of daily living
or to make it controllable with medications, to reduce the drug load, and to fuse the
spine in an anatomic position as normal as possible. Cosmesis and progression of
deformity are not indications for surgery.
In DLKS, increased extremity radicular pain and claudication are due to neural
compression; this is relieved with thorough neurologic decompression. Degenerative
pain is caused by disc and facet instability and degeneration due to deformity and
imbalance; this is relieved with deformity correction, fixation, and fusion. Myogenic
pain is caused by lumbar muscular fatigue and is relieved by restoring sagittal and
coronal balance and approximating the promontory to the center of gravity line.4
Spinal stenosis aggravates underlying spinal stenosis attributable to DLKS.
Asymmetric collapse, rotation, frequent rotatory and lateral listhesis, and
spondylolisthesis or retrolisthesis all compromise the neural elements. Neural
impingement can occur centrally and in the lateral recess and foramina. Facet-joint
hypertrophy and pedicular kinking caused by disc-height collapse are commonly
present. Thorough neurologic decompensation is crucial to treat neurogenic
claudication and pain.
DLKS can produce sagittal imbalance. Patients cannot stand erect without
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Surgical Treatment of Lumbar Kyphoscoliosis
compensatory hip extension, knee flexion, and overwork of the erector spinal
musculature because a reduced moment arm compromises the mechanical advantage.
The result is muscle fatigue and activity-related pain. As patients age, muscular
weakness, adjacent disc degeneration, and hip and pelvic disease may decrease
compensation and increase disability. During reconstructive surgery, restoration of
normal sagittal balance is more critical than correction of coronal deformity.21
Global sagittal spinal alignment was historically quantified by measuring a
vertical line from the center of the C7 vertebral body with respect to the posterior
superior corner of S1.22–24 This sagittal vertical axis describes the cumulative balance
of the sagittal spinal curves of the trunk but not the entire body, which occurs at the
center of gravity. C7 plumb and gravity lines are not in the same places in the sagittal
plane.9 The center of gravity is near the axis through the hip for pelvic rotation and
normally directly wonder the promotory10. Improved association of the spine, pelvis,
and center of gravity or economical sagittal balance reduces the work of the spinae
erecta and hamstring muscles to achieve balance during normal activity.
According to normal standards,4,5,25 all patients in this study had decreased
inclination in the upper sacral surface, or backward rotation, which can be explained
by compensated lumbar kyphosis. The line connecting both hip joints was in front of
the promontory, increasing the SFD. Even in natural standing, the lumbar extensors
17
Surgical Treatment of Lumbar Kyphoscoliosis
overworked to achieve balance. Muscular fatigue, spasm, and pain are clinical
symptoms of attempted correction of truncal and whole-body imbalance. Most
patients with DLKS have increased C7 plumb-line distances and SFDs. Correction of
lumbar kyphosis and scoliosis and restoration of the C7 sagittal plumb line without
approximately relocating the center of gravity under the promontory does not relieve
myogenic pain in DLKS. Six patients with a C7 plumb line through the L5–S1 disc
had significantly increased SFDs (with intractable myogenic pain). All described
decreased pain after the SFD was substantially decreased.
Deformity correction for DLKS should include reconstructing lumbopelvic
congruity to bring the promontory near the center of gravity line for myogenic pain
relief. Instrumentation-augmented correction must extend to the pelvis.
Pelvic-radius lengths and pelvic radius–S1 angles are constants for patients with
continual low back pain7 and likely patients with DLKS. Adult pelvic anatomy is
stable, and the pelvic-radius–S1 angle is considered to be constant or to have a fixed
geometric shape in the sacropelvis and should not change with pelvic rotation or
sagittal translation. In adult volunteers and in patients with spinal disorders, pelvic
morphology and lumbosacral lordosis are strongly correlated and complementary in
determining lumbopelvic lordosis,7 which is strongly correlated with pelvic balance
around the hip axis. SFD determines pelvic balance. Therefore, given the 2 anatomic
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Surgical Treatment of Lumbar Kyphoscoliosis
constants and 0-mm SFD and given the motion behavior of the vertebral column
above and below the osteotomy during correction, a lumbosacral curve to bring the
promontory close to the center of gravity line could be simulated approximately. By
making fine adjustment of the curvature to match the estimated lumbosacral lordosis
according to the Legaye equation11 and to reported distributions,12,13 we approximated
lumbopelvic balance to the physiologic state. We reconstructed a lumbosacral curve
with 50.5° L1–S1 lordosis and decreased SFD from 59.3 to -5.1 mm. However, there
was significant difference in L1-S1 lordosis between preoperative estimation (43.3o)
and measurement of postoperative radiographs (52.3). We believed it was due to
flexibility and deformability of the rod. Although the method were approximate, the
results demonstrated it was efficient.
The position of the gravity line depends on pelvic orientation.8 When the pelvis
rotates anteriorly, the distance from the line to the sacrum decreases. Because the
caudal end of the construct is sacral and ilial and because corrected lumbar kyphosis
and restored lumbosacral lordosis are accomplished by rotating and pushing the
prebent rod at the COWO site, the lumbopelvic segment caudal to that site rotated
anteriorly and around the hip axis. Therefore, the sacral–gravity line distance
decreased. Procedures of neurologic decompression and circumferential fusion could
provide adequate release at L4-S1 segment to conform the segment to the contour of
19
Surgical Treatment of Lumbar Kyphoscoliosis
the rod responding to the L4-S1 segment and could further decrease the sacral-gravity
line distance. All patients obtained significantly decreased sagittal plumb-line
distances and SFDs and increased inclination of the upper sacral surface. Restoration
of lasting spinal and whole-body balance was possible.
Surgery may have improved deformity and relieved pain more than it improved
function. The questions about function might have been most appropriate for
able-bodied patients or those with 1- or 2-segment disease, whereas objective
measures (e.g., walking on a treadmill, gait, ambulatory oxygen consumption) might
have been most valid for our group, in whom heavy work or competitive athletics was
unexpected.
Because of the rigidity of the deformities, anterior release may be needed to
restore flexibility before posterior instrumentation-augmented correction can be
successful.14,26–28 However, thoracotomy and laparotomy are associated with
considerable morbidity. Combined with a posterior approach for complete correction,
they hinder rapid recovery. Transthoracic approaches can cause pulmonary
complications (atelectasis, pneumonia, pleural effusion, and pneumothorax),29,30
chylothorax,31 and pain syndrome.32 Retroperitoneal approaches can injure the viscera,
great vessels (increasing blood loss and blood transfusions), and superior hypogastric
nerve plexus (leading to impotence and bladder dysfunction).30,33 Other complications
20
Surgical Treatment of Lumbar Kyphoscoliosis
are deep vein thrombosis due to venous retraction, abdominal incisional hernia, and
prolonged postoperative ileus.30 Deformity correction is a goal if it is not inordinately
risky. We performed anterior and posterior release and instrumentation-assisted
correction and fusion with a posterior-only approach. Because our patients underwent
1 procedure, rehabilitation was hastened, and risks of delayed mobilization were
avoided.
The spine should be fused in a balanced position as normal as possible because
insufficient deformity correction involving posterior instrumentation alone may lead
to lost correction, pseudoarthrosis, increased reoperation rates, or poor clinical
results.1,15 Our satisfactory results highlight the utility of asymmetric COWO to
surgically treat DLKS. It is a 3-column release and can make the rigid deformity
flexible enough to be adequately manipulated form behind to obtain optimal
correction.
Anatomic limitations of 1 vertebral body restrict closing wedge osteotomy to
about 35°.34–37 In this study as well as our another study38, higher correction was
achieved with COWO by fracturing the anterior vertebral cortex.
COWO shortens the posterior and middle spinal columns. Gertzbein and Harris35
limited corrections to approximately 30–40°. With kyphotic correction >40°, the
spinal cord may be too long for the shortened posterior-middle column and become
21
Surgical Treatment of Lumbar Kyphoscoliosis
curved, kinked, or damaged. For posterior transvertebral osteotomy, Lehmer et al36
recommend that correction at any level should not exceed approximately 35°. For
transpedicular wedge resection osteotomy, Berven et al37 recommend that correction
of a sagittal deformity should be below L1 and of a magnitude correctable with a
closing wedge <45°. We demonstrated that a closing wedge at L2 is safe.38,39
Redundant cauda equina may cause no problems if enough bone is removed to
accommodate the excess neural tissue.
Paralytic ileus increased with COWO and might have been associated with
elongation of lumbar anterior column, which caused tension on the anterior abdominal
organs. However, all cases resolved with gastric-tube decompression.
Fractures of the cephalad instrumented vertebra, or fractures of adjacent or
remote unfused vertebra, have been recognized as an early and late complication in
the adult deformity population. Osteoporosis and positive sagittal balance appear to be
risk factors. These fractures can compromise construct integrity, with loss of proximal
segment control, increased risk of pseudoarthrosis, and loss of correction in sagittal
and coronal planes.40,41 The risk particularly increases in patients older than 60 years;
in women (including postmenopausal women); and in those with osteoporosis,
preoperative instability, long fusion segments, floating fusions, or lost coronal or
sagittal balance.41
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Surgical Treatment of Lumbar Kyphoscoliosis
A concentrated flexion moment in the most cephalic adjacent vertebra after rigid
pedicle screw fixation seems to cause compression fractures.42,43 We reviewed our
experience (unreported data) with 33 patients who were older than 65 years and
osteoporotic with T-scores less then -2.5 and underwent thoracolumbosacral fusion.
25% of them developed compression fracture one vertebral body cephalad from the
last instrumented vertebrae and resulted in junctional kyphosis after an average of 5
yrs follow-up. No valid means prevent this failure. Use of a new implant or interbody
cage with decreased stiffness or the injection of augmentation materials (e.g.,
carbonated apatite) into the most cephalic adjacent vertebra might soon be
encouraged.44 Our patients were older than 65 years and had osteoporosis and long
fusion segments; no adjacent-segment failure occurred after restoration of balance,
preventive intrabody-cage augmentation, and the avoidance of floating fusion.
However, two patients were found to have fracture 1 segment above the
cage-augmentation, one patient without preventive cage argumentation had adjacent
segment fracture and one patient had fracture of the most cephalad vertebral body
included in the construct. All developed progressive junctional kyphosis and required
extension to the upper thoracic spine.
Multisegmental progression of the global thoracic kyphosis and junctional
kyphosis resulted in significant loss of sagittal balance. Eight patients (26%)
23
Surgical Treatment of Lumbar Kyphoscoliosis
developed junctional kyphosis. The four patients with an associated fracture and two
of the four patient without an associated fracture required reoperation for progressive
junctional kyphosis. Deward and Stanley45 believe progressive junctional kyphosis is
an inevitable consequence of multilevel instrumentation in patients with poor bone
stock. A potential approach to this problem is to perform limited fusion with the
intention of staging proximal extension as the junctional kyphosis progresses.
Increased motion and stress concentration at this junctional area can induce
instrumentation failure and adjacent segment problems and lead to junctional
kyphosis. We believe there may be several other reasons why we failed to decrease
the incidence of junctional kyphosis despite aggressive preventive efforts to prevent
junctional kyphosis at the cephalad end of the construct. As a group of patients
presented with lumbar kyphosis and many had substantial positive sagittal balance.
Give the long-standing nature of their deformity, these patients may have equilibrated
to a more forward-flexed position and, therefore continued to stand in this familiar,
stooped posture, despite the local change in lumbosacral lordosis achieved during the
instrumented reconstruction. This would suggest a role for some, as yet, unidentified
neurologic or proprioceptive mechanism contributes to an individual’s ability to
maintain a neural sagittal balance.Undoubtedly, the severe reconditioning of the
lumbar paraspinal musculature that occur as the result of the posterior exposure
24
Surgical Treatment of Lumbar Kyphoscoliosis
influences the patients’ ability to stand erect.
Techniques to reduce instrumentation pullout in osteoporotic spines include the
use of multiple points of segmental fixation, sublaminar wires, undertapping or no
tapping of the screw hole before pedicle screws are used, combined pedicle screws
with laminar hooks at the same level, cement augmentation of pedicle screws, and
decreased deformity correction, as well as not ending the instrumentation in a
kyphotic segment.45,46
Kyphosis correction involves cantilever bending forces. Forces on the superior
and inferior ends of the instrumentation resist anterior spinal displacement. Therefore,
failure manifests as rod fracture at the apex of the deformity or, most likely, failure of
the segmental fixation at either end of the construct. The most effective way to
prevent implant pullout during DLKS correction is accomplished the correction after
thorough 3-column release to minimize the posteriorly directed force. Reconstructing
anatomic alignment and changing the curvature from kyphosis to lordosis markedly
reduces the posterior force and decreases the incidence of postoperative screw
pullout.38,47
The lumbosacral junction has a high mechanical demand and wide pedicles at L5
and S1. Therefore, high rates of pseudoarthrosis with lumbosacral fusion and implant
failure occur with long fusions to the sacrum.48–51 Solitary sacral fixation points with
25
Surgical Treatment of Lumbar Kyphoscoliosis
S1 pedicle screws are often insufficient. Augmentation to protect these screws include
the use of divergent sacral alar screws,48 S2 pedicle screws,49 and S1 foraminal
hooks.50 The Luque-Galveston technique for lumbosacral fixation is technically
demanding, especially bending of the rods into appropriate alignment.51 Jackson et
al52 reported lumbosacral fixation by using the iliac buttress. Iliac support improves
biomechanical strength and seems to provide acceptable results.50–57
One advantage of iliac screws is that they can be combined with sacral screws to
improve rigid fixation of the sacropelvis. Two instrumentation failures occurred at
L5–S1 but no pullout or breakage of S1 screws. For long fusions to the sacrum, a
montage of bilateral S1 and iliac screws effectively protected the sacral screws.
Nonetheless, pseudarthrosis occurred at L5–S1, which unexpectedly manifested as rod
breakage on both sides. Anterior-column support and anterior bone grafting reduced
but did not eliminate the complication. We suggest using high concentrations of
autogenous bone and potential supplementation with bone morphogenetic protein,
anteriorly and posteriorly.
In conclusion , successful treatment of DLKS requires thorough neurologic
decompression and restoration of coronal and sagittal spinal balance and proper
lumbopelvic congruity to bring the promontory near the center of gravity line. With
careful attention to the details, to good medical treatment, and to the surgical
26
Surgical Treatment of Lumbar Kyphoscoliosis
technique, gratifying result can usually be obtained.
27
Surgical Treatment of Lumbar Kyphoscoliosis
References
1.
Grubb SA, Lipscomb HJ. Diagnostic findings in painful adult scoliosis. Spine
1992;17:518–27.
2.
Ogilvie JW. Adult scoliosis: evaluation and no surgical treatment. Instr Course
Lect 1992;41:251–5.
3.
Simmons ED. Surgical treatment of patients with lumbar spinal stenosis with
associated scoliosis. Clin Orthop 2001;384:45–53.
4.
Takemitsu Y, Harada Y, Iwahara T, et al. Lumbar degenerative kyphosis. Clinical,
radiological and epidemiological studies. Spine 1988;13:1317–26.
5.
Kobayashi T, Atsuta Y, Matsuno T, et al. A longitudinal study of congruent
sagittal spinal alignment in an adult cohort. Spine 2004;29:671–6.
6.
Jackson PR. Spinal balance, lumbopelvic alignments around the "hip axis" and
positioning for surgery. Spine State Art Rev 1977;11:33–58.
7.
Jackson RP, Kanemura T, Kawakami N. Lumbopelvic lordosis and pelvic
balance on repeated standing lateral radiographs of adult volunteers and
untreated patients with constant low back pain. Spine 2000:25:575–86.
8.
Roussouly P, Gollogly S, Noseda O, et al. The vertical Projection of the sum of
the ground reactive forces of a standing patient is not the same as C7 plumb line.
Spine 2006,31:E320–5.
9.
Booth KC, Bridwell KH, Lenke LG. Complications and predictive factions for
the successful treatment of flatback deformity (fixed sagittal imbalance)
Spine1999;24:1712–20.
10. White AA III, Panjabi MM. Clinical biomechanics of the spine. Philadelphia: JB
Lippincott, 1990:642–8.
11. Legaye J, Duval-Beaupere G, Hecquct J et al. Pelvic incidence: A fundamental
28
Surgical Treatment of Lumbar Kyphoscoliosis
pelvic parameter three-dimensional regulation of spinal sagittal curves. Eur
Spine 1998:7;99–103.
12. Jackson RP, McManus AC. Radiographic analysis of sagittal plane alignment and
balance in standing volunteers and patients with low back pain matched for age,
sex, and size: A prospective controlled clinical study. Spine 1994;19:1611–8.
13. Hammerberg EM, Wood KB. Sagittal profile of the elderly. J Spinal Disord Tech
2003;16:44–50.
14. Bradford DS. Adult scoliosis. Current concepts of treatment. Clin Orthop
1988;229:70–87.
15. Bradford DS, Tay BK, Hu SS. Adult scoliosis: surgical indications, operative
management, complications, and outcomes. Spine 1999;24:2617–29.
16. Swank S, Lonstein JE, Moe JH, et al. Surgical treatment of adult scoliosis. A
review of 222 cases. J Bone Joint Surg Am 1981;63:268–87.
17. Takahashi S, Delecrin J, Passuti N. Surgical treatment of idiopathic scoliosis in
adults: an age-related analysis of outcome. Spine 2002;27:1742–8.
18. Van Dam BE. Operative treatment of adult scoliosis with posterior fusion and
instrumentation. Orthop Clin North Am 1988;19:353–9.
19. Nachemson A. Adult scoliosis and back pain. Spine 1979;4:513–7.
20. Robin GC Span Y, Steinberg R, et al. Scoliosis in the elderly: a follow-up study.
Spine 1982;7:355–9.
21. Glassman SD, Berven S, Bridwell K, et al. Correlation of radiographic
parameters and clinical symptoms in adult scoliosis. Spine 2005;30:682–8.
22. Gelb DE, Lenke LG, Bridwell KH, et al. An analysis of sagittal spinal alignment
in 100 asymptomatic middle and older aged volunteers. Spine 1995;20:1351–8.
23. Van Royen BJ, Toussaint HM, Kingma I, et al. Accuracy of the sagittal vertical
29
Surgical Treatment of Lumbar Kyphoscoliosis
axis in a standing lateral radiograph as a measurement of balance in spinal
deformities. Eur Spine J 1998;7:408–12.
24. Vedantam R, Lenke LG, Bridwell KH, et al. The effect of variation in arm
position on sagittal spinal alignment. Spine 2000;25:2204–9.
25. Jackson RP, Hales C. Congruent spinopelvic alignment on standing lateral
radiographs of adult volunteers. Spine 2000;25:2808–15.
26. Byrd JA III, Scoles PV, Winter RB, et al. Adult idiopathic scoliosis treated by
anterior and posterior spinal fusion. J Bone Joint Surg Am 1987;69:843–50.
27. Johnson JR, Holt RT. Combined use of anterior and posterior surgery for adult
scoliosis. Orthop Clin North Am 1988;19:361–70.
28. Winter RB, Lonstein JE. Adult idiopathic scoliosis treated with Luque or
Harrington rods and sublaminar wiring. J Bone Joint Surg Am 1989;71:1308–13.
29. Westfall SH, Akbarnia BA, Merenda JT, et al. Exposure of the anterior spine.
Technique, complications, and results in 85 patients. Am J Surg 1987;154:700–4.
30. Zileli M, Naderi S, Benzel EC, et al. Preoperative and surgical planning for
avoiding complications. In: Benzel EC, ed. Spine Surgery: Techniques,
Complication Avoidance, and Management. New York: Churchill Livingstone,
1999:135–42.
31. Bolesta MJ, Bohlman HH. Late sequelae of thoracolumbar fractures and
fracture-dislocations: surgical treatment. In: Frymoyer JW, ed. The Adult Spine:
Principles and Practice. Vol 2. New York: Raven, 1991:1331–52.
32. Skubic JW, Kostuik JP: Thoracic pain syndromes and thoracic disc herniation, in
Frymoyer JW, ed. The Adult spine: Principles and Practice. Vol 2. New York:
Raven, 1991:1443–61.
33. Found EM, Weinstein JN: Surgical approaches to the lumbar spine. In: Frymoyer
30
Surgical Treatment of Lumbar Kyphoscoliosis
JW, ed. The Adult Spine: Principles and Practice. Vol 2. New York: Raven,
1991:1523–34.
34. Leatherman KD, Dickson RA. Two-staged corrective surgery for congenital
deformities of the spine. J Bone Joint Surg Br 1979;61:324–8.
35. Gertzbein SD, Harris MB. Wedge osteotomy for the correction of posttraumatic
kyphosis. Spine 1992;17:374–9.
36. Lehmer SM, Keppler L, Buscup RS, et al. Posterior transvertebral osteotomy for
adult thoracolumbar kyphosis. Spine 1994;19:2060–7.
37. Berven SH, Deviren V, Smith JA, et al. Management of fixed sagittal plane
deformities. Spine 2001;26:2036–43.
38. Chang KW, Chen YY, Lin CC, et al. Closing wedge osteotomy versus opening
wedge osteotomy in ankylosing spondylitis with thoracolumbar kyphotic
deformity. Spine 2005;30:1584–93.
39. Chang KW, Chen YY, Lin CC, et al. Apical lordosating osteotomy and minimal
segment fixation for the treatment of thoracic or thoracolumbar osteoporotic
kyphosis. Spine 2005;30:1674–81.
40. Aota Y, Kumano K, Hirabayashi S. Postfusion instability at the adjacent
segments after rigid pedicle screw fixation for degenerative lumbar spinal
disorders. J Spinal Disord 1995;8:464–73.
41. Etebar S, Cahill DW. Risk factors for adjacent-segment failure following lumbar
fixation with rigid instrumentation for degenerative instability. J Neurosurg
1999;90:163–9.
31
Surgical Treatment of Lumbar Kyphoscoliosis
42. Krag MH. Biomechanics of thoracolumbar spinal fixation: A review. Spine
1991;16(Suppl):S84–99.
43. Lowe TG, Kasten, MD. An analysis of sagittal curves and balance after
Cotrel-Dubousset instrumentation for kyphosis secondary to Scheuermann’s
disease: A review of 32 patients. Spine 1994;19:1680–5.
44. Lotz JC, Hu CC, Chiu DFM, et al. Carbonated apatite cement augmentation of
pedicle screw fixation in the lumbar spine. Spine 1997;22:2716–23.
45. Dewald CJ, Stanley T. Instrumentation-related complications of multilevel fusion
for adult spinal deformity patients over age 65. Spine 2006;31:S144-51.
46. Hu SS. Internal fixation in the osteoporotic spine. Spine 1997;22:43S–8.
47. Saita K, Hoshino Y, Kikkawa I, et al. Posterior spinal shortening for paraplegia
after vertebral collapse caused by osteoporosis. Spine 2000;25:2832–5.
48. Leong JC, Lu WW, Zheng Y, et al. Comparison of the strengths of lumbosacral
fixation achieved with techniques using one and two triangulated sacral screws.
Spine 1998;23:2289–94.
49. Alegre GM, Gupta MC, Bay BK, et al. S1 screw bending moment with posterior
spinal instrumentation across the lumbosacral junction after unilateral iliac crest
harvest. Spine 2001;26:1950–5.
50. Stovall DO Jr, Goodrich JA, Lundy D, et al. Sacral fixation technique in
lumbosacral fusion. Spine 1997;22:32–7.
51. Allen BL Jr, Ferguson RL. The Galveston technique of pelvic fixation with L-rod
instrumentation of the spine. Spine 1984;9:388–94.
52. Jackson RP, McManus AC. The iliac buttress. A computed tomographic study of
sacral anatomy. Spine 1993;18:1318–28.
53. Cunningham BW, Lewis SJ, Long J, et al. Biomechanical evaluation of
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Surgical Treatment of Lumbar Kyphoscoliosis
lumbosacral reconstruction techniques for spondylolisthesis: An in vitro porcine
model. Spine 2002;27:2321–7.
54. Lebwohl NH, Cunningham BW, Dmitriev A, et al. Biomechanical comparison of
lumbosacral fixation techniques in a calf spine model. Spine 2002;27:2312–20.
55. McCord DH, Cunningham BW, Shono Y, et al. Biomechanical analysis of
lumbosacral fixation. Spine 1992;17:S235–43.
56. Farcy JP, Rawlins BA, Glassman SD. Technique and results of fixation to the
sacrum with iliosacral screws. Spine 1992;17:S190–5.
57. Kuklo TR, Bridwell KH, Lewis SJ, et al. Minimum 2-year analysis of
sacropelvic fixation and L5-S1 fusion using S1 and iliac screws. Spine
2001;26:1976–83.
33
Surgical Treatment of Lumbar Kyphoscoliosis
Table 1
Complications
Perioperative death
0
Neurologic deficit
0
Wound dehiscence
1
Congestive heart failure
1
Pneumonia
2
Paralytic ileus
10
Superficial infection
1
Cephalad end screw pullout
1
Caudal end screw pullout
0
Upper instrumented vertebrae fracture
1
Adjacent – segment fracture
1
Remote – segment fracture
2
Cephalad junctional kyphosis
8
Implant failure / nonunion
2
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Surgical Treatment of Lumbar Kyphoscoliosis
Table 2
Radiographic Data Summary
Measurement
Preoperative
Postoperative
2 months
Last Follow-Up
Correction
Loss of correction
T1–T12 kyphosis (°)
25 ± 9.1 (-7- 48)
28.3 ± 7.8 (12 - 55)
37.8 ± 8.9 (13–53)
12.8 ± 3.1 (4.1–13.7) †
9.5 ± 2.5 (1.1–5.1) †
L1–S1 lordosis (°)
11.3 ± 3.2 (-5.7–21.3)
-52.3 ± 12 (-33 to -63)
-50.5 ± 11 (-34 to -65.3)*
61.8 ± 11.4 (49.3–80.4)†
1.8 ± 3.3 (0.7–3.8)
Kyphosis (°)
64.3 ± 12.4 (49.1–73.1)
-13.3 ± 4.7 (-5 to -22)
-14.1 ± 4.5 (-5.3 to -24.4)
78.4 ± 21.5 (58.4–91.4)†
0.8 ± 2.1 (0.1–4.7)
Scoliosis (°)
48.9 ± 14.8 (32.3–71.6)
7.7 ± 4.1 (0 - 17)
8.3 ± 4.5 (0-14.8)
40.6 ± 13.6 (31.6–52.1) †
0.6 ± 2.8 (0–2.3)
Sagittal balance (mm)
68.8 ± 11.3 (9.1–91.3)
-3.8 ± 4.0 (-11-22)
27.1 ± 3.2 (-5.1-45.2)
41.7 ± 15.8 (11.3–71.3)†
30.9 ± 8.3 (11.1–38.3) †
Coronal balance (mm) 41.2 ± 11.3 (0–57.1)
14.5 ± 3.1 (0-18)
13.3 ± 2.1 (0–17.1)
27.9 ± 7.1 (10.1–36.1)†
1.2 ± 1.3 (0–2.3)
SIA (°)
9.7 ± 4.8 (-9.8–18.1)
36.1 ± 7.1 (22-41)
34.3 ± 6.8 (21.1–38.8)
24.6 ± 4.7 (20.1–35.3)†
1.8 ± 0.8 (0.3–3.1)
SFD (mm)
59.3 ± 11 (29.4–78.3)
-6.1 ± 2.5 (-20-18)
-5.1 ± 2.1 (-19.1–18.3)
64.4 ± 11.3 (55.1– 83.1)†
1 ± 1.3 (0–3.3)
Data are the mean ± standard deviation (range).
*The preoperative estimate was -43.3o ± 9.8 (-36 to - 61.1o).
†
P < 0.05.
SIA = sacral inclination angle, or the angle between upper surface of the sacrum and the horizontal line.
SFD = sacrofemoral distance, or the distance between plumb line through the hip axis and sacral promontory.
35
Surgical Treatment of Lumbar Kyphoscoliosis
Figure Legends
Figure 1. 70-year-old woman. A, Presurgical images show 71° kyphosis, 65° scoliosis, 36-mm
C7 sagittal offset, 6° L1–S1 lordosis, -7° sacral inclination angle, and 58-mm SFD. B, Final
values were -14°, 7°, 10 mm, -38°, 23°, and 5 mm, respectively. She was pain free and
extremely satisfied.
Figure 2. 68-year-old woman. A, Presurgical images show 62°kyphosis, 37° scoliosis, 23-mm
C7 sagittal offset, 5° L1–S1 lordosis, -9° sacral inclination angle, and 36-mm SFD. B, Final
values were -7°, 5°, 2 mm, -50°, 28°, and -10 mm, respectively. She rarely had back pain and
was extremely satisfied.
36
Surgical Treatment of Lumbar Kyphoscoliosis
Chen SP, ♀, 70, DLKS
Kyphosis 71o
Sagittal balance 36 mm
L1-S1 6o
SFD 58mm
SIA -7o
Chen SP, ♀, 70, DLKS
Scoliosis 65o
Coronal balance 23 mm
Chen SP, ♀, 70, DLKS
Scoliosis 7o
Coronal balance 5 mm
Chen SP, ♀, 70, DLKS
Kyphosis -14o
Sagittal balance 10 mm
L1-S1 -38o
SFD 5mm
SIA 23o
HA
HA
(A)
(B)
Fig 1
37
Surgical Treatment of Lumbar Kyphoscoliosis
Chang HH, ♀, 68, DLKS
Kyphosis -7o
Sagittal balance 2 mm
L1-S1 -50o
SFD -10mm
SIA 28o
Chang HH, ♀, 68, DLKS
Kyphosis 62o
Sagittal balance 23 mm
L1-S1 5o
SFD 36mm
SIA -9o
Chang HH, ♀, 68, DLKS
Scoliosis 37o
Coronal balance 15 mm
Chang HH, ♀, 68, DLKS
Scoliosis 5o
Coronal balance 8 mm
HA
HA
(A)
(B)
Fig 2
38