Upload
lacity
View
0
Download
0
Embed Size (px)
Citation preview
ORIGINAL ARTICLE
Posterior-only correction of Scheuermann kyphosis using pediclescrews: economical optimization through screw density reduction
Eyal Behrbalk • Ofir Uri • Ruth M. Parks •
Michael Paul Grevitt • Marcus Rickert •
Bronek Maximilian Boszczyk
Received: 14 July 2013 / Revised: 30 May 2014 / Accepted: 14 July 2014
� Springer-Verlag Berlin Heidelberg 2014
Abstract
Introduction Posterior-only approach using pedicle
screws’ fixation has emerged as the preferred surgical
technique for Scheuermann kyphosis (SK) correction.
Insertion of multiple pedicle screws while increasing sta-
bility increases also the risk of complications related to
screw malpositioning and surgical cost. The optimal screw
density required in surgical correction of SK remains
unclear. This study compares the safety and efficacy of low
screw density (LSD) versus high screw density (HSD)
technique used in posterior-only correction of SK.
Methods Twenty-one patients underwent surgical cor-
rection of SK between 2007 and 2011 and were reviewed
after a mean of 29 months. HSD technique (i.e., 100 % of
available pedicles, averaged 25.2 ± 4 screws) was used in
10 cases and LSD technique (i.e., 54–69 % of available
pedicles in a pre-determined pattern, averaged 16.8 ± 1.3
screws; p \ 0.001) was used in 11 cases. Kyphosis cor-
rection was assessed by comparing thoracic kyphosis,
lumbar lordosis and sagittal balance on preoperative and
postoperative radiographs. Cost saving analysis was per-
formed for each group.
Results Preoperative thoracic kyphosis, lumbar lordosis
and sagittal balance were similar for both groups. The
average postoperative kyphosis correction was similar in
both HSD and LSD groups (29� ± 9� vs. 34� ± 6�,
respectively; p = 0.14). Complication occurred in four
patients (19 %) in the HSD group and in two patients (9 %)
in the LSD group (p = 0.56). Three patients required re-
operation. Compared to HSD using LSD saves 4,200£ per
patient in hardware and 88,200£ for the entire cohort.
Conclusion LSD technique is as safe and effective as
HSD technique in posterior-only correction of SK.
Implant-related cost could be reduced by 32 %.
Keywords Scheuermann kyphosis � Economical
optimization � Screw density � Pedicular screw � Cost
reduction � Correction
Introduction
Surgical correction of Scheuermann kyphosis (SK) is an
uncommon and challenging procedure. According to the
Scoliosis Research Society records less than 1 % of
spine surgeries performed by its members are carried out
for the treatment of SK [1]. The natural history of SK
seems to follow a benign course in the majority of cases,
with settling of symptoms and stabilization of the
deformity at skeletal maturity [2–4]. However, both eti-
ology and natural history of SK are not fully understood
and, therefore, the best practice strategy for the treatment
of SK remains unclear. Despite controversies, surgical
correction is usually reserved to skeletally mature
patients with severe back pain and curves over 75� [5–
7]. The first case series of SK correction was described
in 1975 by Bradford et al. [8]; deformity correction and
In this investigation the high screw density cohort is contributed by
Mr. Sm Mehdian.
E. Behrbalk (&) � R. M. Parks � M. P. Grevitt � M. Rickert �B. M. Boszczyk
The Centre for Spinal Studies and Surgery, Queen’s Medical
Centre, Nottingham, UK
e-mail: [email protected]
O. Uri
Royal National Orthopaedic Hospital NHS Trust Brockley Hill,
Stanmore, Middlesex, UK
123
Eur Spine J
DOI 10.1007/s00586-014-3472-y
fusion were performed through a posterior-only approach
with Harrington instrumentation. Unfortunately, due to
unacceptably high complications rate and correction loss
with this technique, a combined approach of anterior
release followed by posterior instrumented spinal fusion
has been considered as the gold standard for SK cor-
rection for many years [3, 9]. The introduction of the
pedicle screw (which enables strong three column fixa-
tion) into spine surgery over the past years resulted in
growing evidence that posterior-only correction is com-
parable to combined anterior–posterior approach for the
treatment of SK [10–14]. Posterior-only approach short-
ens surgical time, minimizes exposure and blood loss
and may reduce postoperative complications [11, 15] and
has emerged as the preferred approach by many sur-
geons [2, 3, 16]. Using multiple pedicle screws increases
fixation stability, but may also increase the risk of
complications associated with screw malpositioning. The
optimal pedicle screw density (i.e., number of pedicle
screw used/number of available pedicle insertion sites)
required to maintain a stable fixation following correc-
tion of spinal deformities remains controversial. Previous
studies which evaluated the correlation of fixation
anchors’ density with curve correction and fixation sta-
bility in scoliosis surgery, showed no conclusive findings
[17, 18]. Nevertheless, the higher failure rate associated
with kyphosis correction compared to other spinal
deformities [1] may deter surgeons from using less than
the maximal fixation screws available.
To our knowledge, no previous study has evaluated
the influence of pedicle screw fixation density on defor-
mity correction and fixation stability in the treatment of
SK. The purpose of the current study was to evaluate the
safety and efficacy of low pedicle screws density (LSD)
technique in correcting SK through a posterior-only
approach and to compare the results to those of correc-
tion using high screw density technique (HSD) along
with determining the potential for implant-related cost
savings.
Patients and methods
Study design
The study was conducted at our spine surgery unit in our
university affiliated teaching hospital. We retrospectively
reviewed and analyzed data of patients who underwent
surgical correction for severe SK between January 2007
and January 2011. This investigation fulfills the criteria of
service evaluation of our institution and as such does not
require formal ethics committee appraisal.
Patient population
Medical records and imaging of 21 patients (average age
21 ± 7 years, 86 % males) who underwent surgical cor-
rection of advanced symptomatic SK in our hospital were
reviewed after a minimum follow-up of 24 months. Clin-
ical data were obtained prospectively and included detailed
medical history, physical examination and imaging of the
entire spine (i.e., high quality anterior–posterior and lateral
radiographs and MRI scan). All the patients had persistent
symptoms of severe back pain affecting activities of daily
living, not improving with non-operative treatment of at
least 12 months. No patient had neurological deficit. Pre-
operative imaging demonstrated thoracic kyphosis C60� in
all the patients (average 75� ± 9�, range 61�–96�). Ante-
rior wedging C5� at C3 consecutive thoracic vertebras,
endplate irregularities and/or Schmorl nodules were also
found in all the patients. No concomitant spinal pathology
(e.g., congenital anomaly, previous surgery, coronal plane
deformity C10�) was found in preoperative MRI scans of
the study cohort. All procedures were performed through a
posterior-only approach using pedicle screws. In ten
patients, pedicle screws were inserted into all available
pedicles in the fused segment (‘‘high screw density’’
technique), i.e., 100 % of available pedicles were used. In
11 patients pedicle screw density was reduced by avoiding
placement in all pedicles across the apex of deformity
(‘‘low screw density’’ technique), i.e., 65 ± 5 % of pedi-
cles were used (range, 54–69 %). The average number of
pedicle screws used per patient in the HSD group was
25.2 ± 4 compared to 16.8 ± 1.3 screws per patient which
were used in the LSD group (p \ 0.01). The average
number of levels fused per patient was similar for both
HSD and LSD groups (12.6 ± 2 vs. 13 ± 0.4, respec-
tively; p = 0.52). Naturally, the screws’ density in the
HSD group was significantly higher than in the LSD group
(100 ± 0 % vs. 65 ± 5 %, respectively, p \ 0.01).
Surgical technique
All corrections were performed by one of three senior spine
consultants team in our spine unit, using a similar surgical
technique. A posterior-only approach using pedicle screws
fixation was performed in all the cases. The superior and
inferior ends of the curve were determined preoperatively
by the Cobb method. Patients were placed prone on the
operating table with appropriate padding and support. A
standard posterior midline approach was used. The para-
spinal muscles were sub-periosteally elevated and the
posterior elements of the fusion segments were exposure.
Mono axial pedicle screws’ system was used in all the
procedures. Deformity correction and fusion were carried
Eur Spine J
123
out from the first thoracic vertebra involved in the kyphosis
to the lumbar vertebra below the first lordotic disc [19].
Pedicle screws were inserted using a free-hand technique
or under controlled insertion with the help of image
intensifier. Screw insertion point was at the junction of the
transverse process and lateral margin of the superior facet
joint in the lower thoracic and lumbar spine and at the
junction of the superior margin of the transverse processes
with the middle of the inferior facet joint in the upper
thoracic spine. To enable deformity correction, an apical
Ponte osteotomy and posterior column shortening were
carried out [20, 21]. Deformity correction was performed
utilizing two 6-mm titanium rod with or without cross-
links. Somatosensory and neurogenic motor-evoked
potentials were monitored throughout the procedure. The
posterior elements were decorticated to bleeding bone and
the bone graft obtained was placed along the length of the
instrumentation to facilitate fusion.
Screw placement patterns
HSD technique was used by one consultant and his team
in 10 patients and included screws’ insertion into all
available pedicles in the fused segment (i.e., 100 % of
pedicles were used). The fused levels in these patients
were T2-L2 in seven patients, T1-L2 in one patient, T2-
L3 in one patient and T7-L1 in one patient. LSD
technique was used by two consultants and their team in
11 patients and included: (1) screws’ insertion into all
four pedicles at the two most cephalad and two most
caudal levels of the fused segment, (2) screws at the
remaining levels were inserted either into alternate pedi-
cles of each level (pattern A, used in 6 patient), or into
both pedicles of every other level (pattern B, used in 5
patients). The fused levels in the LSD group were T3-L3
in eight patients, T1-L2 in one patient, T3-L2 in one
patient and T1-L1 in one patient. Figures 1, 2, and 3 show
the screw insertion patterns used in this study.
Postoperatively, Patients were encouraged to sit and
stand within the first 24 h after surgery under supervision
of a physiotherapist and were advanced to assisted ambu-
lation as tolerated on the second postoperative day. Return
to unrestricted activity was allowed at 3–6 months pro-
vided that radiographs confirmed fusion.
Outcome measures
Kyphosis correction was assessed by comparing preoper-
ative unassisted standing lateral radiographs of the entire
spine with postoperative radiographs at the latest follow-up
of at least 24 months. Radiographic parameters of kyphosis
correction were measured digitally by two spine fellows
and one orthopedic specialist not involved in the opera-
tions, using PACS (picture archiving and communication
Fig. 1 25-year-old male with advanced symptomatic Scheuermann
kyphosis, unresponsive to non-operative treatment. A surgical
correction through a posterior-only approach using 100 % pedicle
screw density technique was performed. Preoperative (a) and post-
operative standing lateral radiographs at 30-month follow-up (b) are
presented
Eur Spine J
123
system, General Electric, Health care systems, Easton
Turnpike Fairfield, US) and included: (1) thoracic kypho-
sis, defined as T5-T12 Cobb angle, (2) lumbar lordosis,
defined as L1-S1 Cobb angle, (3) sagittal balance, defined
as the displacement (measured in mm) of C7 plumb line in
relation to the superior posterior endplate of S1 (i.e.,
considered positive if anterior and negative if posterior).
Sagittal balance correction was defined as the overall shift
of C7 plumb line in relation to the posterior–superior
endplate of S1 (i.e., if the sagittal balance was changed
from ?20 mm before surgery to -10 mm after surgery, the
‘‘correction’’ was considered as 30 mm).
Fig. 2 A 19-year-old male with advanced symptomatic Scheuermann
kyphosis, unresponsive to non-operative treatment. A surgical
correction through a posterior-only approach using low pedicle screw
density technique (pattern A) was performed. Preoperative (a) and
postoperative standing lateral radiographs at 24-month follow-up
(b) are presented
Fig. 3 A 20-year-old male with advanced symptomatic Scheuermann
kyphosis, unresponsive to non-operative treatment. A surgical
correction through a posterior-only approach using low pedicle screw
density technique (pattern B) was performed. Preoperative (a) and
postoperative standing lateral radiographs at 24-month follow-up
(b) are presented
Eur Spine J
123
Data Analysis
Continuous parameters are described as the mean and the
standard deviation (SD) and categorical parameters are
described as proportions. Comparison between the groups
is presented with 95 % confidence intervals (CI) around the
difference. Unpaired two-tailed t test was used to compare
preoperative and postoperative values of continuous
parameters between the groups. Categorical parameters
were compared using two-tailed Fisher’s exact test. Sta-
tistical analysis was performed using SPSS for Windows
software (version 16.0; IBM, Chicago, Illinois). A proba-
bility of \0.05 was considered statistically significant.
Results
Both HSD and LSD groups were similar in terms of
patients’ age, gender, preoperative radiographic parameters
(e.g., thoracic kyphosis, lumbar lordosis and sagittal bal-
ance) and postoperative follow-up. The average thoracic
kyphosis was similar in early postoperative radiographs
and at the latest follow-up for both the HSD group
(42� ± 7� and 43� ± 9�, respectively; p = 0.78) and the
LSD group (44� ± 9� and 44� ± 8�, respectively;
p = 0.99). At the latest follow-up, thoracic kyphosis cor-
rection was 29� ± 9� in the HSD group and 34� ± 6� in
the LSD group (p = 0.14). Lumbar-lordosis correction was
15� ± 11� in the HSD group and 23� ± 14� in the LSD
group (p = 0.16). Sagittal balance correction was similar
for both HSD and LSD as well (16 ± 12 mm and
23 ± 15 mm, respectively; p = 0.25). Comparison of
patients’ characteristics and clinical data between the HSD
and LSD groups is summarized in Table 1.
We further analyzed LSD group based on the two dif-
ferent patterns of pedicle screws’ insertion, pattern A and B
as described earlier. Preoperative patients’ characteristics
and radiographic parameters of deformity were similar for
both groups. Postoperative outcomes of kyphosis correc-
tion were similar for both groups as well (Table 2).
Complications occurred in 6 of 21 patients in our cohort
(28 %). Four complications occurred in the HSD group
Table 1 Comparison of
patients’ characteristics and
clinical data between the high
screw density and the low screw
density groups
Values are presented as
mean ± SD and (range)a Defined as the ratio between
the number of screws used and
the number of available pediclesb Anterior displacement of C7
plumb line in relation to the
posterior–superior sacral corner
was considered positive and
posterior displacement as
negativec Comparison was performed
using unpaired two-tailed t testd Comparison was performed
using two-tailed Fisher’s exact
test
High screw
density
N = 10
Low screw density
N = 11
Difference
(95 % CI)
p value
Age at surgery, years 22 ± 8 (15–34) 19 ± 6 (12–33) 3 (-3, 9) 0.34c
Gender, N (%)
Males 8 (80 %) 10 (90.9 %) 10.9 % (-21, 42) 0.58d
Females 2 (20 %) 1 (9.1 %)
Number of levels fused 12.6 ± 2.0 (7–14) 13.0 ± 0.4
(12–14)
0.4 (-1, 2) 0.52c
Number of screws inserted 25.2 ± 4.0
(14–28)
16.8 ± 1.3
(14–18)
8.4 (6, 11) \0.01c
Screw densitya, % 100 ± 0
(100–100)
65 ± 5 (54–69) 35 (32, 38) \0.01c
Postoperative follow-up,
months
32 ± 11 (24–56) 26 ± 6 (24–42) 6 (-2, 14) 0.13c
Thoracic kyphosis, degrees
Preoperative 72 ± 7 78 ± 9 6 (-1, 13) 0.10c
Early postoperative 42 ± 7 44 ± 9 2 (-5, 9) 0.58c
Latest follow-up 43 ± 9 44 ± 8 1 (-7, 9) 0.79c
Correction 29 ± 9 34 ± 6 5 (-2, 12) 0.14c
Lumbar lordosis, degrees
Preoperative 71 ± 8 73 ± 12 2 (-7, 11) 0.66c
Latest follow-up 56 ± 10 50 ± 14 6 (-5, 17) 0.27c
Correction 15 ± 11 23 ± 14 8 (-4, 19) 0.16c
Sagittal balanceb, mm
Preoperative 27 ± 28 20 ± 24 7 (-17, 31) 0.54c
Latest follow-up 11 ± 21 -3 ± 25 14 (-7, 35) 0.18c
Correction 16 ± 12 23 ± 15 7 (-5, 19) 0.25c
Eur Spine J
123
(19 %) and two (9 %) in the LSD group (p = 0.56).
Complications in the HSD group included: (1) one patient
had screw penetration into T9 disc space that was detected
on postoperative spine radiograph. The patient remained
asymptomatic and no further intervention was required, (2)
another patient developed pseudo-arthrosis at T7-8 level
with breakage of both fixation rods at 6-month follow-up
and correction loss of 15�, subsequently. Nevertheless, the
patient had only marginal symptoms and declined further
surgery, (3) a third patient developed unilateral three-level
screw loosening (T3–T5 levels) at 3-month follow-up,
without correction loss. The patient underwent revision
surgery with instrumented fusion after infection free
interval of 5 months and normalization of all inflammatory
markers. At latest follow-up no recurrence of infection
noted, radiographs showed good bone fusion mass, (4) the
forth patient had unilateral screw loosening at L1–L2 levels
detected on 12-month radiographs after complete bone
union occurred. The patient remained asymptomatic and no
further intervention was required. Complications in the
LSD group included: (1) one patient developed proximal
junctional kyphosis of 20� at T2–T3 level at 1.5 months
follow-up. The patient was re-operated and T3 Smith-
Petersen osteotomy with fusion extension to T1 level was
carried out. Following this procedure, the patient
developed spastic paraplegia, which resolved over a
6-month time, (2) another patient developed acute deep
wound infection which was treated by surgical debride-
ment 2 weeks postoperatively and intravenous antibiotics.
Further debridement with metalwork removal was carried
out 4 weeks later on due to persistent infection. The patient
underwent second stage revision with instrumentation after
clearance of the infection (5 months after the index pro-
cedure) without recurrence of infection at the latest follow-
up.
Discussion
The first case series reporting on outcomes of surgical
treatment for SK was published in 1975 by Bradford et al.
[8] who reviewed 22 patients following posterior-only
correction and fusion with Harrington instrumentation.
Thoracic kyphosis was corrected from an average of 72�before surgery to 47� at 35-month follow-up. Correction
loss of 21� in average was noticed in 16 patients (72 %).
Larger and more rigid sagittal curves were found to
increase the risk for correction loss and implant failure.
Combined anterior–posterior fusion was recommended for
these deformities and remained the treatment of choice for
Table 2 Subgroup analysis of
the low screw density group
based on screw insertion pattern
Values are presented as
mean ± SDa Pedicle screws were inserted
into all four pedicles at the two
most cephalad and two most
caudal levels of the fused
segment and into either the
opposite pedicle of each of the
remaining levels (Pattern A), or
into both pedicles of every other
level of the remaining levels
(Pattern B)b Defined as the ratio between
the number of screws used and
the number of available pediclesc Anterior displacement of C7
plumb line in relation to the
posterior–superior sacral corner
was considered positive and
posterior displacement as
negatived Comparison was performed
using unpaired two-tailed t teste Comparison was performed
using two-tailed Fisher’s exact
test
Low screw
density pattern Aa
N = 6
Low screw
density pattern Ba
N = 5
Difference
(95 % CI)
p value
Age at surgery, years 17 ± 3 21 ± 7 4 (-3, 11) 0.23d
Gender, N (%)
Males 6 (100 %) 4 (80 %) 20 % (-22, 62) 0.45e
Females 0 (0 %) 1 (20 %)
Number of levels fused 12.8 ± 0.4 13.2 ± 0.5 0.4 (-0.2, 1) 0.17d
Number of screws inserted 16.6 ± 1.5 17.0 ± 1.2 0.4 (-1.4, 2.3) 0.64d
Screw densityb, % 65 ± 6 64 ± 4 1 (-6, 8) 0.75d
Postoperative follow-up, months 26 ± 3 28 ± 7 2 (-5, 9) 0.54d
Thoracic kyphosis, degrees
Preoperative 79 ± 10 78 ± 9 1 (-12, 11) 0.86d
Early postoperative 42 ± 11 45 ± 8 3 (-10, 16) 0.62d
Latest follow-up 43 ± 9 45 ± 7 2 (-9, 13) 0.69d
Correction 36 ± 7 33 ± 5 3 (-5, 11) 0.44d
Lumbar lordosis, degrees
Preoperative 74. ± 15 72 ± 9 2 (-15, 19) 0.80d
Latest follow-up 52 ± 17 47 ± 10 5 (-14, 24) 0.57d
Correction 22 ± 17 25 ± 13 3 (-18, 24) 0.75d
Sagittal balancec, mm
Preoperative 26 ± 29 14 ± 15 12 (-20, 44) 0.42d
Latest follow-up -2 ± 35 -3 ± 7 1 (-35, 37) 0.95d
Correction 28 ± 16 17 ± 13 11 (-9, 31) 0.24d
Eur Spine J
123
many years [3, 5, 9]. With the advancement in spine sur-
gery and the introduction of pedicle screw, which enables
solid three column fixation, the posterior-only approach
(using pedicle screws) has emerged as the preferred sur-
gical technique for the treatment of SK [2, 3, 16, 18].
Multiple pedicle screws are usually required when
posterior-only approach is used in correction of spinal
deformities. While improving construct stability, HSD also
increases the risk of complications related to screw mal-
positioning, increased time of surgery and raises the sur-
gical cost. The optimal pedicle screw density required to
maintain stability in surgical correction of spinal defor-
mities remains a topic of debate. In theory, for flexible
deformities, one might consider a construct build on strong
foundation screw only (e.g., six screws in three cranial
vertebras and six screws in three caudal ones); this low SD
construct (*25 % SD) might achieve the same clinical and
radiological results as our constructs. Clements et al. [22]
found direct correlation between HSD and major curve
correction in 292 patients following scoliosis correction.
Quan et al. [23] on the other hand found no correlation
between pedicle screws’ density and the magnitude of
coronal and sagittal curves correction in 49 patients fol-
lowing scoliosis correction. SK has been associated with
higher risk of postoperative complications including cor-
rection loss [1, 3, 5] suggesting that HSD may be required
to protect and maintain correction when operating on
patients with this complex deformity. Supporting that, is
Lee et al. [11] case series of 39 patients reported on 18
patients who underwent surgical correction of SK through a
posterior-only approach with 100 % pedicle screws density
technique. Kyphosis was corrected from 84� before surgery
to 40� at a mean of 32 months after surgery. Correction loss
in these patients was 2.2� and no complication occurred.
Kyphosis was corrected from 84� before surgery to 40� at a
mean of 32 months after surgery. Correction loss in these
patients was 2.2� and no complication occurred. A recent
study by Koller et al. [24] followed 111 patients for 2 years
after SK deformity correction, performing anterior release
and posterior segmental fusion using pedicle screws. Their
study reported on 87.3 ± 12.9 % screw density construct
(closer to our HSD group), but with only 8 vertebrae
involved in fusion (our study involved 12.6 ± 2 vertebrae
fusion), the preoperative TK as well as amount of defor-
mity correction at last follow-up was similar in their study
and ours (67.2 ± 12.2� with 30.1 ± 13.5� correction,
75 ± 9� with 31.6� correction, respectively). Interestingly,
although their construct was significantly shorter than ours
they found no correction loss over time and no correlation
between the level of the last instrumented vertebrae and
rate of distal junctional kyphosis.
Whether a 100 % pedicle screws density and long
constructs are indeed necessary in SK correction remains
unclear. Financial constraints, therefore, demand evalua-
tion of the necessity of maximal implant usage. To our
knowledge, no previous study has evaluated the outcome of
LSD technique in the treatment of SK.
The purpose of our study was to evaluate the safety and
efficacy of LSD technique in correcting SK through a
posterior-only approach. The findings of our study show
that posterior-only correction of SK using less pedicle
screw (i.e., 54–69 % of available pedicles) was as safe and
effective as correction using 100 % of available pedicles.
All sagittal correction parameters measured (e.g., thoracic
kyphosis, lumber lordosis and sagittal balance) were sim-
ilar for the HSD group (with an average of 25.2 screws
used per patient) and the LSD group (with an average of
16.8 screws used per patient) at a mean postoperative
follow-up of 32 months and 26 months, respectively. The
pattern of pedicle screws’ insertion in our LSD group did
not seem to affect the correction outcomes. Taking into
account these similar clinical results and the high cost of
each pedicle screw (around £300 per screw), the LSD
technique seems to be more cost effective.
Six of our patients (28 %) presented postoperative
complications (four implant-related complications, one
junctional kyphosis and one deep infection) and three of
them (14 %) required re-operation. Bradford et al. [8] in the
first report of SK correction through a posterior-only
approach described postoperative complications in 18 of
their 22 patients including correction loss, implant failure
and infection. Coe et al. [1] in a multicenter analysis of 683
procedures for SK correction reported on postoperative
complication rate of 15 % in patients who were operated on
through a posterior-only approach. Dennis et al. [25]
reported on postoperative development of proximal junc-
tional kyphosis (of 20� in average) in 20 of their 67 patients
(30 %) who underwent posterior-only correction of SK. Lee
et al. [11], on the other hand, had no postoperative com-
plications in their cohort of 18 patients following posterior-
only correction of SK. The relative high complication rate
found in our study and others [1, 2, 8, 25] highlights that
despite great advances in spine surgery over the past dec-
ades, surgical correction of SK remains a complex and
challenging procedure which should be performed only by
experienced surgeons after careful consideration.
Hardware cost–benefit analysis: UK price of one mono
axial pedicular screw and its cap is 350–600£ (average
500£). Two rods cost 400–600£ (average 520£). Hardware
cost of the typical HSD construct calculated with the
average hardware price amounts to 13,120£ (25.2 screws);
in the LSD construct this amounts to 8,920£ (16.8 screws).
Assuming even pricing across all implants used, this
amounts to 4,200£ (32 %) saving in hardware alone per
case in the LSD group and a total of 88,200£ for all 21
patients of the study cohort.
Eur Spine J
123
Our study has several potential limitations. First, the
cohort numbers are relatively small. However, given that
surgical correction of SK is a complex and uncommon
procedure we believe that these limitations are inevitable.
Second, the average sagittal curve correction in our study
was *30� (29� and 34� in the HSD and LSD groups,
respectively). Whether our results remain unchanged with
greater overall correction (e.g., kyphosis correction of
*40� as reported by Lee et al. [11] ) has to be further
evaluated. Third, this study focused on the radiological
outcome of SK correction regardless of clinical outcomes.
Assuming that radiological outcome of a surgical proce-
dure is an accurate reflection of the clinical results may be
misleading.
In conclusion, our findings suggest that LSD technique
using 54–69 % of available pedicles is as safe and effective
as HSD technique using 100 % of available pedicles for
posterior-only correction of SK, while incurring significant
cost savings.
Conflict of interest None.
References
1. Coe JD, Smith JS, Berven S, Arlet V, Donaldson W, Hanson D,
Mudiyam R, Perra J, Owen J, Marks MC, Shaffrey CI (2010)
Complications of spinal fusion for scheuermann kyphosis: a
report of the scoliosis research society morbidity and mortality
committee. Spine 35:99–103. doi:10.1097/BRS.0b013e3181
c47f0f
2. Tsirikos A, Jain A (2011) Scheuermann’s kyphosis; current
controversies. J Bone Joint Surg Br 93:857–864
3. Wood KB, Melikian R, Villamil F (2012) Adult Scheuermann
kyphosis: evaluation, management, and new developments. J Am
Acad Orthop Surg 20:113–121. doi:10.5435/JAAOS-20-02-113
4. Poolman R, Been H, Ubags L (2002) Clinical outcome and
radiographic results after operative treatment of Scheuermann’s
disease. Eur Spine J 11:561–569
5. Lowe TG, Kasten MD (1994) An analysis of sagittal curves and
balance after Cotrel-Dubousset instrumentation for kyphosis
secondary to Scheuermann’s disease: a review of 32 patients.
Spine 19:1680–1685
6. Lenke L (2004) Kyphosis of the thoracic and thoracolumbar spine
in the pediatric patient: prevention and treatment of surgical
complications. Instr Course Lect 53:501
7. Lamartina C (2010) Posterior surgery in Scheuermann’s kypho-
sis. Eur Spine J 19:515–516
8. Bradford DS, Moe JH, Montalvo F, Winter R (1975) Scheuer-
mann’s kyphosis. Results of surgical treatment by posterior spine
arthrodesis in twenty-two patients. J Bone and Joint Surg
57:439–448
9. Bradford DS, Ahmed KB, Moe J, Winter R, Lonstein J (1980)
The surgical management of patients with Scheuermann’s
disease. J Bone Joint Surg 62:705–712
10. Sturm PF, Dobson JC, Armstrong GW (1993) The surgical
management of Scheuermann’s disease. Spine 18:685–691
11. Lee SS, Lenke LG, Kuklo TR, Valente L, Bridwell KH, Sides B,
Blanke KM (2006) Comparison of Scheuermann kyphosis cor-
rection by posterior-only thoracic pedicle screw fixation versus
combined anterior/posterior fusion. Spine 31:2316–2321. doi:10.
1097/01.brs.0000238977.36165.b8
12. Geck MJ, Macagno A, Ponte A, Shufflebarger HL (2007) The
Ponte procedure: posterior only treatment of Scheuermann’s
kyphosis using segmental posterior shortening and pedicle screw
instrumentation. J Spinal Disord Tech 20:586–593
13. Koptan WM, ElMiligui YH, ElSebaie HB (2009) All pedicle
screw instrumentation for Scheuermann’s kyphosis correction: is
it worth it? Spine J 9:296–302
14. Johnston CE, Elerson E, Dagher G (2005) Correction of adoles-
cent hyperkyphosis with posterior-only threaded rod compression
instrumentation: is anterior spinal fusion still necessary? Spine
30:1528–1534
15. Graham EJ, Lenke LG, Lowe TG, Betz RR, Bridwell KH, Kong
Y, Blanke K (2000) Prospective pulmonary function evaluation
following open thoracotomy for anterior spinal fusion in ado-
lescent idiopathic scoliosis. Spine 25:2319–2325
16. Lowe TG, Line BG (2007) Evidence based medicine: analysis of
Scheuermann kyphosis. Spine 32:S115–S119. doi:10.1097/BRS.
0b013e3181354501
17. Chen J, Yang C, Ran B, Wang Y, Wang C, Zhu X, Bai Y, Li M
(2013) Correction of Lenke 5 adolescent idiopathic scoliosis
using pedicle screw instrumentation: does implant density influ-
ence the correction? Spine
18. Clements DH, Betz RR, Newton PO, Rohmiller M, Marks MC,
Bastrom T (2009) Correlation of scoliosis curve correction with
the number and type of fixation anchors. Spine 34:2147–2150.
doi:10.1097/BRS.0b013e3181adb35d
19. Arlet V, Schlenzka D (2005) Scheuermann’s kyphosis: surgical
management. Eur Spine J 14:817–827
20. Grevitt M, Kamath V, Avadhani A, Rajasekaran S (2010) Cor-
rection of thoracic kyphosis with Ponte osteotomy. Eur Spine J
19:351–352
21. La Maida GA, Misaggi B (2012) Posterior only treatment of adult
thoracic kyphosis with multiple Ponte osteotomies and pedicle
screw instrumentation. Eur Spine J 21:1–5
22. Clements DH, Betz RR, Newton PO, Rohmiller M, Marks MC,
Bastrom T (2009) Correlation of scoliosis curve correction with
the number and type of fixation anchors. Spine 34:2147–2150
23. Quan GM, Gibson MJ (2010) Correction of main thoracic ado-
lescent idiopathic scoliosis using pedicle screw instrumentation:
does higher implant density improve correction? Spine
35:562–567. doi:10.1097/BRS.0b013e3181b4af34
24. Koller H, Juliane Z, Umstaetter M, Meier O, Schmidt R, Hitzl W
(2014) Surgical treatment of Scheuermann’s kyphosis using a
combined antero-posterior strategy and pedicle screw constructs:
efficacy, radiographic and clinical outcomes in 111 cases. Eur
Spine J 23:180–191
25. Denis F, Sun EC, Winter RB (2009) Incidence and risk factors for
proximal and distal junctional kyphosis following surgical treat-
ment for Scheuermann kyphosis: minimum five-year follow-up.
Spine 34:E729–E734
Eur Spine J
123