Intraoperative Traction in Scoliosis: A Safe and
An Effective Tool to Achieve Better Correction
Kedar Prashant Padhye*, Jennifer Hurry, Ron EL-Hawary and Benjamin Orlik
Division of Orthopaedic Surgery, IWK Health Centre, Canada
Submission:September 12, 2022; Published: September 21, 2022
*Corresponding author: Kedar Prashant Padhye, Division of Orthopaedic Surgery, IWK Health Centre, Halifax, Nova, Scotia, Canada
How to cite this article: Kedar P P, Jennifer H, Ron EL-H, Benjamin O. Intraoperative Traction in Scoliosis: A Safe and An Effective Tool to Achieve Better Correction. Ortho & Rheum Open Access J. 2022; 20(3): 556040. DOI: 10.19080/OROAJ.2022.20.556040
Purpose: We believe that intraoperative skull-femoral traction (IOT) may effectively assist with spinal deformity correction. The aim of this study is to find out the effect of IOT in single-stage posterior arthrodesis for AIS and NM.
Methods: A retrospective cohort study was performed after Institutional Review Board (IRB) approval. Inclusion criteria were Cobb’s angle >50degrees, single stage posterior spinal instrumented fusion, follow-up >6 months. Growth-friendly surgeries were excluded. Group I consisted of patients with IOT while group II was without IOT.
Results: Group I consisted of 35 patients with mean follow-up of 2.5 years (range 9 months to 6.3 years) and group II had 58 patients with a mean follow-up of 2.11 years (range 6 months to 6.6 years). Correction index was 11.1% more (p-value <0.05) in group I compared to group II. Mean blood loss and operative time were 662 ml (range 205 to 1513ml) and 7.14 hours (range 4.6 to 9.2 hours) in group I, while 647 ml (range 170 to 2200 ml) and 6.04 hours (range 4.1 to 10.2 hours) in group II. OR time was significantly more in group I. There was no statistical difference between the two groups in terms of flexibility index, complication rates, and blood loss. Neurophysiological changes were not seen in the traction group.
Conclusion: We found the use of IOT is a safe and an effective tool to achieve better correction without an increase in complication rates and blood loss.
Axial traction has been used for centuries to treat spinal deformities either in the form of preoperative or postoperative traction . The first mention of intra-operative traction (IOT) was made by Cotrel et al in 1988 . Since then, there are a few studies on intra-operative traction by various authors [3–13]. The use of traction exploits the viscoelastic properties of musculoskeletal tissues and aids greater deformity corrections when combined with other procedures. The advantage being it requires lesser corrective maneuvers intra-operatively, with less stress on the spinal instrumentation along with a possible rotation of the apical vertebra [6,10], while disadvantages include neuromonitoring changes, and pin tract related complications [14,15]. We believe that intraoperative skull-femoral skeletal traction may effectively assist with spinal deformity correction in neuromuscular scoliosis (NM) and adolescent idiopathic scoliosis (AIS) patients. The primary aim of this study is to find out the effect of IOT in single- stage posterior arthrodesis for AIS and NM on curve correction and the secondary aim is to study its impact on operative time (OR time), intraoperative blood loss, intraoperative neurophysiological (IOM) changes and complications.
A retrospective case-control study was conducted at our center after the approval of the Review Board on scoliosis patients operated from the period of 2010 to 2017 and meeting the inclusion and exclusion criteria. Inclusion criteria of the study were cases of idiopathic scoliosis and neuromuscular scoliosis, preoperative major Cobb angle >50 degrees, and cases involving posterior instrumented stabilization and fusion of the spine (PSIF). Exclusion criteria of the study were preoperative Cobb’s angle <50 degrees, cases involving anterior spinal instrumentation, congenital and syndrome scoliosis, and cases of growth-friendly surgeries.
Group I included cases with the use of IOT, while group II
included cases without the use of IOT. Radiographs along with the
hospital charts were used to gather the necessary information.
Radiographic parameters including preoperative Cobb’s angle
based on anteroposterior (AP) and stretched/bending x-rays
and postoperative Cobb’s angle based on AP x-rays was used
to measure correction index and flexibility index. Correction
index was defined as [magnitude of postoperative cobb’s angle
- magnitude of preoperative upright coronal Cobb’s angle] /
preoperative upright coronal Cobb’s angle while flexibility index
was defined as [magnitude of the side bend/traction Cobb’s
angle-magnitude of the preoperative upright coronal Cobb’s
angle] /preoperative upright coronal Cobb’s angle. Demographic
information along with surgery-related information including
operative time (OR time), intraoperative blood loss, intraoperative
neurophysiological (IOM) changes and complications were
derived from the hospital charts.
During PSIF, intraoperative traction was applied with
Gardner Wells tongs cranially and either skeletal or skin traction caudally. Weights applied in 5 lb increment every 5 minutes with
maximum weight not more than 15% of the bodyweight at the
head end and each limb ensuring no neuromonitoring changes
after each increment. In cases with pelvic obliquity, maximum up
to 20% of the bodyweight on the higher side, 10% on the lower
side. To accommodate the time taken from the application of
traction, OR time was calculated from the time when the patient
was ready after anesthesia. Intraoperative neurophysiological
monitoring (IOM) was conducted in the form of somatosensory
and transcranial motor evoked potentials (SSEP and MEP) by a
trained neurophysiologist in all cases. Apical facetectomy was
performed in all cases to aid correction and fusion. All radiological
and clinical parameters were measured by a trained clinical fellow
and confirmed by a senior staff surgeon. A two-tailed student
t-test of significance will be used for comparing means of each
quantitative data between the two groups, while qualitative
data was compared with help of Chi-Square test and Odds ratio
was obtained with Mantel-Haenszel common odds estimate.
Significance was defined as p< 0.05.
Orthostatic headache is the characteristic feature of
intracranial hypotension which was absent in our case. In the presence of preexisting hydrocephalus, MRI findings did not show
the classical features of intracranial hypotension. High suspicion
of dural tear should be kept in mind, especially in the presence
of headache following spinal surgery with evidence of RCH.
Persistently increased drain volume should alert the surgeon
regarding this possibility. Clamping or removal of the suction
drain often result in significant improvement. Early diagnosis
could significantly reduce the morbidity in such cases. Our case
is interesting as the associated arrested hydrocephalus acted as a
red herring in delaying the diagnosis.
Group I consisted of 35 patients with a mean follow-up of 2.5
years (range 9 months to 6.3 years) and group II had 58 patients
with a mean follow-up of 2.11 years (range 6 months to 6.6
years). On further subdivision based on etiology, group I had 26
patients with AIS and 9 with NM scoliosis, while group II had 52
patients with AIS and 5 NM scoliosis. Seven cases of AIS cases had
a thoracoscopic release (2 in group I and 5 in group II). None of
the NM cases had anterior release. As per the Lenke classification,
group I had 15 cases classified as type I, 3 cases as type III, 2 cases
as type V, 6 cases as type VI while group II 29 cases classified as
type I, 7 cases as type II, 7 cases as type III, 7 cases as type IV, 2 cases
as type V. The mean preoperative Cobb angle on standing x-rays,
stretch x-rays and bending x-rays was 79.29° (range 55 to 122°),
45.25° (range 21 to 65°) and 48.35° (range 36 to 64°) respectively
for group I while for group it was 69.38°(range 51 to 104)°,
45.35° (range 14 to 88°) and 44.58° (range 8 to 86°) respectively
(Table 1). Although there was a statistically significant difference
between the mean preoperative Cobb angle (p = 0.02), there was
no statistically significant difference between the two groups in
terms of flexibility index (group I - 45.51%, group II – 42.89%,
p = 0.45), which suggests that the two groups were comparable
in terms of preoperative flexibility. The groups were further
subdivided based on the etiology into AIS and NM (Table 2).
In cases of AIS, the correction index was 79% in group I vs
66% in group II which was statistically significant better in favor
of traction group (p = 0.01). In the case of NM scoliosis, correction
index was 73% in group I vs 72% in group II, with no statistically
significant difference between the groups (p = 0.93). We found
that the correction index was 11.1% more (p-value <0.05) in
group I compared to group II, seen mainly in the AIS group. Mean
blood loss and operative time were 662 ml (range 205 to 1513ml)
and 7.14 hours (range 4.6 to 9.2 hours) in group I, while 647 ml
(range 170 to 2200 ml) and 6.04 hours (range 4.1 to 10.2 hours) in
group II (Table 2). Operative time was significantly more in group
I (p = 0.01). Group I had 1 case of a dural leak which was sealed.
Group II had 1 case of screw migration which was revised, 2
cases of dural tears which were sealed, 1 case with intraoperative
neuromonitoring changes which returned to baseline, and 1 case
of implant prominence which was revised at 3-year follow-up.
There was no statistical difference between the two groups in
terms of complication rates, and blood loss (Table 1).
Axial traction has been used for centuries to treat spinal
deformities either in the form of preoperative or postoperative
traction . The first mention of intra-operative traction (IOT) was
made by Cotrel et al in 1988 . Since then, there are a few studies
on intra-operative traction by various authors [3–13]. The aims
to find out the effect of IOT in single-stage posterior arthrodesis
for AIS and NM on perioperative outcomes and overall, on health
In this study, we found that the correction index was 11.1%
more (p-value <0.05) in the traction group compared to the group with no intraoperative traction. Comparing based on the etiology,
correction index was 13.4 % (p-value <0.05) more in idiopathic
scoliosis in group I, while there was no significant difference
in cases of neuromuscular scoliosis in both groups. This was
considering that the preoperative flexibility index was comparable
in both groups, suggesting that the traction benefitted in achieving
better curve correction, especially in idiopathic scoliosis. Previous
studies assessing the use of intraoperative skull femoral traction
with AIS patients do not mention the flexibility index and therefore
it cannot be concluded if the two groups were comparable in
terms of their preoperative flexibility [5,10,11,14,16]. Few studies
have reported better curve correction with traction [6,9,10],
while others have reported no difference in the curve correction
In terms of blood loss, our study did not show any significant
difference between the two groups. The mean blood loss was 662
ml in the traction group compared to 647 ml in the group with no
traction. In a study by Da Cunha et al. , reported blood loss of
1485 ml (range 483–3003 ml) in the traction group compared to
2083 ml (range 839–7130 ml). Although there was significantly
less blood loss in the traction group in that study, it is much
more than the blood loss reported in this study. Also, that study
mentions >70% pedicle screw construct, while in this study a
standard pedicle screw construct with transverse process hooks
in the most cephalad level was performed in all cases. In this study,
the mean OR time was significantly higher in the traction group
compared to the no traction group (7.14 hours vs 6.04 hours),
which is contrary to the finding in a similar study in the literature
. Although the study by Keeler et al.  reported less blood loss
and OR time with traction, they have compared between posterior
approach vs anterior and posterior approach, while the current
study has all cases with a posterior approach.
Traction related complications are rare as reported in the
literature [4,5]. In the study by Lewis et al. , the application
of traction led to changes in motor evoked potentials (MEPs) in
more severe and stiff AIS curves. In these patients, MEP changes
responded immediately by decreasing or removing the traction
weight and as a result, there were no long-term permanent
neurologic damages. The traction protocol in that study was
approximately 20% of body weight (to a maximum of 15 lb)
through the Gardner-Wells tongs and 50% of body weight (to
a maximum of 65 lb) evenly distributed between the bilateral
femurs was used. In this study, there were no traction related
complications and protocol used was an application of weight in
5 lb increment every 5 minutes with maximum weight not more
than 15% of the bodyweight at head end and each limb ensuring
no neuromonitoring changes after each increment. In the case of
pelvic obliquity, maximum up to 20% of the bodyweight on the
higher side, 10% on the lower side.
The strength of the study is use of a standard traction protocol
for all patients. Secondly, both groups were matched in terms of
preoperative flexibility and comparison was made with similar pedicle screw construct performed with a posterior approach
making both groups comparable preoperatively. The weaknesses
of this study include it is a retrospective analysis, a relative low
number of patients with NM scoliosis and data includes surgeries
by two surgeons with different correction techniques.
Intraoperative traction is a safe and an effective tool which
gives better curve correction in cases of AIS and NM scoliosis
without causing any significant impact on the blood loss or
traction related complications like neuromonitoring changes or
pin tract infections.
Al Sayegh, Samir JLaMotheML (2013) Intraoperative skull femoral traction (ISFT) in posterior instrumentation for adolescent idiopathic scoliosis: Safety and effect on perioperative care. Can J Surg 56: S54-S55.