Spine (Phila Pa 1976) 2011 (Aug 15); 36 (18): 1427–1437
Senna, Mohammed K. MD; Machaly, Shereen A. MD
Shereen A. Machaly, MD,
Rheumatology and Rehabilitation Department,
Mansoura Faculty of Medicine,
Mansoura University, Mansoura, Egypt
This new, single blinded placebo controlled study, conducted by the Mansoura Faculty of Medicine, conclusively demonstrates that maintenance care provides significant benefits for those with chronic low back pain.
Egyptian Study Shows Maintenance Care Helpful in Chronic Low Back Pain Treatment
FROM: Health Insights Today
In the first study of its kind, researchers at the Rheumatology and Rehabilitation Department at the Faculty of Medicine at Mansoura University in Egypt conducted a prospective single blinded placebo controlled study to assess the effectiveness of spinal manipulation therapy (SMT) for the management of chronic non-specific low back pain (LBP) and to determine the effectiveness of maintenance SMT in long-term reduction of pain and disability levels associated with chronic low-back conditions after an initial phase of treatments.
The investigators noted that numerous clinical trials have attempted to evaluate its effectiveness for different subgroups of acute and chronic LBP but the efficacy of maintenance SMT in chronic non-specific LBP has not been studied.
Actually, the effect of Maintenance Care/Preventive Care SMT on chronic
LBP was explored by Descarreaux (JMPT 2004) in a virtually identical study]
Sixty patients with chronic, nonspecific LBP lasting at least 6 months were randomized to receive either
(1) 12 treatments of sham SMT over a one-month period,
(2) 12 treatments, consisting of SMT over a one-month period, but no treatments for the subsequent nine months, or
(3) 12 treatments over a one-month period, along with “maintenance spinal manipulation” every two weeks for the following nine months.
To determine any difference among therapies, they measured pain and disability scores, generic health status, and back-specific patient satisfaction at baseline and at 1-month, 4-month, 7-month and 10-month intervals. Results were as follows: patients in second and third groups experienced significantly lower pain and disability scores than first group at the end of 1-month period (P = 0.0027 and 0.0029 respectively). However, only the third group that was given spinal manipulations during the follow-up period showed more improvement in pain and disability scores at the 10-month evaluation. In the no maintained SMT group, however, the mean pain and disability scores returned back near to their pretreatment level. Other key findings were that (a) after 1 month, both the SMT and SMT+Maintenance care cohorts showed a significant improvement in spinal flexion and bending, and (b) after 10 months, the SMT+Maintenance care cohort alone showed significant improvements in both spinal flexion and bending and the global assessment scale.
The authors concluded that spinal manipulation is effective for the treatment of chronic nonspecific LBP and that to obtain long-term benefit for the patient, this study suggests maintenance spinal manipulations after the initial intensive manipulative therapy can provide that additional benefit.
Study Design: A prospective single blinded placebo controlled study was conducted.
Objective : To assess the effectiveness of spinal manipulation therapy (SMT) for the management of chronic non-specific low back pain (LBP) and to determine the effectiveness of maintenance SMT in long-term reduction of pain and disability levels associated with chronic low-back conditions after an initial phase of treatments.
Summary of background: SMT is a common treatment option for low back pain. Numerous clinical trials have attempted to evaluate its effectiveness for different subgroups of acute and chronic LBP but the efficacy of maintenance SMT in chronic non-specific LBP has not been studied.
Subjects and Methods: 60 patients with chronic, nonspecific LBP lasting at least 6 months were randomized to receive either:
(1) 12 treatments of sham SMT over a one-month period,
(2) 12 treatments, consisting of SMT over a one-month period, but no treatments for the subsequent nine months, or
(3) 12 treatments over a one-month period, along with "maintenance spinal manipulation" every two weeks for the following nine months.
To determine any difference among therapies, we measured pain and disability scores, generic health status, and back-specific patient satisfaction at baseline and at 1-month, 4-month, 7-month and 10-month intervals.
Results: Patients in second and third groups experienced significantly lower pain and disability scores than first group at the end of 1-month period (P = 0.0027 and 0.0029 respectively). However, only the third group that was given spinal manipulations during the follow-up period showed more improvement in pain and disability scores at the 10-month evaluation. In the no maintained SMT group, however, the mean pain and disability scores returned back near to their pretreatment level.
Conclusion SMT is effective for the treatment of chronic non specific LBP. To obtain long-term benefit, this study suggests maintenance spinal manipulations after the initial intensive manipulative therapy.
From the FULL TEXT Article:
Low back pain (LBP) is one of the most common musculoskeletal
ailment worldwide. It affects up to 80% of
the adult population at some point during their lives. 
A simple and practical classification, divided LBP into three
main categories, the so-called “diagnostic triage” : specific
spinal pathology, nerve root pain/radicular pain and nonspecific LBP. Chronic LBP is defined as LBP persisting for at
least 12 weeks.  “Nonspecific” chronic LBP is the LBP that is
not attributable to a recognizable, known specific pathology
(such as infection, tumor, osteoporosis, fracture, structural
deformity, inflammatory disorder, for example, ankylosing
spondylitis, radicular syndrome, or cauda equine syndrome).
Nonspecific LBP represents about 85% of LBP patients seen
in primary care.  About 10% will go on to develop chronic,
disabling LBP.  It is this group of LBP that uses the majority
of health care and socioeconomic costs. [6, 7]
Many reviews evaluated the role of spinal manipulation
(SM) as a treatment of LBP. The majority of these reviews
concluded that SM is an efficacious treatment for nonspecific
LBP. [8–13] However, most reviews restricted their positive conclusions
to patients with acute nonspecific LBP. Some studies
suggest that patients with chronic nonspecific LBP are likely
to respond to SM.  A recent high quality review of literature
stated that Cochrane review found SM moderately superior
to sham manipulation for chronic LBP.  However, research
evidence,  recognizes that not all patients with LBP should be
expected to respond to a manipulation intervention. Thus, the
debate whether or not SM constitutes an efficacious treatment
Most of the studies concerned about the therapeutic effects
of SM investigated theses effects only for short term. One
possible way to reduce the long-term (<6 months) effects of
LBP is maintenance care (or preventive care).  In a previous
study, manipulated patients with chronic nonspecific LBP had
improved within 2 weeks and after this time, new cases of
improvement occurred for every visit, and at the 12th visit,
approximately 75% of the patients had improved.  Another
study found that the thrust manipulation-treated group of patients
showed the best outcome compared with the no manipulation
and nonthrust manipulation patients with improved
pain and 66% reduction in Oswestry scores over a period of
4 sessions and by the end of 12 sessions further improvement
was obtained.  This raises the question if, the more the sessions
offered the greater the improvement achieved, so it is
hypothesized that if spinal manipulation therapy (SMT) can
be maintained for longer periods, it will be more beneficial in
maintaining the desirable outcomes obtained after short-term
treatment. However, studies investigating the role of maintained
manipulation in reducing pain and disability associated
with chronic nonspecific LBP are lacking. To the best
of our knowledge, no one had searched this concept except
one study of Descarreaux et al  who reported the positive
effects of continued manipulation treatment in maintaining
functional capacities and reducing the number and intensity
of pain episodes after an acute phase of treatment.
The goal of this study was to assess the effectiveness of
SMT for the management of chronic nonspecific LBP and to
determine the effectiveness of maintenance SMT in long-term
reduction of pain and disability levels associated with chronic
low back conditions after an initial phase of treatments.
MATERIALS AND METHODS
Eligible subjects were patients aging between 20 and 60
years with chronic nonspecific LBP (that lasted for at least 6
months). A total of 154 patients were examined, 61 patients
were excluded whereas 93 patients were eligible and enrolled
in this study. Patients with “red flags” for a serious spinal
condition (e.g. , tumor, compression fracture, infection), signs
consistent with nerve root compression (i.e. , positive straight
leg raise >45 ° , or diminished reflexes, sensation, or lower
extremity strength), structural deformity, spondylolithesis,
spinal stenosis, ankylosing spondylitis, osteoporosis, prior
surgery to the lumbar spine or buttock, obvious psychiatric
disorders, referred pain to the back, widespread pain (e.g. , fibromyalgia), obese patients, current pregnancy, patients older
than 60 years or younger than 20 years, and patients who had
previous experience with SMT were excluded.
All patients were recruited from the Outpatient Clinics of
Rheumatology and Rehabilitation Department in Mansoura
University Hospital , which is one of the major university hospitals,
treating large number of patients with different causes
of LBP in a specialized outpatient clinic dedicated for back
pain. The physicians conducting the trial are MD certified,
well-trained, have been in practice for more than 10 years
with good experience in managing LBP, and they are staff
members of Rheumatology & Rehabilitation Department,
All patients underwent a standardized baseline evaluation
before treatment consisted of detailed history taking and
physical examination. Subjects were asked to identify the
mode and date of onset of their LBP. Also, patients were asked
for present symptoms suggestive of specific spinal disease,
prior back therapy (including manipulation or surgery), or
prolonged use of corticosteroids. All patients underwent local
musculoskeletal examination as well as full neurologic examination.
Blood sample was withdrawn from every patient and
sent to the laboratory for complete blood count, erythrocyte
sedimentation rate, and C-reactive protein analysis. Lateral
and anteroposterior radiograph films followed by magnetic
resonance imaging of the lumbar spine were also taken in an
attempt to rule out the specific diseases of the lumbar spine.
Group Classification and Procedures
After the baseline evaluation, the eligible patients were
assigned randomly to one of three groups matched for age
and sex. The study was initially designed to include three
groups; the first (control) group comprises more patients than
the other two groups as we presumed that patients who may
not complete the trial will mostly belong to this group. It was
planned to randomize 40%, 30%, and 30% of patients to the
first, second, and third groups, respectively. Patients allocation
is shown in Figure 1.
of participants through the trial.
Randomization was performed using sequential-sealed
envelopes prepared before enrollment of the patients. Patients
were randomized twice, first for the treating clinician and second
for the treatment group. Then, first envelope was opened,
and only the treating fellow subsequently opened the sealed
second envelope and recorded the allocation of patients as
they entered the trial. Patients who were manipulated by one
physician were assessed throughout all the trial follow-up
intervals by the other physician who was completely blind
to group assignment of patients being assessed. Patients were
not allowed to talk about the type of care they received.
After randomization patients started the first phase treatment
(1-month period). During this phase, all participants are
informed about back instructions and received 12 sessions
of manipulation (or sham manipulation) followed by back
exercise in form of pelvic tilt range of motion (ROM) exercise.
The first group (age range: 21–53 years) received 12 treatments
consisting of sham SM using minimal force over a
1-month period (control group), but no treatments for the
subsequent 9 months. The second group (age range: 23–48
years), received 12 treatments consisting of standardized SM
three times weekly over a 1-month period, but no treatments
for the subsequent 9 months (nonmaintained SMT group).
The third group (age range: 20–50 years), also received same
intensive treatment of SM as second group over a 1-month period
“initial intensive SMT,” along with “maintenance SMT”
every 2 weeks for the next 9 months (maintained SMT group).
Subjects in second and third groups received the same manipulation
technique. SM is defined as a high velocity thrust
to a joint beyond its restricted range of movement. 
The manipulation technique is performed with the patient
supine. The side to be manipulated first will be the
more symptomatic side on the basis of the patient’s complaint
followed by manipulation of the opposite side. If the
patient cannot specify a more symptomatic side, the therapist
may select either side for manipulation. The therapist
stands on the side opposite of that to be manipulated. The
patient is passively moved into side-bending toward the
side to be manipulated (the patient will lie with the more
painful side up). The patient interlocks the fingers behind
his or her head. The therapist passively rotates the patient,
and then delivers a quick thrust to the anterior superior
iliac spine in a posterior and inferior direction. If a pop
sound occurred, the therapist will proceed to instruct the
patient in the ROM exercises. If no pop is produced , the
patient will be repositioned and the manipulation will be
attempted again (a maximum of two attempts per side was
permitted). If no pop sound is produced after the second
attempt, proceed to instruct the patient in the pelvic tilt
ROM exercises. 
Sham manipulation included SM techniques, which
consisted of manually applied forces of diminished magnitude,
aimed purposely to avoid treatable areas of the spine
and to provide minimal likelihood of therapeutic effect. 
Patients in all treatment groups will be instructed in
a pelvic tilt ROM exercise after manipulation (or sham
manipulation). Subjects are asked to lie on their back and
bend the hips and knees so that their feet are fl at on the
surface. Subjects then attempt to flatten their back on the
table by slightly “drawing in” their stomach and rotating
the hips backward. The motion is to be performed in
a pain-free range. Subjects will be instructed to perform
10 repetitions after each manipulation and 10 repetitions
3 times daily on the days they did not attend the session.
Pelvic tilt aimed to increase the fl exibility of the lower
back and pelvis.
The primary endpoint was the patient’s self-evaluation of their
disability status by use of the Oswestry disability questionnaire
after maintained SMT for 10-month period (Table 1) .
Outcome measures included:
(1) Subjective Patient-Based Assessments: They are increasingly being used to evaluate the outcome of LBP.  Patients
completed the following questionnaires at baseline, and
at 1-, 4-, 7-, and 10-month periods:
(a) Disease-specific: The Oswestry disability questionnaire
was used as a LBP-specific functional assessment.  It
has been shown to be a valid indicator of disability in patients
with LBP. The questionnaire consists of 10 items addressing
different aspects of functional capacities. Each item
is scored from 0 to 5, with higher values representing greater
disability. The total score is multiplied by 2 and expressed as
(b) Pain levels were assessed on a visual analog scale (VAS):
The VAS consisted of a continuous 100-mm scale. Patients
were told that one end of the VAS (0) referred to no pain and
the other end (100) referred to the worst pain, and they were
asked to mark the level of their pain. VAS is a valid tool to
indicate the current intensity of pain. 
(c) Generic instruments: 36-Item Short Form Health
Survey (SF-36) was used. This is a 36-item general health
questionnaire that measures eight dimensions: general health
perception, physical function, physical role, bodily pain, social
functioning, mental health, emotional role, and vitality.
The SF-36 is a valid and reliable instrument widely used to
measure generic health status, particularly for monitoring
clinical outcomes after medical interventions. 
(d) Patient’s global assessment of outcomes: Assessed by
asking the patients to compare their current back-related
health status with their baseline status, with the following
choices: (i) much better; (ii) somewhat better; (iii) mostly the
same; (iv) somewhat worse; and (v) much worse. This five
level instrument has a score range 1 to 5 (best to worse).
(2) Objective Measure: Mobility tests are widely used as
an objective measure in patients with LBP. The participants
underwent two mobility tests: the modifi ed Schober test  and
the lateral bending measurement.
Partial blindness of the participants was established, we
planned at the study design not to tell the enrolled patients to
which treatment group they were randomly assigned, but as the
maintained SMT group could be easily discriminated especially
in the second phase of the trial, we tried to minimize the risk
of bias and overcome this difficulty, by blinding participants to
the study hypothesis. Partial information given to our participants
consisted of not informing them about the existence of
a placebo, participants were aware that different procedures
were being compared but not that one treatment was a control.
Thus, participants could reasonably expect an improvement
regardless of treatment received. To overcome the difficulties
in maintaining blinding of participants in the phase of maintenance,
participants in the maintained SMT, and control arms
did not attend treatment and assessment concurrently and both
are not informed about the purpose of the study.
The local ethical committee had approved this work.
An informed consent was taken from each patient before
enrollment in the study.
Subjective and Objective
Outcome Measures at Baseline
All statistical analyses were performed using SPSS for windows
version 17.0 (SPSS, Chicago, IL). Continuous data (age
and duration of LBP) obtained at baseline were expressed as
mean ± SD and compared between each two groups using
Student t test. Sex (categorical data) was expressed in number
and percent and compared using the χ2 test. The outcome
measures were obtained for fi ve different time intervals (baseline,
after the first month, and each 3 months in the follow-up
periods). The outcome measures between each two groups at
the end of the first phase were compared using Student t test.
During second phase, we compared the outcome measures
among the groups at the end of 4th, 7th, and 10th months.
Statistical signifi cance was set at P < 0.05.
Cases with missing values pose an important challenge in
this study. Five patients (of the 93 patients who underwent the
baseline evaluation) withdraw during the first phase before the
start of the sessions. The remainder 88 patients were evaluated
at baseline, entered the subsequent sessions and had completed
the phase-1 treatment and then revaluated at the end of
phase 1. Of these 88 patients, 80 patients were evaluated at
the 4th month, 71 patients at 7th month, and 60 patients at
the 10th month. Simply discarding these cases , by the method
of listwise deletion, could render our analysis inaccurate.
Multiple imputation is a statistical technique for handling and
analyzing incomplete data sets, that is, data sets for which
some entries are missing. The purpose of multiple imputation
is to generate possible values for missing values, thus creating
several “complete” sets of data. Application of the technique
requires three steps: imputation, analysis, and pooling.
In our study, the variables containing the missing data are
operated to generate five complete data sets other than the
original dataset (imputation step). The five complete data sets
are computed and analyzed (analysis step). The results of the
analyses are provided and a “pooled” output that estimates
what the results would have been if the original dataset had
no missing values (pooling step). These pooled results are generally
more accurate than those provided by single imputation
methods. The pooled data were analyzed using standard
procedures (mean, standard error of mean, and the Student
Comparison Among the Three Groups
Despite the three groups of patients were similar at baseline
evaluation (Tables 1 and 2), patients in the second and third
groups experienced significantly lower pain and disability
scores compared with the control group after the first phase of
treatments, that is, after 1-month period. By the end of second
phase of treatment (after 10-month period), patients with maintained
SMT had significantly lower pain and disability scores
compared with the patients of the nonmaintained SMT group.
Change of VAS Pain Score During the 10-Month Period
The initial phase of treatment yielded a reduction of 12.35
and 13.36 mm in the second and third groups, respectively,
whereas it is reduced only by 8.03 mm in the control group on
the pain scale (Table 3). At the 4- and 7-month evaluation the
mean pain score gradually elevated back toward the pretreatment
level in the nonmaintained SMT group. However, pain
score in the maintained SMT group continued improving
(Tables 4 and 5). By the end of the study, pain score yielded a
reduction of 19.26 mm in the maintained SMT group whereas
it is returned near to the pretreatment level in the group of patients
who discontinued their therapy interventions (Table 6 and Figure 2)
Demographic and Baseline
Characteristics for all Subjects
Subjective and Objective
Outcome Measures at the End of
1-Month (Phase 1)
Subjective and Objective
Outcome Measures at 4 Months
Subjective and Objective
Outcome Measures at 7 Months
Subjective and Objective
Outcome Measures at the End of
10 Months (Phase 2)
Pain score (VAS) over
the 10-month period.
Change of Oswestry Disability Score
A greater difference, however, was seen in disability scores
over the duration of the study. By the end of first phase, SMT
significantly reduced the disability score in nonmaintained
SMT group and maintained SMT when compared with the
control group ( P = 0.005 and 0.007, respectively). Analysis
of the data after the 10-month period showed that while the
disability score of the patients in the nonmaintained SMT
group returned back nearly to their pretreatment level, the
score was significantly lower in patients who received maintenance
SMT compared with the nonmaintained SMT group
( P < 0.001). In the maintained SMT group, the disability
score is reduced by an average of 18.98 points lower than
baseline level (Table 6 and Figure 3). At the 4- and 7-month
evaluation, the mean disability score gradually elevated back
toward the pretreatment level in the nonmaintained SMT
group. However, disability score in the maintained SMT
group continue improving.
Score (%) over the 10-month period.
Change of SF-36 Score
SF-36 questionnaire showed significantly better outcome
after 1-month period for both the second and third groups
compared with the control group (Table 3), this continued
to improve during the second phase only for the maintained
SMT group whereas the nonmaintained SMT group showed
progressively reducing SF-36 score (Tables 4 and 5). By the
end of the second phase, there was significant difference in
the score between the maintained and nonmaintained groups
Change of Spinal Mobility
Measurement of spine flexion and lateral bending yielded increase
in their ROM in the maintained SMT group in the first
phase and continued to increase in the second phase, whereas
in the nonmaintained SMT group the spinal movement increased
in the first phase only and decreased to near the pretreatment
level by the end of the second phase.
Patient’s Global Assessment of Outcomes
The patient’s global assessment of outcomes was obtained at
the end of phase 2 (at the 10-month evaluation) from the 60
patients who had completed the treatment program. Patient’s
global assessment scale is significantly better in the maintained
SMT compared with nonmaintained SMT and control
groups (P = 0.015). On the one hand, in the maintained SMT,
13 (65%) patients reported better outcome (scores 1 and 2) at the end of the treatment program compared with only 7 (35%) and 6 (30%) patients reporting better outcome in the
nonmaintained SMT and control groups, respectively. On the
other hand, only three (15%) patients in the maintained SMT
reported worse outcome (scores 4 and 5) compared to six
(30%) and nine (45%) patients in the nonmaintained SMT
group and control groups, respectively.
Interestingly, the most common adverse effects reported in
this study were local discomfort and tiredness but no serious
complications were noted. Most adverse effects were transient
and began with 24 hours after treatment and were of
mild to moderate severity.
This study confirms previous reports showing that SM is an effective
modality in chronic nonspecific LBP especially for shortterm
effects. [30–37] As the disability and pain scores in our study
are significantly reduced in the short-term evaluation — but not
in long-term — when compared with the sham manipulation.
The current study also evaluated the effects of maintained
SMT in maintaining levels of pain and functional capacity
gained after an initial phase of treatment. VAS pain and
Oswestry Disability Score remained at the better posttreatment
levels only for the group with maintained SMT whereas
VAS of pain and Oswestry Disability Score returned to their
pretreatment levels for the nonmaintained SMT group.
We designed this trial to deliver SMT in three sessions
weekly, then bimonthly in the second phase. One query that
had to be investigated is the frequency of the sessions and the
intervals between sessions. The observations from previous
literature can make us suppose that the unsatisfactory finding
during follow-up may be attributed to widely separated
manipulation sessions as the trials in which increased numbers
of SMT sessions were applied, obtained better outcome
in short-term, and continued for sometime after stoppage of
treatment, than the trials used less numbers of sessions. For
example, on the one hand, studies that applied 12 18 or 10 sessions  during 6-week therapy period found that SMT resulted
in greater short-term pain relief and disability reduction.
On the other hand, studies in which lesser number of sessions
over longer treatment period were offered, achieved either
mild to slightly moderate benefit on short-term only  (eight
sessions over 12 weeks) or no benefits over sham treatment
(seven sessions over 5 months).  However, further researches
are needed to find out the optimum frequency and number of
the sessions offered to obtain and maintain the best desirable
Only sham-controlled studies in which the control intervention
mimicked SM can tell us whether the clinical outcomes
of SM are due to specific or nonspecific (e.g. , placebo)
effects.  So, we enrolled in our study sham SMT in comparison
to thrust manipulation and our finding of effectiveness
of manipulation versus a sham procedure, agreed with other
studies showing that SMT had more short-term pain and disability
reduction than sham SMT. [34, 40]
An important issue to be discussed is the state of blindness
in the current trial. Partial blindness of the participants
was established, by blinding participants to the study
hypothesis. Blinding participants to the study hypothesis was
proposed either with the use of a sham procedure or when
participants and/or health care providers could not be blinded
to the treatment they received.  Wood  showed that lack
of blinding yielded exaggerated treatment effect estimates
for subjective outcomes but had no effect on objective
outcomes. We included in our trial the main domains of
patient-based outcomes recommended for evaluating the
treatment of spinal disorders  and, additionally, we assessed
spinal mobility as an objective outcome to support the
The disability score difference (>14 points) observed after
10 months in current study between the maintained SMT
group and nonmaintained SMT group is statistically significant and clinically important. Fritz and Irrgang  showed that
a six-point difference in the Oswerstry Questionnaire was the
minimal clinically important difference. This six-point difference
is the amount of change that distinguishes between
patients who have improved and those who remained stable.
The postulated modes of action of SMT include disruption
of articular or periarticular adhesions, improve of trunk
mobility,  relaxation of hypertonic muscle by sudden stretching,
release of entrapped synovial folds or plica, attenuation
of α-motor neuron activity, enhancement of proprioceptive
behavior, and release of β endorphins, thus increase pain
threshold.  These mechanisms are expected to sustain during
maintenance of SMT.
The major limitation of the current study is the missing
data from patients who declined to follow-up at different intervals
of the study. The method for handling missing data by
“listwise deletion” will generally be biased because this method
deletes cases that are missing any of the variables involved
in the analysis. Moreover, as deletion of incomplete cases
discards some of the observed data, complete-case analysis
is generally ineffi cient as well, that is, it produces inferences
that are less precise than those produced by methods that use
all of the observed data. We tried to deal with this situation
by using special statistical technique, “multiple imputation”
that is applied for handling and analyzing incomplete data
sets, that is, data sets for which some entries are missing. Imputation
is a more appropriate approach to handling nonresponse
on items for several reasons. First, imputation adjusts
for observed differences between item nonrespondents and
item respondents; such an adjustment is generally not made
by complete-case analysis. Second, imputation results in a
completed data set, so that the data can be analyzed using
standard software packages without discarding any observed
values.  Experience has repeatedly shown that multiple
imputation tends to be quite reasonable method for replacing
missing values. It has been shown that by using proper
method to create imputations, the resulting inferences will be
statistically valid and properly reflect the uncertainty because
of missing values. For proper imputation the application of
the technique requires three steps: imputation, analysis, and
pooling.  The SPSS version 17 program used in this study
fulfi ll these three requirements. The technique application is
mentioned in details under the statistical analysis section.
We delivered maintained therapy to patients in this study
for 10 months, which proved efficacy in terms of reducing
pain and disability, but whether this gained effect will last and
for how long is an issue that should be investigated and discussed
in further longitudinal studies with attempts made to
prolong the intervals gradually between sessions with more
prolonged follow-up after treatment. However, as patients
did benefit from the maintenance treatments, we believe that
periodic patient visits permit proper evaluation, detection,
and early treatment of any emerging problem, thus preventing
future episodes of LBP.
Future researches must focus on for how long SMT should
be maintained and when to stop it without relapse of pain
and how often frequency rate of sessions is helpful. Larger
further studies may be carried out to put answers and deduct
SMT is effective for the treatment of chronic nonspecific LBP.
To obtain long-term benefit, this study suggests maintenance
SM after the initial intensive manipulative.
This study demonstrated that SMT is an effective modality in chronic nonspecific
LBP for short-term effects.
Application of SMT yielded better results when compared with the sham manipulation.
We suggest that maintained SM is beneficial to patients of chronic nonspecific LBP
particularly those who gain improvement after initial intensive manipulation to
maintain the improved posttreatment pain and disability levels.
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