neck pain is one of the most common health problems in the general population , particularly 
 among people of working age . the prevalence of neck pain has generally been reported to be 
 4554% and approximately 50% for workers1 , 2 ) . related to this , approximately 25% of out - patient 
 physical therapy visits concern presentations of pain in the neck region3 , 4 . furthermore , over 33% of neck pain patients develop chronic symptoms5 and the economic expense associated with chronic mechanical 
 neck pain is very high6 . the source of mechanical neck pain is related to various pain - sensitive structures , 
 including the zygapophyseal joints , ligaments , muscles , uncovertebral joints , intervertebral 
 discs , or neural tissues around the cervical spine7 . additionally , it can be related to mechanical dysfunction of the 
 cervical spine8 , which results in reduced 
 neck mobility7,8,9 . treatment of mechanical neck pain includes medication and physical therapy such as 
 traction , massage , and other physical interventions , including spinal 
 manipulation / mobilization . the aim of treatment is to reduce pain and to increase range of 
 motion of the cervical spine . however , complications with this technique have been 
 reported , particularly risk of vertebro - basilar artery insufficiency after cervical 
 manipulation12 . for this reason , it has 
 recently been suggested that thoracic spine manipulation and mobilization could reduce 
 symptoms of mechanical neck pain in patients , but with fewer complications13 . recent studies have shown that performing thoracic spine manipulations ( multiple levels ) on 
 mechanical neck pain patients can result in immediate improvements in symptoms and neck 
 function13,14,15 . it has been found that 
 thoracic spine manipulation can activate descending inhibitory mechanisms resulting in 
 hypoalgesia in distant areas , and may restore normal biomechanics of the thoracic region , 
 potentially lowering mechanical stress and increasing the distribution of joint forces in 
 the cervical spine15 . additionally , 
 cleland et al . also suggested that multiple thoracic mobilization grade iii could reduce 
 pain and disability in the neck13 . it was 
 claimed that the t6 vertebral level was the most rigid in terms of nervous system 
 mobility16 . therefore , performing 
 single manipulation or mobilization at this level may improve symptoms in chronic neck pain 
 patients . that is , evidence exists to support the use of thoracic manipulation for reduction 
 of pain and for increasing cervical range of motion ( crom ) . however , previous studies have 
 not provided evidence on the effects of single level thoracic manipulation and mobilization 
 in patients with chronic neck pain . furthermore , it is not known whether thoracic mobilization 
 produces similar treatment outcomes to thoracic manipulation . finally , there is little 
 evidence of outcomes of either treatment beyond immediate follow - up sessions ; for example , 
 24 hours , after performing single level thoracic manipulation or mobilization . therefore , this study aimed to investigate and compare the immediate and extended 24 hour 
 effects of single level thoracic manipulation and mobilization in subjects with chronic neck 
 pain . it was hypothesized that : 1 ) single level thoracic manipulation would reduce pain at 
 rest and increase crom in mechanical neck pain patients , similar to multi - level 
 manipulation ; 2 ) single level thoracic mobilization would also reduce pain at rest and 
 increase crom but to a lesser extent than manipulation due to inhibitory mechanism 
 activation directly associated with the latter modality ; and 3 ) the effects of both thoracic 
 manipulation and mobilization on pain at rest and crom were expected to be apparent in both 
 immediate and 24-hour follow - up . a prospective , assessor - blind , pilot study was conducted at the school of physical therapy 
 laboratory , khon kaen university , thailand . the research protocol was approved by the 
 research ethics committee for human research of khon kaen university . thirty - nine chronic mechanical neck pain subjects were recruited to participate in the 
 current study . subjects presented with unilateral or bilateral pain in the posterior neck 
 and/or shoulder regions , and neck postures , neck movement , or palpation of the cervical 
 region could provoke their symptoms . inclusion criteria were : 1 ) aged 18 to 60  years ; 2 ) a 
 vas pain rating of greater than or equal to 40 points ; and 3 ) symptoms of more than 3 months 
 in duration . subject baseline ratings of neck pain were captured using a 100-point vas with 
 values ranging from 0 to 100 . subjects were excluded if they presented with any of the following : 1 ) diagnosis of 
 cervical radiculopathy or myelopathy ( determined by a physiatrist ) ; 2 ) previous history of 
 cervical and thoracic spine fracture and/or dislocation ; 3 ) previous history of surgery of 
 the cervical and/or thoracic spine ; 4 ) previous history of spinal osteoporosis , spinal 
 infection or fibromyalgia syndrome ; 5 ) previous history of underlying hypertension , heart 
 disease or meningitis ; 6 ) pregnancy ; 7 ) any contraindication to manipulation ; and 8) history 
 of spinal manipulative therapy before this study .   participant flow diagram and follow - up evaluation the study sample size ( n ) was determined using the statistical formula : n = 2 
 ( z/2 + z )  / ( m2- 
 m1 ) . where n is the resulting sample size , z/2 is the 
 standard normal score associated with the acceptable type i error probability , z 
 is the standard normal score associated with the acceptable type ii error probability , 
  is the standard deviation of the target response , and m2 and 
 m1 are condition means for treatment and control groups . the investigators 
 referred to a previous study for mean ratings of pain at rest for the thoracic manipulation 
 and control groups using a vas . means were 15.57.7  mm and 4.24.6  mm , respectively14 . for the sample size determination , we 
 used a significance level of 0.05 (  ) and the power of test was set at 90 percent ( 1- ) . 
 based on these values , it was estimated that 13 subjects should be recruited for each group 
 in the present study . single level thoracic manipulation ( screw thrust technique ) at both zygapophyseal 
 joints of t6-t7 all subjects were examined by a rehabilitation medicine physician . each subject was asked 
 to complete a screening questionnaire in order to ensure they met the inclusion criteria . each subject was required to sign an informed consent form before participating in the 
 study . each subject was randomly assigned to receive single level thoracic manipulation , or 
 single level thoracic mobilization , or to rest in a prone position ( the control group ) using 
 a block randomized allocation with a block size of three . a  who was not involved in the recruitment of the subjects , 
 treatments or evaluation process . subsequently , subject pain level at rest was measured 
 using the vas and cervical range of motion was assessed using a crom measurement device 
 ( fig . demographic information of 
 each subject including age , sex , weight , height and bmi were also collected . single level thoracic mobilization grade iii unilateral postero - anterior mobilization 
 at the zygapophyseal joint of t6-t7 on both the left and right sides the subjects in the single level thoracic manipulation group were asked to lie in a prone 
 position on a standard examination table and they were marked on both sides of the 
 zygapophyseal joint ( t6-t7 ) ( fig . subjects 
 were then instructed to perform deep inhalation and exhalation and at the end of exhalation , 
 a clinician performed thoracic manipulation ( screw thrust technique ) at both 
 zygapophyseal joints of t6-t77 . if a 
 popping sound ( i.e. , release of gas from joint cavities ) was not heard on the first attempt , 
 the subject was instructed to reposition and the same technique was repeated . this procedure 
 was performed for a maximum of two attempts and was completed within 2 minutes13 . it should be noted that clinician c had 
 more than 10  years of experience in manual therapy for treating neck pain patients . the subjects in the single level thoracic mobilization group were asked to lie in a prone 
 position on the examination table and they were marked on both sides of the zygapophyseal 
 joint ( t6-t7 ) ( fig . clinician c then performed 
 grade iii unilaterally postero - anterior mobilization at the zygapophyseal joint of t6-t7 on 
 both the left and right sides for 1 minute7 . the grade iii mobilization involved large amplitude motion at the 
 limit of range of motion . the subjects in the control group were asked to lie in a prone position on the examination 
 table . clinician c placed their hands on both sides of the zygapophyseal joint at t6-t7 
 without compressive pressure on the joints for a total of 2 minutes . subjects in both groups 
 received no other treatment ; for instance , massage or self - manipulation during the research 
 period , except for any usual medicines . the rating scale was a 100-millimeter ( mm ) 
 line with anchors of  no pain  associated with the value of 0 and  worst pain vass have been found to be highly reliable instruments for detecting immediate 
 changes in pain level at rest ( icc = 0.97)17,18,19 . the cervical range of motion was measured using cervical range of motion ( crom ) device 
 ( performance attainment associates , usa ) . prior testing has shown the crom device to be 
 highly reliable with intra - rater reliability ranging from 0.91 to 0.9520 . the crom and subject 's pain level at rest ( vas ratings ) were examined within each group . additionally , comparisons were made between the thoracic manipulation , mobilization and 
 control groups . kolmogorov - smirnov goodness of fit tests were used to test the analysis of 
 variance assumption of normality for the two response data sets . paired t - tests were used to 
 evaluate differences in the crom and pain levels at rest , pre- and post - intervention within 
 groups . an analysis of covariance ( ancova ) was used to identify differences in crom and pain 
 level between groups after adjusting for differences in subject baseline values for each 
 outcome measure . the criterion level of significance for this study yrs = years , m / f = males / females , con = control group , man = single thoracic 
 manipulation group , mob = single thoracic mobilization group * p<0.05 , * * p<0.01 , con = control group , man = single thoracic manipulation group , 
 mob = single thoracic mobilization group forty - two subjects were screened for the study . consequently , 39 patients with chronic mechanical neck pain ( 10 
 males and 29 females ) participated in the study . the mean ( standard deviation ) demographic 
 data for the subjects are shown in table 1 . no 
 differences were found for age , sex , weight , height and bmi between the study groups 
 ( p>0.05 ) . table 2 presents descriptive statistics for all 
 response measures for each subject group collected at pre - test , immediately following 
 treatment and 24 hours after treatment . paired t - test results revealed vas ratings for 
 subjects to significantly decrease for both the thoracic manipulation and mobilization 
 groups ( p<0.05 ) . subjects receiving thoracic manipulation significantly increased in crom 
 in flexion , extension , left and right lateral flexions , and left and right rotations 
 ( p<0.01 ) from baseline . in addition , subjects in 
 the thoracic mobilization group significantly increased in crom in flexion , left and right 
 lateral flexions , and left and right rotations ( p<0.05 ) , but not in extension . there was no significant difference in crom from baseline 
 to post - intervention for the control group . comparison between groups using an analysis of covariance ( ancova ) demonstrated no 
 statistically significant difference in vas ratings post - intervention . regarding neck movement , the crom for the thoracic manipulation 
 group significantly increased in comparison to the control group in flexion , extension , left 
 and right lateral flexion , and left rotation ( p<0.05 ) . the crom for the thoracic 
 mobilization group significantly increased in comparison to the control group in flexion 
 only ( p<0.01 ) , but not in terms of extension and rotation . in addition , the crom for the thoracic manipulation group 
 significantly increased in comparison to the mobilization group in extension and left 
 rotation ( p<0.05 ) ( table 3 ) . * p<0.05 , * * p<0.01 , con = control group , man = single thoracic manipulation group , 
 mob = single thoracic mobilization group * p<0.05 , * * p<0.01 , con = control group , man = single thoracic manipulation group , 
 mob = single thoracic mobilization group results at the 24-hour follow - up demonstrated vas ratings significantly decreased for both 
 treatment groups ( p<0.05 ) . with respect to crom , subjects receiving thoracic manipulation 
 significantly increased in flexion , extension , left and right lateral flexions , and left and 
 right rotations ( p<0.05 ) . furthermore , subjects receiving thoracic mobilization 
 significantly increased in motion in right and left rotational directions ( p<0.05 ) . comparison between groups , using an ancova demonstrated that there was no statistically 
 significant difference in pain at rest between the three groups 24 hours after intervention . the crom in the thoracic manipulation group 
 significantly increased in flexion , left lateral flexion and left rotation in comparison to 
 the control group ( p<0.05 ) . the crom for the thoracic mobilization group significantly 
 increased in flexion and left rotation by comparison with the control group ( p<0.05 ) . there was no significant difference 
 in the crom between the thoracic manipulation and mobilization groups ( table 4 ) . analyses on crom in the extension direction revealed different effects for the treatment 
 groups from pre - testing . the thoracic manipulation group showed a substantial increase in 
 extension ; whereas , the thoracic mobilization and the control groups showed only slight 
 increases at immediate assessment and a decrease after 24 hours for the mobilization 
 group . the results of this study indicate patients with chronic neck pain immediately experienced 
 a significant decrease in pain at rest after receiving thoracic manipulation and 
 mobilization as well as an increase in crom . in addition , observations made 24-hour after intervention indicate that patients 
 with neck pain experienced a significant decrease in pain at rest and an increase in crom in 
 all directions after receiving thoracic manipulation . results also indicated that patients significantly increased in crom in left and 
 right rotation 24 hours after receiving thoracic mobilization . the interventions 
 demonstrated that thoracic manipulation and mobilization results in decreased pain and 
 increased crom in patients with neck pain . data was collected on patients in an acute and sub - acute stages of pain 
 and a multiple level thoracic manipulation technique was used ; whereas , in the current 
 study , data was collected on patients in a chronic stage of pain ( of 3 or more months 
 duration ) and a single level thoracic manipulation was used14 . prior studies employed a combination of thoracic spine thrust 
 manipulation , electro - therapy , and thermal programs in patients with acute mechanical neck 
 pain15 . the neurophysiologic response of pain reduction through thoracic manipulation may be 
 explained in terms of several mechanisms . one possible mechanism is that the manipulation 
 induces a reflex inhibition of pain or muscle relaxation reflex by modifying the discharge 
 of proprioceptive group i and ii afferents . a second mechanism is that the spinal 
 manipulation activates descending inhibitory mechanisms resulting in pain reduction in 
 distant areas from the manipulation . through these mechanisms , the thoracic manipulation may 
 induce ventral periaqueductal gray ( vpag ) in the brain , which activates endogenous opioid 
 peptides resulting in pain reduction in different areas22,23,24,25 . regarding the reduction 
 in pain at rest between baseline ratings and the 24-hour follow - up for the control group , 
 this may have been the results of overall relaxation and psychological change due to 
 physical contact by a clinician26 , 27 . firstly , the thoracic manipulation may restore the normal 
 biomechanics of the thoracic spine , decreasing mechanical stress and increasing the 
 distribution of joint forces in the cervical spine28 . secondly , the thoracic manipulation may alter the biomechanics of 
 the thoracic spine , which is related to the cervical spine29 , 30 and may affect the range 
 of motion in the entire spine . results of this study also indicated that immediately after thoracic manipulation , the crom 
 significantly increased in comparison to the control group in terms of flexion , extension , 
 left and right lateral flexion , and left rotation . twenty - four hours after thoracic 
 manipulation , crom significantly increased in comparison to the control group in terms of 
 flexion , left lateral flexion and left rotation . furthermore , results from the current study 
 also revealed significant increases in crom in extension and left rotation immediately after 
 treatment , when comparing the thoracic manipulation and thoracic mobilization groups . this 
 finding may be due to the specific symptoms of the subjects who participated in the 
 manipulation group . nine of thirteen subjects ( 69.23% ) revealed symptoms on their left side . 
 additionally , this may due to the crom of the subjects at baseline in the manipulation group 
 being less than the mobilization group . the crom for the manipulation group in extension and 
 left rotation was 48.51 and 53.33 degrees , respectively , while the mobilization group was 
 58.82 and 57.54 degrees , respectively . this may by a reason why the crom for the 
 manipulation group significantly improved in extension and left rotation when compared to 
 the mobilization group . this study demonstrated no statistically significant differences in pain at rest 
 post - intervention ( vas ratings ) among the control and the treatment groups . however , 
 results do indicate that the level of pain at rest in patients who receive thoracic 
 manipulation decreases more than in patients who do not . as previously mentioned , the 
 studies involved subjects with acute to sub - acute mechanical neck pain ( <3 months)13,14,15 . the present investigation examined 
 patients with chronic neck pain , who had symptoms more than 3 months in duration . moreover , 
 previous studies were performed with manipulation at several levels of the thoracic 
 spine13 . this study was limited to investigation of the immediate and short - term effects of single 
 level thoracic manipulation on patients with chronic mechanical neck pain . future studies 
 should investigate the long - term effects of single level thoracic manipulation on patients 
 with chronic mechanical neck pain . since , the present study only investigated the effects of 
 mobilization / manipulation at the t6-t7 vertebrae on pain at rest and crom , future trials 
 should also investigate the effectiveness of mobilization / manipulation at different levels 
 of the thoracic spine in patients with chronic mechanical neck pain . in summary , the subjects in this study reported reductions in pain at rest and increases in 
 crom in all movements of the cervical spine after single level thoracic manipulation at 
 t6-t7 in patients with chronic mechanical neck pain . single - level thoracic mobilization at 
 t6-t7 for patients with chronic neck pain led to significantly reduced pain levels at rest 
 and increased crom ( in some directions ) by comparison with a control group . additionally , the findings of 
 this study demonstrated increases in crom in extension and left rotation as immediate 
 effects of manipulation versus mobilization treatments . however , this study did not find 
 significant differences between the two techniques in pain level at rest immediately or 24 
 hours after intervention . the potential long - term effects of such interventions need to be 
 further explored .
[ purpose ] to investigate effects of thoracic manipulation versus mobilization on chronic 
 neck pain . 
 [ methods ] thirty - nine chronic neck pain subjects were randomly assigned to 
 single level thoracic manipulation , single level thoracic mobilization , or a control 
 group . 
 the cervical range of motion ( crom ) and pain ratings ( using a visual analog scale : 
 vas ) were measured before , immediately after and at a 24-hour follow - up . 
 [ results ] 
 thoracic manipulation significantly decreased vas pain ratings and increased crom in all 
 directions in immediate and 24-hour follow - ups . 
 the thoracic mobilization group 
 significantly increased in crom in most directions at immediate follow - up and right and 
 left rotational directions at the 24-hour follow - up . 
 comparisons between groups revealed 
 the crom for the manipulation group to increase significantly more than for control 
 subjects in most directions at immediate follow - up and flexion , left lateral flexion and 
 left rotation at the 24-hour follow - up . 
 the crom for the thoracic mobilization group 
 significantly increased in comparison to the control group in flexion at immediate 
 follow - up and in flexion and left rotation at the 24-hour follow - up . 
 [ conclusion ] the 
 study demonstrated reductions in vas pain ratings and increases in crom at immediate and 
 24-hour follow - ups from both single level thoracic spine manipulation and thoracic 
 mobilization in chronic neck pain .