A New Study Validates Motion Palpation - or does it
by Dr John Reggars and Dr Simon French

The research to date that has been conducted on the reliability of motion palpation has shown, at best, fair to moderate intra-rater reliability and poor to fair inter-rater reliability.¹ That is, for one examiner palpating the same subject he/she was moderately successful in identifying the same spinal fixation or subluxation over a number of separate examinations, while if several examiners were used the chances were they could not agree on the same level of fixation. The authors of a recent study published in the BMC Musculoskeletal Disorders claim that their research, involving motion palpation of subjects with congenital blocked vertebrae (CBV), validates motion palpation for spinal fixations or manipulable lesions.²

Unfortunately there are some serious short comings with respect to this research. The following article will briefly outline the research together with a critical review of the published paper. (Our comments are in italics).

Humphries et al recruited three asymptomatic subjects with a single level congenital blocked vertebrae. Two of these subjects had CBV at C2/3 and one had CBV at C5/6. The spinous processes were then palpated from C2 to C7 and the skin over the adjacent facet joints was marked bilaterally.

Up to 50% cases of CBV that have fusion of the apophyseal joints often have a single fused spinous process³. This appears to be the case with at least one of the subjects in the current study, as illustrated in a radiograph of one of the subjects recruited for this study. So how did researchers identify the fused joint between C2/3 from one spinous process and therefore what was the actual level being marked, palpated and recorded? The authors also rightly state, in the Limitations section of the paper, that by using only three subjects it may affect the generalisability of their results. Also, the use of asymptomatic subjects maybe clinically irrelevant. Using asymptomatic subjects has been a criticism of reliability studies on motion palpation in the past.

The investigators recruited twenty 4^th year chiropractic students, who had undergone three years motion palpation training, to examine the three subjects. The examiners were blinded to the presence of the CBV and instructed to perform motion palpation as taught in the undergraduate programme and to report the ‘most fixed’ motion segment.

As the authors rightly point out, because each subject underwent twenty separate examinations the subjects are likely to experience some discomfort, which in turn could lead to restricted joint motion. Conversely, repetitive motion testing could have also lead to increased intersegmental motion. Both scenarios could confound the results of this study. The fact that student chiropractors were used in this study may also affect the study outcome, as it has been shown that students were more reliable at detecting spinal fixations using motion palpation than experienced practitioners.^4,5 It would have been interesting if the investigators also utilized experienced practitioners as examiners in their study. The authors conclude that “even novice clinicians demonstrated the ability to correctly identify the presence or absence of known cervical spine intersegmental fixations”, implying that more experienced clinicians would be better at this skill. This is not supported by available evidence.

The results of the study showed that at the C2/3 CBV there was substantial agreement by the students with a Kappa score of K=0.756 but for the C5/6 CBV the Kappa value was K=0.460 (or moderate agreement). However, it is interesting to note that for the subject with C5/6 CBV many examiners identified an upper cervical segment as being the most restricted in motion. The sensitivity for detection of the C5/6 CBV was 55% and for the argument that at the C5/6 CBV level the examiners could only detect the CBV approximately half the time and at the C2/3 level 80% of the time.

Given that at the CBV levels absolutely no movement occurs, one would think that if motion palpation was truly reliable better sensitivity scores would have been achieved. Extrapolating these results to the hypothetical reduced motion in a subluxation/manipulable lesion is obviously problematic. Another conclusion that may be reached from this research, is that if examiners can’t agree completely when no movement at all takes place in a motion segment, how are they going to agree when only a reduction of motion occurs in the case of a vertebral subluxation?

Furthermore, as many examiners missed the C5/6 CBV and selected an upper cervical segment as being the most restricted, sensitivity scores for the C2/3 level could be inflated due to more examiners erroneously identifying that level and therefore confounding the pooled data. The authors account for the examiners wrongly identifying an upper segment, as opposed to the true C5/6 CBV, by stating “It is possible that a true vertebral “dysfunction” was present at the higher segment, causing a number of examiners to implicate it as their most hypomobile finding”. It could also be the case that motion palpation is simply unreliable when applied to the lower cervical spine.

The authors state “Not only is no motion allowed at the level of the CBV, but as previously described, the anomaly can result in increased motion and potential instability at the adjacent motion segments. The relative “fixation” feel at CBV would therefore be enhanced and its detection further facilitated”.

If this were the case why could the examiners only detect the CBV at C5/6 level only 55% of the time? The authors defend this poor agreement with the argument that at the C5/6 spinal level the greatest ranges of motion are in flexion and extension but in the study only rotation and lateral flexion were tested. Further, they opine that there is more overlying soft tissue at this level, which may also account for the poor sensitivity result. Again, could the poor sensitivity in detecting CBV in the lower cervical spine, via motion palpation, simply be due to the method being unreliable?

The authors conclude, “This study indicates that relatively inexperienced examiners are capable of correctly identifying inter-segmental fixations (CBV) in the cervical spine using 2 commonly employed motion palpation tests. The use of a “gold standard” (CBV) in this study and the substantial agreement achieved lends support to the validity of motion palpation in detecting major spinal fixations in the cervical spine”.

We do not believe that the data presented permits the blanket statement that “inexperienced examiners are capable of correctly identifying inter-segmental fixations”.

Finally, the statement “lends support to the validity of motion palpation in detecting major spinal fixations in the cervical spine” infers that motion palpation is a valid method for detecting the manipulable lesion or subluxation. This is drawing a long bow from the results of this study. CBV and spinal fixations or subluxations are two distinct entities. Haldeman⁶ has defined the characteristics of the chiropractic vertebral subluxation to include vertebral malposition, abnormal vertebral motion, abnormal joint play or end feel, soft tissue abnormalities, muscle contraction or imbalance and a response to manipulative treatment. Although CBV would certainly display abnormal motion, or rather a lack of motion and abnormal end feel, the other characteristics of the chiropractic subluxation are absent. Further, from clinical experience, palpation of non-fused segments is most unlikely to result in a finding of a total absence of joint motion and end feel. Therefore, to compare these two entities in the context of motion palpation is absurd.

In general, this study is well designed and innovative, however the authors fail to substantiate many of their assertions and conclusions. This study was reviewed by a world renowned chiropractic researcher and accepted for publication without any major changes. In our view it should not have been published without substantial changes, in particular the conclusion. The implications of this research being accepted into the scientific literature without challenge are significant. Without challenge those practitioners who utilise motion palpation will use this study as validation of their examination method. This study does not validate motion palpation but rather forms a foundation for future research in this area.

1. Seffinger M, et al. Spinal palpatory diagnostic procedures utilized by practitioners of spinal manipulation: annotated bibliography of content validity and reliability studies. J. Can Chiropr Assoc 2003; 47:93-109.
2. Humphreys BK, Delahaye M, Peterson CK. An investigation into the validity of cervical spine motion palpation using subjects with congenital block vertebrae as a “gold standard”. BMC Musculoskeletal Disorders 2004; 5:19. http://www.biomedcentral.com/1471-2474/5/19.
3. Yochum TR, Rowe LJ. Essentials of skeletal radiology Vol 1. Williams & Wilkins: Balitimore MD 1987; 105.
4. Harvey D, Byfield D. Preliminary studies with mechanical model for evaluation of spinal motion palpation. Clinical Biomech 1991; 6:79-82.
5. Jensen K, Gemmell H, Thiel H. Motion palpation accuracy using a mechanical spinal model. Europ J Chiro 1993; 41:67-73.
6. Haldeman S. Spianl manipulation therapy: A status report. In: Clinical Orthopaedics and Related Research. JP Lippincot:t Philadelphia 1983; 116-24.