Questionnaire development
We developed an initial set of questionnaire items in consultation with Murdoch staff
members who taught cervical manipulation technique. An expert panel was then formed,
who used a Content Validity Index (CVI) to ensure that the questionnaire was relevant
to assess neck manipulation competency among chiropractic students 16], 17]. The expert panel consisted of seven chiropractors who teach neck manipulation at
several Australian universities and one international university. The composition
and size of this expert panel was congruent with guidelines that propose that the
panel members’ professional backgrounds reflect that of the target population, and
that the ideal number is between six to twelve members 16], 17]. Every panel member evaluated each item using four categories: not relevant, unable
to assess relevance without major revision, relevant but needs minor alteration, and
very relevant. A value of one was assigned to the “very relevant†and “relevant but
needs minor alteration†categories, whereas a value of zero was assigned to the other
categories. The I-CVI for each item was derived by summing the values for each rater
and then dividing by the number of raters. Items were retained if the CVI exceeded
0.79 16], 17]. After the initial expert panel evaluation and feedback, the pilot version of the
questionnaire was expanded considerably in the domains of rating expertise. In the
second round of evaluation, the I-CVI for individual items ranged from 0.86-1.0 and
all items were retained. The S-CVI, which is the proportion of items rated as either
“relevant but needs minor alteration†or “very relevant†by all raters, was 0.94.
The final questionnaire comprised five assessment criteria, of which three contained
several sub-criteria. The five assessment criteria were:
1) Patient and practitioner positioning
Is the patient positioned correctly?
Is the headrest in the correct position?
Is the practitioner positioned correctly?
2) Joint pre-tension
Has the joint been placed into the pre-manipulative tension position correctly?
3) Contact points
Is the contact point on the patient correct?
Has the correct side of the patient been contacted?
Is the contact on the practitioner’s hand correct?
Is the practitioner’s indifferent/stabilising hand correctly positioned?
4) Vector of correction/line of drive
Is the vector of correction correctly aligned with the presentation of the facet
joints at the level manipulated?
5) Procedure
Is the amplitude of the thrust applied sufficient to address the fixation?
Is the speed of the thrust applied sufficient to address the fixation?
Was the demonstrated manipulation/adjustment executed safely?
Sample
All students enrolled in the fourth of the five year chiropractic program at Murdoch
University during 2014 (N?=?41) were invited to participate. Paper copy information
notices were distributed in the first lecture of 2014, and a non-teaching staff member
delivered an information session and provided an opportunity for students to raise
questions about the study to inform the consent process. Students were informed that
participation was entirely voluntary, and electing to participate or not participate,
would not affect their relationship with University staff in any way. The Murdoch
University Human Research Ethics Committee approval number was 2013/200. All 41 students
initially invited to participate provided consent to have their results included in
the final analysis.
Randomisation and blinding procedure
A staff member, not involved with group allocation, used a random number generator
to generate a randomisation list. The group assignment was placed in sequentially
numbered, opaque, sealed envelopes. After obtaining informed consent, staff not assessing
neck manipulation competency opened the envelope and allocated students to one of
two groups: usual learning or modellearning. Staff assessing neck manipulation
competency, and undertaking data entry and analysis were blinded to group allocation.
Due to the nature of the study it was not possible to blind students to their group
allocation, however at all times the assessor remained unaware of the group randomisation.
Students are aware that under Australian Law, unless they are a registered practitioner
with the Australian Health Professions Regulatory Authority, performing cervical spine
manipulation outside of a recognised training program is prohibited 18]. Thus it is unlikely that students practised cervical spine manipulation outside
of their usual teaching times.
The mannequin
The cervical modelis known as “Flexi-man†and is shown in Figs. 1 2. Fleximan has been developed and manufactured by Dr. Timothy Young, Chiropractor
19]. The modelconsists of a flexible imitation of shoulders, neck and head made
of a pliant “rubberised†material. The weight of the modelis 4.8 kgs with the
specific head weight unknown, however a proxy head weight was 3.2 kgs. This proxy
weight was established by laying the modelprone with the head recumbent on weight
scales. The modelwas designed to allow students to set up, place contacts and
deliver a thrust in a line of drive of their choosing. It does not however allow for
pre-manipulative tension. The modelis a stylised human facsimile and is not designed
to mimic a human specimen. It does not have the variability of human subjects receiving
manipulation, for example height, weight, and tissue compliance. The makers state
that the modelis best used in the introductory phases of training 20].
Fig. 1. The mannequin
Fig. 2. Technique demonstration on the mannequin
Educational interventions
The usual learning group practised neck manipulation techniques on each other under
supervision consistent with the description provided in the introduction to this article.
This learning approach has been used since the inception of the Murdoch University
chiropractic program in 2002. The modellearning group practiced the neck manipulation
techniques on a modelwith a flexible neck, once again under supervision. The
modellearning approach was a novel method not previously used at Murdoch University.
Each group received three, two hour weekly training sessions in the performance of
a commonly used cervical spine manipulation technique referred to as the index pillar
push 21]. During the weekly training sessions and to ensure that the assessor remained blinded
to group allocation students were supervised by academics not involved in the assessment
of the students. The supervising academics provided each student with regular personalised
feedback relating to their performance of the required technique during the weekly
training sessions. After the third weekly training session, all members of each group
crossed over and undertook three additional training sessions using the alternate
method. The flow of the study is displayed in Fig. 3.
Fig. 3. Flow chart of study
All fourth year students who participated in the study had already received training
in neck manipulation in the third year of the program but there is a long summer break
between third and fourth year so skills usually diminish. On the first week back at
University, a staff member experienced in manipulation assessment who was blinded
to group randomisation, assessed the student’s performance of the index pillar push
procedure at baseline on the model(immediately before the first training session)
and then again at four weeks, and eight weeks, by using the validated instrument of
measurement.
Assessing student performance of the index pillar push technique involved the assessor
requesting the student to perform the technique on both the left and the right hand
side of the mannequin. Each student was allowed to perform the technique once on both
sides, while the assessor graded their performance.
The maximum total score on the validated questionnaire is 100 %. In order to pass
the assessment a student must achieve a minimum score of 69 % overall.
Each of the five identified assessment criteria are considered critical to the successful
performance of the required technique. If a student fails to perform one of these
five assessment criteria adequately the student is awarded an overall score of 69
%. Should the student fail to perform two of the five assessment criteria adequately
they are awarded a score of 49 %. Less than satisfactory performance of three criteria
results in a score of 29 %. Inadequate performance of four assessment criteria results
in a score of 19 % being awarded to the student. If all five assessment criteria are
unsatisfactorily performed or the student is unable to perform the required technique,
the student is awarded a score of zero.
Statistical analysis
All data were entered manually into SPSS v.21, cleaned and checked for implausibilities.
A chi-square test was used to examine differences between groups for the proportion
of students achieving an overall pass mark at baseline, four weeks, and eight weeks.