3D kinematic analysis and clinical evaluation of neck movements in patients with whiplash injury

3D kinematic analysis and clinical evaluation of neck movementsin patients with whiplash injury

F Antonaci, M Bulgheroni, S Ghirmai, S Lanfranchi, E Dalla Toffola1, G Sandrini & G Nappi2

Department of Neurological Sciences, University of Pavia, IRCCS ‘C. Mondino Foundation’ and 1Department of Rehabilitation,

IRCCS ‘S. Maugeri Foundation’, Pavia, and 2VI Chair of Neurology and Otorhinolaryngology, University ‘La Sapienza’, Rome and IRCCS ‘C. Mondino

Foundation’, Pavia, Italy

Antonaci F, Bulgheroni M, Ghirmai S, Lanfranchi S, Dalla Toffola E, Sandrini G

& Nappi G. 3D kinematic analysis and clinical evaluation of neck movements in

patients with whiplash injury. Cephalalgia 2002; 22:533–542. London. ISSN 0333-1024

In recent decades whiplash injuries, being a major reason for compensation claims, have

become increasingly important in forensic medicine. In view of this, a reliable diagnostic

method of assessing cervical range of motion (ROM) is needed. The aim of the present

study was to evaluate neck function with a 3D kinematic method compared with clinical

evaluation in whiplash injury. Seventy consecutive patients (M/F=18/52) with a history

of whiplash injury (WH) and 46 healthy volunteers (M/F=24/22), mean age,

respectively 33¡9 and 28¡6 years (mean¡SD) entered the study. Patients suffered

from neck pain and/or unilateral headache. A computerized kinematic analysis of

the ROM (Elite system) using passive markers and two infrared TV cameras was used.

Clinical evaluation of active ROM was also performed both in patients and in 61 controls

(M/F=23/38; mean age 47¡18 years). Thirty out of 70 patients were tested at the time of

their first consultation (T0) and 6 months later (T6), and 12 were also followed up after a

year (T12). All neck movements, except extension, were significantly reduced in WH

subjects compared with controls, in particular lateral bending. Comparing ROM at T0,

T6 and T12, no significant differences were found. A global index of motion

(GIM), obtained by calculating the sum of ROM in absolute value for all the move-

ments acquired, was significantly reduced in WH compared with control subjects. The

interobserver reliability of the clinical evaluation was globally acceptable. On the basis

of the clinical evaluation, a significantly reduced ROM was found in all movements in

WH subjects compared with an age-matched population. Computing the number

of impaired cervical movements (ICMs), a significantly higher number was observed

in WH patients than in controls, showing a decreasing trend at T6 and T12, with a

significant improvement at T6 vs. T0. The computerized study of neck ROM may

constitute a useful tool in the evaluation of WH at baseline and follow-up. uKinematic

analysis, whiplash, neck movement, cervicogenic headache

Fabio Antonaci, Department of Neurological Science, University of Pavia,

‘C. Mondino Foundation’, Via Palestro 3, 27100 Pavia, Italy.

E-mail [email protected] Received 18 December 2001, accepted 24 April 2002

Introduction

In recent decades, many attempts have been made to

obtain an objective method of assessing cervical spine

mobility (1–9). Indeed, because of the complexity of the

cervical joint apparatus, clinical evaluation alone may

not be adequate in all situations. Furthermore, cervical

spine mobility is thought to be influenced by ageing,

biomechanical factors and degenerative processes. Thus,

neck movement analysis is of clear clinical importance

and requires a technique that is neither invasive nor

complex to perform, and that provides reliable para-

meters. While for routine evaluation a rough clinical

assessment based upon pure subjective evaluation may

be sufficient, in case of cervical anaesthetics procedure

or evaluation of certain treatment, a much higher degree

of resolution should be used.

The function of the cervical spine has been kinemat-

ically examined in the past, using sequences of lateral

X-rays, usually of the flexion-extension range of motion

# Blackwell Science Ltd Cephalalgia, 2002, 22, 533–542 533

(ROM) (2–4, 8), and cineradiography (5). However,

given the considerable difficulty involved in obtaining

diagnostically and clinically useful information from

the vast amount of data produced by the computerized

reconstruction and elaboration of neck movements

(2–4, 8), these techniques were progressively discarded.

Thus, several instruments such as goniometers (1, 7,

9–13) and inclinometers/cybex (14–16) have been devel-

oped for the non-invasive evaluation of cervical spine

movement. Although these devices are easy to use, not

expensive and some of them have also shown reliability

(9–13), they have proven to be cumbersome for patients

(11), and to require the intervention of skilled examiners.

Inclinometers, in particular, although easy to use, quick

and inexpensive, have shown a relatively low level of

intraobserver reliability (1, 15).

Recently, different studies (17–20) have been con-

ducted to obtain a 3D kinematic analysis model of

the anatomical head–neck structure by means of opto-

electronic scanners. Such instruments were developed

to quantify ROM and analyse qualitatively other para-

meters like the pattern of curvature, centre of rotation,

etc. Furthermore, 3D kinematic evaluation of cervical

ROM has been shown to be useful in assessing the

coupled joint motion (17) that occurs at different levels

in the cervical spine, in order to identify ‘abnormal’

mobility and thereby to improve the accuracy of motion

analysis.

The method used in the present study allows the

measurement of the active ROM during the execution

of head flexion-extension, lateral bending and axial

rotation movements by means of an ad hoc 3D anatomical

model (21).

Since the pathogenic substrate of neck sprain is

still far from being known, it is a demanding task to

unravel putative and subtle abnormalities using more

sophisticated 3D studies.

The aim of the present work was to evaluate the

usefulness of a 3D kinematic method, compared with

the clinical evaluation, in the study of neck function in

whiplash injury, in order to quantify any impairment

of cervical spine mobility (21) and the outcome of the

disease.

Patients and methods

Patients

Seventy consecutive patients (M/F=18/52), referred to

the ‘C. Mondino Foundation’, with a history of whiplash

injury and 46 healthy volunteers (M/F=24/22), mean

age, respectively 33¡9 and 28¡6 years, entered the

study. Patients included were required to have sustained

a whiplash injury more than 1 month earlier. The illness

duration was j1 year in 42 patients (5¡3 months; j6

months in 26 of these) and >1 year in 28 (49¡30

months). In accordance with the Quebec Task Force

(QTF) Classification of Whiplash Associated Disorders

(WADs) (1995) (22), 56 patients were diagnosed as grade

2 and 14 as grade 3. All of them suffered from neck

pain and/or unilateral headache (if bilateral, the pain

was predominant on the same side).

Thirty-eight subjects had been involved in a rear-end

collision and 6 in a frontal collision; in 14 patients

neck sprain resulted from a lateral impact, while in 12

a mixed mechanism was described.

All patients were tested with the Elite at the time

of their first consultation (T0). Thirty of them were

re-examined 6 months later (T6) and 12 of these 30

patients were also followed-up at 12 months (T12).

A pure clinical evaluation of active ROM was also

performed both in the 70 whiplash injury (WH) patients

(M/F=18/52) and in 61 historical controls (M/F=23/

38; mean age 47¡17.9 years). An age-matched group of

45 subjects (M/F=9/36; mean age 37.5¡11.6 years),

selected from the historical control group, was compared

with the WH patients. The series of controls denied

any head/neck trauma and/or any history of headache

(migraine, episodic tension-type headache (TTH)

>1 day/month) or neck pain.

Methods

Patients were evaluated using a structured interview

and screened by means of a questionnaire applying the

diagnostic criteria for cervicogenic headache (CEH)

(23, 24), migraine without aura (M) (IHS) and headache

associated with neck disorders (HN) (IHS Classification

Committee, 1988) (25). On the basis of IHS diagnostic

criteria, after a 3-month well-documented retrospective

history recording, patients with TTH were excluded. At

the time of the first consultation the litigation was still

open while at 6-months follow-up any claims were

resolved.

Neck movement assessment

In order to assess cervical spine movements, computer-

ized kinematic analysis (Elite system) was performed by

means of passive markers and two infrared TV cameras

working at a sampling rate of 50 Hz. The Elite system

(B|T|S, Milan, Italy), a TV image processing system,

supplies the 3D co-ordinates of all visible markers,

evaluating cervical spine ROM with respect to the trunk

(degrees) (Fig. 1). The kinematic model developed

required the reconstruction of six anatomical points,

three of them describing the head and the other three

describing the trunk. The selected points are shown in

534 F Antonaci et al.

# Blackwell Science Ltd Cephalalgia, 2002, 22, 533–542

Fig. 1. The reliability of this system has been

demonstrated in a previous study (21).

The subject was comfortably seated and looking

straight ahead before performing each recording session,

with shoulders and thorax kept in a fixed position to

guarantee the selective measurement of the cervical

spine movement.

To avoid disturbances on acquired data because of

hair movement, the subjects were wearing special elastic

cotton caps fixing and hiding their hair.

The subjects were asked to perform, in sequence, the

following active movements: head flexion-extension,

lateral bending and axial rotation. Each movement

was repeated five times with no pauses in between.

The sequences had to be performed at natural cadence,

aiming to obtain the maximum ROM. The mean of

three movements (excluding the highest and lowest

ones) was taken as the real ROM value. Further details

on the apparatus and the mathematical reconstruc-

tion of marker co-ordinates have been provided by

Bulgheroni et al. (21). Zero degree was taken as the

neutral position and the ROM was calculated as an

absolute value (21).

In the present study, we also calculated a global

index of motion (GIM), as the sum (in degrees) of the

ROM in absolute value for all the movements acquired.

Moreover, the percent variation, compared with baseline

(T0), of each movement at T6 and T12, respectively, was

also calculated.

Two experienced examiners performed clinical

evaluation, assessing right and left flexion, right and

left extension-rotation, right and left flexion-rotation,

right and left lateral flexion, right and left rotation. ROM

was clinically assessed as follows: 0=100% dysfunction,

1=75% dysfunction, 2=50% dysfunction, 3=25% dys-

function, 4=no dysfunction, where dysfunction stays for

reduced functionality of neck movement. Furthermore,

the number of impaired cervical movements (ICMs) was

also computed as the sum of movements with a score

ranging from 0 to 3, i.e. with a decreased ROM.

Statistical analysis

The data were analysed using the statistical program

SPSS for Windows (version 6.3).

One-way ANOVA was applied to compare the 3D

kinematic analysis of cervical spine movements in

patients with that in controls.

The intraclass correlation coefficient (ICC) was, as

described by Fleiss (26), calculated for each movement

assessed by clinical evaluation. The ICC is the fraction

of variance calculated by the variation between subjects.

Thus, if the variance between tests (or examiners) is

small compared with the variance between subjects,

then the ICC is close to 1. According to Fleiss (26),

ICC values >0.75 generally mean ‘excellent’. Paired

Student’s t-test was applied to assess whether the mean

differences between examiners were significantly differ-

ent from zero. A two-sided P-value of 0.05 was regarded

as significant.

The non-parametric Mann–Whitney u-test was

performed to assess possible differences in the clinical

evaluation of cervical ROM between WH patients

and healthy subjects (n=46), while the non-parametric

Kruskal–Wallis test was applied between groups of

patients with different illness durations.

ANOVA for repeated measures (with Bonferroni’s test)

was applied to compare 3D kinematic, as well as ICM,

data at T0 vs. those at T6 and at T12. The non-parametric

Friedman’s test was used to compare clinical data at

different times of consultation.

Results

On the basis of the relevant criteria, the following

diagnoses were obtained: CEH (Sjaastad et al. 1990)

(n=24) 34.3%; M (IHS) (n=8) 11.4%; HN (IHS) (n=10)

14.3%; CEH+M (n=8) 11.4%; CEH+HN (n=6) 8.6%;

non-classifiable (n=14) 20%. The relation between

headache and whiplash has not been the object of the

present study.

Kinematic analysis

All neck movements, with the exception of extension,

were significantly reduced in WH patients with whip-

lash injury compared with controls (n=46) (P<0.05), in

particular right and left bending (P<0.005) and left

rotation (P<0.005) (Fig. 2). Grouping patients according

to the QTF scoring system, no significant differences in

(a) (b)

A6LS RS

EOP

LH RH

A5 A4

T3

T2T1

A1 A2

A3

C7

Figure 1 (a) Basic marker set-up on head and trunk while thesubject is still. The markers are as follows: (LH) left and (RH)right sides of the head (located 4 cm either side of head vertex);EOP, external occipital protuberance; C7, seventh cervicalvertebra; (LS) left and (RS) right shoulders on the acromionprotuberance. (b) Technical markers (T1–T3) and anatomicalmarkers (A1...A6) during the anatomical calibration procedure.

Neck movements in patients with whiplash injury 535

# Blackwell Science Ltd Cephalalgia, 2002, 22, 533–542

ROM were found when CEH patients were compared

with those with no CEH.

WH patients with a recent whiplash (j1 year) showed

a somewhat reduced ROM (in particular left rotation)

when compared with those with an illness duration >1

year. Furthermore, subjects with a neck sprain within the

previous 6 months showed significantly reduced neck

extension in comparison with patients with a longer

illness duration (>6 months) (P<0.05) (Fig. 3).

The GIM, calculated as the sum of the ROM of all

the movements acquired, was significantly reduced

(P<0.005, ANOVA one-way) in WH patients (252u¡66u)compared with controls (310u¡59u) (Table 1). Further-

more, patients with a recent whiplash injury (j6

months) (233u¡73u) showed a slightly, non-significantly

reduced ROM when compared with those with a

longer disease duration (262u¡60u); the same result

was produced by comparing patients who had sustained

a neck sprain within the previous year (237u¡68u) with

those with a longer whiplash history (273u¡58u).No significant correlation was found between ROM

and WAD score (QTF Classification) (22), and, respec-

tively, headache diagnosis, type of collision and pain

side.

Comparing ROM at 12-month follow-up with T0 and

T6, no significant differences emerged, even though for

some variable cervical spine mobility showed a trend

towards improvement. When comparing T6 vs T0 only

left rotation was significantly improved (Table 2).

The mean percent variation of cervical ROM for each

movement was also calculated (Table 3); at T6 a

relatively small increase (<30%) was noticed but, due

to the large standard deviation, no relevance was

attached to the finding.

When T12 was compared with T0 a large percent

increase (>50%) was recorded in right and left lateral

bending, with a significant improvement emerging

in right lateral bending when comparing T0 with T6

and with T12 data (P<0.05, ANOVA for repeated

Range of motion (degrees)

–60

Mo

vem

ents

LB

E

LR

–40 –20 0 20 40 60

RB

F

RR

Figure 3 Cervical range of motion (ROM) assessed by 3Dkinematic analysis in patients with a recent whiplash (WHj6months) and in those with a longer illness duration (WH>6months). E, Extension; F, flexion; LR, left rotation; RR, rightrotation; LB, left bending; RB, right bending. &, WHj6months (n=26); u, WH>6 months (n=44). *P<0.05,Kruskal–Wallis.

Range of motion (degrees)

–80 –60

Mo

vem

ents

LB

E

LR

–40 –20 0 20 40 60 80

RB

F

RR

Figure 2 Cervical range of motion (ROM) assessed by 3Dkinematic analysis in whiplash patients (WH) and in controls(Co). E, Extension; F, flexion; LR, left rotation; RR, rightrotation; LB, left bending; RB, right bending. One-way ANOVA,WH vs. Co. u, Co (n=46); &, WH (n=70). *P<0.05;**P<0.005.

Table 2 Cervical range of motion (ROM) assessed by 3Dkinematic analysis at the first consultation (T0) and at the6-month follow-up (T6) in whiplash patients (n=30)

Movement T0 T6

Flexion 25.59¡19.69 17.89¡24.72

Extension 31.58¡13.46 29.16¡9.48

Right lateral bending 29.64¡11.32 32.15¡5.67

Left lateral bending 32.27¡10.37 34.78¡9.00

Right rotation 48.18¡16.47 46.07¡14.57

Left rotation 50.72¡16.85 57.54¡12.29*

Values are expressed in degrees.*P<0.05; Student’s paired t-test.

Table 1 Global index of motion (GIM) in whiplash patients atT0, grouped as whiplash (WH) j6 months and >6 months,at T6, at T12 and controls (Co)

GIM

mean¡SD (u)

WH (T0) (n=70) 252¡66*

WHj6 months (T0) (n=26) 233¡73

WH>6 months (T0) (n=44) 262¡60

WH (T0) (n=30) 211+51

WH (T6) (n=30) 228¡46

WH (T12) (n=12) 218¡58

Co (n=46) 310¡59

*P<0.005; ANOVA one-way vs. Co.

536 F Antonaci et al.

# Blackwell Science Ltd Cephalalgia, 2002, 22, 533–542

measures) (Table 3). No major differences were found

when comparing ROM at T12 and at T6.

No significant difference in GIM emerged when data

from the time of the first consultation were compared

with those at the T6 and at the T12 follow-up.

Clinical evaluation

The interobserver reliability of the clinical evaluation,

computed according to Fleiss (26), was good for all

movements (0.68–0.86) with the exception of left lateral

flexion (ICC=0.47) (Table 4).

At clinical evaluation, WH patients showed a

decreased ROM compared with age-matched controls,

as shown in Table 5. Up to 80% of healthy subjects

showed no dysfunction (score 4) in any cervical move-

ment, the only exception being lateral flexion (impaired

in 47% of controls). On the other hand, 63–91% of WH

patients showed a dysfunction ranging from 100% to

25% (score=0–3), lateral flexion being the movement

most frequently reduced (Table 5).

When WH patients were compared with an age-

matched population (Table 5), a significantly reduced

ROM was found in all movements (P<0.05 in right

flexion-rotation and right rotation, P<0.005 in exten-

sion-rotation, flexion, left flexion-rotation, left lateral

flexion and left rotation; Mann–Whitney u-test), in

Table 3 Percent variation of range of motion (ROM) evaluatedwith 3D kinematic analysis in whiplash patients

Movements

Cervical ROM,

% variation

(mean¡SD)

T6 vs. T0 (n=30)

((T6–T0)/T0)

Extension 22.8¡117.5

Flexion 44.1¡204.5

Right bending 25.4¡53.6

Left bending 21.0¡45.9

Right rotation 8.7¡63.9

Left rotation 19.8¡30.7

T12 vs. T0 (n=12)

((T12–T0)/T0)

Extension x20.6¡16.2

Flexion 6.7¡49.5

Right bending 56.2¡63.9

Left bending 67.0¡98.2

Right rotation 31.2¡72.4

Left rotation x12.9¡76.0

T12 vs. T6 (n=12)

((T12–T6)/T6)

Extension 5.5¡51.8

Flexion 9.6¡20.4

Right bending x0.3¡22.9

Left bending 12.8¡33.8

Right rotation x0.7¡18.0

Left rotation x35.1¡68.4

Table 4 Intraclass correlation coefficient (ICC) values forcervical movements assessed by clinical examination tocompare mean differences between the two examiners

Movement ICC

Right flexion 0.68

Left flexion 0.68

Right extension-rotation 0.72

Left extension-rotation 0.72

Right flexion-rotation 0.86

Left flexion-rotation 0.86

Right lateral flexion 0.73

Left lateral flexion 0.47

Right rotation 0.77

Left rotation 0.78

Table 5 Clinical evaluation in whiplash patients (n=70) andin an aged matched population (n=30)

Movement

Whiplash Controls

0–3 4 0–3 4

Right flexion (score)

n 44 22 4 26

% 67 33 13 87

Left flexion

n 44 22 4 26

% 67 33 13 87

Right extension-rotation

n 46 20 6 24

% 70 30 20 80

Left extension-rotation

n 46 20 6 24

% 70 30 20 80

Right flexion-rotation

n 44 26 6 24

% 63 37 20 80

Left flexion-rotation

n 50 20 6 24

% 71 29 20 80

Right lateral flexion

n 62 6 14 16

% 91 9 47 53

Left lateral flexion

n 60 8 14 16

% 88 12 47 53

Right rotation

n 46 24 6 24

% 66 34 20 80

Left rotation

n 50 20 6 24

% 71 29 20 80

For statistical significance see text.

Neck movements in patients with whiplash injury 537

# Blackwell Science Ltd Cephalalgia, 2002, 22, 533–542

particular in right lateral flexion (P<0.001). The sig-

nificance of ROM impairment increased when matching

WH patients vs. controls both with a decreased ROM

(score 0–3) (Table 5).

Computing the number of ICMs, a significantly higher

number was found in WH patients than in controls

(P<0.001) (Table 6a). Since 74% of WH patients showed

more than five reduced movements, and in 87% of

controls four or less movements were reduced, we took

impairment of more than five cervical movements as

a reliable ‘cut-off’ point to distinguish reduced ROM

(>5) from normal ROM (j5) (Fig. 4). Moreover, the

number of ICMs was significantly higher in WH patients

with a recent whiplash injury (j6 months) than in

those with a longer illness duration (Table 6b), and when

comparing T0 vs. T6 and vs. T12 (Fig. 5), a significant

reduction in ICMs was found at T6 vs. T0 (P<0.05,

ANOVA for repeated measures, Bonferroni’s test)

(Table 6c). In Table 7, the frequency and percentage of

clinical dysfunction in patients with a recent whiplash

injury (j6 months) and in WH patients and longer

illness duration (>6 months) are shown.

A higher percentage of recent whiplash injury subjects

(77–100%) than patients with longer disease duration

(50–86%) showed a reduced ROM, the most frequently

reduced movements being extension-rotation, left flex-

ion-rotation and lateral flexion (Table 7). Lateral flexion

was also the most frequently reduced movement in WH

sufferers with a longer disease duration. No significant

differences were found at clinical evaluation of neck

movement when comparing patients at T0, T6 and T12.

Patients with a whiplash occurring between 6 months

and 1 year and those who had sustained a whiplash

injury within the previous 6 months showed a significant

clinical impairment of flexion-rotation and extension-

rotation movements (respectively: P<0.05 and P<0.001,

b. Number of ICMs on clinical evaluation in WH patientswith a recent whiplash (j6 months) and WH patients with alonger illness duration

No. ICM,

mean¡SD

WHj6 months 8.9¡1.8*

WH>6 months 5.9¡3.1

*P<0.005; Mann–Whitney test.

Table 6 Number of impaired cervical movements (ICMs) onclinical evaluation

a. Number of ICMs on clinical evaluation in WH patients andin an age-matched population

No. ICM,

mean¡SD

WH patients 7.0¡3.0*

Controls 2.4¡2.8

*P<0.001; one-way ANOVA.

Number of impaired cervical movements

0

Nu

mb

er o

f p

atie

nts

5

20

1 2 4 6 8 10

10

25

30

15

05 7 9

Figure 5 Number of impaired cervical movements in whiplashpatients (WH) at time of first consultation, at 6-month (T6) and12-month (T12) follow-up. s, WH T0; u, WH T6; n, WH T12.

Number of patients

0

No

. of

imp

aire

d c

ervi

cal m

ove

men

ts

8

1

4

5 10 15 20 25 30

9

2

5

10

3

6

0

7

262

12

12

1222

24 6

8

10 2

Figure 4 Number of impaired cervical movements (ICMs) inwhiplash patients (WH) and in controls (Co). u, Co (n=30);hatched, WH (n=70).

c. Number of ICMs at clinical evaluation in WH patients atT0 (n=70), T6 (n=26) and T12 (n=12)

WH

No. ICM,

mean¡SD

T0 7.0¡3.0

T6 3.0¡4.2*

T12 1.1¡2.8

*P<0.05; ANOVA for repeated measures, Bonferroni test.

538 F Antonaci et al.

# Blackwell Science Ltd Cephalalgia, 2002, 22, 533–542

Kruskal–Wallis test) when compared with subjects with

a longer disease duration.

No significant differences emerged among WH

patients when comparing clinical evaluation at T0 with

T6 and T12 (Friedman’s test), although a trend towards

improvement was seen.

Discussion

Many different opto-electronic devices have been

conceived to obtain non-invasive, three-dimensional

dynamic measurements of neck mobility (17–20).

3D kinematic analysis allows cervical spine function

to be investigated, detecting ROM impairment not only

due to organic lesions, as in the case of simple X-rays,

but also due to neck dysfunction.

Dynamic radiographs, in fact, although useful for

examining kinematic function of the cervical spine,

necessitate a considerably high and lengthy exposure

to radiation, which increases as (in order to obtain a

more detailed examination) the number of X-rays is

increased.

Despite its sophisticated software, the Elite system

is reliable and relatively easy to use (17). Based on a

simplified kinematic model of the anatomical head–neck

structure, it evaluates the head and trunk as two rigid

bodies able to move freely in space, without the need

to restrict the subject’s movement. The direct acquisition

of markers positioned over selected points and/or of

the so-called ‘technical markers’ (see Methods) elim-

inates the errors associated with marker positioning

and detection that occur during X-ray elaboration,

in particular when two radiographic projections

are superimposed, and homologous landmarks have to

be detected in both of them (2). However, even in the

case of 3D kinematic analysis, specific staff training is

necessary and the equipment used is expensive. While it

is true, however, that goniometers and inclinometers (5,

7, 9–13) are inexpensive, quick, easy to use, and can

show an acceptable, and in some cases even good, level

of reproducibility, the intervention of an experienced

examiner is nevertheless needed to increase the accuracy

of the measurement. Inclinometers, in particular, have

been shown to have rather poor resolution (15u), and not

to be good tools for follow-up evaluation over a long

period of time (15).

The first device conceived by Roozmon et al. (19, 20),

the Cervicoscope (a variation of the Spinescope, albeit

improved by the addition of a display to describe

coupled joint motion) (20), requires sophisticated soft-

ware engineering techniques to present the required

information to clinicians efficiently and accurately. In

fact, while the Elite system evaluates the position of the

anatomical segments by measuring the angle between

the head and the laboratory co-ordinate system, the

Cervicoscope software is based on the movement of

vectors calculated from the 3D spatial co-ordinates of

the infrared emitting diodes (IREDs) placed on the head,

neck, and shoulders. This procedure is based on the

development of three algorithms to deduce the relative

direction angles between vectors normal to the different

groups of IREDs and with respect to the absolute

reference frame. Therefore, the method used in the

present study extrapolates biomechanical parameters of

real clinical relevance.

Moreover, the Elite kinematic model, based on the

reconstruction of six anatomical points, is, unlike the one

based on 3D facial morphometry applied by Ferrario

et al. (17), able to supply a complete description of

head/neck mobility. This latter method, in fact, using

Table 7 Clinical evaluation in patients with a recent whiplash(j6 months) (n=26) and in those with a longer illnessduration (>6 months) (n=44)

Movement

Whiplash j6 months Whiplash >6 months

0–3 4 0–3 4

Right flexion (score)

n 20 6 24 16

% 77 23 60 40

Left flexion

n 20 6 24 16

% 77 23 60 40

Right extension-rotation

n 26 0 20 20

% 100 0 50 50

Left extension-rotation

n 26 0 20 20

% 100 0 50 50

Right flexion-rotation

n 22 4 22 22

% 85 15 50 50

Left flexion-rotation

n 26 0 24 20

% 100 0 55 45

Right lateral flexion

n 26 0 36 6

% 100 0 86 14

Left lateral flexion

n 24 4 36 6

% 92 8 86 14

Right rotation

n 20 6 26 18

% 77 23 59 41

Left rotation

n 22 4 28 16

% 85 15 64 36

Neck movements in patients with whiplash injury 539

# Blackwell Science Ltd Cephalalgia, 2002, 22, 533–542

the same digital image analyser, assessed alterations in

the pattern of movement, calculating instantaneous

centre of rotation and radius curvature only for

flexion-extension movement, without considering lateral

bending and rotation.

In contrast, the 3D anatomical model used in the

present study made it possible to compute (in degrees

of motion) the active cervical ROM for each movement

evaluated, without any mechanical constraint, and,

calculating velocity and acceleration of all visible

markers, to obtain a more in-depth investigation.

A more complex 3D kinematic analysis method

was used by Osterbauer et al. (18) in a relatively

recent study, in which instantaneous helical axis (IHA)

and a total biomechanical score were computed to

characterize qualitatively movements of the head

relative to the trunk. This method, based on a complex

mathematical reconstruction of neck movements,

describes alterations in the estimation of IHA during

flexion-extension and oblique tracking tasks.

In our setting, all neck movements, with the exception

of extension, were significantly reduced in whiplash

patients. Osterbauer et al. (18), too, found a significant

impairment of neck mobility in patients with whiplash

injury. In order to find a biomechanical parameter that

describes the total motion of the cervical spine, a GIM

was calculated. This appeared to be useful as a first

approach to neck impairment, as whiplash patients,

compared with controls, showed a significantly reduced

GIM, even though we were unable to detect any

significant differences between patients grouped accord-

ing to the WAD classification, between different types

of headache or between patients at T6 and T12. These

data seemed to agree with those obtained by Osterbauer

et al. (18): the total biomechanical score computed in

their study showed good sensitivity and specificity. It

is worth noting that while we asked patients to perform

three movements at a natural cadence, starting from

their normal sitting position, the patients of Osterbauer

et al. (18) were required to trace lines on the wall with a

laser pointer; in fact, it is more difficult to measure (and

interpret) biomechanical abnormalities occurring in the

path of a set motion than those occurring during free

movements based only on an individual ‘movement

scheme’ (in other words, where there is no requirement

to follow a predetermined trajectory).

Dvorak et al. (4) found hypermobility in the upper

segments in patients with cervical trauma. As often

occurs in whiplash injury, a muscular restraint can result

in a decrease in the muscular force needed to limit

motion at upper and middle cervical spine level where,

because of the less stable gliding motion of the cervical

spine at these levels, considerable muscular force is

required. In the present study, in contrast, whiplash

patients showed normal ROM as regards extension,

while all the other movements were reduced as in

hypomobility of the lower cervical spine, probably due

to soft tissue damage and/or muscle restraint. Extension

proved to be significantly impaired in patients with

a recent whiplash injury (j6 months), improving in a

shorter time than other neck movements.

Although clinical evaluation showed a globally

acceptable level of interobserver reliability, only

flexion-rotation and rotation movements gave good

ICC values, while left lateral flexion was shown to be

unreliable, probably due to an extreme intra- and

interindividual variability in its amplitude or, possibly,

to weakness towards the end of the examination, when

lateral flexion was usually evaluated. Moreover, it has

to be said that the amplitude of lateral flexion varies

greatly from subject to subject and, without producing

great discomfort, is reduced by age and by degenerative

pathologies, such as arthrosis. Similarly, in a previous

study by Fjellner et al. (27), six of the eight cervical

movements clinically investigated by two experienced

physiotherapists, in particular rotation, showed an

acceptable level of reliability.

The 3D kinematic analysis, in contrast, showed a

good–excellent reproducibility for all movements (21)

and proved to be an objective method that is more

reliable and sensitive than clinical examination. Never-

theless, clinical evaluation proved to be useful, as a basal

screening, in distinguishing whiplash patients from

asymptomatic controls.

Computing the number of ICMs, in order to select

a ‘clinical’ biomechanical parameter that describes

the total amount of neck motion, we noticed that 74%

of patients showed impairment of more than five

movements; whereas four or fewer movements were

found to be reduced in 87% of controls. Thus, we took

impairment of more than five cervical movements as

a ‘cut-off’ point to distinguish neck dysfunction (with

a reduced ROM) from normal cervical spine mobility.

This ‘cut-off’ point, and the ICMs themselves, were

shown to constitute a good and useful ‘marker’ of neck

impairment, as revealed by the significant differences

both between WH patients and controls and between

patients with a recent whiplash injury and those with a

longer respite since the whiplash. Furthermore, the

ICMs, showing a trend towards decrease (i.e. towards

improved ROM), also proved to be quite useful not

only in the diagnosis, but also in the follow-up of

cervical spine dysfunctions (in particular whiplash

injury). In our setting extension-rotation, left flexion-

rotation and lateral flexion were the movements

most frequently impaired in patients with a recent

whiplash injury (and lateral flexion the most frequently

reduced also in those with a longer disease duration).

540 F Antonaci et al.

# Blackwell Science Ltd Cephalalgia, 2002, 22, 533–542

Moreover, flexion-rotation and extension-rotation

were significantly reduced in patients with a recent

whiplash injury (j1 year and j6 months), these two

movements apparently being the most reliable and

useful ‘clinical markers’, at ‘first screening’, for the

diagnosis and follow-up of neck dysfunction. It should

also be noted that lateral movements, such as flexion-

rotation and rotation, showed good reproducibility

(ICC values).

The results of clinical evaluation seem to show a

marked agreement with those of 3D kinematic analysis,

and clinical evaluation seems to be reliable as a first

examination tool, identifying cases of neck dysfunction

that have a high probability of being confirmed by an

objective evaluation such as the 3D kinematic analysis.

These results partially agree with those obtained in the

study by Fjellner et al. (27), indicating a difference in

reliability between symptomatic and asymptomatic

subjects (greater in the former).

Moreover, as regards percent variation, whiplash

patients showed a tendency towards an improvement

in cervical ROM impairment over time. Thus, 3D

kinematic analysis proved to be a useful tool for

follow-up evaluations in neck disorders. The large SD

recorded in flexion-extension movements when com-

paring T6 and T12 with T0 data are due to some patients

showing, at T0, a strongly reduced ROM, which is

increased two to three-fold at T6 and/or T12 follow-up.

The relative high drop-out rate in our patient series may

be due to the fact that cases with a clinical improvement

and solved compensation claim may be less prone to

undergo a new assessment of neck function. Further

follow-up studies may reveal a higher sensitivity by

analysing 3D methods with passive and active clinical

evaluation.

In conclusion, the method for the 3D kinematic

analysis of cervical movements used in this study

proved to be reliable, easily applicable in difficult

clinical cases and, most of all, useful in whiplash

injury diagnosis and follow-up evaluation. Clinical

evaluation, on the other hand, was shown to be useful

as a ‘first screening’ tool correlating with data obtained

using the 3D kinematic analysis method. However, the

Elite system remains a ‘sophisticated’ method of

spine movement evaluation, and due to its cost is not

designed for routine use but mainly for difficult clinical

cases in forensic medicine and for research purpose.

Acknowledgements

This study was supported by a grant from the Ministry of PublicHealth no. 57.2/RF93.28. The authors are indebted to ProfessorOttar Sjaastad for fruitful criticism. Appreciation is expressed toMiss Paola Castellotti for laboratory assistance.

References

1 Alaranta H, Hurri H, Heliovaara M, Soukka A, Harju R.

Flexibility of the spine: normative values of goniometric

and tape measurements. Scand J Rehab Med 1994;

26:147–54.

2 Amevo B, Aprill C, Bogduk N. Abnormal instantaneous

axes of rotation in patients with neck pain. Spine 1992;

17:748–56.

3 Dimnet J, Pasquet A, Krag MH, Panjabi MM. Cervical spine

motion in the sagittal plane: kinematic and goniometric

parameters. J Biomechanics 1982; 15:959–69.

4 Dvorak J, Panjabi MM, Grob D, Novotny JE, Antinnes JA.

Clinical validation of functional flexion/extension radiograph

of the cervical spine. Spine 1993; 18:120–7.

5 Fielding JW. Dynamic anatomy and cineradiography of the

cervical spine. In: Bailey RW, editor. The cervical spine.

Philadelphia: Lea & Febiger, 1974.

6 Hanten WP, Lucio RM, Russel JL, Brunt D. Assessment of total

head excursion and resting head posture. Arch Phys Med

Rehabil 1991; 72:877–80.

7 Kadir N, Grayson MF, Goldberg AAJ, Swain MC. A new

goniometer. Rheumatol Rehabil 1981; 20:219–26.

8 Kraemer M, Patris A. Radio-functional analysis of the

cervical spine using the Arlen method. J Neuroradiol 1989;

16:48–64.

9 Podolsky S, Baraff LJ, Simon RR, Hoffman JR, Larmon B,

Ablon W. Efficacy of cervical spine immobilization methods.

J Trauma 1983; 23:461–5.

10 Alund M, Larsson SE. Three-dimensional analysis of the neck

motion: a clinical method. Spine 1990; 15:87–91.

11 Eklund J, Odenrick P, Zettergren S, Johansson H. Head

posture measurements among work vehicle drivers and

implications for work and workplace design. Ergonomics

1994; 37:623–39.

12 Hagen KB, Harms-Ringdahl K, Enger NO, Hedenstad R,

Morten H. Relationship between subjective neck disorders

and cervical spine mobility and motion-related pain in male

machine operators. Spine 1997; 22:1501–7.

13 Tucci SM, Hicks JE, Gross EG, Campbell W, Danoff J. Cervical

motion assessment: a new, simple and accurate method. Arch

Phys Med Rehabil 1986; 67:225–30.

14 Highland TR, Dreisinger TE, Vie LL, Russel GS. Changes in

isometric strength and range of motion of the isolated cervical

spine after eight weeks of clinical rehabilitation. Spine 1992; 17

(Suppl.):77–82.

15 Moffet JAK, Hughes I, Griffiths P. Measurement of cervical

spine movements using a simple inclinometer. Physiotherapy

1989; 75:309–12.

16 Zwart J-A. Neck mobility in different headache disorders.

Headache 1997; 37:6–11.

17 Ferrario F, Sforza C, Poggio CE, Schmitz JH, Tartaglia G.

A three-dimensional non-invasive study of head flexion

and extension in young non-patient subjects. J Oral Rehabil

1997; 24:361–8.

18 Osterbauer PJ, Long K, Ribando TA, Peterman EA, Fuhr AW,

Bigos SJ et al. Three-dimensional head kinematics and cervical

range of motion in the diagnosis of patients with neck trauma.

J Man Physiol Ther 1996; 10 (4):231–7.

19 Roozmon P, Gracovetsky SA, Gouw GJ, Newman N.

Examining motion in the cervical spine I: imaging

Neck movements in patients with whiplash injury 541

# Blackwell Science Ltd Cephalalgia, 2002, 22, 533–542

system and measurement techniques. J Biomed Eng 1993;

15:5–12.

20 Roozmon P, Gracovetsky SA, Gouw GJ, Newman N.

Examining motion in the cervical spine II: characterization

of coupled joint motion using an optoelectronic device to track

skin markers. J Biomed Eng 1993; 15:13–22.

21 Bulgheroni MV, Antonaci F, Sandrini G, Ghirmai S,

Nappi G, Pedotti A. A 3D kinematic method to evaluate

cervical spine voluntary movements in humans. Funct

Neurol 1998; 3:239–45.

22 Spitzer WO, Skovron ML, Salmi LR, Cassidy JD, Duranceau J,

Suissa A, Zeiss E. Scientific Monograph of the Quebec

Task Force on Whiplash-Associated Disorders: redefining

‘whiplash’ its management. Spine 1995; 20 (85):10–69.

23 Sjaastad O, Fredriksen TA, Pfaffenrath V. Cervicogenic

headache: diagnostic criteria. Headache 1990; 30:725–6.

24 International Association for the Study of Pain Subcommittee

on Taxonomy. Classification of chronic pain. Pain 1986;

3:1–225.

25 Headache Classification Committee of the International

Headache society. Classification and diagnostic criteria for

headache disorders, cranial neuralgias and facial pain.

Cephalalgia 1988; 8/7:1–96.

26 Fleiss JL. The design and analysis of clinical experiments,

Vol. 1. New York: John Wiley and Sons Inc., 1986.

27 Fjellner A, Bexander C, Faleij R, Strender L-E. Interexaminer

reliability in physical examination of the cervical spine. J Man

Physiol Ther 1999; 22:511–6.

542 F Antonaci et al.

# Blackwell Science Ltd Cephalalgia, 2002, 22, 533–542