Double-blind randomized controlled study of coblationtonsillotomy versus coblation tonsillectomy onpost-operative pain

19 July 2005

Sir,

We read with interest the article by Arya et al.1 ‘Double-

blind randomized controlled study of coblation tonsilloto-

my versus coblation tonsillectomy on post-operative pain’.

This study compared post-operative pain scores from

18 children, in the first 24 h after these procedures were

performed by a single consultant surgeon.

We think the design of this study raises a number of

interesting issues. It is not clear whether there was true

randomization of patients into groups for which side

tonsillotomy was performed. Sealed envelope allocation

and random number allocation are both listed. A sealed

envelope system would not give an equal chance of

allocation to each side as the previous envelopes that had

been picked would influence the probability of being allo-

cated in the remaining envelopes. Allocation according

to a random number generator, however, would have

constituted true randomization. We would also debate

whether the pain assessment used was a true visual

analogue score as responses were scored ‘0, no pain; 1,

hurts when talks, moves or eats; 2, hurts all the time but

not severe; 3, constant severe pain’.1

We were unsure with the authors’ analysis of the data

from the pain scores used in this paper. These scores

were ranked, i.e. non-parametric data. Area under the

curve is only appropriate for parametric data as it relies

on every unit or square under the curve having exactly

the same value. This is not a summary measure that can

be calculated on non-parametric data. Likewise the t-test

is a test of parametric data comparing one data point in

two groups (unpaired) or two data points in one group

(paired).

This study was an original study and looked at a rele-

vant question in the practise of otolaryngology regarding

improving how we can perform tonsillectomies in

children. Post-operative pain is a difficult area to assess

and it could be misleading to draw recommendations for

future practise from data that has not been demonstrated

to be wholly accurate or reliable.J. Davies & A.P. Coatesworth

Department of ENT, York Hospital, Wigginton Rd, YO31 8JT

York, UK

E-mail: johnfdavies@hotmail.com

Reference

1 Arya A.K., Donne A. & Nigam A. (2005) Double-blind rando-

mized controlled study of coblation tonsillotomy versus coblation

tonsillectomy on postoperative pain in children. Clin. Otolaryngol.

30, 226–229

Response to Moorthy & Scott and Davies & Coatesworth

8 August 2005

Sir,

We welcome the feedback comments on our paper.

In response to points raised about data collection with

children, we agree that this is indeed a very difficult area

for research. To this end, we used specific terms to

describe pain levels (e.g. pain when eating) to enable

children to understand, and so in a 5 or 10 point scale

this understanding would have been lost. Moreover, we

performed qualitative analysis to quantify the pain results

obtained, and as we alluded to in the discussion felt

telephone scores would not have maintained the study’s

accuracy.

We consulted a statistician before, during and after the

study and area under the curve (AUC) was decided to be

the best method for analysis. When performing a power

analysis, however, using AUC would have been inaccurate

(especially bearing in mind that power calculation cannot

be performed retrospectively) and would not have signifi-

cantly changed any of the results of the power calcula-

tion. We believe AUC can be used for discrete data, and

so do not regard our results to be inaccurate.

Tonsillotomy as we performed was a complete removal

of tonsillar tissue, with a comparable amount of tissue

remaining to tonsillectomy. There were no occasions

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where excessive tissue remained after surgery, therefore,

no patient was put at extra risk of recurrence.

For full details as to whether coblation is suitable for

tonsillectomy, we would refer readers to the National

Prospective Tonsillectomy Audit results.1 It was never an

objective, in this study, to determine this, and our advo-

cation for coblation tonsillectomy is a personal statement

made from our unit’s experience.

We used random numbers to determine side of opera-

tion and believe correct randomization occurred. It is

recommended to use coblation on the lowest possible set-

ting, and from our experience a setting of 8 for tonsillot-

omy and 6 for tonsillectomy resulted in minimal tissue

damage whilst maintaining adequate effect of the instru-

ment. The analgesia given to patients was not recorded,

but as patients acted as their own control, this was not

thought to be relevant to the study.Arvind Singh

Royal Marsdon, Fulham Road, London, UK,

E-mail: singha@doctors.org.uk

Reference

1 Recommendations on the National Prospective Tonsillectomy

Audit. Available at: http://www.tonsil-audit.org.uk, accessed on 19

July 2005.

The use of camera mobile phone to assess emergency ENTradiological investigations

14 June 2005

Sir,

We read with interest the article on use of camera phone

for transferring ENT radiological images by Eze et al.1

There are major concerns regarding confidentiality, data

protection and patient consent for this practice.

A number of similar studies have been published from

Japan and Taiwan,2–5 countries with less strict data

protection laws. Working in the UK we are under an

obligation to abide by the Data Protection Act 1998

(http://www.dataprotection.gov.uk). There are serious

data protection issues involved with transferring patient

data by mobile phones. Anyone who has a mobile phone

must have experienced receiving and sending a text

message to the wrong person in error, which just involves

a wrong click of the button. By the time the sender real-

ises the mistake it is too late. The possibility of transfer-

ring a patient image to the wrong person is a reality.

According to Confidentiality and Data Protection Guide-

lines at our hospital, personal data relating to patients

should be emailed only via NHSNet using NHS approved

encryption technology (http://www.ich.ucl.ac.uk). Trans-

ferring patient images by personal mobile phones would

certainly not meet the approval of data protection

officers.

Secondly, the issue of patient consent also needs to be

addressed. Any patient images including X-ray images to

be used for teaching, presentation or publication need the

patient’s consent. The moment an X-ray image is clicked

and stored on a personal mobile phone it is out of the

realms of secure hospital systems. We feel that any

patient data stored on personal mobile phones should

not be done without the patient’s consent.

We feel these issues need to be considered before using

the study results in clinical practice.

Conflict of interest

None declared.

Y. Bajaj, D. Crampsey & B. HartleyDepartment of Paediatric Otolaryngology,

Great Ormond Street Hospital, London, UK

E-mail: ybajaj@hotmail.co.uk

References

1 Eze N., Lo S., Bray D., et al. (2005) The use of camera mobile

phone to assess emergency ENT radiological investigations. Clin.

Otolaryngol. 30, 230

2 Hseih C.H., Tsai H.H., Yin J.W., et al. (2004) Teleconsultation

with the mobile camera-phone in digital soft-tissue injury: a feasi-

bility study. Plast. Reconstr. Surg. 114, 1776

3 Kondo Y. (2002) Medical image transfer for emergency care util-

izing internet and mobile phone. Nippon Hoshasen Gijutsu Gakkai

Zasshi 58, 1393

4 Tsai H.H., Pong P.P., Liang C.C., et al. (2004) Teleconsultation

by using the mobile camera phone for remote management of

the extremity wound: a pilot study. Ann. Plast. Surg. 53, 584

5 Yamada M., Watarai H., Andou T., et al. (2003) Emergency

image transfer system through a mobile telephone in Japan: tech-

nical note. Neurosurgery 52, 986

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