Reviewer's report
Title:Gastronet survey on the use of one- or two-person technique for
colonoscopy insertion
Version: 1Date:28 March 2011
Reviewer: Chyke A Doubeni
Reviewer's report:
Summary:
This is a well-written brief report comparing two colonoscopy techniques: one- vs.
two-person insertion of the colonoscope. In the latter technique, the
colonoscopist directs an assistant to insert the colonoscope while presumably
freeing the colonoscopist to focus on directing the insertion and inspecting the
lumen. As noted by Hoff and colleagues, and in my discussions with some
clinical experts, the 2-person technique is less frequently practiced in the age of
the flexible colonoscope.
The study found that the two-person technique is practiced by 13 (17%) in 6
centers, with both techniques practiced at 5 of those 6 centers. Colonoscopist
using the one-person technique had a higher volume than two-person
Only univariate analyses were performed making it difficult to decipher whether
the reported differences are the result of some unmeasured characteristic or the
practice setting or patient characteristics. Compared to the one-person
technique, cecal intubation better, polyp detection rate lower and intubation time
shorter and use of sedation lower for patients undergoing colonoscopy by
2-person technique.
However, the distinction between one- and two-person techniques may be
difficult to discern in some procedures because circumstances may necessitate
the need for assistance in inserting or advancing the colonoscope even in the
one-person technique.
Therefore, the study appears to have compared the outcomes for colonoscopists
who predominantly perform a one-person to those who performed a two-person
technique. Because some of the colonoscopists switched between techniques,
and the actual technique used for each patient respondent were not determined,
it is difficult to conclude that the results represent the actual merits of the two
techniques. It is possible that the types of patients in the 2-arms are different.
Without additional data, it is difficult to conclude that the variation in polyp
detection rate is not due to some extraneous factor.
1. Major Compulsory Revisions
a. There may be a selection bias, when one looks at respondents compared to
non-respondents. The authors may have missed the opportunity to survey not
just colonoscopists, but also their principal assistants, which would have provided
data on those with missing survey data. It seems feasible to call the centers that
did not respond to get additional data on the most commonly used technique.
b. Another question that is not answered by the study is the costs/resources for
the two techniques. Is the 2-person technique using more resources for fewer
colonoscopies? Does the two-person technique use more staff? Or are the staff
just being used in a different way?
c. A central issue in the paper is the “so what” question. The authors’ explanation
for the findings suggests that there may be merits of both techniques. What this
suggests to me is the need for a qualitative study to provide context on the
differences in the quality outcomes.
d. It is quite possible, and even likely, that the variations may result from factors
other than technique. The authors should provide additional information on what
those factors could be.
e. The discussion section is highly speculative. It should be shortened particularly
the first paragraph.
f. The authors suggest that 2-persontechnique is a “more team-building concept.”
There were no data provided to support that statement and will recommend
removing or modifying that statement.
g. The limitations section ought to acknowledge that the study was not able to
determine which of the two techniques was used for each individual patient but
applied a characteristic of the colonoscopist to each patient treated by him/her.
2. Minor Essential Revisions
a. The title does not seem to reflect what was studied. Does this mean that with
either technique an assistant was not used during withdrawal?
b. Table 2 – “no indication to reach cecum” should be reworded.
c. Table 2 –The time metric for the intubation time should be included – this is in
minutes?
d. The last sentence in the statistics section seems incomplete.
3. Discretionary Revisions
Level of interest: An article of limited interest
Quality of written English: Acceptable
Statistical review: Yes, and I have assessed the statistics in my report.
Declaration of competing interests:
I declare that I have no competing interests
Reviewer's report
Title:Gastronet survey on the use of one- or two-person technique for
colonoscopy insertion
Version: 1Date:28 March 2011
Reviewer: Chyke A Doubeni
Reviewer's report:
Summary:
This is a well-written brief report comparing two colonoscopy techniques: one- vs.
two-person insertion of the colonoscope. In the latter technique, the
colonoscopist directs an assistant to insert the colonoscope while presumably
freeing the colonoscopist to focus on directing the insertion and inspecting the
lumen. As noted by Hoff and colleagues, and in my discussions with some
clinical experts, the 2-person technique is less frequently practiced in the age of
the flexible colonoscope.
The study found that the two-person technique is practiced by 13 (17%) in 6
centers, with both techniques practiced at 5 of those 6 centers. Colonoscopist
using the one-person technique had a higher volume than two-person
Only univariate analyses were performed making it difficult to decipher whether
the reported differences are the result of some unmeasured characteristic or the
practice setting or patient characteristics. Compared to the one-person
technique, cecal intubation better, polyp detection rate lower and intubation time
shorter and use of sedation lower for patients undergoing colonoscopy by
2-person technique.
However, the distinction between one- and two-person techniques may be
difficult to discern in some procedures because circumstances may necessitate
the need for assistance in inserting or advancing the colonoscope even in the
one-person technique.
Therefore, the study appears to have compared the outcomes for colonoscopists
who predominantly perform a one-person to those who performed a two-person
technique. Because some of the colonoscopists switched between techniques,
and the actual technique used for each patient respondent were not determined,
it is difficult to conclude that the results represent the actual merits of the two
techniques. It is possible that the types of patients in the 2-arms are different.
Without additional data, it is difficult to conclude that the variation in polyp
detection rate is not due to some extraneous factor.
1. Major Compulsory Revisions
a. There may be a selection bias, when one looks at respondents compared to
non-respondents. The authors may have missed the opportunity to survey not
just colonoscopists, but also their principal assistants, which would have provided
data on those with missing survey data. It seems feasible to call the centers that
did not respond to get additional data on the most commonly used technique.
b. Another question that is not answered by the study is the costs/resources for
the two techniques. Is the 2-person technique using more resources for fewer
colonoscopies? Does the two-person technique use more staff? Or are the staff
just being used in a different way?
c. A central issue in the paper is the “so what” question. The authors’ explanation
for the findings suggests that there may be merits of both techniques. What this
suggests to me is the need for a qualitative study to provide context on the
differences in the quality outcomes.
d. It is quite possible, and even likely, that the variations may result from factors
other than technique. The authors should provide additional information on what
those factors could be.
e. The discussion section is highly speculative. It should be shortened particularly
the first paragraph.
f. The authors suggest that 2-persontechnique is a “more team-building concept.”
There were no data provided to support that statement and will recommend
removing or modifying that statement.
g. The limitations section ought to acknowledge that the study was not able to
determine which of the two techniques was used for each individual patient but
applied a characteristic of the colonoscopist to each patient treated by him/her.
2. Minor Essential Revisions
a. The title does not seem to reflect what was studied. Does this mean that with
either technique an assistant was not used during withdrawal?
b. Table 2 – “no indication to reach cecum” should be reworded.
c. Table 2 –The time metric for the intubation time should be included – this is in
minutes?
d. The last sentence in the statistics section seems incomplete.
3. Discretionary Revisions
Level of interest: An article of limited interest
Quality of written English: Acceptable
Statistical review: Yes, and I have assessed the statistics in my report.
Declaration of competing interests:
I declare that I have no competing interests
Please review this paper.
user
Reviewer's report
Title:Gastronet survey on the use of one- or two-person technique for
colonoscopy insertion
Version: 1Date:28 March 2011
Reviewer: Chyke A Doubeni
Reviewer's report:
Summary:
This is a well-written brief report comparing two colonoscopy techniques: one- vs.
two-person insertion of the colonoscope. In the latter technique, the
colonoscopist directs an assistant to insert the colonoscope while presumably
freeing the colonoscopist to focus on directing the insertion and inspecting the
lumen. As noted by Hoff and colleagues, and in my discussions with some
clinical experts, the 2-person technique is less frequently practiced in the age of
the flexible colonoscope.
The study found that the two-person technique is practiced by 13 (17%) in 6
centers, with both techniques practiced at 5 of those 6 centers. Colonoscopist
using the one-person technique had a higher volume than two-person
Only univariate analyses were performed making it difficult to decipher whether
the reported differences are the result of some unmeasured characteristic or the
practice setting or patient characteristics. Compared to the one-person
technique, cecal intubation better, polyp detection rate lower and intubation time
shorter and use of sedation lower for patients undergoing colonoscopy by
2-person technique.
However, the distinction between one- and two-person techniques may be
difficult to discern in some procedures because circumstances may necessitate
the need for assistance in inserting or advancing the colonoscope even in the
one-person technique.
Therefore, the study appears to have compared the outcomes for colonoscopists
who predominantly perform a one-person to those who performed a two-person
technique. Because some of the colonoscopists switched between techniques,
and the actual technique used for each patient respondent were not determined,
it is difficult to conclude that the results represent the actual merits of the two
techniques. It is possible that the types of patients in the 2-arms are different.
Without additional data, it is difficult to conclude that the variation in polyp
detection rate is not due to some extraneous factor.
1. Major Compulsory Revisions
a. There may be a selection bias, when one looks at respondents compared to
non-respondents. The authors may have missed the opportunity to survey not
just colonoscopists, but also their principal assistants, which would have provided
data on those with missing survey data. It seems feasible to call the centers that
did not respond to get additional data on the most commonly used technique.
b. Another question that is not answered by the study is the costs/resources for
the two techniques. Is the 2-person technique using more resources for fewer
colonoscopies? Does the two-person technique use more staff? Or are the staff
just being used in a different way?
c. A central issue in the paper is the “so what” question. The authors’ explanation
for the findings suggests that there may be merits of both techniques. What this
suggests to me is the need for a qualitative study to provide context on the
differences in the quality outcomes.
d. It is quite possible, and even likely, that the variations may result from factors
other than technique. The authors should provide additional information on what
those factors could be.
e. The discussion section is highly speculative. It should be shortened particularly
the first paragraph.
f. The authors suggest that 2-persontechnique is a “more team-building concept.”
There were no data provided to support that statement and will recommend
removing or modifying that statement.
g. The limitations section ought to acknowledge that the study was not able to
determine which of the two techniques was used for each individual patient but
applied a characteristic of the colonoscopist to each patient treated by him/her.
2. Minor Essential Revisions
a. The title does not seem to reflect what was studied. Does this mean that with
either technique an assistant was not used during withdrawal?
b. Table 2 – “no indication to reach cecum” should be reworded.
c. Table 2 –The time metric for the intubation time should be included – this is in
minutes?
d. The last sentence in the statistics section seems incomplete.
3. Discretionary Revisions
Level of interest: An article of limited interest
Quality of written English: Acceptable
Statistical review: Yes, and I have assessed the statistics in my report.
Declaration of competing interests:
I declare that I have no competing interests
assistant