Review for 10.1186/s12876-024-03474-7 (2024)

Title: Diagnostic value of T-tube cholangiography and choledochoscopy in residual calculi after
biliary surgery
Version: 3 Date: 23 Jul 2024
Reviewer:  Mohamad Raafat
Reviewer's report:
Thank you for allowing me to review the manuscript entitled “Diagnostic value of T-tube
cholangiography and choledochoscopy in residual calculi after biliary surgery, Is T-tube
cholangiography necessary before T-tube removal#”
A great effort was made by the authors to write this manuscript of an interesting topic. However,
I have some comments to be considered by the authors:
Major comments:
1. The authors recommends in the conclusion to concurrently perform T-tube cholangiography
and choledochoscopy before T-tube removal to enhance the diagnostic accuracy of residual
stones and minimize the incidence of bile duct stone remnants. However, this is not supported
by the results (no significant difference between T-tube cholangiography and choledochoscopy
in the evaluation of residual stones, P=0.82).
2. Depends on study results, It seems impractical to routinely perform choledochoscopy before
T-tube removal to avoid a false negative rate of 4.4% in case of T-tube cholangiography.
3. Leaving the patients with insitu T-tube for 6-8 weeks carries morbidity to patients and affects
their quality of life during this period which is not justified by study results and data in literature.
4. In specialized centers where choledochoscopy can be performed via T-tube tract,
choledochoscopy is usually performed during CBD exploration. Why intraoperative
choledochoscopy did miss stones that can be detected by choledochoscopy performed via T-
tube tract. This is not logic and should be explained.
5. There is a trend worldwide to enhance recovery of patients by avoiding insertion of T-tube
after CBD exploration if clearance of stone is confirmed by choledochoscopy or cholangiogram
or both. The rationale of managing CBD stones in your center should be mentioned in the context
of this trend.
6. Leaving the T-tube routinely for 6-8 weeks predispose to formation of biliary mud and new
stones.
7. Patients with asymptomatic residual stones usually have raised ALP if T-tube drainage is
closed. Unfortunately, this study lacks clinical and biochemical data of patents with residual
stones.
8. The authors describe the management in case if choledochoscopy mistakenly enters the
abdominal cavity. However, the failure rate in this study is 0 %. On which data, the authors rely?
9. The authors mentioned that they closed T-tube after two weeks. On which imaging, the authors
rely to made this critical decision.
Minor comments:
1. In background section;
- “The prevalence of cholelithiasis,……. 11% of the overall population”
Please put a reliable reference.
- “T-tube cholangiography and choledochoscopy are standard techniques for assessing residual
bile duct stones, effectively reducing the incidence of postoperative stone retention”.
Choledochoscopy via T-tube is not a standard technique.
- “Additionally, simultaneous treatment can be performed during the procedureFurther”.
Put full stop after “procedure”.
2. In methodology section;
-“Choledocholithiasis was observed in 25 cases”
Clarify if these patents already had cholecystectomy
- “Patients were discharged from the hospital after bile duct surgery”.
Mention the status of T-tube (open or closed) until readmission.
- “Patients undergoing T-tube cholangiography were positioned supine, closed the T-tube”
Do you mean opening the closed T-tube.
- “20-50 ml of 20% ioversol”
I recommend “ioversol (contrast agent)” for more clarification
- “Following extraction, a 16F silicone tube was placed…..”
How did you place a silicon tube, is it by a guide wire?
Usually a small tract like that adapts only a smaller tube than the originally placed T-tube. What
is the size of T-tube the authors used in the study.
3. In Results section;
- In Table 2. Please clarify the mean of positive, i.e. it is positive only for diagnosis of residual
stones
- “In addition, residual stones were found in….”
Some diagnoses of minimal significance i.e. inflammatory hyperplasia, cholesterol
crystallization, and biliary edema
- What is the impact of diagnosing these diseases by choledochoscopy on the final management.
4. In Discussion section;
- “The most fundamental, secure, and dependable surgical approach for stone removal is
common bile duct exploration with T-tube drainage”
This is not right in the context of recent data and trends.
- Currently, the clinical methods employed to examine residual stones encompass B-ultrasound”
Please put a reliable reference regarding B-ultrasound.
-“…driven by both economic and technical considerations”
Choledochoscopy is not economic in its maintenance.
- “In this study, the prevalence of residual calculi following biliary duct operation over the past
five years in a cohort of 287 cases was found to be 13.2%”
Why the missed stone rate is double that reported in literature.
- “Possible  causes of misdiagnosis and missed diagnosis by T-tube angiography”
Please use the term T-tube “cholangiography” in replace of angiography in whole manuscript.
-“, without waiting for sinus tract formation.”
Do you mean maturation of sinus tract?
- “……and if the sinus tract is mature”
It is a separate point of advantages.
- “furthermore, hepatolithiasis can be detected with the guide of T-tube cholangiography…”.
Please not that “hepatolithiasis” is a separate disease and has its separate management.
- What is the benefit of Fig 1 in the manuscript?
-“ These advantages include ease of operation, reduced complications, lower hospitalization
costs”
How the use of choledochoscopy leads to reduced hospitalization costs?
-“ Studies have reported a postoperative residual stone removal rate exceeding 90% with
choledochoscopy(14–16)”
Please use recent references.
-“However, it should be noted that due to its invasive nature choledochoscopy may lead to…”
Please put a reliable reference.
-“ Simultaneously, we observed mild bile turbidity with a small amount of pus moss in 73 cases
and bile containing a large amount of floccule in19 cases”
It may be a disadvantage of keeping T-tube insitu for 6-8 weeks.
“Following laparoscopic surgery, it takes a minimum of 8 weeks for the T-tube sinus tract to
mature(9)”
I see that the data the reference is not consistent with your sentence.
- “In cases with biliary peritonitis, a drainage tube  can be placed through the ostium of the
sinus tract”
Biliary peritonitis means free bile leak into the abdominal cavity which need effective drainage
especially pelvic region. Please clarify your rationale.
-“ …as well as minimize the occurrence of residual stone and the rate of reoperation.”
Do you mean to minimize the misdiagnosis of residual stones?
- “there should be a vertical distance of more than 60cm between the suspension position of the
contrast agent”
Why the authors did not use the method of injecting the contrast by a syringe (similar in ERCP).
Please clarify your rationale.