Anatomical framework for pre-operative planning of laparoscopic left-sided colorectal surgery: Potential relevance of the distance between the inferior mesenteric artery and inferior mesenteric vein

BACKGROUND

The medial-to-lateral approach is favored by most colorectal surgeons for laparoscopic retroperitoneal dissection and mobilisation of the left colon. The peritoneal access window, i.e. the distance between the inferior mesenteric vein (IMV) and inferior mesenteric artery (IMA) must be large enough to perform the procedure safely and successfully. However, studies investigating the IMA-IMV distance and factors affecting this variable, are scarce. Therefore, we examined the IMA-IMV and D3-IMA distances to determine an anatomical framework on planning and adapting surgical therapy.

BASIC PROCEDURES

The IMA-IMV and D3-IMA distances were retrospectively measured in 230 patients (127 Male/103 Female, Median Age=54.5) who had undergone pre-operative CT-scanning before laparoscopic left-sided colorectal surgery. Two observers rated the images and interrater reliability was calculated. Subgroup, simple and multiple linear regression analyses were performed in order to detect potential interaction between morphometric variables and IMA-IMV distance.

MAIN FINDINGS

We demonstrated a significant correlation between the inferior margin of the duodenum and the origin of IMA. Determination of the IMA-IMV distance was simple and reproducible. Approximately 45% of patients undergoing laparoscopic colorectal procedures had a narrow distance (≤50mm). There was a sexual dimorphism in IMA-IMV distance, being consistently large in males. There were no other pre-operative factors which predicted whether the peritoneal dissection window for a medial-to-lateral approach was sufficient.

CONCLUSIONS

Our results provide new data for a better understanding of metric variations in abdominal vascular structures and complement previous observations. In view of our results, we recommend pre-operative measurement of the IMA-IMV before colorectal surgery where the medial-to-lateral approach is planned. Given that a narrow distance may predict a difficult dissection, this factor should be taken into account to determine the optimal surgical approach in each patient.

Evaluation of the impact of Tacrolimus-based immunosuppression on Heidelberg liver transplant cohort (HDTACRO): Study protocol for an investigator initiated, non-interventional prospective study

BACKGROUND

Tacrolimus-based immunosuppression has resulted in enormous improvements on liver transplantation (LTx) outcomes. However, dose adjustment and medication adherence play a key role in post-transplant treatment success. The aim of the present study is to assess the trough levels and the need for adaptation of therapeutic doses in de novo LTx patients treated with Tacrolimus in the clinical routine, without any intervention to the treatment regimen.

METHODS AND ANALYSIS

This is a pilot, prospective, exploratory, monocentric, non-interventional and non-randomized investigator-initiated study. Prospectively maintained data of 100 patients treated with various oral Tacrolimus-based immunosuppressants (Prograf or Envarsus) will be analyzed. The number of required dose adjustments of Tacrolimus formulations used in clinical routine for achieving the target trough level, Tacrolimus trough level, Tacrolimus dosing, concentration/dose ratio, routine laboratory tests, efficacy data (incl. survival, acute rejection, re-transplantation), patients therapy adherence, and infections requiring the need to reduce individual immunosuppressant dosing will be evaluated for each patient.

RESULT

This study will evaluate the trough levels and the need for adaptation of therapeutic doses in de novo LTx patients treated with Tacrolimus in the clinical routine, without any intervention to the treatment regimen.

CONCLUSION

The HDTACRO study will be the first study to systematically and prospectively evaluate various oral Tacrolimus-based immunosuppressants in de novo liver transplanted patients. If a difference between the therapy-subgroups is evident at the end of the trial, a randomized control trial will eventually be designed. Registration number: ClinicalTrials.gov: NCT04444817.