Value of lymph node dissection in intrahepatic cholangiocarcinoma: a systematic review and meta-analysis

BACKGROUND

The aim of this study was to perform a systematic review and meta-analysis to investigate the impact of lymph node dissection (LND) on outcomes following resection of intrahepatic cholangiocarcinoma (ICC).

METHODS

PubMed, EMBASE, and Cochrane were searched from inception to 30th January 2023 for studies that compared LND with no LND (NLND) among patients with ICC. To limit the effect of unbalanced covariates, only studies that utilized propensity score-based methods were included. Subgroup analysis of patients with clinically node-negative (cN0) ICC was analyzed.

RESULTS

Among 3776 patients with ICC, individuals in the LND versus NLND cohorts had comparable overall survival (OS) (Hazard ratio [HR] 0.78, 95 % confidence interval [CI] 0.57-1.06, P = 0.11), disease-free survival (DFS) (HR 0.84, 95 % CI 0.70-1.01, P = 0.07) and risk of major complications (odds ratio [OR] 1.07, 95 % CI 0.70-1.62, P = 0.75). Subgroup analysis of cN0 patients, OS was significantly higher in patients who underwent LND (HR 0.61, 95 % CI 0.50-0.74, P < 0.01), with a non-significant trend towards improved DFS (HR 0.81, 95 % CI 0.65-1.01, P = 0.06).

CONCLUSION

This study found no differences in long-term survival or morbidity following LND for ICC. Subgroup analysis of cN0 patients, who underwent LND detected improved OS with a trend towards better DFS, compared to patients with NLND.

Cloquet's node trumps imaging modalities in the prediction of pelvic nodal involvement in patients with lower limb melanomas in Asian patients with palpable groin nodes

Patients with clinically palpable lymph node metastases to the groin are treated with groin dissection to control local disease and stage the malignancy. However, the extent of nodal dissection required to optimize survival rate is controversial.

AIM

To evaluate the approach to the extent of nodal dissection in advanced lower limb melanomas with clinically palpable inguinal nodes; to review survival outcomes based on the extent of nodal dissection and nodal disease.

MATERIALS AND METHODS

A prospectively maintained database of 12 patients with lower limb melanoma was analyzed. Cloquet's node was assessed based on the frozen section result which guided the decision to proceed to iliac-obturator dissection. The correlation of the results of the Cloquet's nodes and radiological imaging to the final histological outcome of groin nodal dissection were compared.

RESULTS

The positive predictive value (PPV) of radiological imaging in identifying pelvic nodal disease was 60%. PPV of a positive or indeterminate frozen section result of Cloquet's node was 71.4%. Notably, all patients with a positive frozen section result for the Cloquet's node had positive pelvic nodal disease. Median DFS for all patients is 26 months (range 3-68 months) and the median OS for all patients is 28.5 months (range 5-68 months). Median DFS for node negative patients was 28 months (range 24-68 months). Median DFS for node positive patients was 20 months (range 3-36 months).

CONCLUSION

Cloquet's node was shown to be superior to radiological imaging and should be preferentially used to decide on the extent of nodal dissection.

Assessment of surgical trainees' quality of knot-tying

BACKGROUND

This study aimed to assess surgical trainees' knot tying technique and determine the type and security of knots created.

METHODS

Twenty-five participants were requested to tie 40 knots each, using Vicryl 2-0 and Prolene 2-0 sutures. With each suture material, the participants tied: in series 1, 4 knots as they would normally do during surgery; in series 2, 4 knots with 3 throws, 4 knots with 4 throws, 4 knots with 5 throws, and 4 knots with 6 throws. All knots were tested for tensile strength using a tensiometer. Knots with tensile strength of less than 5 N were considered dangerous.

RESULTS

Of the 25 participants, 2 created square knots consistently, 2 created a mixture of square and slip knots, and 21 created only slip knots. Square knots accounted for only 12.8% of all the knots. The incidence of knot slipping under tension was significantly lower with square knots (p < 0.001). Square knots had significantly higher tensile strength than slip knots (p < 0.001). For Vicryl, 4-throw square knots were superior to 6-throw slip knots (p < 0.001). For Prolene, 3-throw square knots were superior to 6-throw slip knots (p = 0.035). Some 12.6% of Vicryl knots and 5.6% of Prolene knots were dangerous and all of these were slip knots with up to 6 throws. Three out of 12 participants who thought they had created square knots actually created square knots and the rest produced slip knots. The participants' surgical experience did not have any correlation with their knot security (r = -0.044, p = 0.833).

CONCLUSIONS

Knot tying is often executed with technical errors resulting in slip knots with less than optimal security and high incidence of dangerous knots. Tensiometry testing could be used as an objective assessment tool for knot-tying competency for surgical trainees.

A microfluidic mixer with self-excited 'turbulent' fluid motion for wide viscosity ratio applications

In micromixer studies, compared with the design, modeling and characterization, the influence of the fluid properties on mixing has been less discussed. This topic is of practical significance as the properties of diverse biological and chemical liquids to be mixed have large variations. Here, we report a microfluidic mixer for mixing fluids with widely different viscosities. It contains an interconnected multi-channel network through which the bulk fluid volumes are divided into smaller ones and chaotically reorganized. Then, the multiple fluid streams are driven into an expansion chamber which triggers viscous flow instabilities. Experiments with the co-flow of glycerol and aqueous solutions show an automatic transition of the flow from a steady state to a 'turbulent' state, significantly enhancing the mixing. This observation is rather interesting considering that it occurs in a passive flow and the average Reynolds number involved is small. Further testing indicates that this mixer works well at viscosity ratio (chi) up to the order of 10(4).