Automatic muscle impedance and nerve analyzer (AMINA) as a novel approach for classifying bioimpedance signals in intraoperative pelvic neuromonitoring.

Frequent complications arising from low anterior resections include urinary and fecal incontinence, as well as sexual disorders, which are commonly associated with damage to the pelvic autonomic nerves during surgery. To assist the surgeon in preserving pelvic autonomic nerves, a novel approach for intraoperative pelvic neuromonitoring was investigated that is based on impedance measurements of the innervated organs. The objective of this work was to develop an algorithm called AMINA to classify the bioimpedance signals, with the goal of facilitating signal interpretation for the surgeon. Thirty patients included in a clinical investigation underwent nerve-preserving robotic rectal surgery using intraoperative pelvic neuromonitoring. Contraction of the urinary bladder and/or rectum, triggered by direct stimulation of the innervating nerves, resulted in a change in tissue impedance signal, allowing the nerves to be identified and preserved. Impedance signal characteristics in the time domain and the time-frequency domain were calculated and classified to develop the AMINA. Stimulation-induced positive impedance changes were statistically significantly different from negative stimulation responses by the percent amplitude of impedance change Amax in the time domain. Positive impedance changes and artifacts were distinguished by classifying wavelet scales resulting from peak detection in the continuous wavelet transform scalogram, which allowed implementation of a decision tree underlying the AMINA. The sensitivity of the software-based signal evaluation by the AMINA was 96.3%, whereas its specificity was 91.2%. This approach streamlines and automates the interpretation of impedance signals during intraoperative pelvic neuromonitoring.

Technical aspects of a new approach to intraoperative pelvic neuromonitoring during robotic rectal surgery.

It has been found that rectal surgery still leads to high rates of postoperative urinary, fecal, or sexual dysfunction, which is why nerve-sparing surgery has gained increasing importance. To improve functional outcomes, techniques to preserve pelvic autonomic nerves by identifying anatomic landmarks and implementing intraoperative neuromonitoring methods have been investigated. The objective of this study was to transfer a new approach to intraoperative pelvic neuromonitoring based on bioimpedance measurement to a clinical setting. Thirty patients (16 male, 14 female) involved in a prospective clinical investigation (German Clinical Trials Register DRKS00017437, date of first registration 31/03/2020) underwent nerve-sparing rectal surgery using a new approach to intraoperative pelvic neuromonitoring based on direct nerve stimulation and impedance measurement on target organs. Clinical feasibility of the method was outlined in 93.3% of the cases. Smooth muscle contraction of the urinary bladder and/ or the rectum in response to direct stimulation of innervating functional nerves correlated with a change in tissue impedance compared with the pre-contraction state. The mean amplitude (Amax) of positive signal responses was Amax = 3.8%, negative signal responses from a control tissue portion with no stimulation-induced impedance change had an amplitude variation of 0.4% on average. The amplitudes of positive and negative signal responses differed significantly (statistical analysis using two-sided t-test), allowing the nerves to be identified and preserved. The results indicate a reliable identification of pelvic autonomic nerves during rectal surgery.

Resection rectopexy as part of the multidisciplinary approach in the management of complex pelvic floor disorders.

Objectives: Pelvic floor disorders are frequently caused by an organ prolapse involving multiple pelvic floor compartments. In such cases, a multidisciplinary strategy for diagnostic work-up and therapy is required. Methods: All patients who underwent transabdominal rectopexy/resection rectopexy alone or in combination with simultaneous gynecological pelvic floor reconstruction at our institution between 01/2006 and 12/2021 were included in this retrospective study. The study aimed to evaluate the functional outcome and postoperative complications. Results: Two hundred and eighty seven patients were assigned to one of the following groups: PG1 - patient group one: after resection rectopexy (n=141); PG2 - after ventral rectopexy (n=8); PG3 - after combined resection rectopexy and sacro (cervico)colpopexy (n=62); PG4 - after combined resection rectopexy and trans-vaginal pelvic floor repair (n=76). The duration of follow-up was 14 months for PG1 (median, IQR 37 months), 11 months for PG2 (mean, SD 9 months), 7 months for PG 3 (median, IQR 33 months), and 12 months for PG 4 (median, IQR 51 Months). The surgical procedure resulted in improvement of symptoms related to obstructed defecation in 56.4 % (22/39) of the patients in PG1, 25 % in PG2 (1/4), 62.5 % (20/32) in PG3, and 71.8 % (28/39) in PG4. "De novo" constipation was reported by 2.4 % (2/141) of patients from PG1. Improvement in fecal incontinence symptoms was reported by 69 % (40/58) of patients in PG1, 100 % in PG2 (2/2), 93.1 % (27/29) in PG3, and 87.2 % (34/39) in PG4. The recurrence rate for external rectal prolapse was 7.1 % in PG1, 50 % in PG2 (1/2), 2.7 % in PG3, and 6.3 % in PG4. A significant difference in terms of severe morbidity (grade ≥ IIIb) and mortality could not be determined between the non-interdisciplinary (PG1 with PG2) and interdisciplinary surgery (PG3 with PG4) (p=0.88, p=0.499). Conclusions: Based on our results, we can assume that combined surgery is as feasible as rectal surgery alone. In our study, combined interventions were effective and not associated with an increased risk of postoperative complications.

[Stoma-associated complications-Prevention strategy and treatment concepts]. / Stomaassoziierte Komplikationen ­ Vermeidungsstrategie und Therapiekonzepte.

Postoperative complications after the creation of an intestinal stoma have a considerable impact on the patient's quality of life. The accurate surgical technique is very important for their prevention and requires profound surgical knowledge as well as sufficient experience. The importance of the preoperative consultation as well as the postoperative care by stoma therapists is clearly proven. Depending on the severity of the complication, outpatient conservative treatment is initially indicated. A surgical local revision or laparotomy should only be considered if conservative treatment is no longer sufficient, whereby the indications for surgery should be set very cautiously. This article provides an overview of the current evidence regarding the prevention and treatment of postoperative stoma complications.

Intraoperative fluorescence angiography with indocyanine green: retrospective evaluation and detailed analysis of our single-center 5-year experience focused on colorectal surgery.

OBJECTIVES: Assessing bowel perfusion with indocyanine green fluorescence angiography (ICG-FA) shows positive effects on anastomotic healing in colorectal surgery. METHODS: A retrospective evaluation of 296 colorectal resections where we performed ICG-FA was undertaken from January 2014 until December 2018. Perfusion of the bowel ends measured with ICG-FA was compared to the visual assessment before and after performing the anastomosis. According to the observations, the operative strategy was confirmed or changed. Sixty-seven low anterior rectal resections (LARs) and 76 right hemicolectomies were evaluated statistically, as ICG-FA was logistically not available for every patient in our service and thus a control group for comparison resulted. RESULTS: The operative strategy based on the ICG-FA results was changed in 48 patients (16.2%), from which only one developed an anastomotic leakage (AL) (2.1%). The overall AL rate was calculated as 5.4%. Within the 67 patients with LAR, the strategy was changed in 11 patients (16.4%). No leakage was seen in those. In total three AL happened (4.5%), which was three times lower than the AL rate of 13.6% in the control group but statistically not significant. From the 76 right hemicolectomies a strategy change was undertaken in 10 patients (13.2%), from which only one developed an AL. This was the only AL reported in the whole group (1.3%), which was six times lower than the leakage rate of the control group (8.1%). This difference was statistically significant (p=0.032). CONCLUSIONS: Based on the positive impact by ICG-FA on the AL rate, we established the ICG-FA into our clinical routine. Although randomized studies are still missing, ICG-FA can raise patient safety, with only about 10 min longer operating time and almost no additional risk for the patients.

The modified Blumgart anastomosis after pancreaticoduodenectomy: a retrospective single center cohort study.

OBJECTIVES: The postoperative pancreatic fistula (POPF) is a major complication after pancreatic head resection whereby the technique of the anastomosis is a very influencing factor. The literature describes a possible protective role of the Blumgart anastomosis. METHODS: Patients after pancreatic head resection with reconstruction through the modified Blumgart anastomosis (a 2 row pancreatic anastomosis through mattress sutures of the parenchyma and duct to mucosa pancreaticojejunostomy, Blumgart-group) were compared with patients after pancreatic head resection and reconstruction through the conventional pancreatojejunostomy (single suture technique of capsule and parenchyma to seromuscularis, PJ-group). The Data were collected retrospectively. Depending on the propensity score matching in a ratio of 1:2 comparison groups were set up. Blumgart-group (n=29) and PJ-group (n=56). The primary end point was the rate of POPF. Secondary goals were duration of operation, length of hospital stay, length of stay on intermediate care units and hospital mortality. RESULTS: The rate of POPF (biochemical leak, POPF "grade B" and POPF "grade C") was less in the Blumgart-group, but without statistical relevance (p=0.23). Significantly less was the rate of POPF "grade C" in the Blumgart-group (p=0.03). Regarding the duration of hospital stay, length of stay on intermediate care units and hospital mortality, there was no relevant statistical difference between the groups (p=0.1; p=0.4; p=0.7). The duration of the operation was significantly less in the Blumgart-group (p=0.001). CONCLUSIONS: The modified Blumgart anastomosis technique may have the potential to decrease major postoperative pancreatic fistula.

[Influence of Local Insufflation of Warm Humidified CO2 on the Wound Surface and Body Core Temperature as well as on Wound Healing in Open Colorectal Surgery]. / Einfluss einer lokalen Insufflation von befeuchtetem und erwärmtem CO2 auf die Wundoberflächen- und Körperkerntemperatur sowie auf die Wundheilung in der offenen Kolorektalchirurgie.

BACKGROUND: Perioperative hypothermia may lead to serious complications. This study aims to investigate whether intraoperative insufflation of warmed and humidified carbon dioxide (W-H-CO2) into the open wound during open colorectal surgery influences body core and wound surface temperatures or the incidence of wound healing disorders (WHD). METHODS: Between 02/2018 and 07/2019, 50 patients intended to undergo open resection for colorectal cancer were recruited and randomised to a control group (n = 25) and an experimental group (n = 25). In the experimental group, a device for insufflation of W-H-CO2 was used. Body core and wound surface temperatures were recorded at the beginning and before finishing the procedure. IL-6 serum levels were determined preoperatively and during the postoperative course. Clinical observation of wound healing was performed until the 30th day post-op. RESULTS: Both groups were homogeneous in terms of risk factors for WHD. In the control group, the median body core temperature (1. quartile/3. quartile) was 36.2 °C (36/36.4 °C) when the operation started and 36.2 °C (35.9/36.45 °C) at the end, while in the experimental group it was initially 36.2 °C (35.7/36.4 °C) and 36.4 °C (36/36.7 °C) at the end. There was no significant difference between the two groups (p = 0.08). The wound temperature in the control group dropped from 32.8 °C (median; 31.85/34.05 °C) to 30.7 °C (median; 29.85/32.15 °C). In the experimental group, we recorded a drop from 31.9 °C (median; 30.25/32.95 °C) to 31.6 °C (median; 30.25/31.85 °C), which was statistically significant (p = 0.000475). The dynamic of the IL-6 serum levels in both groups suggest that there was no significant difference (p = 0.66; p = 0.88; p = 0.88). In the control group, 8 patients experienced superficial WHD, 2 anastomotic leakages (AL), while in the experimental group, superficial WHD were observed in 5 patients and AL in 1 patient. This differences between the groups regarding in WHD were not significant (p = 0.42). CONCLUSION: The established measures for prevention of perioperative hypothermia in elective procedures are sufficient. However, the local wound surface temperature is not preserved satisfactorily. Deployment of a device for intraoperative insufflation of W-H-CO2 into open wounds may be suitable for maintaining local normothermia. Further studies are needed to determine the influence of warm and humid CO2 on wound healing.