Closing gaps - risk factors, occurrence, and treatment of abdominal wall hernias

This thesis covers a broad spectrum of new developments in abdominal wall hernia research. Prevention and recurrence, and the treatment of simple as well as complex hernias will be addressed. Part I of this thesis focuses on prevention and risk factors for development of incisional and parastomal hernias. Part II focuses on the treatment of simple abdominal wall hernias. Part III focuses on the treatment of complex incisional or primary hernias. \ud Part IV focuses on new developments in hernia research

Comparing different modalities for the diagnosis of incisional hernia: a systematic review

Purpose: Incisional hernia (IH) is the most frequent complication after abdominal surgery. The diagnostic modality, observer, definition, and diagnostic protocol used for the diagnosis of IH potentially influence the reported prevalence. The objective of this systematic review is to evaluate the diagnostic accuracy of different modalities used to identify IH. Methods: Embase, MEDLINE OvidSP, Web of Science, Google Scholar, and Cochrane databases were searched to identify studies diagnosing IH. Studies comparing the IH detection rate of two different diagnostic modalities or inter-observer variability of one modality were included. Quality assessment of studies was done by Cochrane Collaboration’s tool. Article selection and data collection were performed independently by two researchers. PROSPERO registration: CRD42017062307. Results: Fifteen studies representing a total of 2986 patients were included. Inter-observer variation for CT-scan ranged from 11.2 to 69% (n = 678). Disagreement between ultrasound and CT-scan ranged between 6.6 and 17% (n = 221). Ten studies compared physical examination to CT-scan or ultrasound. Disagreement between physical examination and imaging ranged between 7.6 and 39% (n = 1602). Between 15 and 58% of IHs were solely detected by imaging (n = 483). Relative increase in IH prevalence for imaging compared to physical examination ranged from 0.92 to 2.4 (n = 1922). Conclusions: Ultrasound or CT-scan will result in substantial additional IH diagnosis. Lack of consensus regarding the definition of IH might contribute to the disagreement rates. Both the observer and diagnostic modality used could be additional factors explaining varia

Sarcomania? The Inapplicability of Sarcopenia Measurement in Predicting Incisional Hernia Development

Background: Incisional hernia is a frequent complication after abdominal surgery. A risk factor for incisional hernia, related to body composition, is obesity. Poor skeletal muscle mass might also be a risk factor, as it may result in weakness of the abdominal wall. However, it remains unknown if sarcopenia (i.e. low skeletal muscle mass) is a risk factor for incisional hernia. Therefore, this study aims to investigate whether a relation between sarcopenia and incisional hernia exists. Methods: Patients from the STITCH trial, who underwent elective midline laparotomy, were included. Computed tomography examinations performed within 3 months preoperatively were used to measure the skeletal muscle index (SMI; cm2/m2). Primarily, SMI measured continuously, sarcopenia based on previously described cut-off values for the SMI, and sarcopenia as the lowest gender-specific SMI quartile were assessed as measures to predict incisional hernia occurrence. Secondary, the association between these three measures and post-operative complications was investigated. Results: In total, 283 patients (45.2% male; mean age 63.7 years; mean BMI 25.36 kg/m2) were included, of whom 52 (18%) devel

Comparison of different modalities for the diagnosis of parastomal hernia: a systematic review

Purpose: Parastomal hernia (PSH) is a common complication following stoma formation. The incidence of PSH varies widely due to several factors including differences in diagnostic modality, observer, definition, and classification used for diagnosing PSH. The aim of this systematic review was to evaluate the diagnostic accuracy of the modalities used to identify PSH. Methods: Embase, MEDLINE, Cochrane, Web of Science, and Google Scholar databases were searched. Studies reporting PSH incidence rates detected by two or more different diagnostic modalities or inter-observer variation on one diagnostic modality were included. Article selection and assessment of study quality were conducted independently by two researchers using Cochrane Collaboration’s tool for assessing risk of bias. PROSPERO registration: CRD42018112732. Results: Twenty-nine studies (n = 2514 patients) were included. Nineteen studies compared CT to clinical examination with relative difference in incidence rates ranging from 0.64 to 3.0 (n = 1369). Overall, 79% of studies found an increase in incidence rate when using CT. Disagreement between CT and clinical examination ranged between 0 and 37.3% with pooled inter-modality agreement Kappa value of 0.64 (95% CI 0.52–0.77). Four studies investigated the diagnostic accuracy of ultrasonography (n = 103). Compared with peroperative diagnosis, CT and ultrasonography both seemed accurate imaging modalities with a sensitivity of 83%. Conclusion: CT is an accurate diagnostic modality for PSH diagnosis and increases PSH detection rates, as compared with clinical examination. Studies that specially focus on the diagnostic accuracy are needed and should aim to take patient-reported outcomes into account. A detailed description of the diagnostic approach, modality, definition, and involved observers is prerequisite for future PSH research

Risk Factors for Incarceration in Patients with Primary Abdominal Wall and Incisional Hernias: A Prospective Study in 4472 Patients

_Background_ Incarceration of primary and incisional hernias often results in emergency surgery. The objective of this study was to evaluate the relation of defect size and location with incarceration. Secondary objectives comprised identification of additional patient factors associated with an incarcerated hernia. _Methods_ A registry-based prospective study was performed of all consecutive patients undergoing hernia surgery between September 2011 and February 2016. Multivariate logistic regression was performed to identify risk factors for incarceration. _Results_ In total, 83 (3.5%) of 2352 primary hernias and 79 (3.7%) of 2120 incisional hernias had a non-reducible incarceration. For primary hernias, a defect width of 3–4 cm compared to defects of 0–1 cm was significantly associated with an incarcerated hernia (OR 2.85, 95% CI 1.57–5.18, p = 0.0006). For incisional hernias, a defect width of 3–4 cm compared to defects of 0–2 cm was significantly associated with an incarceration (OR 2.14, 95% CI 1.07–4.31, p = 0.0324). For primary hernias, defects in the peri- and infra-umbilical region portrayed a significantly increased odds for incarceration as compared to supra-umbilical defects (OR 1.98, 95% CI 1.02–3.85, p = 0.043). Additionally, in primary hernias age, BMI, and constipation were associated with incarceration. In incisional hernias age, BMI, female sex, diabetes mellitus and ASA classification were associated with incarceration. _Conclusion_ For primary and incisional hernias, mainly defects of 3–4 cm were associated with incarceration. For primary hernias, mainly defects located in the peri- and infra-umbilical region were associated with incarceration. Based on patient and hernia characteristics, patients with increased odds for incarceration may be selected and these patients may benefit from elective surgical treatment

Meta-analysis evaluating music interventions for anxiety and pain in surgery

Background: This study aimed to evaluate anxiety and pain following perioperative music interventions compared with control conditions in adult patients. Methods: Eleven electronic databases were searched for full-text publications of RCTs investigating the effect of music interventions on anxiety and pain during invasive surgery published between 1 January 1980 and 20 October 2016. Results and data were double-screened and extracted independently. Random-effects meta-analysis was used to calculate effect sizes as standardized mean differences (MDs). Heterogeneity was investigated in subgroup analyses and metaregression analyses. The review was registered in the PROSPERO database as CRD42016024921. Results: Ninety-two RCTs (7385 patients) were included in the systematic review, of which 81 were included in the meta-analysis. Music interventions significantly decreased anxiety (MD -0·69, 95 per cent c.i. -0·88 to -0·50; P<0·001) and pain (MD -0·50, -0·66 to -0·34; P<0·001) compared with controls, equivalent to a decrease of 21mm for anxiety and 10mm for pain on a 100-mm visual analogue scale. Changes in outcome corrected for baseline were even larger: MD -1·41 (-1·89 to -0·94; P<0·001) for anxiety and -0·54 (-0·93 to -0·15; P=0·006) for pain. Music interventions provided during general anaesthesia significantly decreased pain compared with tha

Hyperbaric oxygen therapy improves colorectal anastomotic healing

Purpose: Hyperbaric oxygen treatment (HBOT) has been found to improve the healing of poorly oxygenated tissues. This study aimed to investigate the influence of HBOT on the healing in ischemic colorectal anastomosis. Methods: Forty Wistar rats were randomly divided into a treatment group that received HBOT for 10 consecutive days (7 days before and 3 days after surgery), or in a control group, which did not receive the therapy. Colectomy with an ischemic anastomosis was performed in all rats. In each group, the rats were followed for 3 or 7 days after surgery to determine the influence of HBOT on anastomotic healing. Results: Five rats from each group died during follow-up. No anastomotic dehiscence was seen in the HBOT group, compared to 37.5 % and 28.6 % dehiscence in the control group on postoperative day (POD) 3 and 7, respectively. The HBOT group had a significantly higher bursting pressure (130.9 ± 17.0 mmHg) than the control group (88.4 ± 46.7 mmHg; p = 0.03) on POD 3. On POD 3 and POD 7, the adhesion severity was significantly higher in the control groups than in the HBOT groups (p < 0.005). Kidney function (creatinine level) of the HBOT group was significantly better than of the control group on POD 7 (p = 0.001). Interestingly, a significantly higher number of CD206+ cells (marker for type 2 macrophages) was observed in the HBOT group at the anastomotic area on POD 3. Conclusion: Hyperbaric oxygen enhanced the healing of ischemic anastomoses in rats and improved the postoperative kidney function

Incidence, risk factors and prevention of stoma site incisional hernias

Aim: Stoma reversal might lead to a stoma site incisional hernia. Recently, prophylactic mesh reinforcement of the stoma site has gained increased attention, supporting the need for accurate data on the incidence of and risk factors for stoma site incisional hernia and to identify high-risk patients. The aim of this study was to assess incidence, risk factors and prevention of stoma site incisional hernias. Method: Embase, MEDLINE, Web of Science, Cochrane and Google Scholar databases were searched. Studies reporting the incidence of stoma site incisional hernia after stoma reversal were included. Study quality was assessed with the Newcastle–Ottawa Scale and Cochrane risk of bias tool. Data on incidence, risk factors and prophylactic mesh reinforcement were extracted. Results: Of 1440 articles found, 33 studies comprising 4679 reversals were included. The overall incidence of incisional hernia was 6.5% [range 0%–38%, median follow-up 27.5 (17.54–36) months]. Eleven studies assessed stoma site incisional hernia as the primary end-point, showing an incidence of 17.7% [range 1.7%–36.1%, median follow-up 28 (15.25–51.70) months]. Body mass index, diabetes and surgery for malignant disease were found to be independent risk factors, as derived from eight studies. Two retrospective comparative cohort studies showed significantly lower rates of stoma site incisional hernia with prophylactic mesh reinforcement compared with nonmesh controls [6.4% vs 36.1% (P = 0.001); 3% vs 19% (P = 0.04)]. Conclusion: Stoma site incisional hernia should not be underestimated as a long-term problem. Body mass index, diabetes and malignancy seem to be potential risk factors. Currently, limited data are available on the outcomes of prophylactic mesh reinforcement to prevent stoma site incisional hernia

Zinc-Impregnated Mesh for Abdominal Wall Repair Reduces Infection in a Rat Model of Peritonitis

Background: The objective of this study was to assess whether a zinc-impregnated polypropylene mesh (ZnMesh) has better antibacterial properties in a contaminated environment compared with a regular polypropylene mesh. Materials and methods: Thirty-eight Wistar Han rats underwent cecal ligation and puncture to induce peritonitis 24 h before implantation of an intraperitoneal ZnMesh or a regular polypropylene mesh. Primary outcome was the number of colony forming units (CFU) per sample (mesh and abdominal wall). Secondary outcomes were macroscopic (incorporation of mesh, abscesses, and adhesions on mesh surface) and histological (inflammatory cell reaction, mesh-specific parameters, and collagen deposition) parameters. All outcomes were evaluated after 30 and 90 d. Results: After 30 d, no significant difference in CFU per sample was present between the ZnMesh and control groups. After 90 d, a lower number of CFU per sample was present in the ZnMesh group compared with the control group (trypticase soy agar with 5% sheep blood: 0 log10 CFU/sample IQR: 0-1.40 versus 1.58 log10 CFU/sample IQR: 0-4.30, P = 0.012; MacConkey: 0 log10 CFU/sample IQR: 0-2.65 versus 1.18 log10 CFU/sample IQR: 0-4.04, P = 0.438). After 90 d, the percentage of adhesions on mesh surface was significantly higher in the ZnMesh group (95% IQR: 60%-100% versus 50% IQR: 23%-75%, P = 0.029). No differences were seen in other macroscopic outcomes or histology. Conclusions: A significantly lower number of CFU per sample was found in the ZnMesh group after 90 d. After 30 d, no statistically significant differences in CFU per sample were seen. This result suggests that the ZnMesh group has better antibacterial properties in a contaminated environment. However, this is at the cost of a significantly higher percentage of adhesions