Characterisation of human posterior rectus sheath reveals mechanical and structural anisotropy.

BACKGROUND: Our work aims to investigate the mechanical properties of the human posterior rectus sheath in terms of its ultimate tensile stress, stiffness, thickness and anisotropy. It also aims to assess the collagen fibre organisation of the posterior rectus sheath using Second-Harmonic Generation microscopy. METHODS: For mechanical analysis, twenty-five fresh-frozen samples of posterior rectus sheath were taken from six different cadaveric donors. They underwent uniaxial tensile stress testing until rupture either in the transverse (n = 15) or longitudinal (n = 10) plane. The thickness of each sample was also recorded using digital callipers. On a separate occasion, ten posterior rectus sheath samples and three anterior rectus sheath samples underwent microscopy and photography to assess collagen fibre organisation. FINDINGS: samples had a mean ultimate tensile stress of 7.7 MPa (SD 4.9) in the transverse plane and 1.2 MPa (SD 0.8) in the longitudinal plane (P < 0.01). The same samples had a mean Youngs modulus of 11.1 MPa (SD 5.0) in the transverse plane and 1.7 MPa (SD 1.3) in the longitudinal plane (P < 0.01). The mean thickness of the posterior rectus sheath was 0.51 mm (SD 0.13). Transversely aligned collagen fibres could be identified within the posterior sheath tissue using Second-Harmonic Generation microscopy. INTERPRETATION: The posterior rectus sheath displays mechanical and structural anisotropy with greater tensile stress and stiffness in the transverse plane compared to the longitudinal plane. The mean thickness of this layer is around 0.51 mm - consistent with other studies. The tissue is constructed of transversely aligned collagen fibres that are visible using Second-Harmonic Generation microscopy.

The Isolation, Culture, and Cryopreservation of Human Rectus Sheath Fibroblasts.

The vast majority of pelvic and intra-abdominal surgery is undertaken through at least one incision, through either the linea alba or the rectus sheath. These connective tissue layers are formed from the aponeuroses of the rectus muscles (anterior and posterior rectus sheath) and are vital for the structural integrity of the abdominal wall. Poor healing of these connective tissues after surgery can lead to significant morbidity for patients, who can develop unsightly and painful incisional hernias. Fibroblasts within the rectus sheath are responsible for laying down and remodeling collagen during the healing process after surgery. Despite their importance for this healing process, such cells have not been studied in vitro. In order to carry out such work, researchers must first be able to isolate these cells from human tissue and culture them successfully so they may be used for experimentation. This article provides an extensive and detailed protocol for the isolation, culture, cryopreservation, and thawing of human rectus sheath fibroblasts (RSFs). In our hands, this protocol develops confluent cultures of primary fibroblasts within 2 weeks, and sufficient cultures ready for freezing and storage after a further 2 to 4 weeks. © 2023 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol: Collagenase digestion of human rectus sheath and isolation of RSFs Alternate Protocol: Collagenase digestion of human rectus sheath and isolation of RSFs, digestion in flask Support Protocol: Cryopreservation and thawing of human RSFs.

A case of perforated Meckel's diverticulitis tethered to the umbilicus associated with a urachal remnant.

Meckel's diverticulum (MD) occurs in 2% of the population and is often asymptomatic. It is an embryological remnant of the oomphalomesenteric duct and can be associated with another embryonic structure-the urachus. A 23-year-old male presented with generalized abdominal pain and fever on a background of chronic abdominal pain and recurrent urinary infections. A CT scan of the abdomen and pelvis revealed an inflamed MD. Next day, the patient deteriorated and was taken to theatre. The MD was found to be both perforated and tethered to the umbilicus, which itself was directly related to an abnormal extra-peritoneal structure-shown to be a urachal remnant. Such cases pose diagnostic and therapeutic challenges. Young males with chronic abdominal pain and recurrent urinary infections should be thoroughly investigated for such pathology. Laparoscopic approach to such cases should be undertaken with caution due to possible umbilical tethering.

A Systematic Review Examining the Experimental Methodology Behind In Vivo Testing of Hiatus Hernia and Diaphragmatic Hernia Mesh.

INTRODUCTION: Mesh implants are regularly used to help repair both hiatus hernias (HH) and diaphragmatic hernias (DH). In vivo studies are used to test not only mesh safety, but increasingly comparative efficacy. Our work examines the field of in vivo mesh testing for HH and DH models to establish current practices and standards. METHOD: This systematic review was registered with PROSPERO. Medline and Embase databases were searched for relevant in vivo studies. Forty-four articles were identified and underwent abstract review, where 22 were excluded. Four further studies were excluded after full-text review-leaving 18 to undergo data extraction. RESULTS: Of 18 studies identified, 9 used an in vivo HH model and 9 a DH model. Five studies undertook mechanical testing on tissue samples-all uniaxial in nature. Testing strip widths ranged from 1-20 mm (median 3 mm). Testing speeds varied from 1.5-60 mm/minute. Upon histology, the most commonly assessed structural and cellular factors were neovascularisation and macrophages respectively (n = 9 each). Structural analysis was mostly qualitative, where cellular analysis was equally likely to be quantitative. Eleven studies assessed adhesion formation, of which 8 used one of four scoring systems. Eight studies measured mesh shrinkage. DISCUSSION: In vivo studies assessing mesh for HH and DH repair are uncommon. Within this relatively young field, we encourage surgical and materials testing institutions to discuss its standardisation.

The Use of Botulinum Toxin in Complex Hernia Surgery: Achieving a Sense of Closure.

Abdominal wall surgeons have developed a host of tools to help facilitate fascial closure. Botulinum toxin A is one of the most recently identified treatments and has grown in popularity over recent years; showing great promise in a number of case series and cohort studies. The toxin paralyses lateral abdominal wall muscles in order to increase laxity of the tissues-facilitating medialisation of the rectus muscles. Several research groups around the world are developing expertise with its use-uncovering its potential. We present a review of the relevant literature over the last two decades, summarising the key evidence behind its indications, dosing and effects.

Monitoring photographic proof of cecal intubation: A closed-loop audit of best practice colonoscopy.

Gold standard colonoscopy in the UK demands a 90% cecal intubation (CI) rate. Endoscopists must provide photographic evidence of CI, which can include images of the terminal ileum, appendix orifice, anastomosis or ileocecal valve. Whilst photographic proof of intubation should be obtained for all complete colonoscopies, this is not routinely audited. Three hundred and ninety-six complete colonoscopies were analyzed, 200 in an initial audit, and 196 in a second audit. Photos taken during colonoscopy were reviewed for evidence of successful CI, as well as whether these photographs had been marked as "proof of intubation" (POI). Results were shared at departmental governance meetings in order to assess any improvement in practice. Initial audit revealed 70% of colonoscopies had provided sufficient proof of CI but only 50% provided photographs that were described as such. Twenty percent of colonoscopies provided sufficient images, but these were not identified as POI. Thirty percent of all colonoscopies provided insufficient proof of CI. Upon repeat audit, 71% of colonoscopies met best practice standards, with the remaining 29% showing insufficient evidence of CI. In the modern era of digital technology, lack of photographic evidence should be seen as unacceptable and may raise important clinical and medicolegal concerns. We recommend that audits such as this become standard practice to ensure best practice.

Surgical Site Infection: The Scourge of Abdominal Wall Reconstruction.

Background: Surgical site infection (SSI) is a well-recognized and potentially catastrophic complication of abdominal wall reconstruction (AWR). The authors present a review of the literature surrounding SSI in AWR, exploring prevention and treatment strategies as well as risk factors. Methods: A comprehensive review of the current literature was undertaken. Evidence was reviewed and summarized with particular focus on prevention and treatment strategies available to hernia surgeons. Results: Patient risk factors for SSI are well described in the literature and include obesity, smoking, and other comorbidities. Contaminated hernias and cases involving enterocutaneous fistulae are also at higher risk of SSI. Surgical decisions such as type of mesh, plane of mesh placement, and fascial release may all contribute to SSI risk. To treat established mesh infection, conservative management with antibiotic agents and negative pressure therapy is a reasonable option in some cases. Removal of prosthesis appears to provide favorable results, however, repeat surgery can be problematic Conclusions: Surgical site infection remains an important pathology in the world of AWR. Surgeons have a wealth of tools in their arsenal to prevent and treat SSI and should be aware of the emerging evidence in the fast-moving specialty of hernia surgery. Complex cases should be handled by surgeons and centers with expertise in treating such patients.

A very persistent chicken bone: two separate perforations from the same foreign object 2 months apart.

A 56-year-old man presented acutely with abdominal pain and raised inflammatory markers. Initial CT images demonstrated acute inflammation in the right upper quadrant surrounding a high-density linear structure. The appearance was of a chicken bone causing a contained small bowel perforation. This was managed conservatively with intravenous antibiotics and the patient was discharged 10 days later. The same patient returned to the hospital 2 months later, once again with an acute abdomen. CT imaging on this occasion showed distal migration of the chicken bone as well as free gas and fluid indicative of a new small bowel perforation. The patient underwent an emergency laparotomy, washout and small bowel resection. No foreign body was found at laparotomy or in the histopathology specimen. The postoperative course was complicated by an anastomotic leak. A further CT on that admission demonstrated that the chicken bone had migrated to the rectum!

A mesh masquerading as malignancy: a cancer misdiagnosed.

After a positive faecal occult blood test, a 60-year-old woman underwent a screening colonoscopy which identified a malignant-looking ulcer in the ascending colon. Biopsies from the lesion were inconclusive. A subsequent CT scan of the abdomen and pelvis commented on a polypoid lesion in the ascending colon. A colorectal cancer multidisciplinary team discussion concluded that a right hemicolectomy was indicated as the lesion was suspicious for malignancy. Intraoperatively, there was a firm ascending colon mass adherent to the abdominal wall, which was resected with clear margins. There were no other complications, and the patient was discharged without further issues. Histopathology from the retrieved specimen revealed a complete absence of malignancy, but rather, inflamed granulation tissue with 'reaction to foreign birefringent material'-likely to represent a mesh from an incisional hernia repair 9 years previously. The patient is currently recovering well without complication.

A Comparison of Two Monofilament Suture Materials for Repair of Partial Flexor Tendon Lacerations: A Controlled In-vitro Study.

BACKGROUND: Surgical repair is advocated for flexor tendon lacerations deeper than 70%. Repair can be undertaken with different suturing techniques and using different materials. Different materials used for tendon repair will have a different gliding resistance (GR) at the joint. Previous studies have compared strength of repair and gliding resistance for various braided suture materials and for 100% laceration of flexor tendons. We directly compare the GR of two monofilament sutures when used for a peripheral running suture repair of partially lacerated tendons. METHODS: Sixteen flexor tendons and A2 pulleys were harvested from Turkey feet. They were prepared, partially lacerated to 50% depth, and then repaired with a core suture (modified Kessler technique with 4-0 Ethibond) as well as an additional superficial running suture of either 6-0 Prolene or Nylon (half randomised to each). Gliding resistance was measured for all tendons before and after repair, at different flexion angles (40 and 60 degrees) and for different loads (2N and 4N). RESULTS: After surgical repair, gliding resistance was increased for all tendons (P < 0.01). The tendons repaired with Prolene had a higher mean gliding resistance than those repaired with Nylon (P = 0.02). Increased flexion angle and load amplified the gliding resistance (both P < 0.01). CONCLUSIONS: 6-0 Nylon was associated with a lower gliding resistance than 6-0 Prolene but the minor differences bare unknown clinical significance.

Bilateral, simultaneous pneumococcal septic arthritis of the knees: a normal immune system, an unknown source.

Pneumococcal septic arthritis is a rare clinical entity and is often associated with a systemic bacteraemia. A 60-year-old man was admitted with bilateral swollen, painful knees. He was feeling feverish with raised inflammatory markers. Joint aspiration yielded purulent fluid, which, when cultured, grew Streptococcus Pneumoniae bilaterally. The patient underwent repeated arthroscopic knee washouts and was treated with intravenous (IV) antibiotics. During his admission, various investigations and scans were undertaken to find an infective focus or signs of immunodeficiency; none were found. After 4 weeks of IV antibiotics and 4 knee washouts, the patient was discharged. We believe this is the only case documented of bilateral simultaneous pneumococcal septic arthritis of the knees in an immunocompetent patient with no extra-articular infective focus. This case exemplifies the importance of careful assessment of patients who present with bilateral swollen joints.

Incidental De Garengeot's hernia: A case report of dual pathology to remember.

INTRODUCTION: A De Garengeot's hernia is the very rare dual pathology of a vermiform appendix within a femoral hernia. PRESENTATION OF CASE: We discuss the rare case of a 62 year old female who presented as an emergency with a strangulated femoral hernia. Within the hernia sac a partly necrotic vermiform appendix was discovered. The patient successfully underwent an appendicectomy and repair of her femoral hernia. The post-operative period was uneventful, with no further issues at follow-up. DISCUSSION: Our case report displays the successful treatment of a De Garengeot's hernia as an emergency admission, with a shorter than average admission time, and no post-operative complications. CONCLUSION: This is a rare case of dual pathology, of which we believe there are few published cases.