Ch 84 Abdo wall recon and hernia Flashcards

Question

Are inguinal hernials common?

Answer 1

Congenital is rare Acquired is common. - Congenital more often in male dogs than in females (delayed inguinal ring narrowing from late testicular descent) - Acquired most often involve middle-aged, intact bitches

Answer 2

- Internal inguinal ring: Bound by rectus abdominis, inguinal ligament and internal abdominal oblique - External inguinal ring: Longitudinal slit in the aponeurosis of the external abdominal oblique

Answer 3

- vaginal process (spermatic cord in males,round ligament in females) - Genital branch of genitofemoral nerve, artery and vein - Cremaster muscle passes through external ring - Pass through the caudomedial aspect

Answer 4

Golder Retrievers Cocker Spaniels Dachshunds

Answer 5

Enlargement of the entrance to the vaginal process, which remains open in domestic animals = most important cause of inguinal hernias > may depend on a neuromuscular reflex + normal anatomic barrier at the inguinal rings * genetics (inheritence) but only in a few breeeds * Bitches have a shorter and wider inguinal canal * Most commonly occur during oestrus in intact bitches, suggesting oestrogen has a close association (changing strength and character of connective tissue) * Associated with inguinal and perineal hernias in male dogs (siilar but unknown underlying cause) * Obesity (accumulation of fat around the round ligament) | three major areas: anatomic, hormonal, and metabolic

Answer 6

* Soft tissue maass * Mammary tumour or cyst * Lipoma * Enlarged LN * Abscess * Haematoma * Testicular torsion/abscee/neoplasia * Orchitis

Answer 7

- confirmed by manual reduction of hernia contents and palpation of the hernial ring - palpation of both inguinal canals is recommended because inguinal hernias can be bilateral - scrotal: cord-like structure extending from the inguinal region - Sharp pain is commonly exhibited with palpation when a strangulated scrotal hernia is present - Incarcerated hernias present more of a diagnostic challenge because palpation may not yield a definitive diagnosis. - nature of herniated contents can be confirmed with plain or contrast radiography, ultrasonography, or computed tomography (CT). - possible contents: free fluid, omentum, fat, ovary, uterus, small intestine, colon, bladder, or spleen

Answer 8

- Strangulated hernias require emergency surgery; nonstrangulated scrotal hernias are also repaired soon after diagnosis because the risk for strangulation - Uncomplicated approached over the inguinal ring. - complicated hernias (incarcerated or strangulated contents, or concurrent serious intraabdominal trauma), the approach ventral abdominal midline - If the hernia is not easily reducible, the sac is opened, and the canal is enlarged - neck of the hernial sac is ligated as close to the internal inguinal ring - external canal closed with prolonged absorbable or nonabsorbable sutures. - gap is left caudally (pudendal and genitofemoral vessels, nerve +/- spermatic cord) - A single midline incision permits simultaneous hernia repair of uncomplicated bilateral hernias and access to the abdominal cavity for complicated hernias.

Answer 9

- Polypropylene mesh onlay - Sartorius muscle flap

Answer 10

* Reduce recurrence * Prevent offspring (may be heritable) * Increased risk of testicular neoplasia * Testicular necrosis

Answer 11

- If the testicle preserved: enlarged neck of the hernia sac (parietal vaginal tunic) is reduced by a transfixing ligature or horizontal mattress sutures > placed close to internal inguinal ring - external inguinal ring > caudal aspect open for vessels - Strangulated viscera within scrotal hernias are approached by a ventral midline incision. - Repair of the scrotal hernia is performed extraabdominally (ideally en bloch resection of maserated contents) - Bilateral castration is currently recommended

Answer 12

- most common complication: hematoma or seroma formation - scrotal dermatitis and hematomas (avoided by scrotal ablation) - Exercise is strictly limited until suture removal. - Prognosis for uncomplicated repair of inguinal hernia is good to excellent - complications was 17%, and the mortality rate was 3%. Incisional infection, peritonitis and sepsis, and hernia recurrence - Prognosis is guarded to poor with strangulated hernias

Answer 13

Lateral to the inguinal ligament (caudolateral to inguinal canal)

Answer 14

- The femoral canal is in the caudal abdominal wall just lateral to the inguinal ligament. - Herniation likely occurs in a potential space caudomedial to the femoral vessels known as the femoral canal - Factors involved in the development of femoral hernias in small animals are unclear - Iatrogenic > transection of the origin of the pectineus muscle - appearance similar to inguinal hernias. - generally develops on the medial aspect of the thigh - If reduction is not possible, differentiation from other inguinal masses may be difficult > advanced imaging may be required

Answer 15

- Muscular lacunae - Femoral nerve within iliopsoas muscle - Vascular lacunae - Craniolateral to muscular lacunae and contains femoral artery and vein and saphenous nerve - Iliopectineal arch (iliac and transverse fascia) seperated the lacunae.

Answer 16

In the femoral canal; a potential space caudomedial to the femoral vessels

Answer 17

Intra-abdominal closure of the hernia sac Extra-abdominal reconstruction of the hernia ring

Answer 18

- frequently mistaken for inguinal hernias and may have concurrent prepubic tendon rupture - uncomplicated femoral hernia repair is made parallel to the inguinal ligament - femoral canal is usually closed by placing sutures between the inguinal ligament and pectineal fascia - avoid vital neurovascular structures in the area. - complicated: ventral abdominal midline, Closure of the hernia sac is performed intraabdominally by inverting and ligating the sac after the affected organs are evaluated - extraabdominal reconstruction of the hernia ring then performed - Some degree of pelvic limb swelling is usually present after surgery > if persistant may indicate obstruction of lymphatic or venous drainage at the femoral ring

Answer 19

- lack a complete serosa-lined hernial sac, their contents may be more prone to adhesion to extraabdominal structures and incarceration. - most common areas by blunt trauma are inguinal or prepubic area (making up 15% to 45% of traumatic abdominal hernias) and the paracostal regions - Blunt trauma with abdominal muscles contracted and the glottis open (limits an increase in intraabdominal pressure) - may result in traction- or avulsion-type injury to tissues with minimal elasticity (e.g., muscle attachments to bone) - Rupture of the cranial pubic ligament is often associated with concurrent inguinal ligament damage - sudden increase in intraabdominal pressure may result in rupture of the weakest portion of the abdominal wall. - Paracostal hernias develop when the origin of the external oblique abdominal and transverse abdominal muscles separate from their rib or costal cartilage origin - frequently occur with diaphragmatic rupture - 75% of traumatic abdominal hernias have other significant injuries; most are orthopedic and usually involve the pelvis

Answer 20

- The contents of the hernia may remain in the abdomen - Progressive enlargement may indicate obstruction of a hollow viscus - most obvious clinical signs associated with out traumas (i.e shock, fracture) dx - obvious is reducible/palpable - Diagnosis of irreducible or ill-defined traumatic abdominal hernias is more challenging - check for all trauma's - Free intraabdominal gas or a penetrating wound = indication for emergency surgery - rads: discontinuous abdominal wall (loss of abdominal strip) and absence of abdominal organ from its normal location +/- Contrast studies - ultrasonography, CT, (MRI)

Answer 21

- stabilise, cover open wounds - Reducible large hernias can be externally supported with abdominal bandages and surgery delayed - repair as soon as a patient is stable - if delayed too long, wound contraction and adhesion formation may complicate repair - Emergency surgery > do not stabilize or that deteriorate, Penetrating wouds, herniated organs become progressively more turgid and dilated - Acute hernias > approach midline - Debridement is aimed at removing devascularized fat and muscle tissue - Dog bites produce severe tissue damage > abdominal wounds repaired with local vascularized tissues, if possible. - Subcutaneous tissues and skin > open wound mgmt

Answer 22

- blunt abdominal trauma generally have minimal abdominal wall loss and can be successfully closed by apposing the hernial ring - acute/chromic > Closure may require reconstruction with a local tissue flap or synthetic underlay mesh. - Sutures should appose the tissues, not crush them, and incorporate generous bites of strong fascia, ligament, or bone - Ideally, muscle layers are individually closed - (polyglyconate or polydioxanone) or nonabsorbable sutures in a tension-dispersing pattern (e.g., cruciate or horizontal or vertical mattress) - Sutures are preplaced, - Closure of the defect is facilitated by proper positioning of the patient - Shredded avulsed cranial pubic ligaments or other muscle fascia may be augmented with a mesh cuff or double-layer mesh technique - paracostal hernia: soft tissue attachment to adjacent bone are closed by passing sutures through bone tunnels or bone anchors or around ribs (check for occult diaphragmatic hernia)

Answer 23

Hole into pubis Rectus abdominis flap Sartorius flap

Answer 24

* Excessive force on incision * Poor holding strength of the wound

Answer 25

- reported in 1% of cats and 0.08% of dog 1. **technical error** 2. **Excessive Forces on the Incision** (muscle tension or excessive intraabdominal pressure - obesity, ileus, coughing) 3. **Poor Holding Strength of the Wound** (choice of suture, knott security, suture pattern doesn't matter > strength-holding layer external rectus fascia most important) Interrupted suture patterns are preferred over continuous patterns if wound edges have questionable viability or strength 4 : 1 suture-to-wound length ratio

Answer 26

risk factors - increased intraabdominal pressure from pain, - entrapment of fat between edges, - inappropriate suture material use, - infection, - chronic steroid treatment - poor postoperative care

Answer 27

4:1 ratio Equates to 5-7mm fascial bites with 3-4mm of travel

Answer 28

Swelling and serosanguinous drainage from the incision | usually develop within the first 3 to 5 days after surgery

Answer 29

ACUTE - repaired without delay because prognosis may change dramatically when evisceration occurs. - causal factors should be identified - If technical failure is suspected (knot, suture, or tissue failure), the entire wound is reopened and repaired. CHRONIC - Pain, discoloration, incarceration, or a rapid increase in hernia size + Palpable adhesions = indications for early surgical intervention - simple imbrication without excision of the scar edge to healthy fascial margins usually results in recurrence of the hernia - muscle edges may have retracted > producing a functional loss of abdominal wall > excessive tension - loss of domain > result in acute pulmonary dysfunction from restriction of diaphragm movement, and pressure on internal organs > abdominal compartment syndrome. - prosthetic materials may be required to close chronic hernia

Answer 30

Not unless fascial edges are devitalised, infected or unidentifiable Contraindicated as it caused excessive and unnecessary tissue trauma and set the wound back to its substrate phase, delaying the onset of rapid fascial strength gain

Answer 31

- early aggressive supportive therapy and emergency surgery - Appropriate fluid, blood product, and antibiotic therapy are critical to stabilize the patient. - explore > resected or repaired. - Specimens for C&S. - copiously lavaged - Primary repair is appropriate for acute herniation +/- open wound mgmt for skin - severely contaminated or dirty wounds may be tx by open peritoneal drainage - evisceration, prompt and aggressive medical and surgical intervention can provide a favorable outcome - spesis ? gaurded prognosis

Answer 32

The goals: - restore the integrity of the myofascial layer of the abdominal wall, - provide dynamic support, - protect the underlying abdominal contents, - provide a durable cutaneous cover Heavily contaminated: - treated with open peritoneal drainage - negative-pressure wound therapy system; - lavage, - continuous suction drain placement Autologous Versus Nonautologous Options - own tissue (autologous) is preferable to nonautologous - potential to contribute additional circulation to areas that are ischemic because of trauma, poor collateral circulation, or radiation damage - more resistant to infection when used in contaminated environments, compared with mesh reconstruction.

Answer 33

* Vacuum assisted closure * Separation of anatomic components (fascial releasing incision and adjacent tissue transfer) * Abdominal wall partitioning (multiple parasagittal releasing incisions in staggered pattern) * Cranial sartorius muscle flap (branch of femoral artery and vein at proximal third) * External abdominal Oblique muscle flap (cranial branch of cranal abdominal artery supplies middle zone of lateral abdominal wall) * Rectus abdominis muscle flap (cranial and caudal epigastric vessels)

Answer 34

- approximate areas covered: - caudal 30% of the abdomen - 80% of the length between the pubis and ribs on the ipsilateral side if the flap is positioned parallel to midline - good option for augmenting repair of prepubic tendon rupture

Answer 35

- myofascial island flap based on the lumbar component - island flap can be used successfully for treatment of ventral, cranial to mid–abdominal wall defects

Answer 36

- two vascular pedicles, The principal is derived from the caudal epigastric artery. - more substantial muscle thickness and strength compared to the sartorius muscle flap. - used successfully to repair prepubic tendon ruptures in eight dogs

Answer 37

- Synthetic mesh (polypropylene - inert, woven, monofilament, porous) - Tissue grafts or bioprosthetic mesh (porcine SIS)

Answer 38

- small intestinal submucosa (SIS), dermis, or pericardium. - not cause a chronic foreign body response - when synthetic mesh is contraindicated > dirty, grossly contaminated, or infected wounds. - graft acts as a scaffold to induce in situ normal tissue regeneration > replacement of the graft material by the host - failed to demonstrate consistent evidence of biologic mesh remodeling - Used successfully experimentally and clinically to repair perineal hernias IN DOGS

Answer 39

- allows a tension-free solution - readily available, strong, biologically inert, and easy tailored to the appropriate size and shape - polypropylene mesh (woven > infiltrated with fibrous tissue) - new macroporous mesh (Restorelle; Coloplast) > greater type I collagen content in dogs experimentally - dramatically reduced hernia recurrence rates in humans - larger, clean abdominal wall defects - require adequate skin and subcutaneous coverage - Failure usually the result of tension or infection >most implant associated with varying risk for sinus formation and chronic infection - intraabdominal structures protected from prosthetic by interposition of omentum - HUMANS: Composite meshes (a combination of absorbable and nonabsorbable materials) acute strength during the first few weeks, absorbable replaced by collagen, a low-weight, nonabsorbable material remains, ensuring permanent strength with low patient morbidity.

Answer 40

1. Overlay 2. Interposition 3. Underlay Underlay most often used, lowest rate of reherniation and wound complications - Better distribution of tension (pascal principle > pressure applied to the mesh at one point is transmitted equally throughout the entire area due to the underlying fluid-filled space) - Superior formation of post-op connective tissue - Sliding myofascial flaps or adjacent adipodermal flaps placed over and underlay mash provide another later of mechanical buttress and barrier from infection - Underlying omental patch to minimise adhesions (and enterocutaneous fistulas)

Answer 41

- weakest point of a mesh repair is the interface between the native fascia and the synthetic material (why inlay has highest recurrence) - Anchoring the mesh to stable fixation points in the abdominal wall is a key element of a successful repair. - mesh is cut 2 cm larger than the defect - Healthy omentum is mobilized, folded on itself to make multiple layers - mesh edges are folded inward and upward (away from viscera) to make a double-thickness, reinforced edge. - Monofilament nonabsorbable sutures are preplaced - bite (at least 1 to 2 cm away from the edge) through muscle, double-mesh and omentum. - implanted ePTFE mesh material that becomes infected usually must be completely removed to successfully control the infection.

Answer 42

peri-op * Anesthesia complications * Hemorrhage * Visceral injury * Strangulated hernia * Gross contamination at the surgical site * Inability to close the abdominal wall without tension * “Loss of domain” * Poor tissue strength at hernia margins Early post-op (<2wks) * Seroma * Hematoma * Dermatitis * Infection * Wound dehiscence and evisceration * Pain late post-op * Skin sinus * Hernia recurrence

Answer 43

- Large case series of abdominal hernias repaired with mesh have not been reported in the small-animal literature - peri-op compliations often due to poor surgical technique - Surgical goals: halsteads principles - Conditions causing increased intraabdominal pressure, such as vomiting, straining to urinate or defecate, and coughing, should be resolved

Answer 44

significant association between the number of injured body areas and survival, and between severity of injury and surviva Fifty percent of cats were treated conservatively, 32% by local surgical debridement and 18% of cats required an exploratory procedure. Cats undergoing more aggressive treatments were significantly less likely to survive (P = 0.029). Fifty-seven cats (79%) survived to discharge negative predictors of survival: - multiple body area injuries, - penetrating injuries, - radiographic evidence of vertebral body fractures and body wall abnormalities, - hypoproteinaemia

Answer 45

Four hundred thirty-two dogs the incidence of incisional seroma was lower in the quilting group (odds ratio50.30, 95% CI50.13-0.67, P5.004). Pain assessed 24 hours postoperatively was lower in the quilting group (P5.03). The incidence of SSI did not differ between groups. Conclusion: Tacking the subcutaneous tissues to the deep fascia is indicated to reduce seroma during celiotomy closure.

Answer 46

En bloc resection of a chondrosarcoma and biopsy scar centred on the 13th rib was performed to include full thickness thoracic wall (12th rib, extending caudally) and lateral abdominal wall (including the vascular pedicle of the external abdominal oblique muscle). The diaphragm was advanced to close the thorax. A flap using the caudal internal abdominal oblique muscle with the base dorsally was elevated and rotated 90° to fill the dorsal defect. The ventral defect was closed using the composite ventral abdominal muscles

Answer 47

NTIHs are more likely to occur in middle- to older-aged, female, small-breed dogs, and miniature dachshunds may be predisposed. The most frequently protruded hollow organ in our study was the uterus, which tends to protrude on the left side, and intestinal herniation may occur concurrently. Physiological or pathological enlargement of the uterus associated with aging and sex hormones appears to increase the risk of uterine herniation, but the long-term prognosis of herniorrhaphy combined with OVH is excellent.

Answer 48

there is little evidence in the literature to inform timing of surgery.13 Based on studies on canine and feline diaphragmatic hernias14 and in the human medicine field, the current advice for timing of surgery is to operate when the patient has beenstabilised muscle fascia takes approximately 3 weeks to reach 20% of its original strength after injury and up to a year to regain 80% of its original strength If the muscle is friable, a locking loop suture pattern or individual sutures reinforced with buttress material, such as polytetra fluoroethylene (PFTE), may be required to reduce the risk of pull-through prepubic area (no tendon in cats) - two crura of the superficial inguinal ring are firmly attached to the cranial border of the pubis + Attachments of the aponeurosis of the external abdominal oblique - Drilling holes through the pubic brim important to inspect the crura of the superficial inguinal ring as well as the aponeurosis of the external abdominal muscle Paracostal ruptures (Figure 6) also require a particular repair technique. They are more common in cats than dogs and involve the origin of the external abdominal oblique and the transversus abdominis muscles, and the insertion of the internal oblique muscle ribs as anchors with non-absorbable sutures such as polypropylene. As the site is in constant movement due to breathing, recurrence of herniation is common The most frequent locations in cats for traumatic abdominal wall rupture are prepubic, paracostal, inguinal and dorsolateral. < Traumatic abdominal wall rupture is often associated with concomitant injuries. < A thorough examination and assessment of injuries is key and may require advanced imaging. < Stabilisation, when required, should always be the first priority. < A complete assessment of the abdominal cavity should be made during surgery. < Preplacement of sutures in an interrupted pattern is the key to a successful repair. < The surgeon should be prepared to implement specific repair techniques, dependent on the extent and location of the wound.