Ch 84 Abdo wall recon and hernia Flashcards
hernias
- ring may be confined within a normal aperture in the abdominal wall true hernia) or (false hernias) as a result of trauma/incision
- congenital hernias, the sac is a mesothelial membrane (peritoneum) covering the contents,
- acute traumatic or incisional hernias, no sac is present
- Hernial contents without a mesothelial covering are at risk for developing adhesions
- classified by their location or by whether they are spontaneous or acquired.
What is an auto-penetrating hernia?
A traumatic abdominal wall hernia caused by a fractured rib penetrating through abdominal musculature
In the cranial, middle and caudal thirds of the abdomen, which aponeuroses are sitting superficial and deep to the rectus abdominis?
the external abdominal oblique is always superficial to the rectus
Cranial:
- External Oblique - Superficial
- Internal oblique - Both
- Transverse Abdominis - Deep
Middle
- External Oblique - Superficial
- Internal Oblique - Superficial
- Transverse Abdominus - Deep
Caudal
- All superficial
- external rectus sheath contains tendinous aponeuroses of the abdominal muscles that run superficial to the rectus abdominis muscle
- external rectus sheath has been shown to be the primary strength-holding layer throughout ventral midline closures
Where do the internal and external abdominal obliques and the transverse abdominis originate from?
External abdominal oblique
- Originates from 4/5th to 12th rib and from last rib and thoracodorsal fascia
- Runs in caudoventral direction
Internal Obdominal oblique
- Originates from thoracolumbar fascia caudal to last rib and from tuber coxae
- Runs cranioventral
Transverse Abdominis
- Lumbar portion arising from the transverse processes of the lumbar vertebrae and thoracolumbar fascia
- Costal portion - Arising from medial sides of 12th and 13th rib as well as 8th-11th costal cartilages
- Runs in dorsoventral direction
Location of Abdominal Hernias
trauma
* Paracostal hernia;
* dorsal lateral hernia;
* pre-pubic ligament rupture
* femoral hernia;
congenital
* umbilical hernia;
* ventral hernia (subxiphoid)
* scrotal hernia
* inguinal hernia;
What are substernal midline defects often associated with?
Congenital peritoneal pericardial diaphragmatic hernia
PPDH often assoc with incompletely fused caudal sternebrae
Pathophysiology of Abdominal Hernias
- Hernias can result from genetically impaired collagen, wound healing deficiencies; traumatic injury; failed closures
- overall success of repair rarely depends on the repair itself but sequelae to organ herniation or trauma that impaired normal body function > loss of domain, incarceration or obstruction, or strangulation, traumatized organs
acquired hernias
- mechanical strain on load-bearing tissues induces secondary changes in fibroblast > results in abnormal collagen and fascial weakness.
Space-Occupying Effects
“Loss of domain”
- abdominal wall has become accustomed to a relatively small intraabdominal volume because of organ displacement
Forcing the herniated contents can result in:
1. excessive tension on the repair (risk for recurrence)
2. acute pulmonary complications, (restriction of diaphragm function)
3. poor organ perfusion (abdominal compartment syndrome)
List methods of explansion used in human surgery for loss of domain
Progressive pneumoperitoneum
Silastic expanders
Staged reduction
Prosthetic material
Incarceration
- incarcerated organs are irreducible and can become lethal, strangulated obstructions within hours
- incarcerated obstruction depend on contents of the hernia and size of the defect > inelastic hernial rings, such as scrotal or femoral hernias, are at high risk
- intestine, uterus, or bladder
- SI: risk is greatest when the hernial ring approximates the size of the bowel.
- urinary bladder: perineal, ventral, inguinal, and traumatic pubic hernias
- decompression and diversion of urine flow before sx (cysto, catheter, cystostomy tube)
Strangulation
- implies contents are incarcerated and undergoing devitalization from arrested circulation.
- Impaired circulation> venous or arterial occlusion or a combination
- Early venous obstruction > reversible organ engorgement
- subsequent arterial stagnation occurs due to interstitial pressure at capillary beds > causes rapid organ necrosis (wall compromise or rupture)
mechanisms:
- constriction of the blood supply at the hernial ring
- torsion of the vascular pedicle
- Traumatic > adhesions trap organs within the hernia, and contraction during wound healing eventually constricts the hernia ring
- complications and death is 50% higher in humans with incarcerated or strangulated hernias
How can intestinal strangulation lead to rapid systemic illness?
- Bacterial transmigration (through the compromised tissue, rupture may cause toxaemia and septicaemia)
- Vasoactive substances release (arachidonic acid metabolites, cytokines, leucotrienes, kinins) from tissue and blood cell autolysis
- Redistribution of fluids and severe cardiopulmonary effects
- surgical reduction of strangulated hernias may causerapid release of vasoactive substances into the circulation
Principles of Abdominal Hernia Repair
indications:
(1) the hernia is symptomatic (abdominal discomfort, organ obstruction),
(2) the hernia results in significant protrusion that affects the animal’s quality of life or the owner
(3) the hernia poses a significant risk for hollow organ obstruction
Goals of sx
(1) ensure the viability of entrapped hernia contents;
(2) release and return contents into their normal location within the abdominal cavity;
(3) obliterate redundant hernia sac tissue;
(4) provide a tension-free and, if possible, secure primary closure of the defect using strong, healthy surrounding tissue.
Ventral Abdominal Hernias
Anatomy, Etiology, and Pathogenesis
- embryo the abdominal wall is formed by migration of cephalic, caudal, and lateral folds.
- The umbilical aperture, passageway for cord (umbilical blood vessels, small vitelline duct, and stalk of the allantois), remains after normal migration and fusion of these folds
- falciform ligament and middle umbilical ligament of the bladderare attached to the internal aspect of the umbilicus.
- During embryologic development the umbilical ring allows herniation of the midgut into the coelom of the umbilical cord, where it has more room to grow.
- Failure of fusion or delayed fusion of the lateral folds result in a congenital umbilical hernia
- Most umbilical hernias are inherited and are probably the result of a polygenic
- concomitant incomplete caudal sternal fusion or diaphragmatic hernias
- falciform ligament (the remnant of the umbilical vein)
- middle umbilical ligament of the bladder (the remnant of the urachus)
What is the embryological cause of ventral abdominal wall hernias?
Failure of fusion or delayed fusion of the lateral folds (primarily the rectus abdominis)
What disorders have been associated with congenital ventral abdominal hernias?
search for other congenital defects
Fucosidosis
Ectodermal dysplasia
Cryptorchidism
What initially protects and omphalocoele?
Omphaloceles are large midline umbilical and skin defects that permit abdominal organs to protrude from the body.
- A thin transparent membrane of amniotic tissue
What is gastroschisis?
A congenital ventral abdominal hernia, very similar in appearance to an omphalocoele but it is paramedian
What breeds are predisposed to umbilical hernias?
Airedale terriers
Basenjis
Pekingese
Pointers
Weimeraners
treatment
- large umbilical or supraumbilical abdominal wall defects, especially when incomplete caudal sternal fusion is present, are specifically examined for other congenital diaphragmatic or cardiac defects before correction.
- suspicious of entrapped viscera and obstruction when animals present with acute gastrointestinal signs (vomiting, anorexia) and a firm, irreducible, painful umbilical mass
- further examined by radiography, ultrasonography
sx
- small (<2 to 3 mm) hernias are treated conservatively because spontaneous closure has been reported as late as 6 months of age
- neutered because of genetic predisposition
- approximate the size of intestine (one-finger size in a small- to medium-sized dog) sx is indicated
- sac is dissected free
- If fat alone > neck is ligated, sac and contents are excised.
- Small sacs can be inverted into the abdomen.
- Marginal debridement of wound edges or rectus sheath is generally recommended
- Umbilical hernias containing abdominal organs may require more extensive surgery.
- incarcerated hernias without strangulation, the hernial sac is dissected free, The hernial ring is enlarged to release the contents into the abdomen, sac is excised, and the hernial ring is debrided,
- Most umbilical hernias can be primarily closed
- Fascial releasing incisions can be made to reduce tension on the primary suture line (at least 2 cm away from the defect and through the external rectus fascia only) fascia is elevated and shifted toward the midline
-
Caudal Abdominal Hernias
- inguinal
- scrotal
- femoral
- inguinal region are categorized as direct or indirect
- Direct hernias are usually large, and most do not cause incarceration or strangulation
- scrotal hernia—an indirect inguinal hernia
- inguinal hernias are more common in female dogs
- more unilateral inguinal hernias occur on the left side than on the right
- Large hernias may contain a gravid uterus (hysterocele), bladder, or jejunum
- vomiting for 2 to 6 days before admission predicted a strangulated small intestine.
- risk for strangulated intestine in dogs with long-standing inguinal hernia is less than 5%.
What are the 2 broad classifications of inguinal hernias?
- Indirect - hernia contents enters the cavity of the vaginal process
- Direct - Hernia contents pass through the inguinal ring adjacent to the vaginal process (less common)
Are inguinal hernials common?
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
Describe the anatomical boundaries of the inguinal rings?
- 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
What structures pass throught the inguinal canal?
- 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
Which breeds have been shown to have heritable inguinal hernias?
Golder Retrievers
Cocker Spaniels
Dachshunds
List factors which may predispose an animal to an inguinal hernia (4)
pathogenesis
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
List some differentials for an inguinal hernia (8)
- Soft tissue maass
- Mammary tumour or cyst
- Lipoma
- Enlarged LN
- Abscess
- Haematoma
- Testicular torsion/abscee/neoplasia
- Orchitis
diagnosis
- 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
surgery - inguinal hernia
- 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.
List closure options for an inguinal hernial which cannot be primarily closed
- Polypropylene mesh onlay
- Sartorius muscle flap
Why is castration recommended after a scrotal hernia?
- Reduce recurrence
- Prevent offspring (may be heritable)
- Increased risk of testicular neoplasia
- Testicular necrosis
surgery - scrotal hernia
- 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
Complications, Aftercare, and Prognosis
- 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
Femoral Hernias
Where is the femoral canal located in relation to the inguinal canal?
Lateral to the inguinal ligament (caudolateral to inguinal canal)
Anatomy and Pathogenesis
- 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
What are the two lacunae of the femoral canal?
- 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.
Where does herniation tend to occur in femoral hernias?
In the femoral canal; a potential space caudomedial to the femoral vessels
Broadly speaking, how do you correct femoral hernias?
Intra-abdominal closure of the hernia sac
Extra-abdominal reconstruction of the hernia ring
surgery- femoral hernia
- 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
Traumatic Hernia
Anatomy and Pathogenesis
- 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
diagnosis
- 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)
Decision making and timing for surgical repair of traumatic abdominal hernia
- 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
The method of closure for traumatic hernia
- 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)
List options for repair of a cranial pubic ligament avusion if primary repair is not possible
Hole into pubis
Rectus abdominis flap
Sartorius flap
prognosis depends on accompanying injuries and is rarely associated with the herniorrhaphy itself
What are the 2 broad causes of incisional hernia?
- Excessive force on incision
- Poor holding strength of the wound
Incisional Hernias pathogenesis
- 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
risk factors
risk factors
- increased intraabdominal pressure from pain,
- entrapment of fat between edges,
- inappropriate suture material use,
- infection,
- chronic steroid treatment
- poor postoperative care
What is the suture-to-wound length ratio fo abdominal wall closure?
What are the recommended suture bites?
4:1 ratio
Equates to 5-7mm fascial bites with 3-4mm of travel
What is the most consistent sign of impending abdominal wall dehiscense?
Swelling and serosanguinous drainage from the incision
usually develop within the first 3 to 5 days after surgery
omentum herniated through a small defect may cause persistent wound swelling or fluid accumulation and may be difficult to diagnose even with imaging; thus wound exploration may ultimately be required for diagnosis and repair.
Treatment of Incisional Hernia
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
Is debridement recommended for treatment of acute incisional hernia?
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
Treatment of Incisional Evisceration
- 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
Reconstruction of Large Abdominal Wall Defects
Perform preoperative Patient Assessment
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.
List some autologous repair methods for large abdominal wall defects (6)
- 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)
Cranial sartorius muscle flap (branch of femoral artery and vein at proximal third)
- 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
External abdominal Oblique muscle flap (cranial branch of cranal abdominal artery supplies middle zone of lateral abdominal wall)
- myofascial island flap based on the lumbar component
- island flap can be used successfully for treatment of ventral, cranial to mid–abdominal wall defects
Rectus Abdominis Flap
- 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
List some nonautogenous repair methods for large abdominal wall defects
- Synthetic mesh (polypropylene - inert, woven, monofilament, porous)
- Tissue grafts or bioprosthetic mesh (porcine SIS)
Tissue Grafts or Bioprosthetic Mesh
- 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
Synthetic Mesh
- 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.
What are the three methods of mesh placement?
Which is most commonly used?
- Overlay
- Interposition
- 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)
underlay tehcnique
- 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.
Complications: peri-op, early and late
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
goals
- 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
Dog bite wounds in cats:
a retrospective study of 72 cases
Sigal Klainbart 2022
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
A quilting subcutaneous suture pattern to reduce seroma
formation and pain 24 hours after midline celiotomy in dogs:
A randomized controlled trial
Blake M. Travis
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.
A novel internal abdominal oblique muscle flap to close a major abdominal wall defect
Hall 2021
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
Retrospective Study on Clinical Features and
Treatment Outcomes of Nontraumatic Inguinal
Hernias in 41 Dogs
Teruo Itoh,
JAAHA
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.
TRaumaTic abdominal wall
RupTuRe in caTs
Decision-making and
recommended repair techniques
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.
