Abdominal wall

Question 1

Definition of hernia

Answer 1

An abnormal protrusion of a cavity’s contents through a weakness in the wall of the cavity.
75% hernias are inguinal – 2/3 indirect, 1/3 direct
▪ M:F 25:1
• Men – indirect:direct 2:1
o Femoral hernia M:F 1:10

Question 2

Lumbar hernia

Answer 2

• Superior triangle (Grynfeltt) (QIT)
o Quadratus lumborum
o Internal oblique
o Twelfth rib
o Transversalis fascia and transversus abdominis muscle (floor)

• Inferior triangle (Petit) (LIE)
o Latissimus dorsi
o Iliac crest
o External oblique
o Internal oblique (floor)

Question 3

Pathophysiology of inguinal hernia

Answer 3

Aetiology
o Congenital tissue quality
▪ CT disorders (Ehlers danlos)
o Increased intraabdominal pressure ▪ Coughing, straining, heavy lifting, ascites
o Acquired tissue quality
▪ Smoking, malnutrition, steroids, deficiencies

• Pathology
o Sac is anteromedial within cord in indirect hernia

Question 4

Contraindications to laparoscopic inguinal hernia

Answer 4

▪ Previous preperitoneal pelvic surgery – previous TEP, radical prostatectomy pfannenstiel
▪ Incarcerated hernia
▪ Large inguinoscrotal hernia
▪ Ascites, portal hypertension
▪ Pregnancy
▪ Coagulopathy
▪ Severe coronary artery disease (don’t tolerate head down)

Question 5

Management of post inguinal hernia pain.

Answer 5

o 10%
o Pain persisting >3 months
o Management strategies
▪ Anti-inflammatories
▪ Analgesics
▪ Local anaesthetic nerve blocks
▪ If nerve entrapment – repeat exploration and neurectomy/mesh removal/tack removal

Question 6

Complications of inguinal hernia repair

Answer 6

o Infection – 1%
o Seroma/haematoma
o Urinary retention
o Loss of sensation – 100%
o Persistent pain (10%)
o Recurrence (2%), no mesh 10-30%
o Ischaemic orchitis/ testicular atrophy – rare
o Hydrocele – rare

Question 7

Ectopic vs undescended testis

Answer 7

Undescended testis
- Interrupted descent during normal development
▪ Usually located in path of descent ie inguinal canal

Ectopic testis
o Aberrant path of descent
▪ Perineal
▪ Femoral canal
▪ Suprapubic region

Prognosis/ natural history
- Infertility Starts at age 2
- Increased risk of malignancy (30x) -> Not alleviated by orchidopexy; increased risk of malignancy in contralateral testis

Management
- Unilateral palpable testis in inguinal canal -> Subdartos pouch orchidopexy at age 6 months to 1 year

Question 8

Omphalocele vs gastroschisis

Answer 8

Omphalocele
▪ Abdominal viscera herniate into umbilical cord
• Failure of midgut to return to abdomen after week 10
▪ 1/5000 births
▪ Usually related to chromosomal/cardiac/renal/limb/facial abn)
• Beckwith Wiedemann syndrome, trisome 13/15/18/21, ,exstrophy of bladder or cloaca, pentalogy of cantrell

Gastroschisis
▪ Abdominal wall defect to right side of umbilicus (site of obliterated right umbilical vein)
• Most of intestinal tract will protrude
• Isolated anomaly

Question 9

Factors predisposing patients to incisional hernia.

Answer 9

Systemic factors
▪ Wound healing
• Age
• Malnutrition – can check albumin
• Diabetes
• Smoking – especially 4 weeks pre and post op
• Steroids/ chemotherapy
• Anaemia/shock/sepsis
• Connective tissue disorders

▪ Raised intraabdominal pressure
• Obesity – BMI >50 = 100% recurrence
• Ascites
• Pregnancy
• COPD/chronic coughing
• Chronic constipation

Local factors
▪ Wound
• Infection
• Seroma
• Haematoma
• Contaminated wound

▪ Technical
• Excessive tension
• Too close to fascial edge
• Excessive suture interval
• Suture failure
• Emergency surgery

Question 10

Stages of wound healing

Answer 10

1 – Coagulation

2 - inflammatory (days 1-4)
▪ Necrotic debris digested
▪ Acute inflammation

3 – proliferation (days 5-20)
▪ Fibroblasts → angiogenesis, collagen, epithelialisation
▪ Requires adequate blood supply
▪ 15-30% original strength

4 – remodelling (up to 12 months)
▪ Collagen production and breakdown and reorganised along lines of tension
▪ 80% of original strength

Question 11

Principles of abdo closure

Answer 11

Principles
▪ Mass closure
▪ Simple running technique
▪ Absorbable monofilament
▪ Suture length to wound length ratio at least 4:1
▪ 1cm depth x 1cm width

o STITCH trial
▪ Advocates small bites technique (0.5cm bites) superior to traditional closure

Question 12

Techniques of component separation

Answer 12

Myofascial release
▪ Allows medial advancement of muscle layers to allow restoration of midline without tension
▪ Preservation of neurovascular structures

Posterior component separation
▪ Incise posterior rectus sheath 1cm medial to linea semilunaris
• Internal oblique and transversus abdominis are opened to allow access to preperitoneal space which can be extended around to retroperitoneum and psoas muscle

Anterior component separation
▪ Raise flap over external oblique
• Incise external oblique 3cm lateral to linea semilunaris
• Separate external oblique from internal oblique to allow advancement of rectus
▪ When applied bilaterally 20cm of length can be created

Question 13

Strategies for large hernias

Answer 13

o Optimisation of risk factors
▪ Cease smoking (check urine cotinine)
▪ Weight loss (bariatric surgery)
▪ Control diabetes (HbA1c)
▪ Control BPH, cough, COPD

o Prevention of complications ‘
▪ Drains ?
▪ HDU post op
▪ Early mobility, physio
▪ DVT prophylaxis

o Improving likelihood of closure
▪ Botox 300 units
▪ Anterior or posterior component separation (not both)
• Anterior helps closure
• Posterior allows retrorectus to go further around
▪ Total colectomy, perinephric fat debulking

Question 14

Dealing with loss of domain

Answer 14

o Abdominal contents no longer reside within abdomen (50% reside outside abdominal cavity)

o Rigidity of abdominal wall is compromised and muscles become retracted

o Effects
▪ Respiratory compromise (paradoxical abdominal motion)
▪ Bowel oedema, splanchnic venous system stasis
▪ Urinary retention, constipation

o During repair, need to consider: ▪ Increased abdominal pressure / abdominal compartment syndrome when organs replaced
▪ Can result in respiratory and circulatory disturbance

o Advanced techniques may be required ▪ Component separation
▪ Preoperative pneumoperitoneum
▪ Preoperative tissue expanders

Question 15

Types of mesh

Answer 15

Synthetic
▪ Desirable characteristics
• Inert, resistant to mechanical stress, maintains compliance, sterilisable, non carcinogenic, hypoallergenic, minimal inflammatory response
• Micropores >10 um → allowing penetration by immune cells
• Macropores >1mm → fibroblast/collagen infiltration allowing formation of scar net rather than scar plate

▪ Features
• Weight of mesh
o Light weight <50g/m2, heavy weight >80g/m2
o Lightweight mesh usually has absorbable component to allow better handling initially
• Pore size
• Hydrophilic/hydrophobic
• Antiadhesive barrier

Biologic
▪ Classification
• Human / porcine / bovine
• Cross-linked or non-crosslinked • Sterilization technique – gamma radiation/ ethylene oxide
▪ Consist usually of acellular collagen providing matrix for neovascularisation and native collagen deposition

▪ Utility
• Infected fields when synthetic mesh contraindicated
• However, expensive

Question 16

Management of wound dehiscence/burst abdomen

Answer 16

Preoperative management
o Cover eviscerated intestines with a saline-soaked sponge
o Fluid resuscitation
o Plan to return to operating theatre

• Definitive surgical management
o Explore abdomen to identify if a septic focus or anastomotic leak caused dehiscence
o Assess fascia
▪ If fascia adequate, primary closure is suitable
▪ If fascia is necrotic or infected – debride
o Consider options for closure
▪ Closure with synthetic absorbable mesh (polyglactin, polyglycolic acid) to bridge fascial defect
• Then advance skin edges +/- skin graft
• Repair of incisional hernia at a later date
▪ Leave open – laparostomy
▪ Temporary closure – open abdomen
▪ Closure with biological mesh
▪ Closure by negative pressure wound therapy

Question 17

Pathophysiology of abdo compartment syndrome

Answer 17

o Increasing abdominal volume leads to decreased compliance
▪ Reaches a point which will result in increase in IAP

o Diaphragm becomes displaced upwards
▪ Increased intrapleural pressure, decreased thoracic volume and compliance
▪ Causes hypoxia, hypercapnoea, acidosis

o IVC and portal vein compressed
▪ Reduced venous return
▪ Pooling of blood in splanchnic and peripheral veins
▪ Decreased cardiac output

o Compression of kidneys and decreased venous outflow
▪ Blood shunted from cortex to medulla causing GFR decrease, renal plasma flow, and urine output

o Mesenteric vasculature compression ▪ Mesenteric venous hypertension, decreased hepatic arterial flow
• Intramural acidosis, intestinal oedema, visceral swelling, intestinal permeability increased
• Bacterial translocation

o Raised CVP
▪ Cerebral pooling and increase in ICP
▪ Cerebral perfusion pressure decreases o IL6 and IL1b levels increase

o Abdominal wall blood flow decreases ▪ Increased risk of abdominal wound complications

Question 18

Aetiology of abdo compartment syndrome

Answer 18

Primary or secondary

o Primary:
▪ Pathological IAH due to intraabdominal pathology
▪ Eg damage control surgery after trauma
• → ileus caused by:
o small bowel oedema
o contamination
o ongoing bleeding /coagulopathy o capillary leak o massive fluid resuscitation / transfusion
• → contamination / bleeding / coagulopathy →

▪ Non trauma EG
• Ascites,
• Retroperitoneal haemorrhage, pancreatitis
• Pneumoperitoneum
• After reduction of chronic hernia after loss of domain
• AAA rupture repair
• Liver transplant

o Secondary:
▪ Absence of intraabdominal pathology ▪ EG:
• Aggressive fluid resuscitation for shock
• Thermal injury
• Critically ill hypothermic/ septic patients
• Cardiac arrest

▪ Pathology
• Shock and ischaemia → increased capillary permeability
o Crystalloid resuscitation + permeability + gut reperfusion → fluid exudate, interstitial oedema, bowel wall oedema, ascites

Question 19

Clinical presentation of raised intra abdo pressure, measurement and grading

Answer 19

Clinical signs
o Increasing respiratory requirements
o Oliguria
o Increasing vasopressor requirements
o Tense and distended abdomen
o Neurological deterioration
o CVP becomes elevated
o Acidosis occurs

• Measurement of IAP
o Foleys catheter disconnected from drainage tubing. Inject 50ml, clamp, then check pressure using needle
▪ Alternately, can use a 3 way attachment to allow pressure check through side port

• Grading of IAP
o 1: <10-15cmH2O (12-15mmHg)
o 2: <16-25cmH2O (16-20mmHg)
o 3: <26-35cmH2O (21-25mmHg)
o 4: >36cmH2O (>25mmHg)

Question 20

Management of abdo compartment syndrome

Answer 20

Primary prevention of ACS
o Open abdomen after high risk procedures
o Close monitoring of patient at risk for secondary ACS receiving crystalloid resuscitation

• Conservative measures to reduce IAP / prevent progression
o Conservative fluid resuscitation
o Analgesia
o Sedatives/ paralysis
o Positioning
o Drainage of abdominal fluid
o Escharotomy
o Renal replacement therapy, Diuretics

• Indications for decompression in ACS
o Tense abdomen with IAH grade 3 and evidence of organ dysfunction (ventilatory dysfunction, oliguria)
o Grade 4 IAH with ventilatory and renal failure
o Head injury with IAP >20
o Intractable intracranial hypertension without head injury

• Indications for laparostomy
o To allow pus or enteric contents to drain
o To avoid closure under tension
o Planned re-look surgery
o Abdominal compartment syndrome

Question 21

Risks of laparostomy

Answer 21

o Fluid and evaporative losses
o Increased risk of bowel injury and fistulas
o Challenging to nurse
o Delayed healing
o Risk of hernia

Question 22

Closure options following laparostomy

Answer 22

Temporary closure
o Bogota bag
▪ Large translucent bag sutured to fascia or skin to contain bowel

o Patch techniques
▪ Interposition of prosthetic mesh material between fascial edges

o Biologic mesh

o NPWT
▪ Towels covered in ioban
▪ Vac-dressing

Definitive closure
o Primary fascial closure
▪ May reinforce with mesh (usually biological due to infected space)
▪ May require component separation

o Functional closure
▪ Bridge defect with biological mesh (interposition, in-lay)
▪ Skin closed over mesh
▪ Ventral hernia will develop

o Planned ventral hernia – plan for skin coverage and elective hernia repair in 6-12 months
▪ Skin only closure
▪ Skin graft

Question 23

Obturator hernia

Answer 23

Hernia through obturator canal
o At union of pubic bone and ischium
o Canal usually covered by membrane
▪ Pierced at medial and superior borders by obturator nerve and vessels
▪ Weakening of membrane causes enlargement of canal and thus formation of hernia

o Hernia boundaries
▪ Obturator externus (posterior)
▪ Pectineus (anterior)
▪ Adductor brevis/adductor longus
▪ Usually anteromedial to nv bundle

• Clinical
o Usually elderly females with recent weight loss
o Can present with incarceration and strangulation
▪ 50% present with complete or partial obstruction
o Thigh ecchymoses
o Thigh mass
o Howship-Romberg sign
▪ Pain in anteromedial aspect of thigh due to compression of obturator nerve relieved by thigh flexion
o Hannington-Kiff sign
▪ Loss of adductor reflex but preservation of patellar reflex

o CT to confirm diagnosis

• Management
o Open or laparoscopic repair
o Posterior approach preferred
o Suture repair or with mesh covering defect after taking down peritoneum

Question 24

Hydrocele

Answer 24

• Definition
o Fluid collection between layers of tunica vaginalis within scrotum or cord

• Epidemiology
o Primary hydrocele - children or men >40
o Secondary hydrocele – age 20-40

• Aetiology
o Primary
▪ Children (communicating hydrocele) • Patent processus vaginalis
▪ >40y
• Decreased absorption of secreted fluid
• Idiopathic

o Secondary
▪ (non-communicating)
▪ Infection
• Filariasis
• Viral
• Bacterial – epididymoorchitis
▪ Trauma
▪ Torsion
▪ Neoplasm

• Clinical
o Scrotal swelling
o Can by painful/uncomfortable or asymptomatic
o Fluctuant/ transilluminates
o Can get above it
o Testis often not palpable

• Ix
o US to confirm diagnosis

• Mx
o Children
▪ Spontaneously resolve usually by age 2
o Symptomatic
▪ Scrotal exploration/ hydrocele cure

Question 25

Varicocele

Answer 25

• Definition
o Dilated tortuous veins of pampiniform plexus

• Epidemiology
o 25% men have small asymptomatic
o 40% in infertile men
o L>R

• Aetiology
o Incompetent venous valves
o Obstructing retroperitoneal pathology ▪ Vascular invasion
▪ Sarcoma
▪ Lymph nodes

• Clinical
o Heaviness or aching in scrotum after standing
o Bag of worms o Infertility

• Ix
o Ultrasound to confirm

• Mx
o Asymptomatic – non operative
o Symptomatic
▪ Ligation of ipsilateral testicular vein via inguinal incision
▪ Lapoaroscopic approach
▪ Trancutaneous embolization

• Complications
o Testicular atrophy
o Hydrocele
o Recurrence

Question 26

Testicular tumour

Answer 26

• Epidemiology
o Incidence 5/100 000 men

▪ 5% stromal (Leydig) or sex cord (Sertoli) ▪ 95% germ cell origin
o Most common tumour in men aged 20-40
o Seminomas tend to occur in older males

• Risk factors
o Cryptoorchidism
o Family history
o Syndromes with testicular dysgenesis (Klinefelters)

• Classification
o Seminoma (50%)
▪ Classic (85%), anaplastic or spermatocytic (15%)
o Non-seminomatous germ cell tumours (50%)
▪ Embryonal, yolk sac (endodermal sinus tumours), choriocarcinoma, teratoma, mixed

• Pathology
o Pathway of metastatic disease
▪ Retroperitoneal lymph nodes
• Right: infrarenal interaortocaval nodes → paracaval nodes → para-aortic nodes
• Left → para-aortic nodes → interaortocaval nodes
▪ Choriocarcinoma spreads early via haematogenous pathways
▪ Subsequent haematogenous spread to: lung, liver, brain, bone, kidney, adrenal

Clinical
• History
o Painless testicular mass
▪ 40% tender
▪ May have associated hydrocele

o Symptoms of metastatic disease
▪ Abdominal mass
▪ Shortness of breath
▪ Haemoptysis
• Investigations

o Ultrasound
o Tumour markers
▪ AFP ▪ bHCG ▪ LDH

Management
• Cryopreservation of sperm
• Radical inguinal orchidectomy for any solid testicular lesion
• Staging
o CT chest / abdo / pelvis
o Clearance of tumour markers from blood
▪ Bhcg – half life of 24-36h (choriocarcinoma)
▪ Afp – 5-7 days (yolk sac tumour)
o TNM

Further treatment based on stage
o Seminoma – (radiosensitive)
▪ IA / IB → surveillance OR regional lymph node RTx OR carboplatin CTx
▪ IIA / IIB → regional lymph node RTx OR cisplatin based CTx
▪ IIC / III → platinum based CTx AND resection of residual masses

o NSGCT
▪ I → surveillance OR RPLND AND/OR cisplatin CTx
▪ IIA → RPLND AND/OR cisplatin CTx
▪ IIB → cisplatin CTx then RPLND or surveillance
▪ IIC / III → CTx AND resection of residual masses

• Note about RPLND
o Template driven removal of all retroperitoneal lymphatic tissue from renal vessels to aortic bifurcation
o More difficult if post chemotherapy
o Anaesthetic post bleomycin needs minimal oxygen exposure
o Preserve sympathetic chain to prevent retrograde ejaculation

• Future concerns
o Fertility preservation
o Radiotherapy risk of delayed second malignancy

Prognosis
• Stage 1 → 98-99% survival long term
• Stage 2 → 100% survival with radiotherapy (seminoma), 90-95% with standard care (NSGCT)
• Stage 3 → seminoma 90%, NSGCT 80-90%

Question 27

Measuring intra-abdominal pressure

Answer 27

– urinary bladder
▪ Sterile water 50ml intravesical
▪ Clamp foley
▪ Transduce pressure
- end of expiration
- supine
- zeroed at iliac creast in mid axillary line
- absence of active abdo muscle contraction