Pelvic Wall Reconstruction

PELVIC WALL RECONSTRUCTION

INDICATIONS

·  Usually chronic wounds caused by infected orthopaedic hardware or infected THR

·  1-2% THR become infected

·  non-healing chronically infected wounds usually have a draining sinus with indurated woody surrounding tissues

·  polymicrobiol cultures

Girdlestone procedure

·  indicated in a severely infected or diseased hip joint where a hip prosthesis is not feasible

·  was commonly done for severe tuberculosis-induced destruction of the hip joint

·  Cavity is left to fill with scar. Femur rides upward, and the patient's leg shortens. People in this situation are able to walk very limited distances, using a walker and a shoe lift.

·  operation can be converted to a total hip replacement in many cases.

PRINCIPLES OF TREATMENT

·  Liase with orthopaedic team

·  Infected implant may require removal and replacement with antibiotic spacer in a two satge reconstruction

Debridement

·  Devitalised soft tissue, scar, bone and methylmethacrylate

·  especially important is complete removal of the methylmethacrylate and the infected and nonviable bone

Reconstruction

·  well vascularized tissue

·  fill dead space

·  wound closure

OPERATIONS

RECTUS FEMORIS FLAP

Anatomy

·  ASIS into the quadriceps patella tendon

·  Type II

·  Dominant by descending branch of lateral femoral circumflex artery

·  Enters the muscle 10cm below the ASIS

Reconstruction

·  Elevated through a lateral thigh incision

·  Based on the lat. Femoral circumflex artery

·  Sutured to the acetabulum

·  Vastus lateralis and vastus medialis are then approximated

VASTUS LATERALIS FLAP

Anatomy

·  Lateral surface of the greater tronchanter and the trochanteric line and inserts into the rectus femoris tendon and the upper lateral patella

·  Type I

·  Blood supply by the descending branch of LFCA-enters the muscle 10-12 cm below the origin

·  Distal 1/3 by perforating braches of the superficial femoral artery and thus only the proximally 2/3 can be reliably raised on the lat. Femoral circumflex artery

Reconstruction

·  Lateral incision

·  More difficult incision with firm vascular attachments to the femur

·  Can be used incombination with the rectus fomoris

·  Major drawback is significant weakness related to knee extension and lateral knee instability

·  May be used to cover the acetabulum after a Girdlestone procedure. Hamstrings also can be used.

RECTUS ABDOMINUS FLAP

TENSOR FACIA LATA

FREE MUSCLE TRANSFER

·  Latissimus dorsi

·  Rectus abdominus

·  Others

PELVIC WALL RECONSTRUCTION

INDICATIONS

·  Infection

·  Pressure necrosis

·  Radiation injury

·  Trauma

·  Residual defects post tumour excision

MECHANISM OF PELVIC TRAUMA

1.  lower extremity or pelvic avulsion by entanglement in machinery

2.  MVA causing sacroiliac joint disruption and pubic symphysis separation

3.  massive crush injuries to the groin disrupting the vessels, nerves, soft tissue, and pelvic bones

·  acute pelvic reconstruction is rare however the principles are the same as for large defects post tumour ablation

·  viable thigh musculature provides good options for soft tissue coverage

PELVIC TUMOURS

5-10% soft tissue and bone sarcomas involve the pelvis

remember primary and secondary tumours

preoperative imaging correctly establishes the extent of the resection and the subsequent defect needed to be reconstructed

preoperative planning is essential

hemipelvicectomy was the standard, now newer limb sparing operations (eg internal hemipelvectomy

ANATOMY (ESSENTIAL POINTS)

·  pelvic brim is formed by the sacral promontory, iliopectineal line and pubic symphysis

·  The true and false pelvis are below and above this line

·  Internal iliac divides into an anterior and posterior branch

1.  Anterior branch divides into the inferior gluteal, obturator, internal pudendal, umbilical, inferior vesical, middle rectal , uterine and vaginal

2.  Posterior branch into the superior gluteal, iliolumbar and lateral sacral arteries

OPERATIONS

Follow the reconstructive ladder

Usually non graftable bed with exposed bone, nerves, vessels, joints

Local muscle flaps for smaller defects:

1.  Gluteus maximus

2.  Rectus abdominus

3.  Rectus femoris

4.  Vastus lateralis

5.  Tensor fascia lata

6.  Gracilis

Fasciocutaneous flaps

1.  Anterolateral thigh flap

2.  Lateral thigh flap

3.  Medial thigh flap

4.  Anteromedial thigh flap

May require the use of prosthetic material

Close fascial and bony defects

for reconstruction divide the pelvis into anterior, lateral and posterior wall defects

ANTERIOR DEFECTS

Anterior pelvic resection is usually stable

Abdominoperineal hernias are problematic without reconstruction

Fascia needs to be incorporated in the recon to prevent hernias

Or in combination with the prosthetic mesh and muscle flaps

Attach mesh to the sacrum, coccyx, posterior iliac wings posteriorly and to the costal margin anteriorly and laterally to the iliac crest and abdominal fascia

Use omentum or rectus abdominus internally to prevent contact between the internal viscera and the mesh

Others options include

TFL

Rectus femoris

Gracilis

Sartorius

Vastus lateralis

Free tissue transfer

LATERAL DEFECTS

resection of all or part of the hemipelvis

depends on the extent and location of the tumour

smaller defects with a stable pelvis can be covered with local or free muscle transfer only

larger defects usually require amputation of the lower limb with extensive resection of the pelvis and soft tissues

HEMIPELVICECTOMY

·  radical requires resection proximal to sacroiliac joint

·  conservative involves preservation of part of the iliac bone

·  if tumour is in the groin or iliac fossa then an anterior flap is best

Posterior flap

based on gluteal vessels and gluteus maximus

indications

1.  primary tumour of the innominate bone or femur that have invaded the hip joint

2.  tumours of the upper thigh that extend through the obturator foramen into the pelvis

3.  anterior pelvic wall tumours

incisions start 5cm proximal and 2 cm medial to the ASIS

this incision follows the inguinal ligament to the pubic symphysis

posterior incision past to the greater tuberosity into the gluteal fold and around the perineum and upper thigh to meet the first

divide the rectus and abdominal wall muscles

the common iliac vessels divided as are the branches of the internal iliac vessels

posteriorly the gluteal fascia is divided and the gluteal and TFL raised on their pedicles

the nerves of the lower limb divided as is psoas

pubic symphysis, sacral nerve roots, pelvic diaphragm and sacroiliac joint is divided

the muscle then sutured to the anterior abdominal fascia

Anterior flap

primary indication are tumours that involve the upper thigh and buttock

Based on the rectus femoris muscle and perforators from the LCFA and superficial femoral arteries

incisions 2cm proximal and posterior to ASIS, parallels the inguinal ligament to pubic tubercle

longitudinal incisions posterior medially and posterior laterally and joined by a transverse incision above the patella

laterally incision parallels the iliac wing, then extends along the lateral aspect to the quadriceps insertion superior to the patella

release all the muscular attachments

deepen the anterior incision and raise the anterior myocutaneous flap based on the perforators of vastus lateralis and rectus femoris (SFA)

approximate the quadraceps fascia to the sacrum, quadratum lumborum, levator ani

closure over drains

INTERNAL HEMIPELVECTOMY

·  involves resection of the innominate bone and preservation of the lower extremity

·  incision follow iliac crest posteriorly and then posterior-laterally down the leg

·  variable amount of bone and soft tissue resection

·  hip joint reconstruction, local free tissue reconstruction

POSTERIOR DEFECTS

·  Usually result of resection of primary and secondary tumour resection

·  Complicated by injuries to the nerves to the rectum, bladder, and lower extremities

o  Resection below S3 urinary continence is maintained

o  If at S1, pelvic stability is maintained

o  If S1 and S2 is resected then bladder function is compromised

·  Investigations

CT

MRI

CXR

Bone scan

Plain xrays of the lumbo-sacral spine

Reconstruction

·  Gluteus maximus is the workhorse flap