Unresectable pelvic / proximal-thigh sarcoma · limb salvage not achievable
- An external hemipelvectomy removes the entire lower limb together with the ipsilateral hemipelvis. It is performed when a sarcoma of the pelvis or proximal thigh cannot be resected with limb salvage — typically because it encases the major neurovascular bundle, involves multiple pelvic compartments, or has complicated an attempted limb-salvage resection.
- The classic standard flap is the posterior (gluteal) myocutaneous flap, based on the superior gluteal artery from the internal iliac, used when the buttock is clear. When the tumour involves the gluteal region or its vessels, an anterior (quadriceps) flap based on the profunda femoris system is used instead.
- This is massive surgery with major blood loss: cross-match a large volume, use a cell saver, large-bore access, arterial and central lines, and plan post-operative ICU.
- Free the hemipelvis by dividing the pelvic ring at two points — the pubic symphysis anteriorly and the sacroiliac joint (or sacrum) posteriorly — after proximal control of the iliac vessels and protection of the ureter, bladder and bowel.
- Distinguish it from internal hemipelvectomy, which removes the pelvic tumour but preserves the limb. External hemipelvectomy is reserved for when limb salvage cannot achieve a functional, oncologically sound result.
When & Why
Indication. A malignant tumour of the pelvis or proximal thigh for which limb-salvage surgery cannot achieve a wide margin while leaving a functional limb, in a patient fit enough to survive the procedure. The vast majority are high-grade bone or soft-tissue sarcomas (osteosarcoma, chondrosarcoma, Ewing sarcoma, malignant peripheral nerve sheath tumour, large high-grade soft-tissue sarcomas) or, less often, a locally advanced recurrence. The clinical scenarios fall into three groups:
A resectable sarcoma where limb salvage is impossible — neurovascular encasement (the external iliac or femoral vessels and the sciatic and femoral nerves), multifocal pelvic involvement, failed or contaminated limb salvage, pathological fracture, or infection precluding reconstruction. Wide margins offer the chance of cure.
Intractable pain, a fungating or ulcerated tumour, uncontrolled haemorrhage or infection, or local recurrence after all other options are exhausted. The aim is symptom relief and dignity, accepting that a survival benefit is uncertain.
Historically performed for massive pelvic crush injury, intractable pelvic sepsis, or uncontrolled pelvic haemorrhage. Largely superseded by modern trauma and reconstructive techniques but still occasionally the only available option.
The key decision — limb salvage or amputation? Before offering a hindquarter amputation, confirm at the sarcoma MDT that an internal hemipelvectomy with limb reconstruction is not feasible. Limb salvage is preferred whenever a wide margin can be achieved with a functional limb. Amputation becomes the answer only when resecting the structures a functional limb depends on — both the principal artery and vein to the limb, or the sciatic and femoral nerves together with the acetabulum — would leave a dysvascular, insensate, flail extremity. Palliative cases bypass this test: symptom control is the goal. Pre-operative assessment. Treat this as a major physiological insult. - Staging and margins: high-resolution MRI of the pelvis for local extent and the compartments involved; CT chest (and whole-body imaging) for metastases; review the biopsy with the pathologist to confirm grade and margins; mark the biopsy tract so it is excised en-bloc.
- Plan the flap on the imaging: does the tumour involve the gluteal region and its vessels? If the buttock is clear, plan a posterior (gluteal) flap; if not, plan an anterior (quadriceps) flap. The flap choice dictates which vessels are preserved and which are divided.
- Systemic preparation: anaesthetic review, optimise cardiorespiratory and nutritional status, exclude distant disease; group-and-crossmatch a large volume of blood and arrange a cell saver; bowel preparation and mark a stoma site in case the pelvic viscera are involved.
- Counsel fully — the functional loss (the limb and the pelvic stability on that side), the long recovery, phantom and stump pain, the psychosocial impact, prosthetic options (often limited), and the realistic chance of cure versus palliation. Setup. Lateral or semilateral decubitus on a beanbag, secured but able to be tilted intra-operatively; the limb and pelvis are prepped free so they can be manipulated. Large-bore intravenous access, an arterial line, a central line, a urinary catheter and a cell saver are mandatory. A general anaesthetic with an epidural is typical, with antibiotics at induction. The whole team — surgeon, assistant, anaesthetist and scrub nurse — is briefed: this is a long, bloody operation.
The Operation
The goal: remove the lower limb together with the ipsilateral hemipelvis as a single specimen, achieving a wide margin, while leaving durable soft-tissue cover and protecting the pelvic viscera. Two osteotomies — through the pubic symphysis anteriorly and the sacroiliac joint posteriorly — release the hemipelvis from the ring, after the iliac vessels have been controlled and the ureter, bladder and bowel protected. The flap (posterior gluteal by default) is then rotated over the defect.
Anatomical diagram or intra-operative photograph of an external hemipelvectomy: the ipsilateral hemipelvis and lower limb delivered as a single specimen, with the two pelvic cuts visible at the pubic symphysis and the sacroiliac joint, the ligated iliac vessel stumps, and the posterior gluteal myocutaneous flap swung forward to cover the raw pelvic defect.
Context: A verified image is being sourced.
Operative sequence
- Lateral or semilateral decubitus, secured on a beanbag; the limb and hemipelvis prepped free.
- Mark the incisions for the chosen flap, designing it generously so it covers the defect without tension. Plan to excise the biopsy tract en-bloc with the specimen.
- Confirm cross-matched blood, the cell saver, invasive lines and warming are in place before the incision.
- Begin along the iliac crest: divide the abdominal-wall musculature (external and internal oblique, transversus) off the crest from the flank toward the pubis, exposing the iliac fossa and pelvic brim.
- Divide the inguinal ligament and develop the retroperitoneal plane medially to reach the iliac vessels.
- Identify, protect and gently retract the ureter. Identify the bladder and (on the left) the sigmoid, keeping them clear of the field.
- Expose the common, external and internal iliac vessels at the pelvic brim.
- For the standard posterior (gluteal) flap, ligate and divide the external iliac artery and vein (the limb's supply), while preserving the internal iliac artery and specifically the superior gluteal branch — it is the pedicle of the gluteal flap.
- For an anterior (quadriceps) flap, the profunda femoris system must be preserved to perfuse the flap; the internal iliac and gluteal vessels are divided with the specimen.
- Obtain control before any bone division, and double-ligate or transfix every large vessel.
- Retract the bladder medially and protect it. Develop the retropubic space.
- Divide the pubic symphysis with an osteotome, bone-cutting forceps or a saw, staying clear of the bladder and urethra.
- This opens the anterior pelvic ring. Anticipate bleeding from the retropubic venous plexus — diathermise and pack patiently.
- The level depends on tumour extent: through the sacroiliac joint for a clear margin, or through the lateral sacrum or iliac wing if the tumour demands it.
- Develop the plane, protect the lumbosacral trunk and sacral nerve roots where possible, and divide the joint or bone with an osteotome or saw.
- The hemipelvis is now free anteriorly and posteriorly.
- Divide the psoas and iliacus off the pelvic brim.
- Divide the femoral, obturator and sciatic nerves under tension so the cut ends retract into soft tissue away from the weight-bearing stump (this reduces symptomatic neuroma).
- Divide the pelvic-floor muscles, the sacrotuberous and sacrospinous ligaments, and any remaining posterior attachments. The limb-with-hemipelvis specimen is now delivered.
- Methodically check the raw pelvic surface and the vessel stumps; the cell saver and packing are your friends here.
- Orientate the specimen with orientation sutures and send it for margin analysis — a positive margin profoundly alters prognosis and adjuvant planning.
- Bring the chosen flap — the posterior gluteal myocutaneous flap by default — over the defect to cover the bony pelvis and vessel stumps without tension.
- De-epithelialise or contour the flap to create a smooth, durable stump; place suction drains beneath it.
- Close in layers over the drains and apply a bulky soft dressing. A well-padded, healed stump is the foundation of any later prosthetic use.
External hemipelvectomy crosses the rich vasculature of the pelvis — the iliac vessels, the retropubic venous plexus, and the gluteal and internal iliac branches. Anticipate major haemorrhage: large-bore access, arterial and central lines, a cell saver, adequate cross-matched blood, and continuous communication with anaesthetics throughout. Obtain proximal iliac control before dividing bone, ligate or transfix every named vessel, and pack patiently when the venous plexus bleeds. A second consultant and a rapid transfusion protocol should be immediately available.
The standard posterior gluteal flap relies on the superior gluteal artery (off the internal iliac) and is used when the buttock is clear. When the tumour involves the gluteal compartment or its vessels, switch to an anterior quadriceps flap fed by the lateral circumflex femoral branch of the profunda femoris. Deciding the flap pre-operatively on MRI — and preserving the vessels it depends on — is what makes the difference between viable, durable cover and flap necrosis.
Examiners want to hear that the hemipelvis is released by dividing the pelvic ring at two points: the pubic symphysis anteriorly and the sacroiliac joint posteriorly, with the posterior level adjusted to the tumour. State plainly how you protect the bladder and urethra at the symphysis and the sacral roots at the sacroiliac joint.
Aftercare & Complications
Rehabilitation | Phase | Timing | Focus | Key actions | |-------|--------|-------|-------------| | 1 | 0 to 2 weeks | Medical stabilisation; flap and wound survival | ICU monitoring; flap checks; analgesia including a gabapentinoid; VTE prophylaxis; gentle log-rolling | | 2 | 2 to 6 weeks | Wound healing and early mobility | Drain removal as output settles; supervised sitting and transfers; protect the flap from shear | | 3 | 6 to 12 weeks | Strengthening and independence | Wheelchair mobility mastered; core and upper-limb conditioning; stump desensitisation | | 4 | 3 to 6 months and beyond | Prosthetic consideration | Stump maturation; trial of a hindquarter (tiltable) prosthesis if motivated and fit; many patients elect ongoing wheelchair use | Walking with a hemipelvectomy prosthesis is energetically very expensive, because the pelvis on that side is gone and the prosthesis must span from the trunk to the floor; a substantial proportion of patients function best with a wheelchair and are fully independent in it. Phantom-limb and stump pain are common and deserve early, aggressive, multimodal management. Psychological support and contact with other amputees are part of the treatment, not an optional extra. Complications
| Complication | Recognition | Prevention | Management |
|---|---|---|---|
| Major haemorrhage | Intra-operative blood loss; post-operative hypotension with a rising drain output or an expanding mass | Proximal iliac control before bone cuts; cell saver; large cross-match; rapid transfusion protocol | Immediate resuscitation; re-explore for a slipping ligature; interventional radiology for the stable bleeder |
| Flap necrosis | Dusky, blistered or frankly non-viable flap edge; delayed healing; serous or purulent discharge | Design a generous, tension-free flap; preserve its pedicle; avoid pressure and shear post-operatively | Debride non-viable tissue; negative-pressure therapy; revise or skin-graft; rarely a free flap |
| Wound infection or pelvic abscess | Erythema, fever, rising inflammatory markers, purulent drainage | Prophylactic antibiotics; meticulous haemostasis; minimise dead space with drains | Wound exploration and debridement; targeted antibiotics; drainage of a pelvic collection |
| Phantom-limb and stump pain | Burning, shooting or crushing pain in the absent limb or stump, often early and persistent | Divide nerves under tension so ends retract into soft tissue; perineural analgesia; early multimodal pain control | Gabapentinoids, opioids sparingly, desensitisation, neuromodulation; treat a neuroma if localised |
| Symptomatic neuroma | Focal Tinel tenderness at a stump nerve end with referred pain | Divide nerves under tension away from pressure points; bury the nerve end | Ultrasound-guided injection; excision and burial of the nerve end if refractory |
| Pelvic hernia or visceral injury | Bulging at the defect; bowel or bladder symptoms; obstruction | Close the pelvic-floor defect in layers; protect the ureter, bladder and bowel throughout | Repair the hernia; manage any visceral injury with general surgical support |
| Venous thromboembolism | Calf pain and swelling, dyspnoea, pleuritic chest pain | Early mobilisation; mechanical and pharmacological prophylaxis | Anticoagulation per protocol; investigate a suspected PE urgently |
Viva & Exam Focus
AMPUTEAMPUTE — the operative sequence of hindquarter amputation
Clinical Decision Scenarios
Practise clinical reasoning and management decisions out loud
“A 45-year-old man has a high-grade osteosarcoma of the periacetabular ilium extending into the hip and proximal thigh and encasing the external iliac vessels and sciatic nerve. Staging is otherwise clear. Outline your management and why you would offer a hindquarter amputation rather than limb salvage.”
“A 62-year-old has a large recurrent soft-tissue sarcoma of the buttock infiltrating the gluteal muscles and encasing the superior gluteal vessels. You need a hindquarter amputation. How do your flap choice and vascular strategy change?”
Indication
- A pelvic or proximal-thigh sarcoma where limb salvage cannot achieve a wide margin with a functional limb
- Curative (clearance) or palliative (pain, fungation, haemorrhage)
- Confirm at the MDT that internal hemipelvectomy is not feasible
The key anatomy
- Two pelvic cuts free the ring: the pubic symphysis anteriorly and the sacroiliac joint posteriorly
- The vessels are controlled at the iliac bifurcation
- Protect the ureter, bladder and bowel; divide the femoral, obturator and sciatic nerves under tension
Flap choice
- Standard: posterior gluteal flap on the superior gluteal artery (internal iliac) when the buttock is clear
- Alternative: anterior quadriceps flap on the profunda femoris when the gluteal region or vessels are involved
- The flap decides which vessels are preserved and which are divided
Hazards and aftercare
- Anticipate massive haemorrhage: cross-match, cell saver, large-bore access, ICU
- Leading complications: flap necrosis, infection, phantom and stump pain
- Prosthetic use is energy-expensive; many patients do best with a wheelchair
Background & Evidence
Epidemiology. External hemipelvectomy is a rare operation performed only in specialist sarcoma centres. Its frequency has fallen steadily as limb-salvage surgery — internal hemipelvectomy with allograft, endoprosthetic or saddle reconstruction — has become safer and more widely available, so it is now reserved for the minority of tumours that genuinely cannot be resected with the limb. Most candidates are adults with high-grade pelvic or proximal-thigh sarcomas, and outcomes depend overwhelmingly on histology, grade, the margin achieved and the presence of metastatic disease rather than on the amputation itself. Pathoanatomy — why limb salvage sometimes fails. The pelvis is a ring that transmits the femoral nerve and the external iliac vessels into the lower limb and the sciatic nerve out through the greater sciatic notch. A tumour that encases the external iliac or femoral vessels, or the sciatic and femoral nerves, or that destroys the acetabulum and crosses compartments, cannot be excised with the limb intact while preserving a functional extremity. Resecting both the principal artery and vein, or both major nerves, leaves a dysvascular or anaesthetic limb that is a liability rather than an asset. In those patients, removing the limb with the hemipelvis gives the best chance of local control and a functional — if prosthetically demanding — outcome. Contrast with internal hemipelvectomy. Internal hemipelvectomy excises all or part of the hemipelvis for tumour but preserves the limb, reconstructing the pelvic ring or the hip as needed. It is the limb-salvage counterpart and the default whenever margins allow. The Enneking classification of pelvic resections — by the region resected — frames both operations.
| Region | Bony resection | Relevance |
|---|---|---|
| Type I | Iliac wing | May be resected internally for limb salvage or as part of a hindquarter amputation |
| Type II | Periacetabulum (hip) | Removal sacrifices the hip; reconstructed in salvage, taken with the limb in an external hemipelvectomy |
| Type III | Pubis and ischium | Often resectable in isolation for a pubic tumour with the limb preserved |
| Type IV (sacral extension) | Lateral sacrum | Added when tumour crosses the sacroiliac joint; the posterior osteotomy in a hemipelvectomy may run through here |
| Full hemipelvectomy | Types I plus II plus III together | Removes the entire innominate bone with the limb — the external (hindquarter) amputation |
References
Resection and reconstruction for primary neoplasms involving the innominate bone
Established the regional classification of pelvic resections (Type I ilium, II periacetabular, III pubis) and the concept of limb-salvage internal hemipelvectomy — the framework examiners still use.
The technique and management of the hindquarter amputation — original description
The classic original description of the hindquarter amputation, defining the operation and its anterior and posterior approaches.
Variants of hemipelvectomy
Described the surgical variants of hemipelvectomy, including the anterior flap technique used when the gluteal vessels and posterior compartment are involved by tumour.
Complications and outcome of external hemipelvectomy in a consecutive series of patients
A large consecutive series reporting that wound complications and flap necrosis were the dominant morbidity, with peri-operative mortality reduced in a modern specialist setting.