Hemipelvectomy and Hindquarter Amputation

Definition

Hemipelvectomy refers to surgical resection of part or all of one hemipelvis, performed primarily for malignant bone and soft tissue tumours. The procedure is classified as:

• Internal hemipelvectomy: Resection of pelvic bone with preservation of the ipsilateral lower limb (limb-sparing surgery)
• External hemipelvectomy: Complete amputation through the hemipelvis, removing the entire lower extremity (hindquarter amputation)

Epidemiology

Historical Context

• First hindquarter amputation: Billroth (1891)
• Development of limb-sparing techniques: 1970s-1980s with advances in chemotherapy and imaging
• Current limb salvage rate: 60-70% for pelvic tumours at specialised centres

Indications for Hemipelvectomy

Contraindications

Tumour-Specific Considerations

Critical Vascular Anatomy

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Pelvic Zones (Enneking-Dunham Classification)

The Enneking-Dunham classification divides the pelvis into anatomical zones for surgical planning:

Imaging

Biopsy

Staging Workup

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A destructive periacetabular or iliac lesion is not automatically a primary sarcoma. Distinguishing the differentials below determines whether hemipelvectomy is even appropriate.

Preoperative Preparation

Surgical Steps by Resection Type

Reconstruction Options for Type II Defects

Indications for Hindquarter Amputation

Primary Indications:

• Tumour involving sciatic nerve and/or external iliac vessels
• Extensive soft tissue sarcoma precluding limb salvage
• Failed internal hemipelvectomy with recurrence
• Uncontrolled infection with tumour

Surgical Technique

The topic repeatedly names the presacral venous plexus as the major bleeding source and quotes 3-10 litres of blood loss, but never develops how to control it - which is the single most important intraoperative survival skill in pelvic tumour surgery and a classic viva question.

• Why it is so dangerous. The pelvic veins - the presacral (sacral) venous plexus and internal iliac (hypogastric) veins - are a valveless, high-flow, low-pressure network that communicates with the vertebral (Batson) and basivertebral plexuses. A torn presacral vein retracts into the sacral foramen and cannot be clamped or ligated; blind clamping tears it further and endangers the sacral nerve roots. This is why it bleeds catastrophically and why conventional vascular control fails.
• Prevent it - proximal control first. Gain early retroperitoneal control of the common and internal iliac vessels BEFORE mobilising the tumour, and ligate the internal iliac artery (and vein) on the resection side. Consider preoperative selective arterial embolization (internal iliac) to cut inflow; some centres use intraoperative aortic or internal-iliac balloon occlusion for temporary inflow control during the critical resection.
• When presacral venous bleeding starts - do NOT blindly clamp. Apply direct pressure/packing first to control while the anaesthetist catches up. Definitive local options include sterile thumbtacks or bone wax pressed into the bleeding sacral foramen/cortex, muscle-fragment "welding" (a rectus/muscle pledget pressed onto the bleeding point and cauterised), and topical haemostatic agents. If it remains uncontrolled, pack the pelvis and use damage control - temporary closure, resuscitate on ICU, and a planned re-look at 24-48 hours.
• Resuscitate in parallel. Activate the massive transfusion protocol, give tranexamic acid, run the cell saver, and actively prevent the lethal triad of hypothermia, acidosis and coagulopathy.

The Type IV tab states that "S1 root sacrifice affects ankle dorsiflexion" and "S2-S4 sacrifice affects bladder/bowel function", but the functional consequences of sacral resection - central to consenting a Type IV or extended hemipelvectomy - are never developed (there is no dedicated sacrectomy topic to carry them).

• The single most important rule: unilateral is far better tolerated than bilateral. One intact side can maintain continence and useful function, so unilateral sacral-root sacrifice is generally acceptable, whereas bilateral loss of S2-S4 produces a neurogenic bladder and bowel and sexual dysfunction.
• Continence (bladder / bowel / sexual): S2-S4. These roots (parasympathetic plus the somatic pudendal supply) govern continence. As a working guide, preserving both S2 roots and at least one S3 usually maintains bladder and bowel control; bilateral sacrifice at or above S2-S3 does not. Counsel explicitly and plan for possible intermittent catheterisation or a stoma.
• Ambulation / motor. Useful gait needs the L5 and S1 roots; S1 contributes to plantarflexion (gastrocnemius-soleus) and hip/pelvic stability, so its preservation matters for walking. Resections below S1 typically preserve ambulation.
• Spinopelvic stability. A high sacral resection (through or proximal to S1, or crossing both sacroiliac joints) disconnects the spine from the pelvis - spinopelvic (lumbopelvic) dissociation - and requires lumbopelvic reconstruction/fixation (lumbar pedicle plus iliac screws, with or without fibular/allograft struts). Lower resections that keep S1 and at least one SI joint usually do not need spinopelvic fixation.

Intraoperative Complications

Early Postoperative Complications

Late Complications

Prognostic factors (most to least powerful): histological grade, then surgical margin status, then tumour size and stage, then anatomical resectability. Achieving a wide margin while preserving the limb is the central goal; amputation is justified when salvage would compromise the margin in high-grade disease.

Global Epidemiology

• Pelvic and sacral sites account for roughly 10-15% of all primary bone sarcomas.
• Chondrosarcoma is the most common primary pelvic bone sarcoma in adults; osteosarcoma and Ewing sarcoma predominate in adolescents and young adults.
• Bimodal age distribution: peak in the 2nd-3rd decade (Ewing/osteosarcoma) and 5th-7th decade (chondrosarcoma), with a slight male predominance.
• Pelvic sarcomas carry worse local control and survival than appendicular sarcomas because deep location delays diagnosis and complex anatomy limits achievable margins.

Guideline Comparison (Side by Side)

Registry and Outcome Signals

• Volume-outcome relationship: national audits and sarcoma networks consistently show better local control and survival when pelvic sarcoma surgery is concentrated in high-volume reference centres.
• Reconstruction durability: implant and reconstruction outcomes are tracked in institutional and national bone-tumour databases rather than standard arthroplasty registries (NJR/AJRR/AOANJRR exclude most tumour endoprostheses); reported pelvic endoprosthesis infection rates are far higher than primary THA.
• Functional benchmark: MSTS and TESS scores after internal hemipelvectomy typically cluster around 60-77%, versus markedly lower self-reported function and prosthetic use after external hemipelvectomy.

High- vs Limited-Resource Practice Variation