Hemipelvectomy

Hemipelvectomy, also known as a pelvic resection, is a surgical procedure that involves the removal of part of the pelvic girdle. This procedure is most commonly performed to treat oncologic conditions of the pelvis.¹² Hemipelvectomy can be further classified as internal and external hemipelvectomy.¹² An internal hemipelvectomy is a limb-sparing procedure where the innominate bone is resected while preserving the ipsilateral limb.¹² An external hemipelvectomy involves the resection of the innominate bone plus amputation of the ipsilateral limb.¹²

Hemipelvectomy is generally reserved for the treatment of pelvic neoplasms.¹² Examples of malignancies that are treated with hemipelvectomy include osteosarcoma, chondrosarcoma, and Ewing's sarcoma.¹ Rarely, hemipelvectomy is performed in settings of traumatic injury and osteomyelitis.¹ Indications for external hemipelvectomy include neoplastic extension into the sciatic nerve, where loss of function of the lower extremity is anticipated.¹ Internal hemipelvectomy is preferred when complete resection of the tumor is possible without sacrificing the lower extremity.¹ If external hemipelvectomy cannot provide a greater degree of tumor resection compared to internal hemipelvectomy, internal hemipelvectomy is recommended.¹ Internal hemipelvectomy must only be considered when the surgical approach can ensure the preservation of critical neurovascular structures in the region.¹

As with any surgical procedure, risks include infection, blood loss, damage to surrounding structures, cardiac/pulmonary complications, and adverse reactions to anesthesia.

Complications of external hemipelvectomy include:¹²

• Disfigurement
• Loss of ambulation
• Phantom limb pain
• Bladder dysfunction
• Sexual dysfunction
• Bowel dysfunction

Complications of internal hemipelvectomy include:¹²

• Leg-length discrepancy
• 'Flail hip' or 'floating hip' (referring to hypermobility of the hip joint)
• Hip instability

Prior to performing a hemipelvectomy, surgeons must possess detailed knowledge of the pelvic anatomy and its relation to the pelvic tumor.¹ Imaging studies such as conventional radiography, computed tomography, and magnetic resonance imaging help the surgeon visualize the anatomy and its relationship to the local pathology.¹ Surgical oncology techniques are utilized when resecting tumors of the pelvis.¹ Such techniques ensure that adequate resection margins are obtained at the time of surgery to minimize tumor recurrence.¹

The Enneking and Dunham classification system was developed in 1978 to aid surgeons in characterizing pelvic resections.¹³⁴ This classification scheme breaks down pelvic resections into 3 subtypes: Type I, Type II, and Type III.¹³⁴ Type I resections involve removal of the ilium.¹³⁴ Type II resections involve removal of the peri-acetabular region.¹³⁴ Type III resections involve removal of the ischial and/or pubic region.¹³

Resection of pelvic bone typically requires subsequent reconstruction to ensure stability of the hip joint, particularly in internal hemipelvectomy.¹ Examples of pelvic reconstruction include the use of an allograft, autograft, or prosthesis to bridge the remaining ends of pelvic bone following resection.¹⁴ Arthrodesis is a technique that can be used in internal hemipelvectomy to fix the proximal femur to a segment of pelvic bone for the purposes of stabilizing the lower extremity.¹⁴

• 
  An x-ray of a limb-sparing hemipelvectomy on the left side of a male pelvis taken one month after surgery.
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  An x-ray of the same pelvis taken eighteen months after surgery highlighting the femur migration to its final resting place.