Pelvic Ring Reconstruction After Iliac or Iliosacral Resection of Pediatric Pelvic Ewing Sarcoma: Use of a Double-Barreled Free Vascularized Fibular Graft and Minimal Spinal Instrumentation

Pelvic and Perineal Reconstruction

LEARNING OBJECTIVES

After studying this article, the participant should be able to: 1. Classify types of bony pelvic resections. 2. Outline reconstructive options for pelvic and perineal defects. 3. Identify advantages and drawbacks of various reconstructive techniques. 4. Recognize the functional benefits of bony and soft-tissue reconstruction.

SUMMARY

Defects of the pelvis and perineum arise from tumors, trauma, infection, congenital differences, and gender incongruence. Pelvic resections can result in bony instability and soft-tissue deficiency. The goals of reconstruction are maintenance of spinopelvic continuity, elimination of dead space, resurfacing of cutaneous defects, and prevention of hernias. Perineal reconstruction has important functional considerations. Abdominoperineal resection and pelvic exenteration defects benefit from flap reconstruction to decrease pelvic wound complications. Vulvovaginal reconstruction is performed with flaps from the perineum, thigh, or abdomen. Scrotal and superficial penile defects are most commonly reconstructed with scrotal flaps and skin grafts. Total penile reconstruction most commonly uses a radial forearm free flap.

Reconstruction of Internal Hemipelvectomy Defects After Oncologic Resection

Internal hemipelvectomy is preferred to hindquarter amputation for pelvic tumor resection if a functional lower extremity can be obtained without compromising oncologic principles; multidisciplinary advances in orthopaedic and plastic surgery reconstruction have made this possible. The goals of skeletal reconstruction are restoration of pelvic and spinopelvic skeletal continuity, maintenance of limb length, and creation of a functional hip joint. The goals of soft-tissue reconstruction are stable coverage of skeletal, prosthetic, and neurovascular structures, elimination of dead space, and prevention of herniation. Pelvic resections are divided into four types: type I (ilium), type II (acetabulum), type III (ischiopubic rami), and type IV (sacrum). Type I and IV resections resulting in pelvic discontinuity are often reconstructed with vascularized bone flaps and instrumentation. Type II resections, which traditionally result in the greatest functional morbidity, are often reconstructed with hip transposition, allograft, prosthesis, and allograft-prosthetic composites. Type III resections require soft-tissue repair, sometimes with flaps and mesh, but generally no skeletal reconstruction. Extension of resection into the sacrum can result in additional skeletal instability, neurologic deficit, and soft-tissue insufficiency, necessitating a robust reconstructive strategy. Internal hemipelvectomy creates complex deficits that often require advanced multidisciplinary reconstructions to optimize outcomes and minimize complications.

Comparison of customized 3D-printed prosthesis and screw-rod-cage system reconstruction following resection of periacetabular tumors

Background and purpose

Various operative methods are used for reconstructing pelvic girdle after resection of primary malignant periacetabular tumor has been reported. The objective of this study was to evaluate the accuracy, effectiveness, and safety of customized three dimensional-printed prosthesis (3DP) in the reconstruction of bone defects compared with conventional reconstruction using the screw-rod-cage system.

Methods

A retrospective case–control analysis of 40 patients who underwent pelvic tumor resection and reconstruction with a customized 3D-printed prosthesis (3DP), or screw-rod-cage system (SRCS) between January 2010 and December 2019 was performed. The minimum follow-up time for patients alive was 2 years. Blood loss, operation time, complications, surgical margin, local recurrence, distant metastases, status at time of latest follow-up, MSTS-93 score, Harris hip score, and postoperative radiographic parameters were recorded. Moreover, overall survival, tumor-free survival, and prosthesis survival rates in both groups were compared.

Results

Customized 3DP reconstruction was performed in 15 patients, and SRCS reconstruction was done in 25 patients. The group of patients treated with customized 3DP reconstruction had significantly shorter operation time (323.7 ± 83.7 vs. 393.6 ± 98.8 min; P = 0.028) and more precise (all P < 0.05) radiographic reconstruction parameters than patients in the SRCS group. Fewer complications (P = 0.026), better MSTS score (P = 0.030), and better Harris hip score (P = 0.016) were achieved in the 3DP group. Furthermore, the survival rate of prosthesis was also significantly better in the 3DP group (P = 0.039). However, blood loss, surgical margin, local recurrence, distant metastases, and status at time of latest follow-up had no significant difference between two groups.

Conclusion

Compared with the screw-rod-cage system reconstruction, the customized 3D-printed prosthesis reconstruction is equally safe and effective, but it is more accurate and time-saving and is associated with fewer complications.

Surgical Treatment of Bone Sarcoma

Bone sarcomas are rare primary malignant mesenchymal bone tumors. The three main entities are osteosarcoma, chondrosarcoma, and Ewing sarcoma. While prognosis has improved for affected patients over the past decades, bone sarcomas are still critical conditions that require an interdisciplinary diagnostic and therapeutic approach. While radiotherapy plays a role especially in Ewing sarcoma and chemotherapy in Ewing sarcoma and osteosarcoma, surgery remains the main pillar of treatment in all three entities. After complete tumor resection, the created bone defects need to be reconstructed. Possible strategies are implantation of allografts or autografts including vascularized bone grafts (e.g., of the fibula). Around the knee joint, rotationplasty can be performed or, as an alternative, the implantation of (expandable) megaprostheses can be performed. Challenges still associated with the implantation of foreign materials are aseptic loosening and infection. Future improvements may come with advances in 3D printing of individualized resection blades/implants, thus also securing safe tumor resection margins while at the same time shortening the required surgical time. Faster osseointegration and lower infection rates may possibly be achieved through more elaborate implant surface structures.