A New Classification System for Sacropelvic Resection and Reconstruction
The classification system was developed at Mayo Clinic to improve communication among care team members, facilitate prediction of outcomes based on tumor type, and assist with planning for reconstruction.
Adam Driesman, MD, and Timothy B. Rapp, MD
Houdeck MT, Wellings EP, Moran SL, e al. Outcome of sacropelvic resection and reconstruction based on a novel classification system. J Bone Joint Surg Am. 2020 Nov 18;102(22):1956-1965. doi: 10.2106/JBJS.20.00135.
Houdeck et al have developed a classification system for spinopelvic malignancies to facilitate communication among the multidisciplinary team caring for these patients, provide prognostic goals based on tumor presentation, and assist with the planning of surgical reconstruction. In a recently published article, they review and describe the outcomes of patients after surgical resection of the pelvis using the classification system.
The Mayo Clinic classification for sacral tumor resection includes 5 types:
- Type 1 resection, which can be subclassified to A, B, and C, includes bilateral total and subtotal sacrectomy.
- Type 2 resection includes hemisacrectomy but spares the remaining ipsilateral portion of the pelvis for fusion to the lumbar spine.
- Type 3 resection involves hemipelvectomy, maintaining an intact contralateral sacrum in which the spine can be surgically fused.
- Type 4 is a total sacrectomy and external hemipelvectomy that can sometimes salvage the need for a colostomy.
- Type 5 resection is a hemicorporectomy that requires colostomy and urostomy.
The authors retrospectively reviewed the Mayo Clinic sarcoma registry and identified 196 patients who underwent oncologic sacrectomy between 2000 and 2017. This cohort included 20 type 1A patients, 5 type 1B patients, 104 type 1C patients, 29 type 2 patients, 32 type 3 patients, 5 type 4 patients, and 1 type 5 patient.
Overall, disease-specific survival was 66% at 5 years and 52% at 10 years, local recurrence-free survival was 77% at 5 years, and metastasis-free survival was 68% at 5 years. By resection type, disease-specific survival at 5 years was:
- 34% for type 1A
- 100% for type 1B
- 71% for type 1C
- 65% for type 2
- 57% for type 3
- 100% for type 4
- 100% for type 5
Complications occurred in the majority of patients: 153 patients (78%) experienced a complication, with 95 patients (48%) having a wound complication.
The authors were also able to make prognostic assumptions when utilizing this classification system. For example, they determined that in patients who underwent a type 1 resection, preservation of the L5 nerve roots resulted in higher Musculoskeletal Tumor Society scores and a greater likelihood of ambulation after the procedure.
En boc resection of sacropelvic tumors in hopes of achieving a cure is a rare procedure that requires a specialized multidisciplinary team found at tertiary care centers. This study by Houdek et al offers a helpful classification that describes a stepwise approach to surgical resection planning, with the goal of preserving as much patient function as possible after obtaining a cure.
Of note, there is significant perioperative morbidity for patients who undergo en boc resection of these tumors, and the study demonstrates sobering results for herculean measures to preserve survival. This is emphasized by the high rate of reoperation and the death of 3 patients in the perioperative period.
There are salient take-away points from the authors’ experience. First, this study demonstrates that preservation of the L5 nerve root is key in maintaining the patient’s ability to walk, even when the sciatic nerve is sacrificed. The authors also highlight reconstruction of the sacroiliac joint, as it is typically the only mechanical connection between the axial skeleton and any remaining lower extremity, particular if there is a resection above the S1-S2 vestigal disc.
Finally, this series shows the propensity for wound complications, which they propose is secondary to the prolonged nature of these procedure. The authors recommend considering 2-stage procedures after witnessing increased morbidity when performing this procedure in 1 setting.
This report is a welcome addition to the literature for a rarely performed procedure. Not only does it provide a classification system that can build on the example set by Enneking and Dunham in 1978,  but it also delivers a stepwise guide for sarcoma services with the goals of obtaining negative tumor margins and assisting with post-resection function.
Adam Driesman, MD, is an orthopedic surgery resident at NYU Langone Orthopedic Hospital, New York, New York. Timothy B. Rapp, MD, is an Associate Professor of Orthopedic Surgery and Chief of the Division of Orthopedic Oncology at NYU Langone Orthopedic Hospital, New York, New York.
Disclosures: The authors have no disclosures relevant to this article.
- Enneking WF, Dunham WK. Resection and reconstruction for primary neoplasms involving the innominate bone. J Bone Joint Surg Am. 1978;60 A(6):731-746. doi:10.2106/00004623-197860060-00002