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Chapter Summary
• Context: Sacrectomy is indicated primarily for primary sacral neoplasms (such as chordomas and sarcomas) and locally advanced or recurrent pelvic carcinomas (e.g., colorectal cancer). The central therapeutic goal is obtaining wide, clear surgical margins (R0 resection). Cortical bone invasion and high sacral involvement (S1/S2) are no longer absolute contraindications in the contemporary setting provided that an R0 margin is achievable and the patient presents adequate clinical status. Absolute contraindications encompass unresectable disease due to insurmountable neurovascular involvement, prohibitive clinical comorbidities for major surgery, distant metastases without survival or quality-of-life benefit, and informed patient refusal.
• Chapter Objective: This chapter provides comprehensive guidance on oncological sacrectomy, detailing indications, surgical planning, combined anteroposterior approaches, spinopelvic reconstruction strategies, functional outcomes, and complication management.
• Overview and FundamentalsConcepts and Indications Sacrectomy is primarily aimed at treating primary sacral neoplasms (such as chordoma and sarcoma) and locally advanced or recurrent pelvic carcinomas (e.g., colorectal cancer). The central therapeutic goal is obtaining clear margins (R0 resection). Cortical bone invasion and high sacral involvement (S1/S2) are no longer absolute contraindications in the contemporary setting if R0 margins are feasible and the patient has adequate clinical conditions. Absolute contraindications include unresectable disease due to insurmountable extensive neurovascular involvement, medical comorbidities prohibiting major surgery, distant metastasis without impact on survival or quality of life, and informed patient refusal. Planning and Approaches Approach selection depends on tumor height and need for visceral resection: Low resection (below S2 neural foramina): Can be performed via an isolated posterior approach, providing adequate margins for lesions up to the vestigial S2-S3 disc. High or total resection (above S1-S2): A combined two-stage anteroposterior approach is indicated. The anterior stage (midline laparotomy) allows visceral mobilization, internal iliac vessel ligation, and unicortical osteotomies for dural protection. The posterior stage is frequently performed after 48 hours. Surgical Technique and Spinopelvic Reconstruction The anterior approach involves isolating the femoral nerve and preparing a myocutaneous flap (e.g., vertical rectus abdominis myocutaneous - VRAM flap). The posterior approach (midline or "Mercedes" incision) requires sectioning piriformis and coccygeus muscles, sacrotuberous and sacrospinous ligaments, laminectomy, and double silk suture ligation of the dural sac in case of transection. When spinopelvic continuity is disrupted (resections at S1-S2 or above), instrumented reconstruction is mandatory. Fixation uses pedicle screws at the 3 to 4 most caudal lumbar levels combined with bilateral long iliac or S2-alar-iliac (S2AI) screws, reinforced by allografts or vascularized bone grafts. Correcting lumbosacral flexion positioning induced by the surgical table before final locking is fundamental to prevent iatrogenic kyphosis. Outcomes and Complications R0 resection is the strongest predictor of survival. In colorectal cancer, 5-year overall survival post-R0 is ~42%. In primary bone tumors, median survival reaches 70 months. Functionally, most patients (>80%) preserve independent ambulation, though assistive device dependence increases in high resections. Bladder dysfunction occurs in 8-23%, bowel dysfunction in 4-22%, and sexual dysfunction in up to 67%. Wound complications (dehiscence and infection) occur in up to 29% of cases. Perioperative mortality is approximately 1.1%. Technological Innovations Recent advances include 3D-printed patient-specific custom sacral implants based on finite element analysis, robotic surgery, intraoperative navigation, patient-specific cutting guides, and augmented reality, optimizing margin accuracy and structural stability.
• Clinical Application: Decision-making requires balancing the pursuit of R0 margins against functional sequelae resulting from nerve root sacrifice. The surgeon must align expectations with the patient regarding inevitable risks of bladder, bowel, sexual, and gait dysfunctions. During the procedure, meticulous hemostasis, correct spinopelvic alignment on the operating table to avoid iatrogenic kyphosis, and filling dead space with well-vascularized muscle flaps (VRAM or gluteus maximus) constitute critical steps to prevent mechanical failures, CSF leaks, dehiscence, and deep surgical site infections.
