Sacrectomy for Primary Sacral Tumours

Primary sacral tumours amenable to sacrectomy are dominated by three diagnoses:

• Chordoma — the commonest primary malignant sacral tumour; arises from notochordal remnants in the midline, typically in patients in the sixth and seventh decades. Slow-growing, locally destructive, radioresistant and chemoresistant at conventional doses. Physaliphorous cells, brachyury-positive on immunohistochemistry.
• Chondrosarcoma — eccentric rather than midline; also radio- and chemoresistant, so surgical margin is again the decisive variable.
• Giant cell tumour (GCT) — younger patients (third and fourth decades), eccentric, lytic and expansile. Benign but locally aggressive; denosumab and serial embolisation have shifted many sacral GCTs away from sacrectomy toward intralesional surgery or non-operative control, because sacrificing continence for a benign tumour is rarely justified.

Core principle: for chordoma and chondrosarcoma the operation is planned backwards from the margin. The bony osteotomy level, the roots sacrificed, the amount of gluteus maximus and pelvic floor taken, and whether rectum must be resected are all dictated by achieving a wide margin — never by the desire to preserve function.

Biopsy

• CT-guided core needle biopsy through a posterior midline transtumoural tract, placed in the line of the future incision.
• The tract is considered contaminated and is excised en bloc with the specimen.
• Never transrectal, transvaginal or transperitoneal — contamination of these routes commits the patient to visceral resection or renders the tumour effectively unresectable with margin.
• Presacral masses discovered on rectal examination should NOT be biopsied through the rectum by non-oncology teams; refer intact to a sarcoma centre.

The sacral roots exit their foramina and merge to form the sacral plexus on pelvic surface of piriformis. The pelvic splanchnic nerves (S2-S4) carry parasympathetic supply to bladder, rectum and erectile tissue; the pudendal nerve (S2-S4) supplies the external sphincters and perineal sensation.

Approach selection summary: posterior-only is feasible when the anterior tumour extent is modest, the rectal plane is free and vascular control from behind is realistic (generally low and mid lesions). Combined staged anterior-posterior surgery is chosen for high/total sacrectomy, bulky presacral disease, rectal involvement (en bloc rectal resection with colostomy), re-resection after contamination, or post-radiotherapy tissue.

• Sacral GCT: first-line is usually denosumab with or without serial embolisation and, if surgery is needed, nerve-sparing intralesional excision; sacrectomy with sphincter sacrifice for a benign tumour only in exceptional, refractory, destructive disease.
• Chordoma/chondrosarcoma, resectable with acceptable morbidity: en bloc wide resection is the standard of care.
• Chordoma requiring bilateral S2 sacrifice or S1 body resection: discuss in a multidisciplinary sarcoma meeting; options are total sacrectomy accepting complete deficit versus definitive carbon-ion or high-dose proton radiotherapy, which achieves durable local control in a meaningful proportion of patients and is favoured for surgically unfit patients, patients declining sphincter loss, and some high sacral tumours.
• Adjuvant radiotherapy: high-dose photon/proton therapy is commonly added for close margins or after any contamination; pre-operative radiotherapy protocols exist in some centres but raise wound risk.
• Recurrent chordoma: re-resection is rarely curative once the field is contaminated; particle therapy and systemic options (brachyury-targeted trials, imatinib historically with modest activity) are considered.

• Epidemiology: chordoma incidence is roughly one per million per year worldwide; sacrococcygeal disease accounts for about half of chordomas, with male predominance and peak in the sixth to seventh decades. Sacral chondrosarcoma and GCT are rarer at this site.
• Society guidance: ESMO/EURACAN and Chordoma Global Consensus Group guidance emphasise referral of presacral masses to sarcoma centres before biopsy, trocar/core biopsy through a resectable posterior tract, en bloc resection with wide margins as standard for chordoma, and high-dose particle therapy (proton or carbon-ion) as definitive treatment where resection is not feasible or declined. NCCN bone tumour guidance mirrors these principles. BOA/BSG sarcoma pathways in the UK mandate management within designated sarcoma networks.
• Registries and multicentre series: there is no arthroplasty-style implant registry for sacrectomy; evidence rests on multicentre collaborations — AOSpine Knowledge Forum Tumour primary spinal tumour cohorts, Rizzoli Institute and Memorial Sloan Kettering chordoma series, and Japanese and Italian carbon-ion cohorts (NIRS/QST Chiba, CNAO Pavia).
• Practice variation by resource setting: carbon-ion facilities exist in only a handful of countries (Japan, Germany, Italy, Austria, China), so surgical resection remains the only curative option in most of the world; in low-resource settings, staged surgery, flap availability and intensive-care capacity constrain total sacrectomy, and non-operative palliation or referral abroad is common for S1-level disease. Denosumab access similarly determines whether sacral GCT is managed medically or surgically.

• Surgery versus particle therapy for high sacral chordoma: no randomised comparison exists; carbon-ion cohorts show competitive control without sphincter sacrifice, but long-term insufficiency fractures, nerve toxicity and salvage difficulty after radiotherapy failure remain concerns.
• Rigid spinopelvic reconstruction versus no reconstruction after total sacrectomy: rigid constructs restore load transfer but carry high hardware failure and infection rates; some series report acceptable ambulation without reconstruction.
• Extent of nerve sacrifice for margin: whether a planned marginal (rather than wide) plane over preserved S2/S3 roots is oncologically acceptable in selected chordomas is debated.
• Cell salvage and tumour surgery: traditionally avoided; leucocyte-depletion filters and irradiation of salvaged blood are used in some centres.
• Denosumab in sacral GCT: optimal duration, rebound after cessation, and whether it should replace surgery entirely in the sacrum remain unresolved.
• Prophylactic colostomy in total sacrectomy: reduces perineal wound soiling but adds morbidity; practice varies widely.