Chordomas persist as one of the rarer malignancies, accounting for approximately 1% to 4% of primary bone cancers.1 When chordomas occur, these tumors localize predominantly in the sacrococcygeal region.2 In addition to the urgency for addressing a relatively fast-growing tumor, the anatomical complexity of this area complicates the potential treatments. Furthermore, because of the lack of definitive symptoms, diagnosis is often difficult and typically occurs later in the disease progression.3 An aggressive treatment approach is often warranted because of the biologically aggressive nature of this disease. Full or partial sacrectomy is often the only option that offers the possibility of a long-term cure.4 A sacrectomy is a destructive procedure that can lead to mechanical instability depending on the extent of the surgical resection. When the entire sacrum is removed, there is an obvious need for lumbar-pelvic fixation; however, traditionally, partial sacrectomy procedures have been successfully performed without the need for instrumentation.3,4
This report describes the case of a patient with a noninstrumented sacrectomy procedure distal to the S2 foramen that resulted in an insufficiency fracture. The patient provided written informed consent for print and electronic publication of this case report.
Case Report
A 66-year-old woman presented with severe lower back pain of a month’s duration. Her pain was localized to the coccyx area and did not radiate to the lower legs. Although the pain could not be elicited by palpation, pain occurred when sitting and increased when standing for prolonged periods. Three weeks prior to the patient’s initial office visit, she noticed transient constipation and urinary retention. She denied any fever, chills, nausea, vomiting, unexplained weight loss, weight gain, and abdominal pain. There were no motor deficits in the lower limbs. Sensation was intact in the lower limbs except for the posterior aspect of the left leg down to the popliteal fossa, where light touch perception was absent. She recalled the loss of sensation in this area 20 years earlier, and it had neither progressed nor abated since then. She had a history of osteoarthritis and had been diagnosed with degenerative disc disease 20 years ago.
A radiographic review of her lumbar spine showed significant spinal stenosis and degenerative disease of the lumbar spine on non–contrast-enhanced magnetic resonance imaging (MRI). The MRI also revealed a large, soft-tissue mass at the S3-S4 level, eroding most of the S3 vertebral body and extending into the S4 vertebral body. The MRI images used for this analysis were insufficient in providing a complete portrayal of the entire mass. Because of these uncertainties, contrast-enhanced and non–contrast-enhanced pelvic MRIs were taken. The MRI analyses identified a mass density replacing the lower sacrum and upper coccyx that was bright in intensity on T2 and dim on T1 sequences. Sagittal imaging measurements were 5.9×2.5 cm and 4.4 cm right-to-left on coronal imaging. The mass extended beyond the involved sacrococcygeal segments and dorsally beyond the normal cortical margin of the sacrum and coccyx (Figures 1A, 1B). Next, a computer tomographic–guided needle biopsy through a posterior paraspinal approach was obtained. The biopsy consisted of fragments of a malignant neoplasm consistent with physaliferous cells. The specimen was positive for pankeratin, keratin AE1/AE3, epithelial membrane antigen, and S100 protein. This supported a diagnosis of a sacral chordoma. An en bloc sacrectomy at S2; lumbar laminectomy at L5, S1, and S2; and thecal sac transection at the S3 nerve roots were planned.
Surgical Procedure
The patient was placed in the prone position after a colostomy and harvesting of a rectus flap in the supine position. A midline incision was made from the spinous process of L5 down through the tip of the coccyx, and soft tissues were elevated while maintaining hemostasis. The most distal part of the coccyx was transected, and using a combination of electrocautery and paraspinal elevators, rectal and peritoneal tissues were elevated off the ventral component of the coccyx until a hand could easily reach the bifurcation of the iliac vessels. Electrocautery transected paraspinal muscles at the S1 and S2 levels while the more cranial paraspinal musculature was elevated to allow for a laminectomy. The spinous processes were removed from L5 and the sacrum with a Leksell rongeur. A high-speed burr thinned the dorsal lamina components of L5, S1, and the leading edge of S2. The L5, S1, and S2 nerve roots were identified. The gluteal muscles were elevated and the sacral coccygeal ligaments were transected. After identifying the sciatic notches, the S2 nerves exiting the foramen were identified, followed out through the sciatic notch, and a wire was passed through this region. Three 2-0 silk ties were applied to the exposed portion of the S3 and S4 nerve roots, and the nerves were transected because they were integrally involved with the tumor. Using a series of high-speed burrs and osteotomes, lateral cuts were made through the sciatic notch. The sacrum was osteotomized at the S2 sacral foramen through the anterior component with an osteotome, while a hand protected the ventral structures. The remaining parts of the S3 and S4 dorsal nerve roots were transected. An incision through the peritoneum was made to access the rectus flap, and a plastic surgeon closed the wounds and secured the flap.