JOURNAL OF THE LOUISIANA STATE MEDICAL SOCIETY
chondrosarcomas, chordomas locally invade the intervertebral disc space as they spread, which can be visualized on computed tomography (CT) or MRI. Calcifications are present in 30-70% of chordomas. They are iso- or hypo-intense compared to muscle on T1 and hyperintense on T2-weighted MRI images. Definitive diagnosis is made by core needle biopsy. 5 Once a sacral chordoma is diagnosed, the patient should be referred to a tertiary care center for evaluation by experienced surgeons. The main prognostic factor across several studies is the extent of resection. 1-3,7,8 Local recurrence remains common but is affected by the resection margins. Margin classifications are based on the classifications by Enneking in 1980. A wide margin involves resection of the surrounding healthy tissue without entering the reactive zone surrounding the tumor, whereas a marginal margin extends through the reactive zone, and an intralesional margin enters the tumor. 9 With a wide margin the rate of local recurrence is 5-17%, compared to 71-81% for intralesional or marginal resection margins. Another potential complication is tumor seeding, which can occur due to intraoperative violation of the tumor capsule and can potentially increase the rate of local recurrence. 8 Seeding can also occur from tumor biopsy, therefore every effort should be made to resect the biopsy tract during tumor resection. The choice of surgical approach will be largely dictated by the experience of the surgeon(s) involved. Some centers advocate the use of the anterior-posterior combined approach, while others have foundnodifference in outcomes using the posterior- only approach regardless of tumor level. 3 A combined approach Figure 4 : Posterior lumbo-iliac fixation. The lumbar pedicle screws were connected to the most inferior pair of iliac screws with vertical rods. The superior two pairs of iliac screws were connected with horizontal rods with a fibular strut wired between the rods for additional pelvic stabilization.
allows for careful dissection of the pelvic neurovascular structures, especially when the tumor extends high into the pelvis. 8 The morbidity associated with extensive pelvic resection is generally quite high due to sacrifice of involved nerve roots and extensive muscular dissection. In our patient, using the combined approach allowed for a well-controlled resection with preserved ambulation using a walker, but at the expense of urinary continence. Classical chemotherapy has not been proven to be effective in these tumors; however there are some anecdotal reports of slowed tumoral progression with cisplatin, anthracycline, and alkylating agents. Current studies are aimed at identifying and targeting specific receptors expressed by the chordoma, with promising results from tyrosine kinase inhibitors such as imatinib and sumitinib. Cetuximab, gefitinib, and erlotinib target the epidermal growth factor pathway expressed by these tumors. Use of radiotherapy is controversial, and the radio- sensitivity of surrounding structures such as bladder, small bowel, and sacral plexus limits the extent of radiation therapy. 5 Recent studies have shown a statistically significant increase in overall survival and progression-free survival for patients who undergo total resection followed by proton beam therapy compared to patients with incomplete resection with or without proton therapy, indicating that surgical resection remains the most important variable. 1 Figure 5 : Postoperative x-ray demonstrating instrumentation from L3 to iliac crests. Vertical rods run along L3 to L5 and attach to the bottom-most pair of iliac screws. Horizontal rods connect the remaining two pairs of iliac screws with a fibular strut placed horizontally and wired to the two rods.
8 J La State Med Soc VOL 170 JANUARY/FEBRUARY 2018
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