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© 1999 The Journal of Bone and Joint Surgery, Inc. Long-Term Survival Following Total Sacrectomy with Reconstruction for the Treatment of Primary Osteosarcoma of the Sacrum. A Case Report* , DURHAM, NORTH CAROLINAInvestigation performed at Duke University Medical Center, Durham
Osteosarcoma of the sacrum occurs in both primary and secondary forms, with the latter including those that develop following radiation therapy and those associated with Paget disease of bone. Osteosarcomas originating in the sacrum are very rare, and most cases in the literature have been grouped with osteosarcomas arising in the vertebral column9-11,13,25,26,32,34,37,40,43,45,50,52. Mortality has been high, which is to be expected in association with any so-called high-grade lesion, as these lesions have a high risk of metastasis and occur in a location that makes adherence to standard oncological principles difficult. Sacral tumors usually have reached an advanced stage and a large size by the time that they are diagnosed, and these conditions make the resection of the tumor technically demanding and the chance of achieving a wide margin less likely. The achievement of an adequate margin often leads to pelvic instability as well as to a loss of neurological function17-20,23. However, over the past few decades, improved techniques with acceptable morbidity have been developed to allow for more extensive sacral resections in the treatment of benign, extracapsular, destructive lesions and low-grade malignant lesions, including giant-cell tumors and chordomas4,7,8,15,19,23-25,27,31,32,34-36,38,41,42,45,46,48,49,51. A multidisciplinary approach including preoperative chemotherapy has increased the survival of patients who have osteosarcoma involving the appendicular skeleton22, which suggests the importance of achieving local control in the treatment of osteosarcomas involving the axial skeleton. This report describes a patient with primary osteosarcoma of the sacrum who, at the time of writing, had survived disease-free for more than seven years following neoadjuvant chemotherapy and total sacrectomy with reconstruction.
A sixteen-year-old male patient was first seen by us in October 1990 because of a six-month history of progressive low-back pain, centered over the right sacroiliac region, and pain in the posterior aspect of the right lower limb, extending from the thigh to the mid-part of the calf. The medical history was otherwise unremarkable. On physical examination, there was tenderness in the region of the right posterior superior iliac spine and the sciatic notch. Motor examination revealed normal findings. The straight-leg-raising test was positive for radiating pain in the posterior aspect of the lower limb with the limb elevated 45 degrees and the patient lying supine. There was radiating pain in the posterior aspect of the thigh when the knee was flexed 10 degrees from this straight, elevated position and pressure was applied with the fingertips to the popliteal fossa (the popliteal compression test). There was a decrease in the right ankle reflex. Plain radiographs revealed a blastic lesion in the right half of the sacrum, including the body and the ala, with indistinct margins, indicating an osteoblastic process (Fig. 1). A computerized tomographic scan showed a blastic lesion of the right sacral ala with an anterior soft-tissue component that crossed the midline and elevated the adjacent neurovascular structures (Fig. 2). A magnetic resonance imaging scan revealed a large mass involving the right half of the sacrum, with anterior soft-tissue extension effacing the fat plane adjacent to the right psoas muscle (Fig. 3). The mass was bright on T2-weighted images and was enhanced by gadolinium contrast medium administered intravenously. Examination of a specimen obtained by means of a computerized tomography-guided biopsy revealed sclerotic woven bone containing atypical hyperchromatic osteocytes. Atypical chondroid clefts were present, and numerous pleomorphic hyperchromatic cells with deeply eosinophilic cytoplasm and pleomorphic nuclei lined the osteoid. This is the appearance of an osteosarcoma.
A metastatic survey revealed no evidence of distant disease, and the patient was started on an eight-month course of chemotherapy consisting of four courses of ifosfamide (2.4 grams per square meter of skin) and mesna (480 milligrams per square meter of skin); two courses of Adriamycin (doxorubicin) (fifty milligrams per square meter of skin) and cisplatin (100 milligrams per square meter of skin); four courses of methotrexate (twelve grams per square meter of skin) and leucovorin (fifteen milligrams per square meter of skin); and two courses of bleomycin (fifteen units per square meter of skin), dactinomycin (0.6 milligram per square meter of skin), and cyclophosphamide (600 milligrams per square meter of skin). This therapy resulted in a positive response both clinically and on imaging studies: the anterior soft tissue receded, and the tumor demonstrated less intensity on T2-weighted magnetic resonance imaging scans and on magnetic resonance imaging scans made with contrast medium (Fig. 4). A two-stage resection was planned.
The first stage, a transabdominal approach, was performed on July 24, 1991. After protection of the neurovascular structures, the anterior sacroiliac ligament was incised on the left side, and on the right side an osteotomy was performed through the iliac wing, 1.5 centimeters lateral to the right sacroiliac joint. The disc at the lumbosacral junction was incised, and then the soft tissues (including the first through fifth sacral nerve roots) and both the piriformis and the coccygeus were divided. A polypropylene mesh was placed over the anterior surface of the sacrum to help to identify the appropriate plane of dissection during the second stage. One week later, on August 2, the resection was completed through a posterior approach. The iliac osteotomy was completed, and a laminectomy of the fifth lumbar vertebra was performed. The dural sac and the nerve roots were transected at the level of the mid-part of the body of the fifth lumbar vertebra, with preservation of the fifth lumbar nerve root. The dural sac was then closed with a running 6-0 Prolene (polypropylene) suture. The sacrococcygeal joint was disarticulated, and the sacrum, the right sacroiliac joint, and a portion of the ilium were removed en bloc. Before the instrumentation was placed, the caudad part of the body was translocated two inches (5.1 centimeters) cephalad and the iliac wings were brought closer together. Lumbopelvic stabilization was achieved with use of the Galveston technique with transpedicular fixation bilaterally at the third, fourth, and fifth lumbar levels (Figs. 5-A and 5-B). This stabilization was supplemented with a ten-hole (4.5-millimeter) pelvic reconstruction plate, with the pedicle screws at the fifth lumbar vertebra going through the plate and bicortical screws securing the plate to each iliac wing. Autogenous corticocancellous bone graft was placed from the transverse processes to the ilium bilaterally.
Postoperatively, the patient wore a molded polypropylene thoracolumbosacral orthosis that incorporated the right thigh; bed rest continued for three months. He was instructed to begin a bowel regimen of a suppository every other day; intermittent catheterization was required for bladder control. He needed bilateral ankle-foot orthoses initially, but use of the left orthosis was discontinued within the first few months after the operation. At the time of follow-up, the patient had excellent strength of all motor groups on the left except the tibialis anterior, which had good strength, and the gastrocnemius, which had poor strength. On the right, function of the tibialis anterior and the gastrocnemius was absent. All other motor groups on the right had excellent strength. There were no tumor cells at the margins of the resection, and there was 10 percent necrosis of the tumor cells in the specimen. The patient completed an additional six-month course of chemotherapy with two courses of Adriamycin (doxorubicin) (fifty milligrams per square meter of skin) and cisplatin (100 milligrams per square meter of skin); two courses of bleomycin (fifteen units per square meter of skin) and dactinomycin (1.25 milligrams per square meter of skin); two courses of methotrexate (nine grams per square meter of skin) and leucovorin (fifteen milligrams per square meter of skin); and two courses of Adriamycin (doxorubicin) (fifty milligrams per square meter of skin) and cisplatin (100 milligrams per square meter of skin). Follow-up radiographs and a computerized tomographic scan revealed a nonunion at the site of the attempted arthrodesis bilaterally eleven months postoperatively. The patient was managed with exploration and posterolateral allograft bone on June 16, 1992. Radiographs made on August 3, 1992, two months after the last procedure, demonstrated that the rods that had been inserted into the ilia showed signs of loosening. The pelvic reconstruction plate was noted to be broken bilaterally on routine follow-up radiographs (Figs. 6-A and 6-B) made on December 14, 1992; however, no additional operative intervention was advised as the patient remained asymptomatic.
At the time of the most recent follow-up, on August 3, 1998, the patient had remained disease-free for more than seven years after the initiation of therapy and walked with an ankle-foot orthosis on the right side. He had occasional low backache, which did not restrict activities or necessitate any medication. The patient had completed college and was living independently and working at two jobs (repairing computers and as a retail clerk). He was being managed with an intermittent catheterization program and was continent of stool with a bowel program consisting of a suppository every other day. Erectile function was possible with penile injections.
Osteosarcoma of the sacrum is extremely rare, and the results of treatment are found in isolated reports, most included in larger series, collected over several decades9-11,13,25,26,32,34,37,40,45,50,52. Most documented cases have been secondary to radiation therapy or have been in association with Paget disease. These secondary lesions are invasive, are prone to metastasize, and are associated with a poor prognosis. Shives et al., in a review of the experience at the Mayo Clinic from 1909 to 1980, reported that only eleven of 1122 cases of osteosarcoma arose within the sacrum and only two were primary lesions39. Of the eleven, nine were associated with previous radiation therapy and two were in patients who had Paget disease. Only two patients survived for longer than one year; one of them had been managed with a biopsy followed by radiation therapy. Fahey et al. reported on two patients, one of whom had received radiation therapy and the other of whom had been managed with an intralesional resection as well as both radiation therapy and chemotherapy13. Both patients died within twenty months after the start of treatment. Scheiden and Oberthaler presented the findings on one patient who had had postradiation osteosarcoma and had been managed with chordotomy; the patient died within one year37. In a paper by Sim et al., one patient who had received no treatment for a grade-III lesion died ten months later40. Two patients who had been managed with wide excision were reported on by Simpson et al.; one patient died in the perioperative period, whereas the other remained disease-free at thirty months41. Cases of osteosarcoma developing in patients who had Paget disease have also been described. Wu et al. reported on three siblings, two of whom had osteosarcoma52. One of these osteosarcomas was in the sacrum, and the patient died one month later of pulmonary metastases. Huvos et al. mentioned that two sacral osteosarcomas were seen at Sloan-Kettering, but the treatment and outcome were not reported26. Prognostically, malignant sacral lesions are often grouped with similar lesions occurring in the spine. Osteosarcomas of the spine, although rare, have been better reported: the median survival has been in the range of six to ten months5,14,30,39,44,45. This poor prognosis is related to the location of these lesions, which usually precludes complete resection with an adequate margin. In addition, because of the rarity of such lesions, cases have been gathered over many decades, and both operative and adjunctive therapies have evolved during this time-period. Although previous operative efforts have been palliative, recent data suggest that the combination of a more radical procedure to achieve a wide margin (spondylectomy) with chemotherapy and radiation may increase survival44. However, the literature on operative treatment of sacral tumors contains few reports on high-grade lesions, which have a high risk of metastasis. Huth et al. reported on seven patients, one of whom had a primary osteosarcoma of the sacrum25. A subtotal sacrectomy through a sacroabdominal approach was performed, but the patient died postoperatively because of sepsis. Sung et al. presented the findings on fifty-four patients who had been managed for a primary tumor of the sacrum; six of the tumors were malignant46. Although three of these patients died during the postoperative period, the other three survived at least three years. One patient who had a synovial cell sarcoma survived for longer than six years after the operative procedure. Sacrectomy may be subtotal or total, and most agree that lesions caudad to the second sacral level may be approached posteriorly8,13,15,23. Lesions cephalad to this level are most often treated with a combined approach. The first stage involves a transabdominal approach, which enables vascular control and anterior mobilization of the tumor mass. This is followed by a posterior procedure to complete the resection and to perform reconstruction. These extensive procedures often affect both pelvic stability and neural function, most notably innervation of the bowel and bladder. Studies by Gunterberg et al. demonstrated that unilateral sacral resections rarely result in serious bowel or bladder dysfunction, as innervation of the pelvic viscera is paired17,20. Preservation of the third sacral nerve root is essential to retain function in these areas; however, weak function will remain if only the second sacral nerve root is spared. Biomechanically, stability of the pelvic ring depends on the posterior osseous structures of the ilium and sacrum as well as the posterior sacroiliac ligaments. The inferior extent of these ligaments is at the level of the second sacral nerve, and partial sacrectomy caudad to this level will not affect stability. Gunterberg et al. performed a biomechanical study with use of fifteen cadaveric specimens to assess compressive loads to failure after sacral resections20. With a resection between the first and second sacral levels, load to failure decreased 30 percent compared with that in controls, and with a resection through the first sacral body, load to failure decreased 50 percent compared with that in controls. The conclusion was that resection involving more than 50 percent of the sacroiliac joint renders the pelvis unstable. Clinically, patients in whom at least one-half of the first sacral body has been preserved have not demonstrated instability6,8,23,42,43. However, total sacrectomy results in complete dissociation of the spine from the pelvis. It seems that reconstruction would be desirable, and in fact most authors8,23,42,48 have recommended this, but contrary views have been expressed in the literature. Edwards described two patients in whom a terminal resection of the spine was performed for the treatment of a tumor12. Reconstruction was not done, and the patients were kept on a rotating bed for three months to achieve gradual shortening. Edwards believed that axial stability was achieved through the muscles and through scar formation, which acted as a sling. The patients were allowed to stand with use of a brace to provide support and to limit the development of kyphosis, and they were able to function well and to walk without pain. There has also been a report of a patient who had an asymptomatic, stable pseudarthrosis following sacrectomy and fixation with Steinmann pins connected to Cotrel-Dubousset rods without bone-grafting47. Reconstruction after sacrectomy is quite challenging given the magnitude of load transmitted through this region, and it typically involves combining spinal instrumentation with a variety of implants in order to link the spine to the ilia. These implants have included sacral bars, dynamic compression plates, Steinmann pins, dynamic hip screws, and double cobra plates6,16,28,29,33,36,38,47,48. Tomita and Tsuchiya achieved pelvic fixation with two or three sacral bars or AO plates, and Harrington or Cotrel-Dubousset rods were attached to the sacral bars to complete the construct48. For one patient, a portion of the sacrum was autoclaved and reinserted as an autogenous graft. After the operation, all three patients in that study were able to walk with a walker, and union was reported in one of them. Shikata et al. inserted a sacral bar through the body of the fifth lumbar vertebra and both iliac bones and reinforced this construct more caudally with another bar, which was connected to Harrington rods38. In a second patient, this construct was augmented with wiring across the posterior iliac wings. Both patients had union and were able to walk with a cane later. Santi et al. used two large Steinmann pins through the fifth lumbar body and both iliac wings, and these were connected to rods fixed to the fourth lumbar vertebra by hooks36. Union was achieved. Blatter et al. used dynamic hip screws implanted within the iliac wings with the plates overlapping6. An internal spine fixator was connected to the plates and then to Schanz pedicle screws in the lumbar spine. The use of the Galveston technique1-3 in this setting has not been reported, to our knowledge. The mechanical advantages of this construct include a long lever arm and an increased area of loading. Mechanical testing has validated the rigidity of this construct in flexion and extension21. In summary, primary osteosarcoma of the sacrum is an extremely rare tumor that occurs in an anatomical location that makes adherence to standard oncological principles difficult. Total sacrectomy has been used successfully in the treatment of benign, extracapsular, destructive lesions and low-grade malignant lesions. With increased survival due to improvements in the medical treatment of osteosarcoma, an operative approach involving more extensive resection of high-grade sacral lesions may be warranted in the future to improve local control. Because of the rarity of such lesions, this will be difficult to prove. It is not clear from the available data that achieving fusion across the lumbosacral junction is a prerequisite for a successful functional outcome.
*No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. No funds were received in support of this study.
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