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PubMed1999

Morphologic limitations of posterior decompression by midsagittal splitting method for myelopathy caused by ossification of the posterior longitudinal ligament in the cervical spine.

STUDY DESIGN: This is a retrospective study of the morphologic limitations of posterior decompression for ossification of the posterior longitudinal ligament in the cervical spine. OBJECTIVES: To determine the morphologic limitations of the posterior approach in the management of ossification of the posterior longitudinal ligament. SUMMARY OF BACKGROUND DATA: Thirty-eight patients who underwent laminoplasty by midsagittal splitting for ossification of the posterior longitudinal ligament were reviewed. Fifteen patients were included in the noncontact group, in which the spinal cord was free of the ossified lesion after posterior decompression. Twenty-three patients were included in the contact group, in which the spinal cord was not free of the ossified lesion even after posterior decompression. METHODS: The preoperative sagittal alignment of the cervical spine and preoperative maximal thickness of ossification were compared between the two groups. In addition, the morphologic limitations of posterior decompression for ossification of the posterior longitudinal ligament were investigated. RESULTS: The following factors were found to contribute significantly to contact between the spinal cord and ossification of the posterior longitudinal ligament after posterior decompression: 1) lordosis of less than 10 degrees or kyphosis in the preoperative sagittal alignment, and 2) preoperative maximal thickness of ossification of more than 7 mm. CONCLUSIONS: Patients who exhibit significant risk factors for continued contact of the spinal cord should be morphologically considered for anterior decompression.

Adult↗
PubMed2001

Hypertrophy of the posterior longitudinal ligament is a prodromal condition to ossification: a cervical myelopathy case report.

STUDY DESIGN: A histopathologic examination of a specimen that showed hypertrophy of the posterior longitudinal ligament of the cervical spine. OBJECTIVES: To illustrate the possibility of hypertrophy of the posterior longitudinal ligament as a prodromal condition to ossification of the posterior longitudinal ligament. SUMMARY OF BACKGROUND DATA: Despite much study, the pathology of ossification of the posterior longitudinal ligament still remains unclear. Hypertrophic change often is seen in the part of the ossified ligament; however, there have been few histopathologic reports on hypertrophy of the posterior longitudinal ligament. Some reports have suggested that hypertrophy of the posterior longitudinal ligament is a prodrome of ossification of the posterior longitudinal ligament. METHODS: A 64-year-old man was admitted to the hospital because of gait disturbance and developed oliguria. In a plain radiograph, segmental ossification of the posterior longitudinal ligament was found at C4, C5, and C6. Computed tomograph myelogram revealed a soft tissue shadow, maximum 3.8 mm in diameter, on the dorsal side of the ossification of the posterior longitudinal ligament at C5 and C6. Magnetic resonance T1-weighted image (T1WI) showed an equivalent signal with the intervertebral disc on the dorsal side of ossification of the posterior longitudinal ligament. This lesion was enhanced with Gd-DTPA and confirmed as hypertrophy of the posterior longitudinal ligament. Cervical anterior decompression and fusion were performed using Yamaura's technique. The ossified and thickened lesion was elevated and removed en bloc. Then, hematoxylin-eosin and toluidine blue staining was performed to detect metachromasia. RESULTS: Macroscopic examination of the specimen revealed that soft tissue formation was connected with the C4-C5 intervertebral space and extended downward to C6-C7. Histopatholgically, collagen fibers were proliferating in the long-axis direction on both ventral and dorsal sides. This was surrounded by extended nucleus pulposus-like chondrocyte tissue, where endplate cartilage was detected around the C4 pedicle. Roux staining was low, and partial vascular and cellular infiltration was observed, although it was not marked. CONCLUSION: The herniated nucleus pulposus involving endplate cartilage from C4-C5 was limited to the superficial layer, and proliferation of nucleus pulposus-like chondrocytes occurred in the herniated tissue, where they might undergo a change in cell phenotype. The results of the present study support the hypothesis that hypertrophy of the posterior longitudinal ligament is a prodromal condition to ossification of the posterior longitudinal ligament.

Cervical Vertebrae↗
PubMed2003

Isolated vestibular ossification after meningitis associated with sensorineural hearing loss.

OBJECTIVE: Sensorineural hearing loss after bacterial meningitis is common. It is thought to be secondary to cochlear inflammation from direct bacterial seeding through the cochlear aqueduct. Although cochlear ossification with or without vestibular involvement is common, isolated vestibular ossification is rare. We review our recent experience with isolated vestibular ossification associated with profound sensorineural hearing loss and the implication for cochlear implantation in this population. STUDY DESIGN: Retrospective case review. SETTING: Academic tertiary referral center. PATIENTS: Patients referred with profound sensorineural hearing loss after bacterial meningitis with evidence of ossified vestibular labyrinth but normal cochleae on computed tomographic scanning were included in the study. INTERVENTIONS We review the history, imaging findings, operative intervention, and operative findings in this series of patients. MAIN OUTCOME MEASURES Clinical history, imaging findings, operative intervention, and operative findings. RESULTS: Three patients with isolated vestibular ossification without computed tomographic evidence of cochlear osteoneogenesis were identified. Two of these patients subsequently underwent cochlear implantation with the Clarion device with complete insertion of the electrode array. Intraoperatively, one patient had isolated scala tympani ossification and the implant electrode array was placed within the scala vestibuli. CONCLUSION: A pattern of sensorineural hearing loss and isolated ossification of the vestibular system without radiographic evidence of cochlear involvement may be seen after bacterial meningitis. In these patients, magnetic resonance imaging scanning should be performed, because computed tomographic scanning may not always detect cochlear ossification. Cochlear implantation is feasible in these patients.

Adult↗
PubMed2003

Significance of bone formation markers in patients with ossification of the posterior longitudinal ligament of the spine.

STUDY DESIGN: Serum concentrations of bone formation markers were correlated with the type, location, and progression of ossification of the posterior longitudinal ligament. OBJECTIVE: To determine the relation between bone formation markers and ossification of the posterior longitudinal ligament. SUMMARY OF BACKGROUND DATA: Few reports have correlated bone formation markers with ossification of the posterior longitudinal ligament. METHODS: In this study, 43 patients with cervical ossification of the posterior longitudinal ligament and myelopathy underwent laminoplasty. The patients were observed for more than 10 years, after which plain radiographs and tomograms of the cervical region were taken. The radiographs were selectively performed to address thoracic and lumbar ossification of the posterior longitudinal ligament. Serum concentrations of bone formation markers (intact osteocalcin, osteocalcin, carboxyterminal propeptide of human type 1 procollagen, and bone-specific alkaline phosphatase) were measured and correlated with these radiographic studies. RESULTS: A positive correlation was observed between intact osteocalcin, osteocalcin, and carboxyterminal propeptide of human type 1 procollagen in patients with combinations of cervical, thoracic, or lumbar ossification of the posterior longitudinal ligament. CONCLUSIONS: Serum concentrations of intact osteocalcin, osteocalcin, and carboxyterminal propeptide of human type 1 procollagen may reflect the activity of general ectopic bone formation in patients with ossification of the posterior longitudinal ligament.

Aged↗
PubMedDate not supplied

Heterotopic ossification after hip and spine surgery in children with cerebral palsy.

We made a retrospective review of 198 children with cerebral spasticity to determine development of heterotopic ossification. Of 61 children undergoing hip adduction lengthening, 21 had mild to moderate grades of heterotopic ossification. Only two of 132 patients who underwent spine fusions had developed heterotopic ossification, but in both it was severe, resulting in hip fusion. Two of five patients undergoing concomitant hip surgery and spine fusion developed heterotopic ossification of severe degree. The occurrence of heterotopic ossification after hip muscle surgery in children with cerebral spasticity is common but usually minor. Heterotopic ossification developing after spine fusion is rare but severe when it occurs, and concomitant hip and spine surgery causes frequent severe occurrences of heterotopic ossification.

Adolescent↗
PubMed1980

Pathological studies on the ossification of the posterior longitudinal ligament (opll).

Ossification of the posterior longitudinal ligament (OPLL), which causes marked spinal cord compression, occurs more frequently in Japan than in other parts of the world. To investigate the mechanism of this ossification, we examined two cases of mixed type of OPLL inducing severe neurological signs due to spinal cord compression and three cases of segmental OPLL type without neurological signs. Ossification of the ligament begins at the upper end of posterior margin of the vertebral body and distends mainly downward along the posterior longitudinal ligament (PLL) and finally replaces the PLL completely. Ossification consists of compact bones with lamellar structures. In the upper end of the posterior margin of the vertebral body, where the PLL fuses with the cortical bone of vertebral body, ossification always has a direct contact with cortical bone and in this portion proliferation of cartilaginous tissue and calcification were observed. Proliferation of cartilaginous tissue plays a key role in the formation of OPLL and occurs mainly by an enchondral ossification. In three among twenty one cases of cervical vertebrae examined as the control, small foci of ossification were observed which might be related to the initial phase of OPLL. Spinal cords of case 1 and 2 showed marked indentation and flattening with the loss of nerve cells, severe fibrous gliosis of the gray matter and demyelination of the anterior column. Venous congestion due to compression and vulnerability of gray matter to anoxia is important for the histological changes of spinal cord.

Adult↗
PubMed1993

Radiographic evaluation of ossification of the collateral cartilages of the third phalanx in Finnhorses.

Of 462 Finnhorses (age 1-20 years) evaluated and graded (scale 0-5) radiographically for ossification of the collateral cartilages of the 3rd phalanx of the front feet, 22.9% were totally free from sidebones (Grade 0), and 49.1% had minimal or mild ossification (Grade 1 or 2) at the base of 1 or more of the cartilages. Moderate ossification (Grade 3) was present in 10.2% of the horses, whereas ossification was advanced (Grade 4) or extensive (Grade 5) in 17.8%. In most horses > 1 cartilage was affected and 7.6% of the horses had separate centres of ossification in 1 or more of the cartilages. Large sidebones and separate centres of ossification were more common in females than in males (P < 0.001). The incidence of large sidebones was lower in young females (1-3 years) than in mares 4-6 years of age (P < 0.05), but did not increase significantly with age when young horses, 4-6 years of age, were compared with older ones. Grade 4 and 5 sidebones as well as separate centres of ossification were more common in the lateral than in the medial cartilage (P < 0.001), but no difference was observed in this respect between the front feet.

Age Factors↗
PubMed1996

Heterotopic ossification of midline abdominal incisions: CT and MR imaging findings.

OBJECTIVE: Heterotopic ossification of a midline surgical incision in a form of myositis ossificans traumatica in which osseous, cartilaginous, and, occasionally, myelogenous elements develop within an abdominal wound. When large amounts of internal ossification are present, the scar may demonstrate a complex radiologic appearance and potentially may be misinterpreted as a retained foreign body or incisional neoplastic recurrence. This report describes the CT and MR imaging findings of this entity. SUBJECTS AND METHODS: The authors retrospectively reviewed the cross-sectional imaging findings of 11 patients with ossified midline abdominal wounds. All but one of the patients were men, and the median age at diagnosis was 40 years old (range, 20-76 years old). Initial imaging was performed 7 days to 36 months after surgery (mean, 6.7 months). CT and MR imaging scans were reviewed, and lesion size, location, distance from the xiphoid, shape, and stability were assessed. Pathologic proof was obtained in one patient. RESULTS: CT and MR imaging examination in all patients showed ossified surgical scars, with the attenuation or signal intensity of the ossified components equivalent to that of the spine. Intralesional, fat-density components suggestive of marrow were present in two patients. All scars were located in the upper abdomen between the anterior abdominal fascia and the peritoneal surface, at the level of or inferior to the xiphoid process. Scars ranged in length from 0.7 to 13.4 cm (mean, 6.9 cm). Distances from the inferior tip of the xiphoid to the superior aspect of the ossified scar ranged from 0 to 4.9 cm (mean, 2.2 cm). Time from surgery to the initial postoperative demonstration of scar ossification ranged from 11 days to 36 months (mean, 6.8 months). None of the five patients who underwent preoperative CT examinations had abnormalities in the location of subsequent scar ossification. Of the nine patients with multiple postoperative examinations, scar size and appearance remained stable in six. In the remaining three patients, scar size was stable but showed progressive internal ossification. CONCLUSION: Heterotopic ossification within midline abdominal scars can be diagnosed by both CT and MR imaging examination. Recognition of the imaging appearances of such ossification should help prevent diagnostic confusion when attending postoperative patients.

Abdominal Muscles↗
PubMed1986

Indomethacin for prevention of ectopic ossification after hip arthroplasty.

Twelve patients at risk of developing postoperative para-articular ossifications were treated with indomethacin. Ossification after previous total hip arthroplasty was excised in eight patients. Four patients had ossification in the opposite hip after previous arthroplasty. Five patients in whom ectopic ossification was excised developed recurrences of lesser degree than the primary ossifications. One patient with the condition in the opposite hip developed ossification. No patients complained of stiffness in the hip and all had markedly increased hip motion. Indomethacin seems to be valuable as prophylaxis in patients at risk of developing ectopic ossification and as a supplement to secondary excision.

Aged↗
PubMed1993

Ectopic ossification in hip arthroplasty. A retrospective study of predisposing factors in 637 cases.

We investigated predisposing factors for the development of heterotopic ossification in a retrospective study of 637 hip arthroplasties, of which 484 were unilateral, 62 bilateral and 29 revision operations. The frequency of heterotopic ossification after a primary hip arthroplasty was 57 percent. In a univariate analysis, men, patients with hypertrophic arthrosis, and cemented arthroplasty were all at risk of developing heterotopic ossification. After a multivariate analysis, the male sex and the cemented arthroplasty remained as significant factors. In bilateral operations, the contralateral side developed heterotopic ossification in 82 percent when the primary hip operation had already caused ossification. There was no increase in ossifications after the contralateral operation. Half of the revision operations had an increase of heterotopic ossification from 1 to 4 Brooker classes.

Adult↗
PubMed1991

Ossification of the N-methyl-N'-nitro-N-nitrosoguanidine-induced small intestine adenocarcinomas in rats.

Eighty rats out of 233 developed malignant tumors in the stomach and small intestine by administration of 100 micrograms/ml N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) in drinking water for 28 weeks. Fifteen lesions (30%) among the 50 small intestinal carcinomas showed ossification in the tumor, while none in the sarcomas (12 lesions) or gastric adenocarcinomas (59 lesions) showed ossification. Multifocal heterotopic bone formation was found within stroma in close approximation to the neoplastic glands. The islands of bone trabeculae were covered by osteoblast-like cells, and abundant fibroblasts in loose stroma gathered around the bony islands which enclosed osteocytes in lacunae. Neither osteoclast nor cartilage was identified. In 5 cases, ossification was extensive, which comprised the major portion of the stroma. In contrast, intraluminal calcification without ossified foci were occasionally seen in the gastric carcinoma. Ossification of the intestinal tumors correlated to the degree of mucin content (p < 0.05, chi square with Yates' correction), degree of neutrophilic infiltration (p < 0.05), and size of the tumor (p < 0.1). (The average size of the ossified tumor was 21.5 +/- 4.0 mm, while that of nonossified tumors was 12.5 +/- 1.9 mm). The degree of tumoral necrosis, desmoplasia or depth of invasion did not seem to be related to the ossification of the tumor. The ossification rate of this experimental model was much higher than in human cases. Various histologic alterations, such as mucin leakage, inflammatory cell infiltration, necrosis and/or fibrosis, which might be caused by continuous stimulation of the strong carcinogen, may play some role in the ossification of experimental tumors.

Adenocarcinoma↗
PubMed2000

Heterotopic ossification in total hip arthroplasty: the significance for clinical outcome.

This study evaluates 706 patients with 835 primary total hip replacements documented in a prospective fashion in a multicenter study with respect to correlation between heterotopic ossification (HO) and clinical outcome. Only patients without prophylaxis against HO entered the study. The mean clinical and radiological follow-up was 3.1 years (+/- 0.7). Heterotopic ossification was noted in 47% of all total hips replaced. It was graded as mild (Brooker I) in 29.1%, moderate (Brooker II) in 12.7%, and severe (Brooker III and IV) in 5.2%. All clinical parameters investigated were significantly affected with the increasing amount of heterotopic ossification. The strongest correlation was found in flexion range and spreading distance. Both factors were significantly decreased with higher degrees of ossification. The other clinical parameters investigated, walking capacity, limp, and use of analgesics, were altered to a lesser extent and only with higher degrees of heterotopic bone formation. Finally, patient satisfaction was significantly influenced by the degree of heterotopic ossification and dropped from almost 90% good or excellent patient satisfaction in the non-ossification group to less than 30% in the group with severe ossification.

Aged↗
PubMed1998

Heterotopic ossification of the hip after spinal cord injury.

OBJECTIVE: To analyse the risk factors of heterotopic ossification after spinal cord injury. METHODS: Of 104 patients with spinal cord injury, 47 (45.2%) were complicated by heterotopic ossification of the hip. These patients with heterotopic ossification were compared with 57 patients without heterotopic ossification. RESULTS: Statistical analysis showed that complete paraplegia, spasticity and pressure sore were significantly (P < 0.05) or highly significantly (P < 0.01) related to heterotopic ossification formation. The coexistence of two or three of these factors in the paraplegic patients was found to significantly (P < 0.01) enhance the risk of heterotopic ossification formation. CONCLUSION: When the spinal cord injured patients have single or multiple risk factors, they should be predicted for susceptibility of heterotopic ossification.

Adult↗
PubMed2005

Colchicine inhibits heterotopic ossification: experimental study in rabbits.

BACKGROUND: Heterotopic ossification is a common complication of hip surgery and musculoskeletal or brain trauma. OBJECTIVES: To confirm by in vivo study that colchicine inhibits osteoblast cell proliferation with marked decrease in tissue mineralization. METHODS: Heterotopic ossification was induced in three groups of New Zealand white rabbits (females, 6 months old, weight 3-3.5 kg) by injecting 2 ml bone marrow drawn from the iliac crest into their right thigh muscle. To prevent heterotopic ossification, colchicine (0.25 mg/ day) was administered orally for 4 weeks to two groups of adult rabbits: group A (preload group)--1 week preceding bone marrow injection; group B--on day of injection; and group C--control group. RESULTS: After 4 weeks the rabbits were evaluated by radiographs and ultrasound for evidence of heterotopic ossification. At the end of the study histologic samples were taken from all the thighs. Imaging and histologic studies showed, with statistical significance, almost complete prevention of heterotopic ossification formation in group A (preload) and a marked decrease in group B, when compared with the controls where large new bone had formed at the injection site. These results indicated the inhibitory effects of colchicine on a bone-forming process in soft tissue such as heterotopic ossification. CONCLUSIONS: The role of colchicine in preventing heterotopic ossification in other bone-forming conditions, such as hip arthroplasty or pelvic trauma, and after brain trauma, remains to be evaluated in a clinical setting.

Animals↗
PubMed2006

[Relationship between the central nervous system injury and the heterotopic ossification].

OBJECTIVE: To review the progress of the research on the relationship between the central nervous system injury and the heterotopic ossification. METHODS: The recent articles on the central nervous system injury and the heterotopic ossification were extensively reviewed, and the related clinical signs, symptoms, pathogenesis diagnosis, risk factors, prophylaxis, and treatment of the neurogenic heterotopic ossification were investigated. RESULTS: The possible mechanism for the neurogenic heterotopic ossification might involve the roles of the bone morphogenetic protein and the basic fibroblast growth factor, which were suggested as mediators in differentiation of the progenitor cells. Sonographic, serum creatine phosphokinase, and C-reactive protein were recommended as the useful screening tools for heterotopic ossification. Colchicine and rofecoxib could be used for the prophylaxis or treatment of heterotopic ossification. CONCLUSION: The research on the neurogenic heterotopic ossification has achieved a great development but further studies in this field are still required.

Humans↗
PubMed1990

Heterotopic ossification about the hip after intramedullary nailing for fractures of the femur.

A prospective study of 100 consecutive unilateral fractures of the shaft of the femur was performed to delineate the incidence of, and the factors predisposing to, heterotopic ossification about the hip after intramedullary nailing. Bone debris from reaming of the endosteal canal is deposited in the soft tissues surrounding the site of insertion of the nail, and we postulated that this debris may stimulate the formation of heterotopic bone and that decreasing the amount of debris left in the tissues after nailing may decrease the amount of heterotopic ossification. To test this theory, the patients were treated with routine intramedullary nailing and were randomly divided into two groups. In Group I, the operative incision was irrigated with 250 milliliters of normal saline solution with use of a bulb syringe before the wound was closed, and in Group II, the incision was irrigated with 3000 milliliters of normal saline solution with use of pulsatile lavage. The two groups were similar in all other respects. Eighty patients (eighty fractures; forty in Group I and forty in Group II) were available for follow-up and were evaluated in a blind fashion after the fracture had united. A grading system that was based on the length of the heterotopic ossification, as measured on antero-posterior radiographs of the hip, was used. In thirty-two of the patients (40 per cent), no heterotopic ossification developed, whereas minimum or mild ossification developed in twenty-seven patients (34 per cent). Moderate ossification developed in twelve patients (15 per cent) and severe ossification, in nine patients (11 per cent).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1983

[Histopathological study of aging of the posterior portion of human cervical vertebral bodies and discs--with special reference to the early ossification of the posterior longitudinal ligament].

UNLABELLED: Ossification of the posterior longitudinal ligament ( OPLL ) of the cervical spine is a disease causing spinal canal stenosis and, henceforth , spinal cord compression. This ossification is found approximately in three percent of the adult Japanese, but it is also found to be present among Chinese, Korean and other South-East Asians, whereas the incidence among Caucasians was reported to be significantly low. The etiology of this interesting ossification is still unknown although multidisciplinary studies have been carried out in Japan in recent years. The purpose of the present study is to find an early ossification of the posterior longitudinal ligament of the cervical spine and to see its relationship with other chronological changes of the surrounding structures. MATERIAL AND METHOD: One hundred and forty-one cervical spinal columns were obtained en bloc from C2 to C7 from the autopsied bodies at Juntendo University Hospital and at the Tokyo Metropolitan Medical Examiners' Office. There were 89 males and 52 females with a wide age distribution. A 66 year-old male case with advanced continuous OPLL died at Juntendo University Hospital was added to the study. The specimens were either cross-sectioned or sagittally sectioned, and studied soft-ray-roentgenologically and histopathologically. RESULTS: There were specimens after the third decade of life showing micro-ossification along the midline of the posterior aspect of the vertebral body on cross-section as well as micro-ossification or hyperostosis adjacent to the posterior corner of the vertebral body on sagittal section. These micro-ossification or hyperostosis seemed to be a product of a physiological aging process, but could be considered as a precursor of the OPLL . The periosteum was well demonstrated on the posterior aspect of the vertebral body in the first two decades of life, but it became inconspicuous with age. In the adult spine there was no clear delineation between the deep layer of the posterior longitudinal ligament and the fibrous layer of the periosteum . The cambium layer looked absent on hematoxylin-eosin stain. However, on Giemsa stain there appeared a thin layer which would present increased cellular activity between the body and what appeared to be the fibrous layer of the periosteal. This layer was considered to be a 'sleeping cambium layer' for which it was named 'latent periostium layer (LPL)'.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1996

[Postoperative radiotherapy in the prevention of heterotopic ossification after endoprosthetic hip joint replacement].

BACKGROUND: Following total hip arthroplasty high-grade heterotopic ossification occurs with a range of 0.5 to 27%. Local postoperative hip irradiation using different dosage and fractionation schedules reduces the incidence in high-risk cases on an average of 8%. The present retrospective study compares results after conventionally fractionated and high-dose radiotherapy. PATIENTS AND METHOD: A total of 50 hips (46 patients) from 2 different risk groups had complete follow-up. In group I (40 hips [80.0%]) radiotherapy was indicated after surgical excision of pre-existing high-grade heterotopic ossification, in group II (10 hips [20.0%]) for several risk factors (contralateral heterotopic ossification [n = 7], hypertrophic osteoarthritis [n = 2], spondylosis hyperostotica [n = 1]). In 28/50 cases (56.0%) conventionally fractionated irradiation with total doses ranging from 12.0 to 20.0 Gy was given, in 22/50 hips (44.0%) a high-dose irradiation consisting of 10.0 Gy given in 2 fractions on each of the first 2 postoperative days was applied. After a minimal observation period of 6 months (median: 22 months, range: 6 to 56 months) roentgenograms were analysed using a modified Brooker score. RESULTS: At follow-up, 2 hips in group I had recurrence of high-grade heterotopic ossification with the stages IIIA and IVB. In 1 case radiotherapy was interrupted after 3 x 2.0 Gy due to sepsis (IIIA), in the other case ectopic bone recurred from bony islands which layed outside the radiation portal (IVB). In group II, 9 patients had stage 0 and 1 patient stage IA. Statistical analysis using the Wilcoxon test showed a highly significant reduction of the amount of pre-existing heterotopic ossification (p < 0.0001) for both fractionation schedules. The comparison of both fractionation groups with the Whitney-Mann-U-test (p = 0.92) showed no statistical significant difference. CONCLUSIONS: The data about the high therapeutic efficacy of postoperative radiotherapy for prevention of heterotopic ossification were confirmed. Both fractionation schedules led to a sufficient reduction of high-grade heterotopic ossification in the 2 treated risk groups.

Adult↗