Using Anatomic Landmarks to Locate Schöttle's Point Was Accurate Without Fluoroscopy During Medial Patellofemoral Ligament Reconstruction.

PURPOSE: The purpose of the present study was to analyze the anatomic landmarks of Schöttle's point and establish a locating method for identification. METHODS: From 2013 to 2016, patients undergoing medial patellofemoral ligament (MPFL) reconstruction for patellofemoral instability were enrolled. INCLUSION CRITERIA: at least 2 episodes of patellar dislocation. EXCLUSION CRITERIA: previous knee surgeries, open physes, severe trochlear dysplasia， tibial tuberosity lateralization, or patella alta. Group A: From January 2013 to December 2013, preoperative 3-dimensional computed tomography (3D-CT) images were obtained. Anatomic features of Schöttle's point were measured on the 3D-CT images. A Schöttle's point locating method with 2 distinct landmarks was established. Group B: From January 2014 to January 2016, consecutive MPFL reconstructions were performed. The placement of Schöttle's point was following the established method without fluoroscopy. The accuracy of femoral tunnel positions was assessed on the 3D-CT images postoperatively. RESULTS: CT images of 53 knees were obtained in group A. Forty-seven MPFL reconstructions were performed in group B. No significant difference was found between the 2 groups regarding to demographic characteristics. The intraclass correlation coefficients were excellent for all measures (r = 0.97). In group A, Schöttle's point was 8.1 ± 0.2 mm (95% confidence interval [CI], 7.7-8.5) distal to the apex of the adductor tubercle and 8.0 ± 0.3 mm (95% CI, 7.4-8.6) anterior to the posterior edge. Apex of the adductor tubercle was defined as the most convex point, and posterior edge was defined as the edge of the posteromedial cortex in the transition area between the medial condyle and femoral shaft. In group B, 44 of 47 femoral tunnels (93.6%) were considered localized in the proper zone. CONCLUSIONS: Schöttle's point was approximately 8 mm distal to the apex of the adductor tubercle and 8 mm from the posterior edge. Schöttle's point locating method without fluoroscopy had high accuracy. LEVEL OF EVIDENCE: Level IV, case series.

18F-fluorodeoxyglucose positron emission tomography/computed tomography in the evaluation of spinal giant cell tumors.

OBJECTIVE: To investigate the value of 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) in the evaluation of spinal giant cell tumors (GCTs). MATERIALS AND METHODS: The PET/CT and clinical data of 16 patients with spinal GCTs were reviewed. The maximal standardized uptake value (SUVmax), longest diameter, and CT features of spinal GCTs were analyzed. The value of PET/CT and MRI in displaying the recurrent lesions was compared. PET Response Criteria in Solid Tumors were adopted to evaluate the response to radiotherapy. RESULTS: Data from 7 males and 9 females (median age 32.5 years) were analyzed. Eight patients had primary GCTs with a median SUVmax of 11.91 and a median length of 4.42 cm. Eight patients had relapsed GCTs with a median SUVmax of 10.34 and a median length of 6.23 cm. There was no statistical difference between the SUVmax of primary and relapsed GCTs. The SUVmax did not correlate with length. In 8 relapsed patients, 4 lesions invaded the vertebral canal, but 2 of which were not displayed on MRI. Metal prostheses showed extremely low signal intensity on MRI, even in the 3 cases with increased intra-prosthetic 18F-FDG concentration. Five relapsed patients with subsequent radiotherapy had a repeat PET/CT. A complete, partial, and stable metabolic response was observed in 1, 3, and 1 patient, respectively. CONCLUSIONS: Both the primary and recurrent spinal GCTs avidly accumulate 18F-FDG. For recurrent GCTs, PET/CT may provide incremental value in the assessment of the vertebral canal and intra-prosthetic involvement and the response to radiotherapy.

The Role of Radiotherapy and Surgery in the Management of Aggressive Vertebral Hemangioma: A Retrospective Study of 20 Patients.

BACKGROUND Vertebral hemangioma is usually a benign and asymptomatic tumor of blood vessels, but can be aggressive (symptomatic) with expansion, pain, and spinal cord compression. The aim of this study was to review the effects of radiotherapy, surgery, and other treatment approaches in patients with aggressive vertebral hemangioma. MATERIAL AND METHODS Retrospective clinical review included 20 patients who underwent radiotherapy as their first-line treatment for aggressive vertebral hemangioma with mild or slowly developing neurological deficit. External radiation was divided into 20-25 fractions with a total dose of 40-50 Gy. Minimum clinical follow-up after treatment was 20 months. RESULTS The 20 patients included eight men and 12 women (mean age, 46.6 years), with aggressive vertebral hemangioma located in the cervical, thoracic, and lumbar vertebrae in four, 14, and two patients, respectively. Following radiotherapy treatment, 65.0% of patients (13/20) were symptom-free, without recurrence or malignant transformation at the time of last clinical follow-up (average, 75.2 months). Due to minor post-radiation vertebral re-ossification, two of the 13 patients who were initially symptom-free after radiotherapy requested percutaneous vertebroplasty. A further seven patients required surgery after radiotherapy, due to increasing neurological deficit in three patients, and persistent neurological deficit in four patients. At the last follow-up (average, 63.6 months), six patients were symptom-free, and one patient still had slight residual symptoms. CONCLUSIONS Radiotherapy was a safe and effective treatment choice for aggressive vertebral hemangioma, but in case with severe spinal cord compression and neurological deficit, surgical intervention was required.

A fetal rat model of ventricular noncompaction caused by intrauterine hyperglycemia.

BACKGROUND: This study aims to develop a fetal rat model of ventricular noncompaction (NVM) using streptozotocin (STZ)-induced gestational hyperglycemia and compare it with a retinoic acid (RA) model. METHODS: Female SD rats were categorized into STZ, RA, and normal control (NC) groups. The STZ group was given a high-fat diet pre-pregnancy and 35 mg/kg of 2% STZ postpregnancy. The RA group received a 90 mg/kg dose of RA on day 13 postpregnancy. Embryonic myocardial morphology was analyzed through HE staining, and embryonic cardiomyocyte ultrastructures were studied using electron microscopy. Diagnoses of NVM were based on a ratio of noncompact myocardium (N) to compact myocardium (C) >1.4, accompanied by thick myocardial trabeculae and a thin myocardial compaction layer. Kruskal-Wallis test determined N/C ratio differences among groups. RESULTS: Both STZ and RA groups displayed significant NVM characteristics. The left ventricular (LV) N/C in the STZ, RA, and NC groups were 1.983 (1.423-3.527), 1.640 (1.197-2.895), and 0.927 (0.806-1.087), respectively, with a statistically significant difference (P<0.001). The right ventricular (RV) N/C in the STZ, RA, and NC groups were 2.097 (1.364-3.081), 1.897 (1.337-2.662), and 0.869 (0.732-1.022), respectively, with a significant difference (P<0.001). Electron microscopy highlighted marked endoplasmic reticulum swelling in embryonic cardiomyocytes from both STZ and RA groups. CONCLUSION: Our model underscores the pivotal role of an adverse intrauterine developmental environment in the onset of NVM. This insight holds significant implications for future studies exploring the pathogenesis of NVM.

Clinical features and pathogenesis of scoliosis due to spinal astrocytoma.

The aetiology of scoliosis remains unclear. Some studies have focused on the theory of possible muscular imbalance. The role of the spinal cord, which directly innervates the paraspinal muscles, in muscular imbalance has not yet been studied. Spinal astrocytomas often grow on one side of the spinal cord, destroying it asymmetrically. Asymmetrical damage to the spinal cord can lead to asymmetrical changes in paraspinal muscles. The present study investigated the effect of muscular imbalance on scoliosis by observing scoliosis caused by spinal astrocytomas. Patients diagnosed with spinal astrocytomas in a single centre were analysed, and the type and side of the symptoms, sagittal tumour position, scoliosis, end vertebrae and apical vertebrae of scoliosis were recorded. The tumour side was assumed from symptom type and side, and the cross-sectional area of the paraspinal muscles on both sides of the end vertebra was outlined and compared. The incidence of astrocytoma-induced scoliosis was significantly higher in patients with unilateral symptoms. The inferred tumour side was highly consistent with the convex side of scoliosis. The distal vertebral segments of scoliosis were consistent with the spinal cord segments involved in the astrocytomas. The apical vertebrae were more caudal in astrocytoma-induced scoliosis. The cross-sectional area of the multifidus muscle on the convex side of apical-level scoliosis was significantly smaller than that on the concave side. However, no significant differences were observed in the erector spinae muscles. Overall, spinal astrocytomas can cause asymmetric destruction of the corresponding spinal cord segment, resulting in asymmetric atrophy and weakness of the multifidus muscle innervated by the spinal cord segment, thereby causing scoliosis that is convex to the weaker side. This mechanism involves asymmetric lower neuron paralysis of the multifidus muscle. This is a type of scoliosis with several differences from idiopathic scoliosis.

CIC-NUTM1 Sarcomas Affecting the Spine.

CONTEXT.­: Tumors harboring CIC-NUTM1 fusion are a newly recognized rare sarcoma, but the documented cases are still limited. It is unclear whether it is the same as classic CIC-DUX4 sarcoma in terms of its clinical, pathologic, and behavioral aspects. OBJECTIVE.­: To further explore the clinicopathologic characteristics of CIC-NUTM1 sarcoma. DESIGN.­: The cases were diagnosed based on immunophenotype, next-generation sequencing, and fluorescence in situ hybridization tests and compared with the reported CIC-NUTM1 sarcomas in the literature. RESULTS.­: Three cases of CIC-NUTM1 sarcomas involving the spine in adults were described. The tumors occurred in 2 men and 1 woman, aged 38 to 61 years. Two tumors were located in thoracic vertebrae and 1 in a cervical vertebra. All were locally advanced lesions destroying the bone and soft tissues without spinal cord involvement or metastasis. The tumors were composed of monomorphic small to medium-sized cells with round to epithelioid appearance. The architecture was lobulated and solid with diffuse or multifocal myxoid stroma. Next-generation sequencing revealed an in-frame fusion between CIC (exon 16 or 17) and NUTM1 (exon 5 or 6) in 3 cases. Fluorescence in situ hybridization confirmed CIC and NUTM1 breaks, and immunohistochemistry showed NUT staining in the nucleus. The patients died of disease 8 to 15 months (mean, 10.7 months) after presentation. Of the CIC-NUTM1 sarcomas reported in the literature along with our cases (n = 11), 8 cases developed in axial bone (5 spine, 3 skull base). CONCLUSIONS.­: CIC-NUTM1 sarcomas demonstrate distinct anatomic tropism for the axial skeleton and unfavorable behavior compared with classic CIC sarcoma.

Radiologic and clinical changes after denosumab treatment for giant cell tumors of the mobile spine: a quantitative study.

OBJECTIVES: To analyze the radiologic and clinical changes after denosumab treatment in patients with giant cell tumors (GCTs) in the mobile spine. METHODS: Clinical data and images by computed tomography and magnetic resonance imaging at a single center were retrospectively reviewed before and after denosumab treatment. RESULTS: Pre- and post-treatment data from 24 patients were evaluated. On imaging, marginal ossification and/or bone formation was observed in 22 patients (91.7%). The median maximum diameter of the GCT reduced from 52.5 to 48.2 mm (p < 0.001), and the mean proportion of tumor to spinal canal area decreased from 36.8 to 18.5% (p < 0.001). Out of six patients with compression, three patients (50%) showed no compression after treatment. The signal intensity (SI) ratio between the solid part of the tumor and the normal spinal cord on T2-weighted MR images was 0.77 ± 0.22 and decreased to 0.58 ± 0.22 (p = 0.001). On clinical symptoms, the mean visual analog scale scores were reduced from 5.3 to 2.0 (p < 0.001) and the Karnofsky Performance Scale scores increased from a median of 65 to 80 (p < 0.001). Post-treatment, performance scores improved in eight patients (33.3%) (p = 0.003), and the neurological function of four patients improved according to Frankel grade (p = 0.046). CONCLUSIONS: Bone formation, tumor reduction, regression of epidural lesion and the decrease in SI ratio on T2-weighted image should be considered as the effectiveness of denosumab in the treatment of spinal GCT. In clinical application, denosumab can relieve pain, improve neurological function, and improve the quality of life of spinal GCT patients.

Imaging Features of Aggressive Giant Cell Tumors of the Mobile Spine: Retrospective Analysis of 101 Patients From Single Center.

STUDY DESIGN: Retrospective study. OBJECTIVES: Giant cell tumors (GCTs) of the mobile spine can be locally aggressive. This study described and classified the typical and atypical appearance of aggressive spinal GCTs according to imaging findings to help the imaging diagnosis, especially for patients with rapid neurological deficit that may require emergent surgery without biopsy. METHODS: Computed tomography (CT) and magnetic resonance imaging (MRI) scans of patients diagnosed with aggressive spinal GCTs at single center were reviewed. RESULTS: Overall, 101 patients with 100 CT images and 94 MR images were examined. All lesions were osteolytic with cortical destruction; 95 lesions showed epidural extension; 90 were centered in the vertebral body; 82 showed pathological fracture and/or collapse of the vertebral body; 78 had pseudotrabeculation on CT; 80 showed low-to-iso signal intensity or heterogeneous high-signal intensity with cystic areas on the T2-weighted images; 9 showed fluid-fluid level on T2-weighted images; and 61 patients showed marked enhancement on contrast-enhanced CT and/or MRI. Forty-one lesions (40.6%) had at least 1 atypical radiographic feature: 19 involved ≥2 segments; 11 were centered in the posterior neural arch; 10 had a paravertebral mass over 2 segments; 16 showed partial margin sclerosis with partial cortical destruction on CT scans; and 3 showed mineralization within the tumor on CT. Eighty-eight patients underwent CT-guided biopsy with a diagnostic accuracy rate of 94.3%. CONCLUSIONS: Spinal GCTs might appear more radiologically atypical, and about 40% of the lesions may have at least 1 atypical feature. CT-guided biopsies are recommended for definitive diagnosis.

Imaging features and atypical signs of symptomatic vertebral haemangioma: a retrospective single-centre analysis of 118 patients.

OBJECTIVES: Symptomatic vertebral haemangioma (SVH) can present with atypical imaging features. Thus, this study analysed the imaging features of SVH using CT and MRI to improve SVH awareness. METHODS: We retrospectively analysed CT and MRI characteristics of 118 patients with clinically and pathologically confirmed SVH. RESULTS: Overall, 118 patients were diagnosed with SVH, including 79 females and 39 males (mean age, 45.76 ± 16.36 years). The thoracic spine (n = 86) was the most common location of SVH, followed by the lumbar spine (n = 17). Involvement of multiple spinal segments was observed in 15 patients (12.71%). A total of 101 lesions (85.59%) were centred in the vertebral body, 15 lesions (12.71%) were centred in the posterior attachment, and two lesions (2%) were centred in the paraspinal region. CT showed 39 lesions (33.05%) without a typical honeycomb or polka-dot pattern. Compression fracture was observed in 23 patients (19.49%). Extraosseous extension was present in 111 patients (94.1%), and 17 lesions (14.41%) presented with foraminal extension. Epidural bony compression was observed in 46 patients (38.98%). 20 lesions (16.95%) had atypical T2 weighted MRI signals, and 8 lesions (10.26%) showed atypical enhancement. CONCLUSION: SVH was predominantly located in the thoracic spine. Involvement of multiple segments, posterior attachment localisation, absence of honeycomb or polka-dot signs, compression fracture, and atypical T2 weighted imaging signals and enhancement were uncommon. Epidural bony compression was not uncommon and has important clinical significance. ADVANCES IN KNOWLEDGE: The imaging features of SVHs are not fully understood. We examined the largest series of SVH cases reported to date.

Typical and Atypical Radiographic Features of Symptomatic Osteoblastoma in the Spine.

BACKGROUND: Spine osteoblastomas (OBs) are relatively rare. In contrast to osteoid osteoma, radiologic and clinical manifestations of OB can be varied and atypical. Typical radiographic features in spinal OB include peritumoral bone sclerosis, bone marrow edema, and soft tissue edema. Atypical radiographic features include lesions involving ≥3 segments, lesions with extensive (≥3 segments) bone sclerosis, excessive edema (≥3 segments) of soft tissue and bone marrow, no intralesional calcification, and location in the vertebral body only. The aim of this study was to identify typical and atypical features of OB. METHODS: Pretreatment computed tomography scans and magnetic resonance imaging were reviewed retrospectively. Percutaneous biopsies were performed to confirm pathology in atypical cases. RESULTS: A total of 50 images from patients with diagnosed OB were reviewed. Atypical radiographic features were found in 18 cases (36%). Pathologic diagnosis was confirmed as OB in 86.2% (25/29) cases after percutaneous computed tomography-guided biopsy. CONCLUSIONS: Our results show that >30% of spinal OB cases might have atypical radiographic features. In cases with atypical radiographic features, computed tomography-guided biopsies are recommended.

F18-fluorodeoxyglucose positron emission tomography/computed tomography in the evaluation of vertebral vascular tumors.

PURPOSE: The uptake of 18F-FDG is higher in most malignancies than in benign tumors. This study aimed to investigate the diagnostic value of 18F-FDG PET/CT in vertebral vascular tumors. MATERIALS AND METHODS: We retrospectively collected PET/CT and clinical data of patients with vertebral vascular tumors and analyzed the location, number, and bone destruction and FDG uptake features of the lesion. We measured SUVmax and maximum diameter and analyzed the correlations between SUVmax and the pathological results, size, and CT features. RESULTS: Twenty-one pathology-proven vertebral vascular tumors were included: 2 angiosarcomas (SUVmax, 11.6 and 32.3), 1 epithelioid hemangioendothelioma (SUVmax, 5.7), 1 epithelioid hemangioma (SUVmax, 8.5), and 17 aggressive hemangiomas. Twelve cases of typical hemangiomas were included as controls. The SUVmax and diameter of the aggressive hemangiomas were higher than those of the typical hemangiomas. The mean SUVmax of aggressive hemangiomas with cortical destruction was higher than that of those without cortical destruction (t = -2.566, P = 0.022). Radioactive distribution in aggressive hemangiomas was homogeneous and heterogeneous in nine and eight cases, respectively. In six aggressive hemangiomas, the FDG uptake of residual and marginal sclerosing bone was higher than that of the osteolytic destruction area and/or paravertebral soft tissue. Six aggressive hemangiomas involved the spinal canal, without clear visualization on PET/CT. CONCLUSION: 18F-FDG uptake of vertebral malignant vascular tumors is higher than that of hemangiomas. The FDG uptake of hemangiomas varies and may be related to concurrent cortical destruction. 18F-FDG PET/CT shows limitations in evaluating the spinal canal involvement of aggressive hemangioma.

Spinal osteoblastoma: a retrospective study of 35 patients' imaging findings with an emphasis on MRI.

OBJECTIVE: To investigate the values of multimodal imaging approaches in the diagnosis of spinal osteoblastomas with an emphasis on MRI findings. MATERIALS AND METHODS: We retrospectively evaluated the imaging findings of 35 patients with spinal osteoblastomas. The imaging methods included radiography, whole-body bone scintigraphy (WBBS), CT and MRI. RESULTS: Radiography detected 87.1% (27/31) of the lesions; WBBS demonstrated increased radionuclide activity in all the lesions. CT could precisely show and localize all niduses, and calcification was always detected. MRI usually could adequately delineate the niduses of osteoblastomas, especially on T2WI (88.2%; 30/34). 71.9% (23/32) of osteoblastomas were surrounded with moderate or extensive bone marrow edema (BME) with soft tissue edema (STE). STE always extended along the muscle bundle adjacent to the lesion; there was no subcutaneous fat involvement. BME was eccentrically distributed in the vertebral body and spread inward from the sides of the nidus. The extent of BME in the vertebral body tended to be inversely proportional to the distance from the nidus. In addition, rare magnifications of osteoblastoma including multifocal diseases (n = 2), vertebra plana (n = 1) or with aneurysmal bone cysts (n = 6) were also observed in our study. CONCLUSIONS: In patients showing moderate or extensive BME together with STE on MRI, both CT and MRI should be used to confirm nidus presence. The above-mentioned characteristics of edema on MRI of patients with spinal osteoblastoma are helpful in not only localizing the nidus, but also enhancing the diagnostic confidence.

Reossification and prognosis following radiotherapy with/without surgery for spinal solitary plasmacytoma of the bone: a retrospective study of 39 patients.

BACKGROUND CONTEXT: Solitary plasmacytoma of bone (SPB) can progress to multiple myeloma (MM). Little attention has been paid to the reossification findings on computed tomography (CT) and their correlation with prognosis after radiotherapy with/without surgery. PURPOSE: To evaluate reossification after radiotherapy and prognostic factors of spinal SPB using single-center data. STUDY DESIGN: Retrospective observational study. PATIENT SAMPLE: Patients who had spinal SPB and received radiotherapy with/without surgery, without chemotherapy, denosumab or zoledronic acid. OUTCOME MEASURES: MM progression rate, mortality rate, and reossification rate at 12 months. METHODS: This retrospective clinical review included 39 patients who underwent radiotherapy as first-line treatment for SPB in the spine. External radiation was divided into 20-25 fractions with a total dose of 35-46 Gy. At the 12-month follow-up after the index radiotherapy, significant and mild reossification, defined as bone formation with ≥30% or 0%-30% increase, respectively, in bony area based on increase in CT values were documented, along with progressive disease, which was a decrease in bony area with lesion enlargement. This study was funded by AO Foundation, AOSpine (AOSDIA2019-026) (CHF45,000), Peking University Medicine Seed Fund for Interdisciplinary Research (BMU2018MX022) (¥40,000), and Peking University Third Hospital (No. Y71508-01) (¥400,000). RESULTS: Twenty-six men and 13 women (mean age, 51.5 years) were included. Solitary plasmacytomas were located in the cervical, thoracic, and lumbar vertebrae in 16, 17, and 6 patients, respectively. The mean clinical follow-up period after treatment was 72 (range 12-216) months. Sixteen patients (41.0%) had significant reossification after radiotherapy, 21 (53.8%) showed mild reossification, and 2 (5.2%) had progressive bony destruction (after 7 and 23 months, respectively). There were no significant differences in age among the three groups (p=.127). At a mean follow-up of 37 (range 6-90) months after radiosurgery, 14 (35.8%) patients developed MM, including 9 patients who died at a mean duration of 55 (range 19-102) months. In the significant reossification group, only 1 patient (6.3%, 1 of 16) had MM progression 82 months after treatment (p=.044). In the mild reossification group, 56.5% (13 of 23) of patients had MM progression. The significant reossification rates of the radiotherapy dose groups of <40 Gy and ≥40 Gy were 35.7% and 44% (p=.614), respectively. In the univariate analysis, age ≥65 years (p<.001), tumor ≥5 cm (p=.009), Spinal Instability Neoplastic Score scores ≥11.5 (p=.040), radiotherapy (RT) combined with surgery (p<.001), and progression to MM (p=.007) were the independent prognostic factors for overall survival; whereas, age >44 years (p=.045) and RT combined with surgery (p<.001) were for multiple myeloma-free survival. In the multivariate analyses, age >65 years (p=.004) and progression to MM (p=.007) were the unfavorable independent factors for overall survival, whereas RT combined with surgery (p=.004) was the only factor for multiple myeloma-free survival. CONCLUSIONS: In patients with spinal SPB, 41.0% lesions showed significant reossification after radiotherapy. Patients with significant reossification had a better prognosis with less possibility of MM progression. Radiotherapy may be a safe and effective treatment choice for spinal SPB; more attention should be paid to reossification.

Percutaneous radiofrequency ablation versus open surgical resection for spinal osteoid osteoma.

BACKGROUND CONTEXT: Both open surgical resection (OSR) and radiofrequency ablation (RFA) have been reported for spinal osteoid osteoma (OO). PURPOSE: To verify the clinical safety and efficiency of RFA with OSR in treating spinal OO. STUDY DESIGN: Retrospective cohort study. PATIENT SAMPLE: Twenty-eight consecutive patients with spinal OO who underwent either RFA or OSR in our institute between September 2006 and December 2016. OUTCOME MEASURES: The age, gender, lesion distribution, surgical time, estimated blood loss, complications, local recurrence, visual analogue scale (VAS), and the modified Frankel grade were documented. METHODS: We retrospectively reviewed 28 patients with spinal OO who had been treated in our hospital from September 2006 to December 2016. Patients were followed at 3, 6, 12, and 24 months after the index surgery. The minimum follow-up period was 12 months. This study was funded by Peking University Third Hospital (Y71508-01) (¥ 400,000). RESULTS: Twelve and 16 patients were treated with CT-guided percutaneous RFA and OSR, respectively. Spinal OO locations were cervical in 4, thoracic in 4, lumbar in 3, and sacral vertebra in 1 in the RFA group and cervical in 12, thoracic in 1, and lumber in 3 in the OSR group. RFA showed shorter operating time, less blood loss, and less in-hospital stay than open surgery [105.0 ± 33.8 minutes vs. 186.4 ± 53.5 minutes (p < .001), 1 (0 to 5) ml vs. 125 (30-1200) ml (p < .001) and 1 (1-3) days vs. 6 (3-10) days (p < .001), respectively]. At last follow-up, one patient underwent a secondary RFA for recurrence. VAS improvement was 7.5 (3-10) and 6.5 (4-9) (p = .945) in the RFA and OSR groups, respectively. The overall complication rate was 8.3% (1/12) and 18.8% (3/16) in the RFA and OSR groups, respectively. CONCLUSIONS: If there is sufficient cerebrospinal fluid between the spinal OO lesion and spinal cord/nerve root (more than 1 mm), RFA is effective and safe for treatment of well-selected spinal OO, showing reduced operating time, blood loss, in-hospital stay, and complications compared to OSR. However, OSR is still recommended in cases with spinal cord/nerve root compression.

Atypical Radiographic Features of Aggressive Vertebral Hemangiomas.

BACKGROUND: Vertebral hemangioma (VH) is one of the most common benign spinal tumors and can be aggressive in some cases. While most aggressive VHs have typical radiographic features, including vertical striations, a honeycomb appearance, and/or a "polka-dot sign" in computed tomography (CT) scans, cases with atypical features might complicate diagnosis. This study aimed to determine the range and frequency of these atypical features. METHODS: In this retrospective study, to identify the typical and atypical features of aggressive VH, pretreatment CT and magnetic resonance imaging (MRI) were reviewed retrospectively by 1 radiologist and 1 orthopaedic surgeon. Percutaneous biopsies were performed to confirm the VH in atypical cases. RESULTS: A total of 95 patients with aggressive VHs were treated in our hospital from January 2005 to December 2017. Thirty-four (36%) of the lesions showed at least 1 atypical radiographic feature: 16 patients (17%) had a vertebral compression fracture, 11 patients (12%) had expansive and/or osteolytic bone destruction without a honeycomb appearance and/or "polka-dot sign", 11 patients (12%) had obvious epidural osseous compression of the spinal cord, 12 patients (13%) had involvement of >1 segment, 9 patients (10%) had a VH centered in the pedicle and/or lamina, and 8 patients (8%) had atypical MRI signals. Forty-three patients underwent percutaneous biopsies, which had an accuracy of 86%. CONCLUSIONS: Based on radiographic analysis, aggressive VH can be classified as typical or atypical. More than one-third of aggressive VH lesions may have at least 1 atypical feature. CT-guided biopsies are indicated for these atypical cases.

Clinical features and treatment outcomes of Langerhans cell histiocytosis of the spine.

BACKGROUND CONTEXT: Langerhans cell histiocytosis (LCH) of the spine is a relatively rare condition with unknown etiology. The diagnosis and treatment protocols for spine LCH remain controversial. PURPOSE: In this study, we evaluated the efficacy and safety of our proposed diagnosis and treatment protocol introduced in 2009. STUDY DESIGN: This is a retrospective study. PATIENT SAMPLE: A total of 110 patients with spine LCH who had been diagnosed and treated in our hospital from October 1997 to November 2015 were included in this study. OUTCOME MEASURES: The age, gender, symptoms, neurologic function, lesion distribution, radiological features, pathology, treatment, outcome, and treatment complications of the patients were collected. Visual analog scale (VAS) for pain and Frankel scale for neurologic status were also documented. METHODS: We retrospectively reviewed 110 patients with spine LCH who had been diagnosed and treated in our hospital from October 1997 to November 2015. The indications for computed tomography (CT)-guided biopsy and surgery for spine LCH have become more stringent since 2009. In cases of a solitary spinal lesion, immobilization and observation were usually first suggested. Chemotherapy was suggested for cases with multifocal LCH lesions, and low-dosage radiotherapy was restricted to recurrent solitary lesion. This project was supported by our hospital (No. Y71508-01) (¥ 400,000). RESULT: This series included 69 male and 41 female patients (age range, 1-52 years). Pain was the most common symptom (93.6%, 103/110). Pathologic diagnosis was achieved in 72 cases (65.5%). CT-guided biopsies were performed in 91.3% (42/46) and 73.2% (41/56) of cases before and after 2009, respectively (p=.02). Ninety-eight cases (89.1%) were followed up for a mean 66.3 (range, 24-159) months. Immobilization and observation were performed in 25.9% (14/54) and 75.0% (42/56) of cases before and after 2009, respectively (p<.001). Approximately 35.2% (19/54) and 10.7% (6/56) of cases had surgery (p=.002) before and after 2009, respectively. During the follow-up, no significant difference was found in the outcomes between the two groups treated before and after 2009 (p=.64). CONCLUSION: Biopsy is not mandatory for typical spine lesions of LCH. Given the self-healing tendency of spine LCH, immobilization and observation remain the first-choice treatments for LCH lesions. Conservative biopsy and treatment protocols might be more appropriate for spinal LCH.

CT-guided percutaneous radiofrequency ablation of spinal osteoid osteoma.

BACKGROUND: This study evaluated the feasibility, efficacy and safety of CT-guided percutaneous radiofrequency ablation in patients with spinal osteoid osteoma. METHODS: Two patients suffered spinal osteoid osteoma were treated with CT-guided percutaneous radiofrequency ablation under local anesthesia. Lesions located in sacral vertebrae and cervical vertebrae, which were adjacent to nerve root and spinal canal respectively. Tumors were treated under 90°C radiofrequency temperature lasting 4 minutes by an electrode placement. Visual analog scale was used to evaluate the pain improvement. RESULTS: No complications were observed pre- and post-operation. Patients recovered to normal activities immediately and achieved complete pain relief in 24 hours. No symptoms were recurrent in 5 months and 4 months follow up. Mild scoliosis has been recovered in case 2. CONCLUSIONS: CT-guided percutaneous radiofrequency ablation of spinal osteoid osteoma is safe, effective and has more clinical benefits. The long-term outcome needs further observation.