Peripheral nerve sheath tumor: differentiation of malignant from benign tumors with conventional and diffusion-weighted MRI.

OBJECTIVES: To evaluate potential of conventional MRI and diffusion-weighted imaging (DWI) for differentiating malignant from benign peripheral nerve sheath tumors (PNSTs). METHODS: Eighty-seven cases of malignant or benign PNSTs in the trunk or extremities that underwent conventional MRI with contrast enhancement, DWI, and pathologic confirmation between Sep. 2014 and Dec. 2017 were identified. Of these, 55 tumors of uncertain nature on MRI were included. Tumor size, signal, and morphology were reviewed on conventional MRI, and apparent diffusion coefficient (ADC) values of solid enhancing portions were measured from DWI. Patient demographics, MRI features, and ADC values were compared between benign and malignant tumors, and robust imaging findings for malignant peripheral nerve sheath tumors (MPNSTs) were identified using multivariable models. RESULTS: A total of 55 uncertain tumors consisted of 18 malignant and 37 benign PNSTs. On MRI, tumor size, margin, perilesional edema, and presence of split fat, fascicular, and target signs were significantly different between groups (p < 0.05), as were mean and minimum ADC values (p = 0.002, p < 0.0001). Most inter-reader agreement was moderate to excellent (κ value, 0.45-1.0). The mean ADC value and absence of a split fat sign were identified as being associated with MPNSTs (odds ratios = 13.19 and 25.67 for reader 1; 49.05 and 117.91 for reader 2, respectively). The C-indices obtained by combining these two findings were 0.90 and 0.95, respectively. CONCLUSIONS: Benign and malignant PNSTs showed different features on MRI and DWI. A combination of mean ADC value and absence of split fat was excellent for discriminating malignant from benign PNSTs. KEY POINTS: • It is important to distinguish between malignant peripheral nerve sheath tumors (MPNSTs) and benign peripheral nerve sheath tumors (BPNSTs) to ensure an appropriate treatment plan. • On conventional MRI and diffusion-weighted imaging (DWI), MPNSTs and BPNSTs showed significant differences in tumor size, margin, presence of perilesional edema, and absence of split fat, fascicular, and target signs. • Absence of a split fat sign and mean apparent diffusion coefficient (ADC) values were robust imaging findings distinguishing MPNSTs from BPNSTs, with a C-index of > 0.9.

Role of inferomedial supporting screws for secondary varus deformity in non-osteoporotic proximal humerus fracture: A biomechanical study.

INTRODUCTION: The purpose of this study was to evaluate the effect of a medial support screw through a proximal humerus fracture. For this purpose, we verified whether the biomechanics are different according to the position of the screw while using the same number of screws. In addition, we tried to verify whether the insertion of additional inferomedial screws would make a difference in stability. MATERIALS AND METHODS: Twenty-four proximal humerus bones were included in the study. A two-part fracture was created and fixed using a locking plate. Cyclic loading and load-to-failure test were applied to three groups: group A (proximal 6 screws + calcar screws), group B (proximal 6 screws), and group C (proximal 4 screws + calcar screws). Interfragmentary gaps were measured following cyclic loading and compared. The failure was defined when the bone breakage or medial gap closing was observed during ultimate failure load applied. The load-to-failure, maximum displacement, stiffness, and yield load were recorded and compared. RESULTS: The interfragmentary gap was differently reduced by 0.29 ± 0.14 mm, 0.73 ± 0.25 mm, and 0.53 ± 0.09 mm following 1000 cyclic loading for groups A, B, and C, respectively. The load-to-failure was 945.22 ± 101.02 N, 941.40 ± 148.90 N, and 940.58 ± 91.78 N in groups A, B, and C, respectively. The stiffness of group A (214.76 ± 34.0 N/mm) was superior when compared to that of group C (171.12 ± 23.0 N/mm; p = 0.025). The maximum displacement prior to failure, yield load, showed no significant difference between comparative groups. CONCLUSION: Our study did not show any additional biomechanical effects with the use of inferomedial supporting screws in non-osteoporotic proximal humerus fracture, besides making the fracture-plate construct stiff. The role of the inferomedial supporting screw was also unclear. However, the groups that used increased screw fixation and inferomedial screw insertion seemed to be more resistant to cyclic loading.

Risk Factors for Diagnostic Failure of Ultrasound-Guided Core Needle Biopsy of Soft-Tissue Tumors Based on World Health Organization Classification Category and Biologic Potential.

OBJECTIVE. The purpose of this study is to evaluate the diagnostic outcome of ultrasound (US)-guided core needle biopsy (CNB) of soft-tissue tumors and to assess the factors associated with significant diagnostic failure. MATERIALS AND METHODS. We performed a retrospective analysis of biopsy specimens obtained from patients with soft-tissue tumors of the extremities and superficial trunk who underwent both US-guided CNB and surgical resection. In accordance with the World Health Organization classification, biopsy results and findings from final histologic analysis of the surgically resected specimen (hereafter known as final histologic findings) were categorized in terms of biologic potential as benign, intermediate (locally aggressive), intermediate (rarely metastasizing), or malignant. Biopsy results were considered to show a significant diagnostic failure if they resulted in incorrect classification of biologic potential compared with final histologic findings, if results were indeterminate, or if nondiagnostic specimens were obtained. World Health Organization classification categories and the biologic potential of the tumors according to final histologic findings were assessed to identify any relationship with diagnostic failure of CNB, as were other tumor- and patient-related factors. RESULTS. Significant diagnostic failure was seen for 40 of 303 biopsies (13.20%). Multivariate analysis showed a significant association between diagnostic failure and adipocytic tumors (odds ratio [OR], 9.686; p = 0.037) or vascular tumors (OR, 40.115; p = 0.005); intermediate (rarely metastasizing) biologic potential (OR, 12.279; p = 0.001), or malignant biologic potential (OR, 5.668; p < 0.001); and discordance between radiologic and final histologic findings or indeterminacy of biologic potential (OR, 2.500; p = 0.034). CONCLUSION. The World Health Organization classification categories (adipocytic or vascular), biologic potential (intermediate [rarely metastasizing] or malignant), and discordance between radiologic and final histologic findings or indeterminacy of biologic potential were found to be independent risk factors for significant diagnostic failure of CNB of soft-tissue tumors.

Loosening and revision rates after total shoulder arthroplasty: a systematic review of cemented all-polyethylene glenoid and three modern designs of metal-backed glenoid.

BACKGROUND: Several modern designs of metal-backed glenoids (MBG) have been devised to overcome flaws such as loosening and a high failure rate. This review aimed to compare rates of complications and revision surgeries between cemented polyethylene glenoid (PEG) and three examples of modern MBG designs. METHODS: Literature search was carried out using PubMed, Cochrane Library, EMBASE, and Google Scholar using MeSH terms and natural keywords. A total of 1186 articles were screened. We descriptively analyzed numerical data between the groups and statistically analyzed the categorical data, such as the presence of radiolucent line, loosening, and revision surgery (failure). Articles were divided into three groups based on follow-up duration: < 36-month, 36-72-month, and > 72-month subgroups. RESULTS: This study included 35 articles (3769 shoulders); 25 on cemented PEG and ten on the modern MBG. Mean age was 66.4 (21-93) and 66.5 years (31-88). The mean duration of follow-up was 73.1 (12-211) and 56.1 months (24-100). Overall, the rate of the radiolucent line was 354/1302 (27%) and 47/282 (17%), the loosening rate was 465/3185 (15%) and 22/449 (5%), and the failure rate was 189/3316 (6%) and 11/457 (2%), for PEG and MBG, respectively. The results of < 36-month and 36-72-month subgroups showed lower rates of radiolucency and loosening in the cemented PEG group, but there was no significant difference in failure rate (P = 0.754 and 0.829, respectively). In the > 72-month subgroup, MBG was better in terms of loosening (P < 0.001) and failure rates (P = 0.006). CONCLUSIONS: The modern MBG component, especially TM glenoid, seems to be a promising alternative to cemented PEGs, based on subgroup revision rates according to the follow-up duration and overall results of ROM and clinical scores. All polyethylene glenoids tend to increase loosening and failure over time. Three modern MBG designs seem to have no difference in failure, at least in the < 36-month and 36-72-month subgroups compared to the cemented PEG. More long-term follow-up studies on modern MBG should be ultimately conducted. LEVEL OF EVIDENCE: Level IV, systematic review.

Navigation-assisted anchor insertion in shoulder arthroscopy: a validity study.

BACKGROUND: This study aimed to compare conventional and navigation-assisted arthroscopic rotator cuff repair in terms of anchor screw insertion. METHODS: The surgical performance of five operators while using the conventional and proposed navigation-assisted systems in a phantom surgical model and cadaveric shoulders were compared. The participating operators were divided into two groups, the expert group (n = 3) and the novice group (n = 2). In the phantom model, the experimental tasks included anchor insertion in the rotator cuff footprint and sutures retrieval. A motion analysis camera system was used to track the surgeons' hand movements. The surgical performance metric included the total path length, number of movements, and surgical duration. In cadaveric experiments, the repeatability and reproducibility of the anchor insertion angle were compared among the three experts, and the feasibility of the navigation-assisted anchor insertion was validated. RESULTS: No significant differences in the total path length, number of movements, and time taken were found between the conventional and proposed systems in the phantom model. In cadaveric experiments, however, the clustering of the anchor insertion angle indicated that the proposed system enabled both novice and expert operators to reproducibly insert the anchor with an angle close to the predetermined target angle, resulting in an angle error of < 2° (P = 0.0002). CONCLUSION: The proposed navigation-assisted system improved the surgical performance from a novice level to an expert level. All the experts achieved high repeatability and reproducibility for anchor insertion. The navigation-assisted system may help surgeons, including those who are inexperienced, easily familiarize themselves to of suture anchors insertion in the right direction by providing better guidance for anchor orientation. LEVEL OF EVIDENCE: A retrospective study (level 2).

Uniplane medial opening wedge high tibial osteotomy relative to a biplane osteotomy can reduce the incidence of lateral-hinge fracture.

PURPOSE: With surgical modifications reflecting plate design differences of the specific rigid locking plate adding a metal wedge, uniplane high tibial osteotomy (HTO) has fewer lateral-hinge fractures and fewer plate irritations than biplane HTO. METHODS: Uniplane HTO with a rigid locking plate adding a metal wedge was compared with biplane HTO with a rigid locking plate including a proximal D-hole. For comparison, the HTO patients' medical records and radiological results in a single institution were retrospectively reviewed. The Oxford knee score 2 years post-operation, CT scan at post-operative day 2 and serial standing long-bone scanography were reviewed to evaluate clinical outcome and radiological results, including the incidence of lateral-hinge fracture, plate irritation and correction loss to varus alignment. RESULTS: A total of 103 knees, including 59 uniplane HTO and 44 biplane HTO, were enrolled. The Oxford scores were 38.1 ± 7.8 in the uniplane group and 35.9 ± 8.3 in the biplane group (ns). On CT scans, more lateral-hinge fractures developed in the biplane group, and seven knees (12%) of the uniplane group and 12 knees (27%) of the biplane group had Takeuchi type I stable hinge fracture (p < 0.05); unstable fracture was not noted in either group. Plate irritation occurred in nine knees (19%) of the uniplane group and in 14 knees (32%) of the biplane group, and the difference was statistically significant (p < 0.05). CONCLUSION: In clinical situations including the use of surgical modifications reflecting plate design differences, fewer lateral-hinge fractures developed after uniplane medial opening-wedge HTO compared with biplane HTO. Uniplane HTO potentially represents a better option than biplane HTO for the prevention of lateral-hinge fracture. LEVEL OF EVIDENCE: IV.

Range-of-motion improvement and complication rate in open and arthroscopic osteocapsular arthroplasty for primary osteoarthritis of the elbow: a systematic review.

PURPOSE: To analyze ROM changes by using a Bayesian method, to compare complication and re-operation rates between open osteocapsular arthroplasty (OPEN) and arthroscopic osteocapsular arthroplasty (ARTHRO) for primary osteoarthritis of the elbow, and find evidence-based tendencies. METHODS: The PubMed, Cochrane Library, and Embase databases were searched. We performed descriptive analysis to compare ARTHRO and OPEN, a Bayesian analysis of ROM changes, and methodological assessment to determine the tendencies of OPEN and ARTHRO. RESULTS: Eighteen articles (625 patients, 634 elbows) were analyzed. There were 11 articles on OPEN and 8 articles on ARTHRO (1 article was a comparative study between OPEN and ARTHRO). According to the Bayesian method, flexion and total arc of flexion-extension increased more with OPEN than with ARTHRO. Further, ARTHRO showed a narrower width in the ROM graph than OPEN. The number of complications was 17 (5.1%) and five (2.0%), and the number of re-operations was 32 (9.5%) and 14 (5.6%) for OPEN and ARTHRO, respectively. By analyzing six high-quality articles, we found three tendencies: OPEN and ARTHRO were both effective for improving pain score, flexion-extension arc, and functional outcome; OPEN did not improve the pronation-supination arc; and there was a weak tendency that OPEN was more effective than ARTHRO for improving the flexion arc. CONCLUSION: Both OPEN and ARTHRO improved ROM and clinical scores. The Bayesian method indicated that although OPEN increased the flexion and flexion-extension arc more than ARTHRO, ARTHRO resulted in a relatively consistent surgical outcome. Additionally, OPEN caused relatively higher complication and re-operation rates than ARTHRO.

Distinguishing necrotizing from non-necrotizing fasciitis: a new predictive scoring integrating MRI in the LRINEC score.

OBJECTIVES: To develop and validate a scoring system integrating MRI and laboratory findings to differentiate necrotizing fasciitis (NF) from non-necrotizing fasciitis (non-NF). METHODS: This retrospective study included 144 subjects who underwent surgery in one of three tertiary referral centers for NF or cellulitis with non-NF. The development cohort consisted of 96 subjects (NF = 47; non-NF = 49) from one center, and the validation cohort consisted of 48 subjects (NF = 23; cellulitis with non-NF = 25) from two different centers. The Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC) scoring system and five MRI findings (thickening of the intermuscular deep fascia ≥ 3 mm, extensive involvement of the deep fascia, multi-compartmental involvement in one extremity, presence of gas, and contrast-enhancement pattern) were included in univariate and multivariate logistic regression analysis to identify independent predictors of NF. An additive scoring system was developed using the coefficients of the final regression model. Model performance was assessed for discrimination and calibration. The scoring system was externally validated. RESULT: The final scoring system consisted of three variables: thickening of the deep fascia ≥ 3 mm, multi-compartmental involvement, and LRINEC score. The new predictive model showed improved performance (area under the receiver operating characteristic curve [AUC], 0.862; positive and negative predictive values, 82% and 79%, respectively), compared with the LRINEC score alone (0.814, 77% and 67%, respectively). The model also showed good discrimination with the external validation dataset (AUC, 0.933). CONCLUSIONS: Differentiation of NF from severe cellulitis with non-NF can be achieved with the new predictive scoring system. KEY POINTS: • The new predictive scoring system integrating two MRI findings with the LRINEC score can help in the differentiation of necrotizing fasciitis from severe cellulitis with non-necrotizing fasciitis. • Thickening of the deep fascia ≥ 3 mm and multi-compartmental involvement were the most important MRI findings for the differentiation.

Added value of diffusion-weighted imaging to conventional MRI for predicting fascial involvement of soft tissue sarcomas.

OBJECTIVES: This study was conducted to evaluate the added value of diffusion-weighted imaging (DWI) to conventional magnetic resonance imaging (MRI) for predicting fascial involvement of soft tissue sarcomas located in close proximity to fascial boundaries. METHODS: This retrospective study included 29 patients with surgically resected soft tissue sarcomas located in proximity to deep fascia and with a curvilinear tail-like hyperintensity in the adjacent fascia on T2-weighted images. All patients underwent conventional MRI and DWI at 3.0 T and had detailed histologic reports on involvement of fascia. Two musculoskeletal radiologists with 21 and 1 year of experience independently reviewed conventional MRI and conventional imaging with added DWI. Readers scored their confidence for tumor involvement of fascia using a three-point scale. Diagnostic performance (area under the curve [Az]) of the two MRI sets was assessed with receiver-operating characteristic curve analysis. RESULT: Fascial involvement was present in 22/29 patients (75.9%). Both readers showed improvement in diagnostic performance with the addition of DWI (Az, from 0.545 to 0.792 and from 0.646 to 0.792 for reader 1 and reader 2, respectively). Adding DWI did not improve sensitivity or specificity for either reader (p > 0.05). Interobserver agreement for the confidence scores improved from fair to moderate with the addition of DWI (κ, from 0.390 to 0.560). CONCLUSIONS: Adding DWI to conventional MRI improved diagnostic performance on prediction of fascial involvement of soft tissue sarcomas located in proximity to fascia, without significant improvement in sensitivity or specificity. KEY POINTS: • Adding DWI to conventional MRI improved readers' confidence level for the prediction of fascial involvement of soft tissue sarcomas that are close to the deep fascia. • Addition of DWI also improved interobserver agreement. • Conversely, compared with conventional MRI, adding DWI did not significantly improve the sensitivity or specificity for the detection of fascial involvement.

Lateral epicondylitis: Associations of MR imaging and clinical assessments with treatment options in patients receiving conservative and arthroscopic managements.

OBJECTIVES: We assessed the implications of MR imaging with clinical history in lateral epicondylitis management by evaluating imaging and clinical features in patients with lateral epicondylitis treated conservatively or operatively. METHODS: Sixty patients with lateral epicondylitis treated conservatively (n = 38) or operatively (n = 22) from 2011-2015 were included. MR imaging findings of common extensor tendon (CET), lateral collateral ligament (LCL) complex, muscle oedema, ulnar nerve and elbow joint were reviewed. Clinical data recorded were frequency, duration and intensity of pain, history of trauma and injection therapy, range of motion. RESULTS: MRI-assessed CET and LCL complex abnormalities, muscle oedema, radiocapitellar joint widening, joint effusion/synovitis, pain frequency and intensity differed significantly between the two groups (p < .05) with increased severity in operative group. Persistent pain (OR 12.2, p < .01), CET abnormality on longitudinal plane (OR 7.5, p = .03 for grade 2; OR 22.4, p < .01 for grade 3) and muscle oedema (OR 6.7, p = .03) were major factors associated with operative treatment. Area under the ROC curve of predicted probabilities for combination of these factors was 0.83. CONCLUSION: MR imaging, combined with clinical assessment, could facilitate appropriate management planning for patients with lateral epicondylitis. KEY POINTS: • MRI can reflect different disease severity between patients treated conservatively/operatively. • CET abnormality, muscle oedema were major MRI findings with operative treatment. • Patients in operative group were more likely to experience persistent pain. • MRI plus clinical symptoms could facilitate appropriate management for lateral epicondylitis.

Clear Cell Hidradenoma: Characteristic Imaging Features on Ultrasonography, Computed Tomography, and Magnetic Resonance Imaging.

OBJECTIVES: The purpose of this study was to evaluate the imaging features of clear cell hidradenoma on ultrasonography (US), computed tomography (CT), and magnetic resonance imaging (MRI). METHODS: The radiologic and pathologic databases at 2 medical institutions were searched retrospectively from 2004 to 2016 to identify patients with a diagnosis of clear cell hidradenoma. Ultrasonographic, CT, and MRI features were described, and pathologic specimens were reviewed. RESULTS: There were 5 female and 4 male patients. The mean patient age was 48.9 years (range, 28-70 years). Five patients underwent only US; 2 patients underwent only CT; 1 patient underwent both US and CT; and 1 patient underwent US and MRI. Most of the tumors were located primarily in the subcutaneous fat layer. The mean tumor size was 18.4 mm. On US, 6 masses had a heterogeneous echo texture, including an anechoic portion with protruding echogenic portions. Two masses had multiple septa in the anechoic portion. On color Doppler US, blood flow was both central and peripheral in 5 patients. All 3 cases seen on CT presented as a low-attenuation mass with an enhanced solid internal nodule. On MRI, the mass showed heterogeneous signal intensity on T2-weighted images and enhancement of the peripheral wall and internal solid component on contrast-enhanced T1-weighted images. CONCLUSIONS: Clear cell hidradenoma is usually located in the subcutaneous fat layer, has a well-defined margin, appears as a cystic mass with an internal solid nodule, and occasionally has multiple septa on US, CT, and MRI.

Changes in the T2 value of cartilage after meniscus transplantation over 1 year.

OBJECTIVES: To evaluate the changes in the mean T2 values of articular cartilage on serial follow-up images up to 1 year in patients who underwent lateral meniscus allograft transplantation (MAT). METHODS: Fifty-two patients who underwent lateral MAT surgery at our hospital were evaluated preoperatively and at 2 days, 6 weeks, 3 months, 6 months, and 1 year after MAT using 3.0-T magnetic resonance imaging (MRI) that included T2 mapping. T2 value changes according to the arthroscopic grading of chondromalacia were evaluated in the lateral and medial compartment. Lysholm scores were obtained pre- and postoperatively. RESULTS: The T2 values of cartilage were significantly increased 2 days after operation, and then gradually reduced to the baseline level after 1 year in both compartments. In morphologic assessment performed after 1 year, most areas (92.9 %) showed no interval change of chondromalacia grade. Lyshom knee scores increased significantly from the mean preoperative value of 62.5 (range, 23-95) to 89.7 (range, 64-100) at 1 year (p < 0.001). CONCLUSION: Mean T2 values of cartilage following MAT exhibited a return to baseline level after 1 year. T2 measurement can be a useful tool for quantitative evaluation of postoperative cartilage changes compared to conventional MRI. KEY POINTS: • T2 mapping provides objective data for longitudinal monitoring following surgery. • Increased cartilage T2 values post-MAT returned to baseline in one year. • Further studies are required to predict the chondroprotective effect of MAT.

Sonographic Differentiation Between Schwannomas and Neurofibromas in the Musculoskeletal System.

OBJECTIVES: The purpose of this study was to determine key features and define a strategy for differentiation between schwannomas and neurofibromas using sonography. METHODS: This retrospective study was approved by the Institutional Review Board at our hospital, and informed consent was waived. We reviewed sonograms of pathologically proven schwannomas and neurofibromas of the extremities and body wall. On grayscale images, tumors were evaluated on the basis of their size, maximum-to-minimum diameter ratio, shape, contour, margin, location, encapsulation, echogenicity, echo texture, cystic changes, presence of intratumoral calcifications, presence of a target sign, and presence of an entering or exiting nerve. If an entering or exiting nerve was identified, the nerve-tumor position and nerve-tumor transition were characterized. On color Doppler images, the presence and amount of vascularity were evaluated. Student t tests were used for analysis of continuous variables (size, maximum-to-minimum diameter ratio, and age); χ(2) and Fisher exact tests were used for analysis of categorical variables. RESULTS: A total of 146 pathologically proven tumors, including 115 schwannomas and 31 neurofibromas of the extremities and body wall, were included. The maximum diameter, maximum-to-minimum diameter ratio, contour, cystic portion, nerve-tumor position, nerve-tumor transition, and vascularity were significantly different in schwannomas versus neurofibromas (P < .05), and a lobulated contour, fusiform shape, and hypovascularity of neurofibromas could be helpful for differentiation when a prediction model is considered. The nerve-tumor position, nerve-tumor transition, and maximum-to-minimum diameter ratio were also significantly different between groups (P < .05) and thus could be useful for differentiation of neurogenic tumors. CONCLUSIONS: Sonographic findings are helpful in differentiating between schwannomas and neurofibromas.

Conservative treatment after failure of internal fixation for periprosthetic femoral fractures: a report of two cases.

Osteosynthesis using compression or locking plate following indirect fracture reduction and using a minimally invasive technique has been recommended for the surgical treatment of Vancouver B1 and C periprosthetic femoral fractures. Recent advancements in fracture healing emphasize the significance of the type of mechanical stability depending on fracture patterns and the importance of the preservation of the blood supply around the fracture sites. We report two cases of mechanical failure after internal fixation of periprosthetic femoral fractures despite adherence to the principles of fracture care. Both patients were treated conservatively with a thigh cuff cast due to other concurrent issues. Bone healing was successfully achieved in both cases as a result of the preservation of the tissues and the biology around the fractures during the initial operations. We present our experiences of conservative management together with the preservation of the biology around the fracture site, as viable alternative options for difficult and traumatic revision surgery in cases of failed periprosthetic fracture fixation procedures.

Bone involvement in secondary syphilis: a case report and systematic review of the literature.

Bone involvement is an unusual manifestation of secondary syphilis, but little information is available in the English-language literature. We carried out a systematic review of the English-language literature from 1964 to 2013, describing cases of secondary syphilis with bone involvement. We also describe a case of secondary syphilis with multiple osteolytic lesions, mimicking metastatic cancer or myeloma, which was included in an analysis of 37 eligible cases of secondary syphilis with bone involvement. Of these 37 patients, 28 (76%) patients were male, and the median age was 32 years (range, 12-64 years). Eleven (30%) patients had human immunodeficiency virus (HIV) infection with a median CD4 lymphocyte count of 343 cells/mm (range, 130-689 cells/mm). The diagnosis of early syphilis was suspected based on mucocutaneous findings in 28 (76%) cases. In the remaining 9 (24%) cases, high titers of nontreponemal serologic tests were the only evidence of early syphilis. The median venereal disease research laboratory (VDRL) titer was 1:64 (range, 1:8-1:320), and median rapid plasma reagin (RPR) titer was 1:64 (range, 1:16-1:512). The bones most often affected were long bones of the limbs (n = 22) and skull (n = 21). The bone lesions were multifocal in 27 (73%) cases and osteolytic in 19 (51%) cases. The treatment of syphilitic bone lesions was medical only in most patients, and prognosis was favorable with high-dose penicillin therapy. Clinical features and outcome between HIV-uninfected and HIV-infected patients were not different. Knowledge of this rare entity may lead to early diagnosis and appropriate management.

Radiation exposure for fluoroscopy-guided lumbosacral epidural steroid injections: comparison of the transforaminal and caudal approaches.

STUDY DESIGN: A retrospective investigation. OBJECTIVE: We evaluated and compared the radiation exposure caused by using the fluoroscopy-guided transforaminal and caudal approaches of lumbosacral epidural steroid injection (ESI). SUMMARY OF BACKGROUND DATA: Only a few studies focused on the radiation exposure to patients who underwent lumbosacral ESI for pain management. MATERIALS AND METHODS: A total of 228 patients (83 males, 145 females; mean age, 63.3 y) who received lumbosacral ESI were included. Transforaminal ESI was performed in 181 patients (67 males, 114 females; mean age, 61.3 y) and caudal ESI was used in 47 patients (16 males, 31 females; mean age, 69.7 y). All ESIs were performed under a single-plane fluoroscopic guidance by 1 musculoskeletal radiologist. The kerma-area product (KAP) and fluoroscopy time were recorded in all patients. Both measurements were correlated and compared for each approach. RESULTS: KAP was 3.02-1048.2 µGy m (mean, 101.7 µGy m; median, 67.8 µGy m) for transforaminal ESI and 16.0-604.5 µGy m (mean, 101.8 µGy m; median, 54.6 µGy m) for caudal ESI. The fluoroscopy time was 11-161 seconds for transforaminal ESI (mean, 36.0 s; median, 29 s) and 4-78 seconds (mean, 18.2 s; median, 13 s) for caudal ESI. KAP and fluoroscopy time were positively correlated for each approach (P<0.001). Fluoroscopy time was significantly longer for transforaminal ESI (correlation coefficient=-0.77, P=0.000). After correction for the fluoroscopy time, KAP was less in transforaminal ESI than in caudal ESI (correlation coefficient=0.74, P=0.000). CONCLUSIONS: The longer the fluoroscopy time, the greater the KAP in both transforaminal and caudal ESIs. The fluoroscopy time for transforaminal ESI was longer than that for caudal ESI. However, KAP of transforaminal ESI was less than that of the caudal ESI, after being corrected for the length of fluoroscopy time.

Candida spondylitis: Comparison of MRI findings with bacterial and tuberculous causes.

OBJECTIVE: Candida spondylitis is relatively uncommon and is usually encountered as an opportunistic infection. We analyzed the MRI characteristics of biopsy-proven cases of Candida spondylitis, and compared the findings with bacterial or tuberculous spondylitis. MATERIALS AND METHODS: The study included patients with infectious spondylitis who underwent MRI and biopsy from 1998 to 2011 (60 patients; mean age 56 ± 18 years). MR images were analyzed with respect to the number of involved vertebrae, contrast enhancement pattern, signal intensity of spinal inflammatory masses on T2-weighted imaging, paraspinal abscess size, intervertebral disk destruction, subligamentous spread, and skip lesions. The Fisher exact test and analysis of variance were used for statistical analysis. RESULTS: There were 10 cases of Candida spondylitis, and 29 and 21 cases of bacterial and tuberculous spondylitis, respectively. On MRI, disk destruction was seen in 50%, 93%, and 30% of Candida, bacterial, and tuberculous cases, respectively. Subligamentous spread of infection was noted in 22%, 10%, and 85%. Paraspinal inflammatory masses were seen in 100%, 100%, and 76%, and abscesses in 100%, 66%, and 90%, of Candida, bacterial, and tuberculous cases, respectively. Paraspinal inflammatory masses contained low T2 signal intensity portions in 80%, 21%, and 67%, and skip lesions were seen in 0%, 10%, and 14%, respectively. Small abscesses were noted in 100%, 76%, and 35% of Candida, bacteria, and tuberculosis infections, respectively. Candida involved 2.3 ± 0.4 vertebrae compared with 2.3 ± 0.9 and 3.0 ± 1.7 in bacterial and tuberculous, respectively. Differences in the three groups were statistically significant (p < 0.05) except for the number of involved vertebrae, and skip lesions. CONCLUSION: Candida spondylitis can be suspected when infectious lesions contain low-signal spinal inflammatory masses on T2-weighted imaging, small paraspinal abscesses, and in immunocompromised patients.

Encapsulated fat necrosis mimicking subcutaneous liposarcoma: radiologic findings on MR, PET-CT, and US imaging.

We present a case of a subcutaneous encapsulated fat necrosis of the upper extremity that mimicked subcutaneous liposarcoma because of heterogeneous signal intensity, its relatively large size, and pronounced enhancement on magnetic resonance imaging (MRI). For this case, we present the radiologic findings including MRI, positron emission tomography-computed tomography (PET-CT), ultrasonography, and radiography. We emphasize the imaging features of this lesion, which has a fibrous capsule and briefly discuss its nomenclature and pathophysiology.

Sagging posterior layer thoracolumbar fascia: can it be the cause or result of adjacent segment diseases?

STUDY DESIGN: A retrospective study. OBJECTIVE: Thoracolumbar fascia (TLF) is an important anatomic structure that plays a role in integrating back muscles and maintaining the stability of lower back. Functional failure of TLF can be one of the factors in the vicious cycle of progressive spinal instability. The purpose of this study is to assess the TLF and correlate it with spinal stability in the instrumented lumbar surgery patients. MATERIALS AND METHODS: From January 2008 to March 2009, 68 consecutive postoperative lumbar or thoracolumbar spine magnetic resonance images were retrospectively reviewed to evaluate the morphologic changes of TLF. It was considered as "sagging posterior layer TLF" when it showed abrupt bulging appearance on parasagittal planes. To determine the spinal stability, flexion and extension lumbar lateral films were also reviewed. The correlation between sagging TLF and adjacent segment disease (ASD) were analyzed. RESULT: Fifty patients (19 males and 31 females, mean age 52.4 y) showed sagging posterior layer TLF, and 32 of them developed ≥1 junctional problems, such as retrolistheses (n=25), compression fractures (n=5), spondylolistheses (n=4), progressive scoliosis (n=4), and segmental instability with bone marrow change (n=2). There was statistically significant correlation between the instrumented surgery and sagging TLF (P-value <0.001). And there was also significant correlation between the sagging TLF and ASD (P-value <0.001). CONCLUSIONS: Morphologic changes of the TLF in postoperative magnetic resonance imaging can be the earliest and predictable findings in the progressive development of the ASD.