A cryptic EWSR1::DDIT3 fusion in myxoid liposarcoma: Potential pitfalls with FISH and cytogenetics.

Myxoid liposarcoma (MLS) is molecularly characterized by fusions involving the DDIT3 gene in chromosome band 12q13; the fusion partner is FUS in band 16p11 in 90-95% of the cases and EWSR1 in band 22q12 in the remaining 5-10%. Hence, molecular studies, often fluorescence in situ hybridization (FISH) for DDIT3 rearrangement, are useful for establishing a correct diagnosis. Although all MLS tumors should have DDIT3 fusions, it is important to be aware of reasons for potential false-negative results. We here present a case of MLS that was negative for FISH for DDIT3, that showed an unexpected t(11;22) at G-banding, but that displayed a characteristic EWSR1::DDIT3 fusion at RNA-sequencing. The results suggest that neoplasia-associated fusions that, due to the transcriptional orientations of the two genes involved, cannot arise through only two double-strand breaks are more likely to be associated with negative FISH-findings and unexpected karyotypes.

The Importance of Perceived Barriers to Women Entering and Advancing in Orthopaedic Surgery in the US and Beyond.

BACKGROUND: Global perceptions of barriers to women in orthopaedics have not been assessed. The purpose of this study was to determine the importance of international barriers to women entering and advancing within orthopaedic surgery. METHODS: An anonymous, online survey was distributed to women medical students, trainees, and practicing surgeons via Women in Orthopaedics Worldwide, the "Women in Ortho" Facebook page, and individual programmes. Participants were asked to rate perceived barriers to (1) pursuing training and (2) career advancement on a scale of 1-5, with 5 being the most important and relative to other barriers. Descriptive statistics and univariate analyses were employed. RESULTS: The survey yielded 237 US (84.0%) and 45 international (16.0%) respondents. Per entering orthopaedic surgery, the most important barriers were male-dominated culture, lack of a strong women mentor, and lack of female representation at home institution. Compared with the US surgeons/trainees, international respondents cited greater societal disapproval (2.8 ± 1.2 vs. 3.4 ± 1.3, P = 0.01). Medical students assigned less importance to lack of exposure, more to lack of resources for creating competitive applications (P < 0.05). Regarding career advancement, lack of women leadership, family responsibilities, and gender-biased selection for promotion were the most important. International surgeons/trainees noted greater concern for societal disapproval (3.5 ± 1.5 vs. 2.6 ± 1.3, P = 0.003) and were more likely to rank sexual harassment in their top three (17.6 vs. 4.2%, P = 0.02). CONCLUSION: While notable differences exist, there is striking similarity across countries and position levels in perceived barriers to women entering and advancing in orthopaedic surgery. LEVEL OF EVIDENCE: III.

Use of Pediatric Outcomes Data Collection Instrument to Evaluate Functional Outcomes in Multiple Hereditary Exostoses.

BACKGROUND: The Pediatric Outcomes Data Collection Instrument (PODCI) is a validated quality-of-life questionnaire with 6 domains designed to provide a standardized method of measuring outcomes in pediatric musculoskeletal conditions. To our knowledge there are no reports on its use in children with multiple hereditary exostosis (MHE). QUESTIONS/PURPOSES: Most published studies on MHE patients have described the efficacy of specific surgical techniques or the specification of deformities. Little is known about the general health status of pediatric patients, the severity of pain, loss of function, and how MHE influences the activities of daily life. We aim to assess the functional levels of MHE pediatric patients with PODCI questionnaire. PATIENTS AND METHODS: As a cross-sectional study, we prospectively administered PODCI to 34 pediatric patients diagnosed with MHE and their families. The score distributions were compared with values published earlier for children and adolescents without musculoskeletal disorders using the Student and Welch t tests. Parents and adolescents' reports were compared using Wilcoxon signed rank test. Physical examination and PODCI score relation were evaluated by Spearman test. RESULTS: Children with MHE have significantly lower scores ( P <0,05) in comparison with unaffected children in all domains using the Student and Welch t test. Parents score differs from children score with statistically relevance in pain and comfort domain ( P <0,5). The Spearman test showed a negative correlation between physical examination and PODCI score with statistical significance. CONCLUSIONS: These results point towards PODCI's capacity in evaluating functional outcomes of pediatric patients with MHE. LEVEL OF EVIDENCE: Diagnostic Study, Level III.

The diagnostic utility of DNA copy number analysis of core needle biopsies from soft tissue and bone tumors.

Morphologic and immunohistochemical analysis of preoperative core needle biopsies (CNB) is important in the management of patients with soft tissue and bone tumors (STBTs). Most SBTB subtypes have more or less extensive DNA copy number aberrations (CNA), potentially providing useful diagnostic information. To evaluate the technical feasibility of single nucleotide polymorphism (SNP) array analysis and the diagnostic usefulness of the copy number profiles, we studied CNBs from 171 patients with suspected STBTs. SNP array analysis could be performed on 168 (98%) of the samples. The CNA profile was compatible with the CNB diagnosis in 87% of the cases. Discrepant cases were dominated by false-negative results due to nonrepresentative material or contamination with normal cells. 70 genomic profiles were indicative of specific histopathologic tumor entities and in agreement with the corresponding CNB diagnoses in 83%. In 96 of the cases with aberrant CNA profiles, the SNP profiles were of sufficient quality for segmentation, allowing clustering analysis on the basis of the Jaccard similarity index. The analysis of these segment files showed three major CNA clusters, based on the complexity levels and the predominance of gains versus losses. For 43 of these CNB samples, we had SNP array data also from their corresponding surgical samples. In 33 of these pairs, the two corresponding samples clustered next to each other, with Jaccard scores ranging from 0.61 to 0.99 (median 0.96). Also, for those tumor pairs that did not cluster together, the Jaccard scores were relatively high (median 0.9). 10 cases showed discrepant results, mainly due to varying degrees of normal cell contamination or technical issues. Thus, the copy number profile seen in a CNB is typically highly representative of the major cell population in the tumor.

New approach in the treatment of refractory vitiligo: CO2 laser combined with betamethasone and salicylic acid solution.

The aim of this study is to evaluate the use of fractional carbon dioxide laser (CO2 ) with betamethasone and salicylic acid solution in the treatment of patients with refractory vitiligo in hands. Each hand of the patient was randomly assigned to one of two groups: lesion treated with fractional carbon dioxide laser associated with betamethasone and salicylic acid solution administration or lesion treated only with betamethasone and salicylic acid solution. We conclude that combined treatment with fractional carbon dioxide laser and betamethasone associated with salicylic acid solution could effectively and safely be used in the treatment of refractory vitiligo.

Radial Neck Fractures in Children and Adolescents: An Examination of Operative and Nonoperative Treatment and Outcomes.

BACKGROUND: Although most pediatric radial neck fractures can be treated with either immobilization alone or closed reduction and immobilization, a small subset result in permanent loss of motion despite surgical management. We sought to characterize the most problematic fractures and correlate final outcomes with both presenting fracture characteristics and the reduction achieved through surgical intervention. METHODS: One hundred ninety-three consecutive children with a radial neck fracture, satisfactory initial treatment data, and follow-up range-of-motion (ROM) data presenting between 1999 and 2012 to our level 1 trauma center were evaluated. The O'Brien classification was used to evaluate angulation on radiographs. Final ROM outcomes were categorized into excellent, good, fair, and poor. ROM data were not used in the operative group if follow-up was <12 weeks (<6 wk in the nonoperative group) or if there was no follow-up after cast removal. RESULTS: Thirteen percent of all patients presenting with radial neck fractures required operative treatment (average age 9.1 y). Of patients treated operatively with adequate ROM data, 26.4% healed with fair or poor outcomes. Patients requiring open management were of older average age (average 10 y old, P=0.02) and had a significantly greater risk of a fair or poor ROM outcome than those treated with closed operative techniques (P=0.02). Patients treated nonoperatively were of a younger average age than those in the operative cohort (8.2 vs. 9.1 y, P=0.03). Patients treated operatively were more likely to develop complications (P=0.004); however, presence of a complication was not predictive of fair or poor outcomes in either the operative (P=0.117) or nonoperative (P=0.264) groups. CONCLUSIONS: Older children are more likely to have more severely displaced radial neck fractures requiring open surgical management, thus resulting in a greater risk of fair or poor outcomes. In the series as a whole, more complications were seen when operative management was required. Final outcomes were not shown to be significantly related to preoperative displacement, postoperative reduction, presence of associated injuries, energy of injury, or treatment complications. LEVELS OF EVIDENCE: Level III­therapeutic.

New insight in the treatment of refractory melasma: Laser Q-switched Nd: YAG non-ablative fractionated followed by intense pulsed light.

The purpose of our study was to verify the results of the association of Q-switched Nd: YAG non-ablative fractionated with intense pulsed light, in order to treat patients with refractory melasma. The combination of these two devices seems to be the best treatment to combat hyperpigmentation produced by melasma, with low occurrence of side effects, which may be justified by the selective photothermolysis at subcellular level.

Acaricidal properties of the essential oil from Zanthoxylum caribaeum against Rhipicephalus microplus.

Zanthoxylum caribaeum Lamarck (Rutaceae) is plant species with a variety of medical applications, including insecticidal activity. This study determined the bioacaricidal activity of the essential oil from Z. caribaeum leaves against engorged Rhipicephalus (Boophilus) microplus (Canestrini, 1887) females using the adult immersion test. For this purpose, three serial concentrations (5.0, 2.5, and 1.25%, vol:vol, in 1% dimetilsulfoxide) of the essential oil were used. Essential oil 5% caused 65% mortality on the first day after treatment, 85% on the second day, and 100% mortality by the fifth day. To our knowledge, this is the first demonstration of the acaricidal activity of the essential oil from Z. caribaeum leaves against cattle ticks.

MDM2 amplification in rod-shaped chromosomes provides clues to early stages of circularized gene amplification in liposarcoma.

Well-differentiated liposarcoma (WDLS) displays amplification of genes on chromosome 12 (Chr12) in supernumerary ring or giant marker chromosomes. These structures have been suggested to develop through chromothripsis, followed by circularization and breakage-fusion-bridge (BFB) cycles. To test this hypothesis, we compared WDLSs with Chr12 amplification in rod-shaped chromosomes with WDLSs with rings. Both types of amplicons share the same spectrum of structural variants (SVs), show higher SV frequencies in Chr12 than in co-amplified segments, have SVs that fuse the telomeric ends of co-amplified chromosomes, and lack interspersed deletions. Combined with the finding of cells with transient rod-shaped structures in tumors with ring chromosomes, this suggests a stepwise process starting with the gain of Chr12 material that, after remodeling which does not fit with classical chromothripsis, forms a dicentric structure with other chromosomes. Depending on if and when telomeres from other chromosomes are captured, circularized or linear gain of 12q sequences will predominate.

Chondroblastoma and chondromyxoid fibroma.

Chondroblastoma and chondromyxoid fibroma are benign but locally aggressive bone tumors. Chondroblastoma, a destructive lesion with a thin radiodense border, is usually seen in the epiphysis of long bones. Chondromyxoid fibroma presents as a bigger, lucent, loculated lesion with a sharp sclerotic margin in the metaphysis of long bones. Although uncommon, these tumors can be challenging to manage. They share similarities in pathology that could be related to their histogenic similarity. Very rarely, chondroblastoma may lead to lung metastases; however, the mechanism is not well understood.

Patient-reported Outcomes After Primary Total Hip Arthroplasty Are Not Affected by the Sex of the Surgeon: A Register-based Study of 8,383 Procedures in Western Sweden.

INTRODUCTION: Female surgeons remain a minority within the field of orthopaedics, particularly in certain specialties such as arthroplasty. There is no scientific evidence on whether the surgeon's sex affects the patient-reported outcome after orthopaedic surgery such as total hip arthroplasty (THA). We therefore aimed to investigate the association between surgeon sex and health-related quality of life after THA. METHODS: Data on primary THAs performed between 2008 and 2016 were collected from 10 hospitals in western Sweden. The data were linked with the Swedish Hip Arthroplasty Register, a regional patient register and the National Board of Health and Welfare, resulting in a data set that included surgeon-related and patient-related data. The outcome of the study was the change in health-related quality of life, measured with the 3-level version of EQ-5D (EQ-5D-3L) Index and EQ-visual analog scale (VAS), before and 1-year after THA. Mixed models, using hierarchical linear regression adjusted for patient sex, age, preoperative health-related quality of life and Charnley classification, were fitted to estimate the gain in EQ-5D-3L Index and EQ-VAS with 95% confidence intervals based on surgeon sex. RESULTS: In total, 8,383 primary THAs were done for osteoarthritis by 193 surgeons. Of those, 37 were women and 156 were men. The regression model was showed that patients operated by female surgeons had a ß-coefficient of gain in EQ-5D-3L Index of -0.001 (-0.022 to 0.021) and a ß-coefficient of gain in EQ VAS of 0.004 (-0.023 to 0.030), compared with patients operated by male surgeons. Similar results were obtained in a sensitivity analysis including attendings only. DISCUSSION: Patients undergoing primary THA reported similar gain in health-related quality of life regardless of surgeon sex. Based on our results, health-related quality of life after primary THA was not associated with the sex of the operating surgeon.

The Influence of Surgeon Sex on Adverse Events Following Primary Total Hip Arthroplasty: A Register-Based Study of 11,993 Procedures and 200 Surgeons in Swedish Public Hospitals.

BACKGROUND: Stereotypes may prevail, but little is known about the influence that the sex of an orthopaedic surgeon may have on outcomes. In a recently published study, there were no differences in the rate of adverse events following total hip arthroplasties (THAs) performed by female or male orthopaedic surgeons. The objective of the present study was to investigate whether there was any difference in adverse events within 90 days following a primary THA performed by either a male or female surgeon in Sweden. METHODS: A retrospective study was performed to evaluate primary THAs performed for osteoarthritis between 2008 and 2016 at 10 hospitals in western Sweden. Local hospital data were linked with the Swedish Hip Arthroplasty Register (SHAR) and with a regional patient register. Data collected from local hospitals and the SHAR included surgeon-related information (e.g., sex, annual volume, and level of training) and patient-related information (e.g., age, sex, and Elixhauser comorbidity index). Adverse events were retrieved from the regional patient register. The definition of adverse events followed the SHAR definition of adverse events. Mixed models were used to investigate the impact of surgeon sex on adverse events. RESULTS: A total of 11,993 primary THAs were performed by 200 surgeons, of whom 17.5% were women. The proportions of adverse events within 90 days were similar for female (6%) and male (7%) surgeons. No association was found between surgeon sex and adverse events (adjusted odds ratio, 0.72; 95% confidence interval, 0.52 to 1.00) when all surgeons (both attendings and residents) were included in the analysis. A sensitivity analysis that included attendings only yielded similar results (adjusted odds ratio, 0.88; 95% confidence interval, 0.60 to 1.29). CONCLUSIONS: Despite a small tendency toward lower rates of adverse events at 90 days after THAs performed by female surgeons, there was no significant association between surgeon sex and the risk of adverse events following THA. LEVEL OF EVIDENCE: Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Correlation between Insulin-Like Growth Factor I and Skeletal Maturity Indicators.

Objective: The purpose of this study was to evaluate the correlation between the growth maturity indicators in orthodontic patients. Design: This cross-sectional study was performed on 37 orthodontic patients (17 males and 20 females). An anamnesis, clinical and image examination, and blood sample collection were performed. The inclusion criteria were non-syndromic Class II patients of both gender, age ranging between 10 to 16 years. The lateral cephalometric radiographs were evaluated using 6-stage cervical vertebrae maturation (CVM) technique. The hand-wrist radiographs were staged using the 11-stage skeletal maturation indicator (SMI) technique. Blood was collected in the same week of the images to quantify IGF-1 levels in serum. Data were tested for normality by Shapiro-Wilk test. The Pearson test was used to determine the correlation strength between the variables (alpha of 5%). Results: A strong correlation was observed only between SMI stages and CVM stages in the total sample (r=0.864; p<0.0001) and according to the gender (r=0.793; p<0.0001 for females; and r=0.753; p<0.0001 for males). IGF-1 was only moderately correlated with SMI stages and CVM stages. Conclusion: Hand-wrist and cervical vertebral stages were strongly correlated among them, however, IGF-1 was only moderately correlated with both skeletal maturity indicators.

Evaluation of essential oils as an ecological alternative in the search for control Rhipicephalus microplus (Acari: Ixodidae).

The cattle tick Rhipicephalus microplus is a significant problem for livestock, causing losses of billions of dollars per year. This work aimed to determine the chemical composition of essential oils obtained from Laurus nobilis and Copaifera officinalis and evaluate activity against engorged R. microplus females. Chemical composition analyzed by GC-MS revealed the presence of 39 components accounting for 95.38% of the oil in L. nobilis, the most abundant being 1,8-cineol (25.7%), trans-sabinene-hydrate (20.8%), and α-terpinil acetate (15.0%). Chemical analysis of C. officinalis oil identified 25 components corresponding to 80.5% of the total constituents, where the major compounds were ß-caryophyllene (21.1%), caryophyllene oxide (10.7%), and α-trans-bergamotene (9.3%). Adult immersion test (AIT) showed that L. nobilis essential oil at 5% or 10% caused 80.5% mortality of engorged females after 24 h and reached 96.9% and 100% mortality on the third day after treatment, respectively. While the essential oil from C. officinalis caused 84.7% mortality after six days at 10% and at 5%, achieved approximately 100% mortality rate at the end of the experiment (day 15). Both essential oils and the combination significantly inhibited egg-laying; however, the combination treatment showed higher effectiveness than the isolated oils at 2.5%. A possible synergic action of L. nobilis and C. officinalis against the cattle tick R. microplus is therefore suggested. The present work introduces a potential alternative for the development of a formulation environment-friendly (green pesticide) used to control cattle tick infestations.

Acaricidal Properties of Bio-Oil Derived From Slow Pyrolysis of Crambe abyssinica Fruit Against the Cattle Tick Rhipicephalus microplus (Acari: Ixodidae).

Slow pyrolysis is a process for the thermochemical conversion of biomasses into bio-oils that may contain a rich chemical composition with biotechnological potential. Bio-oil produced from crambe fruits was investigated as to their acaricidal effect. Slow pyrolysis of crambe fruits was performed in a batch reactor at 400°C and chemical composition was analyzed by gas chromatography-mass spectrometry (GC-MS). The bio-oil collected was used in bioassays with larvae and engorged females of the cattle tick Rhipicephalus microplus. Biological assays were performed using the larval packet test (LPT) and adult immersion test. The GC-MS of crambe fruit bio-oil revealed mainly hydrocarbons such as alkanes and alkenes, phenols, and aldehydes. The bio-oil in the LPT exhibited an LC90 of 14.4%. In addition, crambe bio-oil caused female mortality of 91.1% at a concentration of 15% and a high egg-laying inhibition. After ovary dissection of treated females, a significant reduction in gonadosomatic index was observed, indicating that bio-oil interfered in tick oogenesis. Considering these results, it may be concluded that slow pyrolysis of crambe fruit affords a sustainable and eco-friendly product for the control of cattle tick R. microplus.

Stability of Class II corrections with removable and fixed functional appliances: A literature review.

BACKGROUND: Class II functional appliances have been used in orthodontics for over 100 years. Although the stability of corrections is one of the main goals of orthodontic treatment, there is a paucity of longitudinal studies on the long-term stability of treatment of Class II malocclusion based on functional appliances. METHODS: This narrative review attempts to summarize the limited related evidence available and discusses the clinical implications of important aspects related to occlusal and skeletal changes that arise after Class II malocclusion treatment with functional appliances. RESULTS: The occlusal changes obtained through Class II functional treatment do mostly exhibit long-term stability. While mild posttreatment changes occurred, they were most likely due to physiologic aging processes and not likely associated with actual treatment relapse. Long-term retention in the lower jaw would be particularly beneficial. A stable occlusion with good intercuspation in the posterior arches seems more likely to preserve a Class I occlusion after treatment through dentoalveolar compensatory mechanisms. After treatment, the maxilla and the mandible do grow anteriorly, with the mandible growing more than the maxilla. Patients treated with functional appliances are not likely to develop TMJ disorders over the long term. CONCLUSIONS: Long term skeletal corrections achieved with functional appliances seem to be overall stable. Class II molar and overjet relapses can be likely explained by a combination of tooth movement and an unfavorable posttreatment maxillomandibular growth pattern, especially when combined with unstable interdigitation of the posterior teeth. No specific intermaxillary retention approach has been assessed yet.

Efficacy of corticosteroid in decreasing scoliosis and extending time to loss of ambulation in a single clinic: an effectiveness trial.

PURPOSE: Pharmacologic doses of corticosteroid (CS) have been shown to ameliorate the progression of Duchenne muscular dystrophy (DMD) preserving strength, pulmonary function and ambulation as well as reducing the incidence of scoliosis. However, there are serious side effects of CS, which may impact dose tolerance. The purpose of this study was to compare the magnitude of positive CS effects on patients in our clinic to those reported in the literature. METHODS: We retrospectively reviewed medical records and radiographs of 142 DMD patients who were seen between 1st January 1991 and 31st December 2017. RESULTS: In total, 101 boys met study inclusion criteria. Of these 32 were steroid naïve, 37 took the recommended dose (standard of care, SOC) of Prednisone or Deflazacort, and 32 took a lower dose (LD). Following initiation of CS, both treatment groups showed an increase in weight velocity and decrease in linear growth velocity. Although there was a trend to later loss of ambulation (LOA) in the SOC group relative to the naïve group by one year, this was not significant, however, a small subgroup of boys on Deflazacort showed a 3.4 year later LOA than the naïve group. The incidence of scoliosis was reduced from 69% in the naïve, to 41% in the LD and 47% in the SOC group. CONCLUSIONS: Although there was a reduction in the incidence of scoliosis, it was not as robust as seen elsewhere. Many published studies have inadequate data on scoliosis probably due to the lack of inclusion of orthopaedists in the study group. LEVEL OF EVIDENCE: IV.

Displaced Supracondylar Humerus Fractures in Toddlers.

Gartland type III fracture is the most troublesome type of supracondylar humerus fracture. These injuries most often occur in school age children, but they are seen in pediatric patients of all ages. The goal of this study was to analyze toddlers with Gartland type III fractures to identify clinically significant differences compared with older children. A retrospective cohort study was conducted with 94 toddlers (<3 years) and 378 older children (3 to 12 years). Factors including demographics, mechanism of injury, additional injuries, location of trauma, pin configuration, postoperative complications, follow-up time, and compliance with the treatment plan were collected and compared. The study included 94 toddlers (59% girls, 2.11±0.64 years) and 378 older children (48% girls, 6.32±1.89 years), chosen at random, who were treated between 2000 and 2015. Among toddlers, fractures were more likely to occur at home (P<.001) and to be the result of suspected nonaccidental trauma (P<.001). Older children had more additional injuries (P<.001), but were no more likely to have an open fracture (P=.59) or a flexion-type fracture (P=.42). Older children were more likely to undergo open reduction (P=.03), whereas toddlers were more likely to be treated with a medial pin (P<.001). Toddlers experienced more cubitus varus (P<.001) and loss of reduction (P=.02). No difference was found in length of follow-up (P=.83) or compliance with the treatment plan (P=.11). This study provides novel insights into clinical differences between toddlers and older children with Gartland type III fractures. Knowledge of these differences can facilitate the delivery of targeted, age-specific care for patients with type III supracondylar humerus fractures. [Orthopedics. 2020;43(5);e421-e424.].

Leadership perspectives in multidisciplinary team meetings; observational assessment based on the ATLAS instrument in cancer care.

OBJECTIVES: High-quality leadership and chairing skills are central components in team performance during multidisciplinary team (MDT) meetings. We hypothesized that the recently developed A Tumor Leadership Assessment inStrument (ATLAS) could provide relevant information to support more detailed insights into MDT chairing and leadership aspects of relevance for team feedback and targeted improvements. MATERIALS AND METHODS: The observational assessment instrument ATLAS rates chairing and leadership skills during MDT meetings in 12 predefined domains that include e.g. time management, case prioritization, team involvement, discussion climate and clarity of treatment recommendations. We used ATLAS to prospectively assess 33 MDT meetings in neuro-oncology, sarcoma and hepatobiliary cancer. RESULTS: The aspects time management, effective case prioritization and provision of clear treatment plans were found to be well-functioning, whereas facilitatation of case discussions, encouragment of team member contributions, keeping the meeting focused and ability to summarize case discussions showed variable and partly weak results. CONCLUSION: We conclude that the ATLAS instrument effectively captures various aspects of MDT leadership and chairing skills. It may thereby provide relevant information to prioritize initiatives that support and develop effective teamwork and decision-making during MDT meetings.

Surgical resection of osteoid osteoma and osteoblastoma of the spine.

Intraoperative radiographic guidance has traditionally been utilized in orthopedic surgery through 2-D navigation with the C-arm and recently with 3-D navigation with the O-arm. The aim of this study was to describe the outcome of surgical treatment of spinal osteoblastoma and osteoid osteoma with the utilization of the O-arm and conventional C-arm guidance. This is a retrospective cohort study of patients with spinal osteoid osteoma and or osteoblastoma who were treated at our institution between 2002 and 2011. Seventeen patients were examined in this study including seven with spinal osteoblastoma and 10 with spinal osteoid osteoma. The mean age of the patients at surgery was 11.5±3.9 years. The O-arm was used in seven patients and the C-arm in 10 patients. The C-arm failed to identify the tumor in one case and needed transport to perform a computed tomographic-scan. The length of surgery was shorter when the O-arm was used, especially in the osteoblastoma group. Thirteen patients were pain free at the last follow-up visit and two patients developed recurrence. Radiographs at the last follow-up did not show signs of vertebral instability following tumor resection. Safe and effective localization of spine tumors and confirmation of tumor removal during surgery was achieved by intraoperative radiographic guidance specifically with the O-arm 3-D navigation system. LEVEL OF EVIDENCE: III.