![David G. Mohler, MD](https://profiles.stanford.edu/proxy/api/cap/profiles/7104/resources/profilephoto/350x350.1509499384455.jpg)
David G. Mohler, MD
Clinical Professor, Orthopaedic Surgery
Web page: http://web.stanford.edu/people/dmohler
Clinical Focus
- Sarcomas
- Orthopaedic Surgery
Administrative Appointments
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Chief, Musculoskeletal Tumor Service (2005 - Present)
Honors & Awards
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Alpha Omega Alpha, Honor Medical Society (1983)
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National Research Service Award, NIH (1987)
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Saul Halpern, MD Orthopaedic Educator Award, Surgery Stanford University School of Medicine (2007)
Professional Education
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Residency: Hospital For Special Surgery Hand Surgery Fellowship (1988) NY
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Internship: UCLA General Surgery Residency (1984) CA
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Medical Education: Weill Cornell Medical College (1983) NY
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Fellowship: Memorial Sloan-Kettering Cancer Center (1989) NY
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Board Certification: American Board of Orthopaedic Surgery, Orthopaedic Surgery (1991)
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MD, Memorial Sloan-Kettering, Bone Disease/Bone Tumor (1989)
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MD, Hospital for Special Surgery, Orthopaedic Surgery (1988)
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MD, UCLA, General Surgery (1984)
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MD, Cornell Univ. Medical College, Medicine (1983)
Current Research and Scholarly Interests
Dr. Mohler is involved in gene expression in sarcomas, and innovative anatomy-preserving surgical management of low grade chondrosarcomas.
2023-24 Courses
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Independent Studies (5)
- Directed Reading in Orthopedic Surgery
ORTHO 299 (Aut, Win, Spr, Sum) - Early Clinical Experience in Orthopedic Surgery
ORTHO 280 (Aut, Win, Spr, Sum) - Graduate Research
ORTHO 399 (Aut, Win, Spr, Sum) - Medical Scholars Research
ORTHO 370 (Aut, Win, Spr, Sum) - Undergraduate Research
ORTHO 199 (Aut, Win, Spr, Sum)
- Directed Reading in Orthopedic Surgery
All Publications
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Sarcoma microenvironment cell states and ecosystems are associated with prognosis and predict response to immunotherapy.
Nature cancer
2024
Abstract
Characterization of the diverse malignant and stromal cell states that make up soft tissue sarcomas and their correlation with patient outcomes has proven difficult using fixed clinical specimens. Here, we employed EcoTyper, a machine-learning framework, to identify the fundamental cell states and cellular ecosystems that make up sarcomas on a large scale using bulk transcriptomes with clinical annotations. We identified and validated 23 sarcoma-specific, transcriptionally defined cell states, many of which were highly prognostic of patient outcomes across independent datasets. We discovered three conserved cellular communities or ecotypes associated with underlying genomic alterations and distinct clinical outcomes. We show that one ecotype defined by tumor-associated macrophages and epithelial-like malignant cells predicts response to immune-checkpoint inhibition but not chemotherapy and validate our findings in an independent cohort. Our results may enable identification of patients with soft tissue sarcomas who could benefit from immunotherapy and help develop new therapeutic strategies.
View details for DOI 10.1038/s43018-024-00743-y
View details for PubMedID 38429415
View details for PubMedCentralID 4486342
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Patterns of local recurrence and risk of skin recurrence in soft tissue sarcomas after surgical resection.
Practical radiation oncology
2023
Abstract
Although there is a theoretical risk of skin seeding during surgical resection of soft tissues sarcomas (STSs), current consensus guidelines recommend against routine use of bolus during RT. However, the risk of skin recurrence has not been systematically assessed. We aimed to assess the patterns of local recurrence (LR) in patients with STS treated with surgery with or without RT.We performed a retrospective analysis of adults with STSs evaluated at our institution between 2007-2021. For patients who developed LR, the depth was evaluated. Progression free survival (PFS) and overall survival (OS) were analyzed from time of first LR using Kaplan-Meier method. Cumulative incidence of distant metastasis (CIDM) was calculated with competing risk analysis from date of LR.Of the 206 patients evaluated, 20 had LR (9.7%). Among patients with LR, five patients (25.0%) were treated with surgery alone and 15 patients (75.0%) with surgery and RT. In patients treated with RT, 46.7% had pre-operative RT, 53.3% had post operative RT, and bolus was used in 46.7%. Surgical margins were close (<1mm) in 4 patients (20.0%) and positive in 10 patients (50.0%). LR occurred in the deep subfascial tissue in 9 patients (45%), subcutaneous tissue in 10 patients (50.0%), and skin in 1 patient (5.0%). The patient with a skin recurrence was treated with surgery alone and the tumor involved the skin at presentation. In patients treated with RT, LR occurred within RT field in 13 patients (86.7%). At 1 year after LR, PFS was 70.3%, OS was 81.7%, and CIDM was 5.9%.Skin recurrences were rare after surgical resection of STSs, and only occurred in a tumor that involved the skin at initial presentation. These findings support current recommendations against routine use of bolus in STSs not involving the skin at presentation.
View details for DOI 10.1016/j.prro.2023.09.006
View details for PubMedID 37804883
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Osteosarcoma PDX-Derived Cell Line Models for Preclinical Drug Evaluation Demonstrate Metastasis Inhibition by Dinaciclib through a Genome-Targeted Approach.
Clinical cancer research : an official journal of the American Association for Cancer Research
2023: OF1-OF16
Abstract
Models to study metastatic disease in rare cancers are needed to advance preclinical therapeutics and to gain insight into disease biology. Osteosarcoma is a rare cancer with a complex genomic landscape in which outcomes for patients with metastatic disease are poor. As osteosarcoma genomes are highly heterogeneous, multiple models are needed to fully elucidate key aspects of disease biology and to recapitulate clinically relevant phenotypes.Matched patient samples, patient-derived xenografts (PDX), and PDX-derived cell lines were comprehensively evaluated using whole-genome sequencing and RNA sequencing. The in vivo metastatic phenotype of the PDX-derived cell lines was characterized in both an intravenous and an orthotopic murine model. As a proof-of-concept study, we tested the preclinical effectiveness of a cyclin-dependent kinase inhibitor on the growth of metastatic tumors in an orthotopic amputation model.PDXs and PDX-derived cell lines largely maintained the expression profiles of the patient from which they were derived despite the emergence of whole-genome duplication in a subset of cell lines. The cell lines were heterogeneous in their metastatic capacity, and heterogeneous tissue tropism was observed in both intravenous and orthotopic models. Single-agent dinaciclib was effective at dramatically reducing the metastatic burden.The variation in metastasis predilection sites between osteosarcoma PDX-derived cell lines demonstrates their ability to recapitulate the spectrum of the disease observed in patients. We describe here a panel of new osteosarcoma PDX-derived cell lines that we believe will be of wide use to the osteosarcoma research community.
View details for DOI 10.1158/1078-0432.CCR-23-0873
View details for PubMedID 37703185
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An osteoinductive and biodegradable intramedullary implant accelerates bone healing and mitigates complications of bone transport in male rats.
Nature communications
2023; 14 (1): 4455
Abstract
Bone transport is a surgery-driven procedure for the treatment of large bone defects. However, challenging complications include prolonged consolidation, docking site nonunion and pin tract infection. Here, we develop an osteoinductive and biodegradable intramedullary implant by a hybrid tissue engineering construct technique to enable sustained delivery of bone morphogenetic protein-2 as an adjunctive therapy. In a male rat bone transport model, the eluting bone morphogenetic protein-2 from the implants accelerates bone formation and remodeling, leading to early bony fusion as shown by imaging, mechanical testing, histological analysis, and microarray assays. Moreover, no pin tract infection but tight osseointegration are observed. In contrast, conventional treatments show higher proportion of docking site nonunion and pin tract infection. The findings of this study demonstrate that the novel intramedullary implant holds great promise for advancing bone transport techniques by promoting bone regeneration and reducing complications in the treatment of bone defects.
View details for DOI 10.1038/s41467-023-40149-5
View details for PubMedID 37488113
View details for PubMedCentralID 5935655
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Long-term Outcomes of Diffuse or Recurrent Tenosynovial Giant Cell Tumor Treated with Postoperative External Beam Radiation Therapy.
Practical radiation oncology
2022
Abstract
PURPOSE: Tenosynovial giant cell tumor (TGCT) is a rare proliferative disorder of synovial membrane that previously was known as pigmented villonodular synovitis (PVNS). Primary treatment involves surgical resection, however, complete removal of all disease involvement is difficult to achieve. Radiation may be useful to reduce the risk of recurrence. We report and update our institutional experience treating diffuse and recurrent TGCT with postsurgical external beam radiation therapy.METHODS AND MATERIALS: We performed a retrospective chart review of 30 patients with TGCT from 2003-2019 treated with radiation therapy. Each patient was evaluated for demographics, radiation treatment parameters, surgical management, complications, and outcome.RESULTS: With mean follow-up of 82 months (range 3-211), 24 patients (80%) who underwent surgery followed by radiation therapy did not experience any further relapse, and all 30 patients achieved local control (100%) with additional salvage therapy following radiotherapy. The most common site of disease was the knee (n=22, 73%), followed by the ankle (n=5, 16%) and the hand (n=3, 10%). Seven patients (24%) presented at time of initial diagnosis while 23 (76%) presented with recurrent disease following surgical resection, with an average of 2.6 surgical procedures prior to radiotherapy. Following resection, 18/30 patients (67%) demonstrated residual TGCT by imaging. The median radiotherapy dose delivered was 36 Gy (range, 34-36 Gy) in 1.8-2.5 Gy/fractions over 4 weeks. In the assessment of post-treatment joint function, 26 sites (86%) exhibited excellent or good function, 2 (7%) fair, and 2 poor (7%) as determined by our scoring system. There were no cases of radiation-associated malignancy.CONCLUSIONS: Among patients with diffuse or recurrent TGCT, postsurgical external beam radiation therapy provided excellent local control and good functional status, with minimal treatment-related complications. Post-surgical radiation therapy is a well-tolerated noninvasive treatment that should be considered following maximal cytoreductive resection to prevent disease progression and recurrence.
View details for DOI 10.1016/j.prro.2022.11.004
View details for PubMedID 36460182
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Survival and failure modes of the Compress spindle and expandable distal femur endoprosthesis among pediatric patients: A multi-institutional study.
Journal of surgical oncology
2022
Abstract
BACKGROUND: Expandable endoprostheses can be used to equalize limb length for pediatric patients requiring reconstruction following large bony oncologic resections. Outcomes of the Compress Compliant Pre-Stress (CPS) spindle paired with an Orthopedic Salvage Systemexpandable distal femur endoprosthesis have not been reported.METHODS: We conducted a multi-institutional retrospective study of pediatric patients with distal femoral bone sarcomas reconstructed with the above endoprostheses. Statistical analysis utilized Kaplan-Meier survival technique and competing risk analysis.RESULTS: Thirty-six patients were included from five institutions. Spindle survivorship was 86.3% (95% confidence interval [CI], 67.7-93.5) at 10 years. Two patients had a failure of osseointegration (5.7%), both within 12 months. Twenty-two (59%) patients had 70 lengthening procedures, with mean expansions of 3.2cm (range: 1-9) over 3.4 surgeries. The expandable mechanism failed in eight patients with a cumulative incidence of 16.1% (95% CI,5.6-31.5) at 5 years. Twenty-nine patients sustained International Society of Limb Salvagefailures requiring 63 unplanned surgeries. Periprosthetic joint infectionoccurred in six patients (16.7%). Limb preservation rate was 91% at 10years.CONCLUSIONS: There is a high rate of osseointegration of the Compress spindle among pediatric patients when coupled with an expandable implant. However, there is a high rate of expansion mechanism failure and prosthetic joint infections requiring revision surgery.LEVEL OF EVIDENCE: Level IV, therapeutic study.
View details for DOI 10.1002/jso.27094
View details for PubMedID 36112398
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Interactions in CSF1-driven Tenosynovial Giant Cell Tumors.
Clinical cancer research : an official journal of the American Association for Cancer Research
2022
Abstract
A major component of cells in Tenosynovial Giant Cell Tumor (TGCT) consists of bystander macrophages responding to CSF1 that is overproduced by a small number of neoplastic cells with a chromosomal translocation involving the CSF1 gene. An autocrine loop was postulated where the neoplastic cells would be stimulated through CSF1R expressed on their surface. Here we use single cell RNA sequencing to investigate cellular interactions in TGCT.A total of 18,788 single cells from three TGCT and two Giant Cell Tumor of Bone (GCTB) samples underwent singe cell RNAseq. The three TGCTs were additionally analyzed using long read RNA sequencing. Immunofluorescence and immunohistochemistry for a range of markers was used to validate and extend the scRNAseq findings.Two recurrent neoplastic cell populations were identified in TGCT that are highly similar to non-neoplastic synoviocytes. We identified GFPT2 as a marker that highlights the neoplastic cells in TCGT. We show that the neoplastic cells themselves do not express CSF1R. We identified overlapping features between the giant cells in TGCT and GCTB.The neoplastic cells in TGCT are highly similar non-neoplastic synoviocytes. The lack of CSF1R on the neoplastic cells indicates they may be unaffected by current therapies. High expression of GFPT2 in the neoplastic cells is associated with activation of the YAP1/TAZ pathway. In addition, we identified expression of the PDGF receptor in the neoplastic cells. These findings suggest two additional pathways to target in this tumor.
View details for DOI 10.1158/1078-0432.CCR-22-1898
View details for PubMedID 36007098
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Management of Patients with Newly Diagnosed Desmoid Tumors in a First-Line Setting.
Cancers
2022; 14 (16)
Abstract
The initial management of desmoid tumors (DTs) is shifting from surgery towards active surveillance, with systemic and locally ablative treatments reserved for enlarging and/or symptomatic disease. However, it remains unclear which patients would benefit most from an initial conservative rather than interventional approach. To answer this question, we retrospectively analyzed adult and pediatric patients with DTs treated at a tertiary academic cancer center between 1992 and 2022. Outcomes measured were progression-free survival (PFS) and time to next treatment (TTNT) after first-line therapy. A total of 262 treatment-naïve patients were eligible for analysis with a median age of 36.5 years (range, 0-87 years). The 5-year PFS and the median TTNT (months) after first-line treatment were, respectively: 50.6% and 69.1 mo for surgery; 64.9% and 149.5 mo for surgery plus adjuvant radiotherapy; 57.1% and 44.7 mo for surgery plus adjuvant systemic therapy; 24.9% and 4.4 mo for chemotherapy; 26.7% and 5.3 mo for hormonal therapy; 41.3% and 29.6 mo for tyrosine kinase inhibitors (TKIs); 44.4% and 8.9 mo for cryoablation and high intensity focused ultrasound; and 43.1% and 32.7 mo for active surveillance. Age ≤ 40 years (p < 0.001), DTs involving the extremities (p < 0.001), a maximum tumor diameter > 60 mm (p = 0.04), and hormonal therapy (p = 0.03) predicted a higher risk of progression. Overall, our results suggest that active surveillance should be considered initially for patients with smaller asymptomatic DTs, while upfront TKIs, local ablation, and surgery achieve similar outcomes in those with more aggressive disease.
View details for DOI 10.3390/cancers14163907
View details for PubMedID 36010900
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Metastatic Pattern of Truncal and Extremity Leiomyosarcoma: Retrospective Analysis of Predictors, Outcomes, and Detection.
Journal of personalized medicine
2022; 12 (3)
Abstract
Leiomyosarcomas (LMS) are a heterogenous group of malignant mesenchymal neoplasms with smooth muscle origin and are classified as either non-uterine (NULMS) or uterine (ULMS). Metastatic pattern, prognostic factors, and ideal staging/surveillance studies for truncal and extremity LMS have not been defined. A retrospective analysis of patients diagnosed with histopathology-confirmed truncal or extremity LMS between 2009 and 2019 was conducted. Data collected included demographics, tumor characteristics, staging, surveillance, and survival endpoints. The primary site was defined as: (1) extremity, (2) flank/Pelvis, or (3) chest wall/Spine. We identified 73 patients, 23.3% of which had metastatic LMS at primary diagnosis, while 68.5% developed metastatic disease at any point. The mean metastatic-free survival from primary diagnosis of localized LMS was 3.0 ± 2.8 years. Analysis of prognostic factors revealed that greater age (≥50 years) at initial diagnosis (OR = 3.74, p = 0.0003), higher tumor differentiation scores (OR = 12.09, p = 0.002), and higher tumor necrosis scores (OR = 3.65, p = 0.026) were significantly associated with metastases. Older patients (≥50 years, OR = 4.76, p = 0.017), patients with larger tumors (≥5 cm or ≥10 cm, OR = 2.12, p = 0.02, OR = 1.92, p = 0.029, respectively), higher differentiation scores (OR = 15.92, p = 0.013), and higher necrosis scores (OR = 4.68, p = 0.044) show worse survival outcomes. Analysis of imaging modality during initial staging and during surveillance showed greater tumor detection frequency when PET imaging was employed, compared to CT imaging (p < 0.0001). In conclusion, truncal and peripheral extremity LMS is an aggressive tumor with high metastatic potential and mortality. While there is a significant risk of metastases to lungs, extra-pulmonary tumors are relatively frequent, and broad surveillance may be warranted.
View details for DOI 10.3390/jpm12030345
View details for PubMedID 35330345
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Detection of MDM2 amplification by shallow whole genome sequencing of cell-free DNA of patients with dedifferentiated liposarcoma.
PloS one
2022; 17 (1): e0262272
Abstract
High-level amplification of MDM2 and other genes in the 12q13-15 locus is a hallmark genetic feature of well-differentiated and dedifferentiated liposarcomas (WDLPS and DDLPS, respectively). Detection of this genomic aberration in plasma cell-free DNA may be a clinically useful assay for non-invasive distinction between these liposarcomas and other retroperitoneal tumors in differential diagnosis, and might be useful for the early detection of disease recurrence. In this study, we performed shallow whole genome sequencing of cell-free DNA extracted from 10 plasma samples from 3 patients with DDLPS and 1 patient with WDLPS. In addition, we studied 31 plasma samples from 11 patients with other types of soft tissue tumors. We detected MDM2 amplification in cell-free DNA of 2 of 3 patients with DDLPS. By applying a genome-wide approach to the analysis of cell-free DNA, we also detected amplification of other genes that are known to be recurrently affected in DDLPS. Based on the analysis of one patient with DDLPS with longitudinal plasma samples available, we show that tracking MDM2 amplification in cell-free DNA may be potentially useful for evaluation of response to treatment. The patient with WDLPS and patients with other soft tissue tumors in differential diagnosis were negative for the MDM2 amplification in cell-free DNA. In summary, we demonstrate the feasibility of detecting amplification of MDM2 and other DDLPS-associated genes in plasma cell-free DNA using technology that is already routinely applied for other clinical indications. Our results may have clinical implications for improved diagnosis and surveillance of patients with retroperitoneal tumors.
View details for DOI 10.1371/journal.pone.0262272
View details for PubMedID 34986184
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Anti-rotation pins for the compress implant do not increase risk of mechanical failure or impair osseointegration
ANNALS OF JOINT
2019; 4 (8)
View details for DOI 10.21037/aoj.2019.08.02
View details for Web of Science ID 000485117900002
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The Outcome of Patients With Localized Undifferentiated Pleomorphic Sarcoma of the Lower Extremity Treated at Stanford University
AMERICAN JOURNAL OF CLINICAL ONCOLOGY-CANCER CLINICAL TRIALS
2019; 42 (2): 166–71
View details for DOI 10.1097/COC.0000000000000496
View details for Web of Science ID 000465420000010
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Genome-Informed Targeted Therapy for Osteosarcoma
CANCER DISCOVERY
2019; 9 (1): 46–63
View details for DOI 10.1158/2159-8290.CD-17-1152
View details for Web of Science ID 000455598900022
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Cervical erector spinae plane block catheter using a thoracic approach: an alternative to brachial plexus blockade for forequarter amputation
CANADIAN JOURNAL OF ANESTHESIA-JOURNAL CANADIEN D ANESTHESIE
2019; 66 (1): 119–20
View details for DOI 10.1007/s12630-018-1170-7
View details for Web of Science ID 000454649300014
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The Outcome of Patients With Localized Undifferentiated Pleomorphic Sarcoma of the Lower Extremity Treated at Stanford University.
American journal of clinical oncology
2018
Abstract
BACKGROUND: As a diagnosis of exclusion, Undifferentiated Pleomorphic Sarcoma (UPS) has unclear clinical characteristics. The objective of this retrospective cohort study is to investigate which clinical and prognostic factors of primary lower-extremity UPS will determine failure.METHODS: We retrospectively reviewed 55 primary lower-extremity UPS cases treated at Stanford between 1998 and 2015. Overall Survival (OS) and Disease-Free Survival (DFS) curves were calculated. Univariate Fisher's Exact Tests were used to examine relationships between disease recurrence, treatment, patient factors, tumor characteristics, and surgical margins.RESULTS: 5-year DFS and OS rates were 60% (95% CI, 45%-72%) and 68% (95% CI, 53%-79%), respectively. The 5-year DFS rate for patients with positive margins was 33.3% (95% CI, 5%-68%) compared with 63% (95% CI, 47%-76%) for patients with negative margins. (Log-rank, P=0.03). The OS rate for those with disease recurrence was 42% % (95% CI, 16%-67%) compared with 76% (95% CI, 59%-87%) for patients who did not have disease recurrence (log-rank, P=0.021). Local failure occurred more frequently with omission of radiation therapy (Fisher's exact test, P=0.009).CONCLUSIONS: Positive surgical margins are an important prognostic factor for predicting relapse in UPS. Relapse of any kind led to worse OS. Radiation therapy improved local control of disease but had no statistically significant effect on DFS, highlighting the need for improved diagnostics to identify those at highest risk for hematogenous metastasis and for selection of patients for adjuvant systemic treatment.
View details for PubMedID 30557163
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Genome-Informed Targeted Therapy for Osteosarcoma.
Cancer discovery
2018
Abstract
Osteosarcoma (OS) is a highly aggressive cancer for which treatment has remained essentially unchanged for over 30 years. OS is characterized by widespread and recurrent somatic copy-number alterations (SCNAs) and structural rearrangements. In contrast, few recurrent point mutations in protein-coding genes have been identified, suggesting that genes within SCNAs are key oncogenic drivers in this disease. SCNAs and structural rearrangements are highly heterogeneous across OS cases, suggesting the need for a genome-informed approach to targeted therapy. To identify patient-specific candidate drivers, we used a simple heuristic based on degree and rank order of copy number amplification (identified by Whole Genome Sequencing) and changes in gene expression as identified by RNAseq. Using patient-derived tumor xenografts, we demonstrate that targeting of patient-specific somatic copy number alterations leads to significant decrease in tumor burden, providing a roadmap for genome-informed treatment of OS.
View details for PubMedID 30266815
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Cervical erector spinae plane block catheter using a thoracic approach: an alternative to brachial plexus blockade for forequarter amputation.
Canadian journal of anaesthesia = Journal canadien d'anesthesie
2018
View details for PubMedID 29868941
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Extraskeletal osteosarcoma of the hand: the role of marginal excision and adjuvant radiation therapy.
Hand (New York, N.Y.)
2015; 10 (4): 602-606
Abstract
Extraskeletal osteosarcoma of the hand is rare, and its optimal modality of local control is not currently known.A literature search was performed to identify studies that describe the treatment and outcomes of extraskeletal osteosarcoma. A second literature search was performed to identify studies that describe the treatment and outcomes of extraskeletal osteosarcoma of the hand specifically.The role of adjuvant radiation for extraskeletal osteosarcoma is not well defined. All cases in the literature describing treatment of extraskeletal osteosarcoma of the hand utilized amputation, and none of the patients described received radiation therapy. However, there are multiple reports showing excellent local control, minimal toxicity, and superior functional outcome with limb conservation and radiation rather than amputation of the hand in pediatric and adult soft tissue sarcoma.For extraskeletal osteosarcoma of the hand, we recommend a treatment approach with the goal of preservation of form and function using limb-sparing surgery and planned postoperative radiation.
View details for DOI 10.1007/s11552-015-9760-0
View details for PubMedID 26568711
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Sarcoma Resection With and Without Vascular Reconstruction: A Matched Case-control Study
ANNALS OF SURGERY
2015; 262 (4): 632-640
Abstract
To examine the impact of major vascular resection on sarcoma resection outcomes.En bloc resection and reconstruction of involved vessels is being increasingly performed during sarcoma surgery; however, the perioperative and oncologic outcomes of this strategy are not well described.Patients undergoing sarcoma resection with (VASC) and without (NO-VASC) vascular reconstruction were 1:2 matched on anatomic site, histology, grade, size, synchronous metastasis, and primary (vs. repeat) resection. R2 resections were excluded. Endpoints included perioperative morbidity, mortality, local recurrence, and survival.From 2000 to 2014, 50 sarcoma patients underwent VASC resection. These were matched with 100 NO-VASC patients having similar clinicopathologic characteristics. The rates of any complication (74% vs. 44%, P = 0.002), grade 3 or higher complication (38% vs. 18%, P = 0.024), and transfusion (66% vs. 33%, P < 0.001) were all more common in the VASC group. Thirty-day (2% vs. 0%, P = 0.30) or 90-day mortality (6% vs. 2%, P = 0.24) were not significantly higher. Local recurrence (5-year, 51% vs. 54%, P = 0.11) and overall survival after resection (5-year, 59% vs. 53%, P = 0.67) were similar between the 2 groups. Within the VASC group, overall survival was not affected by the type of vessel involved (artery vs. vein) or the presence of histology-proven vessel wall invasion.Vascular resection and reconstruction during sarcoma resection significantly increases perioperative morbidity and requires meticulous preoperative multidisciplinary planning. However, the oncologic outcome appears equivalent to cases without major vascular involvement. The anticipated need for vascular resection and reconstruction should not be a contraindication to sarcoma resection.
View details for DOI 10.1097/SLA.0000000000001455
View details for Web of Science ID 000367999800009
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Sarcoma Resection With and Without Vascular Reconstruction: A Matched Case-control Study.
Annals of surgery
2015; 262 (4): 632-40
Abstract
To examine the impact of major vascular resection on sarcoma resection outcomes.En bloc resection and reconstruction of involved vessels is being increasingly performed during sarcoma surgery; however, the perioperative and oncologic outcomes of this strategy are not well described.Patients undergoing sarcoma resection with (VASC) and without (NO-VASC) vascular reconstruction were 1:2 matched on anatomic site, histology, grade, size, synchronous metastasis, and primary (vs. repeat) resection. R2 resections were excluded. Endpoints included perioperative morbidity, mortality, local recurrence, and survival.From 2000 to 2014, 50 sarcoma patients underwent VASC resection. These were matched with 100 NO-VASC patients having similar clinicopathologic characteristics. The rates of any complication (74% vs. 44%, P = 0.002), grade 3 or higher complication (38% vs. 18%, P = 0.024), and transfusion (66% vs. 33%, P < 0.001) were all more common in the VASC group. Thirty-day (2% vs. 0%, P = 0.30) or 90-day mortality (6% vs. 2%, P = 0.24) were not significantly higher. Local recurrence (5-year, 51% vs. 54%, P = 0.11) and overall survival after resection (5-year, 59% vs. 53%, P = 0.67) were similar between the 2 groups. Within the VASC group, overall survival was not affected by the type of vessel involved (artery vs. vein) or the presence of histology-proven vessel wall invasion.Vascular resection and reconstruction during sarcoma resection significantly increases perioperative morbidity and requires meticulous preoperative multidisciplinary planning. However, the oncologic outcome appears equivalent to cases without major vascular involvement. The anticipated need for vascular resection and reconstruction should not be a contraindication to sarcoma resection.
View details for DOI 10.1097/SLA.0000000000001455
View details for PubMedID 26366542
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Antirotation Pins Improve Stability of the Compress Limb Salvage Implant: A Biomechanical Study
CLINICAL ORTHOPAEDICS AND RELATED RESEARCH
2014; 472 (12): 3982-3986
Abstract
Limb salvage implants that rely on compliant compression osseointegration to achieve bone fixation may achieve longer survivorship rates compared with traditional cemented or press-fit stemmed implants; however, failures resulting from rotational instability have been reported. The effect of using antirotation pins on the rotational stability of the fixation has not been well studied.We asked the following question: When tested in a cadaver model, does the use of antirotation pins increase the torque required to cause implant failure or rotation?Thirty-two cadaver femurs were divided into four groups of eight femurs. We compared the torque to failure among groups containing zero, one, two, three, and four pins using a servohydraulic testing device.Adding antirotation pins increased the torque required to cause failure (R(2) = 0.77; p < 0.001). This increase was most notable in groups comparing zero pins with one pin (14 N-m, [95% CI, 10.9-17.1] versus 23 N-m, [95% CI 22.5-23.48]; p = 0.01) and two compared with three pins (29 N-m, [95% CI, 21.7-36.3] versus 42 N-m, [95% CI, 37.8-46.2]; p = 0.35).It appears that the use of antirotation pins improves rotational stability of the compliant compression endoprosthesis. Although these findings need to be verified in a clinical study, the addition of antirotation pins may improve osteointegration and we have changed our practice to use a minimum of three antirotation pins when implanting this device.Improvements in implant technology and surgical techniques may lead to improved clinical outcomes and patient quality of life. Addition of antirotation pins appears to improve implant stability and may decrease the need for revision surgery.
View details for DOI 10.1007/s11999-014-3899-9
View details for Web of Science ID 000344647200052
View details for PubMedCentralID PMC4397809
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Antirotation pins improve stability of the compress limb salvage implant: a biomechanical study.
Clinical orthopaedics and related research
2014; 472 (12): 3982-3986
Abstract
Limb salvage implants that rely on compliant compression osseointegration to achieve bone fixation may achieve longer survivorship rates compared with traditional cemented or press-fit stemmed implants; however, failures resulting from rotational instability have been reported. The effect of using antirotation pins on the rotational stability of the fixation has not been well studied.We asked the following question: When tested in a cadaver model, does the use of antirotation pins increase the torque required to cause implant failure or rotation?Thirty-two cadaver femurs were divided into four groups of eight femurs. We compared the torque to failure among groups containing zero, one, two, three, and four pins using a servohydraulic testing device.Adding antirotation pins increased the torque required to cause failure (R(2) = 0.77; p < 0.001). This increase was most notable in groups comparing zero pins with one pin (14 N-m, [95% CI, 10.9-17.1] versus 23 N-m, [95% CI 22.5-23.48]; p = 0.01) and two compared with three pins (29 N-m, [95% CI, 21.7-36.3] versus 42 N-m, [95% CI, 37.8-46.2]; p = 0.35).It appears that the use of antirotation pins improves rotational stability of the compliant compression endoprosthesis. Although these findings need to be verified in a clinical study, the addition of antirotation pins may improve osteointegration and we have changed our practice to use a minimum of three antirotation pins when implanting this device.Improvements in implant technology and surgical techniques may lead to improved clinical outcomes and patient quality of life. Addition of antirotation pins appears to improve implant stability and may decrease the need for revision surgery.
View details for DOI 10.1007/s11999-014-3899-9
View details for PubMedID 25209342
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Successful Limb Salvage of a "Too-Short Segment" of the Proximal Part of the Femur with Use of a Compression Osseointegration Implant: A Case Report.
JBJS case connector
2014; 4 (3): e63–e6
View details for PubMedID 29252502
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Surgical Technique: Methods for Removing a Compress (R) Compliant Prestress Implant
CLINICAL ORTHOPAEDICS AND RELATED RESEARCH
2012; 470 (4): 1204-1212
Abstract
The Compress® device uses a unique design using compressive forces to achieve bone ingrowth on the prosthesis. Because of its design, removal of this device may require special techniques to preserve host bone. DESCRIPTION OF TECHNIQUES: Techniques needed include removal of a small amount of bone to relieve compressive forces, use of a pin extractor and/or Kirschner wires for removal of transfixation pins, and creation of a cortical window in the diaphysis to gain access to bone preventing removal of the anchor plug.We retrospectively reviewed the records of 63 patients receiving a Compress® device from 1996 to 2011 and identified 11 patients who underwent subsequent prosthesis removal. The minimum followup was 1 month (average, 20 months; range, 1-80 months). The most common reason for removal was infection (eight patients) and the most common underlying diagnosis was osteosarcoma (five patients). Three patients underwent above-knee amputation, whereas the others (eight patients) had further limb salvage procedures at the time of prosthesis removal.Five patients had additional unplanned surgeries after explantation. Irrigation and débridement of the surgical wound was the most common unplanned procedure followed by latissimus free flap and hip prosthesis dislocation. At the time of followup, all patients were ambulating on either salvaged extremities or prostheses.Although removal of the Compress® device presents unique challenges, we describe techniques to address those challenges.
View details for DOI 10.1007/s11999-011-2128-z
View details for PubMedID 22002827
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Curettage and Cryosurgery for Low-grade Cartilage Tumors Is Associated with Low Recurrence and High Function
CLINICAL ORTHOPAEDICS AND RELATED RESEARCH
2010; 468 (10): 2765-2773
Abstract
Chondrosarcomas of bone traditionally have been treated by wide or radical excision, procedures that may result in considerable lifelong disability. Grade 1 chondrosarcomas have little or no metastatic potential and are often difficult to distinguish from painful benign enchondromas. Curettage with adjuvant cryosurgery has been proposed as an alternative therapy for Grade 1 chondrosarcomas given the generally better function after the procedure. However, because it is an intralesional procedure, curettage and cryosurgery may be associated with higher rates of recurrence.We asked whether Grade 1 chondrosarcomas and enchondromas of uncertain malignant potential treated by curettage and cryosurgery are associated with low recurrence rates and high functional scores.We retrospectively reviewed the records of 46 patients with Grade 1 chondrosarcomas and enchondromas of uncertain malignant potential treated by curettage and cryosurgery. Forty-one patients had tumors of the long bones. Patients were followed a minimum of 18 months (average, 47.2. months; range, 18-134 months) for evidence of recurrence and for assessment of Musculoskeletal Tumor Society (MSTS) functional score.Two of the 46 patients had recurrences in the original tumor site (4.3% recurrence rate), which subsequently were removed by wide excision, and both patients were confirmed to be disease-free 36 and 30 months, respectively, after the second surgery. The mean MSTS score was 27.2 of 30 points (median, 29 points).Our observations show curettage with cryosurgery is associated with low recurrence of Grade 1 chondrosarcoma and high functional scores. Curettage with cryosurgery is a reasonable alternative to wide or radical excision as the treatment for Grade 1 chondrosarcomas, and allows for more radical surgery in the event of local recurrence.Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.
View details for DOI 10.1007/s11999-010-1445-y
View details for PubMedID 20574801
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EXTERNAL BEAM RADIATION THERAPY ENHANCES LOCAL CONTROL IN PIGMENTED VILLONODULAR SYNOVITIS
INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS
2009; 75 (1): 183-187
Abstract
Pigmented villonodular synovitis (PVNS) is a rare proliferative disorder of the synovium with locally aggressive behavior. We reviewed our experience using radiation therapy in the treatment of PVNS.Seventeen patients with 18 sites of PVNS were treated with radiation between 1993 and 2007. Cases were retrospectively reviewed for patient information, treatment parameters, complications, and outcome. Seven sites were primary presentations and 11 were recurrent with an average of 2.5 prior surgical interventions. The most common location was the knee joint (67%). Cytoreductive surgery was performed before radiation therapy in 16/18 sites with all having proven or suspected residual disease. Radiation was delivered using 4-15 MV photons with an average total dose 34 Gy (range, 20-36 Gy). Seventeen of 18 sites (94%) had postradiotherapy imaging.With average follow-up of 46 months (range, 8-181 months), initial local control was achieved in 75% (12/16) of the sites with prior cytoreductive surgery (mean time to recurrence, 38 months). Ultimate local control was 100% after repeat resection (mean follow-up, 61 months). Two additional sites without prior cytoreductive surgery showed growth after radiotherapy (mean time to documented growth, 10.5 months). Seventeen of the 18 involved joints (94%) were scored as excellent or good PVNS-related function, one site (5%) as fair function, and no site with poor function. No patient required amputation; and there were no Grade 3/4 treatment-related complications.Postoperative external beam radiation is effective in preventing disease recurrence and should be offered following maximal cytoreduction to enhance local control in PVNS.
View details for DOI 10.1016/j.ijrobp.2008.10.058
View details for Web of Science ID 000269328700031
View details for PubMedID 19211195
- Hunting Injuries In Wilderness Medicine, Editor Auerbach, P. Elsevier Press 2007
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Surgical Treatment of Post-Radiotherapy Nonunions of the Clavicle
BULLETIN OF THE HOSPITAL FOR JOINT DISEASES
2005; 62 (3-4): 125–30
Abstract
Fractures of irradiated bones present special challenges to healing. Nonunions are very common and are challenging surgical problems. We report three radiated nonunions of the clavicle successfully treated with modifications of standard internal fixation techniques.
View details for Web of Science ID 000216347100010
View details for PubMedID 16022226
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Failure of medullary tubes - A materials analysis
INJURY-INTERNATIONAL JOURNAL OF THE CARE OF THE INJURED
2004; 35 (9): 878-882
Abstract
The objective of this study is to determine the effects of autoclaving on the stress, strain, ultimate tensile strength (UTS), fracture strain, modulus, and yield stress of nylon medullary tubes. There are three reports describing nylon medullary tube failure in the literature. All cases involved the use of nylon medullary tubes during open reduction internal fixation of fractured long bones. We demonstrated increased brittleness and decreased strength with increased exposure of medullary tubes to autoclaving, most dramatically after 100 autoclave cycles. Visual inspection of tubes is a clear indication of material degradation after repeated autoclaving. Furthermore, there is a significant difference in ultimate tensile strength (P < 0.0001) between tubes exposed to less than 100 sterilization cycles compared to tubes exposed to greater than 100 cycles. Likewise, there is a significant decrease in yield stress (P < 0.0004) between the same groups. We recommend disposal and replacement of nylon medullary tubes before they are exposed to 100 autoclaving cycles in order to avoid failure of the device.
View details for DOI 10.1016/S0020-1383(03)00307-3
View details for PubMedID 15302240
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Intercalary tibial allografts following tumor resection: The role of fibular centralization
ORTHOPEDICS
2003; 26 (6): 631-637
Abstract
Options to reconstruct intercalary tibial defects include allografts, vascularized bone transfers, autogenous cortical grafts, endoprostheses, and Ilizarov bone transport. Five patients underwent intercalary bulk allograft reconstruction following en bloc resection of tibial sarcomas. Two patients underwent immediate fibular centralization and iliac crest bone grafting in addition to the allograft. Two patients who underwent fibular centralization during primary reconstruction united uneventfully. The remaining three patients developed nonunion, of which one was successfully salvaged by fibular centralization. A combined allograft transplant and fibular centralization with iliac crest bone grafting is an effective procedure to reconstruct the tibial diaphysis, as well as a salvage procedure for allograft nonunion.
View details for PubMedID 12817729
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Multifocal pseudoaneurysmal bone cysts in sickle cell disease
ORTHOPEDICS
2001; 24 (5): 489-491
View details for Web of Science ID 000168761800015
View details for PubMedID 11379999
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Multiple fracture of medullary tube during intramedullary nailing of long bone fractures
JOURNAL OF ORTHOPAEDIC TRAUMA
2000; 14 (7): 514-517
Abstract
Intramedullary nailing is an accepted treatment for the fixation of femoral and tibial shaft fractures. There is a low but significant incidence of intraoperative complications during intramedullary nailing. During this procedure, a medullary tube may be used to exchange the bent olive-tipped reaming guidewire for the straight guidewire. A review of the literature found only one report of a fracture of the medullary tube. Two cases in which the medullary tube fractured into multiple pieces are presented.
View details for Web of Science ID 000165097300011
View details for PubMedID 11083617
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Augmented amputations of the lower extremity
CLINICAL ORTHOPAEDICS AND RELATED RESEARCH
2000: 183-197
Abstract
Ten patients who had amputations of a lower extremity for high-grade sarcomas underwent bone augmentation with either allograft or autograft between 1988 and 1996. There were eight transfemoral amputations and two transtibial amputations. The transferred segments consisted of one proximal tibia and six distal tibia autografts, two allografts, one autograft talar dome and first metatarsal, and one with a patellar cap of a supracondylar amputation. The average length of followup was 54 months. There were no nonunions of any of the grafts. There were three wound problems requiring additional operations. One autograft resorbed, and one autograft had a late infection. There was one local recurrence. Augmentation to provide length resulted in a 42% increase in bone length in those performed purely for length. All patients were able to use standard prostheses. Functional outcome was appropriate to the amputation level. Half of the patients avoided more proximal levels of amputation because of the ability to augment the osteotomy. The use of nonvascularized structural autografts or allografts is a simple procedure that can produce a superior residual limb in patients undergoing amputation. Its use should be considered in patients for whom traditional amputation techniques will result in poor function, difficulty in fitting a prosthesis, or greater than necessary anatomic loss.
View details for Web of Science ID 000085397700024
View details for PubMedID 10693566
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Open synovectomy with cryosurgical adjuvant for treatment of diffuse pigmented villonodular synovitis of the knee.
Bulletin (Hospital for Joint Diseases (New York, N.Y.))
2000; 59 (2): 99-105
Abstract
Pigmented villonodular synovitis (PVNS) is an uncommon, benign disorder usually affecting the synovial membrane of large joints. The diffuse form of PVNS is extremely difficult to control, and long-term recurrence inevitably results in arthrodesis or arthroplasty. Current treatments include surgical, chemical, and radiation synovectomy, but all have significant failure rates. In hope of obtaining a more complete synovectomy, we used cryosurgery as an adjuvant to open synovectomy in three patients. Two patients presented with multiple failed arthroscopic synovectomies, and one patient presented with arthroscopically unresectable PVNS. The surgical approach involved take down and repair of the anterior meniscal attachments, and direct entry into the posterior space through medial and lateral femoral capsular attachments. Cryosurgical surface spray was used on all non-cartilaginous surfaces. At follow-up of 14, 30, and 31 months, all three patients remained symptom-free and there were no indications of clinical recurrence. There were no obvious complications or morbidity from the cryosurgical procedure and all patients had excellent functional recovery. All patients returned to sports and their jobs without restrictions. In the past, it has been shown that cryosurgery is a safe and effective treatment modality for proliferative joint disease. We propose the use of adjuvant cryosurgery for PVNS patients selected for open synovectomy.
View details for PubMedID 10983259
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Complete pelvic ring failure after posterior iliac bone graft harvesting
SPINE
1999; 24 (20): 2101-2104
Abstract
Case report.To present a rare complication of posterior iliac bone graft harvesting.Although iliac bone graft harvesting is a common procedure in spinal surgery, it is not without complications. One such complication is fracture of the ilium that is seen most often in older women with osteopenia.In this case a severe complication of posterior iliac bone graft harvesting was identified in a patient with steroid-induced osteoporosis that led to multiple pelvic fracture, nonunions, and eventual failure of the entire pelvic ring. Imaging studies showed osteoporotic bone and multiple nonunions of the pelvis with structural collapse.Staged sequential platings of the iliac wings were performed to stabilize the pelvis. The initial fixation of the left iliac wing apparently united after hardware failure. The right iliac wing was successfully fixed with plates supplemented with bone cement and allograft. Anterior fixation was planned.Care should be taken when considering autograft harvesting in patients with risk factors for osteoporosis. The outcome could be debilitating.
View details for Web of Science ID 000083124400006
View details for PubMedID 10543005
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Angiosarcoma of the hand associated with chronic exposure to polyvinyl chloride pipes and cement. A case report.
journal of bone and joint surgery. American volume
1998; 80 (9): 1349-1354
View details for PubMedID 9759821
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Angiosarcoma of the hand associated with chronic exposure to polyvinyl chloride pipes and cement - A case report
JOURNAL OF BONE AND JOINT SURGERY-AMERICAN VOLUME
1998; 80A (9): 1349-1354
View details for Web of Science ID 000076170600014
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Adamantinoma arising in the distal fibula treated with distal fibulectomy: A case report and review of the literature
FOOT & ANKLE INTERNATIONAL
1997; 18 (11): 746-751
Abstract
Adamantinoma is a rare primary bone tumor occurring in the mandible and the long tubular bones. The diaphysis of the tibia is the most common site of extragnathic presentation. Fibular involvement is rare and usually has coexisting tibial involvement. Adamantinoma arising in the distal fibular metaphysis has not been previously reported. This is a case of a teenage boy presenting with a cystic lesion of the distal fibula, initially diagnosed and treated as a unicameral bone cyst. Aggressive behavior ultimately led to a diagnosis of adamantinoma. He was treated with distal fibulectomy without surgical reconstruction with good functional outcome.
View details for Web of Science ID A1997YF98100012
View details for PubMedID 9391822
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Glomus tumor of the plantar arch: A case report with magnetic resonance imaging findings
FOOT & ANKLE INTERNATIONAL
1997; 18 (10): 672-674
Abstract
A 55-year-old woman with a 12-year history of a painful nodule in the subcutaneous fat layer of the plantar arch was evaluated with magnetic resonance imaging, followed by excisional biopsy. Pathology revealed a glomus tumor, which is extremely rare in the plantar surface of the foot. The magnetic resonance imaging studies are presented. The literature on glomus tumors in the foot is reviewed. This entity should be considered in the differential diagnosis of solitary plantar nodules when marked sensitivity to temperature or pressure is exhibited.
View details for Web of Science ID A1997YB59300014
View details for PubMedID 9347308
- Oncologic and Functional Results of Curettage and Cryosurgical Treatment of Low Grade Chondrosarcomas Clinical Orthopaedics and Related Research. (Accepted 10/2009)