Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Richard Löfvenberg is active.

Publication


Featured researches published by Richard Löfvenberg.


American Journal of Sports Medicine | 1995

Prolonged Reaction Time in Patients with Chronic Lateral Instability of the Ankle

Richard Löfvenberg; Johan Kärrholm; Gunnevi Sundelin; Olof Ahlgren

Impaired proprioception has been suggested as one cause of chronic lateral instability of the ankle. We sub jected 15 ankles in 13 patients with symptoms of chronic lateral instability to sudden angular displacement. The reaction times in the peroneus longus and the tibialis anterior muscles were recorded and compared with those from 15 control ankles. Significantly longer ipsi lateral reaction time was recorded in the patients (65 ms) compared with the controls (49 ms). We concluded that delayed proprioceptive response to sudden angular displacement of the ankle may predispose an individual to or be a cause of chronic lateral instability of the ankle.


Foot & Ankle International | 1994

The Outcome of Nonoperated Patients with Chronic Lateral Instability of the Ankle: A 20-Year Follow-up Study

Richard Löfvenberg; Johan Kärrholm; Björn Lund

Thirty-seven patients conservatively treated because of chronic lateral instability of the ankle were studied 18 to 23 years after their index visit. Twenty-two patients, 12 with unilateral and 10 with bilateral symptoms (32 of 49 ankles), still suffered from instability, but only three considered further treatment Degenerative changes were observed in six of 46 radiographically examined ankles, with no correlation to age or persistent instability.


International Journal of Cancer | 2011

Mesenchymal stromal cells from primary osteosarcoma are non-malignant and strikingly similar to their bone marrow counterparts.

Jan Claas Brune; Ariane Tormin; Maria Johansson; Pehr Rissler; Otte Brosjö; Richard Löfvenberg; Fredrik Vult von Steyern; Fredrik Mertens; Anders Rydholm; Stefan Scheding

Mesenchymal stromal cells (MSC) are multipotent cells that can be isolated from a number of human tissues. In cancer, MSC have been implicated with tumor growth, invasion, metastasis, drug resistance and were even suggested as possible tumor‐initiating cells in osteosarcoma (OS). However, MSC from OS and their possible tumor origin have not yet been thoroughly investigated. Therefore, primary OS mesenchymal progenitors and OS‐derived MSC were studied. OS samples contained very high frequencies of mesenchymal progenitor cells as measured by the colony‐forming unit fibroblast (CFU‐F) assay (median: 1,117 colonies per 105 cells, range: 133–3,000, n = 6). This is considerably higher compared to other human tissues such as normal bone marrow (BM) (1.3 ± 0.2 colonies per 105 cells, n = 8). OS‐derived MSC (OS‐MSC) showed normal MSC morphology and expressed the typical MSC surface marker profile (CD105/CD73/CD90/CD44/HLA‐classI/CD166 positive, CD45/CD34/CD14/CD19/HLA‐DR/CD31 negative). Furthermore, all OS‐MSC samples could be differentiated into the osteogenic lineage, and all but one sample into adipocytes and chondrocytes. Genetic analysis of OS‐MSC as well as OS‐derived spheres showed no tumor‐related chromosomal aberrations. OS‐MSC expression of markers related to tumor‐associated fibroblasts (fibroblast surface protein, alpha‐smooth muscle actin, vimentin) was comparable to BM‐MSC and OS‐MSC growth was considerably affected by tyrosine kinase inhibitors. Taken together, our results demonstrate that normal, non‐malignant mesenchymal stroma cells are isolated from OS when MSC culture techniques are applied. OS‐MSC represent a major constituent of the tumor microenvironment, and they share many properties with BM‐derived MSC.


American Journal of Sports Medicine | 1993

The influence of an ankle orthosis on the talar and calcaneal motions in chronic lateral instability of the ankle A stereophotogrammetric analysis

Richard Löfvenberg; Johan Kärrholm

The mechanical support provided by a semirigid ankle orthosis was tested in 14 ankles with symptoms of chronic lateral instability by use of stereophotogram metric analysis. Talar and calcaneal rotations were measured with and without the Strong ankle orthosis during manual adduction test and adduction test with a predetermined torque (5 N-m). Significant reduction of talar and calcaneal plantar flexion, internal rotation, and varus angulation was noted when the orthosis was applied. The results of this study suggest that the semirigid orthosis may provide enough external support to prevent ankle sprains and to protect ligament recon structions.


Clinical & Experimental Metastasis | 1997

A novel spontaneous metastasis model of human osteosarcoma developed using orthotopic transplantation of intact tumor tissue into tibia of nude mice

Sead Crnalic; Irene Hakansson; Lennart Boquist; Richard Löfvenberg; Lars-Åke Broström

Evaluation of potential new treatment strategies requires adequate experimental tumor models which resemble the clinical situation as closely as possible. The purpose of the present study was to establish a new human osteosarcoma spontaneous metastasis model using orthotopic transplantation of histologically intact tumor tissue into the tibia of nude mice. Intact tumor pieces, obtained from the 32nd serial passage of subcutaneously growing human osteosarcoma xenografts, were implanted into the proximal tibia in 31 nude mice. Animals were sacrificed and autopsied 2, 4, 6, and 8 weeks after transplantation and examined macroscopically and microscopically for local tumor growth and metastases. All mice developed local intratibial bone tumors that were radiographically and histologically similar to primary human osteosarcoma. Lung metastases were observed in all mice, local and distant lymph node metastases in 15 (48%), and liver metastases in 6 (19%) mice. The microscopic appearance of the metastases was similar to that observed in the donor patientÕs tumor, corresponding subcutaneous xenografts and orthotopically transplanted intratibial tumors. This spontaneous metastasis model of human osteosarcoma in nude mice may resemble a clinical situation and could thus be useful for studies on local tumor growth, metastasis formation and therapy.


Spine | 2012

Predicting survival for surgery of metastatic spinal cord compression in prostate cancer: a new score.

Sead Crnalic; Richard Löfvenberg; Anders Bergh; Anders Widmark; Christer Hildingsson

Study Design. We retrospectively analyzed prognostic factors for survival in patients with prostate cancer operated for metastatic spinal cord compression. Objective. The aim was to obtain a clinical score for prediction of survival after surgery. Summary of Background Data. Survival prognosis is important when deciding about treatment of patients with metastatic spinal cord compression. The criteria for identifying patients with prostate cancer who may benefit from surgical treatment are unclear. Methods. The study comprised 68 consecutive patients with prostate cancer operated for metastatic spinal cord compression at Umeå University Hospital, Sweden. The indication for surgery was neurological deficit; 53 patients had hormone-refractory prostate cancer and 15 patients had previously untreated, hormone-naïve prostate cancer. In 42 patients, posterior decompression was performed and 26 patients were operated with posterior decompression and stabilization. Results. A new score for prediction of survival was developed on the basis of the results of survival analyses. The score includes hormone status of prostate cancer, Karnofsky performance status, evidence of visceral metastasis, and preoperative serum prostate-specific antigen (PSA). The total scores ranged from 0 to 6. Three prognostic groups were formulated: group A (n = 32) with scores 0–1; group B (n = 23) with scores 2–4, and group C (n = 12) with scores 5–6. The median overall survival was 3 (0.3–20) months in group A, 16 (1.8–59) months in group B, and more than half (7 of 12) of patients were still alive in group C. Conclusion. We present a new prognostic score for predicting survival of patients with prostate cancer after surgery for metastatic spinal cord compression. The score is easy to apply in clinical practice and may be used as additional support when making decision about treatment.


Acta Orthopaedica | 2012

Outcome after surgery for metastatic spinal cord compression in 54 patients with prostate cancer

Sead Crnalic; Christer Hildingsson; Pernilla Wikström; Anders Bergh; Richard Löfvenberg; Anders Widmark

Background and purpose The criteria for selecting patients who may benefit from surgery of spinal cord compression in metastatic prostate cancer are poorly defined. We therefore studied patients operated for metastatic spinal cord compression in order to evaluate outcome of surgery and to find predictors of survival. Patients and methods We reviewed the records of 54 consecutive patients with metastatic prostate cancer who were operated for spinal cord compression at Umeå University Hospital. The indication for surgery was neurological deficit due to spinal cord compression. 41 patients had hormone-refractory cancer and 13 patients had previously untreated, hormone-naïve prostate cancer. 29 patients were operated with posterior decompression only, and in 25 patients posterior decompression and stabilization was performed. Results Preoperatively, 6/54 of patients were able to walk. 1 month after surgery, 33 patients were walking, 15 were non-ambulatory, and 6 had died. Mortality rate was 11% at 1 month, 41% at 6 months, and 59% at 1 year. In the hormone-naïve group, 8/13 patients were still alive with a median postoperative follow-up of 26 months. In the hormone-refractory group, median survival was 5 months. Patients with hormone-refractory disease and Karnofsky performance status (KPS) of ≤ 60% had median survival of 2.5 months, whereas those with KPS of 70% and KPS of ≥ 80% had a median survival of 7 months and 18 months, respectively (p < 0.001). Visceral metastases were present in 12/41 patients with hormone-refractory tumor at the time of spinal surgery, and their median survival was 4 months—as compared to 10 months in patients without visceral metastases (p = 0.003). Complications within 30 days of surgery occurred in 19/54 patients. Interpretation Our results indicate that patients with hormone-naive disease, and those with hormone-refractory disease with good performance status and lacking visceral metastases, may be helped by surgery for metastatic spinal cord compression.


Acta Orthopaedica Scandinavica | 1999

Clinical course in synovial sarcoma. A Scandinavian sarcoma group study of 104 patients.

Björn Skytting; Henrik C. F. Bauer; Roland Perfekt; Riika Huuhtanen; Thor Alvegård; Örjan Berlin; Pelle Gustafson; Ragnhild Klepp; Richard Löfvenberg; Gunnar Sæter; Clement Trovik; Ola Wahlström

We analyzed treatment and outcome in 104 Scandinavian patients with synovial sarcoma in the extremities or trunk wall, diagnosed between 1986 and 1994. Only surgically treated patients without metastases at diagnosis were included. Median follow-up of survivors was 6 (3-11) years. 34 patients developed metastases. The overall 5- and 7-year survival rates were 0.76 (95% CI 0.66-0.83) and 0.69 (0.58-0.78), respectively. Large tumor size and amputation were significantly associated with impaired metastasis-free survival. Patients with local recurrence had a higher risk of metastases following the local event. Local excision with inadequate margin was associated with a higher risk of local recurrence.


Acta Orthopaedica Scandinavica | 1994

Ligament reconstruction for ankle instability A 5-year prospective RSA follow-up of 30 cases

Richard Löfvenberg; Johan Kärrholm; Olof Ahlgren

30 ankles in 27 patients operated on for chronic lateral instability with tensioning of the lateral ligaments and capsular tissue were examined using RSA preoperatively, at 20 and 60 months. 28 ankles were considered excellent or improved by the patients. Mechanical stability (talar adduction and translation) was increased without compromising the passive range of motions.


Acta Oncologica | 2013

Early diagnosis and treatment is crucial for neurological recovery after surgery for metastatic spinal cord compression in prostate cancer

Sead Crnalic; Christer Hildingsson; Anders Bergh; Anders Widmark; Olle Svensson; Richard Löfvenberg

Abstract Background. Spinal cord compression is an oncological and surgical emergency. Delays in referral and diagnosis may influence functional outcome. It is therefore important to identify patients who will regain or maintain the ability to walk after surgery. The aim of the present study was to examine current practice for referral and diagnosis of prostate cancer patients with spinal cord compression and to identify prognostic factors for neurological outcome after surgery. Patients and methods. The study includes 68 consecutive patients with prostate cancer who underwent surgery due to neurological compromise. Intervals from onset of neurological symptoms to referral, diagnosis, and treatment were analyzed in relation to functional outcome. The prognostic significance of preoperative clinical parameters on gait function one month after surgery was evaluated. Results. Patients who were referred from local hospitals had longer delay to surgery than those who directly presented to the cancer center (p = 0.004). The rate of diagnosis with MRI increased through the week and peaked on Friday, with few patients being diagnosed during weekends. The ability to walk before surgery, hormone-naive prostate cancer, and/or shorter time from loss of ambulation were associated with more favorable neurological outcome. In patients with hormone-refractory disease who were unable to walk before surgery regaining ambulation was associated with: duration of paresis < 48 hours (p = 0.005), good preoperative performance status (p = 0.04), preoperative PSA serum level < 200 ng/ml (p = 0.03), and surgery with posterior decompression and stabilization (p = 0.03). Conclusion. Early diagnosis and rapid treatment of spinal cord compression in prostate cancer patients is crucial for neurological recovery. Raising awareness of the condition among patients at risk and among physicians is of outmost importance as well as improving local and regional guidelines for treatment.

Collaboration


Dive into the Richard Löfvenberg's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge