Amir Oron

Kaplan Medical Center, Yavne, Central District, Israel

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Publications (15)25.38 Total impact

  • Article: The influence of radiofrequency ablation patterns on length, histological and mechanical properties of tendons.
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    ABSTRACT: The use of radiofrequency ablation for thermomodulation of connective tissues has gained acceptance with some surgeons. It is now mainly used for shoulder instability, and two techniques are commonly applied - ablation in a uniform pattern (paintbrush) and ablation in a linearly dispersed fashion (grid). The use of these techniques for shrinkage of tendons or cruciate ligaments is not widely accepted but may be utilized in selected cases. We assessed the effects of thermo-modulation via monopolar radiofrequency ablation using these two techniques on the histological and biomechanical properties of rabbit Achilles tendons. 16 paired rabbit achilles tendons were divided into two treatment groups. Using a Monopolar RF device, eight tendons were treated using the paintbrush technique, and eight using the grid technique. The tendons were shrunk to about 90% of their original length, and the paired tendons were used as control. Following thermomodulation, tendons were pulled to tear using the Instron 4502 (Instron, Mass.) device. We found treated tendons were significantly less resistant to tear when compared to control; the average load to failure of the treatment group was 19.4% lower (p=0.05) than the control group values and the average tissue stiffness in the treatment group was 11.3% lower (p=0.051) than the control group. We found a tendency towards a lower resistance to pull in the tendon group treated using the grid technique. Histological analysis demonstrated areas of collagen denaturation correlated to areas of thermomodulation. A random point of failure was found along the tendons in the paintbrush group whereas the typical point of failure in the grid group was located at the treatment point or at its margins. Our findings demonstrate that use of the grid technique in ablation of tendons creates typical failure points (locus minoris resistenci) which bring about failure and alter the biomechanical properties of the thermomodulated tendons. Thermomodulation of tendons may be used efficiently in selected cases but its detrimental effects to the biomechanical attributes of the tissue should be considered.
    Muscles, ligaments and tendons journal. 04/2012; 2(2):85-90.
  • Article: Enhancement of bony in-growth to metal implants by combining controlled hydroxyapatite coating and heat treatment.
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    ABSTRACT: The rate of bony in-growth to heat-treated and controlled hydroxyapatite metal implants made of either titanium alloy (Ti-6Al-4V) or stainless steel (SS) 316L inserted to the medullar canal of the femur in rats was investigated. It was found that while partial coverage of hydroxyapatite (HA) did not cause a significant elevation of their bonding strength when compared with nonheated implants, HA, and heat treatment caused a significant (p < 0.01) elevation of 3.1-fold in the bonding strength of the implants to the host bone. A similar phenomenon to that found for the titanium alloy implants was found to be true for the SS implants as well. It is concluded that the novel approach presented in this article, that is, to heat treat implants as well as controlled partial coating of them by HA, prior to their insertion to host bone, produce an enhancement of bone growth to metal implants greater than utilization of each method alone. Our findings may be used to further enhance bony in-growth to metal implants in several clinical settings, producing avid implants with superior integration capabilities.
    Journal of Biomedical Materials Research Part A 03/2012; 100(7):1668-72. · 2.63 Impact Factor
  • Article: Near infrared transcranial laser therapy applied at various modes to mice following traumatic brain injury significantly reduces long-term neurological deficits.
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    ABSTRACT: Near-infrared transcranial laser therapy (TLT) has been found to modulate various biological processes including traumatic brain injury (TBI). Following TBI in mice, in this study we assessed the possibility of various near-infrared TLT modes (pulsed versus continuous) in producing a beneficial effect on the long-term neurobehavioral outcome and brain lesions of these mice. TBI was induced by a weight-drop device, and neurobehavioral function was assessed from 1 h to 56 days post-trauma using the Neurological Severity Score (NSS). The extent of recovery is expressed as the difference in NSS (dNSS), the difference between the initial score and that at any other later time point. An 808-nm Ga-Al-As diode laser was employed transcranially 4, 6, or 8 h post-trauma to illuminate the entire cortex of the brain. Mice were divided into several groups of 6-8 mice: one control group that received a sham treatment and experimental groups that received either TLT continuous wave (CW) or pulsed wave (PW) mode transcranially. MRI was taken prior to sacrifice at 56 days post-injury. From 5-28 days post-TBI, the NSS of the laser-treated mice were significantly lower (p<0.05) than those of the non-laser-treated control mice. The percentage of surviving mice that demonstrated full recovery at 56 days post-CHI (NSS=0, as in intact mice) was the highest (63%) in the group that had received TLT in the PW mode at 100 Hz. In addition, magnetic resonance imaging (MRI) analysis demonstrated significantly smaller infarct lesion volumes in laser-treated mice compared to controls. Our data suggest that non-invasive TLT of mice post-TBI provides a significant long-term functional neurological benefit, and that the pulsed laser mode at 100 Hz is the preferred mode for such treatment.
    Journal of neurotrauma 01/2012; 29(2):401-7. · 4.25 Impact Factor
  • Article: [Ulnar entrapment neuropathy].
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    ABSTRACT: Ulnar nerve entrapment is one of the most common entrapment neuropathies in the upper limb. The most frequent location of this syndrome is behind the elbow. The clinical picture is associated with the localization of the entrapment but usually consists of an altered sensation at the fourth and fifth digits and a weakness of the intrinsic muscles of the palm. The most constructive tool in making the diagnosis and in assessing the treatment's efficacy is the physical examination. Treatment alternatives depend on entrapment location. Conservative treatment options such as rest, a change in the work environment and patterns as well as splints are all accepted modalities. A lack of improvement following conservative treatment or a deteriorating nerve function is an indication for surgical intervention. This includes procedures comprised of decompression of the ulnar nerve alone or those which combine its transposition.
    Harefuah 02/2010; 149(2):104-7, 123.
  • Article: Long-term results of proximal femoral osteotomy in Legg-Calvé-Perthes disease.
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    ABSTRACT: Legg-Calvé-Perthes disease is a childhood hip disorder that may result in a deformed and poorly functioning hip. The purpose of this study was to evaluate the correlation between hip deformity at skeletal maturity and degenerative osteoarthritis and to present the long-term results of proximal femoral varus derotational osteotomy in Legg-Calvé-Perthes disease. We analyzed the results of 40 patients (43 hips), who underwent proximal femoral varus derotational osteotomy for Legg-Calvé-Perthes disease in our institution between 1959 and 1983. All available patients underwent a single long-term follow-up examination. Hips were classified with the classification system of Stulberg. Osteoarthritis was evaluated using the Tönnis classification. The long-term outcomes were evaluated after a mean follow-up period of 33 years. When examining the outcome using the Stulberg classification system, there were 8 Stulberg class I hips (19.5%), 15 Stulberg class II hips (36.6%), 8 Stulberg class III hips (19.5%), 9 Stulberg class IV hips (22%), and 1 Stulberg class V hip (2.4%). One patient, who had a bilateral Legg-Calvé-Perthes disease, underwent total hip replacement for osteoarthritis. Seven patients had poor clinical results. Proximal femoral varus derotational osteotomy provides good long-term results for Legg-Calvé-Perthes disease. The Stulberg classification is a good predictor for patient outcome. Level IV, therapeutic study.
    Journal of pediatric orthopedics 01/2009; 28(8):819-24. · 1.23 Impact Factor
  • Article: [Osteochondritis dissecans of the knee].
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    ABSTRACT: Osteochondritis dissecans of the knee is diagnosed at an increasing rate among adolescents and young adults. One of the reasons is due to the increasing number of sports participants among these populations. Although many theories exist, the cause of osteochondritis dissecans is unknown. Early diagnosis is very important. While adult type osteochondritis dissecans is unstable, in most young patients it is stable, and patients with an intact articular surface have a good chance to heal with non-operative treatment and cessation of physical activity. The value of complementary treatment (bed rest, partial weight bearing, bracing aimed at reducing weight bearing of the involved knee) is unknown. Patients with open physes and stable lesions, who failed non-operative treatment, may be treated with local bone drilling, encouraging lesion healing. As the disease progresses, more aggressive measures should to be taken, whilst decreasing success ratios are expected. The healing potential of the lesion may be evaluated by magnetic resonance imaging. Most adult type osteochondritis dissecans patients, as most young patients, with unstable lesions and loose bodies within their knees, are treated with fixation of the lesions and even bone grafting. Many unstable lesions will heal after fixation, but the long-term prognosis is elusive. Chronic loose bodies are very difficult to fix, with less favorable outcomes. Excision of large lesions originating from weight bearing cartilage is not favorable and different rehabilitation measures of local cartilage damage are not encouraging.
    Harefuah 08/2008; 147(7):618-23, 661.
  • Article: Lumbar stenosis and systemic diseases: is there any relevance?
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    ABSTRACT: A retrospective study of spinal stenosis patients admitted to Assaf Harofeh Medical Center Orthopedic Departments. To assess any correlation between systemic disease and spinal stenosis. Lumbar stenosis is a common spinal disease with various etiologies. No findings have been reported correlating spinal stenosis incidence with background diseases, although diabetes mellitus (DM) has been found to play a role in intervertebral disc degeneration and spondylolisthesis. Hospitalization records of patients with spinal stenosis admitted to Assaf Harofeh Medical Center Orthopedic Departments between 1984 and 1993 were checked for background diseases, age, and sex. The data collected were statistically evaluated for any correlation between spinal stenosis and chronic diseases and compared with the data published by the "Israeli Bureau of Statistics" and Israel's largest Health Maintenance Organization's chronic disease survey. Of 537 patients with spinal stenosis 57% (308) were males and (229) 43% females with an average age of 60+/-14 years. Diseases occurring with a high incidence were hypertension (HTN)-23.2% (compared with 7.8% in the general population), DM-13.6% (5.9%), ischemic heart disease (IHD)-11.9%, and hyperlipidemia-4.4%. Patients with spinal stenosis had no significant age and sex distribution difference compared with the general population and no such difference was found for patients suffering from HTN, IHD, or DM. Isolating the effect of DM on HTN and IHD revealed that HTN was a primary disease whereas IHD was secondary to DM with significant statistical validation (P=0.003). To the best of our knowledge this is the first study linking spinal stenosis and DM or HTN. It was found that chronic diseases do not alter the natural age and sex distribution of spinal stenosis. The major question remaining concerns the biologic mechanism linking spinal stenosis and DM or HTN.
    Journal of Spinal Disorders & Techniques 06/2008; 21(4):247-51. · 1.50 Impact Factor
  • Article: [Tennis elbow (lateral epicondylitis)--assessment and treatment].
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    ABSTRACT: Tennis elbow typically presents as pain and localized tenderness at the lateral aspect of the elbow. It is the most common diagnosis related to the elbow. Microtrauma at the vicinity of the Extensor Carpi Radialis Brevis muscle is postulated to be the cause of this clinical entity. Initial treatment should be conservative and is successful in up to 90% of cases. Modalities such as patient education, physiotherapy, use of splints, anti-inflammatory medication, complementary medicine and eventually local injections are all acceptable treatment methods. Surgical treatment of tennis elbow should be used only as a last resort. Both open and arthroscopic methods are acceptable and their results are considered to be excellent.
    Harefuah 05/2008; 147(4):340-3, 373.
  • Article: [Shoulder pain: assessment, diagnosis and treatment of common problems].
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    ABSTRACT: Shoulder pain is a common complaint seen at the primary physician's clinic, and it is the third most common musculoskeletal complaint after back and neck pain. Shoulder pain can have a wide range of etiologies: trauma caused from a sprain or a simple muscle strain to a large tear of one of the shoulder stabilizer muscles. Some shoulder pathologies can cause chronic pain and limitation in shoulder range of motion such as impingement syndrome, adhesive capsulitis, calcified tendonitis, cervical radiculopathy, glenohumeral osteoarthritis, and biceps tendonitis. The physician who attempts to diagnose the cause for his patient's shoulder pain faces a great challenge due to the large number of etiologies that can lead to such a complaint. The physician has a large number of tools at his disposal starting from a thorough history emphasizing the time and character of the shoulder pain, range of motion and the ability to do everyday activities, to a wide range of imaging modalities such as X-ray, ultrasound and magnetic resonance imaging. Most of the causes of shoulder pain are adequately treated non-surgically with treatments such as physiotherapy, antiinflammatory medication and local corticosteroid injections. However, some situations necessitate surgical intervention in order to correct and restore the patient's prior level of shoulder function. The physician's ability to correctly diagnose and recommend appropriate lines of treatment, taking into consideration the patient's problem, age, medical condition and prior level of function is the secret to successful treatment, recovery of the patient's shoulder function and most important, patient satisfaction.
    Harefuah 02/2008; 147(1):71-6, 93.
  • Article: low-level laser therapy applied transcranially to mice following traumatic brain injury significantly reduces long-term neurological deficits.
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    ABSTRACT: Low-level laser therapy (LLLT) has been evaluated in this study as a potential therapy for traumatic brain injury (TBI). LLLT has been found to modulate various biological processes. Following TBI in mice, we assessed the hypothesis that LLLT might have a beneficial effect on their neurobehavioral and histological outcome. TBI was induced by a weight-drop device, and motor function was assessed 1 h post-trauma using a neurological severity score (NSS). Mice were then divided into three groups of eight mice each: one control group that received a sham LLLT procedure and was not irradiated; and two groups that received LLLT at two different doses (10 and 20 mW/cm(2) ) transcranially. An 808-nm Ga-As diode laser was employed transcranially 4 h post-trauma to illuminate the entire cortex of the brain. Motor function was assessed up to 4 weeks, and lesion volume was measured. There were no significant changes in NSS at 24 and 48 h between the laser-treated and non-treated mice. Yet, from 5 days and up to 28 days, the NSS of the laser-treated mice were significantly lower (p < 0.05) than the traumatized control mice that were not treated with the laser. The lesion volume of the laser treated mice was significantly lower (1.4%) than the non-treated group (12.1%). Our data suggest that a non-invasive transcranial application of LLLT given 4 h following TBI provides a significant long-term functional neurological benefit. Further confirmatory trials are warranted.
    Journal of Neurotrauma 04/2007; 24(4):651-6. · 3.65 Impact Factor
  • Article: Low-level laser therapy applied transcranially to rats after induction of stroke significantly reduces long-term neurological deficits.
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    ABSTRACT: Low-level laser therapy (LLLT) modulates various biological processes. In the present study, we assessed the hypothesis that LLLT after induction of stroke may have a beneficial effect on ischemic brain tissue. Two sets of experiments were performed. Stroke was induced in rats by (1) permanent occlusion of the middle cerebral artery through a craniotomy or (2) insertion of a filament. After induction of stroke, a battery of neurological and functional tests (neurological score, adhesive removal) was performed. Four and 24 hours poststroke, a Ga-As diode laser was used transcranially to illuminate the hemisphere contralateral to the stroke at a power density of 7.5 mW/cm2. In both models of stroke, LLLT significantly reduced neurological deficits when applied 24 hours poststroke. Application of the laser at 4 hours poststroke did not affect the neurological outcome of the stroke-induced rats as compared with controls. There was no statistically significant difference in the stroke lesion area between control and laser-irradiated rats. The number of newly formed neuronal cells, assessed by double immunoreactivity to bromodeoxyuridine and tubulin isotype III as well as migrating cells (doublecortin immunoactivity), was significantly elevated in the subventricular zone of the hemisphere ipsilateral to the induction of stroke when treated by LLLT. Our data suggest that a noninvasive intervention of LLLT issued 24 hours after acute stroke may provide a significant functional benefit with an underlying mechanism possibly being induction of neurogenesis.
    Stroke 11/2006; 37(10):2620-4. · 5.73 Impact Factor
  • Article: Effects of power densities, continuous and pulse frequencies, and number of sessions of low-level laser therapy on intact rat brain.
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    ABSTRACT: The aim of the present study was to investigate the possible short- and long-term adverse neurological effects of low-level laser therapy (LLLT) given at different power densities, frequencies, and modalities on the intact rat brain. LLLT has been shown to modulate biological processes depending on power density, wavelength, and frequency. To date, few well-controlled safety studies on LLLT are available. One hundred and eighteen rats were used in the study. Diode laser (808 nm, wavelength) was used to deliver power densities of 7.5, 75, and 750 mW/cm2 transcranially to the brain cortex of mature rats, in either continuous wave (CW) or pulse (Pu) modes. Multiple doses of 7.5 mW/cm2 were also applied. Standard neurological examination of the rats was performed during the follow-up periods after laser irradiation. Histology was performed at light and electron microscopy levels. Both the scores from standard neurological tests and the histopathological examination indicated that there was no long-term difference between laser-treated and control groups up to 70 days post-treatment. The only rats showing an adverse neurological effect were those in the 750 mW/cm2 (about 100-fold optimal dose), CW mode group. In Pu mode, there was much less heating, and no tissue damage was noted. Long-term safety tests lasting 30 and 70 days at optimal 10x and 100x doses, as well as at multiple doses at the same power densities, indicate that the tested laser energy doses are safe under this treatment regime. Neurological deficits and histopathological damage to 750 mW/cm2 CW laser irradiation are attributed to thermal damage and not due to tissue-photon interactions.
    Photomedicine and Laser Surgery 09/2006; 24(4):458-66. · 1.25 Impact Factor
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    Article: Deep vein thrombosis prevention in joint arthroplasties: continuous enhanced circulation therapy vs low molecular weight heparin.
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    ABSTRACT: Deep vein thrombosis prevention efficacy using a new, miniature, mobile, battery-operated pneumatic system (continuous enhanced circulation therapy [CECT] system) combined with low-dose aspirin was compared to enoxaparin. One hundred twenty-one patients who underwent total hip or knee arthroplasty were prospectively randomized into 2 groups. The study group was treated by the CECT system starting immediately after the induction of anesthesia. Postoperatively, a daily 100-mg aspirin tablet was added. The control group received 40 mg of enoxaparin per day. Bilateral venography was performed at the fifth to eight postoperative day. In the CECT group, as compared to the enoxaparin group, there was a significantly lower overall rate of DVT and proximal DVT. Safety profiles were similar in both groups. The combination of the CECT device with low-dose aspirin is more effective than enoxaparin in preventing deep-vein thrombosis after lower limb arthroplasties.
    The Journal of Arthroplasty 03/2006; 21(2):206-14. · 2.38 Impact Factor
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    Article: Transcranial application of low-energy laser irradiation improves neurological deficits in rats following acute stroke.
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    ABSTRACT: Low-level laser therapy (LLLT) has been shown to have beneficial effects on ischemic skeletal and heart muscles tissues. The aim of the present study was to approve the effectiveness of LLLT treatment at different locations on the brain in acute stroked rats. Stroke was induced in 169 rats that were divided into four groups: control non-laser and three laser-treated groups where laser was employed ipsilateral, contralateral, and both to the side of the induced stroke. Rats were tested for neurological function. In all three laser-treated groups, a marked and significant improvement in neurological deficits was evident at 14, 21, and 28 days post stroke relative to the non-treated group. These observations suggest that LLLT applied at different locations in the skull and in a rather delayed-phase post stroke effectively improves neurological function after acute stroke in rats.
    Lasers in Surgery and Medicine 02/2006; 38(1):70-3. · 2.75 Impact Factor
  • Article: [Replantation and revascularization in acute upper limb amputation--the Sheba Medical Center experience].
    Amir Oron, Batia Yaffe
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    ABSTRACT: Replantation and revascularization in acute upper-limb amputations are well-accepted surgical techniques in hand surgery. All medical staff members treating patients in emergency settings should be familiar with the indications, timetable, setup and transportation of patients rendered suitable for such surgery. While replantation surgery is not considered a simple surgical procedure by any means, viability rates approach ninety percent. The amputated part should be wrapped with gauze soaked in saline, placed in a sterile plastic bag and then put in an ice-filled container. The patient should be transferred to a medical center with a team dedicated to performing replantation procedures, following notification in advance. Time from the initial insult to the initiation of treatment should be minimized. Combined efforts employed by the primary caregivers and the microsurgical team will lead to optimization of patient treatment and improve the final outcome. During the years 1991-2007 a total of 383 upper limb replantation or revascularization procedures were performed at the Sheba Medical Center and are presented in this article.
    Harefuah 147(8-9):668-71, 752.

Institutions

  • 2012
    • Kaplan Medical Center
      Yavne, Central District, Israel
    • Tel Aviv University
      • Department of Zoology
      Tel Aviv, Tel Aviv, Israel
  • 2006–2010
    • Assaf Harofeh Medical Center
      Rishon LeẔiyyon, Central District, Israel