Biomedical subjects

Mark W Anderson

Publications and source records attributed to Mark W Anderson.

10 recordsLinked to original sources

PubMed2006

Imaging of upper extremity stress fractures in the athlete.

Although it is much less common than injuries in the lower extremities, an upper extremity stress injury can have a significant impact on an athlete. If an accurate and timely diagnosis is to be made, the clinician must have a high index of suspicion of a stress fracture in any athlete who is involved in a throwing, weightlifting, or upper extremity weight-bearing sport and presents with chronic pain in the upper extremity. Imaging should play an integral role in the work-up of these patients; if initial radiographs are unrevealing, further cross-sectional imaging should be strongly considered. Although a three-phase bone scan is highly sensitive in this regard, MRI has become the study of choice at most centers.

Arm Injuries↗

PubMed2005

Development of HIV fusion inhibitors.

In the past 25 years, the worldwide AIDS epidemic has grown such that roughly 38 million people were estimated to be living with the disease worldwide at the end of 2003. The introduction of antiretroviral-based therapies, beginning in 1987, has enabled many to live with HIV as a chronic, rather than terminal, disease. However, the emergence and spread of drug-resistant strains highlights the continued need for new therapies with novel modes of action. In 2003, the FDA and EMEA approved enfuvirtide (Fuzeon), a 36 amino acid peptide derived from the natural gp41 HR2 sequence, as the first HIV fusion inhibitor. T-1249, a 39 amino acid fusion inhibitor, is active against viruses that develop resistance to enfuvirtide. The development of FIs and the processes to manufacture enfuvirtide and T-1249 on an unprecedented scale for peptide therapeutics are presented. Synthetic routes based on a combination of solid phase peptide synthesis and solution phase fragment condensation as well as the analytical controls necessary to insure a robust process are discussed.

Drug Design↗

PubMed2004

Lumbar discography: an update.

Discogenic pain most commonly affects the low back, buttocks, and hips and is thought to be a byproduct of internal disk degeneration. It is postulated that progressive annular breakdown and tearing results in biomechanical and/or biochemical stimulation of the pain fibers that reside in the outer one third of the annulus. Although multiple imaging modalities, most notably MRI, can show morphologic abnormalities of the spine, discography remains the only test that provides physiologic information regarding what role a given intervertebral disk plays in a patient's symptom complex. The controversy surrounding discography is here to stay until more definitive, well-designed studies are performed. In the meantime, there are certain things that can help the discographer maximize the accuracy of the test: 1. Always try to inject one "normal" disk as a "control level." 2. Be alert for factors that are associated with an increased false-positive rate (abnormal non-anatomic pain maps, a history of chronic pain of spinal or nonspinal origin, abnormal psychometric testing, and prior surgery at the injected disk level). In these cases, special attention should be directed to both the patient's verbal and nonverbal cues during disk injection. 3. Do not give any audible clues as to what level is being injected or when the injection is starting or finishing. In this regard, we find it very helpful to have one of our personnel talk with the patient during this portion of the procedure while closely observing the patient for any nonverbal cues regarding their pain response. This distraction is preferable to a silent room where the patient is intensely focused on what is going on with the injections. We also find that music playing during the procedure helps to relax and often distract the patient as well. 4. If the results are equivocal at a level (i.e., you are unable to determine whether or not the patient's pain response was truly concordant), go on to inject another disk level and then come back to reinject more contrast into the disk in question. As radiologists, we tend to focus on the technical aspects of a procedure and the anatomic/morphologic information it provides. However, it cannot be emphasized enough that when performing lumbar discography, the assessment of the patient's pain response during the injection is the most important component of the procedure, and requires not only technical skills, but an understanding of how best to avoid some of the pitfalls that can lead to inaccurate results.

Contrast Media↗

PubMed2004

Fluoroscopically guided low-volume peritendinous corticosteroid injection for Achilles tendinopathy. A safety study.

BACKGROUND: The safety and efficacy of corticosteroid injection for the treatment of Achilles tendinopathy is not known, with some reports indicating the hazard of tendon rupture and others extolling the efficacy of such injections. This study was undertaken to assess the safety of fluoroscopically guided corticosteroid injections into the peritendinous space for the treatment of Achilles tendinopathy. METHODS: A series of patients was treated with fluoroscopically guided corticosteroid injections into the space surrounding the Achilles tendon. Major and minor complications were recorded, as were the number of repeat injections, the duration of symptomatic relief attained with the injection, and a subjective rating of symptoms related to the Achilles tendon. RESULTS: Of eighty-three patients who had been treated, seventy-eight were available for follow-up and forty-three met our requirement for a minimum two-year follow-up (average duration of follow-up, 37.4 months). No major complications and one minor complication occurred in the forty-three patients. Seventeen (40%) of the patients reported improvement after the procedure, twenty-three (53%) thought that their condition was unchanged, and three (7%) felt that their condition was worse than it had been prior to the injection. CONCLUSIONS: This retrospective cohort study establishes the safety of low-volume injections of corticosteroids for the treatment of Achilles tendinopathy when the needle is carefully inserted into the peritendinous space under direct fluoroscopic visualization.

Achilles Tendon↗

PubMed2004

Use of ultrasound in determining treatment for avulsion of the flexor digitorum profundus (rugger jersey finger): a case report.

Avulsion of the flexor digitorum profundus (rugger jersey finger) commonly occurs in athletes as a result of forced extension of a flexed distal interphalangeal joint. Ultrasound can be a useful tool in defining the anatomy of a tendon avulsion when no fracture is present. In subacute situations, the degree of tendon retraction has important implications for the treatment of these common injuries. Use of ultrasound for closed flexor tendon injuries has not been covered enough in the hand surgery literature. We report on the use of ultrasound as a diagnostic tool in evaluating and treating subacute avulsion injuries to the flexor digitorum profundus.

Adult↗

PubMed2003

Chondral injury after arthroscopic meniscal repair using bioabsorbable Mitek Rapidloc meniscal fixation.

Arthroscopic meniscal repair is a commonly performed procedure in clinical practice. With improvements in bioabsorbable implants, all-inside techniques have increased in popularity. The Mitek RapidLoc meniscal fixation implant may be used to fix reparable meniscal tears arthroscopically without requiring an additional incision. We report 2 potential complications associated with this implant: chondral injury causing femoral grooving and recurrent meniscal tear 4 months after initial surgery.

Absorbable Implants↗

PubMed2002

MR imaging of the meniscus.

It should be the goal of any radiologist who interprets MRI examinations of the knee to be able not only to recognize normal meniscal anatomy and accurately diagnose meniscal pathology, but also to develop a better grasp of the surgical implications of the imaging findings. By thinking more like an arthroscopist, one can provide a more clinically relevant report, and by doing so, add value to the work-up of a patient who presents with a potential meniscal tear.

Cartilage Diseases↗

PubMed2002

The knee: bone marrow abnormalities.

MRI is clearly the imaging modality of choice for detecting and exploring joint, osseous, and soft tissue injuries in the lower extremity and throughout the musculoskeletal system. Its ability to detect and differentiate the various forms of marrow pathology is unrivaled, and as such it should be obtained early in the work-up of a patient with a suspected marrow abnormality. Additionally, the radiologist must be familiar with the MRI appearances of normal marrow and the most common types of marrow pathology if its diagnostic power is to be fully realized.

Arthritis↗

PubMedDate not supplied

Magnetic resonance imaging of the elbow: update on current techniques and indications.

The utility of magnetic resonance imaging of the elbow has noticeably improved over the past decade. Advances in equipment and refinement of pulse sequences has allowed for superior visualization of many pathologic processes involving the elbow joint and its surrounding structures. At this time, magnetic resonance imaging is most valuable in detecting occult fractures, osteochondritis dissecans, collateral ligament tears, nonossified intra-articular loose bodies, and soft tissue masses. It may also aid in the diagnosis of tendinous injuries, compression neuropathies, and synovial disorders. This article serves as an educational update for hand surgeons and illustrates the features of normal anatomy and specific disorders of the elbow.

Arthrography↗

PubMedDate not supplied

Intra-articular migration of a sutureless arthroscopic rotator cuff fixation device.

Rotator cuff tears are a common orthopaedic condition. Recent new advances in arthroscopic equipment and devices has allowed many rotator cuff tears to be repaired arthroscopically. Some of these newer devices allow sutureless repair of rotator cuff tears. We report a case of failure in intra-articular migration of such a fixation device. Displacement of the device was noted 4 months after surgery on magnetic resonance arthography. The device was removed arthroscopically with no long-term sequelae. Nevertheless, it is important to recognize that these devices have the potential for intra-articular migration. Due diligence is required in placing these devices. As with all arthroscopic procedures, there appears to be a learning curve associated with the use of sutureless rotator cuff repair fixation devices.

Aged↗