Biomedical subjects

David P Magit

Publications and source records attributed to David P Magit.

3 recordsLinked to original sources

PubMed2006

Healos/recombinant human growth and differentiation factor-5 induces posterolateral lumbar fusion in a New Zealand white rabbit model.

STUDY DESIGN: Posterolateral lumbar spine fusions in New Zealand white rabbits. OBJECTIVE: To evaluate the efficacy of recombinant human growth and differentiation factor-5 (rhGDF-5) lyophilized to a Healos carrier (cross-linked type I collagen with hydroxyapatite coating; DePuy Spine, Inc., Raynham, MA) in inducing fusion. SUMMARY OF BACKGROUND DATA: Bone graft substitutes have become an area of considerable interest. rhGDF-5 is one such product. Limited lumbar preclinical studies have been performed with this product. METHODS: Single-level, intertransverse process fusions were performed in 67 rabbits using iliac crest autograft (n = 13), Healos alone (n = 13), or 0.5, 1.0, or 1.5 mg/cc rhGDF-5 lyophilized to Healos (n = 13 per group). At 8 weeks, the rabbits were euthanized. Fusion masses were assessed. RESULTS: There were 2 animals (3%) lost to complication. Manual palpation revealed fusion rates for autograft of 38% (5/13), Healos alone of 0% (0/13), and each of the Healos/rhGDF-5 groups of 100% (13/13). Histologic analyses were 95% sensitive and 95% specific for confirming fusion. Histologic differences were found among the treatment groups. CONCLUSIONS: In this rabbit fusion model, Healos/rhGDF-5 induced fusion in 100% of the rabbits studied. This rate was significantly higher than the fusion rate induced by autograft (38%). Overall, these results support continued research of Healos/rhGDF-5 as a potential bone graft alternative.

Animals↗

PubMed2006

Arthroscopic fixation of bursal-sided rotator cuff tears.

Subacromial decompression and debridement of partial-thickness bursal-sided rotator cuff tears are often reported with a high rate of unsatisfactory outcomes. We describe an arthroscopic procedure to repair partial-thickness bursal-sided rotator cuff tears without converting to a full-thickness tear in patients with a normal articular-sided rotator cuff and an A0B2 or A0B3 pattern of tear (minimum thickness of 25% to 75%). The articular side of the rotator cuff experiences greater tension than the bursal side of the cuff. As such, by leaving the articular footprint intact, we accomplish 3 goals: the intact articular fibers act as an internal splint to protect the bursal-sided repair, a wide and anatomic footprint is recreated, and we are able to minimize any length-tension mismatch because the tissue is not excessively lateralized with repair. After bursectomy and acromioplasty, the frayed edges of the bursal flap are gently debrided and the tuberosity is excoriated to bleeding bone. One or two bioabsorbable anchors are placed, and both sutures are placed through the full thickness of the rotator cuff (one anterior and one posterior) by use of a percutaneous suture lasso in this manner: (1) the lasso is passed through the full thickness of the cuff, and the nitinol wire is shuttled out of a single cannula along with the more medial of the suture limbs; (2) the nitinol wire is then pulled back out of the percutaneous portal along with the suture limb, with the suture being passed through the full thickness of the cuff; and (3) the procedure is repeated for the posterior limb of the suture after a lasso is again passed through the full thickness of the rotator cuff in a more posterior position. This subset of patients is treated with an aggressive rehabilitation protocol because the intact articular rotator cuff fibers act as an internal splint to protect the bursal repair.

Absorbable Implants↗

PubMed2006

Partial-thickness rotator cuff tears.

Partial-thickness rotator cuff tears are not a single entity; rather, they represent a spectrum of disease states. Although often asymptomatic, they can be significantly disabling. Overhead throwing athletes with partial-thickness rotator cuff tears differ with respect to etiology, goals, and treatment from older, nonathlete patients with degenerative tears. Pathogenesis of degenerative partial-thickness tears is multifactorial, with evidence of intrinsic and extrinsic factors playing key roles. Diagnosis of partial-thickness rotator cuff tears should be based on the patient's symptoms together with magnetic resonance imaging studies. Conservative treatment is successful in most patients. Surgery generally is considered for patients with symptoms of sufficient duration and intensity. The role of acromioplasty has not been clearly delineated, but it should be considered when there is evidence of extrinsic causation for the partial-thickness rotator cuff tear.

Acromion↗