RESUMO
PURPOSE: This study was designed to quantify tensile forces within the intra-articular long head of the bicep tendon (LHBT) under conditions of passive limb positioning and physiologic load, which simulate contraction of the LHBT. MATERIALS AND METHODS: A force probe was inserted into the intra-articular LHBT, just distal to its supra-glenoid origin, in six fresh-frozen cadaveric specimens. Initially, specimens were manually manipulated through 30 glenohumeral joint positions, combining humeral rotation and elbow/forearm position. In the second phase, a 55 N tensile load was applied through the LHBT in 18 limb positions. Intra-tendinous tension was recorded in all positions under both conditions. RESULTS: External humeral rotation significantly increased tension with glenohumeral forward flexion (P<0.0001). Conversely, internal humeral rotation significantly increased tension with glenohumeral abduction and extension (P<0.0001). A position of glenohumeral extension and internal rotation, with the elbow extended and forearm pronated, produced the highest tension in the intra-articular LHBT (P<0.0001). Under applied load conditions, observed LHTB tension was not statistically different in any glenohumeral position (P=0.1468, power = 88%). The greater tuberosity was noted to impinge on the force probe in forward flexion and internal rotation in two specimens. CONCLUSIONS: Variable tensile forces are seen in the intra-articular LHBT as a function of both limb position and simulated biceps contraction. Our findings provide a thorough data set that may be used to help substantiate or refute current or future hypotheses regarding LHBT function, pathology, and clinical tests. CLINICAL RELEVANCE: Identifying positions of glenohumeral motion, which affect LHBT tension will provide an anatomic basis for clinical tests proposed to be for diagnosing LHBT lesions, including superior labral anterior and posterior tears.
RESUMO
STUDY DESIGN: A case report of cauda equina syndrome (CES) in an 11-month-old infant, following sacrococcygeal teratoma tumor resection and coccyx excision leading to a spinal epidural hematoma (SEH). OBJECTIVE: To illustrate a rare case of CES and SEH in an infant, and discuss the need for sealing access to the spinal canal after sacrococcygeal surgical resection and reconstruction. SUMMARY OF BACKGROUND DATA: To the authors' knowledge, this is the youngest patient reported to develop a SEH and CES, and the only patient reported in the literature to develop a SEH after coccyx excision. METHODS: Seventeen days after undergoing sacrococcygeal tumor resection and coccyx excision, the patient presented to the emergency room with a large distended bladder, loss of rectal tone, and significant weakness in the lower extremities. Magnetic resonance imaging of the thoracic and lumbar spine showed a large lesion in the dorsal epidural space extending from T12 to the tip of the communicating with the prior operative site by means of the previous coccyx resection. The infant was emergently brought to the operating room for decompression. RESULTS: The patient was discharged 6 days later with diminished neurologic function, but demonstrated significant improvement over the next 18 months and currently remains disease free and neurologically normal at age 7. CONCLUSION: This case demonstrates the need for future examination of sacrococcygeal surgical resection and subsequent reconstruction of excised structures to decrease the risk of communication with the epidural space.
