Biomedical subjects

N C Yaru

Publications and source records attributed to N C Yaru.

5 recordsLinked to original sources

PubMed1987

Fracture of the tibia complicated by acute compartment syndrome.

A consecutive series of 32 patients with tibia fractures complicated by compartment syndrome was treated with fasciotomy. One group was also treated with closed reduction of the fracture and cast immobilization and compared with a comparable group treated with internal fixation without case immobilization after fasciotomy. All other patients were treated with fasciotomy and reduction followed with either external skeletal fixation, pins and plaster, or skeletal traction. Care of the open fasciotomy incisions, observation of the neurovascular status of the limb, and rehabilitation of the extremity were facilitated by internal fixation operations without subsequent external cast immobilization. The anatomic and functional results in this group were better than those treated with fasciotomy and cast immobilization. All fractures were united by 20 weeks. Complications in both groups were similar, although one deep infection, which was resolved with appropriate treatment, occurred in the group treated with internal fixation. Six open tibia fractures were treated with external skeletal fixation after fasciotomy; the results were less satisfactory, but the initial injuries were also more severe in this group. Patients with closed tibial fractures complicated by compartment syndromes should be treated expeditiously with fasciotomy, followed by stable internal fixation.

Acute Disease↗

PubMed1984

Vibratory sensory testing in acute peripheral nerve compression.

Vibratory thresholds were continually measured with a variable-amplitude vibrometer during periods of controlled median nerve compression in 12 human volunteers. Tissue fluid pressure in the carpal canal was maintained at 50 mm Hg, a level which caused a complete loss of nerve function in all subjects by 45 minutes. In all subjects vibratory thresholds proved to be the earliest test indicating a decrease in nerve function. Semmes-Weinstein pressure testing and 256 cycles/sec vibratory sensibility correlated well with measurements of vibratory thresholds and with the electrodiagnostic testing. Static and moving two-point discrimination did not become abnormal until late in the clinical testing. The vibrometer has significant potential as a clinical and research instrument in nerve compression syndromes. This study supports the use of vibratory stimuli as a noninvasive diagnostic test; it is currently undergoing evaluation in a number of clinical studies.

Adult↗

PubMed1984

Ankle and knee position as a factor modifying intracompartmental pressure in the human leg.

The objective of this study was to examine the effect of position of the knee and ankle on intracompartmental pressures in the leg. Slit catheters were introduced bilaterally into all four muscle compartments of the lower extremities of six healthy volunteers. Intracompartmental pressures were monitored with the catheters while the ankle joint was passively held in full dorsiflexion, full plantar flexion, or neutral with the knee flexed 90 or 10 degrees or fully extended. Statistical analysis revealed that intracompartmental pressure increased significantly in all four compartments when the ankle was passively dorsiflexed. Pressure in the superficial posterior and lateral compartments was dependent on knee position and in the deep posterior and anterior compartments it was independent of knee position. In addition, pressure in the deep posterior compartment decreased significantly when the ankle was placed in full plantar flexion, and that finding was independent of knee position. Anterior compartment pressure was not significantly elevated by full passive plantar flexion of the ankle.

Adult↗

PubMed1983

Tissue pressure threshold for peripheral nerve viability.

To investigate the pressure threshold for peripheral nerve dysfunction in compression syndromes (carpal tunnel and compartment syndromes), carpal canal pressure was elevated to 40, 50, 60, and 70 mm Hg in normal volunteers. Motor and sensory latencies and amplitudes of the median nerve were evaluated before compression, after 30-240 minutes of compression, and during the postcompression recovery phase. Although some functional loss occurred at 40 mm Hg, motor and sensory responses were completely blocked at a threshold tissue fluid pressure of 50 mm Hg, measured by the wick catheter. In one subject in whom diastolic blood pressure was significantly higher than in other subjects, the threshold pressure was raised slightly. The Semmes-Weinstein monofilament test and the 256-cycle vibratory test were more sensitive than two-point discrimination tests for evaluating peripheral nerve function in this compression model. These results indicate that between 40 mm Hg and 50 mm Hg there exists a critical pressure threshold at which peripheral nerve is acutely jeopardized. Compartment decompression may not be indicated when interstitial pressures are below this level.

Action Potentials↗

PubMedDate not supplied

The effect of tibial attachment site on graft impingement in an anterior cruciate ligament reconstruction.

Anterior cruciate ligament reconstructions were performed in 14 cadaveric knee specimens using a 6-mm wide polypropylene graft. The graft was passed through a femoral tunnel at the attachment site of the anterior medial bundle of the anterior cruciate ligament. Seven tibial positions were evaluated as to the change in attachment site distance with passive range of motion and impingement on the intercondylar notch as the knee was passively ranged from 0 degree to 90 degrees of flexion. Impingement was also evaluated while the knee was extended by pulling through the quadriceps tendon. The tibial placement site affects the change in attachment site distance with passive range of motion and impingement on the intercondylar notch. Grafts passed through drill holes anterior and lateral to the insertion of the anterior fibers of the anterior cruciate ligament consistently produced impingement on the anterior outlet of the intercondylar notch. Knee extension with quadriceps tendon pull produced graft impingement in a greater arc of flexion than passive extension. Based on this study, optimum placement of the tibial hole should be at the insertion of the anterior medial fibers of the anterior cruciate ligament. Impingement recognized during surgery can be alleviated with notchplasty. With passive extension there should be a 3-mm clearance between the anterior portion of the intercondylar notch and the ligament graft to prevent the graft from impinging when the knee is actively extended.

Anterior Cruciate Ligament↗