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Biomedical subjects

G Chaimsky

Publications and source records attributed to G Chaimsky.

9 recordsLinked to original sources
PubMed2002

The anatomy of tibial eminence fractures: arthroscopic observations following failed closed reduction.

BACKGROUND: Failed manipulative reduction of avulsion fractures of the tibial insertion of the anterior cruciate ligament has been attributed to interposition of soft tissues, particularly the anterior horn of the medial meniscus. The objectives of the present report were (1) to show that the failure to reduce Meyers and McKeever type-III tibial eminence fractures was not due to interposition of soft tissues and (2) to discuss the relevance of the finding that the anterior third of the lateral meniscus was attached to the avulsed anterior cruciate ligament insertion site in all patients studied. METHODS: Twelve patients who had had a failed manipulative reduction of a type-III tibial eminence fracture underwent arthroscopic reduction and fixation of the avulsed fragment. RESULTS: A number of consistent findings were noted. The avulsed intercondylar eminence was displaced superiorly into the intercondylar notch. Attached to this fragment was not only the anterior cruciate ligament, but also, in all cases, the anterior horn of the lateral meniscus. The anterior third of the lateral meniscus had been torn from its tibial attachment and displaced together with the osseous fragment into the intercondylar notch. No interposition of bone or soft tissue was observed. Reduction of the osseous fragment was facilitated by traction on, or sutures passed around, the anterior horn of the lateral meniscus. Standard fixation methods were utilized. CONCLUSIONS: The concept that avulsion fractures of the tibial insertion of the anterior cruciate ligament cannot be reduced by manipulation because of soft-tissue interposition was not supported by the findings of the present study. The attachment of the anterior horn of the lateral meniscus to the avulsed tibial insertion of the anterior cruciate ligament may not be an irrelevant incidental finding. The observation that the displaced osseous fragment was attached simultaneously to the anterior cruciate ligament and to the anterior horn of the lateral meniscus, both pulling in different directions, may explain why type-III tibial eminence fractures are irreducible by manipulation.

Adolescent↗
PubMed2001

Collapsing the tibial bone tunnel in hamstring autograft reconstruction of the anterior cruciate ligament.

The use of double staples is an accepted method for fixation of hamstring anterior cruciate ligament (ACL) grafts at the distal tibial site. In the last year, we have modified the 2-staple technique that we have been using for distal tibial fixation of our double loop hamstring ACL autografts. Previously, we had impacted the graft with 2 toothed staples onto the cortex distal to the opening of the tibial tunnel. The modification we report here involves driving the proximal staple into the tibial tunnel roof, thus collapsing the tunnel onto the tendon during fixation. The distal staple is introduced in the usual manner. Clinical follow-up including subjective and objective KT-1000 arthrometry has indicated no difference in the early results compared with the former staple technique. Radiologic follow-up showed tunnel obliteration and filling in the area of the proximal staple, suggesting early graft incorporation in callus. While early results are encouraging, long-term follow-up and pullout studies will be reported. It would appear that collapsing the bony tunnel by the proximal staple may be a simple method of providing fracture callus to increase the stiffness of the tibial graft fixation, with no major or minor complications. Animal experiments are being carried out to objectively define the mechanical advantage of the graft incorporation by callus.

Animals↗
PubMed1992

Use of dual-energy X-ray absorptiometry (DEXA) to follow mineral content changes in small ceramic implants in rats.

Dual energy X-ray absorptiometry (DEXA) imaging was used to quantify bone ingrowth into hydroxyapatite (HA) ceramic implants in rats. HA cylinders implanted in the proximal tibiae were followed for 13 wk. The increase in alkaline phosphatase (ALP) activity within the implants preceded the increase in mineral content as measured non-invasively by the DEXA technique. This was consistent with the timing of ALP activity in respect of mineralization as they occur during fracture healing. The results show that DEXA imaging is useful in measuring bone ingrowth into small ceramic HA implants in vivo, despite the high mineral content background of the implant scaffold.

Absorptiometry, Photon↗
PubMed1991

Pyogenic vertebral osteomyelitis with paralysis. Prognosis and treatment.

In the interval between 1983 and 1988, 14 patients were treated for pyogenic spondylitis complicated by neurologic compromise. There were nine males and five females aged 39-80 years. The average time between onset of symptoms and diagnosis was 2.8 months. Predisposing factors were diabetes mellitus in four patients and urinary tract infections in five patients. The infection was blood borne in all 14 patients. In two patients, the infection was superimposed on a recent vertebral fracture. The cervical spine was involved in one patient; the thoracic spine in seven; and the lumbar spine in six patients. Six patients presented with a Frankel B paralysis, six with a Frankel C paralysis, and two with grade D paralysis. The neurologic symptoms lasted between one day and six weeks before surgery. Twelve patients had anterolateral decompression. Two of the 12 patients had a second stage posterior stabilization. Two patients were deemed inoperable. All surviving patients were managed by parenteral antibiotics for three to six weeks followed by enteral route for a total of three to six months. All 12 operated patients had a significant neurologic improvement (one grade or more on the Frankel scale) with solid interbody fusion.

Adult↗
PubMed1990

A rabbit model for evaluation of spinal anesthesia: chronic cannulation of the subarachnoid space.

A rabbit model for evaluation of spinal anesthesia is presented. Chronic cannulation of the subarachnoid space was performed in 44 rabbits using the translumbar approach. An autopsy was performed 24 h after the operation on four of the animals. Intrathecal injections of methylene blue did not reveal any leakage from the spinal space. X-ray examination performed on the second and 30th days after the implantation indicated free spread of the injected solution in the subarachnoid space without any obstruction. Repeated injections of four identical doses of bupivacaine at 3-day intervals showed reproducible pharmacologic effects. Administration of different doses of the anesthetic produced a clear dose-response relationship. The relative activity of the anesthetic agents was found to be identical to that previously obtained in humans. No significant complications after the implantation have been recorded. We suggest the current model as an additional appropriate tool for the investigation of spinal anesthesia.

Anesthesia, Spinal↗