Biomedical subjects

G Lemmon

Publications and source records attributed to G Lemmon.

3 recordsLinked to original sources

PubMed2001

Cervical spine instability: clearance using dynamic fluoroscopy.

Cle aring the cervical spine in a multiply injured trauma patient is a dilemma because clinical examination for ligamentous instability cannot be performed, and the standard cervical spine series can miss isolated ligamentous injury. Static flexion/extension views are unsafe, as the obtunded patient has no protective reflexes and cannot complain of pain during the exam. This results in a need for prolonged spinal immobilization and its attendant complications. Dynamic fluoroscopy may be useful in the detection of otherwise occult injuries.We performed a prospective study of a cervical spine clearance algorithm incorporating dynamic fluoroscopy with flexion/extension views. Inpatient records over a 3-year period were reviewed. Patient demographic data, results of cervical spine films and fluoroscopic exams, interventions based on positive results, and missed injuries were recorded.One hundred ten patients with normal spine plain films underwent dynamic fluoroscopy with flexion and extension views of the cervical spine. The average Glasgow Coma Score was 9.2 and the average revised Trauma Score was 9.5. Nine patients had evidence of cervical instability on exam. Six of these were deemed stable by the orthopedic or neurosurgical spine consultants, and these patients had their hard collars removed. One patient with positive findings had cervical immobilization with hard collar continued, a second had halo placement, and a third underwent spinal fusion for atlanto-occipital disassociation. No patients undergoing dynamic fluoroscopy were subsequently found to have missed cervical spine injury.With our protocol, 3 patients had significant cervical instability that would have been missed without dynamic fluoroscopy. Given the significant medical and legal ramifications of missed cervical spine injury and the benefits of early removal of cervical collars, more widespread use of dynamic fluoroscopy of the cervical spine is warranted.

Journal Article↗

PubMed1999

The role of glutamine in skeletal muscle ischemia/reperfusion injury in the rat hind limb model.

OBJECTIVES: Ischemia/reperfusion injury is a commonly occurring event with severe pathologic consequences. Reperfusion initiates both the local and systematic damage in part through rapid oxygen generation. The glutathione system is a major mechanism of reducing this oxidative stress. If this system can be maintained or augmented during this stress then less damage may occur. Glutamine provides the source of glutamate to this system and has been shown to preserve total glutathione levels after injury/ischemia to both hepatic and gut models. To test this effect, we looked at glutamine and its role in ischemia/reperfusion injury in a rat hind limb model. METHODS: Fifty male HSD/Holtzman rats weighing 350-400 g were randomized to receive glutamine (3% sol) or normal saline via intraperitoneal injections. The groups were then subjected to 2 hours of ischemia to their hind limbs using the Tourni-Cot method. Animals were then randomized to reperfusion groups of 30 minutes, 2 hours, and 4 hours. Muscle tissue assays were performed for lipid peroxidation (LPO), total glutathione (GSH), and myeloperoxidase (MPO). Peripheral blood was analyzed for creatinephosphokinase levels (CPK). RESULTS: Animals that received glutamine showed a general trend of less lipid peroxidation products than the normal saline groups. In animals that received glutamine and underwent 2 hours of ischemia and reperfusion times of 0 minutes, 30 minutes, and 2 hours, there were significantly less percent changes in lipid peroxidation products from controls (4.6% vs 48.2%, P <0.05), (18.9% vs 123%, P <0.05), (12.6% vs 115%, P <0.05). A general trend upward was noted in CPK levels in both groups. In animals receiving 2 hours of ischemia and 30 minutes of reperfusion, there was a significantly greater level of creatinephosphokinase (CPK) calculated as percent change from control in the normal saline group as compared with the glutamine group (209.2% vs 92.7%). Myeloperoxidase assay of muscle tissue revealed a progressive increase as the reperfusion times grew. In animals receiving 2 hours of ischemia and 30 minutes of reperfusion, the normal saline group had a significantly larger percent increase from controls than the group that received glutamine (1126.4% vs 108%, P <0.05). Also, in those animals receiving 4 hours of reperfusion, the normal saline group had a significantly higher percent increase in MPO content than the glutamine group (6245% vs 108%, P <0.05). Total glutathione levels decreased rapidly as reperfusion occurred in both the normal saline and glutamine groups. No significant difference between the groups was noted. CONCLUSIONS: Total glutathione levels during reperfusion were not significantly different in the groups receiving glutamine versus normal saline. Glutamine may provide an initial protective effect on reperfusion injury after moderate reperfusion times in the hind limb model as defined by CPK and LPO levels. Glutamine may blunt neutrophil recruitment after longer reperfusion times (4 hours) in the ischemic hind limb. Total glutathione levels decreased significantly after moderate levels of ischemia (2 hours) and reperfusion (30 minutes, 2 hours).

Animals↗

PubMed1994

Clinical experience with the Greenfield filter in 193 patients and description of a new technique for operative insertion.

Transvenous inferior vena cava (IVC) interruption using the Greenfield filter was performed upon 193 patients from January 1982 to December 1988. Placement of a filter in the IVC was indicated for prophylaxis (23.8 percent), contraindication to anticoagulation (22.8 percent), pulmonary embolism despite anticoagulation (18.7 percent), complications of anticoagulation (26.9 percent) and free-floating thrombus (7.8 percent). Filters were placed in an infrarenal location in 92 percent of the patients. The remaining 8 percent of patients had placement of a suprarenal filter for specific indications, without complication. Most (97.4 percent) of the patients had filters placed through internal jugular or femoral vein cutdown. Five patients required filter placement through a retroperitoneal approach to the right common iliac vein and IVC junction. This new technique of filter insertion is described. The operative morbidity rate was 4.7 percent, with an additional 8.8 percent having postoperative thrombotic complications. The 30 day operative mortality rate (6.7 percent) was related to preexisting associated disease. Nonfatal, late, recurrent pulmonary embolism occurred in 2.6 percent of the patients despite filter placement. Caval patency remains at 97.9 percent in long term follow-up evaluation. The Greenfield filter is an effective and safe adjunct in the treatment of venous thromboembolic disease and a satisfactory prophylactic measure in specific high-risk patients.

Adolescent↗