Predictors of blood transfusion in patients undergoing elective surgery for degenerative conditions of the spine.

BACKGROUND: The requirement of blood in the surgery of degenerative conditions of lumbar spine is around 10 %. Preoperative autologous blood donation is an effective method that is used in surgeries with an important blood loss. This is an expensive method because of the great number of predonated blood units not used in the postoperative period (around 70 % in our practice). OBJECTIVE: To know the risk factors associated with transfusion in the postoperative period in patients who undergo surgeries of degenerative conditions of the lumbar spine. METHODS: We designed a retrospective study of 142 cases of patients operated for degenerative conditions of the lumbar spine (not including simple disk hernia or adult degenerative scoliosis). RESULTS: Female sex, age >60 years, preoperative ASA score 3 and preoperative hemoglobin ≤136 g/L are the risk factors related to the need of blood transfusion in the postoperative period. After application of a statistical study, female sex and preoperative ASA score 3 were the most important variables to explain transfusional risk. A woman with ASA score 3 has a 61 % foretold probability to be transfused in the postoperative period, while a man with ASA < 3, only 1.1 %. For this reason, application of this method to patients with these risk factors is more cost-effective. CONCLUSIONS: Females, ASA 3, preoperative hemoglobin ≤136 g/L and age older than 60 years increase the risk to be transfused in the postoperative period for degenerative conditions of the spine.

Regenerated cartilage produced by autogenous periosteal grafts: a histologic and mechanical study in rabbits under the influence of continuous passive motion.

PURPOSE: To evaluate the repaired tissues formed in full-thickness cartilage defects in a rabbit model implanted with autogenous periosteal grafts under the influence of continuous passive motion (CPM) establishing a correlation between histology, histomorphometry, and mechanical behavior. METHODS: Autogenous periosteal grafts were used to resurface full-thickness defects produced in the trochlear groove in the right knees of 60 New Zealand rabbits. Four groups were formed according to the time to death and postoperative mobilization: group A--active intermittent motion, euthanized at 8 weeks; group B--CPM, euthanized at 8 weeks; group C--active intermittent motion, euthanized at 36 weeks; and group D, CPM, euthanized at 36 weeks. Repaired tissues were evaluated grossly, histologically, and mechanically, as well as by histomorphometry. RESULTS: The repair tissue was hyaline-like cartilage in 68.1% of the specimens in group A, 71.4% in group B, 0% in group C, and 20% in group D. The mean thickness of the regenerated tissue was 1.20 mm in group A, 1.23 mm in group B, 0.20 mm in group C, and 0.25 in group D. Elastic stiffness at 8 weeks was lower than that of the control cartilage and increased significantly at 36 weeks because of degenerative changes. Postoperative motion showed no influence on the results. Repaired tissue developed severe degenerative changes in time, and deterioration of the mechanical properties was observed without any protective effect of the CPM. CONCLUSIONS: Full-thickness cartilage defects treated with autologous periosteal grafts were repaired with hyaline-like cartilage tissue. Regenerated tissue showed viscoelastic behavior similar to normal cartilage 8 weeks after surgery. CPM did not improve histologic or mechanical results. Repaired tissue did not last over time. CLINICAL RELEVANCE: Free periosteal grafts should not be used clinically in the treatment of full-thickness cartilage defects because even though regenerated tissue seems initially to be hyaline-like cartilage, it is not capable of maintaining its histologic and mechanical properties over a long period of time.

Effectiveness of using blended learning strategies for teaching and learning human anatomy.

OBJECTIVES: This study aimed to implement innovative teaching methods--blended learning strategies--that include the use of new information technologies in the teaching of human anatomy and to analyse both the impact of these strategies on academic performance, and the degree of user satisfaction. METHODS: The study was carried out among students in Year 1 of the biology degree curriculum (human biology profile) at Pompeu Fabra University, Barcelona. Two groups of students were tested on knowledge of the anatomy of the locomotor system and results compared between groups. Blended learning strategies were employed in 1 group (BL group, n = 69); the other (TT group; n = 65) received traditional teaching aided by complementary material that could be accessed on the Internet. Both groups were evaluated using the same types of examination. RESULTS: The average marks presented statistically significant differences (BL 6.3 versus TT 5.0; P < 0.0001). The percentage pass rate for the subject in the first call was higher in the BL group (87.9% versus 71.4%; P = 0.02), reflecting a lower incidence of students who failed to sit the examination (BL 4.3% versus TT 13.8%; P = 0.05). There were no differences regarding overall satisfaction with the teaching received. CONCLUSIONS: Blended learning was more effective than traditional teaching for teaching human anatomy.