Acetabular blood flow during Bernese periacetabular osteotomy: an intraoperative study using laser Doppler flowmetry.

BACKGROUND: The blood flow to the acetabular fragment is of some concern in juxtaarticular pelvic osteotomies used for the treatment of hip dysplasia. No direct measurements have determined the effect of the Bernese periacetabular osteotomy (PAO) on acetabular perfusion. METHODS: Acetabular perfusion was measured by means of laser Doppler flowmetry in 10 patients undergoing a PAO for symptomatic acetabular dysplasia. During the surgical procedure, the intraosseous high energy laser Doppler reliably depicts dynamic changes of small vessel blood flow. Measurements were performed after defined surgical steps to obtain sequential information on the blood perfusion of the acetabular fragment. RESULTS: After complete separation of the acetabular fragment, nine out of 10 patients had pulsatile signals, but the blood flow (BF) significantly decreased by 77%. Corrective positioning of the fragment induced no further drop of the BF signal but a loss of pulsatility in six patients. After a recovery period of about 30 min following preliminary fixation of the fragment, reestablishment of the pulsatile signal and an increase of the BF signal was seen. At termination of the surgical procedure, five out of eight patients, who could be followed throughout the whole procedure, showed a clear pulsatile signal in the supraacetabular area. Bleeding of the supraacetabular cancellous surface could be observed in all acetabula. CONCLUSION: Despite careful preservation of soft tissues during the surgical procedure, a significant reduction of the blood flow in the supraacetabular region has been observed. Nevertheless, a pulsatile signal in more than 60% of the fragments after fragment correction and an increasing signal during the recovery period showed ongoing blood perfusion indicating reversible changes in the measured supraacetabular area. All osteotomies healed within eight weeks without showing signs of necrosis during a minimum follow up of 1 year.     

Utility of radioisotopic filtration markers in chronic renal insufficiency: simultaneous comparison of 125I-iothalamate, 169Yb-DTPA, 99mTc-DTPA, and inulin. The Modification of Diet in Renal Disease Study

Assessment of glomerular filtration rate (GFR) with inulin is cumbersome and time-consuming. Radioisotopic filtration markers have been studied as filtration markers because they can be used without continuous intravenous (IV) infusion and because analysis is relatively simple. Although the clearances of 99mTc-diethylenetriamine-pentaacetic acid (DTPA), 169Yb-DTPA, and 125I-iothalamate have each been compared with inulin, rarely has the comparability of radioisotopic filtration markers been directly evaluated in the same subject. To this purpose, we determined the renal clearance of inulin administered by continuous infusion and the above radioisotopic filtration markers administered as bolus injections, simultaneously in four subjects with normal renal function and 16 subjects with renal insufficiency. Subjects were studied twice in order to assess within-study and between-study variability. Unlabeled iothalamate was infused during the second half of each study to assess its effect on clearances. We found that renal clearance of 125I-iothalamate and 169Yb-DTPA significantly exceeded clearance of inulin in patients with renal insufficiency, but only by several mL.min-1.1.73m-2. Overestimation of inulin clearance by radioisotopic filtration markers was found in all normal subjects. No differences between markers were found in the coefficient of variation of clearances either between periods on a given study day (within-day variability) or between the two study days (between-day variability). The true test variability between days did not correlate with within-test variability. We conclude that the renal clearance of 99mTc-DTPA, 169Yb-DTPA, or 125I-iothalamate administered as a single IV or subcutaneous injection can be used to accurately measure GFR in subjects with renal insufficiency; use of the single injection technique may overestimate GFR in normal subjects.     

Dorsal and ventral dopaminergic innervation of the spinal cord: Functional implications

Several studies have demonstrated that a descending dopaminergic pathway innervates the dorsal and the intermediate gray matter of the spinal cord and have suggested that this pathway is involved in pain modulation and in the control of autonomie functions. Other studies have also demonstrated the presence of dopamine (DA) and DA metabolites as well as of DA receptors in the ventral cord. There is also evidence for the implication of DA in the control of motor functions at the spinal level. The occurrence of a dopaminergic innervation in the ventral horn has been, however, disputed until recently. But recent work has demonstrated that the motoneural cell groups in the ventral horn (lamina IX) are a target for descending dopaminergic fibers. In addition, the possibility that DA is a mediator of primary afferent fibers has also been postulated. Finally, the occurrence of dopaminergic cell bodies has been suggested in the spinal cord. This indicates that DA is probably implicated in a complex manner in spinal functions. In the present paper the possible involvement of DA in sensory and in motor functions at spinal level will be discussed in view of neurochemical observations made in polyarthritic rats, in which pain-related behavior and reduction of locomotor activity associated with a marked decrease in mobility, are observed.     

Remifentanil for use during conscious sedation in outpatient oral surgery.

PURPOSE: Remifentanil is a new, short-acting opioid that is similar pharmacodynamically to currently available opioids but differs in its pharmacokinetics. In the present study, we compared the use of remifentanil with the use of meperidine during intravenous conscious sedation for third molar surgery. PATIENTS AND METHODS: Forty patients who were scheduled for the removal of impacted third molars were randomly assigned to undergo 1 of 2 intravenous conscious sedation techniques. For both groups, 50:50 nitrous oxide oxygen were administered via nasal hood, and midazolam was titrated to Verril's sign. Twenty patients each then received either remifentanil 0.05 microgram/kg/min or meperidine 50 mg. Both patients and surgeons were blinded to the narcotic that was used. Blood pressure, heart rate, and oxygen saturation were determined before sedation and every 5 minutes during surgery. Recovery was measured using serial Trieger tests every 5 minutes after surgery. Patient and surgeon satisfaction of the quality of sedation was measured with a visual analog scale. RESULTS: Peak heart rate (91 beats/min for remifentanil vs 107 beats/min for meperidine, P <.01) and peak systolic blood pressure (131 mm Hg for remifentanil vs. 142 mm Hg for meperidine, P <.05) were significantly lower for the remifentanil group. Although there was a trend toward increased surgeon satisfaction with remifentanil (86 of 100 with remifentanil vs. 73 of 100 with meperidine), it was not found to be statistically significant. Likewise, other physiologic parameters were not found to be statistically significant. CONCLUSIONS: The lower peak heart rate and systolic blood pressure levels indicate that remifentanil may allow for less fluctuation in cardiovascular parameters. This could prove beneficial in patients with cardiovascular compromise.     

Human papillomavirus genotype distribution in low-grade cervical lesions: comparison by geographic region and with cervical cancer.

Low-grade squamous intraepithelial lesions (LSIL) associated with certain human papillomavirus (HPV) genotypes may preferentially progress to cervical cancer. HPV genotyping may thus have the potential to improve the effectiveness of screening programs and to reduce overtreatment. LSIL cases (n = 8,308) from 55 published studies were included in a meta-analysis. HPV genotype distribution was assessed by geographic region and in comparison with published data on cervical squamous cell carcinoma (SCC). HPV detection in LSIL was 80% in North America but less than 70% in other regions, most likely reflecting regional differences in LSIL diagnosis. Among 5,910 HPV-positive LSILs, HPV16 was the most common genotype (26.3%) followed by HPV31 (11.5%), HPV51 (10.6%), and HPV53 (10.2%). HPV-positive LSILs from Africa were 2-fold less likely to be infected with HPV16 than those in Europe, and HPV-positive LSILs from North America were more likely to be infected with HPV18 than those from Europe or South/Central America. Interpretation for rarer genotypes was hampered by variation in HPV testing methodology. SCC/LSIL prevalence ratios indicated that HPV16 was 2-fold and HPV18 was 1.5-fold more common in SCC than in HPV-positive LSIL, thus appearing more likely to progress than other high-risk genotypes (SCC/LSIL prevalence ratios between 0.05 and 0.85). HPV53 and HPV66 showed SCC/LSIL ratios of 0.02 and 0.01, respectively. HPV genotype distribution in LSIL differs from that in cervical cancer, highlighting the importance of HPV genotype in the risk of progression from LSIL to malignancy. Some regional differences in the relative importance of HPV genotypes in LSIL were noted.