Minimum Alveolar Concentration of Volatile Anesthetics in Rats during Postnatal Maturation

Background: Although neonatal rats have become widely used as experimental laboratory animals, minimum alveolar concentration (MAC) values of volatile anesthetics in rats during postnatal maturation remain unknown.

Methods: We determined MAC values of volatile anesthetics in spontaneously breathing neonatal (2-, 9-, and 30-day-old) and adult Wistar rats exposed to increasing (in 0.1-0.2% steps) concentrations of halothane, isoflurane, or sevoflurane (n = 12-20 in each group), using the tail-clamp technique. MAC and its 95% confidence intervals were calculated using logistic regression and corrected for body temperature (37[degrees]C).

Results: In adult rats, inspired MAC values corrected at 37[degrees]C were as follows: halothane, 0.88% (confidence interval, 0.82-0.93%); isoflurane, 1.12% (1.07-1.18%); and sevoflurane, 1.97% (1.84-2.10%). In 30-day-old rats, the values were as follows: halothane, 1.14% (1.07-1.20%); isoflurane, 1.67% (1.58-1.76%); and sevoflurane, 2.95% (2.75-3.15%). In 9-day-old rats, inspired MAC values were as follows: halothane, 1.68% (1.58-1.78%); isoflurane, 2.34% (2.21-2.47%); and sevoflurane, 3.74% (3.64-3.86%). In 2-day-old rats, inspired MAC values were as follows: halothane, 1.54% (1.44-1.64%); isoflurane, 1.86% (1.72-2.01%); and sevoflurane, 3.28% (3.09-3.47%).     

Reverse total shoulder arthroplasty: a review of results according to etiology

BACKGROUND: Reverse total shoulder arthroplasty provides a surgical alternative to standard total shoulder arthroplasty for the treatment of selected complex shoulder problems. The purpose of the present study was to evaluate the effects of etiology on the results of reverse total shoulder arthroplasty. METHODS: Between May 1995 and June 2003, 240 consecutive reverse total shoulder arthroplasties were performed in 232 patients with an average age of 72.7 years. Patients were grouped according to etiology, and the clinical and radiographic outcomes for each group were measured and compared. RESULTS: One hundred and eighty-six patients with 191 retained reverse total shoulder arthroplasty prostheses were followed for an average of 39.9 months. Overall, the average Constant score improved from 23 points before surgery to 60 points at the time of follow-up and 173 of the 186 patients were satisfied or very satisfied with the result. Although substantial clinical and functional improvement was observed in all etiology groups, patients with primary rotator cuff tear arthropathy, primary osteoarthritis with a rotator cuff tear, and a massive rotator cuff tear had better outcomes, on average, than patients who had posttraumatic arthritis and those managed with revision arthroplasty. Dislocation (fifteen cases) and infection (eight cases) were the most common complications among the 199 shoulders that were followed for two years or were revised prior to the minimum two-year follow-up. Patients who received the reverse prosthesis at the time of a revision arthroplasty had a higher complication rate than did those who received the reverse prosthesis at the time of a primary arthroplasty. CONCLUSIONS: The reverse total shoulder arthroplasty prosthesis can produce good results when used for the treatment of a number of other complex shoulder problems in addition to cuff tear arthropathy. Patients with posttraumatic arthritis and those undergoing revision arthroplasty may have less improvement and higher complication rates in comparison with patients with other etiologies. The advanced age of the patients in the present series and the relatively short duration of follow-up suggest that the prosthesis should continue to be used judiciously.     

Tramadol added to 1.5% mepivacaine for axillary brachial plexus block improves postoperative analgesia dose-dependently

Adjuncts to local anesthetics for peripheral plexus blockade may enhance the quality and duration of anesthesia and postoperative analgesia. The analgesic, tramadol, has a unique mechanism of action that suggests efficacy as such an adjunct. It displays a central analgesic and peripheral local anesthetic effect. We designed a prospective, randomized, controlled and double-blind clinical trial to assess the effect of tramadol added to brachial plexus anesthesia. One-hundred patients scheduled for carpal tunnel release surgery under brachial plexus anesthesia were randomized into four groups. All patients received 1.5% mepivacaine 40 mL plus a study solution containing either isotonic sodium chloride (Group P, n = 17), tramadol 40 mg (Group T(40), n = 22), tramadol 100 mg (Group T(100), n = 20) or tramadol 200 mg (Group T(200), n = 20). We evaluated the time of onset of anesthesia, duration of sensory and motor blockade, duration and quality of postoperative analgesia, and occurrence of adverse effects. Onset and duration of sensory and motor blocks were not different among groups. The number of patients requesting analgesia in the postoperative period was significantly less in the 3 tramadol groups compared with the placebo group (P = 0.02); this was also noted with the placebo and T(40) groups compared with the T(200) group. No statistical significance was demonstrated between the placebo and the T(40) group or the T(100) group and the T(200) group. Furthermore, there was a significant trend effect among groups applying the Cochran-Armitage tendency test (P = 0.003), suggesting a dose-dependent decrease for additional postoperative analgesia requirements when tramadol was added. Side effects did not differ among groups, although they were more frequently recorded in the T groups. Our study suggests that tramadol added to 1.5% mepivacaine for brachial plexus block enhances in a dose-dependent manner the duration of analgesia with acceptable side effects. However, the safety of tramadol has to be investigated before allowing its use in clinical practice. IMPLICATIONS: Tramadol's unique mechanism of action suggests efficacy as a local anesthetic adjunct for peripheral plexus blockade. Our study demonstrates that tramadol, added to mepivacaine for brachial plexus anesthesia, extends the duration and improves the quality of postoperative analgesia in a dose dependent fashion with acceptable side effects.     

Sagittal alignment and kinematics at instrumented and adjacent levels after total disc replacement in the cervical spine

Background

The purpose of the study was to report radiological outcomes after total disc replacement (TDR) in the cervical spine through a 24 months follow-up (FU) prospective study with a special focus on sagittal alignment and kinematics at instrumented and adjacent levels.

Materials and methods

Thirty-two patients, who sustained one-level TDR with a ball-and-socket arthroplasty (Discocerv^™ implant, Scient’x/Alphatec Spine, USA) were consecutively included in the study. Clinical (visual analogical scale and neck disability index) and radiological parameters were measured preoperatively and postoperatively at 3/6 months, 1-year and 2-year FU. Sagittal alignment, ranges of motion (ROM) and center of rotations (CORs) were analyzed using specific motion analysis software (Spineview^™, Paris, France). Patients CORs were compared with those of a control group of 39 normal and asymptomatic subjects.

Results

Both local and C3–C7 lordosis significantly increased postoperatively (+8° and +13° at 2 years, respectively). At instrumented level ROM in flexion–extension (FE) was measured to 10.2° preoperatively versus 7.5° at 1 year and 6.1° at 2 years. There were no differences in ROM at adjacent levels between pre and postoperative assessments. When compared with control group and preoperative measurements, we noted postoperative cranial shift of the COR at instrumented level for patients group. In contrast, there was no difference in CORs location at adjacent levels.

Conclusion

Through this prospective study, we observed that cervical lordosis consistently increased after TDR. In addition, although ball-and-socket arthroplasty did not fully restore native segmental kinematics with significant reduction of motion in FE and consistent cranial shift of the COR, no significant changes in terms of ROM and CORs were observed at adjacent levels.     

Manual therapy followed by specific active exercises versus a placebo followed by specific active exercises on the improvement of functional disability in patients with chronic non specific low back pain: a randomized controlled trial

ABSTRACT: BACKGROUND: Recent clinical recommendations still propose active exercises (AE) for CNSLBP. However, acceptance of exercises by patients may be limited by pain-related manifestations. Current evidences suggest that manual therapy (MT) induces an immediate analgesic effect through neurophysiologic mechanisms at peripheral, spinal and cortical levels. The aim of this pilot study was first, to assess whether MT has an immediate analgesic effect, and second, to compare the lasting effect on functional disability of MT plus AE to sham therapy (ST) plus AE. METHODS: Forty-two CNSLBP patients without co-morbidities, randomly distributed into 2 treatment groups, received either spinal manipulation/mobilization (first intervention) plus AE (MT group; n = 22), or detuned ultrasound (first intervention) plus AE (ST group; n = 20). Eight therapeutic sessions were delivered over 4 to 8 weeks. Immediate analgesic effect was obtained by measuring pain intensity (Visual Analogue Scale) before and immediately after the first intervention of each therapeutic session. Pain intensity, disability (Oswestry Disability Index), fear-avoidance beliefs (Fear-Avoidance Beliefs Questionnaire), erector spinae and abdominal muscles endurance (Sorensen and Shirado tests) were assessed before treatment, after the 8th therapeutic session, and at 3- and 6-month follow-ups. RESULTS: Thirty-seven subjects completed the study. MT intervention induced a better immediate analgesic effect that was independent from the therapeutic session (VAS mean difference between interventions: -0.8; 95% CI: -1.2 to [MINUS SIGN]0.3). Independently from time after treatment, MT + AE induced lower disability (ODI mean group difference: -7.1; 95% CI: -12.8 to [MINUS SIGN]1.5) and a trend to lower pain (VAS mean group difference: -1.2; 95% CI: -2.4 to [MINUS SIGN]0.30). Six months after treatment, Shirado test was better for the MT group (Shirado mean group difference: -61.6; 95% CI: -117.5 to [MINUS SIGN]5.7). Insufficient evidence for group differences was found in remaining outcomes. CONCLUSIONS: This study confirmed the immediate analgesic effect of MT over ST. Followed by specific active exercises, it reduces significantly functional disability and tends to induce a larger decrease in pain intensity, compared to a control group. These results confirm the clinical relevance of MT as an appropriate treatment for CNSLBP. Its neurophysiologic mechanisms at cortical level should be investigated more thoroughly.Trial registrationTrial registration number: NCT01496144.     

Concurrent validity of SMTEC footswitches system for the measurement of temporal gait parameters

The GAITRite system is a validated portable gait analysis system that allows simple objective gait measurements. The limited length of the active area of the GAITRite system may be a limitation in obtaining reliable measures of stride-to-stride variability. In contrast, the SMTEC footswitches system provides a continuous measurement of temporal step parameters for a long distance and a long period (around 24 h). The aim of the study was to examine the concurrent validity of the SMTEC footswitches system with the GAITRite system for the measurement of temporal steps parameters. Step, stride, swing and stance time were simultaneously recorded using SMTEC and GAITRite systems while walking at normal, slow and fast self-selected walking speed among 13 healthy young adults. The level of agreement between both systems was high as for the stride time with intra-class correlation coefficients (ICC) between 0.95 and 0.99 (P<0.001) and repeatability coefficients (RC) between 1.1% and 1.5% of mean values, whereas the lowest level of agreement was shown at fast self-selected walking speed and for stance time (ICC=0.52 with P<0.001 and RC=4.9%). Furthermore, the measurement of individual footstep data was excellent with an agreement ranging between -0.04 and 0.04 s (Pitman's test of difference in variance: r=-0.009, P=0.772). The present results suggest that the SMTEC footswitches system provides a valid and reliable measurement of temporal gait parameters in healthy young adults.     

Synthesis, radiolabeling and baboon SPECT imaging of 2beta-carbomethoxy-3beta-(3'-[(123)I]iodophenyl)tropane ([(123)I]YP256) as a serotonin transporter radiotracer

To develop a potential SPECT probe to evaluate the integrity of the serotoninergic system (5-HTT) whose dysfunction is linked to several disease conditions such as Parkinson's disease, Alzheimer's disease and depression, we report the synthesis, radiolabeling and in vivo baboon imaging of 2beta-carbomethoxy-3beta-(3'-[(123)I]iodophenyl) tropane (YP256, 6). The radiolabeling was performed by iododestannylation using sodium [(123)I]iodide and peracetic acid. Although the ligand displayed high selectivity for 5-HTT over dopamine transporter in vitro, SPECT imaging in baboons did not reveal selective 5-HTT accumulation in brain in vivo.     

The proximal biceps as a pain generator and results of tenotomy

Many palliative interventions have been proposed for patients in whom rotator cuff repair is not feasible as a result of advanced fatty infiltration, definitive loss of tendons, and proximal humeral migration. The long head of the biceps tendon has been proposed as a source of pain in patients with rotator cuff tears. This article presents a review of current concepts on the rationale for arthroscopic biceps tenotomy or tenodesis, and evaluates the objective, subjective, and radiographic results of these palliative procedures. On the basis of different studies, it seems that isolated arthroscopic biceps tenotomy or tenodesis is a valuable option for the treatment of rotator cuff tears in selected patients. Although it does not improve shoulder strength, tenotomy or tenodesis reduces pain and improves the functional range of motion with a high degree of patient satisfaction. However, the progressive radiographic changes that occur with long standing rotator cuff tears are not altered.     

Temporary fibrin glue occlusion of the main pancreatic duct in the prevention of intra-abdominal complications after pancreatic resection: prospective randomized trial

OBJECTIVE: To determine whether temporary occlusion of the main pancreatic duct with human fibrin glue decreases the incidence of intra-abdominal complications after pancreatoduodenectomy (PD) or distal pancreatectomy (DP). SUMMARY BACKGROUND DATA: To the authors' knowledge, there are no randomized studies comparing outcomes after pancreatic resection with or without main pancreatic duct occlusion by injection of fibrin glue. Of three nonrandomized studies, two reported no fistulas after intracanal injection and ductal occlusion with fibrin glue after PD with immediate pancreatodigestive anastomosis, while another study reported no protective effect of glue injection. METHODS: This prospective, randomized, single-blinded, multicenter study, conducted between January 1995 and January 1999, included 182 consecutive patients undergoing PD followed by immediate pancreatic anastomosis or DP, whether for benign or malignant tumor or for chronic pancreatitis. One hundred two underwent pancreatic resection followed by ductal occlusion with fibrin glue (made slowly resorbable by the addition of aprotinin); 80 underwent resection without ductal occlusion. The main end point was the number of patients with one or more of the following intra-abdominal complications: pancreatic or other digestive tract fistula, intra-abdominal collections (infected or not), acute pancreatitis, or intra-abdominal or digestive tract hemorrhage. Severity factors included postoperative mortality, repeat operations, and length of hospital stay. RESULTS: The two groups were similar in pre- and intraoperative characteristics except that there were significantly more patients in the ductal occlusion group who were receiving octreotide, who had reinforcement of their anastomosis by fibrin glue, and who had fibrotic pancreatic stumps. However, the rate of patients with one or more intra-abdominal complications, and notably with pancreatic fistula, did not differ significantly between the two groups. There was still no significant difference found after statistical adjustment for these patient characteristic discrepancies, confirming the inefficacy of fibrin glue. The rate of intra-abdominal complications was significantly higher in the presence of a normal, nonfibrotic pancreatic stump and main pancreatic duct diameter less than 3 mm, whereas reinforcement of the anastomosis with fibrin glue or use of octreotide did not influence outcome. In multivariate analysis, however, normal pancreatic parenchyma was the only independent risk factor for intra-abdominal complications. No significant differences were found in the severity of complications between the two groups. CONCLUSIONS: Ductal occlusion by intracanal injection of fibrin glue decreases neither the rate nor the severity of intra-abdominal complications after pancreatic resection.