Trochanteric osteotomy and fixation during total hip arthroplasty

Once used routinely, trochanteric osteotomy in total hip arthroplasty now is usually limited to difficult primary and revision cases. There are three types: the standard trochanteric osteotomy and its variations, the trochanteric slide, and the extended trochanteric osteotomy. Each has unique indications, fixation techniques, and complications. Primary total hip arthroplasty procedures requiring the enhanced exposure provided by trochanteric osteotomy may be needed in patients with hip ankylosis or fusion, protrusio acetabuli, proximal femoral deformities, developmental dysplasia, or abductor muscle laxity. Trochanteric osteotomies in revision arthroplasties, primarily the extended trochanteric osteotomy, facilitate the removal of well-fixed femoral components, provide direct access to the diaphysis for distal fixation, and enhance acetabular exposure.     

The Intubating Dose of Succinylcholine: The Effect of Decreasing Doses on Recovery Time

Background: The usually cited "intubation dose" of succinylcholine is 1.0 mg/kg. In the majority of patients, this dose will produce apnea of sufficient duration that significant hemoglobin desaturation may occur before neuromuscular recovery takes place in those whose ventilation is not assisted. This study was undertaken to examine the extent to which reducing this dose would decrease the duration of action of succinylcholine.

Methods: During stable desflurane/oxygen/opioid anesthesia and after adequate twitch stabilization, neuromuscular function was recorded with an acceleromyographic monitor. Supramaximal stimuli were delivered at 0.10 Hz. Patients received 0.40, 0.60, or 1.0 mg/kg succinylcholine, and twitch height was monitored for at least 20 min thereafter.

Results: The onset times to maximal effect were 105 +/- 23 s, 81 +/- 19 s, and 71 +/- 22 s, respectively. The lowest dose (0.40 mg/kg) did not reliably produce 100% twitch depression. The times to 90% twitch recovery at the adductor pollicis in the three groups were 6.6 +/- 1.5 min, 7.6 +/- 1.6 min, and 9.3 +/- 1.2 min, respectively.     

Effects of perioperative administration of a selective cyclooxygenase 2 inhibitor on pain management and recovery of function after knee replacement: a randomized controlled trial

Context  Controlling postoperative pain after knee replacement while reducing opiod-induced adverse effects and improving outcomes remains an important challenge. Objective  To assess the effect of combined preoperative and postoperative administration of a selective inhibitor of cyclooxygenase 2 on opioid consumption and outcomes after total knee arthroplasty (TKA). Design, Setting, and Patients  Randomized, placebo-controlled, double-blind trial conducted June 2001 through September 2002, enrolling 70 patients aged 40 to 77 years and undergoing TKA at a university hospital in the United States. Interventions  Patients were randomly assigned to receive 50 mg of oral rofecoxib at 24 hours and at 1 to 2 hours before TKA, 50 mg daily for 5 days postoperatively, and 25 mg daily for another 8 days, or matching placebo at the same times. Main Outcome Measures  Postoperative outcomes including postsurgical analgesic consumption and pain scores achieved, nausea and vomiting, joint range of motion, sleep disturbance, patient satisfaction with analgesia, and hematologic and coagulation parameters. Results  Total epidural analgesic consumption and in-hospital opioid consumption were less in the group receiving rofecoxib compared with the group receiving placebo (P<.05). Median pain score (visual analog scale [VAS], 0-10) achieved for the knee was lower in the rofecoxib group compared with the placebo group during hospital stay (2.2 [interquartile range {IQR}, 1.4-3.2] vs 3.5 [IQR, 2.7-4.3], P<.001) and 1 week after discharge (2.6 [IQR, 1.4-3.5] vs 3.7 [IQR, 2.9-4.7], P = .03). There was less postoperative vomiting in the rofecoxib group (6%) compared with the placebo group (26%) (P = .047), as well as a decrease in sleep disturbance compared with the placebo group on the night of surgery (P = .006) and on the first (P = .047) and second (P<.001) days postoperatively. Knee flexion was increased in the rofecoxib group compared with the placebo group at discharge (active flexion: mean [SD], 84.2° [11.1°] vs 73.2° [13.6°], P = .03; passive flexion: 90.5° [6.8°] vs 81.8° [13.4°], P = .05) and at 1 month postoperatively (109.3° [8.5°] vs 100.8° [11.8°], P = .01), with shorter time in physical therapy to achieve effective joint range of motion. The rofecoxib group was more satisfied with analgesia and anesthesia at discharge compared with the placebo group (median satisfaction score, 4.3 [IQR, 3.0-4.7] vs 3.3 [IQR, 2.3-4.3], respectively; P = .03), and the differences persisted at 2-week and at 1-month follow-up. There was no intergroup difference in surgical blood loss (P>.05 for both intraoperative and postoperative blood loss). Conclusion  Perioperative use of an inhibitor of cyclooxygenase 2 is an effective component of multimodal analgesia that reduces opioid consumption, pain, vomiting, and sleep disturbance, with improved knee range of motion after TKA.      

Effects of attentional load on auditory scene analysis

The effects of attention on the neural processes underlying auditory scene analysis were investigated through the manipulation of auditory task load. Participants were asked to focus their attention on tuned and mistuned stimuli presented to one ear and to ignore similar stimuli presented to the other ear. For both tuned and mistuned sounds, long (standard) and shorter (deviant) duration stimuli were presented in both ears. Auditory task load was manipulated by varying task instructions. In the easier condition, participants were asked to press a button for deviant sounds (target) at the attended location, irrespective of tuning. In the harder condition, participants were further asked to identify whether the targets were tuned or mistuned. Participants were faster in detecting targets defined by duration only than by both duration and tuning. At the unattended location, deviant stimuli generated a mismatch negativity wave at frontocentral sites whose amplitude decreased with increasing task demand. In comparison, standard mistuned stimuli generated an object-related negativity at central sites whose amplitude was not affected by task difficulty. These results show that the processing of sound sequences is differentially affected by attentional load than is the processing of sounds that occur simultaneously (i.e., sequential vs. simultaneous grouping processes), and that they each recruit distinct neural networks.     

The niacin skin flush abnormality in schizophrenia: a quantitative dose-response study

Niacin dilates cutaneous blood vessels, resulting in a pronounced skin flush in most people. The flush response to niacin is attenuated in schizophrenia, but the quantification and physiological mechanism of this abnormality have not been described in detail. It is not clear whether the mechanism involves changes in the pharmacological sensitivity to niacin, or whether there is a reduced ability of the vasculature to dilate adequately in subjects with schizophrenia. We address this question in the present study by characterizing the dose-response relationship between topically applied alpha-methylnicotinate (AMN) and cutaneous blood flow changes, which were quantified by laser Doppler flowmetry. The dose-response curve was shifted to the right in subjects with schizophrenia. The EC(50) value of AMN was significantly increased in the schizophrenia group (mean: 1.66 mM; 95% confidence interval: 1.04-2.65 mM) as compared to the control group (mean: 0.38 mM; 95% confidence interval: 0.263-0.547 mM). The blood flow responses to higher AMN doses were lower in the schizophrenics; however, there was no statistically significant difference in the extrapolated maximal blood flow response value (F(max)) between the two groups. The results suggest that the skin flush abnormality in schizophrenia primarily reflects reduced pharmacological sensitivity to niacin rather than an inadequate cutaneous vasodilatory response to the stimulus. Since vasodilatation in response to niacin requires the release of prostaglandins, the data from this study suggest that schizophrenia is associated with abnormalities in enzymes, receptors, or signal transduction mechanisms that affect the synthesis, release, or response to vasodilatory prostaglandins.     

Correlates of adjudicative competence among psychiatrically impaired juveniles

This study examines the competence-related abilities of 120 psychiatrically hospitalized male juveniles age 10 to 17 years, using the MacArthur Competence Assessment Tool-Criminal Adjudication (MacCAT-CA), the Brief Psychiatric Rating Scale-Anchored (BPRS-A), the Massachusetts Youth Screening Instrument (MAYSI), the Kaufman Brief Intelligence Test (K-BIT), and discharge diagnoses derived from file review. The findings indicate significant age-related differences across adolescence with a relatively strong performance for most of the youths on the competence measure. While intellectual and psychiatric factors were found to contribute substantially to deficits in legal decisional ability, they were modulated by age and the developmental factors associated with it. These findings, replete with caveats concerning both the dimensional structure of competence as measured by the MacCAT-CA and the interplay with the mental status and developmental factors affecting it, underscore the multifarious nature of legal decisional capacity in youths of varying ages. The relevance of these findings to the structuring of restoration services and the application of legal theory to the competence standard in juvenile court are discussed.     

Emerging surgical and radiotherapeutic techniques for treating epilepsy

PURPOSE OF REVIEW: Recent advances in epilepsy surgery have developed a resurgence of interest in the use of surgical techniques for the treatment of intractable epilepsy. RECENT FINDINGS: More invasive procedures such as hemispherectomy and multiple subpial transection have become more popular. Disconnective techniques such as multiple subpial transection have provided a surgical option for patients whose epileptogenic zone resides in the eloquent cortex. Alternatively, new minimally invasive neurostimulation therapies have been introduced to preserve maximal cerebral tissue. Radiosurgery has been recently utilized in the treatment of epilepsy with preliminary promising results. SUMMARY: In this analysis, the authors will attempt to review the more recent surgical approaches and their indications for the treatment of medically intractable epilepsy. For patients with the epileptogenic zone in the noneloquent cortex, seizure focus resection remains the most reasonable approach to therapy.     

Time-lapse analysis of ethanol's effects on axon growth in vitro

The cortical abnormalities found in animal models of fetal alcohol syndrome (FAS) suggest a disruption of axon growth. After emerging from the cell body, axons exhibit saltatory growth, cycling between periods of extension and periods of retraction. The timing of neuronal process outgrowth an the balance between extension and retraction together determine the net rate of axon elongation, and may be independently regulated. In this study, we used time-lapse digital microscopy and custom-designed analytic software to assess the effects of ethanol on the growth of axons from embryonic rat hippocampal pyramidal neurons in culture during 24 h of development, beginning approximately 7 h after plating. We recorded the amount of time elapsed before axons emerged, the relative amount of time spent in periods of growth and nongrowth, and the rate and direction of change in axon length during both periods of growth and nongrowth. The initiation of axonal outgrowth was significantly delayed by ethanol in a dose-dependent fashion at concentrations in the medium at or above 100 mg/dl. However, once established, axons exhibited accelerated growth in the presence of ethanol. This increase in overall growth rate was primarily due to a significant decrease in axon retraction during nongrowth periods. Ethanol did not affect the duration or frequency of growth and nongrowth periods. We propose, therefore, that mechanisms underlying ethanol-mediated changes in axon growth are linked to signaling events that differentially regulate outgrowth and retraction.