Functional Outcomes of Cubital Tunnel Release in Patients with Negative Electrodiagnostic Studies.

BACKGROUND: Cubital tunnel syndrome (CuTS) is the second most common compression neuropathy of the upper extremity. Electrodiagnostic studies (EDSs) are often used to confirm diagnosis. However, negative EDSs can present a difficult clinical challenge. The purpose of this study was to determine the functional outcomes and symptom improvement for patients with a clinical diagnosis of CuTS, but with negative EDSs, who are treated surgically. METHODS: Patients who had EDSs before ulnar nerve surgery were identified by means of database search. Chart review was performed on 867 cases to identify those with negative EDSs. Twenty-five ulnar nerve operations in 23 patients were included in analysis. Chart review was performed to record preoperative and postoperative symptoms, physical examination findings, and outcome measures (ie, Disabilities of the Arm, Shoulder and Hand questionnaire and the Patient-Rated Ulnar Nerve Evaluation). RESULTS: At a mean follow-up period of 20.7 ± 14.9 months, 15 of 25 cases (60.0%) had complete resolution of all preoperative symptoms. All 10 patients who had residual symptoms endorsed improvement in their preoperative complaints. The median preoperative Disabilities of the Arm, Shoulder and Hand score was 40.0 [interquartile range (IQR), 23.9 to 58.0], which significantly decreased to a median of 6.8 (IQR, 0 to 22.7) at final follow-up ( P < 0.01). The median postoperative Patient-Rated Ulnar Nerve Evaluation score was 9.5 (IQR, 1.5 to 19.5). CONCLUSIONS: Patients with CuTS and normal EDSs treated surgically can be expected to have favorable outcomes with respect to symptoms and improvement in functional outcome scores. After ruling out confounding diagnoses, the authors continue to offer surgical intervention for these patients when nonoperative treatment has failed. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Cervical spinal cord injury-induced neuropathic pain in male mice is associated with a persistent pro-inflammatory macrophage/microglial response in the superficial dorsal horn.

A significant portion of individuals living with traumatic spinal cord injury (SCI) experiences some degree of debilitating neuropathic pain (NP). This pain remains largely intractable in a majority of cases, due in part to an incomplete understanding of its underlying mechanisms. Central sensitization, an increase in excitability of pain transmission neurons located in superficial dorsal horn (sDH), plays a key role in development and maintenance of SCI-induced NP. Resident microglia and peripheral monocyte-derived macrophages (referred to collectively as MMΦ) are involved in promoting SCI-induced DH neuron hyperexcitability. Importantly, these MMΦ consist of populations of cells that can exert pro-inflammatory or anti-inflammatory signaling within injured spinal cord. It is critical to spatiotemporally characterize this heterogeneity to understand MMΦ contribution to NP after SCI. Given that a majority of SCI cases are cervical in nature, we used a model of unilateral C5/C6 contusion that results in persistent at-level thermal hyperalgesia and mechanical allodynia, two forms of NP-related behavior, in the forepaw. The aim of this study was to characterize the sDH MMΦ response within intact cervical spinal cord segments caudal to the lesion (i.e. the location of primary afferent nociceptive input from the forepaw plantar surface). Cervical SCI promoted a persistent MMΦ response in sDH that coincided with the chronic NP phenotype. Using markers of pro- and anti-inflammatory MMΦ, we found that the MMΦ population within sDH exhibited significant heterogeneity that evolved over time post-injury, including a robust and persistent increase in pro-inflammatory MMΦ that was especially pronounced at later times. C5/C6 contusion SCI also induced below-level thermal hyperalgesia and mechanical allodynia in the hindpaw; however, we did not observe a pronounced MMΦ response in sDH of L4/L5 spinal cord, suggesting that different inflammatory cell mechanisms occurring in sDH may be involved in at-level versus below-level NP following SCI. In conclusion, our findings reveal significant MMΦ heterogeneity both within and across pain transmission locations after SCI. These data also show a prominent and persistent pro-inflammatory MMΦ response, suggesting a possible role in DH neuron hyperexcitability and NP.

Compact U

We propose a bosonic U^{κ}(1) rotor model on a three dimensional spacetime lattice. With the inclusion of a Maxwell term, we show that the low-energy properties of our model can be obtained reliably via a semiclassical approach. Those properties are the same as that of the Chern-Simons field theory, S=∫d^{3}x(K_{IJ}/4π)A_{I}dA_{J}. We require the lattice variables on each link to be compact (i.e., take values on circles), which enforces the quantization of the K matrix as a symmetric integer matrix with even diagonals. Our lattice model also has exact 1-symmetries, which gives rise to the 1-form symmetry in the Chern-Simons field theory. In particular, some of those 1-symmetries are anomalous (i.e., non-on-site) in the expected way. The anomaly can be probed via the breaking of those lattice 1-symmetries by the boundaries.

Y-site compatibility of vancomycin and piperacillin/tazobactam at commonly utilized pediatric concentrations.

BACKGROUND: Vancomycin and piperacillin/tazobactam are common empiric antibiotics in hospitalized pediatric patients. Studies evaluating intravenous (IV) compatibility at various concentrations show inconsistent results. OBJECTIVE: The objective of this study was to determine the Y-site compatibility of vancomycin 10 mg/mL and piperacillin/tazobactam 112.5 mg/mL. METHODS: Vancomycin (10 g vial) was reconstituted using sterile water for injection (SWFI) and diluted with 5% dextrose in water (D5W) to a final concentration of 10 mg/mL in an evacuated IV bag. Piperacillin/tazobactam (40.5 g vial) was reconstituted and diluted with SWFI to a final concentration of 112.5 mg/mL (100 mg/mL piperacillin) in an evacuated IV bag. Both antibacterial stock solutions were then stored in a refrigerator at 4°C (39.2°F). Initial solution appearances, including color, clarity, and particulates, were documented. Diluted solutions were mixed in a quantity of 3 mL of each vancomycin and piperacillin/tazobactam in glass test tubes. Subsequent evaluation included pH assessment and visual evaluation with unaided eye, magnifying glass, high-beam light, and via Spec-20 turbidimeter. Solution mixtures were evaluated upon mixing and again at 30 minutes, 1 hour, and 4 hours after mixing. RESULTS: Initial combination of vancomycin and piperacillin/tazobactam resulted in a milky precipitate, visible to the unaided eye, which dissipated 15 seconds after mixing. No precipitate was visualized via any method at any additional time point. Turbidimetry and pH readings did not demonstrate differences from baseline measurements. CONCLUSIONS: A combination of vancomycin 10 mg/mL and piperacillin/tazobactam 112.5 mg/mL demonstrated precipitation immediately upon mixing. Co-infusion of vancomycin and piperacillin/tazobactam via Y-site should be considered incompatible.

Tris(5-methylpyrazolyl)methane: synthesis and properties of its iron(II) complex.

The new ligand, tris(5-methylpyrazolyl)methane (1), has been prepared by the reaction of n-butyl lithium with tris(pyrazolyl)methane followed by trimethylation of the tetralithiated species with methyl iodide. The BF(4)(-), ClO(4)(-), and BPh(3)CN(-) salts of the Fe(II) complex of this ligand were also synthesized. The X-ray crystal structure of the BF(4)(-) complex (2) at 100 K had Fe-N bond lengths of 1.976 Å, indicative of a low spin Fe(II) complex, while at room temperature, the structure of this complex had a Fe-N bond distance close to 2.07 Å, indicative of an admixture of approximately 50% low-spin and 50% high-spin. The solid-state structure of the complex with a ClO(4)(-) counterion was determined at 5 different temperatures between 173 and 293 K, which allowed the thermodynamic parameters for the spin-crossover to be estimated. Mössbauer spectra of the BF(4)(-) complex further support spin-state crossover in the solid state with a transition temperature near 300 K. UV-visible spectroscopy and (1)H NMR studies of 2 show that the transition temperature in solution is closer to 400 K. No spin-crossover was observed for [Fe(1)(2)](2+)·2BPh(3)CN(-). The results allow the separation of effects of groups in the 3-position from those in the 5-position on tpm ligands, and also point toward a small cooperative effect in the spin-crossover for the Fe(II) complex.

Upper limb nerve entrapment syndromes in veterans with lower limb amputations.

OBJECTIVE: To examine the prevalence and severity of upper limb entrapment syndromes in a sample of veterans with lower limb amputations. DESIGN: A descriptive survey, pilot study. SETTING: 2008 National Disabled Veterans Winter Sports Clinic. PARTICIPANTS: Twenty participants with various lower limb amputations. METHODS: All study participants completed a questionnaire that included symptoms of both upper limbs, medical history, time since amputation, medication history, use of assistive technology, and wheelchair characteristics. A physical examination and electrodiagnostic testing were then performed on each participant. The physical examination included an assessment of bilateral upper limb weakness or sensory abnormalities, thenar/hypothenar atrophy, deep tendon reflexes, Tinel test of the wrist and elbow, and the Phalen maneuver. All nerve conduction studies were performed by an American Board of Electrodiagnostic Medicine-certified physiatrist. OUTCOME MEASURES: Correlation between symptoms, examination findings, and electrodiagnostic findings with the participant's demographic data in the questionnaire. RESULTS: Twenty participants (19 men and 1 woman) were enrolled in the study, with a total of 38 upper limbs evaluated. The mean age of the study population was 59 +/- 13 years, with an average of 23 years since the amputation. Sixteen (80%) of 20 participants had electrodiagnostic findings consistent with median neuropathy across the wrist (26/38 affected limbs, 6 participants with unilateral and 10 with bilateral findings), and 14 (70%) of 20 participants had ulnar entrapment neuropathy across the elbow (22/38 affected limbs, 6 participants with unilateral and 8 with bilateral findings). Several participants (6 of 20, 30%) were found to have electrodiagnostic evidence of ulnar entrapment neuropathy across the wrist (10 of 38 affected limbs, 2 participants unilateral and 4 bilateral findings). CONCLUSION: A high number of veterans with lower limb amputations presented with upper limb nerve entrapment syndromes. Careful attention to these nerve entrapment syndromes in lower limb amputees is necessary because the symptoms may be confounded by other chronic pain-related disorders.

Cognitive effects of dexamethasone at high altitude.

OBJECTIVE: The major therapeutic effect of dexamethasone on persons affected by high-altitude illness may be upon vascular leakiness with a consequent decrease in cerebral edema. We set out to determine if dexamethasone ameliorates the cognitive/psychomotor effects of acute exposure to high altitude on asymptomatic subjects. METHODS: Six adult subjects were tested at baseline (2500 m) with standard, computerized cognitive and psychomotor tests. Over the next 4 days, subjects were acclimatized to an altitude of 3700 m. On the fifth day, subjects ascended to 4800 m where predexamethasone testing was administered. No subject had symptoms of frank altitude illness at 4800 m. To limit acclimatization, subjects descended to 3700 m within 4 hours. The first 4-mg dose of oral dexamethasone was given in the evening of day 5. A second 4-mg dose of dexamethasone was given the following morning, and subjects reascended to 4800 m where postdexamethasone testing was performed. RESULTS: All cognitive and psychomotor tests showed improved reaction times in subjects who were given dexamethasone. Mean reaction time (+/- SD) for shape recognition went from 1.20 +/- 0.36 seconds at 2500 m to 1.40 +/- 0.37 seconds at 4800 m. After dexamethasone administration, mean shape recognition time declined to 1.26 +/- 0.32 seconds (P = .052). CONCLUSION: These data show a trend toward decreased cognitive deficits in subjects pretreated with dexamethasone. One possibility for this trend is that cognitive deficits in otherwise asymptomatic subjects exposed to high altitude are caused by subclinical cerebral edema.