Adductor Pollicis Research Articles

Reconstructing Pinch Strength after Ulnar Nerve Injury by Transferring the Opponens Pollicis Motor Branch.

With ulnar nerve injuries, paralysis of the first dorsal interosseous and adductor pollicis muscle weakens the patient's pinch. In the palm, we transferred the opponens pollicis motor branch to the deep terminal division of the ulnar nerve for pinch reconstruction. Sixteen patients with ulnar nerve injuries around the elbow underwent reconstruction and were followed up postoperatively for a minimum of 14 months. Their mean age was 41 ± 16 years, and the mean interval between injury and surgery was 134 ± 126 days (range, 2 to 390 days). Preoperatively and postoperatively, grasp, key, and subterminal key pinch strength were measured using dynamometers. Reinnervation of the first dorsal interosseous muscle was observed in 15 of the 16 patients. Mean grasp strength improved from 15.5 ± 8.5 kg preoperatively to 24 ± 10 kg postoperatively, achieving 57% ± 16% of contralateral hand strength. Preoperatively, terminal key pinch averaged 3 ± 1 kg, which improved postoperatively to 5.5 ± 2 kg, achieving 71 ± 24% of the strength measured contralaterally. Preoperatively to postoperatively, subterminal key pinch force increased from 0 to 2.4 ± 1.3 kg, achieving 61% ± 27% that of the unaffected side. Patients who underwent surgery within 6 months of their injury showed a mean subterminal key pinch strength recovery of 63% ± 27% of the normal side, whereas those who underwent surgery between 7 and 13 months after injury showed a mean subterminal key pinch strength recovery of 51% ± 29%. Transferring the opponens pollicis motor branch to the deep terminal division of the ulnar nerve improved pinch and grasp strength without jeopardizing thumb function. Therapeutic, IV.

Measurement of the lumbrical muscle activity of the hand using electromyography supported by the ultrasound imaging technique with string navigation

Although placing surface electrodes on small muscles by palpation is difficult, ultrasound guidance may enable electrode placement on the small muscles. This study aimed to examine whether ultrasound guidance is helpful for placement of electrodes on a small muscle, such as the hand lumbrical muscle. Twelve dominant hands of 12 healthy right-handed adults were included in this study. The first lumbrical muscle belly of the hands was identified using ultrasound guidance with a string navigation technique for placing surface electrodes. This technique was designed to identify the location of the center of the muscle belly under ultrasound imaging using a string. After the electrodes were placed on the muscle belly using this technique, the surface electromyographic signals of the first lumbrical, first dorsal interosseous, and adductor pollicis muscles were recorded. The activity of the lumbrical muscle could be separately measured of the first dorsal interosseous and adductor pollicis muscles. This technique has the potential to enable surface electromyography of small muscles for which placement of surface electrodes by palpation is challenging.

Influence of levodopa use on the nutritional status o folder adults with Parkinson’s disease

This study aimed to assess the effect of levodopa on the nutritional status of older adults with Parkinson’s disease (PD) and associated factors. This cross-sectional, analytical, descriptive, observational study collected sociodemographic, clinical, and levodopa daily dose data and conducted nutritional assessment with the Mini-Nutritional Assessment (MNA) and adductor pollicis muscle thickness (APMT). The chi-square test was used to compare proportions and independence, considering p<0.05. The study sample comprised 40 older adults with PD, with a mean age of 69.4±7.6 years; 70% were males. MNA verified a prevalence of malnutrition among those with more than 10 years with the disease, in an advanced stage, and whose levodopa equivalent daily dose was above 600 mg. It was verified that having chronic comorbidities may significantly increase the risk of malnutrition according to the APMT classification. Hence, it is greatly important to assess the nutritional status in the follow-up of older adults with PD to diagnose malnutrition early and ensure assertive and multidisciplinary intervention.

Intraoperative electromyographic monitoring in children using a novel pediatric sensor.

Train-of-four (TOF) monitoring is essential in optimizing perioperative outcomes as a means to assess the depth of neuromuscular blockade and confirm recovery following the administration of neuromuscular blocking agents (NMBAs). Quantitative TOF monitoring has been limited in infants and children primarily due to lack of effective equipment. The current study evaluates a novel electromyography (EMG)-based TOF monitor with a recently developed pediatric-sized self-adhesive sensor in infants and children. Consented pediatric patients undergoing inpatient surgery requiring the administration of NMBAs were enrolled. The EMG electrode was placed along the ulnar nerve on the volar aspect of the distal forearm. The muscle action potentials from the adductor pollicis muscle were recorded throughout surgery at 20-second intervals. Data from the monitor's built-in memory card were later retrieved and analyzed. The final study cohort included 51 patients who ranged in age from 0.2 to 7.9 years and in weight from 4.2 to 36.0 kilograms. Thirty patients weighed less than 15 kgs. Supramaximal stimulus current intensity (mA) at a pulse width of 200 μsec was 30 mA in 8%; 40 mA in 29%; 50 mA in 16%; and 60 mA in 20% of the patients. Supramaximal stimulus current intensity (mA) at a pulse width of 300 μsec was 50 mA in 4%; 60 mA in 24%. The muscle action potential baseline amplitude was 8.7 ± 3.3 mV and recovered to 7.2 ± 3.7 mV after antagonism of neuromuscular blockade. The average baseline TOF ratio was 100 ± 3% and recovered to 98 ± 7% after antagonism of neuromuscular blockade. No technical issues were noted with application of the sensor or subsequent use of the monitor. Neuromuscular monitoring can be performed intraoperatively in pediatric patients who are less than 8 years of age using a novel commercially available EMG-based monitor with a recently developed pediatric sensor. The novel sensor allows use of an EMG-based monitor in infants and children in whom acceleromyography or subjective (visual) observation of the TOF response may not be feasible. Automatic detection of neuromuscular stimulating parameters (supramaximal current intensity level, baseline amplitude of the muscle action potential) was feasible in pediatric patients of all sizes including those weighing less than 15 kilograms or when there was limited access to the extremity being monitored.

Evaluation of a Protocol for the Management of Maintenance and Reversal of Rocuronium Block Using Neostigmine or Sugammadex.

Postoperative residual neuromuscular blockade (PRNB) is defined as an adductor pollicis train-of-four ratio (TOFR) <0.9. It is a common postoperative complication when nondepolarizing muscle relaxants are either not reversed or reversed with neostigmine. PRNB has been reported in 25% to 58% of patients who receive intermediate-acting nondepolarizing muscle relaxants, and it is associated with increased morbidity and decreased patient satisfaction. We conducted a prospective descriptive cohort study during the implementation of a practice guideline that included the selective use of sugammadex or neostigmine. The primary study aim of this pragmatic study was to estimate the incidence of PRNB at arrival to the postanesthesia care unit (PACU) when the practice guideline is followed. We enrolled patients undergoing orthopedic or abdominal surgery requiring neuromuscular blockade. Rocuronium administration was guided by surgical requirements and based on ideal body weight, with dose reductions for women and/or age >55 years. Only qualitative monitoring was available to the anesthesia providers, and selection of sugammadex or neostigmine was guided by tactile assessments of the response to train-of-four (TOF) stimulation by a peripheral nerve stimulator. Neostigmine was administered if no fade was detected in the TOF response at the thumb. Deeper blocks were reversed with sugammadex. The prespecified primary and secondary end points were the incidence of PRNB at arrival to the PACU, defined as a normalized TOFR (nTOFR) < 0.9, and severe PRNB, defined as nTOFR <0.7 on arrival to the PACU. Anesthesia providers were blinded to all quantitative measurements made by research staff. Analysis included 163 patients, and 145 underwent orthopedic and 18 abdominal surgeries. Of the 163 patients, 92 (56%) were reversed with neostigmine and 71 (44%) with sugammadex. The overall incidence of PRNB at PACU arrival was 5 of 163 or 3% (95% confidence interval [CI], 1-7). The incidence of severe PRNB in PACU was 1% (95% CI, 0-4). Three of the 5 subjects with PRNB had TOFR <0.4 at time of reversal but were given neostigmine since anesthesia providers detected no fade by qualitative assessment. The use of a protocol that specifies rocuronium dosing and selective use of sugammadex versus neostigmine based on qualitative assessment of TOF count and fade allowed us to achieve an incidence of PRNB of 3% (95% CI, 1-7) at PACU arrival. Quantitative monitoring may be needed to further reduce this incidence.

Comparison of visual and electromyographic assessments with train-of-four stimulation of the ulnar nerve: a prospective cohort study.

The use of a peripheral nerve stimulator to assess the level of neuromuscular blockade tasks the anesthesia clinician with subjectively assessing the response to neurostimulation. In contrast, objective neuromuscular monitors provide quantitative information. The purpose of this study was to compare subjective evaluations from a peripheral nerve stimulator with objective measurements of neurostimulation responses from a quantitative monitor. Patients were enrolled preoperatively, and intraoperative neuromuscular blockade management was at the discretion of the anesthesiologist. Electromyography electrodes were placed over the dominant or nondominant arm in a randomized fashion. Following onset of nondepolarizing neuromuscular blockade, the ulnar nerve was stimulated, the response was measured with electromyography, and anesthesia clinicians, who were blinded to the objective measurements, subjectively (visually) evaluated the response to neurostimulation. Fifty patients were enrolled and 666 neurostimulations were performed at 333 different time points. Anesthesia clinicians subjectively overestimated the response of the adductor pollicis muscle following neurostimulation of the ulnar nerve 155/333 (47%) of the time when compared with objective electromyographic measurements. When subjective evaluations and objective measurements differed to any degree, subjective evaluations were higher than objective measurements 155/166 (92%) of the time (95% CI, 87 to 95; P < 0.001), representing significant evidence that subjective evaluation overestimates the response to train-of-four stimulation. Subjective observations of a "twitch" do not consistently correspond to objective measurements of neuromuscular blockade with electromyography. Subjective evaluation overestimates the response to neurostimulation and may be unreliable for determining the depth of block or confirming adequate recovery.

The effect of β-hydroxy β-methylbutyrate (HMB) with nutritional counselling on anthropometric muscle mass markers, strength, functionality, and quality of life in patients on the waiting list for liver transplantation: A double-blind study

ObjectivePatients on the waiting list for liver transplantation (LTx) usually lose muscle mass. Supplementation with β-hydroxy β-methylbutyrate (HMB) may have a promising effect on this clinical condition. This study aimed to evaluate the effects of HMB on muscle mass, strength, functionality, and quality of life in patients on the LTx waiting list. MethodsA double-blind, randomized study was conducted of 3g supplementation of HMB or 3g supplementation of maltodextrin (active control) with nutritional counselling for 12 wk in patients >18 y, evaluated at five points or timepoints. Body composition and anthropometric data (resistance, reactance, phase angle, weight, body mass index, arm circumference [AC], arm muscle area, and adductor pollicis muscle thickness) were collected, and muscle strength was assessed through dynamometry and muscle function by the frailty index (FI). Quality of life was assessed. ResultsA total of 47 patients were enrolled (HMB: 23 and active control: 24). There was a significant difference in both groups for AC (P = 0.03), dynamometry (P = 0.02), and FI (P = 0.01). There was an increase in dynamometry between weeks 0 and 12 in both groups (HMB [Δdynamometry: 10.1% ± 16.4%; P < 0.05] and active control [Δdynamometry: 23.0% ± 70.3%; P < 0.05]). The AC increased in both groups between weeks 0 and 4 (HMB [ΔAC: 0.9% ± 2.8%; P < 0.05] and active control [ΔAC: 1.6% ± 3.6%; P < 0.05]) and between weeks 0 and 12 (HMB [ΔAC: 3.2% ± 6.7%; P < 0.05] and active control [ΔAC: 2.1% ± 6.6%; P < 0.05]). The FI decreased in both groups, between weeks 0 and 4 (HMB [ΔFI: –4.2% ± 6.9%; P < 0.05) and active control [ΔFI: –3.2% ± 9.6%; P < 0.05]) and between weeks 0 and 12 (HMB ΔFI: –4.4% ± 11.2%; P < 0.05] and active control [ΔFI: –5.5% ± 11.3%; P < 0.05]). The other variables did not change (P > 0.05). ConclusionsNutritional counselling with supplementation with HMB or active control in patients on the LTx waiting list improved AC, dynamometry, and the FI in both groups.

A case series of Stener’s lesion of the first metacarpophalangeal joint

Ulnar collateral ligament (UCL) injuries have a high prevalence however; these are usually being missed in the initial clinical evaluation. Depending on the chronicity of the injury there are two acronyms for UCL tear. One is the skier's thumb and the other is the gamekeeper's thumb. If the UCL of the first metacarpophalangeal joint (MCP joint) has a complete tear with entrapment of aponeurosis of adductor pollicis muscle between the MCP joint and torn ligament, is called a Stener’s lesion. This is a rare clinical entity that requires early surgical correction because of entrapment. The mechanism of injury is the coerced abduction of the thumb from the index finger, causing ligament tears or sprain with or without ensuing avulsion fracture. The incidence of Stener’s lesions associated with UCL rupture has been reported to be up to 52% per intra-operative finding. In Stener’s lesions, the UCL tears from the base of the proximal phalanx (PP) then retracts proximally and displaces superficial to the adductor pollicis. Here we are presenting four cases of Stener’s lesions, with the usefulness of magnetic resonance imaging (MRI) in diagnosing this entity, which can prevent possible long-term complications such as chronic pain, joint degeneration, and joint instability.

Comparison of Two Doses of Cisatracurium (0.15mg/Kg and 0.2mg/Kg) in a Single Centre, Prospective, Comparative, Parallel Group of Patients Undergoing General Anesthesia with Endotracheal Intubation by Studying Ease of Intubation

Objective : Study the advantages and pitfalls of both 0.15 mg/kg and 0.2 mg/kg of Cisatracurium for Intubation. Background: The patients coming to a Tertiary Care Hospital during period 2018-2019 for surgery under General Anaesthesia, who met the Inclusion Criteria were studied in a hundred patients. After giving all components of balanced general anaesthesia, patients randomised into 2 groups either 0.15 mg/kg or 0.2mg/kg of Cisatracurium as a muscle relaxant and Intubation was done at 3 minutes. Measurements and Results: Heart rate, Blood pressure, Systolic, Diastolic, Mean, SpO2, ETCO2, TOF monitoring at the adductor pollicis, and BIS were monitored for 7 minutes and Intubating conditions in both the groups were evaluated, and scored according to the Steyn’s Modification of Helbo-Hansen Scoring system. In haemodynamic changes in Group A [0.15 mg/kg] Heart rate and Blood pressure showed an increasing trend before coming down to baseline by 7 minutes. In Group B [0.2mg/kg] the trend was decreasing from baseline after a minor increase in heart rate at 2 minutes and Mean Blood pressure was lower at all intervals when compared to baseline. Regarding Intubation In Group A maximum number of participants were having good score (56%) followed by poor (30%) and excellent (14%) whereas in Group B excellent score was maximum (62%) followed by good (32%) and poor (6%). With respect to Train of four stimulation Group B showed decreased response to neuromuscular stimulation from 3 minutes onwards compared to Group A. Bispectral index monitoring, in both groups, showed a decreasing trend at every time interval. Conclusion: Cisatracurium is a potent non-depolarising neuromuscular blocking agent and tracheal intubation can be accomplished with good to excellent intubating conditions according to Steyn’s Modification of Helbo-Hansen Scoring System at 3 minutes following 0.15 mg/kg and 0.2 mg/kg of Cisatracurium. From the study of 100 patients in 2 groups, we found that Cisatracurium in a dose of 3ED95 (0.15mg/kg) has haemodynamic stability in view of Heart rate and Blood Pressure. Cisatracurium at a dose of 0.2mg/kg was more haemodynamically stable than Cisatracurium at 0.15 mg/kg during intubation.

Comparison of Relaxometry Between Ulnar Nerve and Posterior Tibial Nerve After Cisatracurium Administration Using Electromyography.

Electromyography can be used for quantitative neuromuscular monitoring during general anesthesia, mostly using the stimulation train-of-four (TOF) pattern. Relaxometry measures the muscular response of the adductor pollicis muscle to electrical stimulation of the ulnar nerve, which is routinely used in clinical practices for monitoring the neuromuscular block. However, when it is not always possible to be used for all patients, the posterior tibial nerve is a suitable alternative. Using electromyography, we compared the neuromuscular block between the ulnar and the posterior tibial nerves. In this study, the participants were 110 patients who met inclusion criteria and submitted their written consent. Following the administration of cisatracurium intravenously, the patients had relaxometry performed simultaneously on the ulnar and the posterior tibial nerves using electromyography. Eighty-seven patients were included in the final analysis. The onset time was 296 ± 99 s at the ulnar nerve and 346 ± 146 s at the tibial nerve, with a mean difference of -50 s and a standard deviation of 164 s. The 95% limits of agreement ranged from -372 s to 272 s. The relaxation time was 105 ± 26 min at the ulnar nerve and 87 ± 25 min at the tibial nerve, with a mean difference of 18 min and a standard deviation of 20 min. Using electromyography, no statistically significant difference was noticed between the ulnar and the posterior tibial nerve during the neuromuscular block. The onset time and the relaxation time assessed with an electromyogram to compare the stimulation of the ulnar and posterior tibial nerves showed large limits of agreement.

Generation and analysis of synthetic surface electromyography signals under varied muscle fiber type proportions and validation using recorded signals.

The magnitude and duration of muscle force production are influenced by the fiber type proportion. In this work, surface electromyography (sEMG) signals of muscles with varied fiber type proportions, are generated. For this, relevant components of existing models reported in various literature have been adopted. Also, a method to calculate the motor unit size factor is proposed. sEMG signals of adductor pollicis (AP) and triceps brachii (TB) muscles are simulated from the onset of force production to muscle fatigue state at various percentages of maximal voluntary contraction (MVC) values. The model is validated using signals recorded from these muscles using well-defined isometric exercise protocols. Root mean square and mean power spectral density values extracted from the simulated and recorded signals are found to increase for TB and decrease for AP with time. A linear variation of the features with %MVC values is obtained for simulated and experimental results. The Bland-Altman plot is used to analyze the agreement between simulated and experimental feature values. Good agreement is obtained for the feature values at various %MVCs. The mean endurance time calculated using the model is found to be comparable to that of the experimental value. This method can be used to generate sEMG signals of different muscles with varying fiber type ratios under various neuromuscular conditions.

Intramuscular Neural Distribution of Adductor Pollicis Muscle Spasticity in Cadaver Model Regarding Botulinum Neurotoxin Treatment.

The adductor pollicis muscle is frequently targeted for botulinum neurotoxin injective treatment for spasticity. However, there are no injective guidelines for delivering injection to the muscle. A method known as the modified Sihler's method was used to stain the adductor pollicis muscle in 16 specimens to reveal intramuscular neural distribution of the muscle. The most intramuscular neural distribution was located on 1/5 to 3/5 of the muscle regarding midline of 3rd metacarpal bone (0) to the base of the 1st proximal phalanx (5/5). The nerve entry point was mostly located on 0 to 1/5 of the muscle. The result suggests that botulinum neurotoxin should be delivered at the middle of second metacarpal bone via deep injection.

Measuring Success of Patient Safety Initiatives: The 2023 American Society of Anesthesiologists Practice Guidelines for Monitoring and Antagonism of Neuromuscular Blockade

Measuring Success of Patient Safety Initiatives: The 2023 American Society of Anesthesiologists Practice Guidelines for Monitoring and Antagonism of Neuromuscular Blockade

This Month in Anesthesiology

This Month in Anesthesiology

Sex-Related Neuromuscular Adaptations to Youth Obesity: Force, Muscle Mass, and Neural Issues.

Young obese are generally stronger than their typically developing counterparts. Strength differences could be partly ascribed to nervous adaptations, due to the loading effect of carrying overweight. We hypothesized that central adaptations of the muscles highly involved in weight bearing, i.e., plantar flexors (PF) and knee extensors (KE) could be greater in girls than boys due to their reduced potential for muscle hypertrophy. Furthermore, it is possible that neuromuscular adaptations in weight-bearing muscles will be greater compared to the unloaded muscles such as the adductor pollicis (AP).Twenty-four non-obese and 21 obese (body mass index: 33±4kg·m-2) adolescent girls and boys (12-15years) performed maximal voluntary isometric contractions (MVC) of the PF and KE muscles. Voluntary activation (VA), assessed with the twitch interpolation technique, the antagonist co-activation (Co-Act) level, and the normalized root-mean-square value (RMS) of the agonist muscles were measured to account for central adaptations.The results revealed a weight status effect (p<0.001) on the absolute MVC torque and VA of both KE and PF muscles. Moreover, these differences were also related to the sex of the participants (p<0.05) for the PF muscles. While the VA, absolute, and specific MVC torque were greater in obese compared with non-obese girls, no difference was found between boys. A similar Co-Act level was observed between groups, whatever the sex and muscle group considered. Finally, no significant differences were found for the AP regarding peripheral and neural factors.This study highlighted a favorable effect of obesity on the central mechanisms (i.e., VA) responsible for force production within the lower limb muscles. However, obesity-related central adaptation was only observed in girls for the PF muscles. Thus, the excess of body mass supported by the muscles involved in weight-bearing could act as a chronic training stimulus responsible for these adaptations in obese adolescents but mostly in girls.

Combined Endurance and Strength or Only Endurance Training? Effects of Training Mode on Neuromuscular Characteristics and Functional Abilities in Obese Adolescent Girls Enrolled in a Weight-Reduction Program.

The aim of the present study was to examine whether combining strength and endurance training would promote better improvements in neuromuscular characteristics and functional abilities than endurance training alone in obese adolescent girls enrolled in a weight-reduction program. Twenty-four obese adolescent girls (12-15years) volunteered to participate in a 9-month training program. Participants were allocated into two groups following either (i) combined training (endurance+strength; E+ST) or (ii) endurance training (ET) program. Absolute and specific maximal torque, muscle size, and maximal voluntary activation level (VA) of the knee extensor (KE) and plantar flexor (PF) muscles were assessed. Moreover, functional abilities such as balance and fatigability during a maximal isometric intermittent contraction test of the KE muscles were measured before and after the intervention. The force of the adductor pollicis (AP) muscles was used as a control to account for any effect of growth or mechanical unloading on neuromuscular properties and muscle size. While absolute and specific torque of the KE (+14.7±12.1% and +14.4±15.5%; p<0.05) and PF (+19.2±16.7% and +18.3±17.5%; p<0.001) muscles increased in the E+ST group, PF torque decreased, and KE torque did not change in the ET group (-22.6±10.5% and -15.0±17.2%; p<0.001). Moreover, the VA of the KE muscles increased for the E+ST (+6.1±5.6%; p<0.01) group and decreased for the ET group (-5.4±5.4%; p<0.05). In contrast, VA remained similar in the PF muscles for both groups. The number of repetitions during the fatigability test increased in the ET group (38.4±22.3 vs. 84.1±33.3; p=0.032) and was unchanged in the E+ST group (50.8±14.1 vs. 54.2±37.8), but it was associated with a higher force level. Moreover, balance improved in the E+ST group, but not in the ET group. To conclude, physical training combining strength and endurance training promoted larger improvement in neuromuscular characteristics and functional abilities than endurance training alone in obese adolescent girls. Greater neuromuscular adaptations resulting from the E+ST training may be beneficial for preserving or even increasing functional abilities and possibly induce greater engagement in the active lifestyle of obese adolescents. However, the endurance component seems necessary in training programs to reduce fatigability during daily living activities.

BIOMECHANICAL EVALUATION OF PNEUMATIC SLEEVE ORTHOSIS FOR LOFSTRAND CRUTCHES.

Crutch walking, especially when using a swing-through gait pattern, is associated with high, repetitive joint forces, hyperextension/ulnar deviation of the wrist, and excessive palmar pressure that compresses the median nerve. To reduce these adverse effects, we designed a pneumatic sleeve orthosis that utilized a soft pneumatic actuator and secured to the crutch cuff for long-term Lofstrand crutch users. Eleven able-bodied young adult participants performed both swing-through and reciprocal crutch gait patterns with and without the custom orthosis for comparison. Wrist kinematics, crutch forces, and palmar pressures were analyzed. Significantly different wrist kinematics, crutch kinetics, and palmar pressure distribution were observed in swing-through gait trials with orthosis use (p<0.001, p=0.01, p=0.03, respectively). Reductions in peak and mean wrist extension (7%, 6%), wrist range of motion (23%), and peak and mean ulnar deviation (26%, 32%) indicate improved wrist posture. Significantly increased peak and mean crutch cuff forces suggest increased load sharing between the forearm and cuff. Reduced peak and mean palmar pressures (8%, 11%) and shifted peak palmar pressure location toward the adductor pollicis denote a redirection of pressure away from the median nerve. In reciprocal gait trials, non-significant but similar trends were observed in wrist kinematics and palmar pressure distribution, whereas a significant effect of load sharing was noticed (p=0.01). These results suggest that Lofstrand crutches modified with orthosis may improve wrist posture, reduce wrist and palmar load, redirect palmar pressure away from the median nerve, and thus may reduce or prevent the onset of wrist injuries.

Calf circumference is an independent predictor of postoperative complications in the surgical treatment of head and neck cance

Introduction: The prevalence of malnutrition is high among head and neck cancer (HNC) patients and negatively impacts their quality of life, treatment, and survival rates. Objective: To identify preoperative nutritional variables capable of predicting postoperative complications in surgically treated HNC patients. Methods: This was a prospective cohort study of HNC patients referred for surgery as initial treatment. Results: Sixty patients were included in the study; they had a median age of 65.5 years, were mostly men (85%), and most had low education levels (90%) and low household income (78.3%). The incidence rate of severe postoperative complications (grades II, III, IV, and V according to the Clavien-Dindo grading system) was found to be 50%. The nutritional variables under investigation, namely calf circumference (CC), triceps skinfold, body mass index, and adductor pollicis muscle thickness were shown to predict postoperative complications in HNC patients, especially CC, which was found to be an independent predictor of complications (OR=0.8; 95%CI: 0.65–0.96). Each 1-cm increase in calf circumference was associated with a 20% decrease in the risk of postoperative complications. Conclusion: Our findings show the nutritional variables studied are useful in the prognostic assessment of HNC surgery.

Comparison of contralateral acceleromyography and electromyography for posttetanic count measurement.

Electromyography has advantages over mechanomyography and acceleromyography. Previously, agreement of the train-of-four counts between acceleromyography and electromyography was found to be fair. The objective of this study was to assess the agreement of posttetanic count including agreement of neuromuscular blockade status (intense block; posttetanic count = 0 or deep block; posttetanic count ≥ 1 and train-of-four count = 0) between acceleromyography and electromyography. Thirty-six patients, aged 20-65 years, participated in this study. Rocuronium 0.6 mg/kg, with additional dose of 0.3 mg/kg if required, was administered to the patients. The train-of-four and posttetanic counts were monitored in the contralateral arm using electromyography at the first dorsal interosseus or adductor pollicis, and acceleromyography at the adductor pollicis. Posttetanic count measurements were performed at 6 min intervals; the responses were recorded until the train-of-four count reached 1. We evaluated the agreement of degree of neuromuscular blockade (intense or deep block) and that of posttetanic count between acceleromyography and electromyography. We analyzed 226 pairs of measurements. The percentage agreement indicating the same neuromuscular blockade status (intense or deep block) between acceleromyography and electromyography was 73%. Cohen's kappa coefficient value was 0.26. After excluding data with acceleromyography-posttetanic counts over 15, 184 pairs of posttetanic counts were used to evaluate the agreement between the two monitoring methods. For acceleromyography-posttetanic count, 42 (23%) pairs had the same electromyography-posttetanic count, and 93 (50%) pairs had more than the electromyography-posttetanic count. The mean posttetanic count on electromyography was 38% (95% CI: 20% to 51%) lower than that on acceleromyography (P = 0.0002). Acceleromyography frequently counted more twitches than electromyography in posttetanic count monitoring. Acceleromyography- and electromyography-posttetanic counts cannot be used interchangeably to assess the degree of neuromuscular blockade.

Scaphotrapeziotrapezoid joint loading during key pinch grip before and after trapeziometacarpal arthroplasty: a cadaver study

In a previous cadaver study, we directly measured the load acting on the trapeziometacarpal joint for increasingly greater key pinch forces. We noted that the joint load ranges from 2 kg to 4 kg during progressively greater key pinch from 0.5 kg to 1.5 kg. Using the same experimental approach, the aim of the current study was to measure and compare the load acting on the scaphotrapeziotrapezoid joint for the same levels of isometric key pinch force, and how it changes after trapeziometacarpal arthroplasty. We performed a cadaver study using 7 fresh-frozen, unembalmed adult forearms and hands (2 right and 5 left). Thumb pinch was simulated by loading the main actuator tendons involved in the key pinch grip (i.e., adductor pollicis, flexor pollicis longus, extensor pollicis longus, extensor pollicis brevis and abductor pollicis longus tendons). Measurements were made inside the joint using a force-sensing resistor sensor (Tekscan® FlexiForce™ force sensor). Before the trapeziometacarpal joint surgery, median load values recorded in the scaphotrapeziotrapezoid joint were 1.2 kg (IQR, 1.0–1.4), 1.6 kg (IQR, 1.6–2.5) and 2.4 kg (IQR, 2.3–3.4) during 0.5 kg, 1 kg and 1.5 kg key pinch, respectively. After the trapeziometacarpal arthroplasty, median joint contact forces did not change significantly relative to the original configuration. Our findings indicate that the loads measured in the scaphotrapeziotrapezoid joint during a simple key pinch are in fact lower than those measured inside the trapeziometacarpal joint. After trapeziometacarpal arthroplasty, the values are similar with no increase in load, suggesting that clinically asymptomatic scaphotrapeziotrapezoid radiographic involvement may not be a contraindication to arthroplasty.