Pain Control and Satisfaction With Peripheral Nerve Blocks for Upper Extremity Surgery.

BACKGROUND: Regional anesthesia ("block") is an important component of upper extremity (UE) surgery pain control. However, little is known about patient experience related to perioperative opioid use. This study assessed patient-reported pain control and satisfaction with UE blocks and evaluated how opioid consumption impacted these outcomes before the block "wore off." METHODS: A postoperative phone survey was administered to patients who underwent outpatient UE surgery at a surgery center for more than 16 months. It assessed pain scores (scale 1-10), satisfaction with block duration (scale 1-5), duration until return of UE function, and opioid consumption. Analyses used Mann-Whitney U tests, Fisher exact tests, and bivariate and multivariable linear and ordered logistic regressions to understand relationships between opioid use and outcomes. RESULTS: A total of 509 patients (61%) completed the survey, and 441 (88%) were satisfied with block duration. Initial and final pain scores were significantly higher in patients who took opioids prior to the block wearing off (6 and 4.5, P = .04 and 3.5 and 2, P = .002, respectively). Although satisfaction with block duration was not different in group comparisons (ie, patients who premedicated vs those who did not), in a multivariable analysis, patients who premedicated with opioids had 78% increased odds of reporting the highest level of satisfaction compared with the lower 4 levels (P = .03). CONCLUSIONS: Upper extremity blocks are associated with high overall patient satisfaction and postsurgical pain control. Premedicating before the block wears off may increase patient satisfaction with block duration even if pain is not notably impacted.

Arterial Perfusion of the Proximal Phalanx Revisited: New Insights Based on Micro-Computed Tomography.

PURPOSE: To characterize the periosteal and endosteal arterial perfusion of the proximal phalanx using micro-computed tomography angiography (micro-CTA). METHODS: Cadaveric upper extremities were injected with a barium sulfate/gelatin suspension. Phalanges were imaged using micro-CTA and analyzed with a focus on osseous arterial anatomy. Periosteal and endosteal perfusion was characterized by number of vessels, length, anatomic course, and caliber. RESULTS: The base of the proximal phalanx had a significantly greater number (8.0 ± 3.5) of periosteal vessels than those of the shaft (4.1 ± 1.6) and head (1.3 ± 1.1). One-third (34.4%) of the specimens demonstrated a complete absence of periosteal vessels in the head. A nutrient endosteal vessel was noted in 100% of the specimens. Entering at the junction of the middle and distal third of the bone (25.8 ± 3.9 mm from base), the nutrient vessel entered the proximal phalanx of the index finger along its ulnar aspect (8 of 8 specimens), the middle finger along its radial aspect (6 of 8), the ring finger along its ulnar aspect (5 of 8), and the little finger along its radial aspect (7 of 8). The nutrient vessel branched into proximal and distal extensions toward the shaft and head, respectively, with an average endosteal length of 10.7 ± 5.2 mm and average diameter of 0.36 ± 0.11 mm. CONCLUSIONS: Periosteal contributions to the perfusion of the proximal phalanx appear to diminish distally. The endosteal arterial anatomy remains consistent, with a single nutrient vessel entering the intramedullary canal with reliable laterality on each digit. This is often the only vessel supplying the head of the proximal phalanx, making this area particularly susceptible to vascular compromise. CLINICAL RELEVANCE: An understanding of the patterns of perfusion of the proximal phalanx provides some insight into clinically observed pathology, as well as guidance for operative management.

Orthobiologics in Hand Surgery.

Orthobiologic agents are used as innovative adjuvant therapy to treat common upper-extremity pathology, including carpal tunnel syndrome, de Quervain tenosynovitis, and distal radius fractures. In this article, we perform a narrative review and evaluate current literature on orthobiologics in the upper extremity. Orthobiologics evaluated include bone morphogenetic proteins, platelet-rich plasma, bone marrow aspirate concentrate, mesenchymal stem cells, and amniotic membrane. Studies selected include randomized control trials, case studies, and animal studies. Although there is some clinical evidence regarding the use of orthobiologic agents in the treatment of shoulder, elbow, and sports injuries, there is a paucity of literature regarding their use to treat pathology of the hand and wrist. Further investigation is necessary to determine their effectiveness and therapeutic value in treatment of upper extremity injuries.

Stimulus Context and Reward Contingency Induce Behavioral Adaptation in a Rodent Tactile Detection Task.

Behavioral adaptation is a prerequisite for survival in a constantly changing sensory environment, but the underlying strategies and relevant variables driving adaptive behavior are not well understood. Many learning models and neural theories consider probabilistic computations as an efficient way to solve a variety of tasks, especially if uncertainty is involved. Although this suggests a possible role for probabilistic inference and expectation in adaptive behaviors, there is little if any evidence of this relationship experimentally. Here, we investigated adaptive behavior in the rat model by using a well controlled behavioral paradigm within a psychophysical framework to predict and quantify changes in performance of animals trained on a simple whisker-based detection task. The sensory environment of the task was changed by transforming the probabilistic distribution of whisker deflection amplitudes systematically while measuring the animal's detection performance and corresponding rate of accumulated reward. We show that the psychometric function deviates significantly and reversibly depending on the probabilistic distribution of stimuli. This change in performance relates to accumulating a constant reward count across trials, yet it is exempt from changes in reward volume. Our simple model of reward accumulation captures the observed change in psychometric sensitivity and predicts a strategy seeking to maintain reward expectation across trials in the face of the changing stimulus distribution. We conclude that rats are able maintain a constant payoff under changing sensory conditions by flexibly adjusting their behavioral strategy. Our findings suggest the existence of an internal probabilistic model that facilitates behavioral adaptation when sensory demands change.SIGNIFICANCE STATEMENT The strategy animals use to deal with a complex and ever-changing world is a key to understanding natural behavior. This study provides evidence that rodent behavioral performance is highly flexible in the face of a changing stimulus distribution, consistent with a strategy to maintain a desired accumulation of reward.