The relationship between sarcopenia and pain remains unclear; thus, this study evaluated whether muscle strength is independently associated with neuropathic-like pain symptoms in patients with chronic musculoskeletal pain. A cut-off score of painDETECT ≥13 was used to indicate a possible neuropathic component. Handgrip strength was measured, and muscle mass was estimated. A total of 2599 patients, including 439 patients who reported neuropathic-like pain symptoms (16.9%), were included for analysis. Handgrip strength was significantly lower in patients experiencing neuropathic-like pain symptoms (23.23 ± 10.57 vs. 24.82 ± 10.43 kg, p < 0.001), and this result was chiefly found in female patients. However, there was no difference in estimated muscle mass. Shorter duration of pain, opioid usage, pain in lower limbs, sleep disturbance, and lower handgrip strength were significantly associated with neuropathic-like pain symptoms. In patients with handgrip strength below the reference values by sex, experiencing radiating pain and at least moderate sensory symptoms by light touch and thermal stimulation were more frequently reported. In conclusion, lower handgrip strength appeared to be an independent factor associated with symptoms suggestive of neuropathic pain in this population. Interventional studies are required to determine whether improvement in muscle strength can reduce the neuropathic pain component in chronic musculoskeletal pain.

Purpose: Chronic low back pain is prevalent among older adults, who are at a higher risk for sarcopenia. The waist-to-calf circumference ratio has emerged as a health indicator, reflecting the balance between central adiposity and muscle mass. This study examined the association between waist-to-calf circumference ratio and sarcopenia, as well as factors like muscle mass, strength, and physical performance in older patients with chronic low back pain. Patients and Methods: Ambulatory patients aged 65 years and older with chronic low back pain were included. Sarcopenia was assessed using the 2019 diagnostic criteria from the Asian Working Group for Sarcopenia. We compared demographic data, pain-related factors, comorbidities, and measurements related to sarcopenia and obesity across quartiles of the waist-to-calf circumference ratio. The prevalence of sarcopenia and severe sarcopenia was investigated, and multivariable analysis was conducted to identify independent factors associated with sarcopenia. Results: Among 592 patients, 85 had sarcopenia (14.3%), and 71 had severe sarcopenia (11.9%). Patients with a high waist–calf circumference ratio had more comorbidities and longer pain duration. The prevalence of severe sarcopenia increased with higher quartile of waist–calf circumference ratio (Q1=7.9%, Q2=8.6%, Q3=14.8%, Q4=16.9%, P=0.006). When recommended cut-off values for the parameters used to diagnose sarcopenia were applied, the numbers of patients with low grip strength and low physical performance but not low muscle mass were greater among patients with a high waist–calf circumference ratio. Also, a high waist–calf circumference ratio was significantly associated with severe sarcopenia. Conclusion: In older patients with chronic low back pain, a high waist–calf circumference ratio was associated with severe sarcopenia, characterized by reduced muscle strength and impaired physical performance. The waist–calf circumference ratio might serve as a useful tool for assessing sarcopenia in this population.

Background: A precise anatomical understanding of the adductor canal (AC) and its neural components is essential for discerning the action mechanism of the AC block. We therefore aimed to clarify the detailed anatomy of the AC using micro-computed tomography (micro-CT), histological evaluation, and immunofluorescence (IF) assays.Methods: Gross dissections of 39 thighs provided morphometric data relevant to injection landmarks. Serial sectional images of the AC were defined using micro-CT and ultrasonography. The fascial and neural structures of the AC proper were histologically evaluated using Masson’s trichrome and Verhoeff-Van Gieson staining, and double IF staining using choline acetyltransferase (ChAT) and neurofilament 200 antibodies.Results: The posteromedial branch insertion of the nerve to vastus medialis (NVM) into the lateral border of the AC proper was lower (14.5 ± 2.4 cm [mean ± SD] above the base of the patella) than the origin of the proximal AC. The AC consists of a thin subsartorial fascia in the proximal region and a thick aponeurosis-like vastoadductor membrane in the distal region. In the proximal AC, the posteromedial branch of the NVM (pmNVM) consistently contained both sensory and motor fibers, and more ChAT-positive fibers were observed than in the saphenous nerve (27.5 ± 11.2 / 104 vs. 4.2 ± 2.6 / 104 [counts/µm2], P < 0.001).Conclusions: Anatomical differences in fascial structures between the proximal and distal AC and a mixed neural component of the neighboring pmNVM have been visualized using micro-CT images, histological evaluation, and IF assays.

Kim HJ, et al. Yonsei Med J. 2023 Jul;64(7):448-454. https://doi.org/10.3349/ymj.2023.0029

Background: Intraoperative pulmonary aspiration is a rare but potentially fatal complication associated with various risk factors. Preoperative recognition of these risk factors can prevent aspiration events during general anesthesia or facilitate prompt corrective measures in patients experiencing this complication. Case: A 70-year-old female patient with hypertension underwent bilateral total knee arthroplasty under general anesthesia. Despite using a midnight nothing-per-oral (NPO) protocol, an unpredictable intraoperative aspiration event occurred during anesthesia induction. A detailed evaluation of the patient’s medical history and subsequent diagnostic imaging examinations indicated achalasia. She was treated for aspiration pneumonia for 2 weeks. After 2 months, rescheduled total knee arthroplasty was performed under spinal anesthesia without any complications. Conclusions: Obtaining the patient’s medical history and assessing the risk factors are important to prevent unpredictable intraoperative pulmonary aspiration. High-risk patients should undergo adequate preoperative fasting and regional anesthesia or rapid-sequence intubation should be considered for safe induction of general anesthesia.