The value of pupillary diameter in evaluating pain perception after awakening in patients undergoing general anesthesia during orthopedic surgery.

BACKGROUND: The pupillary response to tetanic electrical stimulation reflects the balance between nociceptive stimulation and analgesia. Although pupillary pain index (PPI) was utilized to predict postoperative pain, it depended on tetanic stimulation and was complex. We aim to describe the potential relationship between PD in the presence of surgical stimulation and pain levels after awakening. METHODS: According to the Verbal Rating Scale (VRS) score after extubation, the patients were divided into painless group (VRS = 0) and pain group (VRS ≥ 1). Pupillary diameter (PD) and pupillary light reflex velocity (PLRV) were compared between two groups when patients entered the operating room (T1), before incision (T2), 10 s after incision (T3), 30 s after incision (T4), 1 h after incision (T5), at the end of surgery (T6), shortly after extubation (T7), and when patients expressed pain clearly (T8). The magnitude of PD change (ΔPD) compared to the baseline value after anesthesia induction (T2) was calculated. The correlations between pupillary parameters and pain after awakening were calculated. RESULTS: Patients with VRS ≥ 1 had greater PD than painless patients at T3-7 (P = 0.04, 0.04, 0.003, <0.001, <0.001), and it was positively correlated with VRS score after awakening at T4-7 (r = 0.188, 0.217, 0.684, 0.721). The ability of T6ΔPD to predict VRS ≥ 1 was strong [threshold: 20.53%, area under the curve (AUC): 0.93, 95% confidence interval (CI): 0.89-0.97 ]. CONCLUSION: Our study indicates that PD is a useful index to direct the individualized analgesics used during operation, to better avoid the occurrence of pain during the postoperative emergence period. TRIAL REGISTRATION: This study was registered with the Chinese Clinical Trial Registry (registration number: ChiCTR2000040908, registration date: 15/12/2020).

The role of ectopic P granules protein 5 homolog (EPG5) in DHPG-induced pain sensitization in mice.

Nociplastic pain is a severe health problem, while its mechanisms are still unclear. (R, S)-3,5-Dihydroxyphenylglycine (DHPG) is a group I metabotropic glutamate receptor (mGluR) agonist that can cause central sensitization, which plays a role in nociplastic pain. In this study, after intrathecal injection of 25 nmol DHPG for three consecutive days, whole proteins were extracted from the L4~6 lumbar spinal cord of mice 2 h after intrathecal administration on the third day for proteomics analysis. Based on the results, 15 down-regulated and 20 up-regulated proteins were identified in mice. Real-time quantitative PCR (RT-qPCR) and western blotting (WB) revealed that the expression of ectopic P granules protein 5 homolog (EPG5) mRNA and protein were significantly up-regulated compared with the control group, which was consistent with the proteomics results. Originally identified in the genetic screening of Caenorhabditis elegans, EPG5 is mainly involved in regulating autophagy in the body, and in our study, it was mainly expressed in spinal neurons, as revealed by immunohistochemistry staining. After the intrathecal injection of 8 µL adeno-associated virus (AAV)-EPG5 short hairpin RNA (shRNA) to knock down spinal EPG5, the hyperalgesia caused by DHPG was relieved. Altogether, these results suggest that EPG5 plays an important role in DHPG-induced pain sensitization in mice.

Role of fragile X mental retardation protein in chronic pain.

Chronic pain has detrimental effects on one's quality of life. However, its treatment options are very limited, and its underlying pathogenesis remains unclear. Recent research has suggested that fragile X mental retardation protein is involved in the development of chronic pain, making it a potential target for prevention and treatment. The current review of literature will examine the function of fragile X mental retardation protein and its associated pathways, through which we hope to gain insight into how fragile X mental retardation protein may contribute to nociceptive sensitization and chronic pain.

A case of synchronous breast and bilateral lung cancers: literature review and considerations for radiation treatment planning.

Limited literature is available regarding treatment strategies for three concurrent potentially curable malignancies, and only one case of primary breast cancer with bilateral primary lung cancers has been reported. There is no literature available on approaches to radiation treatment planning and delivery in this challenging scenario. We report a case of a 66-year-old female who underwent partial mastectomy and sentinel node biopsy for left-sided breast cancer, pT1cN1(mic). Metastatic work-up revealed bilateral primary lung cancers, biopsy-proven, each Stage cT1N0. Distinguishing synchronous primary tumours from metastatic disease can be challenging. The histological examination suggested three distinct primaries and each was potentially curable. Devising a treatment strategy required balancing the incremental benefits with the toxicity of combining each of the treatments. Stereotactic ablative radiotherapy was the treatment of choice for the patient's lung primaries, as she was deemed a high-risk surgical candidate. Tangential whole breast radiotherapy with regional nodal irradiation was deemed appropriate for her breast cancer. Treatment for all three sites was planned concurrently, taking into account any potential overlap of dose in the composite plan. Each lung lesion was treated with 48 Gy in 4 fractions with stereotactic ablative radiotherapy using volumetric modulated arc therapy technique. The breast and supraclavicular regions were treated with 50 Gy in 25 daily fractions using a field-in-field technique. Optimal clinical outcomes for patients with multiple primary cancers require optimal definitive management. In this unique case of triple primaries, curative-intent radiotherapy to both lungs, the left breast and regional nodes was planned to be given concurrently and treatment was successfully delivered without significant toxicity.

On the use of the MLC dosimetric leaf gap as a quality control tool for accurate dynamic IMRT delivery.

PURPOSE: MLC leaf gap consistency is critical for the accurate delivery of dynamic IMRT plans. It is estimated that a systematic MLC leaf gap change of 0.6 mm will result in a 2% change to the equivalent uniform dose to a clinical target volume for a typical head and neck sliding window (SW) IMRT plan. The aim of this work is to use the measured dosimetric leaf gap (DLG) to verify the dosimetric reproducibility of dynamically delivered SW IMRT plans. This study focuses on Varian linacs equipped with the 120 Millennium MLC and the Eclipse treatment planning system (TPS), but can be extended to other linac/MLC/TPS combination. METHODS: An ionization chamber, a diode array, and an electronic portal imaging device (EPID) were used to assess the DLG in zero (central axis), one, and two dimensions, respectively. The DLG for zero and two dimensions was derived from measurements of SW fields of decreasing width (2, 1.5, 1, and 0.5 cm). The DLG in one dimension was measured directly from a single SW sweeping across a linear diode array. This one-dimensional DLG measurement was based on the full width at half maximum (FWHM) of the dose rate versus time spectrum. RESULTS: The DLG derived from ion chamber measurements at central axis agrees to within 0.1 mm, with the DLG measured directly from the FWHM of dose rate versus time spectrum. The measured DLG depends on the control points used for the MLC SW fields. When two control points were used, the DLG measured at central axis showed an increase of 0.6 mm with respect to the same measurements performed using three or more control points. The two-dimensional distribution of DLG obtained using the EPID identified leaf gap errors as small as +/- 0.2 mm in isolated areas away from central axis. CONCLUSIONS: Comprehensive measurements of the DLG in 0D, 1D, and 2D provide an accurate assessment of DLG value required during TPS commissioning. These DLG measurements can also be used as a quality control tool to quantify changes of the MLC calibration and leaf gap consistency, which is critical for the accurate delivery of dynamically delivered SW IMRT plans.