METHODS: Ninety-seven patients with adolescent idiopathic scoliosis (AIS) who underwent posterior spinal fusion surgery at a single tertiary institution from March 2019 until June 2020 were enrolled in this retrospective study. Anesthesia was maintained using a target-controlled infusion of remifentanil combined with volatile anesthetic desflurane in 92 patients, while five patients received it as part of total intravenous anesthesia. Intravenous ketamine, paracetamol, and fentanyl were administered as multimodal analgesia. All patients received patient-controlled analgesia (PCA) morphine postoperatively. Pain scores at rest and on movement, assessed using the numerical rating scale, and the cumulative PCA morphine consumption were collected at a six-hourly interval for up to 48 h. According to the median intraoperative remifentanil dose usage of 0.215 µg/kg/min, patients were divided into two groups: low dose and high dose group.
RESULTS: There were no significant differences in the pain score and cumulative PCA morphine consumption between the low and high dose remifentanil group. The mean duration of remifentanil infusion was 134.9 ± 22.0 and 123.4 ± 23.7 min, respectively.
CONCLUSION: Intraoperative use of remifentanil as an adjuvant in AIS patients undergoing posterior spinal fusion surgery was not associated with postoperative hyperalgesia.
SETTING: Hospital surgical ward.
SUBJECTS: Women (107 Indian, 184 Malay, and 750 Han Chinese) undergoing total hysterectomy surgery.
METHODS: Morphine consumption, preoperative pain, and postoperative pain were evaluated in relation to genetic variability comprising 19 single-nucleotide polymorphisms (SNPs) in 14 genes involved in glial activation, inflammatory signaling, and neuronal regulation, plus OPRM1 (1 SNP) and COMT (3 SNPs).
RESULTS: Pre- and postoperative pain and age were associated with increased and decreased morphine consumption, respectively. In Chinese patients, only 8% of the variability in consumption could be explained by these nongenetic and genetic (BDNF, IL1B, IL6R, CRP, OPRM1, COMT, MYD88) factors. However, in Indian patients, 41% of morphine consumption variability could be explained by age (explaining <3%) and variants in OPRM1 rs1799971, CRP rs2794521, TLR4 rs4986790, IL2 rs2069762, COMT rs4818, TGFB1 rs1800469, and IL6R rs8192284 without controlling for postoperative pain.
CONCLUSIONS: This is the highest known value reported for genetic contributions (38%) to morphine use in the acute postoperative pain setting. Our findings highlight the need to incorporate both genetic and nongenetic factors and consider ethnicity-dependent and nonadditive genotypic models in the assessment of factors that contribute to variability in opioid use.
METHODS: Patients (n = 94) scheduled for gynaecological laparotomy received i.v. fentanyl infusion (3 μg/kg/h) after induction of general anaesthesia. Post-operative fentanyl requirements were quantified by using a patient-controlled analgesia and the number of i.v. fentanyl rescue analgesia required were recorded. Pain control was assessed using visual analogue scores (VAS) and fentanyl's adverse effects were documented. CYP3A4*4, CYP3A4*5 and CYP3A4*18 alleles of cytochrome P450 3A4 were identified by polymerase chain reaction-restriction fragment length polymorphism. Differences in fentanyl requirements, VAS scores and adverse effects among the various genotypes were compared.
RESULTS AND DISCUSSION: No CYP3A4*4 and CYP3A4*5 alleles were detected. Eighty-nine patients (94·7%) were wild-type, five (5·3%) were heterozygous and none was homozygous. No significant difference was demonstrated between the genotype groups in terms of fentanyl consumption, pain control and adverse effects.
WHAT IS NEW AND CONCLUSION: CYP3A4*4 and CYP3A4*5 are rare in the Malaysian Malay population. Genetic polymorphism of CYP3A4*18 may not play an important role in influencing postoperative fentanyl requirements.
OBJECTIVE: The aim of this study was to determine and evaluate the trajectory of surgical wound pain from day 1 to day 14 after posterior spinal fusion (PSF) surgery in patients with adolescent idiopathic scoliosis (AIS).
SUMMARY OF BACKGROUND DATA: Information regarding how the postoperative pain improves with time offers invaluable information not only to the patients and parents but also to assist the clinician in managing postoperative pain.
METHODS: AIS patients who were planned for elective PSF surgery from September 2015 to December 2015 were prospectively recruited into this study. All patients underwent a similar pain management regimen with patient-controlled anesthesia (PCA) morphine, acetaminophen, celecoxib, and oxycodone hydrochloride.
RESULTS: A total of 40 patients (36 F:4 M) were recruited. The visual analogue score (VAS) pain score was highest at 12 hours postoperation (6.0 ± 2.3). It reduced to 3.9 ± 2.2 (day 4), 1.9 ± 1.6 (day 7), and 0.7 ± 1.1 (day 14). The total PCA usage in all patients was 12.4 ± 9.9 mg (first 12 hours), 7.1 ± 8.0 mg (12 to 24 hours), 5.6 ± 6.9 (24-36 hours), and 2.1 ± 6.1 mg (36-48 hours). The celecoxib capsules usage was reducing from 215.0 ± 152.8 mg at 24 hours to 55.0 ± 90.4 mg on day 14. The acetaminophen usage was reducing from 2275 ± 1198 mg at 24 hours to 150 ± 483 mg at day 14. Oxycodone hydrochloride capsules consumption rose to the peak of 1.4 ± 2.8 mg on day 4 before gradually reducing to none by day 13.
CONCLUSION: With an adequate postoperation pain regimen, significant pain should subside to a tolerable level by postoperative day 4 and negligible by postoperative day 7. Patient usually can be discharged on postoperative day 4 when the usage of PCA morphine was not required.
LEVEL OF EVIDENCE: 2.