Chronic post-thyroidectomy pain: Incidence, typology, and risk factors

Transitional Pain Medicine; New Era, New Opportunities, and New Journey

Chronic postsurgical pain (CPSP), also known as persistent postsurgical pain (PPSP), is pain that develops or increases in intensity after a surgical procedure and lasts more than 3 months. Transitional pain medicine is the medical field that focuses on understanding the mechanisms of CPSP and defining risk factors and developing preventive treatments. Unfortunately, one significant challenge is the risk of developing opioid use dependence. Multiple risk factors have been discovered, with the most common, and modifiable, being uncontrolled acute postoperative pain; preoperative anxiety and depression; and preoperative site pain, chronic pain, and opioid use.

Comparison of the effects of sevoflurane and desflurane on the severity score of postoperative pain and discomfort after thyroidectomy: A prospective, double-blinded, randomized controlled study

BACKGROUND

Thyroidectomy is performed under general anesthesia using inhaled anesthetics such as sevoflurane or desflurane in many cases. The objective of this study was to investigate whether the incidence of postoperative pain and discomfort after thyroidectomy differed with the type of inhaled anesthetic.

METHODS

Eighty-one female patients who underwent thyroidectomy were randomly assigned to the Sevo group (n = 42) or the Des group (n = 39). On the day of surgery and on the first, third, and seventh days after surgery, one registered nurse in charge of the entire questionnaire survey conducted the questionnaire assessment through face-to-face interviews or phone calls with the patients. The questionnaire evaluated the severity scores for seven items (sore throat, wound pain, nausea and vomiting, dizziness, occipital headache, posterior neck pain, and shoulder pain) regarding postoperative pain and discomfort experienced by patients and assessed which of these seven items caused the greatest discomfort to the patient on each day.

RESULTS

Except for the severity score for dizziness on the day of surgery, the severity scores of postoperative pain and discomfort experienced by patients on the day of surgery and on the first, third, and seventh days after surgery showed no statistically significant differences between the two groups. In addition, on the day of surgery and on the first, third, and seventh days after surgery, patients reported that sore throat caused the greatest discomfort.

CONCLUSION

In patients undergoing thyroidectomy under general anesthesia using sevoflurane or desflurane, except for dizziness on the day of surgery, no other manifestation of postoperative pain and discomfort was influenced by the type of inhaled anesthetic. Moreover, after thyroidectomy, postoperative sore throat caused the greatest discomfort to patients from the day of surgery to the seventh day after surgery.

Electroacupuncture relieves hyperalgesia by regulating neuronal–glial interaction and glutamate transporters of spinal dorsal horns in rats with acute incisional neck pain

Objective

Glial cells are involved in the analgesic effect of electroacupuncture (EA) in rats with chronic neurological pain. The objective of this study was to observe the role of neuronal–glial interaction and glutamate (Glu) transporters in EA-induced acute neck pain relief in rats.

Materials and methods

Male rats were placed into the following five groups: control, model, EA Futu (LI18), EA Hegu (LI4)-Neiguan (PC6), and EA Zusanli (ST36)-Yanglingquan (GB34). The incisional neck pain model was established by making a longitudinal incision along the midline of the neck. The thermal pain threshold (TPT) was measured using a radiation heat detector. The immunoactivities of glial fibrillary acidic protein (GFAP), ionized calcium-binding adapter molecule 1 (Iba-1), neurokinin-1 receptor (NK-1R), Glu aspartate transporter (GLAST), and Glu transporter-1 (GLT-1) in the dorsal horns (DHs) of the cervico-spinal cord (C2–C5) were detected using immunofluorescence histochemistry. The expression levels of GFAP, Iba-1, GLAST, and GLT-1 mRNAs were determined using quantitative real-time polymerase chain reaction (PCR).

Results

The TPT and levels of mRNAs expression and immunoactivity of GLT-1 and GLAST were significantly decreased, and those of Iba-1 and GFAP were significantly increased in the model group than those of the control group (P < 0.05). The activated microgliacytes were gathered around the NK-1R positive neurons, and co-expression of NK-1R and astrocytes was observed in the model group. EA LI18 significantly increased the TPT and expression of GLAST and GLT-1 mRNAs (P < 0.05) and notably decreased the number of Iba-1 positive cells and Iba-l mRNA expression (P < 0.05), whereas GLAST and GLT-1 antagonists inhibited the analgesic effect of EA LI18. However, these effects, except for the downregulation of Iba-1 mRNA, were not observed in the EA ST36-GB34 group. Fewer NK-1R-positive neurons were visible in the spinal DHs in the EA LI18 group, and the co-expression of NK-1R and astrocytes was also lower than that in the three EA groups.

Conclusion

Electroacupuncture of LI18 had an analgesic effect in rats with neck incisions, which may be related to its functions in suppressing the neuronal–glial cell interaction through NK-1R and upregulating the expression of GLAST and GLT-1 in the spinal DHs.

Analgesic effect of paracetamol monotherapy vs. the combination of paracetamol/parecoxib vs. the combination of pethidine/paracetamol in patients undergoing thyroidectomy

INTRODUCTION

The purpose of this study was to investigate the analgesic effect of 3 different regimens of combination analgesics administered to patients undergoing thyroidectomy.

MATERIAL AND METHODS

A total of 152 patients undergoing total or subtotal thyroidectomy were enrolled. Patients allocated to group A received a combination of intravenous (IV) paracetamol and intramuscular (IM) pethidine, patients in group B received a combination of IV paracetamol and IV parecoxib, while patients in group C received IV paracetamol monotherapy.

RESULTS

The analgesic regimens of groups A and B were found to be of equivalent efficacy (p-value = 1.000). In contrast, patients in group C (paracetamol monotherapy) had higher numerical rating scale scores, compared to both patients in groups A (p-value < 0.001) and B (p-value < 0.001).

CONCLUSIONS

The combinations of IV paracetamol with either IM pethidine or IV parecoxib are superior to IV paracetamol monotherapy in achieving pain control in patients undergoing thyroid surgery.

The analgesic efficacy of bilateral superficial cervical plexus block for thyroid surgery under general anesthesia: a prospective cohort study

Objective

Uses of simple analgesics were found insufficient to manage pain after thyroid surgery. We hypothesized that using bilateral superficial cervical plexus block (BSCPB) might influence the pattern of immediate postoperative pain and analgesic consumption. The general objective of the study was to assess the analgesic efficacy of bilateral superficial plexus block for thyroid surgery under general anesthesia.

Results

A total of 74 willing patients involved. Half of them had received BSCPB with 10 ml of 0.25% bupivacaine just before induction and the remaining half did not. Postoperatively, patients were assessed at immediate, 2nd, 6th, 12th and 24th h. At all endpoints, NRS-11 scores for pain were significantly lower in the block group. The time to first analgesic requirement was significantly longer 132.3 ± 71.5 min vs 71.4 ± 60.0 min, p = 0.009. Opioid and total analgesic consumption were reduced by BSCPB in the first 24 postoperative hours. There was low but non-significant rate of PONV in the block group. No clinically important adverse event was noted related to BSCPB.

Trial registration The study was registered in Pan African Clinical Trial Registry on 13/01/2020 and the registration number is PACTR202001579588451. Retrospectively registered.

Chronic postoperative pain: recent findings in understanding and management

Chronic postoperative pain is a poorly recognized potential outcome from surgery. It affects millions of patients every year, with pain lasting for months to years, resulting in patient suffering and ensuing economic consequences. The operations with the highest incidence of chronic postoperative pain are amputations, thoracotomies, cardiac surgery, and breast surgery. Other risk factors include preoperative pain, psychological factors, demographics, and the intensity of acute postoperative pain. Attempts to prevent chronic postoperative pain have often led to debatable results. This article presents data from recently published studies examining the incidence, risk factors, mechanisms, treatment options, and preventive strategies for chronic postoperative pain in adults. In summary, many of the previously identified risk factors for chronic postoperative pain have been confirmed and some novel ones discovered, such as the importance of the trajectory of acute pain and the fact that catastrophizing may not always be predictive. The incidence of chronic postoperative pain hasn’t changed over time, and there is limited new information regarding an effective preventive therapy. For example, pregabalin may actually cause more harm in certain surgeries. Further research is needed to demonstrate whether multimodal analgesic techniques have the best chance of significantly reducing the incidence of chronic postoperative pain and to determine which combination of agents is best for given surgical types and different patient populations.