Opioids in the management of persistent non-cancer pain

The medical use of opioids to treat pain and illness predates historic record. Opioids have a well-defined role in the treatment of acute and cancer pain, and most clinicians are comfortable prescribing opioids in these contexts. However, in persistent non-cancer pain (PNCP) there remains considerable controversy. While there is evidence of short-to-medium-term benefit, concerns exist over long-term efficacy, side effects, safety, and the potential for opioid misuse. Guidelines published to date emphasize the importance of patient selection, opioid preparation, monitoring of therapy, and a multimodal treatment package including other disciplines and non-pharmacological therapies. Worldwide, the use of opioids for PNCP has increased significantly over the past decade and with it, concerns of increases in opioid-related harm.     

Chronic Use of Opioids Before and After Total Knee Arthroplasty: A Retrospective Cohort Study

Background

Opioids are commonly used for the management of preoperative and postoperative pain among patients undergoing total knee arthroplasty (TKA). There is limited literature on the chronic use of opioids pre-TKA and post-TKA. The aim of this study was to characterize the use of opioids in TKA patients before and after surgery and identify risk factors of chronic opioid use.

Breakthrough pain in opioid-treated chronic non-malignant pain patients referred to a multidisciplinary pain centre: a preliminary study

BACKGROUND: Breakthrough pain (BTP) has not formerly been discussed as such in chronic non-malignant pain patients referred to pain centres and clinics. The purpose of the study was to investigate the prevalence, characteristics and mechanisms of BTP in opioid-treated chronic non-malignant pain patients referred to a pain centre and to assess the short-term effects of pain treatment. METHODS: Patients were assessed at referral (T(0)) and after a treatment period of 3 months (T(3)) using the visual analogue scale (VAS) of the brief pain inventory (BPI) within somatic nociceptive, neuropathic and/or visceral pain conditions, the mini mental state examination (MMSE) and the hospital anxiety and depression scale (HADS). The main treatment intervention from T(0) to T(3) was to convert short-acting oral opioids to long-acting oral opioids and to discontinue on demand and parenteral use of opioids. RESULTS: Thirty-three patients were assessed at T(0) and 27 at T(3). The prevalence of BTP declined significantly from T(0) (90%) to T(3) (70.4%). Worst, least, average and current pain intensities as well as duration of BTP were significantly reduced from T(0) to T(3.) The majority of BTPs were exacerbation of background pain assumed to be of the same pain mechanisms. High average pain intensity (BPI) was significantly associated with high scores for both anxiety and depression (HADS). CONCLUSION: BTP in chronic non-malignant pain patients seems to be surprisingly frequent and severe. Stabilizing the opioid regimen seems to reduce pain intensity in general as well as the intensity and duration of BTP. Average pain intensity was associated with anxiety and depression.     

Sleep disturbance in patients taking opioid medication for chronic back pain

Poor sleep is an increasingly recognised problem with chronic pain and further increases the effect on daily function. To identify the relationship between chronic pain, opioid analgesia and sleep quality, this study investigated activity and sleep patterns in patients taking opioid and non‐opioid analgesia for chronic back pain. Thirty‐one participants (10 healthy controls, 21 patients with chronic pain: 6 on non‐opioid medication; 15 on opioid medication) were assessed using actigraphy, polysomnography and questionnaires. Patients with chronic pain subjectively reported significant sleep and wake disturbances as shown by decreased overall sleep quality (Pittsburgh Sleep Quality Index, p < 0.001), increased symptoms of insomnia (Insomnia Severity Index, p < 0.001) and increased fatigue (Fatigue Severity Scale, p = 0.002). They also spent increased time in bed (p = 0.016), took longer to get to sleep (p = 0.005) and had high interindividual variability in other measures of activity but no overall irregular rest‐activity pattern. Patients on high doses of opioids (> 100 mg morphine‐equivalent/day) demonstrated distinctly abnormal brain activity during sleep suggesting that polysomnography is necessary to detect sleep disturbance in this population in the absence of irregular rest‐activity behaviour. Night‐time sleep disturbance is common in individuals suffering from chronic pain and may be further exacerbated by opioid treatment. Considerations must be made regarding the appropriate use of combined actigraphy and miniaturised polysomnography for future population‐based studies.     

Chronic pain after surgery

Br J Anaesth 2001; 87: 88–98     

Clinical experience of long–term treatment with epidural and intrathecal opioids – a nationwide survey

Long–term use of spinal opioids to treat chronic severe pain is widely established. However, the indications, shortcomings and complications of the method have not been completely described. Experience with spinal opioids was analysed for the period 1979–1984 in a nationwide Swedish survey. Out of 93 anaesthesia departments, 69 used the method. Approximately 750 patients were treated with epidural morphine for an average duration of 124 days (3–450). Eighteen patients were treated with intrathecal morphine for an average period for 47 days (3–90). The intrathecal approach was used in all clinics because of failure of the epidural route. In only one department was the intrathecal approach used as the primary route of therapy, depending on the mechanism of pain. The highest daily morphine dose was 480 mg and 50 mg for epidural and intrathecal routes, respectively. The patients given the highest dosages were not necessarily those subjected to the longest treatment. The need for increased dosage seems to be related not only to changes in receptor sensitivity but also to changes in pain mechanisms. No case of threatening ventilatory depression was reported. Thirty–two departments had treated a few patients with chronic non–cancer pain conditions. Initial results were considered "excellent" in H departments, but at follow–up results were excellent in only one department. In addition to dislocation, occlusion of the catheters or leakage, injection pain was an obstacle to successful treatment. Pruritus, urinary retention, and local infections were not reported as significant problems, but one case of meningitis was reported.     

Caring for patients with pain during the COVID-19 pandemic: consensus recommendations from an international expert panel

Chronic pain causes significant suffering, limitation of daily activities and reduced quality of life. Infection from COVID-19 is responsible for an ongoing pandemic that causes severe acute respiratory syndrome, leading to systemic complications and death. Led by the World Health Organization, healthcare systems across the world are engaged in limiting the spread of infection. As a result, all elective surgical procedures, outpatient procedures and patient visits, including pain management services, have been postponed or cancelled. This has affected the care of chronic pain patients. Most are elderly with multiple comorbidities, which puts them at risk of COVID-19 infection. Important considerations that need to be recognised during this pandemic for chronic pain patients include: ensuring continuity of care and pain medications, especially opioids; use of telemedicine; maintaining biopsychosocial management; use of anti-inflammatory drugs; use of steroids; and prioritising necessary procedural visits. There are no guidelines to inform physicians and healthcare providers engaged in caring for patients with pain during this period of crisis. We assembled an expert panel of pain physicians, psychologists and researchers from North America and Europe to formulate recommendations to guide practice. As the COVID-19 situation continues to evolve rapidly, these recommendations are based on the best available evidence and expert opinion at this present time and may need adapting to local workplace policies.     

The advantages of intrathecal opioids for spinal fusion in children

Two groups of 40 homogeneous patients (ASA physical status (1–2)) with idiopathic scoliosis undergoing spinal fusion with CD instrumentation were studied prospectively. Group A (intrathecal) received a mixture of morphine and sufentanil administered intrathecally at the level of L3–L4 after the induction of anaesthesia. Group B (control) had inhalation and intravenous narcotic anaesthesia. The use of intrathecal opioids resulted in a significant reduction of blood pressure without the use of any hypotensive agents and produced prolonged postoperative analgesia. There was no adverse effect on somatosensory evoked potentials. The dose requirement for the anaesthetic agents was significantly reduced and the blood loss was 27% of their blood volume compared with 53% in the control group. No long or short term impairment of cerebral or spinal function was observed. The use of intrathecal opioids supplemented with other anaesthetic agents is an alternative method with multiple benefits for any major surgery such as spinal fusion.     

Causes,prevention, and surgical treatment of postherniorrhaphy neuropathic inguinodynia: Triple neurectomy with proximal end implantation

The recommended surgical treatment for chronic neuropathic pain after herniorrhaphy has been a two-stage operation including: (a) ilioinguinal and iliohypogastric neurectomies through an inguinal approach and (b) genital nerve neurectomy through a flank approach. Two hundred twenty-five patients underwent triple neurectomies with proximal end implantation to treat chronic postherniorrhaphy neuralgia. Four patients reported no improvement. Eighty percent of patients recovered completely, and 15% had transient insignificant pain with no functional impairment. These results are comparable to the results of the two-stage operation. Simultaneous neurectomy of the ilioinguinal, iliohypogastric, and genital nerves without mobilization of the spermatic cord is an effective one-stage procedure to treat postherniorrhaphy neuralgia. It can be performed under local anesthesia and avoids testicular complications. Proximal end implantation of the nerves prevents adherence of the cut ends to the aponeurotic structures of the groin, which can result in recurrence of the pain. A one-stage surgical procedure resecting all three nerves from an anterior approach avoids a second operation through the flank and successfully treats chronic neuralgia.This paper was presented at the meeting of the American Hernia Society in Orlando, Fla. USA, on February 2004     

Cancer pain management

Pain occurs in more than 80% of cancer patients before death. Because of the increase in the frequency of cancer deaths worldwide, it is imperative to address cancer pain as a public health problem. Until recently, educational efforts were focused on treatment issues rather than adequate assessment. The approach to pain intensity as a multidimensional construct has helped in focusing treatments and identifying prognostic factors. Valid tools have been developed that allow multidisciplinary assessment of these prognostic factors and their complex interrelationship with the analgesic response. As a result of increased opioid exposure, patients are currently developing newer toxicities, mostly central excitability including delirium, myoclonus, grand mal seizures, and hyperalgesia. The observation that more than 80% of patients will require alternate routes for opioid delivery before death led to the development of a number of novel and effective alternate routes for delivery. Finally, in recent years it has become evident that some specific pain syndromes need to be addressed using specific assessment and management techniques. Incidental pain, somatization, neuropathic pain, and cancer pain in patients with alcoholism and drug addiction are some of these syndromes.     

Age- and therapy-related effects on morphine requirements and plasma concentrations of morphine and its metabolites in postoperative infants

Background. To investigate clinical variables such as gestationalage, sex, weight, the therapeutic regimens used and mechanicalventilation that might affect morphine requirements and plasmaconcentrations of morphine and its metabolites. Methods. In a double-blind study, neonates and infants stratifiedfor age [group I 0–4 weeks (neonates), group II