A review of the literature on multiple factors involved in postoperative pain course and duration

Chronic continuous abdominal pain: evaluation of diagnostic features, iatrogenesis and drug treatments in a cohort of 103 patients

BACKGROUND

Chronic continuous abdominal pain (CCAP) is characteristic of centrally mediated gastrointestinal pain disorders. It consumes significant healthcare resources yet is poorly understood, with minimal cohort-specific data in the literature.

AIMS

To examine in a large cohort of CCAP patients, (a) diagnostic features, (b) iatrogenic impact of opioids and surgery, (c) drug treatment effects and tolerance.

METHODS

Consecutive tertiary CCAP referrals to a neurogastroenterology clinic (2009-2016) were reviewed for Rome IV and neuropathic pain criteria. Medical, surgical and drug histories, interventions and outcomes were correlated with clinical diagnosis and associated opioid use.

RESULTS

Of 103 CCAP patients (mean age 40 ± 14, 85% female), 50% had physiological exacerbations precluding full Rome IV Centrally Mediated Abdominal Pain Syndrome criteria. However, there were no significant differences between patients who satisfied Rome IV criteria and those who did not. Overall, 81% had allodynia (a nonpainful stimulus evoking pain sensation). Opioid use was associated with allodynia (P = 0.003). Prior surgery was associated with further operations post CCAP onset (P < 0.001). Although 68% had undergone surgical interventions, surgery did not resolve pain in any patient and worsened pain in 35%. Whilst duloxetine was the most effective neuromodulator (P = 0.003), combination therapy was superior to monotherapy (P = 0.007).

CONCLUSIONS

This is currently the largest cohort CCAP dataset that supports eliciting neuropathic features, including allodynia, for a positive clinical diagnosis, to guide treatment. Physiological exacerbation of CCAP may represent visceral allodynia, and need not preclude central origin. Use of centrally acting neuromodulators, and avoidance of detrimental opioids and surgical interventions appear to predict favourable outcomes.

Membrane protein Nav1.7 contributes to the persistent post-surgical pain regulated by p-p65 in dorsal root ganglion (DRG) of SMIR rats model

Background

Persistent post-surgical pain is a difficult clinical problem. In this study, we intend to explore the mechanism underlying the persistent post-surgical pain in SMIR (skin/muscle incision and retraction) rats.

Methods

First of all, the expression of membrane protein Nav1.7 and p-p65 (Phosphorylation of p65) were detected in ipsilateral L4–6 DRGs of SMIR rats by western-blot and immunostaining. Then with ProTx-II (Nav1.7 blocker) or PDTC (p65 inhibitor) were intrathecally injected while the change of Nav1.7 expression and mechanical withdrawal threshold were detected. Finally chromatin immunoprecipitation assay method was used to detect whether could p-p65 bind in the Nav1.7 gene promoter region directly.

Results

The results shows that mechanical hyperalgesia occurs following SMIR model, from 5 day (d) and lasted more than 20d after surgery. Meanwhile, the expression of Nav1.7 was up-regulated at 10d, 15d and 20d after surgery compared with naïve group. The expression of p-p65 was up-regulated at 10d and 15d compared with incision group. The mechanical hyperalgesia induced by SMIR was reversed after blocking Nav1.7 or inhibiting p65. Furthermore, Nav1.7 expression was down-regulated when p-p65 was inhibited and p-p65 could combine with the Nav1.7 gene promoter region directly.

Conclusion

Membrane protein Nav1.7 could participate in the peripheral sensitization of persistent post-surgical pain, which may be regulated by p-p65.

Factors affecting postoperative pain and delay in discharge from the post-anaesthesia care unit: A descriptive correlational study

Background:

Pain occurring in the post-anaesthesia care unit (PACU) is common, distressing to patients and remains a management challenge for staff. This study aims to identify the factors affecting pain severity and delay in discharge of patients from the PACU.

Methods:

Data from 590 consecutive postoperative patients in the PACU was collected over one month in 2012 at the Singapore General Hospital. Patient demographics, surgical, intraoperative anaesthetic and recovery data were collected. The primary outcome measured was postoperative pain score and secondary outcome was a delay in discharge. Univariate and multivariate logistic regression were performed to determine preoperative and intraoperative variables that may be associated with pain and delayed discharge.

Results:

The majority (67.6%) of patients reported no to mild pain while 32.3% reported moderate to severe pain; 65.4% of patients had delayed discharge and 28.3% of these were a result of uncontrolled pain. Factors associated with moderate to severe postoperative pain included younger age, same day admissions, duration of operation >2 h, abdominal, upper limb and spine surgeries and use of general anaesthesia. Factors associated with delay in discharge included higher body mass index, abdominal, spine and superficial surgeries, use of general anaesthesia, moderate to severe pain score and use of nurse controlled analgesia.

Conclusions:

This study identifies predictive factors for postoperative pain and delay in discharge from the PACU. Knowledge of these factors may help in better clinical judgment for postoperative pain management and can lead to quality improvement measures for patient management and work flow in the PACU.

Minimally invasive surgery of the anterior skull base: transorbital approaches

Minimally invasive approaches are becoming increasingly popular to access the anterior skull base. With interdisciplinary cooperation, in particular endonasal endoscopic approaches have seen an impressive expansion of indications over the past decades. The more recently described transorbital approaches represent minimally invasive alternatives with a differing spectrum of access corridors. The purpose of the present paper is to discuss transorbital approaches to the anterior skull base in the light of the current literature. The transorbital approaches allow excellent exposure of areas that are difficult to reach like the anterior and posterior wall of the frontal sinus; working angles may be more favorable and the paranasal sinus system can be preserved while exposing the skull base. Because of their minimal morbidity and the cosmetically excellent results, the transorbital approaches represent an important addition to established endonasal endoscopic and open approaches to the anterior skull base. Their execution requires an interdisciplinary team approach.

Correlation of Uptake Patterns on Single-Photon Emission Computed Tomography/Computed Tomography (SPECT/CT) and Treatment Response in Patients with Knee Pain

PURPOSE

To determine whether treatment response in patients with knee pain could be predicted using uptake patterns on single-photon emission computed tomography/computed tomography (SPECT/CT) images.

METHODS

Ninety-five patients with knee pain who had undergone SPECT/CT were included in this retrospective study. Subjects were divided into three groups: increased focal uptake (FTU), increased irregular tracer uptake (ITU), and no tracer uptake (NTU). A numeric rating scale (NRS-11) assessed pain intensity. We analyzed the association between uptake patterns and treatment response using Pearson's chi-square test and Fisher's exact test. Uptake was quantified from SPECT/CT with region of interest (ROI) counting, and an intraclass correlation coefficient (ICC) calculated agreement. We used Student's t-test to calculate statistically significant differences of counts between groups and the Pearson correlation to measure the relationship between counts and initial NRS-1k1. Multivariate logistic regression analysis determined which variables were significantly associated with uptake.

RESULTS

The FTU group included 32 patients; ITU, 39; and NTU, 24. With conservative management, 64 % of patients with increased tracer uptake (TU, both focal and irregular) and 36 % with NTU showed positive response. Conservative treatment response of FTU was better than NTU, but did not differ from that of ITU. Conservative treatment response of TU was significantly different from that of NTU (OR 3.1; p = 0.036). Moderate positive correlation was observed between ITU and initial NRS-11. Age and initial NRS-11 significantly predicted uptake.

CONCLUSIONS

Patients with uptake in their knee(s) on SPECT/CT showed positive treatment response under conservative treatment.

The Efficacy of Acupuncture in Post-Operative Pain Management: A Systematic Review and Meta-Analysis

BACKGROUND

Postoperative pain resulting from surgical trauma is a significant challenge for healthcare providers. Opioid analgesics are commonly used to treat postoperative pain; however, these drugs are associated with a number of undesirable side effects.

OBJECTIVE

This systematic review and meta-analysis evaluated the effectiveness of acupuncture and acupuncture-related techniques in treating postoperative pain.

DATA SOURCE

MEDLINE, Cochrane Library, and EMBASE databases were searched until Sep 30, 2014.

STUDY ELIGIBILITY CRITERIA

Randomized controlled trials of adult subjects (≥ 18 years) who had undergone surgery and who had received acupuncture, electroacupuncture, or acupoint electrical stimulation for managing acute post-operative pain were included.

RESULTS

We found that patients treated with acupuncture or related techniques had less pain and used less opioid analgesics on Day 1 after surgery compared with those treated with control (P < 0.001). Sensitivity analysis using the leave-one-out approach indicated the findings are reliable and are not dependent on any one study. In addition, no publication bias was detected. Subgroup analysis indicated that conventional acupuncture and transcutaneous electric acupoint stimulation (TEAS) were associated with less postoperative pain one day following surgery than control treatment, while electroacupuncture was similar to control (P = 0.116). TEAS was associated with significantly greater reduction in opioid analgesic use on Day 1 post surgery than control (P < 0.001); however conventional acupuncture and electroacupuncture showed no benefit in reducing opioid analgesic use compared with control (P ≥ 0.142).

CONCLUSION

Our findings indicate that certain modes of acupuncture improved postoperative pain on the first day after surgery and reduced opioid use. Our findings support the use of acupuncture as adjuvant therapy in treating postoperative pain.

The topical 5% lidocaine medicated plaster in localized neuropathic pain: a reappraisal of the clinical evidence

Topical 5% lidocaine medicated plasters represent a well-established first-line option for the treatment of peripheral localized neuropathic pain (LNP). This review provides an updated overview of the clinical evidence (randomized, controlled, and open-label clinical studies, real-life daily clinical practice, and case series). The 5% lidocaine medicated plaster effectively provides pain relief in postherpetic neuralgia, and data from a large open-label controlled study indicate that the 5% lidocaine medicated plaster is as effective as systemic pregabalin in postherpetic neuralgia and painful diabetic polyneuropathy but with an improved tolerability profile. Additionally, improved analgesia and fewer side effects were experienced by patients treated synchronously with the 5% lidocaine medicated plaster, further demonstrating the value of multimodal analgesia in LNP. The 5% lidocaine medicated plaster provides continued benefit after long-term (≤7 years) use and is also effective in various other LNP conditions. Minor application-site reactions are the most common adverse events associated with the 5% lidocaine medicated plaster; there is minimal risk of systemic adverse events and drug–drug interactions. Although further well-controlled studies are warranted, the 5% lidocaine medicated plaster is efficacious and safe in LNP and may have particular clinical benefit in elderly and/or medically compromised patients because of the low incidence of adverse events.

Single- and multiple-dose pharmacokinetics of biphasic immediate-release/extended-release hydrocodone bitartrate/acetaminophen (MNK-155) compared with immediate-release hydrocodone bitartrate/ibuprofen and immediate-release tramadol HCl/acetaminophen

OBJECTIVE

To characterize the single-dose and steady-state pharmacokinetics (PK) of biphasic immediate-release/extended-release hydrocodone bitartrate/acetaminophen (IR/ER HB/APAP), IR HB/ibuprofen, and IR tramadol HCl/APAP.

METHODS

In this single-center, open-label, randomized, four-period crossover study, healthy participants received four treatments under fasted conditions: 1) a single dose of two IR/ER HB/APAP 7.5/325 mg tablets (15/650 mg total dose) on day 1, followed by two tablets every 12 hours (q12h) beginning on day 3; 2) a single dose of IR HB/ibuprofen 15/400 mg (divided as one 7.5/200 mg tablet at hour 0 and 6), followed by one tablet every 6 hours (q6h) beginning on day 3; 3) a single dose of IR tramadol HCl/APAP 75/650 mg (divided as one 37.5/325 mg tablet at hour 0 and 6), followed by one tablet q6h beginning on day 3; and 4) a single dose of three IR/ER HB/APAP 7.5/325 mg tablets (22.5/975 mg total dose) on day 1, a three-tablet initial dose at 48 hours followed by two-tablet doses q12h beginning on day 3. Hydrocodone and APAP single-dose and steady-state PK were assessed. Adverse events were monitored.

RESULTS

The PK analysis was carried out on 29 of 48 enrolled participants who completed all treatment periods. Single-dose hydrocodone exposure was similar for IR/ER HB/APAP 22.5/975 mg and IR HB/ibuprofen 15/400 mg; time to maximum observed plasma concentration was shorter and half-life was longer for IR/ER HB/APAP (22.5/975 mg and 15/650 mg) vs IR HB/ibuprofen. Single-dose APAP exposure was similar for IR/ER HB/APAP 15/650 mg and IR tramadol HCl/APAP 75/650 mg. Steady-state hydrocodone and APAP exposures were similar between treatments. Adverse events were similar for each treatment and typical of low-dose combination opioid analgesics. With dosing q12h, IR/ER HB/APAP had half as many concentration peaks and troughs as the comparators treated q6h.

CONCLUSION

With dosing q12h, IR/ER HB/APAP provided similar peak and total steady-state hydrocodone and APAP exposure vs IR comparators.

Best practice in the administration of analgesia in postoncological surgery

The rationale for using multimodal analgesia after any major surgery is achievement of adequate analgesia while avoiding the unwanted effects of large doses of any analgesic, in particular opioids. There are two reasons why we can hypothesize that multimodal analgesia might have a significant impact on cancer-related outcomes in the context of oncological orthopedic surgery. First, because multimodal analgesia is a key component of enhanced-recovery pathways and can accelerate return to intended oncological therapy. And second, because some of the analgesic used in multimodal analgesia (i.e., COX inhibitors, local analgesics and dexamethasone) can induce apoptosis in cancer cells and/or diminish the inflammatory response during surgery which itself can facilitate tumor growth.