A review of the efficacy and safety of opioid analgesics post-craniotomy*

Intravenous acetaminophen for postoperative supratentorial craniotomy pain: a prospective, randomized, double-blinded, placebo-controlled trial

OBJECTIVE

Acute pain control after cranial surgery is challenging. Prior research has shown that patients experience inadequate pain control post-craniotomy. The use of oral medications is sometimes delayed because of postoperative nausea, and the use of narcotics can impair the evaluation of brain function and thus are used judiciously. Few nonnarcotic intravenous (IV) analgesics exist. The authors present the results of the first prospective study evaluating the use of IV acetaminophen in patients after elective craniotomy.

METHODS

The authors conducted a randomized, double-blinded, placebo-controlled investigation. Adults undergoing elective, supratentorial craniotomies between September 2013 and June 2015 were randomized into two groups. The experimental group received 1000 mg/100 ml IV acetaminophen every 8 hours for 48 hours. The placebo group received 100 ml of 0.9% normal saline on the same schedule. Both groups were also treated with a standardized pain control algorithm. The study was powered to detect a 30% difference in the primary outcome measures: narcotic consumption (morphine equivalents, ME) at 24 and 48 hours after surgery. Patient-reported pain scores immediately postoperatively and 48 hours after surgery were also recorded.

RESULTS

A total of 204 patients completed the trial. No significant differences were found in narcotic consumption between groups at either time point (in the treatment and placebo groups, respectively, at 24 hours: 84.3 ME [95% CI 70.2–98.4] and 85.5 ME [95% CI 73–97.9]; and at 48 hours: 123.5 ME [95% CI 102.9–144.2] and 134.2 ME [95% CI 112.1–156.3]). The difference in improvement in patient-reported pain scores between the treatment and placebo groups was significant (p < 0.001).

CONCLUSIONS

Patients who received postoperative IV acetaminophen after craniotomy did not have significantly decreased narcotic consumption but did experience significantly lower pain scores after surgery. The drug was well tolerated and safe in this patient population.

Sumatriptan improves postoperative quality of recovery and reduces postcraniotomy headache after cranial nerve decompression

BACKGROUND

Microvascular decompression (MVD) is a surgical treatment for cranial nerve disorders via a small craniotomy. The postoperative pain of this procedure can be classified as surgical site somatic pain and postcraniotomy headache similar in nature to a migraine, including its association with photophobia, nausea, and vomiting. This headache can be difficult to treat and can impact on postoperative recovery. Sumatriptan is used to treat migraine-like headaches in various settings. This single-centre randomized controlled trial investigated whether postoperative administration of sumatriptan after MVD surgery impacts the quality of postoperative recovery.

METHODS

Fifty patients who complained of postoperative headache after MVD were randomized to receive an s.c. injection of sumatriptan (6 mg) or saline. The primary outcome was quality of recovery as measured by the Quality of Recovery-40 (QoR-40) score at 24 h.

RESULTS

The QoR-40 scores were significantly higher in the sumatriptan group (median 184; interquartile range 169-196) than in the placebo group (133; 119-155; P<0.01), suggesting higher quality of recovery. The sumatriptan group also had significantly lower headache scores at 4, 12, and 24 h. There were no significant differences in other secondary outcomes.

CONCLUSIONS

Use of sumatriptan improved the quality of recovery as measured by the QoR-40 and reduction of headache at 24 h after surgery. Sumatriptan is a useful alternative treatment for postcraniotomy headache. The mechanism remains unknown but could be related to reduction in headache, mood modulation, or both, mediated by a serotonin effect.

CLINICAL TRIAL REGISTRATION

NCT01632657.

A prospective time-series quality improvement trial of a standardized analgesia protocol to reduce postoperative pain among neurosurgery patients

OBJECTIVE The inclusion of the pain management domain in the Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) survey now ties patients' perceptions of pain and analgesia to financial reimbursement for inpatient stays. Therefore, the authors wanted to determine if a quality improvement initiative centered on a standardized analgesia protocol could significantly reduce postoperative pain among neurosurgery patients. METHODS The authors implemented a 10-month, prospective, interrupted time-series trial of a quality improvement initiative. The intervention consisted of a multimodal, interdepartmental, standardized analgesia protocol with process improvements from preadmission to discharge. All neurosurgical-floor patients participated in the quality improvement intervention, with data collected on a systematically randomly sampled subset of 96 patients for detailed analysis. Patient-reported numeric rating scale pain on the first postoperative day (POD) served as the primary outcome. RESULTS Implementation of the analgesia protocol resulted in improved preoperative and postoperative documentation of pain (p < 0.001) and improved use of multimodal analgesia, including use of NSAIDs (p < 0.009) and gabapentin (p < 0.027). This intervention also correlated with a 32% reduction in reported pain on the 1st POD for all neurosurgical patients (mean pain scale scores 4.31 vs 2.94; p = 0.000) and a 43% reduction among spinal surgery patients (mean pain scale scores 5.45 vs 3.10; p = 0.036). After controlling for covariates, implementation of the protocol was a significant predictor of lowered postoperative pain (p = 0.05) on the 1st POD. This reduction in pain correlated with protocol compliance (p = 0.028), and a significant decrease in the monthly number of naloxone doses suggests improved safety (mean dose ± SD 1.5 ± 1.0 vs 0.33 ± 0.5; p = 0.04). Furthermore, a significant and persistent reduction in the pain management component of the HCAHPS scores suggests a durability of results extending beyond the life of the study (72.1% vs 82.0%; p = 0.033). CONCLUSIONS The implementation of a standardized analgesia protocol can significantly reduce postoperative pain among neurosurgical patients while increasing safety. Given the current climate of patient-centered outcomes, this study has broad implications for the continuum of care model proposed in the Affordable Care Act. Clinical trial registration no.: NCT01693588 ( clincaltrials.gov ).

Options for perioperative pain management in neurosurgery

Moderate-to-severe pain following neurosurgery is common but often does not get attention and is therefore underdiagnosed and undertreated. Compounding this problem is the traditional belief that neurosurgical pain is inconsequential and even dangerous to treat. Concerns about problematic effects associated with opioid analgesics such as nausea, vomiting, oversedation, and increased intracranial pressure secondary to elevated carbon dioxide tension from respiratory depression have often led to suboptimal postoperative analgesic strategies in caring for neurosurgical patients. Neurosurgical patients may have difficulty or be incapable of communicating their need for analgesics due to neurologic deficits, which poses an additional challenge. Postoperative pain control should be a priority, because pain adversely affects recovery and patient outcomes. Inconsistent practices and the quality of current analgesic strategies for neurosurgical patients still leave room for improvement. Given the complexity of postoperative pain management for these patients, multimodal strategies are often required to optimize pain control and at the same time limit undesired side effects.

Morphine Glucuronidation and Elimination in Intensive Care Patients: A Comparison with Healthy Volunteers

BACKGROUND

Although morphine is used frequently to treat pain in the intensive care unit, its pharmacokinetics has not been adequately quantified in critically ill patients. We evaluated the glucuronidation and elimination clearance of morphine in intensive care patients compared with healthy volunteers based on the morphine and morphine-3-glucuronide (M3G) concentrations.

METHODS

A population pharmacokinetic model with covariate analysis was developed with the nonlinear mixed-effects modeling software (NONMEM 7.3). The analysis included 3012 morphine and M3G concentrations from 135 intensive care patients (117 cardiothoracic surgery patients and 18 critically ill patients), who received continuous morphine infusions adapted to individual pain levels, and 622 morphine and M3G concentrations from a previously published study of 20 healthy volunteers, who received an IV bolus of morphine followed by a 1-hour infusion.

RESULTS

For morphine, a 3-compartment model best described the data, whereas for M3G, a 1-compartment model fits best. In intensive care patients with a normal creatinine concentration, a decrease of 76% was estimated in M3G clearance compared with healthy subjects, conditional on the M3G volume of distribution being the same in intensive care patients and healthy volunteers. Furthermore, serum creatinine concentration was identified as a covariate for both elimination clearance of M3G in intensive care patients and unchanged morphine clearance in all patients and healthy volunteers.

CONCLUSIONS

Under the assumptions in the model, M3G elimination was significantly decreased in intensive care patients when compared with healthy volunteers, which resulted in substantially increased M3G concentrations. Increased M3G levels were even more pronounced in patients with increased serum creatinine levels. Model-based simulations show that, because of the reduction in morphine clearance in intensive care patients with renal failure, a 33% reduction in the maintenance dose would result in morphine serum concentrations equal to those in healthy volunteers and intensive care patients with normal renal function, although M3G concentrations remain increased. Future pharmacodynamic investigations are needed to identify target concentrations in this population, after which final dosing recommendations can be made.

Pain Management in Post-Craniotomy Patients: A Survey of Canadian Neurosurgeons

Introduction:

Despite the growing recognition for analgesic needs in post-craniotomy patients, this remains a poorly studied area in neurological surgery. The class and regimen of analgesia that is most suitable for these patients remains controversial. The objective of this study is to examine the current beliefs and practices of Canadian neurosurgeons when managing post-craniotomy pain.

Methods:

A survey was sent to all practicing Canadian neurosurgeons to examine the following aspects of analgesia in craniotomy patients: type of analgesics used, common side effects encountered, satisfaction with current regimen and the rationale for their practice.

Results:

Of 156 potential respondents, 103 neurosurgeons (66%) completed the survey. Codeine (59%) was the most prescribed firstline analgesic followed by morphine (38%). The use of a second-line opioid was significantly higher among codeine prescribers compared to morphine, 53% compared to 28% (p < 0.001). Nausea, constipation and neurologic depression were reported as common side effects by 76%, 66% and 27% of respondents respectively. Of the respondents, 90% reported a high level of satisfaction with their current choice of analgesia; nonetheless, they predominantly described their practice as personal preference or protocol driven rather than evidence-based.

Conclusions:

Codeine - a weak opioid - is the most common first-line analgesic prescribed to craniotomy patients. This practice is associated with substantially increased reliance on potent opioids for rescue analgesia. Whether novel regimens can provide optimal pain control while minimizing neurologic and gastrointestinal side effects remains to be addressed by future trials.

Safety and efficacy of continuous morphine infusions following pediatric cranial surgery in a surgical ward setting

PURPOSE

Morphine is avoided by many neurosurgeons following cranial surgery. There exists a concern regarding the potential complications and a perception that cranial surgery is less painful than other surgical procedures. At British Columbia Children's Hospital continuous morphine infusions (CMI) have been used to control pain in pediatric neurosurgical patients. The purpose of this study was to compare the safety and efficacy of continuous intravenous morphine infusion to standard oral analgesics in a neurosurgical ward setting.

METHODS

A retrospective review of medical records for 71 children was completed. The patients underwent either cranial reconstruction (2002-2007) or craniotomies for intradural pathology (2005-2007) at British Columbia Children's Hospital. Outcome measures included pain control and adverse events. Comparison was made between patients receiving a CMI and patients receiving acetaminophen and codeine.

RESULTS

Thirty-seven children received CMI on the ward (30 cranial reconstruction and 7 craniotomy), while 34 (10 cranial reconstruction and 24 craniotomy) received acetaminophen and codeine. There was no statistical difference in pain control. There was significantly more nausea on post-operative day one in the CMI group (p = 0.002). There were no other significant adverse events.

CONCLUSIONS

These findings suggest that CMI is comparable to acetaminophen and codeine with respect to analgesia and serious side effects. We recommend the use of CMIs as an alternative when pain is poorly controlled in post-operative pediatric neurosurgical patients to prevent the potential adverse consequences of inadequate analgesia.

Postoperative pain management with tramadol after craniotomy: evaluation and cost analysis

OBJECT

Patients undergoing craniotomies have traditionally received opiates with acetaminophen for the management of their postoperative pain. The use of narcotic pain medications can be costly, decrease rates of early postoperative ambulation, lengthen hospital stays, and alter a patient's neurological examination. The use of alternative pain medications such as tramadol may benefit patients by resolving many of these issues.

METHODS

The authors conducted a randomized, blinded prospective study to evaluate the efficacy of alternative pain management strategies for patients following craniotomies. Fifty patients were randomly assigned either to a control group who received narcotics and acetaminophen alone or an experimental group who received tramadol in addition to narcotic pain medications (25 patients assigned to each group).

RESULTS

The control group was noted to have statistically significant higher visual analog scale pain scores, an increased length of hospital stay, and increased narcotic use compared with the tramadol group. The narcotics and acetaminophen group also had increased hospitalization costs when compared with the tramadol group.

CONCLUSIONS

The use of scheduled atypical analgesics such as tramadol in addition to narcotics with acetaminophen for the management of postoperative pain after craniotomy may provide better pain control, decrease the side effects associated with narcotic pain medications, encourage earlier postoperative ambulation, and reduce total hospitalization costs.

Efficacy of intravenous patient-controlled analgesia after supratentorial intracranial surgery: a prospective randomized controlled trial. Clinical article

OBJECT

Opioid administration following major intracranial surgery is often limited by a presumed lack of need and a concern that opioids will adversely affect postoperative outcome and interfere with the neurological examination. Nevertheless, evidence is accumulating that these patients suffer moderate to severe postoperative pain and that this pain is often undertreated. The authors hypothesized that intravenous patient-controlled analgesia (PCA) would safely and more effectively treat postoperative supratentorial craniotomy pain than conventional as needed (PRN) therapy.

METHODS

Following a standardized course of general anesthesia, adult patients who underwent elective supratentorial intracranial surgery were randomized in the neurosciences intensive care unit to receive either PRN intravenous fentanyl 25-50 microg every 30 minutes or PCA intravenous fentanyl 0.5 microg/kg every 15 minutes (maximum 4 doses/hour). The authors measured pain (self-reported scale score [0-10]), sedation (Ramsay Sedation Scale score), Glasgow Coma Scale score, fentanyl use, and major adverse events (excessive sedation, respiratory depression, pruritus, nausea, or vomiting) hourly.

RESULTS

Sixty-four patients with a mean age of 48 years (range 22-77 years) were randomized to intravenous PCA (29 patients) or PRN fentanyl (35 patients) groups. There were no statistically significant demographic differences between the 2 groups. Patients receiving intravenous PCA had significantly lower pain scores than those receiving intravenous PRN fentanyl (2.53 +/- 1.96 vs 3.62 +/- 2.11 [p = 0.039]) and received significantly more fentanyl than the PRN group (44.1 +/- 34.5 vs 23.6 +/- 23.7 microg/hour [p = 0.007]). There were no differences between the 2 groups regarding the number of patients with adverse events.

CONCLUSIONS

Intravenous PCA more effectively treats the pain of supratentorial intracranial surgery than PRN fentanyl, and patients in the former group did not experience any untoward events related to the self-administration of opioids.

Postoperative pain management after craniotomy: evaluation and cost analysis

OBJECTIVE

Patients undergoing craniotomies have traditionally received opiates for the management of their postoperative pain. The use of narcotic pain medications can be costly, can decrease early walking, can lengthen hospital stay, and can alter a patient's neurological examination results. The use of alternative pain medications such as cyclooxygenase-2 (COX-2) inhibitors may benefit patients by resolving many of these issues. Compared with traditional nonsteroidal anti-inflammatory drugs, these anti-inflammatory medications may be used safely in neurosurgical patients because of their selective inhibition of the COX-2 enzyme, which avoids the platelet dysfunction caused by other nonsteroidal anti-inflammatory drugs.

METHODS

A randomized, single-blinded prospective study was used to evaluate the efficacy of alternative pain management strategies for patients who have undergone craniotomy. Twenty-seven patients were randomly assigned to a control group (n = 13) receiving narcotics alone or an experimental group (n = 14) receiving a COX-2 inhibitor in addition to narcotic pain medications.

RESULTS

The narcotics group was noted to have statistically significantly higher visual analog scale scores, increased length of stay, and increased narcotic use compared with the COX-2 group. The narcotics group also had increased hospitalization costs when compared with the COX-2 group.

CONCLUSION

The use of scheduled atypical analgesics, such as COX-2 inhibitors, in addition to narcotics for the management of postoperative pain after craniotomy may provide better pain control, may decrease side effects associated with narcotic pain medications, may encourage earlier walking, and may reduce total hospitalization costs.

Postoperative pain, nausea and vomiting in neurosurgical patients

PURPOSE OF REVIEW

Postoperative pain and postoperative nausea and vomiting are significant problems for neurosurgical patients and their carers. The treatment of these problems is widely perceived to be inadequate, however, especially in patients undergoing craniotomy, and there are few large, randomized controlled trials. The main issue has been fear of side effects, especially those masking neurological signs. A review of the recent literature therefore is justified.

RECENT FINDINGS

Very little new information has been added to the literature about pain management in craniotomy patients, and postoperative nausea and vomiting management in neurosurgery patients as a whole. The main themes in the literature have been the introduction of multimodal analgesia for craniotomy patients, using simple analgesics as adjuvants to opioids, and innovative neuroaxial analgesia techniques in spinal surgery patients.

SUMMARY

There is still a lot of scope to research and refine pain and postoperative nausea and vomiting management in cranial and spinal neurosurgical patients. Large-scale studies are required to define the current state of practice, determine effective treatments and define the incidence of side-effects.