Fentanyl versus remifentanil-based TIVA for pediatric scoliosis repair: does it matter?

Anesthesia and Pain Management for Scoliosis Surgery: A Narrative Review

STUDY DESIGN

This was a narrative review.

OBJECTIVE

The objective of this review was to summarize the current evidence and knowledge gaps regarding anesthesia and pain management for scoliosis surgery, including multimodal analgesia, and identify the best anesthetic approach to scoliosis surgery that ensures patient safety and pain relief even in the postoperative period, with minimal influence on SSEP monitoring.

SUMMARY OF BACKGROUND DATA

Spinal surgeries and fusions for scoliosis are associated with high pain levels. Inadequate analgesia can cause patient dissatisfaction, delay recovery, and increase the risk of chronic pain. Despite serious side effects, opioids are the mainstay of pain medication after scoliosis surgery. However, increasing emphasis on minimizing opioids and accelerating recovery has increased the adoption of multimodal analgesic therapy.

MATERIALS AND METHODS

The literature review was performed on standards of care, a pain management protocol, current therapeutic options, and innovative treatment options for patients undergoing scoliosis surgery. The literature was reviewed through 4 electronic databases: PubMed, Cochrane Library, Google Scholar, and Embase.

RESULTS

The initial search yielded 994 articles. Forty-seven relevant articles were selected based on relevance, recentness, search quality, and citations. Ten studies described the influence of different methods of anesthesia on neuromonitoring. Twenty-one researchers studied the effect of analgesics and coanalgesics on pain relief protocol. Nine studies treated regional anesthesia and its influence on pain management.

CONCLUSIONS

The most suitable anesthetic approach that does not disturb the neuromonitoring is obtained by combining total intravenous anesthesia (TIVA) with remifentanil and propofol with regional anesthesia, particularly erector spinae plane block (ESPB), as a part of a multimodal analgesia protocol.

LEVEL OF EVIDENCE

Level II.

The Influence of Anesthesia on Neuromonitoring During Scoliosis Surgery: A Systematic Review

BACKGROUND

Intraoperative neuromonitoring (IONM) is crucial for the safety of scoliosis surgery, providing real-time feedback on the spinal cord and nerve function, primarily through motor-evoked potentials (MEPs). The choice of anesthesia plays a crucial role in influencing the quality and reliability of these neuromonitoring signals. This systematic review evaluates how different anesthetic techniques-total intravenous anesthesia (TIVA), volatile anesthetics, and regional anesthesia approaches such as Erector Spinae Plane Block (ESPB), spinal, and epidural anesthesia-affect IONM during scoliosis surgery.

METHODS

A systematic review was conducted following PRISMA guidelines. PubMed, MEDLINE, EMBASE, and Cochrane databases were searched for studies published between 2017 and 2024 that examined the impact of anesthetic techniques on neuromonitoring during scoliosis surgery. The focus was on studies reporting MEP outcomes, anesthetic protocols, and postoperative neurological and analgesic effects.

RESULTS

The search initially identified 998 articles. After applying inclusion criteria based on relevance, recency, methodological quality, and citation frequency, 45 studies were selected for detailed review.

CONCLUSION

The erector Spinae Plane Block (ESPB) provides distinct benefits over spinal and epidural anesthesia in scoliosis surgery, particularly in maintaining neuromonitoring accuracy, reducing hemodynamic instability, and minimizing complications. The ESPB's ability to deliver effective segmental analgesia without compromising motor function makes it a safer and more efficient option for postoperative pain management, enhancing patient outcomes.

A survey of practice in the anesthetic management of adolescent idiopathic scoliosis spine fusion by the North American Pediatric Spine Anesthesiologists Collaborative

BACKGROUND

Adolescent Idiopathic Scoliosis (AIS) affects 2%-4% of the general pediatric population. While surgical correction remains one of the most common orthopedic procedures performed in pediatrics, limited consensus exists on the perioperative anesthetic management.

AIMS

To examine the current state of anesthetic management of typical AIS spine fusions at institutions which have a dedicated pediatric orthopedic spine surgeon.

METHODS

A web-based survey was sent to all members of the North American Pediatric Spine Anesthesiologists (NAPSA) Collaborative. This group included 34 anesthesiologists at 19 different institutions, each of whom has a Harms Study Group surgeon performing spine fusions at their hospital.

RESULTS

Thirty-one of 34 (91.2%) anesthesiologists completed the survey, with a missing response rate from 0% to 16.1% depending on the question. Most anesthesia practices (77.4%; 95% confidence interval [CI], 67.7-93.4) do not have patients come for a preoperative visit prior to the day of surgery. Intravenous induction was the preferred method (74.2%; 95% CI 61.3-89.9), with the majority utilizing two peripheral IVs (93.5%; 95% CI 90.3-100) and an arterial line (100%; 95% CI 88.8-100). Paralytic administration for intubation and/or exposure was divided (51.6% rocuronium/vecuronium, 45.2% no paralytic, and 3.2% succinylcholine) amongst respondents. While tranexamic acid was consistently utilized for reducing blood loss, dosing regimens varied. When faced with neuromonitoring signal issues, 67.7% employ a formal protocol. Most anesthesiologists (93.5%; 95% CI 78.6-99.2) extubate immediately postoperatively with patients admitted to an inpatient floor bed (77.4%; 95% CI 67.7-93.3).

CONCLUSION

Most anesthesiologists (87.1%; 95% CI 80.6-99.9) report the use of some form of an anesthesia-based protocol for AIS fusions, but our survey results show there is considerable variation in all aspects of perioperative care. Areas of agreement on management comprise the typical vascular access required, utilization of tranexamic acid, immediate extubation, and disposition to a floor bed. By recognizing the diversity of anesthetic care, we can develop areas of research and improve the perioperative management of AIS.

Nausea and Vomiting After Posterior Spinal Fusion in Adolescent Idiopathic Scoliosis: A Systematic and Critical Analysis Review

BACKGROUND

Postoperative nausea and vomiting (PONV) affects patient satisfaction, health care costs, and hospital stay by complicating the postoperative recovery period after adolescent idiopathic scoliosis (AIS) spinal fusion surgery. Our goal was to identify recommendations for optimal management of PONV in AIS patients undergoing posterior spinal fusion (PSF).

METHODS

We performed a systematic review in June 2022, searching the PubMed and Embase electronic databases using search terms "(Adolescent idiopathic scoliosis) AND (Postoperative) AND (Nausea) AND (Vomiting)." Three authors reviewed the 402 abstracts identified from January 1991 to June 2022. Studies that included adolescents or young adults (<21 years) with AIS undergoing PSF were selected for full-text review by consensus. We identified 34 studies reporting on incidence of PONV. Only 6 studies examined PONV as the primary outcome, whereas remaining were reported PONV as a secondary outcome. Journal of Bone and Joint Surgery Grades of recommendation were assigned to potential interventions or clinical practice influencing incidence of PONV with respect to operative period (preoperative, intraoperative, and postoperative period) on the basis that potential guidelines/interventions for PONV can be targeted at those periods.

RESULTS

A total of 11 factors were graded, 5 of which were related to intervention and 6 were clinical practice-related. Eight factors could be classified into the operative period-1 in the intraoperative period and 7 in the postoperative period, whereas the remaining 3 recommendations had overlapping periods. The majority of grades of recommendations given were inconclusive or conflicting. The statement that neuraxial and postoperative systemic-only opioid therapy have a similar incidence of PONV was supported by good (Grade A) evidence. There was fair (Grade B) and poor evidence (Grade C) to avoid opioid antagonists and nonopioid local analgesia using wound catheters as PONV-reducing measures.

CONCLUSION

Although outcomes after spinal fusion for AIS have been studied extensively, the literature on PONV outcomes is scarce and incomplete. PONV is most commonly included as a secondary outcome in studies related to pain management. This study is the first to specifically identify evidence and recommendations for interventions or clinical practice that influence PONV in AIS patients undergoing PSF. Most interventions and clinical practices have conflicting or limited data to support them, whereas others have low-level evidence as to whether the intervention/clinical practice influences the incidence of PONV. We have identified the need for expanded research using PONV as a primary outcome in patients with AIS undergoing spinal fusion surgery.

Error traps and preventative strategies for adolescent idiopathic scoliosis spinal surgery

Anesthesia for posterior spinal fusion for adolescent idiopathic scoliosis remains one of the most common surgeries performed in adolescents. These procedures have the potential for significant intraprocedural and postoperative complications. The potential for pressure injuries related to prone positioning must be understood and addressed. Additionally, neuromonitoring remains a mainstay for patient care in order to adequately assess patient neurologic integrity and alert the providers to a reversible action. As such, causes of neuromonitoring signal loss must be well understood, and the provider should have a systematic approach to signal loss. Further, anesthetic design must facilitate intraoperative wake-up to allow for a definitive assessment of neurologic function. Perioperative bleeding risk is high in posterior spinal fusion due to the extensive surgical exposure and potentially lengthy operative time, so the provider should undertake strategies to reduce blood loss and avoid coagulopathy. Pain management for adolescents undergoing spinal fusion is also challenging, and inadequate analgesia can delay recovery, impede patient/family satisfaction, increase the risk of chronic postsurgical pain/disability, and lead to prolonged opioid use. Many of the significant complications associated with this procedure, however, can be avoided with intentional and evidence-based approaches covered in this review.

Association between intraoperative remifentanil use and postoperative hyperalgesia in adolescent idiopathic scoliosis surgery: a retrospective study

BACKGROUND

The liberal use of remifentanil in spine surgery has been associated with an increased incidence of postoperative hyperalgesia. Nevertheless, controversies remain as the existing evidence is inconclusive to determine the relationship between remifentanil use and the development of opioid-induced hyperalgesia. We hypothesized that intraoperative infusion of higher dose remifentanil during scoliosis surgery is associated with postoperative hyperalgesia, manifesting clinically as greater postoperative morphine consumption and pain scores.

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.

Amygdala Metabotropic Glutamate Receptor 1 Influences Synaptic Transmission to Participate in Fentanyl-Induced Hyperalgesia in Rats

The underlying mechanisms of opioid-induced hyperalgesia (OIH) remain unclear. Herein, we found that the protein expression of metabotropic glutamate receptor 1 (mGluR1) was significantly increased in the right but not in the left laterocapsular division of central nucleus of the amygdala (CeLC) in OIH rats. In CeLC neurons, the frequency and the amplitude of mini-excitatory postsynaptic currents (mEPSCs) were significantly increased in fentanyl group which were decreased by acute application of a mGluR1 antagonist, A841720. Finally, the behavioral hypersensitivity could be reversed by A841720 microinjection into the right CeLC. These results show that the right CeLC mGluR1 is an important factor associated with OIH that enhances synaptic transmission and could be a potential drug target to alleviate fentanyl-induced hyperalgesia.

Spinal microRNA-134-5p targets glutamate receptor ionotropic kainate 3 to modulate opioid induced hyperalgesia in mice

Background: Fentanyl and its analogs are extensively used for pain relief. However, their paradoxically pronociceptive effects often lead to increased opioids consumption and risk of chronic pain. Compared to other synthetic opioids, remifentanil has been strongly linked to acute opioid hyperalgesia after exposure [remifentanil-induced hyperalgesia (RIH)]. The epigenetic regulation of microRNAs (miRNAs) on targeted mRNAs has emerged as an important pathogenesis in pain. The current research aimed at exploring the significance and contributions of miR-134-5p to the development of RIH. Methods: Both the antinociceptive and pronociceptive effects of two commonly used opioids were assessed, and miRNA expression profiles in the spinal dorsal horn (SDH) of mice acutely exposed to remifentanil and remifentanil equianalgesic dose (RED) sufentanil were screened. Next, the candidate miRNA level, cellular distribution, and function were examined by qPCR, fluorescent in situ hybridization (FISH) and Argonaute-2 immunoprecipitation. Furthermore, bioinformatics analysis, luciferase assays, miRNA overexpression, behavioral tests, golgi staining, electron microscopy, whole-cell patch-clamp recording, and immunoblotting were employed to investigate the potential targets and mechanisms underlying RIH. Results: Remifentanil induced significant pronociceptive effects and a distinct miRNA-profile from sufentanil when compared to saline controls. Among top 30 differentially expressed miRNAs spectrum, spinal miR-134-5p was dramatically downregulated in RIH mice but remained comparative in mice subjected to sufentanil. Moreover, Glutamate Receptor Ionotropic Kainate 3 (Grik3) was a target of miR-134-5p. The overexpression of miR-134-5p attenuated the hyperalgesic phenotype, excessive dendritic spine remodeling, excitatory synaptic structural plasticity, and Kainate receptor-mediated miniature excitatory postsynaptic currents (mEPSCs) in SDH resulting from remifentanil exposure. Besides, intrathecal injection of selective KA-R antagonist was able to reverse the GRIK3 membrane trafficking and relieved RIH. Conclusion: The miR-134-5p contributes to remifentanil-induced pronociceptive features via directly targeting Grik3 to modulate dendritic spine morphology and synaptic plasticity in spinal neurons.

Knowing the Enemy Is Halfway towards Victory: A Scoping Review on Opioid-Induced Hyperalgesia

Opioid-induced hyperalgesia (OIH) is a paradoxical effect of opioids that is not consensually recognized in clinical settings. We conducted a revision of clinical and preclinical studies and discuss them side by side to provide an updated and renewed view on OIH. We critically analyze data on the human manifestations of OIH in the context of chronic and post-operative pain. We also discuss how, in the context of cancer pain, though there are no direct evidence of OIH, several inherent conditions to the tumor and chemotherapy provide a substrate for the development of OIH. The review of the clinical data, namely in what concerns the strategies to counter OIH, emphasizes how much OIH rely mechanistically on the existence of µ-opioid receptor (MOR) signaling through opposite, inhibitory/antinociceptive and excitatory/pronociceptive, pathways. The rationale for the maladaptive excitatory signaling of opioids is provided by the emerging growing information on the functional role of alternative splicing and heteromerization of MOR. The crossroads between opioids and neuroinflammation also play a major role in OIH. The latest pre-clinical data in this field brings new insights to new and promising therapeutic targets to address OIH. In conclusion, although OIH remains insufficiently recognized in clinical practice, the appropriate diagnosis can turn it into a treatable pain disorder. Therefore, in times of scarce alternatives to opioids to treat pain, mainly unmanageable chronic pain, increased knowledge and recognition of OIH, likely represent the first steps towards safer and efficient use of opioids as analgesics.

Effect of Dexmedetomidine Compared to Remifentanil During Bariatric Surgery on Postoperative Nausea and Vomiting: a Retrospective Study

PURPOSE

Postoperative nausea and vomiting (PONV) occurs frequently after bariatric surgery and is a major cause of adverse outcomes. This retrospective study investigated whether opioid-restricted total intravenous anesthesia using dexmedetomidine as a substitute for remifentanil can reduce PONV in bariatric surgery.

MATERIALS AND METHODS

The electronic medical records of adult patients who underwent laparoscopic bariatric surgery between January and December 2019 were reviewed. The patients were divided into two groups according to the agents used for anesthesia: Group D, propofol and dexmedetomidine; Group R, propofol and remifentanil.

RESULTS

A total of 134 patients were included in the analyses. The frequency of postoperative nausea was significantly lower in Group D than that in Group R until 2 h after discharge from the postanesthesia care unit (PACU) (P = 0.005 in the PACU, P = 0.010 at 2 h after PACU discharge) but failed to significantly reduce the overall high incidence rates of 60.5% and 65.5%, respectively (P = 0.592). Postoperative pain score was significantly lower in Group D until 6 h after PACU discharge. The rates of rescue antiemetic and analgesic agent administration in the PACU were significantly lower in Group D than those in Group R.

CONCLUSION

Opioid-restricted total intravenous anesthesia using dexmedetomidine reduces postoperative nausea, pain score, antiemetic, and analgesic requirements in the immediate postoperative period after bariatric surgery.

Intraoperative Remifentanil Dosage in Surgery for Adolescent Idiopathic Scoliosis Does Not Increase Postoperative Opioid Consumption When Combined With Epidural Analgesia: A Retrospective Cohort Study

Background In adults, high-dose remifentanil during surgery has been reported to increase postoperative opioid consumption, but this has not been well documented in children. Multimodal analgesia is recommended in the perioperative period for adolescent idiopathic scoliosis (AIS), but no report has examined opioid consumption under epidural analgesia, which is one of the most common types of analgesia. Aims To investigate the association between intraoperative remifentanil dosage and postoperative opioid consumption in AIS in the setting of combined epidural analgesia for postoperative multimodal analgesia. Methods In this retrospective cohort study, patients aged 10-18 years who underwent surgery for scoliosis and epidural analgesia for postoperative pain between July 2012 and April 2019 were included. The primary endpoint was the association between intraoperative cumulative weight-adjusted remifentanil dosage and logarithmic transformation of cumulative weight-adjusted fentanyl consumption in the intensive care unit (ICU). Nonopioid analgesics were investigated as secondary endpoints. An epidural catheter was inserted by the surgeon intraoperatively, and a local anesthetic was administered at the end of the surgery. Multivariate linear regression analysis with adjustment for confounders was performed for all analyses. Results In total, 142 patients were included, and the median intraoperative remifentanil dosage for all patients was 0.27 (interquartile range, 0.24-0.34) µg/kg/min. No association was observed between cumulative weight-adjusted intraoperative dosage of remifentanil and fentanyl, even after adjusting for potential confounders (slope = -1.25; 95% confidence interval [CI], -4.35 to 1.85; P = 0.43). No association was observed between nonopioid analgesic use and intraoperative remifentanil dosage. Conclusion No association was noted between remifentanil dosage during surgery for AIS and postoperative opioid consumption with epidural analgesia. However, this study has limitations due to its retrospective design; thus, further prospective studies are warranted.

In the Arms of Morpheus without Morphia; Mitigating the United States Opioid Epidemic by Decreasing the Surgical Use of Opioids

The opioid epidemic is a major public health issue in the United States. Exposure of opioid naïve-patients to opioids in the perioperative period is a well-documented source of continued use with one in 20 opioid-naïve surgical patients continuing to use opioids beyond 90 days. There is no association with magnitude of surgery, major versus minor, and the strongest predictor of continued use is surgical exposure. Causal factors include over reliance on opioids for intraoperative and postoperative analgesia and excessive ambulatory opioid prescribing. Opioid-induced hyperalgesia can paradoxically result from intraoperative (anesthesia controlled) opioid administration. Increasing size of initial prescription is a strong predictor of continued use necessitating procedure specific supplies limited to under 3-days. Alternative multimodal pain management (non-opioid medications and regional anesthesia) that limit opioid use must be a high priority with opioids reserved for severe breakthrough pain. Barriers to implementation of opioid-sparing pathways include reluctance to adopt protocols and apprehension about opioid elimination. Considering the number of surgeries performed annually in the United States, perioperative physicians must aggressively address modifiable factors in surgical patients. Patient care pathways need to be constructed collaboratively by surgeons and anesthesiologists with continuing feedback to optimize patient outcomes including iatrogenic opioid dependence.

Postoperative Pain Management in Pediatric Spinal Fusion Surgery for Idiopathic Scoliosis

This article reviews and summarizes current evidence and knowledge gaps regarding postoperative analgesia after pediatric posterior spine fusion for adolescent idiopathic scoliosis, a common procedure that results in severe acute postoperative pain. Inadequate analgesia may delay recovery, cause patient dissatisfaction, and increase chronic pain risk. Despite significant adverse effects, opioids are the analgesic mainstay after scoliosis surgery. However, growing emphasis on opioid minimization and enhanced recovery has increased adoption of multimodal analgesia (MMA) regimens. While opioid adverse effects remain a concern, MMA protocols must also consider risks and benefits of adjunct medications. We discuss use of opioids via different administration routes and elaborate on the effect of MMA components on opioid/pain and recovery outcomes including upcoming regional analgesia. We also discuss risk for prolonged opioid use after surgery and chronic post-surgical pain risk in this population. Evidence supports use of neuraxial opioids at safe doses, low-dose ketorolac, and methadone for postoperative analgesia. There may be a role for low-dose ketamine in those who are opioid-tolerant or have chronic pain, but the evidence for preoperative gabapentinoids and intravenous lidocaine is currently insufficient. There is a need for further studies to evaluate pediatric-specific optimal MMA dosing regimens after scoliosis surgery. Questions remain regarding how best to prevent acute opioid tolerance, opioid-induced hyperalgesia, and chronic postsurgical pain. We anticipate that this timely update will enable clinicians to develop efficient pain regimens and provide impetus for future research to optimize recovery outcomes after spine fusion.