Strategies for peri-surgical opioid management in spinal surgery patients

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Jean-Pierre Mobasser

Jean-Pierre Mobasser, Robert Hastings and Dillon Mobasser of the Goodman Campbell Brain and Spine Institute (Indianapolis, USA) and Indiana Spine Hospital (Carmel, USA) share their experience of and strategy for peri-surgical opioid management in spinal surgery patients.

The opioid crisis has been developing over the past 20 years in our country, starting with the government directive that we treat pain as the fifth vital sign. Surgeons were put in the untenable position of either prescribing narcotics to the level of a patient’s satisfaction, or potentially face consequences. Even if we suspected this to have unintended consequences, there was little choice but to comply.

We now know that one out of 15 surgical patients who receive an opioid prescription after surgery will become chronic narcotic abusers (44% more likely to become opioid abusers within one year).1,2 Just as tragically, 2018 NIH data shows that 128 people die each day in the USA from opioid overdose. In addition, we know that opioid-related adverse effects increase morbidity and drive up hospital costs substantially.3,4

The cost of opioid-related morbidity is significant. The US healthcare system cannot afford to continue treating pain as we have in the past. Our patients deserve better and our healthcare dollars must be utilised better. Mortality is dramatically influenced by opioid-related adverse events (ORAEs). Patients who experience ORAEs add to healthcare costs. The mean difference in length of stay in surgical patients with ORAEs is 6.8 vs. 5.2 days, the cost of hospitalisation is US$25,599 vs. US$17,374, the mortality is 3% vs. 0.1%, and the 30 day readmission is 8.9% vs. 7.1%.4 This is not sustainable.

Opioid-related adverse events include respiratory depression. Obstructive sleep apnea patients are at risk for life-threatening apneic/hypoxic events. Opioids also lead to decreased GI motility potentially resulting in constipation, ileus, or bowel obstruction. Cognitive dysfunction is a frequent problem which can range from postoperative confusion to delirium. Nausea/vomiting and urinary retention are also common with opioid use. Perhaps the most devastating adverse effect is opioid-induced hyperalgesia (OIH). OIH is a condition where patients exposed to chronic doses of opioids are more sensitive to any painful stimuli. In other words, chronic opioids lead to more chronic pain. Physicians are quickly becoming aware of this major problem.

Surprisingly, OIH may begin to occur faster than we previously thought. It is likely OIH occurs much more rapidly when using opioids that are ultra-short acting (rapidly metabolised). High dose remifentanil should be avoided in the OR. Patients will hurt more and require more opioids postoperatively when using high dose short-acting opioids.5, 6 Intra-op opioids, in general, should be minimised to achieve the best pain scores and lowest post-op opioid requirements. A long acting opioid like methadone may be the best choice for a low level opioid technique and for delaying the development of OIH.7,8

Rethinking the use of narcotics

We need to change our way of treating pain by rethinking the way we utilise narcotics intra-operatively, and peri-operatively. By utilising non-opioid adjuncts scheduled and/or infused, in conjunction with regional and peripheral nerve blocks, where indicated, we can reduce the need for opioids. NMDA antagonists, COX-2 inhibitors, NSAIDs, gabapentinoids, acetaminophen, and dexamethasone all work together to treat surgical pain, and reduce the need for opioids. Peripheral nerve blocks, regional blocks, IV lidocaine infusions, subcutaneous infiltration all assist in this goal.

Ketamine, an NMDA antagonist, is an excellent drug for chronic pain/opioid patients. NMDA is a key mediator to OIH. For these patients and for very painful surgeries, start the ketamine infusion upon induction of anesthesia. Very strongly consider running a sub-anesthetic dose of ketamine on the floor for 1–3  days post-op on these patients. This is a safe and effective means of reducing surgical pain.9 Low dose post-op ketamine is very well tolerated with very few side effects. Ketamine is also a mood elevator and been shown to be very effective for treatment-resistant depression. Depression and chronic pain are intimately linked, and it is important to treat depression, in order to treat pain. Contraindications include intracranial mass or haemorrhage, increased intracranial pressure, intraocular pressure, cirrhosis, pregnancy, and psychosis. Adverse reactions include cognitive deficits, hallucinations and these adverse reactions can be reduced if preceded by GABA activating drug (i.e. benzodiazepine) and if given in sub anesthetic doses. Common reactions to ketamine include elevated blood pressure and heart rate and nystagmus, so be aware of these potential findings. Our intra-operative dose is 5–10 mcg/kg/min and then post-op dose is 0.1–0.2 mg/kg/hr. for 1–3 days post-surgery. Low dosing reduces risk of side effects.

If the patient isn’t a candidate for a regional block with long acting bupivacaine, then intravenous lidocaine infusion may significantly improve post-pain scores after complex spine surgery.10 Lidocaine infusion also shows better GI motility and decreased opioid consumption with up to six hours of postoperative pain relief. Peri-operative intravenous lidocaine has also been shown to improved quality of life assessment scores at one and three months post-op after complex spine surgery.10 Contraindications to IV lidocaine infusion include unstable CAD, recent MI, CHF (EF<20%), heart block (without pacemaker), arrhythmia disorder (WPW, Adams-Stokes). Also use caution with moderate to severe hepatic disease, severe renal disease, or seizure disorder. Lidocaine i.v. infusion is 1.5 mg/kg/hr. with a maximum of eight hours.

Another effective agent in this effort to minimise opioids is dexmedetomidine (dexmed). Dexmed is an alpha-2 receptor agonist that significantly reduces opioid consumption, post-operative nausea and vomiting, post-op shivering, and stress responses.6,11 Intra-op use significantly reduces pain for 48 hours after posterior lumbar interbody fusion (PLIF) when compared to intra-op remifentanil and produces peri-operative haemodynamic stability, along with reducing the stress response after multi-level spinal surgery.6 Contraindications include: second or third degree heart block without pacemaker, sick sinus syndrome, severely depressed LV function and caution is recommended in patients with hypotension of hypovolemia. There is anecdotal concern that dexmedetomidine can depress amplitudes in motor-evoked potential monitoring, but there is no clear scientific evidence to support this concern.12,13,14 Our dosing regimen includes a loading dose 1mcg/kg over 10 min followed by a maintenance dose 0.4mcg/kg/hr.

Obesity and opioids

At our institution, we feel that it is important to prevent overdosing our morbidly obese patients with intravenous infusions. We use a quick and easy method to estimate an ideal weight for our weight-based infusion dosing. We simply apply maximum weight caps (80kg for women and 100kg for men). In doing so, we not only avoid overdosing extremely overweight patients, we also target a more exact therapeutic dosing range for these patients.

NSAIDs (and COX-2 inhibitors) are a very important component of any multi-modal peri-operative pain control plan. These drugs have been shown to both reduce the postoperative opioid requirement and improve postoperative pain scores in numerous studies. However, spinal surgeons have been reluctant to include these drugs in their pain control plans on spinal fusion surgeries because of the concern over potential increase in non-union rates. Animal studies in the early 2000s showed inhibition of bone healing when NSAIDs were used in a prolonged fashion in high doses. We now know that NSAIDs can be a safe and effective part of spinal fusion surgery pain control plan when used for less than two weeks and in recommended doses. No level 1 human studies have shown a decreased fusion rate.15

Regional blocks have become a very useful tool in post-operative pain control. Originally, we started with utilising liposomal bupivacaine for transversus abdominus plane (TAP) blocks for anterior lumbar interbody fusion (ALIF) surgery with encouraging results. This allowed us to reduce postoperative narcotic needs, and led to earlier discharge. Recent literature shows that bilateral quadratus lumborum blocks with liposomal bupivacaine can be more effective in providing visceral analgesia, in addition to the somatic analgesia of the abdominal wall that TAP blocks provide. Both blocks are effective and safe when performed with ultrasound guidance by a skilled anesthaesiologist or surgeon. Quadratus lumborum blocks anaesthetise the iliohypogastric and ilioinguinal nerves which leads to more consistent and better pain control due to a more extensive sensory blockade from T7-L2. Erector spinae plane (ESP) blocks for posterior lumbar fusion pain control also have shown some promise, but more scientific evaluation is needed.

Our institutional multi-modal low opioid pain control plan for healthy patients who are less than 65 years old and > 60 kg is listed below. This plan would be applied in very painful surgeries (i.e. open, lumbar fusions) and in patients with OID secondary to chronic opioids. Co-morbidities may dictate some medications be deleted (contraindications) or dose adjusted:

Pre-operative:

  • Celebrex 400 mg po
  • Acetaminophen 1000 mg po
  • Gabapentin 600 mg po
  • Methadone 30 mg po (20 mg for 50 kg pt, 30 mg for 75 kg pt, 40 kg for 100 mg pt)

Intra-op:

  • IntraOp Meds (dosing of infusions → use 100 kg max for men and 80 kg max for women to avoid overdosing morbidly obese patients)
  • TIVA (Propofol gtt, Ketamine gtt, Dexmedetomidine gtt, +/- Lidocaine gtt)
  • Propofol 100 mcg/kg/min
  • Ketamine 10 mcg/kg/min
  • Dexmedetomidine 1 mcg/kg over 10 min, then 0.4 mcg/kg/hr (D/C when starting closure – approx. 30 min before PACU)
  • Lidocaine 1.5 mcg/kg/hr (if no liposomal bupivicaine)
  • Dexamethasone 10mg IV x 1
  • Liposomal bupivacaine injection into the appropriate area (mixture LAB 1.3% 20 mL + 0.5% Bupiv 30 mL + NS 20 mL) 2/3 injected sub fascia, 1/3 injected supra fascia

Post-op:

  • Ketorolac 30 mg IV q6h x 48 hours
  • Celebrex 200 mg po bid x 5 days
  • Acetaminophen 1000 mg q6h x 5 days
  • Gabapentin 300 mg po bid x 5 days (may increase if neuropathic pain present)
  • Ketamine 0.1-0.2 mg/kg/hr x 1-3 days
  • +/- Lidocaine 1.5 mg/kg/hr up to 8 hours after induction (only consider if no liposomal bupivicaine used in OR)
  • Oxycodone 1 tab q4h PRN mod – severe pain

Early results of these adjustments are promising, but more rigorous scientific studies are needed to confirm our initial results.

References

  1. Alam A, Gomes T, Zheng H, et al. Long-term analgesic use after low-risk surgery; a retrospective cohort study. 2012; 172(5):425-430.
  2. Carroll I, Barelka P, Wang CKM, et al. A pilot cohort study of the determinants of longitudinal opioid use after surgery. Anesth Analg. 2012; 115(3):694-702.
  3. Kessler ER, Shah M, Gruschkus SK, et al. Cost and quality implications of opioid-based postsurgical pain control using administrative claims data from a large health system. Pharmocotherapy. 2013; 33(4):383-391.
  4. Shafi S, Collinsworth AW, Copeland LA, et al. Association of opioid-related adverse drug events with clinical and cost outcomes among surgical patients in a large integrated health care delivery system.  JAMA Surg. 2018; 153(8):757-763.
  5. Fletcher D, Martinez V. Opioid-induced hyperalgesia in patients after surgery: a systematic review and a meta-analysis. British Journal of Anaesthesia. 112(6): 991-1004 (2014).
  6. Hwang W, Lee J, Park J, Joo J. Dexmedetomidine vs remifentanil in postoperative pain control after spine surgery: a randomized controlled study. BMC Anesthesiology. (2015) 15:21.
  7. Murphy GS, Szokol J. Intraoperative Methadone in Surgical Patients. Intraoperative Methadone in Surgical Patients. 2019; 131:678–92.
  8. Murphy GS, Avram MJ, et al. Postoperative Pain and Analgesic Requirements in the First Year after Intraoperative Methdone for Complex Spine and Cardiac Surgery. Anesthesiology. 2020; 132:330–42.
  9. Pendi A, Field R, et al. Perioperative Ketamine for Analgesia in Spine Surgery: A meta analysis of Randomized Controlled Trials. Spine. 2018 Mar 1; 43(5):E299–E307.
  10. Farag E, Ghobrial M, et al. Effect of Perioperative Intravenous Lidocaine Adminstration on Pain, Opioid Consumption, and Quality of Life after Complex Spine Surgery. Anesthesiology 2013; 119:932–940.
  11. Ingersoll-Weng E, Greene A, et al. Review of Dexmedetomidine. American Society of Regional and Pain Medicine News. Aug 2018 Issue.
  12. Lee Y, Ming L, et al. Effects of Dexmedetomidine on motor- and somatosensory- evoked potentials in patients with thoracic spinal cord tumor: a randomized contolled trial. BMC Anesthesiol 2016; 16: 51.
  13. Rozet I, Metzner J, et al. Dexmedetomidine Does Not Affect Evoked Potentials During Spine Surgery. Anesthesia & Analgesia. August 2015. 121 (2). 492–501.
  14. Tobias JD, Goble TJ, Bates G, Anderson JT, Hoernschemeyer DG. Effects of dexmedetomidine on intraoperative motor and somatosensory evoked potential monitoring during spinal surgery in adolescents. Pediatric Anaesth. 2008;18(11):1082–1088.
  15. Sivaganesan A, Chotai S, et al. The effect of NSAIDs on spinal fusion: a cross-disciplinary review of biochemical, animal, and human studies. Eur Spine J. (2017) 26: 2719–2728.

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