Surgery is frequently needed for both diagnostic and treatment purposes in patients with neuromuscular disorders like spinal muscular atrophy (SMA).1 Optimizing perioperative care in these patients requires a multidisciplinary team that can collaborate to anticipate and prevent complications and reduce associated morbidity and mortality.2 Perioperative risk is higher in patients with SMA and other diseases that affect the central nervous system,3 and experts suggest that these risks need to be discussed with patients prior to surgery.4 In addition, a full preoperative evaluation of these risks is suggested as a means for improving outcomes.
Operative Risks in SMA
Neuromuscular disorders increase certain risks associated with operations. For instance, research on patients with neuromuscular disorders has found that these patients are more prone than others to experience infections at their surgical sites. Postoperative infections occur at a rate of 13.1 percent in this population of patients.5 Respiratory failure is one of the greatest risks associated with operations in those with neuromuscular disorders and can lead to the need for long-term ventilation. Because moderate and severe forms of neuromuscular disorders often involve diaphragm weakness, spinal deformity, dysphagia, and frequent aspiration, the respiratory system tends to be compromised.1
One of the things that makes SMA and other neuromuscular disorder patients vulnerable during and after operations is being suggested to anesthetic drugs. Indeed, anesthetic agents have unique effects on those with neuromuscular disorders, including on their pulmonary functions,1 and those with neuromuscular disorders often experience postoperative complications related to the use of anesthetics.4 Given the risks of general anesthesia, local anesthesia and spinal anesthesia tend to be the preferred methods of anesthesia in patients with neuromuscular disorders.6 6
The use of general anesthesia in neuromuscular disorders is difficult because SMA patients can be hypersensitive to neuromuscular blocking agents and can experience succinylcholine-induced hyperkalemia.7 Succinylcholine can further destabilize the already-weak muscles in those with neuromuscular disorders. Resulting hyperkalemia has caused sudden cardiac arrest in some cases.8
The use of general anesthesia in neuromuscular disorders is difficult because SMA patients can be hypersensitive to neuromuscular blocking agents and can experience succinylcholine-induced hyperkalemia.7 Succinylcholine can further destabilize the already-weak muscles in those with neuromuscular disorders. Resulting hyperkalemia has caused sudden cardiac arrest in some cases.8
Reducing Anesthesia-Related Risks
Luckily, there has been significant research into how to safely use anesthesia in SMA patients, with several successes reported. For instance, dental treatment has been enabled in SMA patients with the use of anesthesia of the temporomandibular joint,6 and SMA type 3 patients have undergone successful Cesarean sections with epidural anesthesia.9 Sugammadex has also proven safe in several case studies of those with neuromuscular disorders.4
Another study has found that a combination of nondepolarizing muscle relaxants and target-controlled infusion of remifentanil and propofol can provide effective anesthesia in SMA type 4 patients.10 However, propofol, which is an anesthetic agent that is emulsified with a long-chain fatty acid carrier, has also been shown to lead to significant complications in patients with fatty acid oxidation disorders.11 This information is relevant for those with SMA, as SMA is associated with abnormal fatty acid oxidation.12
Standards for Perioperative Care
Though the anesthesia-related risks associated with neuromuscular disorders is increasing, experts argue that multidisciplinary guidance for standardizing perioperative care in patients with neuromuscular disorders is needed.1,13,14 Protocols are needed not just for the specific strategies for anesthesia during operations but standards are also needed at the preoperative, intraoperative, and postoperative timeframes.
Preoperatively, researchers suggest that a multidisciplinary team should be coordinated and risk stratification should be conducted in those with moderate or severe disease. Evaluating aspiration risk, cardiac status, and sleep should all be a part of the preoperative process, and any existing pulmonary infections should be treated.
During operations, succinylcholine and non-depolarizing neuromuscular blockers should be avoided when possible, and temperature should be closely monitored.1 Following surgery, continuous pulse oximetry should be employed for at least 24 hours, heart status should be monitored through echocardiography, and pain should be controlled through acetaminophen, regional anesthesia, low-dose opioids. Other medications can also be used in the management of pain if they are not contraindicated.
References
1. Kynes JM, Blakely M, Furman K, Burnette WB, Modes KB. Multidisciplinary Perioperative Care for Children with Neuromuscular Disorders. Child (Basel, Switzerland). 2018;5(9). doi:10.3390/children5090126
2. Boivin A, Antonelli R, Sethna NF. Perioperative management of gastrostomy tube placement in Duchenne muscular dystrophy adolescent and young adult patients: A role for a perioperative surgical home. Paediatr Anaesth. 2018;28(2):127-133. doi:10.1111/pan.13295
3. Hachenberg T, Schneemilch C. Anesthesia in neurologic and psychiatric diseases: is there a “best anesthesia” for certain diseases? Curr Opin Anaesthesiol. 2014;27(4):394-402. doi:10.1097/ACO.0000000000000098
4. Katz JA, Murphy GS. Anesthetic consideration for neuromuscular diseases. Curr Opin Anaesthesiol. 2017;30(3):435-440. doi:10.1097/ACO.0000000000000466
5. Brooks JT, Sponseller PD. What’s new in the management of neuromuscular scoliosis. J Pediatr Orthop. 2016;36(6):627-633. doi:10.1097/BPO.0000000000000497
6. Chi SI, Kim HJ, Seo K-S, Lee JH, Chang J. Local anesthesia of the temporomandibular joint to reduce pain during mouth opening for dental treatment in a patient with spinal muscular atrophy. J Dent Anesth pain Med. 2016;16(2):137-140. doi:10.17245/jdapm.2016.16.2.137
7. Kim SJ, Kim EJ, Min BW, Ban JS, Lee SG, Lee JH. Epidural anesthesia for the patient with type IV spinal muscular atrophy -A case report-. Korean J Anesthesiol. 2010;59 Suppl:S65-8. doi:10.4097/kjae.2010.59.S.S65
8. Rosenberg H, Pollock N, Schiemann A, Bulger T, Stowell K. Malignant hyperthermia: a review. Orphanet J Rare Dis. 2015;10:93. doi:10.1186/s13023-015-0310-1
9. Gaca M, Kokot N, Koziolek A, Kuczkowski KM. Combined spinal epidural anesthesia for cesarean section in a parturient with spinal muscle atrophy type III (Kugelberg-Walendar disease). J Matern Fetal Neonatal Med. 2011;24(1):195. doi:10.3109/14767058.2010.482617
10. Liu X-F, Wang D-X, Ma D. Using general anesthesia plus muscle relaxant in a patient with spinal muscular atrophy type IV: A case report. Case Rep Anesthesiol. 2011;2011:743587. doi:10.1155/2011/743587
11. Rigoulet M, Devin A, Averet N, Vandais B, Guerin B. Mechanisms of inhibition and uncoupling of respiration in isolated rat liver mitochondria by the general anesthetic 2,6-diisopropylphenol. Eur J Biochem. 1996;241(1):280-285.
12. Tein I, Sloane AE, Donner EJ, Lehotay DC, Millington DS, Kelley RI. Fatty acid oxidation abnormalities in childhood-onset spinal muscular atrophy: primary or secondary defect(s)? Pediatr Neurol. 1995;12(1):21-30.
13. Racca F, Mongini T, Wolfler A, et al. Recommendations for anesthesia and perioperative management of patients with neuromuscular disorders. Minerva Anestesiol. 2013;79(4):419-433.
14. Brandom BW, Veyckemans F. Neuromuscular diseases in children: a practical approach. Paediatr Anaesth. 2013;23(9):765-769. doi:10.1111/pan.12246