Laparoscopic fundoplication under general anesthesia in a child with spinal muscular atrophy type II: a case report

Abstract

Background

Spinal muscular atrophy (SMA) linked to chromosome 5q demonstrates an autosomal recessive inheritance pattern. SMA is characterized by diffuse, symmetric, proximal muscle weakness, with lower limb predominance in the lower limbs than in the upper limbs, and by absent or markedly diminished deep tendon reflexes. The disease incidence ranges 0.005–0.013% among live births. Pediatric anesthesia management in SMA remains scarcely documented. There are scarcely documented of anesthesia management in patients with SMA, particularly among children and adolescents. Given the generalized muscle atrophy in these patients, anesthesiologists are often cautious about administering general anesthesia with neuromuscular blocking agents (NMBAs). Consequently, many anesthesiologists have explored alternative anesthetic techniques that avoid the use of NMBAs while ensuring that there is no interference with the surgical procedure. Particularly for laparoscopic procedures, which require a certain degree of muscle relaxation, the use of NMBAs remains underreported, with no relevant cases documented in pediatric patients.

Case presentation

We report the successful administration of general anesthesia in a child with SMA type II at our institution, in which an NMBA was used and the child was uneventful extubation without associated respiratory complications.

Conclusions

Pediatric patients with SMA may experience unexpected airway difficulties, necessitate careful preparation and consideration of awake intubation. NMBAs should be used cautiously, while nondepolarizing NMBAs and sugammadex demonstrate clinical viability. The benefits of fast-track anesthesia warrant further study, and anesthetic plans should be tailored on the basis of a thorough assessment of the patient’s condition.

Background

Spinal muscular atrophy (SMA), an autosomal recessive disorder arising from SMN1 gene mutations/deletions on chromosome 5q, results in SMN1 protein deficiency causing progressive proximal muscle weakness and atrophy. SMA is stratified into four subtypes based on genetic expression profiles. Type II (Dubowitz disease), representing 20% of cases, typically manifests between 3 and 15 months [1]. Given that atrophy of the proximal muscles can lead to developmental abnormalities, such as thoracic deformities and scoliosis, the risk associated with perioperative is significantly increased. Affected children typically achieve independent sitting/standing capacity, though with delayed milestone attainment compared to neurotypical peers. Muscle weakness in type II SMA is predominantly observed in proximal muscles, with greater severity in the lower limbs than in the upper limbs. The most common clinical manifestations include unaffected facial and eye muscles, tongue muscle atrophy accompanied by fasciculations, areflexia, tremor-like myoclonus involving the distal limbs, dysphagia, and respiratory insufficiency. Universal progression to scoliosis, compounded by respiratory muscle weakness, culminates in restrictive lung pathology. The ability to sit and stand independently is generally lost during adolescence. In terms of life expectancy, reports indicate that approximately 2/3 of patients with type II SMA survive to the age of 25 years [2].

Children with SMA often require multiple anesthetic or surgical procedures throughout their lifetime. These procedures may include scoliosis orthomorphia and gastrostomy, among others [3]. The prognosis depends on the extent and duration of respiratory complications. In the anesthesia plan for such patients, airway management and muscle relaxant administration are both critical and challenging aspects. To date, there are no established guidelines for anesthesia in patients with SMA, and such interventions in the pediatric population are even more uncommon. With the continuous advancement of NMBAs and their antagonists, as well as the evolving diversity in airway management, we are able to develop rational anesthesia drug regimens and management strategies tailored to the specific characteristics of different cases in anesthetic practice. Recently, we successfully administered surgical anesthesia to a child with type II SMA who underwent laparoscopic fundoplication, resulting in the patient discharge from the ward following successful extubation. We report our management experience below.

Case presentation

A 14-year-old male (height 165 cm, weight 33.5 kg) presented with chronic gastroesophageal reflux refractory to two-year medical management. Laparoscopic fundoplication under general anesthesia was subsequently elected. The child exhibited lower limb weakness at 8–9 months and could not stand unaided. At the age of 1 year, the child underwent a genetic examination, which revealed a pure deletion of exons 7 and 8 of the SMN1 gene, establishing SMA type II diagnosis. Progressive motor function decline persisted despite structured neurorehabilitation protocols. Confined to a wheelchair, he was unable to move his lower limbs, could sit and stand with assistance, grasped objects with his upper limbs, and had difficulty moving his head. His intellectual development remained within the normal range. From 2021 to the present, he has received CT-guided intrathecal injections of nusinersen, and since 2023, oral Risdiplam, with no subsequent muscle strength deterioration.

Physical examination demonstrated severe thoracolumbar scoliosis manifesting as left convex curvature (apex at T12) with Cobb angle measuring 93°. The thoracolumbar spine was prominently visible with a pronounced posterior projection, and the remaining spinal curvature was accompanied by a pelvic obliquity. (Fig. 1)

Fig. 1.

Preoperative standing whole-spine radiography demonstrated left convex thoracolumbar scoliosis (apex at T12) with Cobb angle measuring 93°, accompanied by rotational kyphotic deformity

Preoperative examination

We conducted a thorough preoperative examination and assessment of the patient, which served as the basis for formulating our intraoperative anesthesia management strategy. Despite severe spinal curvature and head-lifting weakness, the patient had no anatomical abnormalities in the head and neck region. The trachea was centrally positioned, with normal mouth opening, and mentum-to-hyoid distance. The patient was classified as Mallampati grade III, had no loose teeth, but exhibited weakened sputum expectoration and swallowing abilities. The SARI score was 3 (with a score of ≥ 4 indicating difficult direct laryngoscopy) [4]. Lung auscultation revealed no abnormalities. Pulmonary function tests revealed mixed ventilatory dysfunction, marked by severe restriction and moderate obstruction. The patient demonstrated increased muscle tone, with muscle strength rated as grade 4 in the upper limbs and grade 2 in the lower limbs. The upper gastrointestinal imaging results indicated a sliding esophageal hiatal hernia (Fig. 2). The remaining preoperative examination revealed no significant abnormalities.

Fig. 2.

Preoperative gastrointestinal (GI) tract: the esophagogastric ring (B-ring) was located above the diaphragm, and multiple instances of gastroesophageal reflux were observed, reaching the level of T1 level vertebra during the examination

Preoperative preparation

In addition to standard preoperative equipment and medications, we meticulously prepared advanced airway management devices including a video laryngoscope, lightwand, and fiberoptic bronchoscope (FOB) in accordance with difficult airway protocols, with concurrent activation of the difficult airway response team. Given the patient’s elevated aspiration risk, the laryngeal mask airway was intentionally excluded from the contingency plan.

Considerable deliberation occurred regarding the optimal intubation strategy. While awake FOB intubation was proposed to maximize airway security, this approach was ultimately deemed impractical due to the child’s profound preoperative anxiety and explicit refusal to cooperate despite comprehensive counseling with both the patient and guardians. After thorough risk-benefit analysis and with respect for the patient’s autonomy, we elected to perform tracheal intubation under spontaneous ventilation. The implemented protocol involved FOB-guided intubation following loss of consciousness while preserving respiratory drive through avoidance of NMBAs. A rescue strategy was established: if initial intubation attempts failed but facemask ventilation remained effective, rapid sequence induction with rocuronium would be initiated, with immediate availability of its selective reversal agent sugammadex.

Intraoperative procedure

The anesthetic procedure involved the intravenous administration of midazolam (2 mg), esketamine (1 mg/kg), atropine (0.3 mg), propofol (2 mg/kg), and dexamethasone (5 mg). These agents were administered for anesthetic induction to preserve the child’s spontaneous breathing. During the intubation procedure, the child exhibited high muscle tone, which complicated laryngoscope placement. Additionally, prolonged exposure of the oral mucosa to gastric juice resulted in increased bleeding and secretions in the oral cavity. This issue resulted in obstructed vision and unexpected difficulties with intubation. Following unsuccessful FOB intubation, 0.6 mg/kg rocuronium bromide was administered after confirming adequate mask ventilation to facilitate tracheal intubation. After achieving jaw muscle relaxation, the endotracheal tube was smoothly inserted through laryngoscopy. Capnography was 2utilized to monitor end-tidal CO₂ intraoperatively, and respiratory parameters were actively adjusted to maintain an arterial CO₂ pressure (PaCO₂) between 35 and 45 mmHg. The left radial artery was cannulated for continuous arterial pressure monitoring, and cannulation was also performed in the right internal jugular vein. Narcotrend monitoring was employed to monitor the depth of anesthesia during surgery. For intraoperative anesthetic maintenance, dexmedetomidine at 0.5 µg/kg/h, remifentanil at 0.15 µg/kg/min, and 2% sevoflurane were administered via inhalation. Warm air blankets were utilized, and the fluids were heated and infused to maintain the child’s body temperature at or above 36 °C. During the procedure, a pneumoperitoneum pressure of 11 mmHg and a gas flow rate of 10 L/min were maintained to optimize surgical field visualization. Nissen fundoplication was performed with a total duration of 60 min (45 min pneumoperitoneum time). Intraoperative parameters remained stable: blood loss 20 mL, 1000 mL balanced electrolyte solution infused, urine output 250 mL. Considering the potential for long-acting opioid analgesics to hinder a patient’s respiratory recovery, a strategy of local anesthetic infiltration at the surgical site, combined with intravenous NSAIDs, was utilized to manage postoperative pain. Following surgery, sugammadex at a dose of 2 mg/kg was administered to counteract residual rocuronium effects. Within 5 min, spontaneous respiration resumed, and extubation of the tracheal tube was performed upon the patient’s awakening at a Narcotrend index of approximately 90, with the patient being able to open his eyes upon command, tidal volume > 6 mL/kg, respiratory rate < 30 breaths/min. Following extubation, the patient was observed for 20 min, during which oxygen saturation (SpO₂) remained ≥ 95% without supplemental oxygen. The patient was subsequently transferred back to the ward for continuous monitoring over 2 h. Postoperatively, there were no clinical signs of pulmonary complications, and follow-up chest X-rays and inflammatory markers, including complete blood count, remained within normal limits. The patient achieved full recovery and was discharged on postoperative day 7.

Discussions

Recurrent pneumonia resulting from reflux aspiration poses a significant threat to the child’s life expectancy. After careful consideration of the risks and potential benefits, the family opted for surgical intervention to enhance the child’s quality of life. However the family’s significant concerns regarding potential endotracheal intubation-related complications—including ventilator dependence and aspiration risks—laparoscopic surgery inherently elevates intra-abdominal pressure, significantly amplifying the risk of gastroesophageal reflux with subsequent pulmonary aspiration. To ensure the effectiveness and safety of airway management during anesthesia, tracheal intubation and general anesthesia were ultimately selected for this case.

Experience with general anesthesia in patients with type II SMA is scarce. Most reported cases involve procedures such as cesarean section, correction of thoracolumbar deformity, gastrostomy, and fracture repair [5–8]. The aforementioned procedures do not necessitate the use of high doses of NMBAs and can often be performed via alternative anesthetic techniques, such as local nerve blockade. According to existing case reports, tracheal intubation without neuromuscular blockade appears to be more commonly used in this patient population. There has been a single report of a 62-year-old woman who underwent laparoscopic cholecystectomy without any NMBAs [9]. In this case, the patient’s muscle function was severely impaired, with movement limited to one finger, indicating that her abdominal muscles were weak enough to allow adequate pneumoperitoneum without muscle relaxation. However, there have been no analogous case reports involving children. This case is unique in that the child has been receiving regular SMA-targeted therapy without further muscle deterioration. In this case, omitting muscle relaxants may compromise surgical exposure and precision, potentially extending both surgery and anesthesia duration. Therefore, the use of muscle relaxants should be carefully considered.

A reported high incidence of difficult airway access exists in patients with SMA [10]. Even when preoperative physical examinations of the airway indicate near-normal conditions, patients with SMA are still susceptible to unexpected difficulties with airway access postanesthesia induction due to the possible presence of joint contractures and mandibular ankylosis. In this case, unexpected challenges with intubation arose due to increased oral secretions and mandibular ankylosis. Consequently, it is imperative to prepare for the possibility of a difficult airway in SMA patients requiring general anesthesia intubation. For cooperative patients, awake transnasal or transcricoid orotracheal intubation is preferable.

Regarding the choice of anesthetic drugs, we selected agents that had been previously administered to similar patients without serious complications [3]. The use of NMBAs in these patients remains controversial, primarily owing to reduced expression of the survival motor neuron (SMN) protein, resulting from mutations in the SMN gene on chromosome 5. A decrease in the SMN not only leads to muscle atrophy and weakness in the extremities, trunk, and respiratory muscles but also induces dysfunction and degeneration of α motor neurons in the spinal cord and brainstem. Within neurons, the SMN is present in axonal granules to facilitate the rapid bidirectional transport of neurotransmitters [11]. Both depolarizing and nondepolarizing NMBAs act on postsynaptic membrane receptors to produce muscle relaxation; however, a lack of SMN expression can impair the rapid transport of acetylcholine and extend the metabolism of these drugs. Currently, the use of NMBAs, particularly depolarizing NMBAs is unrecommended. Studies indicate that depolarizing NMBAs (e.g., succinylcholine) may induce life-threatening rhabdomyolysis and hyperkalemia [12]. Additionally, non-depolarizing NMBAs demonstrate prolonged pharmacodynamic effects in SMA patients, with documented cases of residual neuromuscular weakness persisting for > 24 h postoperatively despite standard-dose reversal with antagonists [13]. Notably, the existing literature presents conflicting observations: some case reports describe without related complications after the use of depolarizing or nondepolarizing muscle blockers has been reported [11]. Additionally, conventional neuromuscular monitoring (e.g., train-of-four at the adductor pollicis) demonstrates limited reliability in SMA due to progressive atrophy of peripheral musculature, rendering objective quantification of neuromuscular recovery unfeasible in most of cases [14]. Consequently, the risks of undetected residual paralysis and reintubation outweigh the potential benefits, reinforcing the consensus to avoid routine NMBA use in this population.

Sugammadex sodium, a drug that specifically and noncovalently binds to NMBAs such as rocuronium to reverse their neuromuscular effects, offers another layer of protection for patients requiring the use of NMBAs. The unique mechanism of sugammadex, which specifically binds to steroidal neuromuscular blocking agents, makes it a more suitable choice for this patient population compared to neostigmine, which reverses neuromuscular blockade by increasing acetylcholine levels at the neuromuscular junction. Reports indicate that the muscle-relaxant effect of rocuronium has been successfully reversed with no related side effects in SMA patients after sugammadex sodium administration [15]. In this case, spontaneous respiration was restored within 5 min postoperation with the administration of sugammadex sodium, and the tidal volume and respiratory frequency reached over 80% of the preoperative values. Extubation was successfully accomplished, with no respiratory inhibition or weakness observed within 30 min. The child was successfully extubated without delayed extubation or weaning failure, which may be attributed to preserved preoperative cardiopulmonary function, consistent administration of disease-modifying agents (e.g., Nusinersen), and timely intraoperative administration of specific reversal agents.

Prolonged mechanical ventilation elevates risks of ventilator dependence, ventilator-associated lung injury, respiratory infections, tracheal stenosis, and vocal cord paralysis. In SMA patients, progressive atrophy of proximal respiratory musculature (diaphragm and intercostal muscles) exacerbates ventilator weaning challenges. Extended ventilation duration correlates with prolonged hospitalization, delayed functional recovery, and increased socioeconomic burdens on patients/families. Thus, a fast-track anesthesia protocol with early extubation strategies and optimized perioperative management is recommended for this population.

Conclusions

It can be concluded from this case that (a) Despite normal preoperative airway assessment, SMA patients may still face risks of ventilation or intubation difficulties. A difficult airway management plan should be followed for all SMA patients, with awake intubation and preserved spontaneous respiration recommended to address potential intubation challenges. (b) The use of NMBAs with caution in patients with SMA is recommended. However, the successful use of non-depolarizing NMBAs and their specific antagonist, sugammadex, can provide insights into the future anesthetic management of such patients. (c) Regular use of disease-specific medications (e.g., oral Risdiplam) could improve perioperative safety and may help reduce hospitalization duration in patients. (d) The effectiveness of fast-track anesthesia in reducing complication risks, shortening ICU stays, and decreasing hospitalization duration requires further verification through additional clinical studies. Anesthetic management of patients with SMA requires a thorough assessment of the patient’s disease stage, degree of muscle atrophy, and current treatment to tailor an individualized anesthetic plan.

Abbreviations

SMA

Spinal muscular atrophy

NMBAs

Neuromuscular blocking agents

FOB

Fiberoptic bronchoscope

SMN1

Survival of Motor Neuron 1, Telomeric

CT

Computed tomography

GI

Gastrointestinal

ICU

Intensive care unit

Authors’ contributions

Yang LF collected the medical records of the participants and drafted the initial manuscript. Yi ZG took responsibility for the investigation and data curation. All the authors were involved in clinical care, reviewed and revised the manuscript, approved the final manuscript as submitted and agreed to be accountable for all aspects of the work.

Funding

No funding.

Data availability

No datasets were generated or analysed during the current study.

Declarations

Ethics approval and consent to participate

Not applicable.

Consent for publication

Both parents of the patient described have signed the consent form for publication, which is available for review by the Editor of this journal.

Competing interests

The authors declare no competing interests.