The effect of cerebral palsy on the action of vecuronium with or without anticonvulsants

Resistance to Neuromuscular Blockade by Rocuronium in Surgical Patients with Spastic Cerebral Palsy

Individuals with spastic cerebral palsy (CP) often exhibit altered sensitivities to neuromuscular blocking agents (NMBAs) used for surgical intubation. We assessed usage of the NMBA rocuronium in patients with spastic CP and evaluated potential modifiers of dosing including gross motor function classification system (GMFCS) level, birthweight, gestational age, and the use of anticonvulsant therapy. In a case-control study, surgical patients with spastic CP (n = 64) or with idiopathic or non-neuromuscular conditions (n = 73) were enrolled after informed consent/assent. Patient data, GMFCS level, anticonvulsant use, and rocuronium dosing for intubation and post-intubation neuromuscular blockade were obtained from medical records. Findings reveal participants with CP required more rocuronium per body weight for intubation than controls (1.00 ± 0.08 versus 0.64 ± 0.03 mg/kg; p < 0.0001). Dosing increased with GMFCS level (Spearman's rho = 0.323; p = 0.005), and participants with moderate to severe disability (GMFCS III-V) had elevated rocuronium with (1.21 ± 0.13 mg/kg) or without (0.86 ± 0.09 mg/kg) concurrent anticonvulsant therapy. Children born full-term or with birthweight >2.5 kg in the CP cohort required more rocuronium than preterm and low birthweight counterparts. Individuals with CP exhibited highly varied and significant resistance to neuromuscular blockade with rocuronium that was related to GMFCS and gestational age and weight at birth.

Major surgical procedures in children with cerebral palsy

There are 3 surgical procedures that patients with cerebral palsy (CP) undergo that may be considered major procedures: femoral osteotomies combined with pelvic osteotomies, spine fusion, and intrathecal baclofen pump implant for the treatment of spasticity. Many complications are known to occur at a higher rate in this population, and some may be avoided with prior awareness of the preoperative pathophysiology of the patient with CP.

Disruption of basal lamina components in neuromotor synapses of children with spastic quadriplegic cerebral palsy

Cerebral palsy (CP) is a static encephalopathy occurring when a lesion to the developing brain results in disordered movement and posture. Patients present with sometimes overlapping spastic, athetoid/dyskinetic, and ataxic symptoms. Spastic CP, which is characterized by stiff muscles, weakness, and poor motor control, accounts for ∼80% of cases. The detailed mechanisms leading to disordered movement in spastic CP are not completely understood, but clinical experience and recent studies suggest involvement of peripheral motor synapses. For example, it is recognized that CP patients have altered sensitivities to drugs that target neuromuscular junctions (NMJs), and protein localization studies suggest that NMJ microanatomy is disrupted in CP. Since CP originates during maturation, we hypothesized that NMJ disruption in spastic CP is associated with retention of an immature neuromotor phenotype later in life. Scoliosis patients with spastic CP or idiopathic disease were enrolled in a prospective, partially-blinded study to evaluate NMJ organization and neuromotor maturation. The localization of synaptic acetylcholine esterase (AChE) relative to postsynaptic acetylcholine receptor (AChR), synaptic laminin β2, and presynaptic vesicle protein 2 (SV2) appeared mismatched in the CP samples; whereas, no significant disruption was found between AChR and SV2. These data suggest that pre- and postsynaptic NMJ components in CP children were appropriately distributed even though AChE and laminin β2 within the synaptic basal lamina appeared disrupted. Follow up electron microscopy indicated that NMJs from CP patients appeared generally mature and similar to controls with some differences present, including deeper postsynaptic folds and reduced presynaptic mitochondria. Analysis of maturational markers, including myosin, syntrophin, myogenin, and AChR subunit expression, and telomere lengths, all indicated similar levels of motor maturation in the two groups. Thus, NMJ disruption in CP was found to principally involve components of the synaptic basal lamina and subtle ultra-structural modifications but appeared unrelated to neuromotor maturational status.

C Histomorphology of neuromuscular junction in Duchenne muscular dystrophy

BACKGROUND

Our objective was to better understand neuromuscular junction (NMJ) morphology in children with Duchenne muscular dystrophy (DMD).

METHODS

We examined the NMJs of four children, age 6-13 years, who were diagnosed with DMD. Using our previously established staining technique, we examined the gross appearance of the NMJs in patients with DMD and evaluated the spread of acetylcholine receptors (AChRs) in relationship to the NMJs. We used a computerized algorithm to measure the area of staining corresponding to AChRs and NMJ.

RESULTS

Abnormal shape and morphological appearance of some of the NMJs was clearly evident. The spread of AChRs in DMD patients is comparable with the spread of AChRs in nonDMD patients.

CONCLUSIONS

The distribution of AChRs in relationship to the boundaries of NMJs in DMD children is similar to the distribution of NMJs in the erector spinae muscles of idiopathic scoliosis patients.

Surgery and anesthesia for children who have cerebral palsy

Cerebral palsy is a spectrum of signs and symptoms resulting from an injury to the brain during its developmental stage. Children with cerebral palsy have disorders that impact their anesthetic management. In particular, abnormalities of the respiratory system, gastrointestinal system, and neuromuscular system must be considered. There is emerging evidence for abnormalities in their neuromuscular junction that potentially increase their anesthetic risk. In addition, there are recent data explaining possible reasons for increased bleeding in these children.

Dysmorphic neuromuscular junctions associated with motor ability in cerebral palsy

Cerebral palsy (CP) is the most prevalent neurologic disease in children and a leading cause of severe physical disability. Research and clinical experience indicate that children with CP have abnormal neuromuscular junctions (NMJs), and we present evidence that nonapposition of neuromuscular junction components is associated with the severity of motor system deficit in CP. Leg muscle biopsies collected from ambulatory (n = 21) or nonambulatory (n = 38) CP patients were stained in order to detect acetylcholine receptor (AChR) and acetylcholine esterase (AChE). Image analysis was used to calculate the extra-AChE spread (EAS) of AChR staining to estimate the amount of AChR occurring outside the functional, AChE-delimited NMJ. Nonambulatory children exhibited higher average EAS (P = 0.025) and had a greater proportion of their NMJs with significantly elevated EAS (P = 0.023) than ambulatory children. These results indicate that physical disability in children with CP is associated with structurally dysmorphic NMJs, which has important implications for the management of CP patients, especially during surgery and anesthesia.

Resistance to vecuronium in a term neonate

We report a case of resistance to curarization in a term neonate undergoing surgery. The dosage of vecuronium required to obtain satisfactory muscular blockade and cessation of spontaneous breathing efforts was more than 10-fold the normal one. The operation was delayed for 90 min The mechanism of this marked resistance is unknown, but some possible hypotheses are presented, focusing on the neonate's poor intrauterine growth and an abnormality in pharmacodynamics.