Conference Lectures

Anaesthetic considerations in children with cerebral palsy
Dr S Bala Bhaskar
Children with cerebral palsy
Cerebral palsy (CP) is a heterogeneous group of disorder characterised by permanent chronic motor disorder leading to movement and posture disturbances due to non progressive defects in the early developmental stages of brain. The magnitude of the problem can be understood from the fact it affects nearly 2-2.5 child /1000 live birth in developed countries. The primary muscle dysfunction causes a host of secondary conditions many of which require surgical correction. Motor dysfunction also affects GI and respiratory system. These along with associated neurological impairment have implications in perioperative period. Hence knowledge about this condition is essential for anaesthesiologist while providing care for these patients.
Etiopathogenesis of cerebral palsy:
As previously thought cerebral palsy is not commonly due to birth asphyxia but rather is causative factor in 10% of affected population. Brain damage/defect can happen during antenatal, perinatal and postnatal period. While preterm and low birth weight are risk factors for CP, term children do suffer CP. Periventricular leucomalacia (PVL) and intraventricular haemorrhage(IVH) are commonly associated pathophysiologic changes in patients with CP. Involvement of corticospinal tract (Pyramidal tract) with Upper Motor Neurone (UMN) lesion causes spastic CP (nearly 80% cases). Involvement of cerebellum, basal ganglia and thalamus leads to dyskinetic, dystonic and ataxic CP (20% cases). Sometimes mixed pattern is seen. The disease can involve any group of muscles like limb, trunk etc. Involvement of muscles in mouth, tongue and pharynx is described as Oral motor dysfunction or oropharyngeal dysfunction. Topographical limb involvement can be monoplegia, diplegia and quadriplegia. Palisano R et al proposed Gross Motor Function Classification System (GMFCS) based on both disability and functional limitation present on day today activities of children at various ages.(1) Detailed discussion about etiopathogenesis and various classification is beyond scope of this article and has been presented elsewhere.(2-4)
Secondary effect and Associated problem:
Cerebral palsy is essentially a movement and posture disorder. The secondary effect of the motor system involvement causes varying degree of musculoskeletal deformities. Oral motor dysfunction leads to dental, GI and respiratory system disorders. Associated with this motor disorder is a list of other neurological problem to various extents in particular patient. Severe form of motor involvement like quadriplegia is generally accompanied by severe neurological symptoms and oral motor dysfunction. Also quadriplegic patients commonly have trunk muscle involvement leading to scoliosis. List of these problems are given in table 1.

Table 1: Systems involved in cerebral palsy


CNS

GIT and RS

Musculoskeletal

Urinary tract
  1. Seizures
  2. Cognitive and intellectual impairment
  3. Hearing and speech impairment
  4. Visual defects

 
  1. Dental caries
  2. Malocclusion
  3. Drooling
  4. Swallowing difficulty
  5. Esophagitis
  6. Stricture esophagus
  7. GERD
  8. Recurrent pulmonary aspiration
  1. Flexion deformities
  2. Scissoring of gait
  3. Tip toeing
  4. Hip dislocation
  5. Scoliosis
  1. Urinary incontinence
  2. Urinary urgency

 

Table 2: List of surgical conditions commonly associated with cerebral palsy


Orthopaedics/Neuro

GIT

Dental

Others
  1. Tenotomy
  2. Soft tissue  release
  3. Osteotomies
  4. Tendon transfer procedures
  5. Scoliosis correction
  6. Selective dorsal rhizotomy
  1. Fundoplication
  2. Gastrostomy
  3. Esophageal dilatation
  1. TMJ contracture release
  2. Teeth extraction and restoration

 
  1. Inguinal hernia in preterm child
  2. Grommet insertion
  3. Diagnostic procedures/   imaging
  4. Botulinium toxin injection
  5. Infusion device insertion

 

Perioperative management:
As described from earlier sections it is prudent to assume a child with CP presents for surgery more common than normal children. The child with severe CP may come for multiple surgeries. Some of commonly performed surgeries are given in table 2.
Preoperative evaluation:
The degree of associated cognitive, communicative problem and mental retardation makes preoperative history taking a difficult task. Presence of care takers is of immense value as they can give complete medical history and help establishing rapport and confidence between the anaesthetist and patient. Establishing confidence is important as this will reduce the level of separation anxiety when these patients are taken inside the operation theatre or diagnostic suites. The history taking should focus on associated conditions like GERD, seizures, etc. Night awakening in cerebral palsy is an indication of GERD.  Medication history should be specifically sought for. Though cerebral palsy as such does not affect organs like liver and renal system, any coexisting diseases should be enquired and evaluated if needed. Effort tolerance is difficult to assess both due to restricted physical activity and poor cognition.
Clinical examination should include survey for any scoliosis and any signs of acute respiratory infections.  Flexion deformities seen in limb extremities may make intravenous access difficult.  Airway examination should focus on TMJ dislocation/contractures and poor dental hygiene with loose tooth etc.
Cerebral palsy per se does not warrant any specific investigations in the perioperative period. The investigation should be based on the type of surgery and associated co morbid illness. Chest X ray may be needed in case of suspected chronic respiratory disease due to recurrent aspiration and any presence of scoliosis.. Even in patients undergoing scoliosis correction pulmonary function test is impossible as this test needs complete cooperation of the patient.
Presence of any acute lower respiratory tract infection needs treatment and control before proceeding for elective procedure. Combination of antibiotic, bronchodilators and physiotherapy is needed in these patients before posting for any elective surgical procedures Malnutrition may need gastrostomy for feeding and optimisation before undertaking any major surgery.
Premedication: Patients on antiepileptic drug need to continue their medications in their perioperative period to avoid any seizure episode. Baclofen therapy for spasticty should be continued as with holding can result in withdrawal symptoms. Pre medication with glycopyrolate is better in patients with pooling of saliva. Patients on sodium valproate may have platelet dysfunction but generally need no dose reduction or discontinuation in the perioperative period.
Intraoperative management:
Induction:
Positioning may be challenging in patients with severe cognitive dysfunction and physical deformities due to contracture. Care to be taken not to dislodge intrathecal infusion pumps if present. If IV access is present propofol is preferred as these patients can have reactive airway due to recurrent infection. Ketamine can increase secretions and postoperative hallucination can be troublesome in this patients. Ketamine is not advisable in patients with epilepsy.
Rapid sequence induction and intubation (RSI) may be considered in patients with GERD. But any predictors of difficult airway such as TMJ dislocation or contracture need to be taken into consideration. Succinylcholine has not been found to increase serum potassium level and can be safely used if RSI is contemplated. (5) Even quadriplegic CP child doesn’t show significant increase in block sensitivity to scoline and does not warrant dose modification. (6) Patients with mental retardation might not allow preoxygenation. Hence RSI needs appropriate modification. Working suction apparatus is needed in any patient undergoing anaesthesia and surgery, more so in patients who are going to have excessive oropharyngeal secretions. Laryngeal mask airway has been successfully used in patients undergoing CT scan without any major events. (7)
Maintenance of Anaesthesia:
Cerebral palsy patients are sensitive to inhalational agents compared to normal children. MAC values are lower for CP child with severe mental retardation. BIS monitoring shows lower MAC values with both halothane and sevoflurane. Concurrent antiepileptic drugs probably influence MAC value further. (8, 9) Resistance to neuromuscular blocking effect of vecuronium is evident in patients with cerebral palsy. This is probably due to up regulation of AcH receptors in the muscles or changes in cholinesterase activity. (10) Performance of regional analgesia technique is challenging before induction due to apprehensive/uncooperative child and presence of movement disorder.  Positioning during anaesthesia should take into consideration of previously existing bed sore or nerve damage. Care should be taken to avoid worsening of these problems and prevent occurrence of any such event. 
Thalamus dysfunction along with poor muscle and fat cover makes CP child prone to hypothermia. Heat conservation strategies including forced warm air, warm IV fluid and irrigation fluid should be used whenever feasible. Despite all these preventive measures maintaining normothermia may still be a problem in these patients.  Recovery from anaesthesia may be delayed due to combination of increased sensitivity to volatile agents and hypothermia.
Postoperative management:
Recovery in unfamiliar environment may cause agitation. This can be avoided if the parents or care takers are present in close vicinity of patient in recovery area whenever possible. Poor communication makes difficulty in pain score assessment and in judging the efficacy of the pain intervention provided. The irritable and restless child may be experiencing pain. Apart from surgical wound inflicted pain, patient may have baseline pain secondary to spasm.
Antispastic medication need to be started earliest possible to prevent any muscle spasm. All routine medication needs to be started as per schedule in the earliest available opportunity.  In case of delay in resuming oral intake alternate route of administration should be used. In hypothermic child continue forced air warmer to rewarm patient.
Compartment syndrome is a possibility and should be monitored carefully. Epidural analgesia may mask early signs of lower limb compartment syndrome and more vigilance is needed.
Presence of URI is identified as risk factor for postoperative respiratory complications. The respiratory complications generally are mild and resolves completely. (7)
Postoperative analgesia:
Postoperative pain following selective dorsal rhizotomy (SDR) has been managed effectively morphine using intravenous, epidural and intra thecal route.
Epidural analgesia with catheter placed under vision by surgeon has been studied in patients undergoing selective dorsal rhizotomy (SDR). Epidural group received 0.2% ropivacaine with hydromorphone (2.5µg/ml)at 0.2ml/kg/hr continuous infusion and systemic opioid group received fentanyl infusion(0.50-1 µg/kg/hr).  Ketorolac has been used in these patients as part of multimodal analgesia. Postoperative pain scores are better and incidence of respiratory depression is less in epidural group. (11) Intrathecal morphine at 10 µg /kg provides similar quality of analgesia compared to 30 µg /kg at 10hrs following SDR. (12) Epidural local anaesthetic based regimen gives better analgesia compared to epidural morphine in children undergoing various abdominal and lower limb orthopaedic surgeries. (13) Hence it is prudent to use regional analgesia whenever possible. Systemic opioids can be an alternative in other cases with severe postoperative pain. Multi modal analgesia improves the pain scores in these patients. Physical therapy should be continued in postoperative period to reduce spastic pain.
Conclusion:
Cerebral palsy is due to insult to developing brain in various stages of development. Clinical presentation is varied and diverse. Cerebral palsy patients can be successfully managed in the perioperative period with adequate preoperative preparation and careful planning with meticulous execution in intraoperative and postoperative period. Team work including parent/care takers, paediatrician, physiotherapist, surgeon, physical therapist along with anaesthesiologist makes surgery and rehabilitation smooth in this special group of patients.
References:

  1. Palisano R, Rosenbaum P, Walter S, Russell D, Wood E, Galuppi B. Development and reliability of a system to classify gross motor function in children with cerebral palsy. Dev Med Child Neurol. 1997;39(4):214-23.
  2. Sankar C and Mundkur N.Cerebral palsy- definition, classification, etiology and early diagnosis. Indian J paediatr 2005;72(10):865-868

Bax M, Goldstein M, Rosenbaum P, Leviton A, Paneth N, Dan B, Jacobsson B, Damiano D; (Executive Committee for the Definition of Cerebral Palsy). Proposed definition and classification of cerebral palsy, April 2005. Dev Med Child Neurol. 2005;47(8):571-6.

  1. Rosenbaum P, Paneth N, Leviton A, Goldstein M, Bax M, Damiano D, Dan B, Jacobsson. A report: the definition and classification of cerebral palsy. April 2006. B.Dev Med Child Neurol Suppl. 2007;109:8-14.
  2.  Theroux MC, Brandom BW, Zagnoev M, Kettrick RG, Miller F, Ponce C. Dose response of succinylcholine at the adductor pollicis of children with cerebral palsy during propofol and nitrous oxide anesthesia. Anesth Analg. 1994; 79(4):761-5.

Dierdorf SF, McNiece WL, Rao CC, Wolfe TM, Krishna G, Means LJ, Haselby KA. Effect of succinylcholine on plasma potassium in children with cerebral palsy. Anesthesiology. 1985;62(1):88-90.

  1. Mello SS, Marques RS, Saraiva RA. Respiratory complications in patients with cerebral palsy undergoing general anesthesia. Rev Bras Anestesiol. 2007;57(5):455-64. 
  2. Choudhry DK, Brenn BR. Bispectral index monitoring: a comparison between normal children and children with quadriplegic cerebral palsy. Anesth Analg. 2002;95(6):1582-5

Frei FJ, Haemmerle MH, Brunner R, Kern C. Minimum alveolar concentration for halothane in children with cerebral palsy and severe mental retardation. Anaesthesia. 1997;52(11):1056-60.

  1. Moorthy SS, Krishna G, Dierdorf SF. Resistance to vecuronium in patients with cerebral palsy. Anesth Analg. 1991;73(3):275-7.
  2. Moore RP, Wester T, Sunder R, Schrock C, Park TS. Peri-operative pain management in children with cerebral palsy: comparative efficacy of epidural vs systemic analgesia protocols. Paediatr Anaesth. 2013;23(8):720-5.

Dews TE, Schubert A, Fried A, Ebrahim Z, Oswalt K, Paranandi L. Intrathecal morphine for analgesia in children undergoing selective dorsal rhizotomy.J Pain Symptom Manage. 1996;11(3):188-94.

 Brenn BR, Brislin RP, Rose JB. Epidural analgesia in children with cerebral palsy. Can J Anaesth. 1998;45(12):1156-61.