Intrathecal Baclofen use in Children and Adolescents

• The Intrathecal Baclofen (ITB) service
• An Introduction - Intrathecal Baclofen (ITB) pumps
  • Figure 1 – Medical and surgical management flowchart for treatment of spasticity
  • Figure 2 – Referral pathway for ITB
• Intrathecal Baclofen test dose
• Intrathecal Baclofen pump insertion
• Intrathecal Baclofen pump dosing and maintenance
  • Figure 3- Choosing a starting dose for a new ITB pump
  • Figure 4 – An example of a standard review timetable for a child with a new ITB pump
• Intensity of reviews
• Elective admission for intense dose escalation or decrease
• ITB pump elective removal
• ITB pump urgent removal
• Elective replacement of ITB pump
• TB pumps after the death of a child or young person
• ITB pumps and MRI scans
  • Figure 5 – Outline of dosing considerations for ITB
• Emergencies
  1. Baclofen Over-dosage
  2. Baclofen Under-dosage
• Appendix 1 – Care plan for patients admitted for intathecal baclofen test dose
  • Pre-operative checklist for test doses
  • Post test dose nursing instructions
• Appendix 2 - Care Plan for patients admitted for ITB Pump Implantation
  • Pre-operative preparation
  • Post operative care following implantation of ITB pump.
  • Discharge advice
• Appendix 3 - ITB Physio Pathway

The Intrathecal Baclofen (ITB) service

The Vision for our service is:

To improve the lives of children with chronic spasticity and/or dystonia and their families through the use of specialist spasticity management approaches with a focus on the use of intrathecal baclofen.

The goals for our service are:

• All children referred to our service will be assessed by a multidisciplinary team and consideration for intrathecal baclofen therapy will be made in a child and family-centred manner.
• Where intrathecal baclofen is not felt to be appropriate, alternative management approaches to improve the child’s symptoms will be suggested wherever possible.
• Where intrathecal baclofen therapy is felt to be appropriate, we will aim to control symptoms no more than 6 months from referral. If this is not achieved the team will review the child’s case and suggestions will be made to change the management plan or suggest alternative treatment options.
• All children with an ITB pump will be managed safely with their and their family’s quality of life at the centre of everything we do.
• Dosing of ITB will be directed by child and family selected goals.

Key people within the service:

Dr Raj Lodh (ITB service lead consultant, Consultant in Paediatric neurorehabilitation)
Mr John Goodden (ITB service neurosurgeon, Consultant Paediatric Neurosurgeon)
Dr Katherine Hulme (Specialty Doctor in Paediatric Neurorehabilitation)
Catherine Wilsmore (Paediatric specialist physiotherapist)
Sharron Peacock (Spasticity nurse specialist)
Andie Mulkeen (Spasticity nurse specialist)

Emergency contact numbers
Paediatric Neurology Ward (L52) - (24/7) 0113 3927452 /0113 3927552 ask for nurse in charge
Clinical Nurse Specialists (Sharron and Andie) - (8am-5pm weekdays) 0113 3922640
Neurosurgical registrar on-call - 07979928120
Dr Raj Lodh / Mr John Goodden / on call paediatric neurologist - mobile phones through switchboard

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An introduction - Intrathecal Baclofen (ITB) pumps

Why?

Intrathecal baclofen is a useful treatment option in carefully selected patients who have chronic spasticity or dystonia resistant to other treatment modalities. Spasticity is the involuntary, velocity-dependent, resistance to movement of a muscle. Dystonia refers to involuntary muscle contractions leading to abnormal movements and postures. Both spasticity and dystonia are common complications of damage or abnormality of the brain.

Baclofen is a muscle relaxant which can be given orally or into the spine (intrathecally). When given intrathecally, baclofen doses required for a similar effect to oral doses are 100 – 1000 x lower. Current ITB pumps offer a significant amount of flexibility in dosing regimes allowing us to tailor treatment regimens to the child’s specific needs.

Who?

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Figure 1 – Medical and surgical management flowchart for treatment of spasticity

(If movement is restricted due to contractures – consider postural management review and orthopaedic referral)

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Figure 2 – Referral pathway for ITB

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Intrathecal Baclofen test dose

Why?

It is a recommendation by the National Institute for Health and Care Excellence (NICE, July 2012) to conduct an intrathecal baclofen test dose on patients who are selected as candidates for ITB pump insertion. The purpose of the test dose is primarily to ensure that the patient does not have an adverse reaction to intrathecally administered baclofen.

A test dose can give an indication of likely response to ITB treatment, however it should be remembered that this is only a one-off dose of intrathecal baclofen. A lack of a beneficial effect from the test dose does not necessarily mean that there will not be benefit from a cumulative dose from an ITB pump. The test dose will also help guide decisions regarding the starting dose of intrathecal baclofen if an ITB pump is to be inserted. Where there is a beneficial effect, the effect can guide further dosing of the ITB pump (i.e. what the desired effect from the ITB pump may ‘look like’).

(Note that an ITB test dose is occasionally used in patients who are being evaluated as possible candidates for Selective Dorsal Rhizotomy. In this scenario, the purpose of the test dose is to establish whether there is any degree of underlying weakness when spasticity is temporarily diminished.)

Who?

All patients will be considered for an ITB test dose before consideration of an ITB pump implantation. However, there are exceptions where an ITB test dose may not be required (to be decided by the MDT only), including:

• Patient had a previous ITB pump which was removed (e.g. due to wound infection or malfunction)
• Symptom control is urgent and a test dose would delay this
• Where it is felt that there is no suitable treatment alternative to ITB (e.g. palliative care)
• Where it is felt that the clinical risk from delaying progression to an ITB pump outweighs benefit of a test dose to decision making (*)

* Since the start of 2020, national ITB services have experienced significant delays in ITB test doses and pump insertions due to the Covid-19 pandemic and disruption to theatre lists. The UK and Ireland paediatric ITB network agreed in September 2021 that progressing directly to an ITB pump (and bypassing an ITB test dose) should be considered as a means of risk of prolonged waits for symptom control. In these situations, a careful MDT assessment and evaluation of response to oral baclofen in the past is felt to be an acceptable alternative to ITB test dose.

How?

The nurse specialist will coordinate arrangements for the patient to attend as a day case. Intrathecal baclofen test doses are administered in theatre by the Neurosurgical team via a lumbar puncture technique under general anaesthetic. In exceptional circumstances (usually where there is a need to see response over a few days), an intrathecal catheter may be used. Please consult appendix 1: Care plan for patients admitted for intrathecal baclofen test dose.

Dosing:
Standard intrathecal baclofen test doses are 50 micrograms as a bolus.
In certain situations, a smaller dose of intrathecal baclofen may be used, i.e. 25 micrograms (for consideration by ITB service Consultant):

• children who have a history of hypersensitivity to oral baclofen
• young children (<4 yrs) or children with a low body weight (<15kg)
• where there is significant concern about possible side effects for any other reason

ITB test dose assessment:
Assessment of response to ITB test doses will be conducted by ITB service consultant, a spasticity team physiotherapist and a specialist nurse. A pre-test dose and post-test dose assessment should be conducted. The post-test dose assessment should be at least 3 hours post administration of intrathecal baclofen.

Assessments should include:

1. Pre-test dose

• general clerking and medical examination (paediatric neurology SHO)
• review by ITB service consultant and spasticity nurse specialist
• physiotherapy examination of tone, joint range of movement, posture and degree of dystonia (see appendix 3)
• videoing of any specific goals highlighted by assessment (e.g. ease of dressing)

2. Post-test dose

• review by ITB service consultant and spasticity nurse specialist, recording of any adverse effects
• physiotherapy examination as above (see appendix 3)
• videoing of any specific goals highlighted by assessment (e.g. ease of dressing)

Signs of Baclofen Overdosage – notify paediatric neurology consultant on-call and ITB service consultant immediately

• Excessive weakness of muscles beginning in the lower limbs first.
• Loss of head control
• Difficulty swallowing/increased salivation
• Nausea and vomiting.
• Increased sedation and excessive sleepiness.
• Urinary retention
• Dizziness.
• Fits (seizures)
• Severe overdose can affect the child’s breathing and they may require intensive care and ventilation.

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Intrathecal Baclofen pump insertion

Why?
Indications for intrathecal baclofen management of spasticity and dystonia are detailed above.

Who?
All children deemed appropriate following an assessment by the joint spasticity multidisciplinary team (or for acute inpatients – the neurorehabilitation team). All children will have a satisfactory test dose outcome (see figure 2 above) or have appropriate reasons for proceeding without a test dose (see ‘ITB test dose’ section above).

How?
The spasticity nurse specialist will liaise with ITB service neurosurgical team, the pump manufacturers (technical support) and the family in order to determine an appropriate elective admission date for ITB pump insertion. A care plan for patients attending for ITB pump insertion is detailed in appendix 2.

It is important to note the following points with regards to patients who have undergone ITB pump insertion

• The ITB pump will be programmed in theatre to commence delivering baclofen immediately (starting dose as per figure 4).
• All patients who have had an ITB pump inserted should have a post-operative PA / Lateral chest + abdomen x-ray to check catheter tip site.
• For children with significant dystonia, the paediatric neurosurgical team may sometimes leave a lumbar catheter in situ at the time of ITB pump insertion. This will usually remain in place for 3 days (depending on neurosurgical opinion).

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Intrathecal Baclofen pump dosing and maintenance

The starting dose for the ITB pump will be determined by ITB service consultant in combination with the spasticity nurse specialists. The general guideline to selection of starting dose is represented below (figure 3).

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Figure 3- Choosing a starting dose for a new ITB pump

(Note – This diagram assumes that goals have not been met at each stage, please also consult figure 5 regarding dose increases). All doses are in MICROGRAMS (mcg).

Regular reviews (see figure 4) will be made and doses adjusted accordingly. Dosing decisions will be made in a multidisciplinary manner and be led by the selected goals of the child and family. GPs and local paediatricians will be informed of changes and refill dates by means of ITB patient review letters.

There are 3 dosing modes for the Medtronic ITB pump (continuous, flexdose, pulsed dose). The selection of the most appropriate dose and dosing mode will be decided by the spasticity team and will generally be decided according to the factors outlined in figure 5.

(There is another dosing mode which involves patient / family delivered boluses (MyPTM), however this is not practically useful for ITB pumps treating spasticity / dystonia for various reasons. It is more commonly used in adult palliative care where the ITB pump can be used to deliver opiate analgesia)

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Figure 4 – An example of a standard review timetable for a child with a new ITB pump

(flexible according to response and family circumstances)

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Intensity of reviews

The nature of spasticity and dystonia means that the impact of symptoms on a child will vary with time. At times when dosing changes are made to address ‘unstable’ symptoms, a period of more intense review by members of the MDT may be required. The frequency of the reviews will be dependent on the nature of the symptoms and holistic considerations, such as impact of frequent review appointments, etc. Where possible, telephone reviews are used in order to reduce hospital attendance.

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Elective admission for intense dose escalation or decrease

In order to allow more rapid escalation or decrease of doses in a safe environment, the MDT team may also decide to electively admit a child to L52; such a decision clearly needs to balance the benefits regarding symptom control against the disadvantages to the family (e.g. time off school, distance from home, etc). Children who have not responded to rapid dose escalation or to a total dose of 300micrograms/day will be considered for elective admission.

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ITB pump elective removal

There are situations where it is deemed necessary or beneficial to withdraw ITB therapy. For children who do not require a rapid pump removal, a timetable of gradual dose reduction should be devised. A referral for pump removal will be made to the ITB Neurosurgical team on successful withdrawal of ITB therapy. There are occasions where removal of the pump is not deemed appropriate, for example, palliative care patient or family / child choice. For specific consideration of children and young people who have an ITB pump but have sadly died, see below (page 12)

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ITB pump urgent removal

Should there be a need for more rapid pump removal, the child should be admitted to the Children’s Neurosciences ward and an appropriate plan should be agreed by the MDT team (including Neurosurgery).

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Elective replacement of ITB pump

The most common reason for replacement of an ITB pump is due to end of battery life, the neurosurgical team will be notified at least 12 months prior to the estimated end of battery life date. Prior to replacement, families will be consulted regarding their desire to continue with ITB therapy and/or to consider alternative treatment options.

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ITB pumps after the death of a child or young person

If a child or young person with an ITB pump dies, the ITB team would be happy to support the treating hospital or hospice with discussions regarding the ITB pump. Depending on the family’s wishes there are several options:

In the case of a family preferring a cremation:

• The ITB pump must be removed. The funeral directors must be informed of the presence of the ITB pump.
• Usually a technician at the funeral directors would be prepared to remove the ITB pump prior to cremation.
• The ITB team are happy to assist with these discussions if they are contacted with relevant details

In the case of a family preferring a burial, the following options are available:

• The ITB pump can be left on. In this situation, the pump will emit a quiet alarm from the time at which it is almost empty of medication until the battery of the pump is discharged (this may be up to 6-7 years for a new pump). The alarm is quiet and will not be audible to others.
• The ITB pump can be stopped by the ITB team. We will need to visit the child or young person and use a device to read the pump and programme it to stop. The pumps can only be stopped using a unique code provided by Medtronic (manufacturers of the pumps) – the code is specific to the particular day that the pump is being stopped. The pump will not emit an alarm at any point in the future. Please contact the team to let us know that this is the family’s wish as soon as possible, so that we can make appropriate plans for someone to facilitate this from our team. Please note that where there is need for a burial at short notice, although we will do our utmost to provide someone to turn the pump off, in rare situations this may not be achievable.
• The ITB pump can be removed. This is usually done by a technician at the funeral directors. We are happy to assist with these discussions if we are provided with relevant details.

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ITB pumps and MRI scans

The following is an excerpt from the Medtronic website regarding MRI scanners:
“The magnetic field of the MRI scanner will temporarily stop the rotor of the SynchroMed II pump motor and suspend drug infusion for the duration of the MRI exposure. The pump should resume normal operation upon termination of MRI exposure; however, there is the potential for an extended delay in pump recovery after exiting the MRI magnetic field because exposure to the MRI magnetic field may cause the motor gears within the pump to bind temporarily without permanent damage. This is caused by the potential for backward rotation of the pump rotor magnet when it aligns with the MRI magnetic field. This temporary binding may delay the return of proper infusion after the pump is removed from the MRI magnetic field. While extended delays in pump recovery are unlikely, reports have indicated that there is the potential for a two to twenty-four hour delay in return to proper drug infusion after completion of an MRI scan.”
Any child with an ITB pump who requires an MRI scan should be notified to the spasticity specialist nurse. The presence of an ITB pump should be clearly marked on the MRI request. When a child attends for an MRI scan, the presence of an ITB pump should be notified to the MRI department. The presence of an ITB pump does not preclude an MRI scan for the child, but close monitoring of pump function needs to be undertaken before and after the MRI scan.

In the unlikely event of a pump not restarting within 4 hours after an MRI scan, the child should receive an oral dose of baclofen (see below for dosing) and the specialist spasticity nurse will liaise with ITB service consultant and Medtronic.

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Figure 5 – Outline of dosing considerations for ITB

1. Pulsed dosing refers to a dosing mode where there is a combination of very low rate continuous infusion of baclofen with additional (usually 6) boluses of baclofen. There is evidence to suggest that in patients with significant dystonia, the use of pulsed dosing results in better response to baclofen at lower total doses and less side effects.
2. Flexdose refers to a dosing mode where there are variable rates of baclofen delivered at different time periods (e.g. night vs day, times of being dressed vs rest, etc). This is dependent on identifying particular periods in the day where tone is consistently more or less problematic.

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Emergencies

All children admitted for management of emergencies should be urgently brought to the attention of the ITB specialist nurse and consultant (and if out of hours, the on-call paediatric neurology consultant).

Any children presenting acutely will require interrogation of their ITB pump to help establish cause. This is done by appropriately trained members of the ITB team and, if unavailable, through the Medtronic technical support team. However, treatment of symptoms should not be delayed pending interrogation of ITB pump.

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1. Baclofen Over-dosage

Mild Overdose

Moderate Overdose

Severe Overdose

Never stop the ITB pump - always set at minimum rate which will deliver a minute non-therapeutic dose.

A high percentage of ITB severe overdose and withdrawal is due to human error, including:

• Pump programming & catheter priming (initial implant, catheter revision, pump replacement)
• Incorrect programming following a dose adjustment and or drug concentration
• Miscalculation of pump refill date
• Incorrect planning of pump replacement date
• Incorrect programming of pump alarms (low drug levels and battery life)
• Incorrect management of patient with ITB pump
• Failure to check pump has restarted after MRI

Withdrawal or overdosage may be due to catheter related problems (e.g. fracture or migration of catheter) and pump malfunction.

Symptoms can be severe and abrupt or mild and gradual.

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2. Baclofen Under-dosage

Mild to moderate underdosage

Moderate underdosage

Severe underdosage (acute withdrawal)
NOTE requires URGENT management as there is a significant risk of death and serious morbidity.

DOSAGES
Oral Baclofen:

• < 30kg weight 10mg 6-8 hourly
• 30-50kg weight 15mg 6-8 hourly
• >50kg weight 20mg 6-8 hourly)

Oral Clonidine:

• Commence 1microgram/kg 6-8 hourly,
• Dependent on clinical response, daily increases as required to maximum of 25 micrograms/kg/24 hours)

IV Midazolam infusion: 150microgram/kg loading followed by continuous infusion 2 micrograms/kg/min increased according to response every 30 mins to a maximum of 4 micrograms/kg /min.

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APPENDIX 1 – Care plan for patients admitted for intathecal baclofen test dose

Pre-operative checklist for test doses

• Patient in a highly observable area on the ward
• Parent/ carer resident/ available to assist with the evaluation of the results of the test dose
• General medical clerking completed (paediatric neurology team)
• Consent completed by neurosurgical team
• Pre-ITB physiotherapy assessment & video recording completed
• Baseline nursing observations (temp, BP, pulse, respirations & oxygen saturation and GCS) conducted and results satisfactory
• Patient has been written up for (and administered) all usual medications (including oral baclofen)
• Intrathecal baclofen dose prescribed as a stat dose on front of the patients drug chart and ordered from pharmacy
• Intrathecal baclofen ready for sending to theatre with the patient (Note: ITB must be stored in a separate/lockable fridge which has been identified on Ward L52 and sent to theatre with the patient and drug chart).

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Post test dose nursing instructions

• Child is monitored for adverse effects and observations recorded ½ hourly for the first 4 hours then hourly for the next 2 hours, then 2 hourly for the next two hours, and return to 4 hourly observations (BP, pulse, respirations, oxygen saturation & GCS) before discharge.
• Monitor LP site for signs of leakage, child must be on flat bed rest for 2 hours, then sitting up only for a while, before being allowed to walk or sit in chair to try and reduced the risk of headache symptoms post lumbar puncture.
• Continuous oxygen saturation monitoring throughout observation period.
• Physiotherapy assessment 3-4 hours following the test dose.
• Continue with child’s usual drug regime including oral Baclofen throughout the whole test dose procedure.

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APPENDIX 2 - Care Plan for patients admitted for ITB Pump Implantation

Pre-operative preparation

• All patients having implantation of ITB pumps should be nursed on ward L52.
• General clerking procedure, pre-operative bloods (U/E’s, FBC & Clotting) only if indicated.
• Consent obtained by the paediatric neurosurgical team
• Ensure ITB infusion is prescribed by the ITB service consultant and ordered from pharmacy.
• ITB must be stored in a separate/lockable ITB fridge which has been identified on ward 52.
• Patient to continue with usual drug regime including oral baclofen.
• Discuss post-operative analgesia requirements with the paediatric anaesthetist.
• Ensure ITB prescription and drug chart goes to theatre with the patient

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Post operative care following implantation of ITB pump.

• The ITB pump will be filled and a treatment dose set to commence immediately.
• Half hourly post operative observations (BP, pulse, respiration, SaO2, temp, GCS) & lumbar and abdominal wound site checks for 4 hours, then hourly observations for 4 hours, then two hourly for four hours, continue with four hourly observations until discharge
• IV antibiotics for 24hours post operatively.
• Regular pain assessment and analgesia.
• Commence feeding when able to tolerate.
• Bed rest for 48hours then if no leaking or swelling to sit up when comfortable.
• After the operation the wound is covered with a dressing and sticky paper plasters. The dressing can be removed after a couple of days but the sticky paper plasters must be kept on and dry for 10 days. After 10 days the child may shower and the paper plasters will gradually fall off.
• Post operative PA / Lateral chest + abdomen x-ray to check catheter tip site (before discharge).
• Unless otherwise specified by the ITB service consultant, patients to carry on with usual oral baclofen dose until there is deemed to be a response to ITB (this is usually after discharge).
• Patient will be reviewed daily by a member of the ITB team and dose adjustments made according to the child’s response to treatment.
• Discharge prescription (TTO) - analgesia and, if deemed appropriate by the ITB service consultant, reducing doses of oral baclofen.

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Discharge advice

All discharge advice and appointments with be organised by the spasticity nurse specialist

• Wound care and activity advice.
• Discharge advice regarding Baclofen Withdrawal & Overdose (signs and symptoms) and emergency contact numbers must be given to patient before discharge.
• Patients GP to receive Baclofen Withdrawal & Overdose information (signs and symptoms) and emergency contact numbers. GP to be requested to add IT baclofen to issued elsewhere section of their prescribing system.
• Appointment with spasticity nurse specialist for ITB review & dose assessment one week post operatively.
• Written instructions/ discharge prescription regarding reducing/stopping oral baclofen as prescribed by the ITB service consultant, if applicable.
• Liaise with school nurse/GP/local paediatrician & district nurse etc.
• Regular appointments with spasticity nurse specialist, ITB service consultant and Physiotherapist for ITB therapy assessments and dose adjustments. .
• 3-6 monthly ITB pump refills by spasticity nurse specialist.

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APPENDIX 3 - ITB Physio Pathway