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INTRATHECAL
BACLOFEN THERAPY
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SPASTICITY
Defined as a velocity-dependent resistance to
passive movement of a joint and its associated
musculature
Characterized by hyper excitability of the stretch
reflex related to the loss of inhibition from
descending supraspinal structure
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Must only be treated when excess tone leads
to functional losses, impairment of
locomotion, or deformities
Surgical procedures must be performed so
that excess of tone be reduced without
suppressing useful muscular tone or impairing
any residual motor/sensory functions.
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Managing spasticity
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Mechanism of action of main pharmacological anti-spastic treatments.
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Baclofen
Binds to GABA-B receptors that are found
throughout the neuroaxis
Most of its action occurs at the presynaptic
terminals, decreasing calcium influx and
consequently reducing neurotransmitter
release
Main adverse effects of oral baclofen :
sedation or somnolence, excessive weakness.
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TECHNICAL NOTE
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HISTORY
1985
Pump implanted
subcutaneously
associated with poor
healing and wound
dehiscence
1998
Grabb & Pittman
Subfascial technique
lowering the risk of skin dehiscence
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Patient Positioning
Left decubitus position with flexed hips and
knees
A soft pillow is placed under the hips and
between the knees to avoid pressure sores
Upper arm is held away from the surgical field
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Surgical preparation
Antibiotics are administered at the time of
anesthesia induction
Operating field is prepared with chlorhexidine
and adhesive sterile draping
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Implant Site Selection
The preferred surgical side is the right (for
right handed)
A transverse skin incision is made in the right
hypocondrium at the level of the upper third
of line running between the xyphoid process
and pubic ramus
Avoid contact with the lower end of the rig
cage
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Dissection
Incision is deepenedthrough the subcutaneousfat
Care is made not to
dissect it from the musclefascia to avoid creatingdead space
A single plane is created
down to the rectussheath, and both thelateral and medial edgesof the rectus abdominisare identified.
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The fascia of the
rectus sheath is incised
horizontally and is
continued laterallyinto the full thickness
of the external oblique
muscle.
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At the medial side of the wound, the anteriorlayer of the fascia of the internal oblique musclemerges with its posterior fascial layer over the
lateral edge of the rectus abdominis muscle at avariable distance along the line of lineasemilunaris
Cutting in between these internal oblique layers
help to open a natural plane between theexternal oblique muscle anteriorly and theinternal oblique, transversus abdominis, andperitoneum posteriorly.
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In summary, a space is created starting
beneath the anterior rectus sheath medially,
continuing laterally under the externaloblique.
The internal oblique, the transversus
abdominis, and the peritoneum constitute theposterior wall of this pouch
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Checks
Pump will fit inside the pouch
Fascia will close easily over the entire pump
and connector
There is sufficient place to connect the
catheter
No bleeding
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Spinal Acces
Level of insertion: L3-4
Skin is incised 2 cm over the lumbar spine
down to the supraspinous fascia in the
interspinous space
A 14-gauge Tuohy needle is used to access the
thecal sac
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Spinal Access
The entry point is made 1-1.5 cm from themidline away from the interspinous ligamentto avoid fracture of the catheher after
insertion Do not enter too laterally beyond the pedicle
to avoid catheter migration as the thin fasciallayer and increased muscle bulk laterally couldpotentially increase the differential motionand lead to migration of the catheter
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Tunneling
Tunneling is performed from subfascial pouch
in the abdomen and is directed to the lumbar
incision
Tunneling device leaves the pump side from
inside the subfascial pouch by passing
between the muscle layer and its fascia to end
up in the subcutaneous tissue
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Tunneling
Before attaching the catheter to the pump
connector, make a check that CSF is draining
and the catheter is secured with the
connector with silk ties
The full length of the catheter is left without
shortening and remaining tube is coiled
behind the pump and over the lumbar fascia
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Postoperative Course
Stay in the hospital for at least 48 hours to
make sure there is no wound leak or
postlumbar puncture syndrome
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Operation Duration
Varies between 50 and 150 minutes, with an
average of 70 minutes
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Pump
Photographic (A) and radiographic (B) representations of the SynchroMed model EL intrathecal
baclofen pump depicting the pump rotor (red ring), reservoir port (yellow arrow ), catheter-
access port (blue arrow), and the pump connector (magenta arrow).
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Outcome
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Complication
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Baclofen Dose
The average dose of intrathecal baclofenstarted at 200 mcg a day and increased overtime for the first year or two and then
stabilized below 400 mcg a day. the amount of baclofen infused usually has to be
increased in the first 612 months. In mostpatients, it stabilizes by a year to 2 years and
further increases in dosage are not necessary. The range of effective dosing is quite large. Some
patients are well controlled with 25 mcg per dayand other patients may need over 1000 mcg a day
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Baclofen Withdrawal Syndrome
MH: Malignant
Hyperthermia
NMS: Neuroleptic Malignant
Syndrome
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