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Algos
Transforaminal Lateral Recess Block
Techniques
The lateral recess may be approached by direct needle or catheter placement,
or by diffusion as with a caudal block. The direct needle placement is the most
accurate method of targeting tissues inside the spinal canal, however special
skills and understanding of the anatomy are necessary for performance of the
block. Blunt needles only should be employed anywhere medial to the
mid-pedicular line.
In the case shown at the left, a 78 year old lady developed symptoms of
neurogenic claudication which was steadiy worsening. She was diagnosed with
a recent onset of psoriasis over the lumbosacral spine, including the
sacrococcygeal hiatus. The segmental stenosis was diffuse, but worse at the
L3-4>L4-5 segment. It was elected to avoid not only placement of a needle
through the skin lesions (very painful to touch or to betadine) over the posterior
spine but also over the sacral-coccygeal hiatus.
Because the patient was not obese, the spinal neuroforamen lie quite posterior,
and a more acute angle to the skin is employed. The down the beam method
may be used with the caveat that the needles used may impinge on the
fluoroscopic image intensifier due to their length. The target angle is
approximately 25 degrees inferior to superior, and 40-50 degrees oblique from
the coronal plane (50-40 degrees from the sagittal plane). A more acute angle
may risk penetrating the abdominal cavity, especially in the obese. A 16 ga
Angiocath introducer needle is inserted through the skin in the above
trajectories, and the needle is removed leaving the sheath. A 20ga blunt needle
is subsequently advanced through the sheath, the multifidus muscle fascia
(pop!), the transforaminal ligaments, and subsequently into the lateral recess
with the tip being placed approximately 1 mm medial to the medial pedicular
line. Following a negative aspirate for blood or CSF, the needle is injected
under live fluoroscopy or digital subtraction with a non-ionic contrast (eg.
Omnipaque, Isovue). Providing the desired structures are visualized depending
on the reason for the block, a steroid (celestone, depomedrol, etc) is injected
without moving the needle from the time of the neurogram. No local anesthetic
is typically injected into the neuroforamien due to the propensity for its
presence to make potential acute neurological injury difficult to diagnose. Local
anesthetics act only to obfuscate the cause of neurological injury , may cause
excessive leg weakness in the immediate post-injection period, and may cause
a delay in the diagnosis of spinal cord infarction or epidural hematoma. In this
case, the epidurogram demonstrated layering in the lateral epidural space.
TFLRB may also be used in cases of significant foraminal stenosis, paracentral
or lateral disc herniation, etc. to target the disc herniation itself, the anterior
epidural space, etc. In the above case with spinal stenosis, bilateral injections
were undertaken.
or by diffusion as with a caudal block. The direct needle placement is the most
accurate method of targeting tissues inside the spinal canal, however special
skills and understanding of the anatomy are necessary for performance of the
block. Blunt needles only should be employed anywhere medial to the
mid-pedicular line.
In the case shown at the left, a 78 year old lady developed symptoms of
neurogenic claudication which was steadiy worsening. She was diagnosed with
a recent onset of psoriasis over the lumbosacral spine, including the
sacrococcygeal hiatus. The segmental stenosis was diffuse, but worse at the
L3-4>L4-5 segment. It was elected to avoid not only placement of a needle
through the skin lesions (very painful to touch or to betadine) over the posterior
spine but also over the sacral-coccygeal hiatus.
Because the patient was not obese, the spinal neuroforamen lie quite posterior,
and a more acute angle to the skin is employed. The down the beam method
may be used with the caveat that the needles used may impinge on the
fluoroscopic image intensifier due to their length. The target angle is
approximately 25 degrees inferior to superior, and 40-50 degrees oblique from
the coronal plane (50-40 degrees from the sagittal plane). A more acute angle
may risk penetrating the abdominal cavity, especially in the obese. A 16 ga
Angiocath introducer needle is inserted through the skin in the above
trajectories, and the needle is removed leaving the sheath. A 20ga blunt needle
is subsequently advanced through the sheath, the multifidus muscle fascia
(pop!), the transforaminal ligaments, and subsequently into the lateral recess
with the tip being placed approximately 1 mm medial to the medial pedicular
line. Following a negative aspirate for blood or CSF, the needle is injected
under live fluoroscopy or digital subtraction with a non-ionic contrast (eg.
Omnipaque, Isovue). Providing the desired structures are visualized depending
on the reason for the block, a steroid (celestone, depomedrol, etc) is injected
without moving the needle from the time of the neurogram. No local anesthetic
is typically injected into the neuroforamien due to the propensity for its
presence to make potential acute neurological injury difficult to diagnose. Local
anesthetics act only to obfuscate the cause of neurological injury , may cause
excessive leg weakness in the immediate post-injection period, and may cause
a delay in the diagnosis of spinal cord infarction or epidural hematoma. In this
case, the epidurogram demonstrated layering in the lateral epidural space.
TFLRB may also be used in cases of significant foraminal stenosis, paracentral
or lateral disc herniation, etc. to target the disc herniation itself, the anterior
epidural space, etc. In the above case with spinal stenosis, bilateral injections
were undertaken.