Diagnostic ultrasound ( PDFDrive )

902 PART III Small Parts, Carotid Artery, and Peripheral Vessel Sonography
AC JT
A
FIG. 25.7 Short-Axis Approach to Injection of Acromioclavicular
(AC) Joint. A 25-gauge needle (long thin arrow) is seen in cross section
in a distended hypertrophic AC joint during therapeutic injection in
73-year-old woman with pain centered over AC joint. The joint appears
widened, containing echogenic material caused by the contrast effect
(short thick arrow) of the therapeutic agent. A, Acromion; C, distended
capsule; CL, clavicle.
used in evaluating the joint for an efusion. Ideally, the anterior
capsule is imaged at the head-neck junction of the femur. In this
approach the scan plane is lateral to the neurovascular bundle.
he needle may be directed into the joint while maintaining its
position in the scan plane of the transducer. A test injection of
1% lidocaine conirms the intraarticular needle position, and
the therapeutic injection follows.
Fibrous joints, such as the acromioclavicular (AC) joint, can
likewise be injected using ultrasound guidance (Fig. 25.7). A
short-axis technique is employed similar to that used in the foot.
he majority of these injections can be performed using a 1.5-inch
needle with a small volume (0.5-1.0 mL) of therapeutic mixture.
In addition to the AC joint, this approach is useful in the sternoclavicular
joint and pubic symphysis.
SUPERFICIAL PERITENDINOUS AND
PERIARTICULAR INJECTIONS
Peritendinous injection of anesthetic and long-acting corticosteroid
is an efective means to treat tenosynovitis, bursitis, and
ganglion cysts in the hand, foot, and ankle. hese structures
are supericially located and well delineated on sonography.
Ultrasound-guided injections are an efective means to ensure
correct localization of therapeutic agents.
Foot and Ankle
In my experience, peritendinous injections in the foot and ankle
are most oten requested for patients with chronic achillodynia
or those with medial or lateral ankle pain caused by posterior
tibial or peroneal tendinosis or tenosynovitis. Less oten, patients
are referred to help diferentiate pain from posterior impingement
and stenosing tenosynovitis of the lexor hallucis longus (FHL)
tendon. 26 his distinction can be diicult, sometimes requiring
diagnostic and therapeutic injection of the corresponding tendon
sheath. Patients with plantar foot pain caused by plantar fasciitis
and forefoot pain resulting from painful neuromas are also
frequently referred for ultrasound-guided injections. 27,28
he large majority of patients with achillodynia have pain
referable to the enthesis, with associated retrocalcaneal bursitis
C
CL
and Achilles tendinosis. Enthesis is the site of attachment of a
muscle or ligament to bone where the collagen ibers are mineralized
and integrated into bone. A retrocalcaneal bursal injection
may help alleviate local pain and inlammation (Fig. 25.8). I
scan the patient in a prone position with the ankle in mild
dorsilexion, using a linear transducer of 10 MHz or higher
frequency. A 1.5-inch needle usually suices in these patients,
with placement using a short-axis approach. he deep retrocalcaneal
bursa is usually well seen. A small amount of anesthetic
will help conirm position by active distention of the bursa in
real time.
We similarly approach posterior tibial or peroneal tendons
in short axis (Fig. 25.9). Patients with pain in this distribution
have been shown to beneit from local tendon sheath injections.
he presence of preexisting tendon sheath luid can facilitate
needle visualization. However, careful scanning should be done
before the procedure to assess the needle trajectory relative to
adjacent neurovascular structures. Use of color or power Doppler
imaging can facilitate visualization of the neurovascular bundle.
he posterior tibial nerve is closely related to adjacent vascular
structures and is usually well seen before bifurcating into medial
and lateral plantar branches. Fluid frequently is seen in relation
to the posterior tibial tendon, in the submalleolar region. he
location of the peroneal tendon is less predictable. Use of power
Doppler sonography in conjunction with real-time guidance can
help localize areas of inlammation for guided injection. In stenosing
tenosynovitis the tendons may be surrounded only by a
thickened retinaculum, proliferative synovium, or scar tissue.
In this case, use of a test injection of local anesthesia can be
invaluable to conirm the distribution of the therapeutic agent
within the tendon sheath in real time.
he lexor hallucis longus (FHL) tendon poses a more challenging
problem because of its close relation to the neurovascular
bundle of the posterior medial ankle. One helpful feature in
performing FHL tendon sheath injections is that tendon sheath
efusions tend to localize at the posterior recess of the tibiotalar
joint. he neurovascular bundle is easily circumvented by placing
the needle lateral to the Achilles tendon while scanning medially
(Fig. 25.10). his approach allows lexibility in needle placement
while maintaining the needle perpendicular to the insonating
beam.
Ultrasound diagnosis of plantar fasciitis includes thickening
of the medial band of the plantar fascia and fat pad edema. One
treatment option for severe plantar fasciitis is regional corticosteroid
injection, typically performed using anatomic landmarks.
However, “blind” injections into the heel have been associated
with rupture of the plantar fascia and failure of the longitudinal
arch. 13 Ultrasound can be used to guide a needle along the plantar
margin of the fascia, thus avoiding direct intrafascial injection. 26
he plantar fascia is imaged with the patient prone and the foot
mildly dorsilexed, using a long-axis approach. he transducer
is centered over the medial band, which is most oten implicated
in these patients. A mark is placed over the posterior aspect of
the heel and the needle advanced supericial to the plantar fascia,
approximately to the margin of the medial tubercle (Fig. 25.11).
I perform a perifascial injection using this approach, monitoring
the distribution of injected material in real time.