Diagnostic ultrasound ( PDFDrive )

900 PART III Small Parts, Carotid Artery, and Peripheral Vessel Sonography
PRE-INJECTION
POST-INJECTION
N
fh
A
fn
B
FIG. 25.3 Long-Axis Approach: Injection of Left Hip. The long-axis approach is suitable for deep joint injections, such as the hip or shoulder.
(A) Before injection, 22-gauge spinal needle (N) has been positioned at the femoral head-neck junction in a 50-year-old woman with a labral tear
demonstrated on magnetic resonance imaging (not shown), to assess relief after therapeutic injection. (B) After injection, conirmation of intraarticular
deposition of injected material is obtained by the presence of microbubbles (arrows) deep to the joint capsule. fh, Femoral head; fn, femoral neck.
See also Video 25.1.
PRE-INJECTION
POST-INJECTION
C
N
N
M
P
A
B
FIG. 25.4 Short-Axis Approach for Injection of First Metatarsophalangeal (MTP) Joint. (A) Long-axis view shows 25-gauge needle positioned
in MTP joint of 53-year-old woman with plantar plate injury; needle (N) is seen in cross section. M, Metatarsal head; P, proximal phalanx. (B) While
monitoring the injection in real time, the joint capsule distends and ills with echogenic material. C, Capsule.
and surrounded by a sterile drape. A drape is also placed over
portions of the ultrasound unit. A sonographer or radiologist
positions the transducer; a radiologist positions the needle and
performs the procedure. We use 1% lidocaine and bupivacaine
(0.25%-0.75%) for local anesthesia. Once the needle is in position,
the procedure is undertaken while imaging in real time. Depending
on anatomic location, a 1.5-inch or spinal needle with stylet is
used to administer the anesthetic-corticosteroid mixture, generally
consisting of local long-acting anesthetic and one of the standard
injectable corticosteroid derivatives (e.g., triamcinolone).
Two approaches to performing injections are long axis and
short axis, which relate needle orientation to the structure being
injected. 9 he long-axis approach refers to needle placement in
the plane parallel to the structure of interest (Fig. 25.3). For
example, longitudinal imaging of the hip to display a hip efusion
might be used as the plane to direct the needle for ultrasoundguided
aspiration. Alternatively, the short-axis approach refers
to needle entry in the plane perpendicular to the long axis of a
structure (Fig. 25.4). For example, injection of the retrocalcaneal
bursa or metatarsophalangeal (MTP) joint might use a lateral
approach. In my experience, the short-axis approach works well
when performing injections or aspirations in small joints and
tendon sheaths of the hand and foot. he long-axis approach
appears better suited for deep joint injections, such as in the hip
or shoulder. It is important to recognize, however, that such
approaches serve merely as guidelines and that no single method
necessarily applies to any speciic injection.
INJECTION MATERIALS
Most injections involve use of a long-acting corticosteroid in
combination with a local anesthetic in relatively small volumes.
Injectable steroids usually come in either a crystalline form,
associated with a slower rate of absorption, or a soluble form,
characterized by rapid absorption. 20-22 Crystalline agents include
triamcinolone and methylprednisolone acetate (Depo-Medrol).
A common soluble agent is Celestone, which includes a rapidly
absorbed betamethasone salt. A reactive inlammatory response
or lushing response may occur with crystalline steroids, but
typically not with soluble agents. 13