Ultrasound-guided joint and soft tissue interventions

Abstract

Minor procedures with an injection needle are frequently performed in orthopedic clinics. They may be of a diagnostic, diagnostic and therapeutic or purely therapeutic nature. Ultrasound guidance while inserting the needle allows for a safe medicine administration and evacuation of fluid contents. It improves the efficacy of such procedures by ensuring accurate needle insertion in the target site. Ultrasound-guided procedures reduce the duration of treatment (e.g. medicines reach the target site directly; all fluid collections are removed, even multilocular ones) and minimize pain (by the selection of optimal access sites omitting tendons, vessels and peripheral nerves). This paper presents the principles of performing ultrasound-guided interventions. A detailed description of such a technique is provided and the most commonly injected medicines as well as their adverse reactions and contraindications are discussed. Attention is also paid to image optimization and the role of procedure site selection with the exclusion of other pathologies in the puncture site (such as tumors, foreign bodies and vascular or nerve pathologies). What is more, the author also discusses the principles of needle length and thickness selection as well as the manners of its insertion in relation to the transducer. Moreover, the principles of aseptics that are mandatory during such interventions are also presented and the way to protect transducers from the effects of chemical disinfectants is discussed. Furthermore, the paper contains numerous photographs of performed interventions. It is addressed to clinical practitioners and its aim is to facilitate and improve the efficacy of the procedures which are commonly performed in orthopedics. Ultrasound guidance of joint and soft tissue interventions should become a gold standard in all orthopedic clinics.

Introduction

Minor procedures with an injection needle are frequently performed in orthopedic clinics. They may be of a diagnostic, diagnostic and therapeutic or purely therapeutic nature. Real-time ultrasound guidance enables accurate performance of such procedures. The technique is used for evacuation of fluid contents or administration of medicines (fig. 1).

Fig. 1.

Example injection – administering medicine to a ganglion on the dorsal side of the wrist

An advantage of ultrasound-guided (US-guided) procedures is the control of the needle insertion path and, if needed, the possibility to modify the needle depth or angle without the risk of damaging adjacent structures^(1–5).

Principles and technique of ultrasound-guided procedures

When performing US-guided procedures, one needs to observe specific principles, which ensures effective and safe performance.

First of all, when performing injection without assistance, an appropriate set of tools should be prepared. It should contain needles of various sizes, syringes, sterile gloves, ultrasound probe covers, skin antiseptics, dressing materials as well as medicines to be used and physiological saline⁽²⁾ (fig. 2).

Fig. 2.

Set of tools containing needles of various sizes, syringes, sterile gloves, ultrasound probe covers, skin antiseptics, dressing materials, medicines and physiological saline

Particular attention should be paid to aseptic principles regarding the patient, physician and used equipment. In standard ultrasound apparatuses, transducers are not resistant to the effects of disinfectants. Hence, their protection with ultrasound covers is vital. A transducer prepared is such a way should be disinfected with spirit which in this situation, also serves as ultrasound conductor instead of conventional gel^{(2, 3, 5)} (fig. 3).

Fig. 3.

US transducer protected by a cover

The usage of sterile surgical drapes is optional, e.g. they are used when there are skin lesions (psoriasis or atopic dermatitis) in the direct vicinity of the puncture site. The presence of such lesions in the planned puncture site constitutes a direct contraindication to the procedure. Drapes should also be used when longer intervention is anticipated, e.g. growth factor injections.

Prior to inserting a needle, it is necessary to thoroughly evaluate a given region by means of ultrasound in order to rule out the presence of any pathological changes (tumors, foreign bodies and vascular or nerve pathologies) (fig. 4A, B). In the author's own practice, she observed several situations when a clinician “blindly” punctured a “ganglion” which, following a US examination, occurred to be a benign tumor (lipoma).

Fig. 4.

A. Ganglion originating from the tibiofibular joint. B. Malignant tumor (chondrosarcoma) in the same region. Both lesions formed similar, painless bulges on the outline of the proximal aspect of the crus

Subsequently, the US image should be optimized, which ensures convenience and accuracy of the procedure (fig. 5A, B). In particular, one should remember about setting the depth parameter, level and number of foci as well as adjusting the grey scale to own preferences. In certain cases, when a needle is to be introduced in a direct vicinity of an artery, it is recommended to use the Doppler option. It is important to plan the needle path so as to reduce the risk of damaging the vessels, nerves and tendons (needle tip acts as a scalpel). One should also remember that there is no need for inserting the needle “straight” to the target site but it can be introduced “diagonally” – a longer but safer course^{(1, 2, 4, 5)}.

Fig. 5.

Example ultrasound image of the anterior and distal aspect of the forearm: A. image is not optimized; B. image is optimized

The assessment of a lesion, including its size, location and echogenicity (indirectly indicating its density), is of great significance for the selection of an optimal needle (fig. 6A, B). The length of the needle should be chosen based on the depth of the target structure (fig. 7A–D) and its thickness depends on the type of contents that are to be evacuated or introduced. Thicker needles are better for evacuation procedures (contents of joints, ganglia or bursae are frequently dense and gelatinous; hematomas may be partially organized with a large amount of fibrin). When thick needles are to be used, the skin may be additionally anaesthetized with a thin needle. A needle for administering medicines should be as thin as possible but its diameter depends on the type of the injected medication. For instance, hyaluronic acid requires the application of a thicker needle but Diprophos or Celestone may be injected with a needle of lower diameter.

Fig. 6.

Set of needles of various lengths and diameters

Fig. 7.

On the right hand side of the US monitor, there is a depth indication expressed in centimeters: A. hematoma after injury to the biceps femoris. B. forefoot with the intermetatarsal space; C. knee joint space at the level of the body of the medial meniscus; D. tibial nerve in the tarsal tunnel

We distinguish two ways of inserting the needle depending on its position in relation to the transducer: transverse (needle inserted at the middle of the probe) and longitudinal (needle inserted at the shorter edge of the probe). In the first case, the needle is visible as a shadowing dot and, as it passes through, shifting of tissues is observed. This method allows for needle manipulation (changing the angle just after insertion) without the need to alter the position of the transducer. The longitudinal insertion is undoubtedly much easier, especially for novices, since the monitor shows the shadow of the entire needle. However, losing its image each time the insertion angle is changed constitutes a disadvantage of this method. What is more, a continuous movement of the transducer is necessary when the position of the needle is modified^{(1, 2, 4–6)} (fig. 8A–C).

Fig. 8.

A. US image of a needle placed transversely to the longer transducer edge. B. Needle placed transversely to the longer transducer edge. C. Needle parallel to the longer transducer edge and its US image in the background

When administering medicines, one should bear in mind that they are released only through the middle part of the needle bevel. Therefore, when medicines are introduced to a narrow space, the needle tip should be placed in a structure located behind the distal wall of this space (in the case of the subacromial bursa, the needle tip should be placed in the region of superficial fibers of the supraspinatus tendon).

The first drops should be administered slowly so as to make certain that the needle is placed in the right localization. If expansion of tissues adjacent to the intended space is noticed, the depth of the needle should be modified^{(1, 3–5)} (fig. 9).

Fig. 9.

Measurement of the bevel of an injection needle (2.5 mm)

When the equipment has been prepared, access planned and needle chosen, the transducer may be put aside and the puncture site should be prepared in accordance with the principles of aseptics. A marker may be used to highlight the planned puncture site so as to avoid the necessity to search for it again (fig. 10). The position of a patient should be comfortable, stable and safe in case of fainting. The author in her own practice uses a lying position even if interventions are carried out in the arm. The physician should assume a position that guarantees stable support for the arm, elbow or wrist (this particularly refers to persons with trembling hands). The space for the transducer cable should also be taken into account – it should be easily maneuverable.

Fig. 10.

Intended puncture site highlighted with a marker

Common medicines used during ultrasound-guided interventions

Steroid-based medicines which are the most frequently administered by orthopedists are Celestone, Diprophos and Depo-Medrol (fig. 11). The presence of sepsis and local or intra-articular infections are direct contraindications to such steroids. Indirect contraindications include: periarticular osteoporosis, coagulopathy, anticoagulants (frequently, the only option of anti-inflammatory treatment is to administer steroids due to contraindications to oral NSAIDs) and joint instability (intra-articular administration of steroids may induce osteochondrosis and intensify instability by degeneration and weakening of the ligaments and joint capsule).

Fig. 11.

Medicines used for US-guided injections

Steroid-based medicines are a typical example of a “two-edged sword.” They are effective anti-inflammatory agents but cause a range of adverse reactions, such as:

1. Local reactions:

   • infections and in some cases, arthritis;
   • post-injection flare (severe pain which begins within several hours from injection, lasts 2–3 days and subsides spontaneously);
   • articular cartilage damage;
   • skin atrophy related to adipose tissue necrosis (persists for approximately 2 years) and discolorations (persist for approximately 1 year).
2. Systemic reactions:

   • facial flushing in approximately 15% of patients (lasts 2–3 days);
   • feeling of general malaise, headache;
   • increased catabolism;
   • increased risk of injury (due to intensified degenerative process) and infection – steroids should not be administered prior to planned physical effort or surgical procedures;
   • glucose metabolism disorder (in patients receiving oral hypoglycemic agents, a change of the therapy to insulin may be necessary). Fluctuating blood sugar levels may persist for 3–4 weeks following the injection.

Other medications that are frequently used in orthopedic indications include local anesthetics. Similarly to steroids, they are characterized by a range of contraindications, such as:

• anaphylaxis;

• treatment with MAO inhibitors or tricyclic antidepressants (simultaneous administration of local anesthetics may induce severe and prolonged arterial hypertension).

Maximum doses of local anesthetics equal 10 ml of 2% lignocaine or 20 ml of 1% lignocaine. The dose may be increased 2.5 times when epinephrine is also administered. One should remember, however, that local anesthetics exert toxic effects on chondrocytes and their toxicity increases when combined with epinephrine. Therefore, these medicines should not be administered into the joint. It is also mandatory to avoid their intravenous or intra-arterial administration, even in the slightest amounts. By doing so, one may induce neurological side effects (trembling, tremors, hyperventilation, apnea or convulsions) or cardiac reactions (arrhythmia or circulatory collapse)⁽⁷⁾.

Conclusions

Ultrasound guidance while inserting the needle allows for a safe medicine administration and evacuation of fluid contents. It improves the efficacy of such procedures by ensuring accurate needle insertion in the target site and subsequent medicine injection or evacuation of fluid contents. Thus, it reduces the duration of treatment and minimizes pain (procedures are usually performed with a single puncture). There is no need for “blind” lesion seeking and administering medicines into adjacent tissues is avoided. Ultrasound-guided interventions should become standard procedures in each treatment room.

Conflict of interest

Author does not report any financial or personal links with other persons or organizations, which might affect negatively the content of this publication and/or claim authorship rights to this publication.