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Thứ Năm, 27 tháng 9, 2012

SIÊU ÂM ĐIỀU TRỊ VIÊM GÂN VÔI HOÁ CHÓP XOAY


Sonographically Guided Lavage Aspiration Technique
 

The patient is positioned such that the calcification to be treated is well visualized and amenable to needle placement and that both the patient and physician will be comfortable throughout the procedure. Depending on the

calcification location, particularly within the supraspinatus tendon and deep to the overlying acromion process of the scapula, it may be necessary to experiment with various armpositions of the patient to achieve this goal. Generally, the procedure is performed with the patient in the lateral decubitus or supine position for supraspinatus and infraspinatus calcification and in the supine position if the subscapularis tendon is the target.

 

A high-resolution linear probe (10–17 MHz) is used for this procedure, as the target calcification is usually very superficial. A 25-gauge needle is used for local anesthesia, and a 16- to 18-gauge needle is generally used for the lavage aspiration. Although some authors have advocated a smaller needle size (22 gauge), 20 in this author’s experience, a larger needle allows a faster andmore complete evacuation of calcium. Although others also advocate a 2-needle approach, and excellent results have been achieved with this method, this author has not found that approach to substantially improve calcium removal or to decrease the procedure time.
 
A recent study of 462 patients suggests that warming the lavage fluid may help improve dissolution of calcium and shorten the procedure time, which may prove to further optimize this technique.

However, this large study did not show a significant difference in patient outcomes as determined by visual analog scale scores between the two groups.

In preparation for the lavage aspiration, a series of syringes are prepared (3–6, depending on the size of the calcification) containing a mixture of saline and an anesthetic. This author favors a blend of 70% sterile saline and 30% lidocaine, 1%. A syringe containing an additional anesthetic (0.25% bupivacaine HCl) and cortisone (triamcinolone acetonide or methylprednisolone acetate) is also prepared for the subacromial-subdeltoid bursal injection that concludes the procedure, with the bupivacaine providing relief of postprocedure discomfort for several hours.

Continuous sonographic visualization of the calcification and needle is necessary throughout the procedure.

A liberal amount of anesthetic is administered subcutaneously, within the deeper soft tissues and within the subacromial-subdeltoid bursa, being sure that no air is introduced into the soft tissues or adjacent subacromial-subdeltoid bursa, extending from the skin entry site to themargin of the calcification along the expected path of lavage needle placement. If air is injected and is superficial to the target calcification, particularly within the subacromial-subdeltoid bursa, the calcification may be entirely obscured, and the proceduremay need to be postponed until the air is resorbed, which may take several days. With appropriate local anesthetic administration, the procedure is generally well tolerated with only mild discomfort. With continuous sonographic visualization, the 16- or 18-gauge needle is advanced into the epicenter of the calcific focus with a single puncture (Figure 3). Using the syringes filled with the anesthetic/saline  mixture noted above, intermittent plunger pressure and release are performed until a cavity forms within the focus of calcification (Figure 4). At this point, swirling of echogenic material (calcium) will be seen within the cavity, and with plunger release, this calcific material will decompress into the syringe. If more than a single puncture is made into the lesion, the lavage material may decompress through this additional hole in the calcific focus, and the yield of calcium removed will be diminished.
 

As large amounts of calcium fill the syringe, exchange is made for new clear syringes until no further calcification may be removed. The calcific material removed will be seen to layer within the dependent portion of the syringe (Figure 5). At this point in the procedure, any remaining calcification along the wall of the original focus is fenestrated using the needle. If additional foci of calcification are present, these are treated in the same manner. At the conclusion of this process, any remaining calcium fragments too small for lavage are also fenestrated with the needle. Finally, the mixture of anesthetic and corticosteroid described above is injected into the adjacent subacromial-subdeltoid bursa, which will provide considerable pain relief over the next several weeks to months as additional calcific material decompresses into the bursa from the involved rotator cuff tendon.
 
 
 

Although follow-up radiographs are not routinely obtained, they may show a rapid and marked decrease in the amount of calcification remaining within the tendon. In patients with recurrent or residual pain after therapy, subsequent sonographic examinations may be performed to assess the degree of calcification within the tendon or subacromial-subdeltoid bursa. Patients in this group may often be effectively treated with a sonographically guided bursal cortisone and anesthetic injection.

 

Conclusions

Calcific tendinosis of the rotator cuff is a commonly diagnosed entity that is responsible for a great deal of patient pain and limitation of mobility. Although radiographs remain the mainstay of initial calcium visualization and diagnosis, sonography can localize the calcification to the specific tendon involved, assess the entire rotator cuff for tears or tendinosis, and also evaluate the adjacent biceps tendon and subacromial-subdeltoid bursa for concomitant abnormalities. Finally, diagnostic sonography provides the means by which this condition can be safely treated by the percutaneous technique described above. This technique quickly removes and fragments the problematic calcification with a low incidence of complications, and multiple studies have shown an excellent clinical response in most patients. Lavage aspiration with sonographic guidance has thus become the optimal modality for effective treatment of this painful condition.
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