Should lidocaine be avoided for local anesthesia in radiation synovectomy?
OBJECTIVE
Leakage is of major concern when performing radiation synovectomy. Although post-treatment immobilization was provided, extra-articular leakage of radioactivity has occasionally been observed in patients receiving local anesthesia in the course of radiation synovectomy. This study was performed to uncover any unfavourable effect of lidocaine on stability of (166)Ho-FHMA (ferrum hydroxide macroaggregate).


METHODS
The radiopharmaceutical was investigated in bovine serum albumin (BSA) solutions (5, 10 mg/ml) at pH 6, 7 and 8. Furthermore, the tracer was incubated for 0, 2, 24, 48 and 120 hours in synovial fluid. In both series the influence of lidocaine-HCl 2% (500, 1000 microl) has been evaluated.


RESULTS
In BSA test solutions, amount of lidocaine added [df(2), F=7.82, p-level: 0.00] and pH [df(2), F=7.82, p-level: 0.00] significantly influenced in vitro stability of (166)Ho labeled FHMA (n=72). This finding was confirmed in synovial fluid [df(2), F=3.82, p-level: 0.03] (n=60).


CONCLUSIONS
In an experimental design mimicking normal and inflammatory conditions in the joint, addition of a few milliliters of lidocaine-HCl followed by a shift towards lower pH-values in synovial fluid may endanger stability of the carrier-tracer complex (166)Ho-FHMA and thereby enhance extra-articular leakage.
Schweeger
I
I
Department of Nuclear Medicine, University of Vienna, Vienna, Austria.
Pirich
C
C
Ofluoglu
S
S
Sinzinger
H
H
D000779:Anesthetics, Local / Q000737:chemistry; D004355:Drug Stability; D005119:Extravasation of Diagnostic and Therapeutic Materials / Q000517:prevention & control*; D006801:Humans; D007592:Joint Diseases / Q000532:radiotherapy; D008012:Lidocaine / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry* / Q000627:therapeutic use; D012710:Serum Albumin, Bovine / Q000737:chemistry*; D013582:Synovial Fluid / Q000737:chemistry*
D000779:Anesthetics, Local; C496168:Ho-FHMA; D009942:Organometallic Compounds; D012710:Serum Albumin, Bovine; D008012:Lidocaine