a twenty year - old female ( 50 kg , 160 cm ) was referred to our pain clinic due to left ankle pain , 2 years after a pedestrian traffic accident , and after prior failed attempts at pain control and functional rehabilitation through physical therapy and medical management . prior to this injury the patient suffered throbbing , tearing - apart like , and stabbing pain around her left ankle with marked allodynia on her left sole with 8/10 of an 11-pointed numerical rating scale ( nrs ) pain score in severity . we evaluated the patient using a standardized assessment protocol for diagnosing crps as described by the budapest research criteria , and diagnosed her with crps type i affecting her left foot . apart from oral medication such as antidepressants , anticonvulsants , and tramadol , she has received an lsgb on the left side at every monthly follow - up . after the lsgbs , she has experienced a significant reduction in pain from 8 to 5 or 6 ; however , during fluoroscope - guided lsgbs , she could not tolerate procedure - related pain due to the needle tip touching her l3 vertebra 's bony cortex and periosteum . in an attempt to avoid the pain during the lsgb , we planned to perform the lsgb under ultrasound guidance using fluoroscopic confirmation . a portable ultrasound image device ( hd11xe , koninklijke philips n.v . the patient entered the operation room with a 24 g intravenous route , and non - invasive blood pressure and pulse oxygen saturation level were continuously monitored during and after the procedure . she was placed in a prone position with a pillow under the lower abdomen and iliac crest to reduce lumbar lordosis , and temperature probes were attached to both soles using transparent patches ( teraderm , 3 m healthcare , st paul , mn , usa ) . after sterilizing and draping the skin around the puncture sites , both soles were also covered to stabilize temperature . the lsgb was performed at the upper third of the l3 vertebra without any pre - medication . for performing the ultrasound - guided lsb , the target vertebra level ( the l3 vertebra was identified by locating the lumbosacral junction ( l5-s1 gap ; fig . 1 ) , on paramedian sagittal scanning and counting was done cranially by numbering the lamina and transverse processes of the l5 , l4 , and l3 vertebrae . after marking the level of the l3 vertebra , the transducer was rotated transversely to obtain a short - axis view showing the transverse process and facet joint . then , the modified transverse scan of the lumbar paravertebral region through lumbar inter - transverse space was obtained by positioning the transducer at 4 - 6 cm lateral to the midline in the transverse orientation at the l2-l3 or l3-l4 intervertebral level ( fig . the transducer was also directed medially to insonate the anterior fascia of the psoas major muscle , the target of the needle tip , through the lumbar inter - transverse space . color doppler was utilized to determine the presence of vascular structures and to plan needle trajectory . prior to needle insertion , we visualized the lower pole of kidney , which is usually located approximately at the l3 level , the right kidney being slightly lower than the left . the insertion point of the needle was 8.8 cm lateral to the l3 spinous process . the skin entry point was infiltrated using 1% lidocaine . a curved tip 21 g , 15-cm chiba needle ( cook inc . , bloomington , in , usa ) was then advanced toward the anterolateral edge of the target vertebral body using a posterolateral approach . the needle was inserted from a lateral to medial direction using in - plane technique so as to monitor it in real time as it was advanced , using hydrolocalization technique with 1.5 ml of normal saline . the target of the needle tip was the anterior fascia of the psoas major muscle close to the paravertebral space ( fig . 2 ) . after evaluating the location of the needle tip under us and verifying negative aspiration for blood or csf , 3 ml of contrast dye was administered incrementally to exclude vascular injection by a c - arm image intensifier ( zhiem vsion r , ziehm imaging , nuernberg , germany ) on the anteroposterior and lateral view , followed by 10 ml of 0.25% levobupivacaine ( fig . 3 and 4 ) . as an index of the successful lsgb , skin - surface temperatures were monitored with small , adhesive thermocouple probes attached bilaterally to the plantar surface of the feet using transparent patches . temperatures were measured and recorded from the time of the administration of the local anesthetic onwards . the temperature of the left sole rose from 29.3 to 33.0 over five minutes , an increment of 0.1 per 10 seconds . a rise in temperature of as much as 2 on the left sole seemed to be an adequate sign of the success of the lsgb , therefore , the patient was sent to the recovery room and then was discharged without any adverse events . an lsgb under a fluoroscope is the most generally used method , due to its convenience and accuracy in confirming the needle tip location or intravascular injection ; however , the success rate of fluoroscopic lsgbs has not been satisfactory , ranging from 67% under fluoroscope guidance to 83% under ct - guidance . reports that radiation exposure in seconds raged from 7.4 - 12.5 seconds during the fluoroscopy guided lsgb , and nordmann et al .   estimated the radiation dose during a ct guided lsgb to be between 1.5 and 3.0 msv . this equates to approximately one year 's exposure to natural background radiation in the uk , or the equivalent of about 15 - 30 chest radiographs . as the patient in this case was a young female , and she needs repetitive lsgbs , it might be a necessary to minimize radiation exposure . since the lumbar sympathetic chain is located just anterolateral to the vertebral body , the abdominal aorta and inferior vena cava , located anterior to the vertebral body , are relatively vulnerable to penetration . because of the poor visualization of the deep tissues and inability to confirm the intravascular injection , the lumbar sympathetic block under ultrasound guidance has only been reported once in 1992 as a new technique . as the research dealt also with cpb , the figures and the description of the technique was focused more on the cpb and was insufficient for the lsgb , and there have not been any following literature about ultrasound - guided lsgbs since . although us - guided injection with fluoroscopic confirmation has shown similar accuracy and efficacy to fluoroscopy alone for various spinal blocks , no study has sought to compare these techniques for the lsgb , or determine which technique has greater benefits for efficacy and safety during lsgbs ; therefore , further study will certainly be needed in this field . a previous study reported that the lumbar paravertebral space including the psoas muscle , an anatomical key for the lsgb , was visualized on us in approximately two - thirds of the patients . therefore , we expect that direct visualization of the relative positions of the needle tip in relation to the anterior fascia of the psoas major muscle in the paravertebral space under us - guidance would have similar success rates to fluoroscope - guided lsgbs , along with shortening the procedure time and decreasing procedure - related discomfort which may usually be caused by a needle tip touching the bony cortex of the l3 vertebral body during the fluoroscope - guided lsgb . it is possible , in us - guided lsgbs , to take in real time visualization of the internal organs like the kidney and to easily avoid damage to the internal organs . therefore we can make the insertion point of needle into the skin more lateral , and reduce the contact pain of the needle striking the bone . certainly , we need further study to prove the benefits of the us - guided lsgb with fluoroscopic confirmation . the frequent use of usg for regional anesthesia and pain procedures has familiarized its use among practitioners . us provides a reliable setup in localizing the anterior fascia of psoas muscle , as well as the relative position of the needle with respect to surrounding tissues . we expect that the us - guided lsgb can be implemented successfully in daily outpatient clinical settings by highly trained pain physicians .
the lumbar sympathetic ganglion block ( lsgb ) is widely used for diagnosing and treating sympathetically maintained pain disorders . 
 the lsgb has been conventionally carried out under fluoroscopy or computed tomography guidance . however , as ultrasound technology improved , ultrasound - guided interventions have been expanding their territory to deeper structures . 
 ultrasound guidance provides many benefits including protecting vascular injection , shortening procedure time in some cases , and reducing the emission of radiation . in this report 
 , we describe a successful case of a us - guided lsgb without major complications . 
 we expect that us - guided lsgbs can be implemented and furnished in the daily outpatient clinical setting by highly trained pain physicians .