a 40-year - old man sought evaluation of a 4-year - history of perianal and perineal pain , including the testes and penis . in this patient , there was no notable history of trauma or disease . on mri and ct scans , which included the abdomen and pelvis , there were normal findings . at the time of admission , the patient had a visual analog scale ( vas ) of 8/10 .
the patient had the persistent presence of pain , which was characterized as bursting and explosive .
due to the presence of pain , the patient could not assume a sitting position for more than 5 minutes .
four years before the initial onset of pain , the patient had been working as aresearch staff in the us . at the time , the patient sought evaluation in a urology department under the assumption that the condition originated from the prostate gland .
following evaluation , the patient was considered normal without a discernible etiology for the pain .
the patient was therefore transferred to a pain clinic , where the patient was given oral medications ( gabapetin 1,800 mg / day and methadone ) in an outpatient setting .
however , these procedures had no effect in reducing the pain . in early february 2007 ,
the patient sought evaluation in an outpatient clinic in the us due to aggravation of the pain in a lying position , and underwent blockage of the ganglion impar ; the vas decreased from 8/10 to 4/10 . because the effect was sustained for approximately 1 day , the patient could not ambulate for 2 months . during this period ,
thereafter , the patient underwent blockage of the ganglion impar on two occasions . following this ,
the pain decreased to a vas of 4/10 . when the pain was severe , however , it was a vas of 8/10 .
every 3 months , the patient underwent blockage of the ganglion impar 4 times with the use of steroids 40 mg each , 4 times . in september 2008 ,
the patient was recommended to undergo the blockage of the ganglion impar by radiofrequency ablation .
a diagnostic blockage was first performed using 0.5% bupivacaine 2 ml because the patient was concerned about the destruction of the nerve ganglion .
the patient was monitored clinically , and 3 months later , the vas of 8/10 had decreased to 5/10 .
approximately 1 week later , however , the pain recurred with a vas of 7 - 8/10 .
the severity of pain was not significantly different from the pain which existed prior to treatment .
the patient was therefore motivated to have blockage of the ganglion impar using bont - a .
for blockage of the ganglion impar , the patient was placed in a prone position .
this area was chosen as a puncture point . using a c - shaped image intensifier ,
a 22 g , 10 cm block needle in which the terminal part was bent at an angle of 30 degrees was advanced to a distance of 6 cm .
following infusion of 2 ml of contrast media , the lateral and anterior - posterior views were evaluated ( fig . 1 , 2 ) . based on the spread pattern of the contrast media , the infusion was performed with a concomitant use of 0.5% bupivacaine 1 ml and bont
- a 80 u. the vas of 7 - 8/10 decreased to 3/10 , but the vas increased to 5/10 two months following the blockage .
accordingly , with the use of bont - a , 2 months following the blockage , the ganglion impar was blocked using 0.5% bupivacaine 2 ml and bont - a 100 u. when the patient underwent blockage using bont - a again , the vas decreased to 2/10 and this was maintained for 6 months .
the patient perceived the presence of perineal pain ( a vas of 5/10 ) during the sexual intercourse , which led to the third session of blockage of the ganglion impar at the same dose , which diminished the vas to 2/10 . at present , 3 months following the last treatment , other than perineal pain ( a vas of 4/10 ) , the patient has had no problems in performing activities of daily living and work , including sitting and walking .
the patient has maintained a vas of 2/10 . to evaluate the degree of disability due to chronic pain during activities of daily living ,
the pdi has seven categories , such as activities associated with family / home responsibilities , recreation , social activities , occupation , sexual behaviors , self - care , and life - support activities , and scores are given with a scale ranging from 0 ( no disability ) to 10 ( total disability ) .
according to the pdi , scores were 10 , 9 , 10 , 10 , 10 , 7 , and 1 , respectively , prior to treatment . following the third session of blockage of the ganglion impar using bont - a ,
the pdi scores were greatly improved to 2 , 2 , 2 , 2 , 4 , 3 , and 0 , respectively .
currently , the patient has had a satisfactory outcome and is receiving follow - up observation .
the etiology for cpp may include benign causes , such as chronic prostatitis and chronic proctitis , as well as malignant causes , such as carcinoma of the pelvic organs .
the ganglion impar is a solitary retroperitoneal structure at the level of the sacrococcygeal junction and it marks the termination of the paravertebral sympathetic chain .
the ganglion impar receives the nerve fibers from the sympathetic and parasympathetic nervous system , which are present in the lumbar and sacral regions , and it is responsible for the distribution of sympathetic nerve fibers in the organs around the pelvis or reproductive organs . the sympathetic nervous system is associated with myriads of pain syndromes . a blockage of the sympathetic nerve fibers has therefore been used to alleviate pain .
in addition , blockage of the ganglion impar has been used extensively to treat anal or perianal sweating , rectal tenesmoid pain , and coccygodynia [ 1 - 3 ] . there
exist various methods to block the ganglion impar , such as local anesthetics , concomitant use of local anesthetics and steroids , alcohol or phenol , and neurolysis by radiofrequency ablation .
botulinum toxin is a potent neurotoxin which is extracted from the exotoxin of clostridium botulinum , which proliferates in contaminated foods and triggers the occurrence of food poisoning .
bont - a binds to the presynaptic nerve endings and blocks the secretion of acetylcholine , thus causing a flaccid muscle paralysis .
this chemodenervation transiently occurs , and while minimizing the systemic side effects , it persistently reduces or abolishes the activities of muscles , sweat glands , or muscles of contraction for several months . accordingly , the use of bont - a is effective in treating diseases associated with an excessive contraction of the muscles , including strabismus , blepharospasm , unilateral blepharospasm , and abnormal muscle tension in the neck .
attempts have also been made to treat various types of headaches , lower lumbar pain , myofascial pain syndrome , and crps with bont - a [ 6,10 - 12 ] .
recent studies have suggested that bont - a has an effect on the secretion of neurotransmitters which are involved in the recognition of pain secondary to the analgesic effect due to muscle relaxation [ 6 - 8 ] .
analgesic mechanisms of bont - a can mainly be divided into peripheral , spinal , and cerebrocortical mechanisms . according to cui
, the peripheral mechanisms are of interest based on the finding that the subcutaneous solar administration of bont - a had a significant analgesic effect in an experimental model of pain induced using formalin in rats . in cases of neurogenic inflammation , with the initiation of secretions of substances , such as substance p , cgrp , and glutamate , local
vasodilation , plasma leakage , and the destruction of mast cells occur . owing to these inflammatory events , bradykinin , atp , histamine , and serotonin , which are known to provoke hypersensitivity of peripheral nociceptors ,
it has been reported that bont - a blocks the early stage of these chain reactions of neurogenic inflammation and thereby reduces pain .
park et al .   clarified that bont - a effectively reduced mechanical , cold allodynia in an animal experimental model of neuropathy .
, an intradermal injection of bont - a had a direct analgesic effect in patients with local chronic neuropathy associated with allodynia .
these reports provide a theoretical basis for the availability of bont - a for the treatment of neuropathies .
the activity of central pain receptors immediately after pain stimulation can be measured based on the expression of c - fos , genes associated with the early expression of pain .
bont - a blocks the secretion of neurotransmitters which are involved in the pathophysiology of neurogenic inflammation , such as glutamate , secreted from the primary afferent pain receptor fibers .
bont - a therefore reduces the extensive activity of dorsal horn neurons of the spinal cord , which has been confirmed based on the decreased expression of c - fos .
bont - a is involved in the blockage of secretion of the above - mentioned inflammatory mediators and suppresses the expression of c - fos occurring immediately after pain sensation .
it can therefore be concluded that bont - a suppresses peripheral sensitization , and this leads to central desensitization . as described herein , in addition to the peripheral and spinal cord effects of bont - a ,
the effects on the central nervous system have also been examined in many studies . with respect to the finding that bont - a causes alterations in the sensory pattern via the neural axis , including the cerebral cortex , it has been reported that major mechanisms altering the overall recognition of pain by bont - a originate from the neuroplastic reorganization of excitatory and inhibitory balances . through experimental results that bont
- a has an anti - nociceptive effect via axonal transport to the central nervous system following peripheral injection , it has been demonstrated that the central nervous system is involved in the mechanisms by which bont - a reduces pain .
alcohol and phenol , which have been commonly used for neurolysis , can not accurately predict drug spread , and therefore these agents can not block nerves selectively . alcohol and phenol cause irreversible destruction .
furthermore , alcohol and phenol have been reported to induce novel pain . in cases of pain in which radiofrequency ablation is used , there exist specialized equipment , such as an electrostimulating device and a minute controller .
there is a lower possibility that complications might occur in cases in which neurolysis is performed .
the size and location of lesions can be controlled . of the methods for blocking ganglion impar
in which ganglion impar is blocked , however , an approach is commonly made via the anococcygeal ligament .
because a cannula has a linear form , an accurate approach can not be made to the ganglion impar .
accordingly , as an alternative method to radiofrequency ablation , blockage of the ganglion impar was performed using bont - a .
performed blockage of lumbar sympathetic ganglia in patients with crps , and compared treatment outcomes between the group in which 0.5% bupivacaine 10 ml was used alone and a group in which concomitant use of 75 u bont - a and 0.5% bupivacaine was attempted . as a result ,
the decrease in vas was markedly greater and the analgesic period was prolonged in the group in which bupivacaine 10 ml and 75 u bont - a was concomitantly used for blockage of the ganglion impar .
this is an example demonstrating the sympathetic nerve block effect of bont - a based on clinical studies rather than animal experiments , which provides a basis for the sustained effect and the decrease in vas as compared with cases in which the patient underwent blockage of the ganglion impar using conventional types of local anesthetics .
accordingly , as shown in animal experiments in which formalin was used , the mechanism of bont - a is not referred to as direct destruction of nerve fibers , rather based on blockage of pain - controlling neurotransmitters . a reversible , transient analgesic effect
is considered one of the advantages in the current case , and . in agreement with an experimental animal reports by kim et al .  
in which bont - a caused no marked histopathologic changes as compared with cases in which blockage was done using alcohol or phenol , and the effects were persistently present for > 1 month .
in the current case , the use of bont - a for blockage of the ganglion impar was safer than neurolysis based on the previous types of chemical or high - frequency ablation .
the effects were superior to cases in which local anesthetics were solely used , and the analgesic period was prolonged .
based on these advantages , bont - a is proposed as a new method for blocking the sympathetic nervous system . aside from these advantages , there are also disadvantageous in that bont - a can pose a safety issue . bont
- a is rather expensive and requires serial use . in association with this , in adults weighing 70 kg in which the ld50 of bont - a amounts to 3,000 u , the common clinical dose is at most 25 - 100 u and it can therefore be considered very safe .
bont - a is used at 3 - 6 month intervals , and the proportion of antibody formation has been reported to be < 4% .
the problem that the drug effect is lost due to the formation of antibodies following repeated use can also be resolved .
it it has been reported that the use of bont - a reduces the amount of analgesic drugs , the need for treatment , and the length of hospital stay associated with the side effects of drugs .
together , these features may overcome the cost associated with bont - a . because the number of cases in which bont - a has been used for the blockage of ganglion impar is limited , further clinical studies and application are needed .
 chronic perineal pain is an often encountered problem , which produces a great degree of functional impairment and frustration to the patient and a challenge to the treating physician . 
 the reason for this problem is that the region contains diverse anatomic structures with mixed somatic , visceral and autonomic innervations affecting bladder and bowel control and sexual function . 
 a blockade of nociceptive and sympathetic supply to the perineal region , supplied through the ganglion impar has been shown to benefit patients with chronic perineal pain . 
 several options to this block have been described that chemical neurolysis , radiofrequency ablation etc . 
 although the analgesic effect of botulinum toxin type a ( bont - a ) has long been considered secondary to its action for muscle relaxation , bont - a also affects the release of the neurotransmitters that are involved in pain perception . 
 we describe a patient who was successfully given ganglion impar block with bont - a . 
CASE REPORT
DISCUSSION