a 69 year old male patient , with height at 172 cm and weight at 70 kg , visited the hospital with gait abnormality in his right leg and pain in the pelvic joint area , which had continuously continued since its occurrence two years ago . the patient had a history of undergoing low anterior resection , radiation treatment , and chemotherapy four years prior for rectal cancer , and was taking insulin and oral hypoglycemics for diabetes . since two years ago , the patient 's leg could not be straightened properly when walking and pain in the pelvic area occurred when there was sudden movement . he had visited pain clinics , rehabilitation clinics , neurology , and orthopedics , but did not receive any specific diagnosis and had endured with the aid of physical and drug treatments . the degree of pain was 4 - 5/10 in the visual analog scale ( vas ) , and the symptoms were pain in the right pelvic joint when walking , and when lying down , the pubic area felt tight and painful when the leg was completely straightened , with pain subsiding when the leg was bent . during the physical examination , the straight leg raising test was 90/90 , but there was pain in both thighs , and the patrick test indicated that both sides were positive . the ganslene test was also positive in both sides , but the pain was worse in the right . there was tenderness in the spinous process of l3 , and there were no tender points in the facet joints . the patient also complained of tenderness in sacroiliac joints , gluteus medius , and piriformis . in the magnetic resonance image ( mri ) , there were no metastasis or recurrence observed , but the disc between l2 and 3 had been herniated to the right and was pressing the right psoas ( fig . hence , the gait abnormality and pain was considered to be caused by the laterally herniated intervertebral disc that compressed the right psoas muscle , and so a right psoas compartment blockade was performed . first , the patient was laid prone and the skin was sterilized . under c - arm guidance , the transverse processes of the l3 were confirmed and an approach was made with a 22-g tuohy needle ( arrow , arrow international inc . was the location after the psoas muscle was observed with the contrast medium , which was shown when 0.25% levobupivacaine ( chirocaine , abbott , elverum , norway ) 10 ml and triamcinolone diacetonide 5 mg were injected ( fig . the patient stated that there were no effects from the drug therapy received at another hospital , so in order to discern the effects of the blockade no other particular oral medication was prescribed . when the patient visited the outpatient clinic one week after the procedure , periods without pain had continued for two to three days and gait abnormality had also disappeared during this period , but at the time of visit , a pain of vas 5/10 was experienced by the patient . hence , it was decided that the psoas compartment blockade was effective , so it was performed three times in two week intervals . as a result , the patient has shown improvements in pain of about vas 3/10 , so we are still monitoring his progress . the psoas muscle is the muscle involved with the curve of the pelvis and spine , which starts at the thoracic vertebrae to connect with the lower vertebral body and transverse process . when standing , it pulls the spine forward , while keeping the balance of the body when sitting , so it has an important role during walking motion . therefore , when the psoas muscle continuously contracts from injury or stress , the vital dynamics of the pelvis , lumbar , and even the cervical vertebrae can be disturbed . this incongruity can cause pain in the lower back , pelvis , buttocks , and the femoral region . also , there could be a transformation in the hip joint curve , and as a result thus , when there is a problem in the psoas muscle , it can trigger a distinctive psoas gait , where the patient drags their leg while walking as the leg can not be strongly pushed forward . the differential diagnosis for patients with these symptoms can consider infectious diseases , such as an abscess in the psoas muscle , hemorrhagic lesions , such as hematoma , and the metastasis of cancer . an abscess in the psoas muscle is not common , but is recently showing an increasing trend . uncontrollable diabetes can be an important preceding factor , and symptoms , such as fever , pain in the side or hip area , and limitation in movement of the hip joints appear . hemorrhagic lesions , such as hematomas , are known to occur more in patients who are either taking antiplatelet agents or anticoagulant treatment , or patients with blood coagulation disorders . it is not common for cancer to spread to the psoas muscle , but for patients with a history of cancer , it must be taken into consideration that the psoas compartment can be a channel for the tumors to directly infiltrate the retroperitoneal , skeletal muscles , and pelvis . there is also a report that , in a patient with rectal cancer , a biopsy performed in suspicion of an abscess in the psoas muscle , revealed the metastasis of cancer . treatment methods can be different for these diseases , such as internal medicine and surgery , so an accurate diagnosis is important . after differentiating the suspected diagnosis to a certain degree , through medical history , physical examination , and blood tests , the case of lateral disc herniation is where the disc is herniated to the side of the root foramen , toward the outside of the spinal canal . lateral disc herniation is a lesion that is easily missed because it is difficult to observe in a mri image . even in our case , the reinforced image of t2 did not show a herniated disc or compression of the nerves ( fig . 1c ) , so if lesions in the psoas muscles had not been suspected , diagnosis would have been delayed under the false judgment that there were no disc problems . there are not many studies regarding the relationship between lateral disc herniation and the psoas muscle . however , there is a study that analyzes the connection between the sciatica and the reduced sectional area of the psoas muscle resulting from lateral disc herniation . in addition , a case study reporting similar symptoms to meralgia paresthetica that results from lateral disc herniation is also available . since the psoas muscle is adjacent , through fibrous attachments , to all discs in the lumbar excluding the discs between l5 and s1 , lesions in the lumbar disc can affect the fascia disease of the psoas muscle . treatment regarding myofasciopathy , caused by the compression of the psoas muscle , is based on conservative treatment , but there is no proven definite treatment as of yet . the authors thought of the mechanism for pain relief and gait abnormality when a psoas compartment blockade was performed using steroids . the psoas compartment is the space located between the psoas muscle and quadrates lumborum , and is surrounded by the psoas muscle and its fascia in the front , the lumbar , and the transverse process of the lumbar , ligament , muscle , and quadrates lumborum in the back . within this compartment , the lumbar plexus , the ventral ramus of the sacral plexus , iliohypogastric nerve , ilioinguinal nerve , genitofemoral nerve , lateral femoral cutaneous nerve , femoral nerve , obturator nerve , and parts of the sciatic nerve pass through . the psoas compartment block is generally performed on the l3 or l4 disc and serves to block the lateral femoral cutaneous nerve , femoral nerve , and the obturator nerve , so the block is also known as the posterior lumbar plexus block . the iliohypogastric , ilioguinal , and genitofemoral nerve can be further blocked if medication is expanded toward the cephalad within the fascia . as in this case , where the psoas compartment block was performed on l3 , the steroid and local anesthetic is spread to the psoas muscle fascia and nerve within the psoas compartment , which relieves pain in the psoas muscle and hip joint , and results in the improvement of gait abnormality . the amount of steroid used in the psoas compartment block is not determined in general , but 40 - 80 mg of triamcinolone diacetonide is used for each procedure when performing the epidural block . however , in the case of the psoas compartment block , the fascia is located adjacently so muscle atrophy can occur from the steroid , and since the patient in this case had diabetes as an underlying disease , only 5 mg of triamcinolone diacetonide was used in the initial procedure . it was found that using local anesthesia , coupled together with steroids , is more effective and also possesses long - term pain relief . these effects are thought to be from the steroid suppressing the hypothalamus , pituitary gland , and the adrenal gland . the patient in our case had a history of rectal cancer and had diabetes as an underlying disease , so an abscess in the psoas muscle or metastasis was suspected . however , the suspicion proved to be incorrect since the symptoms had gradually occurred for two years and there were no signs of infection . the mri results showed compression of the psoas muscle by a laterally herniated disc , so pain was relieved and gait abnormality improved through the psoas compartment blockade . in these kinds of patients , detailed history taking , physical examination , and imaging should be performed for accurate diagnosis and proper treatment , with the psoas compartment blockade now being able to be considered as another treatment method .
a psoas compartment block has been used to provide anesthesia for orthopedic surgical procedures and analgesia for post - operative pain . 
 currently , this block is advocated for relieving pain in the lower extremity and pelvic area resulting from various origins . 
 we report a case of a 69-year - old male patient who had gait abnormality with posterior pelvic and hip pain , which were both aggravated by hip extension . from the magnetic resonance image , 
 the patient was found to have a laterally herniated intervertebral disc at the l2/3 level , which compressed the right psoas muscle . 
 this was thought to be the origin of the pain , so a psoas compartment block was performed using 0.25% chirocaine with triamcinolone 5 mg , and the pain in both the pelvis and hip were relieved .