psoas abscess is characterized by infrequent incidence , insidious onset , and nonspecific clinical features , which can lead to misinterpretation and delayed diagnosis ; thus , it is difficult to clinically diagnose psoas abscess1,5 ) . here , we present a rare case of tuberculous spondylitis and a large abscess in the left psoas muscle that occurred after spinal surgery for an acute burst fracture of the second lumbar ( l2 ) vertebral body caused by a traffic accident . moreover , the first radiological examination revealed some unusual findings that could have possibly indicated abscess before his spinal surgery .
in may 2009 , a 44-year - old man was transferred to our hospital for lower back pain after he suffered from a blunt trauma in a pedestrian traffic accident .
his medical and surgical histories were unremarkable . neurological examination and chest radiology revealed no abnormalities .
laboratory evaluation revealed a erythrocyte sedimentation rate ( esr ) of 48mm / hr ( normal range , 0 - 10mm / hr ) and c - reactive protein ( crp ) of 239.52mg / l ( 0 - 5mg / l ) , and a normal wbc count of 7740/l ( 4000 - 10,000/l ) .
lumbar computed tomography ( ct ) scan with bone window settings revealed a burst fracture of the l2 vertebral body with displacement of a posterior fragment into the spinal canal ( fig .
lumbar magnetic resonance imaging ( mri ) revealed acute burst fracture with retropulsion of the posterior bone fragment at the l2 vertebral body and acute compression fracture of the l1 vertebral body ( fig .
he underwent posterior reduction , transpedicular screw fixation , secondary anterior thoracoscopic decompression , and anterior reduction that was accomplished with a distractible cage and a modular anterior construct systemthoraco - lumbar ( macs - tl ) plate ( aesculap , tuttlingen , germany ) ( fig .
the patient had no postoperative complications and was discharged on the 45 postoperative day . until july 2010 ,
the patient 's clinical condition was satisfactory ; thereafter , he exhibited a gradually enlarging swelling in the left flank , associated with pain extending up to the left thigh , and urinary incontinence .
his esr was 120mm / h ; crp level , 59.94mg / l ; blood urea nitrogen ( bun ) level , 28.1mg / dl ; and serum creatinine level , 1.77mg / dl .
abdominopelvic ct revealed the presence of a large abscess in the following sites : left psoas muscle , lower pole of the left kidney , and posterolateral abdominal wall .
2 ) . abscess drainage and irrigation and partial nephrectomy through the previous surgical route were performed under general anesthesia .
the abscess and surrounding soft tissue samples yielded positive results in the acid - fast bacilli ( afb ) culture and polymerase chain reaction ( pcr ) for mycobacterium tuberculosis complex .
the patient received antituberculous chemotherapy , consisting of isoniazid , rifampin , pyrazinamide , along with pyridoxine supplements , on a daily basis . in november 2010
the patient was transferred to the urological department for treatment of the left ureteral stricture .
initially , the predominant pathogen was mycobacterium tuberculosis , which caused psoas abscess through either hematogenous spread or direct extension from vertebral osteomyelitis of the lumbar spine ( pott 's disease ) . with the decline of mycobacterium tuberculosis as a major pathogen of psoas abscess in developed countries ,
the condition was mostly detected secondary to diseases of the digestive tract , with other pathogens such as staphylococcus aureus gaining more dominance in the pathogenesis of this psoas abscess4,7 ) .
however , in recent years , tuberculosis - induced psoas infections are again emerging with the recurrence of tuberculosis in industrial countries and increase in the number of human immunodeficiency virus ( hiv ) infections5 ) .
mckley et al5 ) emphasized the role of the spine as the primary source of infection for secondary psoas abscess . according to the most case reports on psoas abscesses ,
tuberculous psoas abscess occurring secondary to direct extension from other adjacent structures or even hematogenous seeding from a distant site is less frequent8 ) .
however , there have been hardly any reports on tuberculous psoas abscess presenting as a manifestation of tuberculosis , without evidence of an active infection elsewhere8 ) . even in the case of our patient
, there was no evidence of a tubercle bacillus infection anywhere but except in the surgical portion .
a retrospective review of the first mri of our patient revealed some unusual findings of the left psoas muscle , which had been overlooked earlier .
axial mri of the l2 vertebra revealed that the left psoas muscle was irregular shaped , ill - defined , and heterogeneously enlarged compared to the right psoas muscle and both paraspinal muscles at the level of the vertebral burst fracture .
in addition , the coronal t2-weighted mri revealed a thick line of high - signal intensity along the left psoas muscle ( fig .
even though it is very difficult to determine whether asymmetric swelling of the left psoas muscle was due to trauma or infection , we consider that this unusual finding was a result of the infection .
if it was caused by the trauma , there would have been more contusions of the paraspinal muscle than that of the psoas because the psoas is positioned anterior to the paraspinal muscle .
moreover , because the abnormality was detected only in the left psoas and not in either paraspinal muscle or the right psoas , it is difficult to determine whether the condition was a result of the trauma .
we also consider that the possibility of tuberculous spondylitis extending to the vertebral body before injury is low .
we assume that vertebral fracture and subsequent spinal surgery can make the progress of the primary psoas abscess around surrounding tissues quicker . in the majority of earlier cases , the patients , as in our case ,
although fever , abdominal or back pain , and limited hip - joint mobility form the classical triad of psoas abscess , they can be inconsistently presented1 ) .
retrospective examination revealed that our patient also had abdominal pain and intermittent limited hip - joint mobility , weeks before the traffic accident .
therefore , suspicious clinical finding , radiological study , and microbial culture study of the pus , are crucial in the diagnosis of tuberculous psoas abscess .
this report might be significant , considering the possibility of missed diagnosis of psoas abscess in patients with acute lumbar compression fracture caused by trauma , even though the unusual findings of the left psoas muscle in the first mri were not histologically examined .
unfortunately , because we mainly focused on the traumatic injury , we did not conduct a medical examination through interrogation and radiology prior to surgery , and as a result , diagnosis and treatment of psoas abscess and tuberculous spondylitis were considerably delayed . therefore , despite the critical state of the patient in similar emergencies , surgeons should always pay close attention to the radiological findings and clinical symptoms of the patients , before considering a surgical intervention or biopsy .
 the authors present a rare case of tuberculous spondylitis and a large abscess in the left psoas muscle that occurred after spinal surgery for an acute traumatic burst fracture of the l2 vertebral body . 
 we retrospectively reviewed the patient 's first magnetic resonance imaging ( mri ) we found that some unusual findings , indicative of psoas abscess had been overlooked . 
 as a result , diagnosis and treatment of tuberculous psoas abscess and spondylitis were considerably delayed . despite the critical condition of patients in a similar emergency , surgeons should always pay close attention to the radiological findings and clinical symptoms of the patient before considering a surgical intervention or biopsy . 
INTRODUCTION
CASE REPORT
DISCUSSION
CONCLUSION