Surgical Extent of Metastatic Spine Tumor Excision and Its Effects on Postoperative Ambulatory Function: Comparison of Extensive Wide versus Palliative Excision Surgery / 대한척추외과학회지

STUDY DESIGN: Retrospective study. OBJECTIVES: To compare surgical outcomes such as the ambulatory period and survival according to different surgical excision tactics for metastatic spine tumors (MSTs). SUMMARY OF LITERATURE REVIEW: Surgical outcomes, such as pain relief and survival, in patients with MSTs have been reported in several studies, but the effects of differences in surgical extent on the ambulatory period have rarely been reported. MATERIALS AND METHODS: Ninety-six patients with MSTs who underwent palliative (n=60) or extensive wide excision (n=36) were included. Palliative excision was defined as partial removal of the tumor as an intralesional piecemeal procedure for decompression. Extensive wide excision was defined as a surgical attempt to remove the whole tumor at the index level as completely as possible. The primary outcome was the ambulatory period following surgery. Other demographic and radiographic parameters were analyzed to identify the risk factors for loss of ambulatory ability and survival. Perioperative complications were also assessed. RESULTS: The mean postoperative ambulatory period was longer in the extensive wide excision group (average 14.8 months) than in the palliative excision group (average 11.7 months) (p=0.021). The survival rates were not significantly different between the two surgical excision groups (p=0.680). However, postoperative ambulatory status and major complications within 30 days postoperatively were significant prognostic factors for survival (p=0.003 and p=0.032, respectively). CONCLUSIONS: The extent of surgical excision affected the ambulatory period, and the complication rates were similar, regardless of surgical excision tactics. A proper surgical strategy to achieve postoperative ambulatory ability and to reduce perioperative complications would have a favorable effect on survival.

Clinical Significance of Preoperative Embolization for Non-Hypervascular Metastatic Spine Tumors

OBJECTIVE: The efficacy of preoperative embolization for hypervascular metastatic spine disease (MSD) such as renal cell and thyroid cancers has been reported. However, the debate on the efficacy of preoperative embolization for non-hypervascular MSD still remains unsettled. The purpose of this study is to determine whether preoperative embolization for non-hypervascular MSD decreases perioperative blood loss. METHODS: A total of 79 patients (36 cases of preoperative embolization and 43 cases of non-embolization) who underwent surgery for metastatic spine lesions were included. Representative hypervascular tumors such as renal cell and thyroid cancers were excluded. Intraoperative and perioperative estimated blood losses (EBL), total number of transfusion and calibrated EBL were recorded in the embolization and non-embolization groups. The differences in EBL were also compared along with the type of surgery. In addition, the incidence of Adamkiewicz artery and complications of embolization were assessed. RESULTS: The average age of 50 males and 29 females was 57.6±13.5 years. Lung (30), hepatocellular (14), gastrointestinal (nine) and others (26) were the primary cancers. The demographic data was not significantly different between the embolization and the non-embolization groups. There were no significant differences in intraoperative EBL, perioperative EBL, total transfusion and calibrated EBL between two groups. However, intraoperative EBL and total transfusion in patients with preoperative embolization were significantly lower than in non-embolization in the corpectomy group (1645.5 vs. 892.6 mL, p=0.017 for intraoperative EBL and 6.1 vs. 3.9, p=0.018 for number of transfusion). In addition, the presence of Adamkiewicz artery at the index level was noted in two patients. Disruption of this major feeder artery resulted in significant changes in intraoperative neuromonitoring. CONCLUSION: Preoperative embolization for non-hypervascular MSD did not reduce perioperative blood loss. However, the embolization significantly reduced intraoperative bleeding and total transfusion in corpectomy group. Moreover, the procedure provided insights into the anatomy of tumor and spinal cord vasculature.

Clinical Significance of Preoperative Embolization for Non-Hypervascular Metastatic Spine Tumors

OBJECTIVE: The efficacy of preoperative embolization for hypervascular metastatic spine disease (MSD) such as renal cell and thyroid cancers has been reported. However, the debate on the efficacy of preoperative embolization for non-hypervascular MSD still remains unsettled. The purpose of this study is to determine whether preoperative embolization for non-hypervascular MSD decreases perioperative blood loss.METHODS: A total of 79 patients (36 cases of preoperative embolization and 43 cases of non-embolization) who underwent surgery for metastatic spine lesions were included. Representative hypervascular tumors such as renal cell and thyroid cancers were excluded. Intraoperative and perioperative estimated blood losses (EBL), total number of transfusion and calibrated EBL were recorded in the embolization and non-embolization groups. The differences in EBL were also compared along with the type of surgery. In addition, the incidence of Adamkiewicz artery and complications of embolization were assessed.RESULTS: The average age of 50 males and 29 females was 57.6±13.5 years. Lung (30), hepatocellular (14), gastrointestinal (nine) and others (26) were the primary cancers. The demographic data was not significantly different between the embolization and the non-embolization groups. There were no significant differences in intraoperative EBL, perioperative EBL, total transfusion and calibrated EBL between two groups. However, intraoperative EBL and total transfusion in patients with preoperative embolization were significantly lower than in non-embolization in the corpectomy group (1645.5 vs. 892.6 mL, p=0.017 for intraoperative EBL and 6.1 vs. 3.9, p=0.018 for number of transfusion). In addition, the presence of Adamkiewicz artery at the index level was noted in two patients. Disruption of this major feeder artery resulted in significant changes in intraoperative neuromonitoring.CONCLUSION: Preoperative embolization for non-hypervascular MSD did not reduce perioperative blood loss. However, the embolization significantly reduced intraoperative bleeding and total transfusion in corpectomy group. Moreover, the procedure provided insights into the anatomy of tumor and spinal cord vasculature.

Benign Gastric Ulcer with Epstein-Barr Virus Infection Mimicking Malignant Gastric Ulcer / 대한소화기학회지

Epstein-Barr virus (EBV) is the cause of infectious mononucleosis, which is characterized by fever, lymphadenopathy, and sore throat. On the other hand, gastrointestinal symptoms of EBV infection like dyspepsia, abdominal pain are non-specific and rarely encountered, which means it is difficult to diagnose gastric involvement of EBV infection without suspicion. The relation between gastric carcinoma and gastric lymphoma associated with EBV infection is well defined, but relations with other EBV-associated gastrointestinal diseases such as gastritis and peptic ulcer disease have rarely been reported. We report a case of benign gastric ulcer with EBV infection confirmed by endoscopic and histological findings.

Surgical Extent of Metastatic Spine Tumor Excision and Its Effects on Postoperative Ambulatory Function: Comparison of Extensive Wide versus Palliative Excision Surgery

OBJECTIVES@#To compare surgical outcomes such as the ambulatory period and survival according to different surgical excision tactics for metastatic spine tumors (MSTs).SUMMARY OF LITERATURE REVIEW: Surgical outcomes, such as pain relief and survival, in patients with MSTs have been reported in several studies, but the effects of differences in surgical extent on the ambulatory period have rarely been reported.@*MATERIALS AND METHODS@#Ninety-six patients with MSTs who underwent palliative (n=60) or extensive wide excision (n=36) were included. Palliative excision was defined as partial removal of the tumor as an intralesional piecemeal procedure for decompression. Extensive wide excision was defined as a surgical attempt to remove the whole tumor at the index level as completely as possible. The primary outcome was the ambulatory period following surgery. Other demographic and radiographic parameters were analyzed to identify the risk factors for loss of ambulatory ability and survival. Perioperative complications were also assessed.@*RESULTS@#The mean postoperative ambulatory period was longer in the extensive wide excision group (average 14.8 months) than in the palliative excision group (average 11.7 months) (p=0.021). The survival rates were not significantly different between the two surgical excision groups (p=0.680). However, postoperative ambulatory status and major complications within 30 days postoperatively were significant prognostic factors for survival (p=0.003 and p=0.032, respectively).@*CONCLUSIONS@#The extent of surgical excision affected the ambulatory period, and the complication rates were similar, regardless of surgical excision tactics. A proper surgical strategy to achieve postoperative ambulatory ability and to reduce perioperative complications would have a favorable effect on survival.

Seroepidemiology of Hepatitis Viruses and Hepatitis B Genotypes of Female Marriage Immigrants in Korea

PURPOSE: The Korean society has moved rapidly toward becoming a multicultural society. This study aimed to estimate the seroprevalence of hepatitis viruses and investigate hepatitis B virus (HBV) genotypic diversity in female marriage immigrants. MATERIALS AND METHODS: Screening program was conducted at support centers for multicultural families in 21 administrative districts in Korea between July 2011 and January 2017. A total of 963 female marriage immigrants were included in this study. Blood samples were tested for hepatitis viral markers and HBV genotype. RESULTS: Subjects' median age was 33 years (20–40 years), and they originated from nine countries including Vietnam (n=422, 43.8%), China (n=311, 32.3%), the Philippines (n=85, 8.8%), Cambodia (n=58, 6.0%), and Japan (n=39, 4.0%). About 30% (n=288) of subjects required hepatitis A vaccination. HBsAg positive rate was 5.4% (n=52). Positive HBsAg results were the highest in subjects from Southeast Asia (6.6%, n=38). Anti-HBs positive rate was 60.4% (n=582). About 34% (n=329) of subjects who were negative for anti-HBs and HBsAg required HBV vaccinations. Genotypes B and C were found in 54.6% (n=12) and 45.4% (n=10) of the 22 subjects with HBV, in whom genotypes were tested. Eight (0.8%) subjects were positive for anti-HCV. Positive anti-HCV results were the highest in subjects from Central Asia (7.9%, n=3). CONCLUSION: Testing for hepatitis viral marker (hepatitis A virus IgG and HBsAg/anti-HBs) is needed for female marriage immigrants. Especially, HBV genotype B is different from genotype C of Koreans. Therefore, interest and attention to vaccination programs for female marriage immigrants are necessary for both clinicians and public health institutes.

Clinical implication of serum uric acid level in pegylated interferon and ribavirin combination therapy for chronic hepatitis C infection

BACKGROUND/AIMS: Combined treatment of pegylated interferon-α (PEG-IFN) and ribavirin (RBV) has long been accepted as the standard treatment for chronic hepatitis C virus (HCV) infection. Many predictive factors for treatment response have been identified. The aim of this study was to evaluate the efficacy and safety of combined PEG-IFN plus RBV and to examine the value of serum uric acid as a predictive factor in the treatment of chronic hepatitis C. METHODS: A total of 74 patients chronically infected with HCV were enrolled between December 2004 and June 2009. Patients received subcutaneous PEG-IFN (α-2a: 180 μg once a week) in combination with RBV (1,000 to 1,200 mg daily depending on body weight). We evaluated treatment responses represented by early virologic response (EVR), end-of-treatment response (ETR), sustained virologic response (SVR), and relapse, as well as diverse adverse events. Various viral and host features were also assessed to clarify factors associated with treatment response. RESULTS: During treatment, EVR was achieved in 26 patients (26/33, 78.8%) with HCV genotype 1. ETR and SVR were achieved in 59 (77.6%) and 56 patients (73.6%), respectively, across all genotypes. Genotype 2/3, lower HCV RNA, and lower uric acid were associated with higher SVR. CONCLUSIONS: The treatment response to combination therapy with PEG-IFN plus RBV was effective, especially in genotype 2/3. Uric acid might be useful as a predictive factor for response to therapy for chronic hepatitis.

Prevalence of Neuropathic Pain and Patient-Reported Outcomes in Korean Adults with Chronic Low Back Pain Resulting from Neuropathic Low Back Pain

STUDY DESIGN: A noninterventional, multicenter, cross-sectional study. PURPOSE: We investigated the prevalence of neuropathic pain (NP) and patient-reported outcomes (PROs) of the quality of life (QoL) and functional disability in Korean adults with chronic low back pain (CLBP). OVERVIEW OF LITERATURE: Among patients with CLBP, 20%–55% had NP. METHODS: Patients older than 20 years with CLBP lasting for longer than three months, with a visual analog scale (VAS) pain score higher than four, and with pain medications being used for at least four weeks before enrollment were recruited from 27 general hospitals between December 2014 and May 2015. Medical chart reviews were performed to collect demographic/clinical features and diagnosis of NP (douleur neuropathique 4, DN4). The QoL (EuroQoL 5-dimension, EQ-5D; EQ-VAS) and functional disability (Quebec Back Pain Disability Scale, QBPDS) were determined through patient surveys. Multiple linear regression analyses were performed to compare PROs between the NP (DN4≥4) and non-NP (DN4 < 4) groups. RESULTS: A total of 1,200 patients (females: 65.7%; mean age: 63.4±13.0 years) were enrolled. The mean scores of EQ-5D, EQ-VAS, and QBPDS were 0.5±0.3, 55.7±19.4, and 40.4±21.1, respectively. Among all patients, 492 (41.0%; 95% confidence interval, 38.2%–43.8%) suffered from NP. The prevalence of NP was higher in male patients (46.8%; p < 0.01), in patients who had pain based on radiological and neurological findings (59.0%; p < 0.01), and in patients who had severe pain (49.0%; p < 0.01). There were significant mean differences in EQ-5D (NP group vs. non-NP group: 0.4±0.3 vs. 0.5±0.3; p < 0.01) and QBPDS (NP group vs. non-NP group: 45.8±21.2 vs. 36.3±20.2; p < 0.01) scores. In the multiple linear regression, patients with NP showed lower EQ-5D (β=−0.1; p < 0.01) and higher QBPDS (β=7.0; p < 0.01) scores than those without NP. CONCLUSIONS: NP was highly prevalent in Korean patients with CLBP. Patients with CLBP having NP had a lower QoL and more severe dysfunction than those without NP. To enhance the QoL and functional status of patients with CLBP, this study highlights the importance of appropriately diagnosing and treating NP.

Immunoproteasome induction is suppressed in hepatitis C virus-infected cells in a protein kinase R-dependent manner

By changing the relative abundance of generated antigenic peptides through alterations in the proteolytic activity, interferon (IFN)-γ-induced immunoproteasomes influence the outcome of CD8⁺ cytotoxic T lymphocyte responses. In the present study, we investigated the effects of hepatitis C virus (HCV) infection on IFN-γ-induced immunoproteasome expression using a HCV infection cell culture system. We found that, although IFN-γ induced the transcriptional expression of mRNAs encoding the β1i/LMP2, β2i/MECL-1 and β5i/LMP7 immunoproteasome subunits, the formation of immunoproteasomes was significantly suppressed in HCV-infected cells. This finding indicated that immunoproteasome induction was impaired at the translational or posttranslational level by HCV infection. Gene silencing studies showed that the suppression of immunoproteasome induction is essentially dependent on protein kinase R (PKR). Indeed, the generation of a strictly immunoproteasome-dependent cytotoxic T lymphocyte epitope was impaired in in vitro processing experiments using isolated 20S proteasomes from HCV-infected cells and was restored by the silencing of PKR expression. In conclusion, our data point to a novel mechanism of immune regulation by HCV that affects the antigen-processing machinery through the PKR-mediated suppression of immunoproteasome induction in infected cells.

Immunogenicity of MenACWY-CRM in Korean Military Recruits: Influence of Tetanus-Diphtheria Toxoid Vaccination on the Vaccine Response to MenACWY-CRM

The quadrivalent meningococcal conjugate vaccine (MenACWY-CRM) has been introduced for military recruits in Korea since 2012. This study was performed to evaluate the immunogenicity of MenACWY-CRM in Korean military recruits. In addition, the influence of tetanus-diphtheria toxoids (Td) vaccination on the vaccine response to MenACWY-CRM was analyzed. A total of 75 military recruits were enrolled. Among them, 18 received a dose of MenACWY-CRM only (group 1), and 57 received Td three days before MenACWY-CRM immunization (group 2). The immunogenicity of MenACWY-CRM was compared between the two groups. The serum bactericidal activity with baby rabbit complement was measured before and three weeks after immunization against serogroups A, C, W-135, and Y. The geometric mean titers (GMTs) against four serogroups were significantly increased in both groups after immunization. Compared to group 2, group 1 exhibited significantly higher vaccine responses in several aspects: post-immune GMTs against serogroup A and C, seroresponse rates against serogroup A, and a fold increases of titers against serogroup A, C, and Y. MenACWY-CRM was immunogenic against all vaccine-serogroups in Korean military recruits. Vaccine response to MenACWY-CRM was influenced by Td administered three days earlier.

Immunogenicity of MenACWY-CRM in Korean Military Recruits: Influence of Tetanus-Diphtheria Toxoid Vaccination on the Vaccine Response to MenACWY-CRM

The quadrivalent meningococcal conjugate vaccine (MenACWY-CRM) has been introduced for military recruits in Korea since 2012. This study was performed to evaluate the immunogenicity of MenACWY-CRM in Korean military recruits. In addition, the influence of tetanus-diphtheria toxoids (Td) vaccination on the vaccine response to MenACWY-CRM was analyzed. A total of 75 military recruits were enrolled. Among them, 18 received a dose of MenACWY-CRM only (group 1), and 57 received Td three days before MenACWY-CRM immunization (group 2). The immunogenicity of MenACWY-CRM was compared between the two groups. The serum bactericidal activity with baby rabbit complement was measured before and three weeks after immunization against serogroups A, C, W-135, and Y. The geometric mean titers (GMTs) against four serogroups were significantly increased in both groups after immunization. Compared to group 2, group 1 exhibited significantly higher vaccine responses in several aspects: post-immune GMTs against serogroup A and C, seroresponse rates against serogroup A, and a fold increases of titers against serogroup A, C, and Y. MenACWY-CRM was immunogenic against all vaccine-serogroups in Korean military recruits. Vaccine response to MenACWY-CRM was influenced by Td administered three days earlier.

Immune-mediated Liver Injury in Hepatitis B Virus Infection

Hepatitis B virus (HBV) is responsible for approximately 350 million chronic infections worldwide and is a leading cause of broad-spectrum liver diseases such as hepatitis, cirrhosis and liver cancer. Although it has been well established that adaptive immunity plays a critical role in viral clearance, the pathogenetic mechanisms that cause liver damage during acute and chronic HBV infection remain largely known. This review describes our current knowledge of the immune-mediated pathogenesis of HBV infection and the role of immune cells in the liver injury during hepatitis B.

A Case of Acute Myocarditis as the Initial Presentation of Crohn's Disease

We experienced a case of acute myocarditis as the initial presentation of Crohn's disease. A 19-year-old woman was admitted with impaired consciousness, shock, and respiratory failure. She had suffered from frequent diarrhea and abdominal pain for several years. Cardiac troponin I and creatine kinase-MB fraction levels were elevated to 5.32 and 16.66 ng/mL, respectively. A 12-lead electrocardiogram showed sinus tachycardia, and a chest radiograph revealed interstitial pulmonary edema. An echocardiogram showed dilated ventricles with akinesia of the basal to apical inferoseptal, anteroseptal, anterior, and inferior left ventricular walls and severely impaired systolic function. Intensive care with inotropic support was effective, and her clinical condition gradually improved. Two weeks later, a colonoscopy revealed ulceration with stenosis in the terminal ileum and multiple aphthous ulcers in the rectum. A biopsy of the rectum revealed non-caseating granulomatous inflammation. She was diagnosed with Crohn's disease presenting with acute myocarditis.

Kimura's Disease of the Trunk / 대한정형외과학회잡지

Kimura's disease is a very rare, benign, lymphoproliferative inflammatory disorder of unknown etiology. A 48 year-old man had multiple soft tissue masses in his trunk, which was diagnosed as Kimura's disease by histopathologic evaluation. Here, we report the case with a review of the literature.

A Case of Undifferentiated Carcinoma with Osteoclast-Like Giant Cells in the Pancreas / 대한내과학회지

Undifferentiated carcinomas with osteoclast-like giant cells are rare pancreatic and periampullary neoplasms that mimic giant cell tumors of bone morphologically. Recently, we experienced an osteoclast-like giant cell tumor arising in the tail of the pancreas. A 76-year-old male was admitted with epigastric discomfort and indigestion. Abdominal computed tomography (CT) and abdominal magnetic resonance imaging (MRI) showed a 3x3-cm mass containing necrotic and hemorrhagic areas in the tail of the pancreas. A distal pancreatectomy and splenectomy were performed. Histological examination showed tumor cell components consisting of mononuclear pleomorphic cells admixed with osteoclastic giant cells. The final diagnosis was undifferentiated carcinoma with osteoclast-like giant cells with ductal adenocarcinoma in the pancreas.

Duodenal Carcinoid Tumor Treated by Endoscopic Mucosal Resection / 대한소화기내시경학회지

Duodenal carcinoid tumors are rare, and they represent only 2.0~8.9% of all gastrointestinal carcinoid tumors in the western countries. Duodenal carcinoid tumors have previously been treated by surgical resection. The recently recommended treatment for a carcinoid tumor smaller than 1 cm in diameter is endoscopic resection. We experienced a case of a duodenal carcinoid tumor in a 56 year-old man who presented with upper abdominal pain. On the endoscopic examination, a 6 mm sized polypoid lesion with a central depression was noticed on the duodenal bulb. The biopsy confirmed the diagnosis of carcinoid tumor. The endoscopic ultrasound probe showed a hypoechoic tumor that was confined to the submocosal layer. The tumor was completely resected by an endoscopic mucosal resection technique and using a transparent cap.

Thoracic Disc Herniation of the Adjacent Segment With Acutely Progressing Myelopathy

We report a case of a 66-year-old woman with progressing myelopathy. Her history revealed instrumented fusion from T10 to S1 for degenerative lumbar kyphosis and spinal stenosis. The plain radiographs showed narrowing of the intervertebral disc space with a gas shadow and sclerotic end-plate changes at T9-T10. Magnetic resonance imaging revealed a posterolateral mass compressing the spinal cord at the T9-T10 level. The patient was treated with a discectomy through the posterior approach combined with posterior instrumentation. The patient's symptoms and myelopathy resolved completely after the discectomy and instrumented fusion. The thoracic disc herniation might have been caused by the increased motion and stress concentration at the adjacent segment.

Revision Surgery after Vertebroplasty or Kyphoplasty

BACKGROUND: We wanted to investigate the leading cause of failed vertebroplasty or kyphoplasty. METHODS: Twelve patients (10 females and 2 males) who underwent revision surgery after vertebroplasty or kyphoplasty were included. In 4 cases, vertebroplasty was done for two or more levels. Six cases with kyphoplasty were included. Through the retrospective review of the radiographic studies and medical record, we analyzed the etiology of the revision surgery. RESULTS: Uncontrolled back pain was the main clinical presentation. In 4 cases, neurological symptoms were noted, including one case with conus medullaris syndrome. The average time to the revision surgery after vertebroplasty or kyphoplasty was 15 months. Infection (4 cases) and progressive kyphosis with collapse (8 cases) were the causes for the revision. A solid pattern of inserted bone cement and bone resorption around the cement were noted in the all cases with progressive collapse and kyphosis. CONCLUSIONS: Infection, misdiagnosis and progressive kyphosis were causes of the revision surgery after vertebroplasty and kyphoplasty. A solid pattern of accumulation of bone cement and peri-cement bone resorption might be related with the progressive collapse.

Glucocorticoid Mechanism of Inhibition of the Inflammatory Cells in Lumbar Intervertebral Disc Cells Stimulated by TNF-alpha Production of Nuclear Factor-kappaB / 대한정형외과연구학회지

PURPOSE: To analyze the action mechanism of NF-kappaB, IkappaB-alpha and effect of the Dexamethasone (DEXA) in mediating this inflammation, after stimulating cultured herniated intervertebral disc cells with TNF-alpha. MATERIALS AND METHODS: After cultured human intervertebral disc cells passaged three times, they were divided into four groups: A control group (A), DEXA treatment group (B), TNF-alpha treated group (C), TNF-alpha and DEXA were treated at the same time (D). IL-6 and IL-1beta gene expression were measured with semi-quantitative RT-PCR. Western blot analysis was performed to measure protein expression of IkappaB-alpha in the above groups for 10 minutes, 1 hour, 2 hours. In addition, in order to explain the mechanism of NF-kappaB nuclear binding for each group, the nuclear amount of NF-kappaB binding in the nucleus is measured by EMSA. RESULTS: In RT-PCR, expression of IL-6 and IL-1beta was greatest in group C, followed by group D, group A. IkappaB-alpha expression of the group treated with DEXA was not detected in Western blot results within 10 minutes. However, if stimulated by TNF-alpha, the DEXA was not inhibited of IkappaB-alpha concentration. After 1 hour and 2 hours, IkappaB-alpha levels were expressed by cells autonomously (autoregulatory induction). EMSA results expression levels in nuclear protein was maintained in accordance with protein expression. CONCLUSIONS: Our study shows that DEXA inhibits the production of mediators such as inflammatory IL-6 and IL-1beta, however, may not inhibit the transcription of NF-kappaB stimulated by TNF-alpha.

The Clinical Effect of Gait Load Test in Two Level Lumbar Spinal Stenosis

STUDY DESIGN: This study is a prospective, clinical study assessing the efficacy of selective decompression of the level responsible in a two-level stenosis in accordance with the neurological findings defined by the gait load test with a treadmill. PURPOSE: To clarify the clinical features of multilevel lumbar spinal stenosis (LSS) regarding the neurological level responsible for the symptoms, neurogenic claudication, and outcomes of selective decompression. OVERVIEW OF LITERATURE: Most spine surgeons have reported that multilevel compression of the cauda equina induces a more severe impairment of the nerve function than a single-level compression. However, the clinical effects of multilevel LSS on the cauda equine and nerve roots are unknown. METHODS: A total of 21 patients with lumbar spinal canal stenosis due to spondylosis and degenerative spondylolisthesis were selected. The level responsible for the symptoms in the two-level stenosis was determined from the neurological findings on the gait load test and functional diagnosis based on a selective nerve root block. All patients underwent a prospective, selective decompression at the level neurologically responsible only. The average follow-up period was 2.6 years (range, 1 to 6 years). The postsurgical outcome was defined using the Visual Analogue Scale (VAS) at the post-gait load test, 2 weeks after surgery, 3 months after surgery and at the last follow up. RESULTS: Before surgery, the mean threshold distance and mean walking tolerance was 34.3 m and 113 m, respectively. All patients had neurogenic claudication and 19 of the patients had cauda equina syndrome, including hypesthesia in 11 cases, muscle weakness in 5 cases and radicular pain in 7 cases. Selective nerve blocks to determine the level responsible for the lumbosacral symptoms in 2 cases revealed a mean VAS score of 7.1, 2.61, 3.04, and 3.47 at the post-gait load test, 2 weeks after surgery, 3 months after surgery and at the last follow up, respectively. All subjects underwent surgery. After the operation, neurogenic claudication with or without cauda equna syndrome subsided in all patients. CONCLUSIONS: The gait load test allows an objective and quantitative evaluation of the gait characteristics of patients with lumbar canal stenosis and is useful for determining the appropriate level for surgical treatment.