A Beginner’s Perspective on Biportal Endoscopic Spine Surgery in Single-Level Lumbar Decompression: A Comparative Study with a Microscopic Surgery

Background@#The application of biportal endoscopic spinal surgery (BESS) in spine surgery is increasing. However, the clinical results of related studies have been inconsistent. In this study, the perioperative and clinical outcomes of two techniques in singlelevel lumbar decompression surgery were compared using the perspective of a spine surgeon experienced in microscopic surgery but inexperienced in BESS. @*Methods@#This is a retrospective study performed with prospectively collected data. From April 2019, 50 consecutive patients who underwent a single-level lumbar decompression surgery with BESS were evaluated. Additionally, the data of 150 consecutive patients who underwent the same microscopic surgery before April 2019 were collected. We performed 1 : 1 ratio propensity score matching for these two groups to adjust for baseline variables. The postoperative patient-reported outcome measures included the Oswestry Disability Index (ODI) and numeric rating scale for the back and leg preoperatively and at 6 months after surgery. The laboratory data (C-reactive protein [CRP, mg/L] and hemoglobin [Hb, g/dL]) were measured preoperatively and 3 times (1, 2, and 3 or 4 days) postoperatively. In these periods, the peak and lowest CRP and Hb concentrations were evaluated. The perioperative outcomes, operation time (from skin incision to dressing), length of hospital stay, drainage (for 24 hours after surgery), and surgeryrelated complications were also evaluated. @*Results@#Forty-seven patients (27 men and 20 women) were included in each group. The postoperative 6-month ODI was significantly lower in the BESS group than in the microscope group (6.90 ± 5.98 vs. 11.54 ± 9.70). The peak CRP concentration (16.63 ± 19.41 vs. 42.40 ± 37.73, p < 0.001) and CRP increment (peak CRP minus preoperative CRP, 14.69 ± 19.47 vs. 40.71 ± 37.32, p < 0.001) were significantly higher in the microscope group. Operation time (83.72 ± 35.71 vs. 70.27 ± 23.24, p = 0.047) was significantly longer in the BESS group. Surgery-related complications were found in 6 and 3 cases in the BESS group (3 revisions, 2 dural tears, and 1 conversion to open surgery) and microscope group (2 revisions and 1 hematoma), respectively. @*Conclusions@#BESS as a new technique resulted in satisfying short-term outcomes. It was a well-tolerated option for surgical treatment of single-level lumbar degenerative disease. The relatively high incidence of recurrence at the index level and incidental dural tears should be considered for surgeons new to BESS; however, these were manageable complications.

Feasibility of Non-window Three-Dimensional– Printed Porous Titanium Cage in Posterior Lumbar Interbody Fusion: A Pilot Trial

Background@#The commercially available design of a three-dimensional (3D)–printed titanium (3D-Ti) cage can be divided into two types according to the presence of a window: a cage with a window that allows filling of bone graft materials and a non-window cage for stand-alone use. This prospective observational case series study aimed to explore the clinical feasibility of using a nonwindow type 3D-Ti cage in cases of combined window and non-window cage implantation. Furthermore, we evaluated the bone in growth patterns of non-window cages and their correlation with published fusion grading systems. @*Methods@#A total of 31 consecutive patients who underwent single-level posterior lumbar interbody fusion surgery were included. Two 3D-Ti cages with different designs were inserted: a non-window cage on the left side and a window cage on the right side.Radiographic fusion was defined by the segmental angle between flexion and extension radiographs (F-E angle) and cage bridging bone (CBB) scores on computed tomography. The association between the F-E angle and osteointegration scoring system including the surface osteointegration ratio (SOR) score was analyzed. @*Results@#Radiographic fusion was achieved in 27 of 31 patients (87%) at 12 months postoperatively. Among the non-window cages, 23 of 31 (74.2%) had fair SOR scores, while 19 of 31 (61.3%) window cages had fair intra-cage CBB scores. The higher the SOR score was, the smaller the flexion-extension angle (SOR 0 vs. SOR 1: 6.30° ± 2.43° vs. 1.95° ± 0.99°, p < 0.001; SOR 0 vs. SOR 2: 6.03° ± 2.43° vs. 0.99°± 0.74°, p < 0.001). @*Conclusions@#The clinical feasibility of using a non-window 3D-Ti cage during lumbar interbody fusion might be acceptable. Furthermore, a newly suggested fusion criterion for the use of the non-window cage, the SOR score, showed a significant association with the published fusion grading systems, demonstrating its feasibility in determining interbody fusion in lumbar spinal surgery.

Postoperative Segmental Motion up to 1 Year Following Single-Level Anterior Cervical Discectomy and Fusion: Plate versus Non-plate

Methods@#In retrospectively collected data, 149 patients who underwent single-level ACDF for degenerative disease were enrolled and divided into non-plating (n=66) and plating (n=83). Interspinous motion (ISM) at the arthrodesis segment, Numeric Rating Scale (NRS) for neck pain, and Neck Disability Index (NDI) were serially evaluated at 3, 6, and 12 months postoperatively. Predictable factors for fusion, including age, sex, plating, diabetes, smoking, and type of grafts, were investigated, and fusion was defined as ISM <1 mm. @*Results@#In both groups, ISM was the highest at 3 months and gradually decreased thereafter, and the plating group showed significantly lower serial ISM than the non-plating group at 12 months. The plating group had lower NRS and NDI scores than the nonplating group at 12 months, and the difference in the NRS scores was statistically significant, particularly at 3 and 6 months, although that of the NDI scores was not. In a multivariate analysis, plating was the most powerful predictor for fusion. @*Conclusions@#Plating significantly decreases the serial ISM compared with non-plating in single-level ACDF, and such decreased motion is correlated with decreased neck pain until 12 months postoperatively, particularly at 3 and 6 months. Given that plating was the most predictive factor for fusion, we recommend plating even in single-level ACDF for better early clinical outcomes.

An Updated Overview of Low Back Pain Management

We aimed to determine the recommendation level for the treatment of acute and chronic low back pain (LBP). A systematic review (SR) of the literature was performed and all English-language articles that discuss acute and chronic LBP, including MEDLINE and the Cochrane Database of Systematic Reviews, were searched. Of the 873 searched literature reports, 259 articles, including 131 clinical trials, 115 SRs, nine meta-analyses, and four clinical guidelines were analyzed. In these articles, high-quality randomized controlled trials, SRs, and used well-written clinical guidelines were reviewed. The results indicated multiple acute and chronic LBP treatment methods in the literature, and these reports when reviewed included general behavior, pharmacological therapy, psychological therapy, specific exercise, active rehabilitation and educational interventions, manual therapy, physical modalities, and invasive procedures. The Trial conclusions and SRs were classified into four categories of A, B, C, and D. If there were not enough high-quality articles, it was designated as “I” (insufficient). This review and summary of guidelines may be beneficial for physicians to better understand and make recommendations in primary care.

Proximal Junctional Kyphosis in Adult Spinal Deformity: Definition, Classification, Risk Factors, and Prevention Strategies

Proximal junctional problems are among the potential complications of surgery for adult spinal deformity (ASD) and are associated with higher morbidity and increased rates of revision surgery. The diverse manifestations of proximal junctional problems range from proximal junctional kyphosis (PJK) to proximal junctional failure (PJF). Although there is no universally accepted definition for PJK, the most common is a proximal junctional angle greater than 10° that is at least 10° greater than the preoperative measurement. PJF represents a progression from PJK and is characterized by pain, gait disturbances, and neurological deficits. The risk factors for PJK can be classified according to patient-related, radiological, and surgical factors. Based on an understanding of the modifiable factors that contribute to reducing the risk of PJK, prevention strategies are critical for patients with ASD.

MR Imaging Characteristics of Primary T-Cell Lymphoma of the Cauda Equina: A Case Report and Literature Review

Primary central nervous system lymphoma is a rare form of extranodal non-Hodgkin lymphoma, and primary T-cell lymphoma of the cauda equina is extremely rare. We describe a case involving a 56-year-old female who presented with low back pain and radiating leg pain for 4 months. MRI of the lumbar spine revealed an elongated, multinodular intradural lesion of approximately 10 cm from the L4 body to the S2 body level with iso-signal intensity on T1-weighted imaging, heterogeneous iso- and high-signal intensity on T2-weighted imaging, and a heterogeneous intense enhancement on gadolinium contrast-enhanced T1-weighted imaging. A peripheral T-cell lymphoma of the cauda equina was diagnosed on the basis of immunohistochemical and T-cell receptor gamma gene rearrangement analysis after intradural biopsy of the mass.

Adult Spinal Deformity: Current Concepts and Decision-Making Strategies for Management

Adult spinal deformity (ASD) is characterized by three-dimensional abnormalities of the thoracic or thoracolumbar spine that exerts significant impacts on the health-related quality of life (HRQoL). With the important effects that deformity of the sagittal plane exerts on the HRQoL, there have been paradigm shifts in ASD evaluation and management. Loss of lumbar lordosis is recognized as a key driver of ASD followed by reducing kyphosis, pelvic retroversion, and knee flexion. The Scoliosis Research Society (SRS)– Schwab classification reflects the sagittal spinopelvic parameters that correlate pain and disability in ASD patients. Although the SRS–Schwab classification provides a realignment target framework for surgeons, a structured patient-specific systemic approach is crucial for the process of decision-making. ASD management should be focused on restoring age-specific harmonious alignment and should consider the comorbidities and risk factors of each patient to prevent catastrophic complications and enhance the HRQoL.

Impact of Bone Mineral Density on the Incidence of Age-Related Vertebral Fragility Fracture

Background@#Vertebral fragility fracture (VFF) is a common fracture related to osteoporosis. However, VFF might be asymptomatic and often occurs in patients without osteoporosis. Therefore, we investigated the characteristics of age-related VFF and their correlation with bone mineral density (BMD). Furthermore, we analyzed other factors affecting VFF @*Methods@#Medical records from a single center were retrospectively reviewed for 2,216 patients over 50 years old with vertebral fractures conservatively treated from 2005 to 2016. Patients' age, gender, body mass index (BMI), BMD, fracture level, previous vertebral fractures, and anti-osteoporosis medications were obtained. Patients were divided into fragilityon-fragility groups and age sub-groups. The odds ratio for VFF in relation to BMD was evaluated. We also identified other predictive factors for VFF by age groups. @*Results@#The fragility group had a higher women ratio, older age, lower BMI, lower BMD, and greater incidence of previous vertebral fractures than the non-fragility group. VFFs were seen in 41.18% of normal BMD patients aged 50–59 and 67.82% of those aged 60–69. The proportion of VFFs increased with age in all WHO osteoporosis classifications. Patients with osteopenia and osteoporosis were 1.57 and 2.62 fold more likely to develop VFFs than normal BMD. In the younger group (under 70), age, women, BMD, and previous vertebral fracture were significant factors affecting VFF, and in the older group (70 and over), age, women, and BMD were factors. In the fragility group, anti-osteoporosis medication rates were 25.08% before and 45.96% after fracture. @*Conclusion@#Considerable VFFs occurred in the younger age groups without osteoporosis and age itself was another important predictor of VFF especially in older age groups. The discrepancy between the incidence of VFF and BMD suggests the necessity of supplemental screening factors and anti-osteoporosis treatment guidelines using only BMD should be reconsidered.

Adult Spinal Deformity: Current Concepts and Decision-Making Strategies for Management

Adult spinal deformity (ASD) is characterized by three-dimensional abnormalities of the thoracic or thoracolumbar spine that exerts significant impacts on the health-related quality of life (HRQoL). With the important effects that deformity of the sagittal plane exerts on the HRQoL, there have been paradigm shifts in ASD evaluation and management. Loss of lumbar lordosis is recognized as a key driver of ASD followed by reducing kyphosis, pelvic retroversion, and knee flexion. The Scoliosis Research Society (SRS)– Schwab classification reflects the sagittal spinopelvic parameters that correlate pain and disability in ASD patients. Although the SRS–Schwab classification provides a realignment target framework for surgeons, a structured patient-specific systemic approach is crucial for the process of decision-making. ASD management should be focused on restoring age-specific harmonious alignment and should consider the comorbidities and risk factors of each patient to prevent catastrophic complications and enhance the HRQoL.

Considerations for Fluoroscopic Guided Intervention in Lumbar Spine / 대한정형외과학회잡지

Spinal block procedures are useful methods that reduce the need for surgical treatment. In addition to their therapeutic aspects of pain relief, in many patients, they are also used for diagnostic purposes to distinguish from symptoms originating from extra-spinal areas. Therefore, these procedures are the most basic technique for orthopedic surgeons dealing with diseases from limbs and spine. On the other hand, despite the simplicity of the instruments and drugs used, the overall understanding of them and the lack of knowledge of the possible side effects and complications can cause serious harm to the patient at the beginning of the trial. Therefore, it is necessary to understand the types of drugs used in the spinal block procedures, pharmacokinetic properties, and the side effects of each drug. In addition, efforts should be made to identify their indications, as well as advantages and disadvantages of each procedure to avoid possible complications. The purpose of this review was to provide basic knowledge and skills necessary for lumbar spinal block procedures as well as provide the reader with the ability to perform themselves.

Locating the Instant Center of Rotation in the Subaxial Cervical Spine with Biplanar Fluoroscopy during In Vivo Dynamic Flexion-Extension

BACKGROUND: Recently, biplanar fluoroscopy is used to evaluate the cervical kinematics, especially to locate the instant center of rotation (ICR) during in vivo motion. This study aims to ascertain the ICR at each cervical segment in the sagittal plane during dynamic motion and assess the differences from previous studies. METHODS: While three healthy subjects were performing full flexion-extension, two oblique views aligned horizontally and angled at approximately 55° were obtained by biplanar fluoroscopy. The minimum degree to detect significant movement in a helical axis model was set at 2°, and anterior-posterior and superior-inferior locations of each ICR were defined. To evaluate the possible distribution area and overlapping area of the ICR with disc space, we drew a circle by using the calculated distance between each coordination and the mean coordination of ICR as the radius. RESULTS: During flexion-extension motion, the mean superior-inferior location of the ICR became progressively more superior, except the C5–6 segment (p = 0.015), and the mean anterior-posterior location of the ICR became progressively more anterior without exception from C2–3 to C6–7 segments, but anterior-posterior ICR locations were not significantly different among segments. The overlapping area with the distribution circle of ICR was mainly located in the posterior half in the C3–4 segment, but the overlapping area was about 80% of the total disc space in C4–5 and C6–7 segments. The overlapping was more noticeable in the lower cervical segments after exclusion of the outlier data of the C5–6 segment in subject 1. CONCLUSIONS: The ICR in the cervical spine showed a trend of moving progressively more superiorly and anteriorly and the disc space overlapping the distribution circle of ICR increased along the lower motion segments except the C5–6 segment. These findings could provide a good basis for level-specific cervical arthroplasty designs.

Neuropathic Pain after Spinal Surgery

Neuropathic pain after spinal surgery, the so-called failed back surgery syndrome (FBSS), is a frequently observed troublesome disease entity. Although medications may be effective to some degree, many patients continue experiencing intolerable pain and functional disability. Only gabapentin has been proven effective in patients with FBSS. No relevant studies regarding manipulation or physiotherapy for FBSS have been published. Spinal cord stimulation (SCS) has been widely investigated as a treatment option for chronic neuropathic pain, including FBSS. SCS was generally accepted to improve chronic back and leg pain, physical function, and sleep quality. Although the cost effectiveness of SCS has been proved in many studies, its routine application is limited considering that it is invasive and is associated with safety issues. Percutaneous epidural adhesiolysis has also shown good clinical outcomes; however, its effects persisted for only a short period. Because none of the current methods provide absolute superiority in terms of clinical outcomes, a multidisciplinary approach is required to manage this complex disease. Further studies concerning the etiology, diagnosis, treatment, and cost effectiveness of FBSS are warranted to deepen our understanding of this condition.

An Updated Overview of Low Back Pain Management in Primary Care

Currently, guidelines for lower back pain (LBP) treatment are needed. We reviewed the current guidelines and high-quality articles to confirm the LBP guidelines for the Korean Society of Spine Surgery. We searched available databases for high-quality articles in English on LBP published from 2000 to the present year. Literature searches using these guidelines included studies from MEDLINE, the Cochrane Database of Systematic Reviews, the Cochrane Central Register of Controlled Trials, and Embase. We analyzed a total of 132 randomized clinical trials, 116 systematic reviews, 9 meta-analyses, and 4 clinical guideline reviews. We adopted the SIGN checklist for the assessment of article quality. Data were subsequently abstracted by a reviewer and verified. Many treatment options exist for LBP, with a variety of recommendation grades. We assessed the recommendation grade for general behavior, pharmacological therapy, psychological therapy, and specific exercises. This information should be helpful to physicians in the treatment of LBP patients.

Neuropathic Pain Related with Spinal Disorders: A Systematic Review

Systematic literature review. To review the evidence from high-quality studies regarding the treatment of neuropathic pain originating specifically from spinal disorders. In general, treatment guidelines for neuropathic pain cover all its various causes, including medical disease, peripheral neuropathy, and cancer. However, the natural history of neuropathic pain originating from spinal disorders may differ from that of the pain originating from other causes or lesions. An expert research librarian used terms related to neuropathic pain and spinal disorders, disc herniation, stenosis, and spinal cord injury to search in MEDLINE, Embase, and Cochrane CENTRAL for primary research from January 2000 to October 2015. Among 2,313 potential studies of interest, 25 randomized controlled trials (RCTs) and 21 systematic reviews (SRs) were included in the analysis. The selection was decided based on the agreement of two orthopedic surgeons. There was a lack of evidence about medication for radiculopathy arising from disc herniation and stenosis, but intervention procedures, including epidural block, showed positive efficacy in radiculopathy and also limited efficacy in spinal stenosis. There was some evidence based on the short-term follow-up regarding surgery being superior to conservative treatments for radiculopathy and stenosis. There was limited evidence regarding the efficacy of pharmacological and electric or magnetic stimulation therapies for neuropathic pain after spinal cord injury. This review of RCTs and SRs with high-quality evidence found some evidence regarding the efficacy of various treatment modalities for neuropathic pain related specifically to spinal disorders. However, there is a need for much more supportive evidence.

Prognostic Factors for Postsurgical Recovery of Deltoid Palsy due to Cervical Disc Herniations

STUDY DESIGN: Retrospective multicenter study. PURPOSE: We aimed to investigate prognostic factors affecting postsurgical recovery of deltoid palsy due to cervical disc herniation (CDH). OVERVIEW OF LITERATURE: Little information is available about prognostic factors affecting postsurgical recovery of deltoid palsy due to CDH. METHODS: Sixty-one patients with CDH causing deltoid palsy (less than grade 3) were included in this study: 35 soft discs and 26 hard discs. Average duration of preoperative deltoid palsy was 11.9 weeks. Thirty-two patients underwent single-level surgery, 22 two-level, four three-level, and three four-level. Patients with accompanying myelopathy, shoulder diseases, or peripheral neuropathy were excluded from the study. RESULTS: Deltoid palsy (2.4 grades vs. 4.5 grades, p<0.001) and radiculopathy (6.4 points vs. 2.1 points, p<0.001) significantly improved after surgery. Thirty-six of 61 patients (59%) achieved full recovery (grade 5) of deltoid palsy, with an average time of 8.4 weeks. Longer duration of preoperative deltoid palsy and more severe radiculopathy negatively affected the degree of improvement in deltoid palsy. Age, gender, number of surgery level, and disc type did not affect the degree of improvement of deltoid palsy. Contrary to our expectations, severity of preoperative deltoid palsy did not affect the degree of improvement. Due to the shorter duration of preoperative deltoid palsy, in the context of rapid referral, early surgical decompression resulted in significant recovery of more severe grades (grade 0 or 1) of deltoid palsy compared to grade 2 or 3 deltoid palsy. CONCLUSIONS: Early surgical decompression significantly improved deltoid palsy caused by CDH, irrespective of age, gender, number of surgery level, and disc type. However, longer duration of deltoid palsy and more severe intensity of preoperative radiating pain were associated with less improvement of deltoid palsy postoperatively.

Unique Imaging Features of Spinal Neurenteric Cyst

A 50-year-old male presented with acutely progressed paraplegia. His magnetic resonance imaging demonstrated two well-demarcated components with opposite signals in one cystic lesion between the T1- and T2-weighted images at the T1 spine level. The patient showed immediately improved neurological symptoms after surgical intervention and the histopathological exam was compatible with a neurenteric cyst. On operation, two different viscous drainages from the cyst were confirmed. A unique similarity of image findings was found from a review of the pertinent literature. The common findings of spinal neurenteric cyst include an isointense or mildly hyperintense signal relative to cerebrospinal fluid for both T1- and T2-weighted images. However, albeit rarer, the signals of some part of the cyst could change into brightly hyperintensity on T1-weighted images and hypointensity on T2-weighted images due to the differing sedimentation of the more viscous contents in the cyst.

Antibiotic-impregnated Cement Plate for the Treatment of Infected Periprosthetic Femoral Fracture after Cementless Total Hip Arthroplasty: A Case Report / 대한고관절학회지

A 62-year-old man with an infected periprosthetic femoral fracture, which occurred after a cementless total hip arthroplasty (THA) procedure, was treated utilizing an antibiotic-impregnated cement plate for internal fixation. Open reduction and internal fixation using a cable plate were initially attempted in his case, but a deep infection with methicillin-resistant staphylococcus epidermidis at the fracture site occurred 2 months after the initial cable plate procedure. Using an antibiotic-impregnated cement plate for internal fixation, one month later, the fracture had stabilized. Successful fusion occurred at 12 months after deploying the antibiotic-impregnated cement plate. This technique was useful in this complicated case because it facilitated the goals of eradicating infection, alleviating pain, and improving function.

Bilateral Femoral Subtrochanteric Insufficiency Fractures after Long-term Bisphosphonate Therapy / 대한정형외과학회잡지

Bisphosphonates are widely used for the treatment of osteoporosis to prevent fractures. Although their safety and efficacy have been well documented, some recent reports have drawn attention to a possible correlation between long term bisphosphonate therapy and the occurrence of insufficiency fractures owing to prolonged bone turnover suppression. A 71-year-old woman presented to our emergency room with pain and deformity of the left thigh with low energy injury. Radiographs showed a left femur subtrochanteric fracture and a transverse sclerotic fracture line in the right femur subtrochanteric area with cortical thickening, which indicate insufficiency fractures. She had been treated with sodium alendronate 70 mg per week for 6 years and was suffering from prodromal symptoms in both thighs from 3 months ago. After surgery and intraoperative bone biopsy for a left subtrochanteric fracture, her osteoporosis medication was changed with a bone forming agent. We have analyzed the characteristics of insufficiency fractures related to long term bisphosphonate therapy. Physicians should keep in mind the possibility of insufficiency fracture in cases such as ours, especially with prodromal thigh pain.

Comparative Evaluation of Percutaneous Endoscopic Discectomy and Microdiscectomy Using Tubular Retractor System at L4-5 Level / 대한척추외과학회지

STUDY DESIGN: A prospective, non-randomized study OBJECTIVES: To evaluate the early clinical results of percutaneous endoscopic lumbar discectomy (PELD) and microdiscectomy (MD) using a tubular retractor. SUMMARY OF THE LITERATURE REVIEW: There are few reports comparing the clinical results of different minimal invasive surgical procedures for disc herniation. MATERIALS AND METHODS: Out of 41 patients who underwent a discectomy at the L4-5 level, 16 patients (Group I) underwent PELD and 25 patients (Group II) underwent MD. The surgical techniques were based on the patient's selection. The characteristics of the operation(operation time, time for C-arm, amount of removed disc) were compared with the clinical outcomes by evaluating the SLR (straight leg raising test), leg VAS (visual analogue scale), ODI (Oswestry Disability Index), hospital day, changes in disc height. RESULTS: Group I showed a larger amount of disc removed and exposure time for the C-arm than group II (p<0.05). However, the hospital day was shorter in group I than in group II (p<0.05). There were no differences in the leg VAS, ODI, the change in disc height and surgery time between the two groups at the last follow up. One case in group I had a neuropraxia of the L5 root that had recovered fully at postoperative 3months. In group II, there was one case of a postoperative hematoma and 2 cases of a dural tear. CONCLUSION: Although the early clinical outcomes were similar in both groups, group I showed a larger amount of disc removed and more exposure time to radiation but a shorter hospital stay.

Usefullness of Routine MR-Myelography at MRI for Multiple Lumbar Stenosis / 대한정형외과학회잡지

PURPOSE: To determine if MR myelography (MRM) improves the interpretation of the severity of stenosis in patients with a multi-level lumbar stenosis. MATERIALS AND METHODS: Among the patients referred for MRI with MRM prospectively, 100 patients over 50 years old with multiple lumbar stenosis were enrolled in this study. The most severe stenotic level and the degree of stenosis at that level according to the extent of the remaining subarachnoidal space (1: normal to 50%, 2: over 50% but not a total block, 3: total block) were evaluated in a blinded manner by two observers. Conventional MRI (class A), MRM (class B) and MRI+MRM (class C) was evaluated independently and the interobserver and intraobserver reliability were assessed. RESULTS: In the selection of the most severe level and degree of stenosis, both observers showed a higher level of consensus with classes B and C than classes A and C. The interobserver k average values for the selection of the most severe level in classes A, B and C were 0.649, 0.782 and 0.832, respectively. In terms of the degree of stenosis, the average in classes A, B and C were 0.727, 0.771 and 0.784, respectively. The intraobserver k values for the above two items were the highest in class (B), followed by (C) and (A) in all observers and within the range of "almost perfect" (0.81< or =k< or =1) except for the selection of the level of one observer in clause A. CONCLUSION: MRM when used in routine practice can help improve the observer reliability in assessing the severity of stenosis in multiple lumbar stenosis.