Therapeutic Potential of Mesenchymal Stem Cells (MSCs) and MSC-Derived Extracellular Vesicles for the Treatment of Spinal Cord Injury.

Spinal cord injury (SCI) is a life-threatening condition that leads to permanent disability with partial or complete loss of motor, sensory, and autonomic functions. SCI is usually caused by initial mechanical insult, followed by a cascade of several neuroinflammation and structural changes. For ameliorating the neuroinflammatory cascades, MSC has been regarded as a therapeutic agent. The animal SCI research has demonstrated that MSC can be a valuable therapeutic agent with several growth factors and cytokines that may induce anti-inflammatory and regenerative effects. However, the therapeutic efficacy of MSCs in animal SCI models is inconsistent, and the optimal method of MSCs remains debatable. Moreover, there are several limitations to developing these therapeutic agents for humans. Therefore, identifying novel agents for regenerative medicine is necessary. Extracellular vesicles are a novel source for regenerative medicine; they possess nucleic acids, functional proteins, and bioactive lipids and perform various functions, including damaged tissue repair, immune response regulation, and reduction of inflammation. MSC-derived exosomes have advantages over MSCs, including small dimensions, low immunogenicity, and no need for additional procedures for culture expansion or delivery. Certain studies have demonstrated that MSC-derived extracellular vesicles (EVs), including exosomes, exhibit outstanding chondroprotective and anti-inflammatory effects. Therefore, we reviewed the principles and patho-mechanisms and summarized the research outcomes of MSCs and MSC-derived EVs for SCI, reported to date.

Definitions of unfavorable surgical outcomes and their risk factors based on disability score after spine surgery for lumbar spinal stenosis.

BACKGROUND: Risk factors for unfavorable surgical outcomes are dependent on the definitions of the unfavorable surgical outcomes. The aims of this study were to compare risk factors for each unfavorable surgical outcome according to two different definitions of "unfavorable" surgical outcomes after surgery for lumbar spinal stenosis (LSS) as well as compare the clinical course from the preoperative period to 3 years postoperatively between cases with favorable and unfavorable outcomes according to the two different definitions. METHODS: Overall, 295 patients who underwent spine surgery for LSS and a follow-up evaluation at 3 years postoperatively were enrolled and divided into favorable and unfavorable groups, based on two different definitions for unfavorable surgical outcomes, as evaluated at 12 months postoperatively: the patient-reported outcome (PRO) and minimal clinically important difference (MCID) methods. In the PRO method, patients with a postoperative Oswestry Disability Index (ODI) score > 22 were considered as having an "unfavorable" outcome, whereas in the MCID method, those with a postoperative ODI score that changed < 12.8 points from the preoperative value were classified as having an "unfavorable" outcome. As a primary outcome, risk factors for unfavorable surgical outcomes according to each definition were investigated at 12 months postoperatively. RESULTS: In the PRO method, female sex (P = 0.011; odds ratio (OR): 2.340), elementary school attainment (vs. university attainment; P = 0.035; OR: 2.875), and higher preoperative ODI score (P = 0.028; OR: 2.340) were associated with higher odds for an unfavorable surgical outcome. In the MCID method, a higher preoperative ODI score was associated with higher odds (P <  0.001; OR: 0.920) of a favorable surgical outcome. In the PRO method, the favorable outcome group demonstrated significantly lower visual analog scale for back and leg pain and lower ODI scores than the unfavorable outcome group at 3 years postoperatively, whereas in the MCID method, clinical outcomes were not different between the two groups at 3 years postoperatively. CONCLUSION: A higher preoperative ODI score may be a risk factor for postoperative ODI > 22 after surgery for LSS. It may also be associated with higher odds for improvements in the ODI score of > 12.8.

Delayed presentation of infected common iliac artery pseudoaneurysm caused by malpositioned pedicle screw after minimally invasive scoliosis surgery.

PURPOSE: To report delayed onset common iliac artery perforation and infected pseudoaneurysm caused by malpositioned pedicle screw after minimally invasive scoliosis surgery (MISS). METHODS: A 21-year-old female was referred to our hospital with a 1-week history of abrupt right-sided low back pain, lower abdominal pain, and fever with a history of MISS using cannulated pedicle screws 18 months earlier. Paravertebral arterial erosion with pseudoaneurysm and retroperitoneal and paraspinal abscess were suspected. RESULTS: We performed resection of the pseudoaneurysm, vascular repair of right common iliac artery by angioplasty with a bovine patch and removal of implant. At 6 months after the last surgery, she had no limitations or problems in her daily activities with no recurrence of low back pain, abdominal pain, or fever as well as without loss of deformity. CONCLUSIONS: Our case showed that misplaced pedicle screws can cause potentially fatal complications, such as infected pseudoaneurysm, even in the late postoperative period.

Traumatic posterior dislocation of atlanto-axial joint with anterior arch fracture in the patient of atlanto-occipital assimilation: A case report.

INTRODUCTION AND IMPORTANCE: Traumatic atlanto-axial dislocation (AAD) is relatively uncommon and can pose life-threatening risks. In this case, we describe a patient with a combination of AAD, an anterior arch fracture of the atlas, and a rare congenital anomaly known as atlanto-occipital assimilation (AOA). CASE PRESENTATION: A 70-year-old man presented with posterior neck pain and right-sided torticollis following an accident that collision with a car while riding an electric scooter. Radiographic findings confirmed posterior AAD with anterior arch fracture of C1 in the inherent setting of AOA. The patient showed no neurologic deficit, so a closed reduction technique using Gardner-Wells tongs was attempted in an awakened state, and successful reduction could achieve without a neurologic deficit. After about three months of rigid brace application, head and neck motion was allowed, and no recurrence of dislocation or cervical pain occurred during the follow-up period of about one year. CLINICAL DISCUSSION: Because the posterior AAD is usually accompanied by anterior arch fracture of atlas, the transverse atlantal ligament remained intact. So nonoperative management after manual reduction was possible. The presence of a C1 anterior arch fracture observed in our case can be regarded as an indicator predicting the success of closed reduction of AAD. CONCLUSION: Our case highlighted the successful nonoperative management of traumatic posterior AAD with an accompanying anterior arch fracture of the atlas in a peculiar inherent combination of AOA through the closed reduction technique and rigid cervical brace application.

Diagnostic value of ultrasound and computed tomographic arthrography in diagnosing anterosuperior acetabular labral tears.

PURPOSE: This study investigated the sensitivity, specificity, and accuracy of ultrasound as well as the computed tomography arthrography (CTA) findings and arthroscopic findings for the diagnosis of anterosuperior acetabular tear and correlated tear types using the Lage classification system on ultrasound and CTA compared with the arthroscopic findings. METHODS: We retrospectively reviewed the results of ultrasonographic examinations conducted before injection and after injection of contrast for subsequent CTA in 36 hips (34 patients; 24 men [71%] and 10 women [29%]; mean age, 36 years). All patients had chronic groin pain and a positive impingement test. We analyzed the sensitivity, specificity, and accuracy before injection, after injection, and at CTA and compared these with findings with the arthroscopic findings. Interobserver agreement and intraobserver reproducibility of the presence of a tear and tear type in the anterosuperior quadrant of the acetabular labrum on ultrasonography and CTA were calculated by use of κ coefficients. RESULTS: The sensitivity, specificity, and accuracy for sonographic detection of labral tear before injection/after injection were 58%/79%, 67%/58%, and 61%/72%, respectively, for observer 1 and 75%/92%, 25%/42%, and 58%/75%, respectively, for observer 2. The sensitivity, specificity, and accuracy for CTA detection of labral tears were 96%, 92%, and 94%, respectively, for observer 1 and 88%, 92%, and 89%, respectively, for observer 2. When the sonographic classification was compared with the arthroscopic findings of observer 1 and observer 2, the accuracy before injection/after injection was only 53%/67% and 58%/75%, respectively. The accuracy of morphologic classification of CTA and arthroscopic findings of observer 1 and observer 2 was 83% and 75%, respectively. Interobserver correlation before injection and at CTA was poor (κ = 0.056) and moderate (κ = 0.642), respectively. CONCLUSIONS: Although intra-articular injection during sonographic examination could improve diagnosis of labral tears, sonographic examination as a diagnostic technique is still of limited use. However, CTA shows reliable validity in the diagnosis of acetabular labral tears. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Combined Anterior-Posterior Fusion Versus Posterior Alone Fusion for Cervical Myelopathy in Athetoid-Cerebral Palsy.

STUDY DESIGN: Retrospective comparative study. OBJECTIVES: Although some studies have discussed the use of lateral mass screws (LMSs) in patients with cerebral palsy (CP), it is unclear whether posterior LMS fixation alone is a suitable method. We aimed to compare the clinical, radiological, and surgical outcomes of 2 surgical modalities, namely, combined anterior-posterior (A-P) instrumented fusion and posterior fusion alone, in athetoid-type CP patients with cervical myelopathy (CM). METHODS: We analyzed 63 patients with athetoid-CP and CM who underwent posterior fusion only with LMS (group A, 35 patients) and A-P fusion (group B, 28 patients). The primary outcome was the 1- and 3-year fusion rates for the surgical segments. The secondary outcomes included the clinical outcomes based on pain intensity determined using the visual analog scale score, neck disability index, and 17-point Japanese Orthopedic Association score, radiological, and surgical outcomes. RESULTS: Fusion was achieved at 3 years postoperatively in 22 of 35 patients (63%) in group A and in 26 of 28 patients (93%) in group B (P = 0.02). The posterior neck pain intensity was also significantly lower in group B than in group A 2 and 3 years postoperatively (P = 0.02 and 0.01, respectively). The incidence of screw loosening and implant-related problems was higher in group A (60%) than in group B (21%) (P = 0.01). The other clinical and radiological parameters were similar between the groups. CONCLUSIONS: For athetoid CP-induced CM, combined A-P fusion would result in superior clinical and radiological outcomes compared to posterior fusion alone.

To cross or not to cross the cervicothoracic junction in multilevel posterior cervical fusion: a systematic review and meta-analysis.

BACKGROUND: Inclusion of the cervicothoracic junction (CTJ) during decision-making regarding the surgical level of multilevel posterior cervical fusion (PCF) surgery remains the subject of debate, largely due to a lack of studies on the topic. Thus, we considered that meta-analysis based on recent high-quality clinical studies might enable better-informed decision-making regarding the selection of the distal level of multilevel PCF, particularly concerning the advisability of crossing the CTJ. PURPOSE: To compare the outcomes of patients who underwent multilevel PCF with or without crossing the CTJ (the thoracic and cervical groups, respectively) by the distal construct. STUDY DESIGN: A systematic review and meta-analysis. METHODS: We searched the Cochrane, Embase, and Medline databases for articles that compared the intra- and post-operative outcomes of patients who underwent multilevel PCF surgery with or without extension of surgery to include the CTJ, using January 7, 2021, as the publication cutoff date. Group differences in primary and secondary outcome measures were analyzed for significance (p<.05). All reported means were pooled. RESULTS: A total of 1,904 publications were assessed, and eight studies met the study criteria. The cervical group had a significantly greater fusion rate than the thoracic group (p=.03), but higher adjacent segment disease (ASD) and reoperation rates (ASD: OR=3.15, p=.007; reoperation: OR=1.93, p=.008). As regards surgical outcomes, mean blood loss was less and operation time was shorter in the cervical group (p=.008 and .009, respectively). However, mean hospital stays were not significantly different (p=.12), and neither were the rates of complications, such as metal failure and hematoma. CONCLUSIONS: In the current study, fusion rate, blood loss, and operation time were better in the cervical group than in the thoracic group, but ASD incidence and ASD-related complication rates at the CTJ were greater in the cervical group. For patients with higher risk factors for adjacent-segment degeneration, crossing the CTJ may be warranted.

Diagnostic Technology for Spine Pathology.

Diagnostic techniques for spinal pathologies have been developed in accordance with advances in technology. Accurate diagnosis of spinal pathology is essential for appropriate management of spinal diseases. Since the development of X-rays in 1895 and computed tomography (CT) in 1967, several diagnostic imaging modalities have been utilized for detecting spinal pathologies, including radiography, CT, magnetic resonance imaging, and radionuclide imaging. In addition to diagnostic imaging technologies, electrodiagnostic tests, including electromyography and nerve conduction studies, play a significant role as diagnostic tools, as spinal diseases are mostly profoundly associated with pathologies of the neural structures, such as the spinal cord and nerve root, and extent of injury at the structure cannot be adequately detected by conventional imaging techniques. In patient-specific treatment strategies, usage of diagnostic modalities is of great importance; thus, we should be aware of the basic details and approaches of the different diagnostic modalities. In this review, the authors discuss the details of the technologies that aid in the diagnosis of spinal pathologies.

Transforaminal Lumbar Interbody Fusion (TLIF) versus Oblique Lumbar Interbody Fusion (OLIF) in Interbody Fusion Technique for Degenerative Spondylolisthesis: A Systematic Review and Meta-Analysis.

Preoperative pathology requiring fusion surgery has a great impact on postoperative outcomes. However, the previous clinical and meta-analysis studies did not control for the pathology. In this systematic review, the authors aimed to compare oblique lumbar interbody fusion (OLIF) with transforaminal interbody fusion (TLIF) as an interbody fusion technique in lumbar fusion surgery for patients with degenerative spondylolisthesis (DS). We systematically searched for relevant articles in the available databases. Among the 3022 articles, three studies were identified and met the inclusion criteria. In terms of radiological outcome, the amount of disc height restoration was greater in the OLIF group than in the TLIF group, but there was no significant difference between the two surgical techniques (p = 0.18). In the clinical outcomes, the pain improvement was not significantly different between the two surgical techniques. In terms of surgical outcomes, OLIF resulted in a shorter length of hospital stay and less blood loss than TLIF (p < 0.0001 and p = 0.02, respectively). The present meta-analysis indicated no significant difference in clinical, radiological outcomes, and surgical time between TLIF and OLIF for DS, but the lengths of hospital stay and blood loss were better in OLIF than TLIF. Though encouraging, these findings were based on low-quality evidence from a small number of retrospective studies that are prone to bias.

The C2 Cortical Screw, an Alternative Fixation Technique for the C2 Segment During High Cervical Spine Surgery: Technical Note.

BACKGROUND: For posterior fixation of C2 vertebra (the axis), several fixation techniques such as pedicle screw, laminar screw, and pars screw have been reported. A pedicle screw (PS) is considered the strongest among the techniques, but certain situations make PS fixation impossible or difficult. These include patients with a narrow C2 pedicle or high-riding vertebral artery. We introduced an alternative screw technique for C2 that addressed the aforementioned problems with safely placing it, which we termed a cortical screw (CS) for C2. METHODS: Among a total of 28 cases using C2 CS for high cervical spine surgery, 2 cases using C2 CS were described. One patient was a 76-year old woman with a gait disturbance and myelopathic symptoms and diagnosed with C1-C2 myelopathy and translational instability. The other case was 54-year old man with posterior neck pain after traffic accident and diagnosed with C1-C2 fracture-dislocation. We used the C2 CS as an alternative technique for high cervical spine surgery in these patients and describe the ideal entry point and trajectory. RESULTS: A postoperative computed tomography scan confirmed proper positioning of the C1 posterior arch screw and C2 CS, with satisfactory reduction of the C2 dens and adequate restoration of the C1-C2 spinal canal. The patient experienced no screw-related postoperative complications, and postoperative 1-year computed tomography images showed that solid union and good alignment of C1-2 segment was achieved. CONCLUSIONS: C2 CS can be suitable alternative for C2 screw fixation technique in posterior high cervical spine fusion surgery.

Diagnostic Modality in Spine Disease: A Review.

Spine diseases are common and exhibit several causes, including degeneration, trauma, congenital issues, and other specific factors. Most people experience a variety of symptoms of spine diseases during their lifetime that are occasionally managed with conservative or surgical treatments. Accurate diagnosis of the spine pathology is essential for the appropriate management of spine disease, and various imaging modalities can be used for the diagnosis, including radiography, computed tomography (CT), magnetic resonance imaging (MRI), and other studies such as EOS, bone scan, single photon emission CT/CT, and electrophysiologic test. Patient (or case)-specific selection of the diagnostic modality is crucial; thus, we should be aware of basic information and approaches of the diagnostic modalities. In this review, we discuss in detail, about diagnostic modalities (radiography, CT, MRI, electrophysiologic study, and others) that are widely used for spine disease.

Long-term Outcome of Selective Thoracic Fusion Using Rod Derotation and Direct Vertebral Rotation in the Treatment of Thoracic Adolescent Idiopathic Scoliosis: More Than 10-Year Follow-up Data.

STUDY DESIGN: This was a retrospective comparative study. OBJECTIVE: To evaluate long-term outcomes of selective thoracic fusion (STF) using both rod derotation (RD) and direct vertebral rotation (DVR) with pedicle screw instrumentation (PSI) in the treatment of thoracic adolescent idiopathic scoliosis (AIS) with a minimum 10-year follow-up. SUMMARY OF BACKGROUND DATA: Postoperative compensation and maintenance of the unfused lumbar curve after STF is very important factor for the satisfactory results in the treatment of thoracic AIS. PATIENTS AND METHODS: Sixty-five patients with thoracic AIS treated with STF from the neutral vertebra (NV) to NV or NV-1 with RD and DVR were retrospectively analyzed with a minimum 10-year follow-up. Patients were divided into 2 groups: satisfactory (n=52) and unsatisfactory groups (n=13). Unsatisfactory results were defined as an adding-on, a lowest instrumented vertebra (LIV) tilt of >10 degrees, or coronal balance >15 mm. RESULTS: No significant differences were observed in the main thoracic curve between the satisfactory and unsatisfactory groups postoperatively (P=0.218) and at the last follow-up (P=0.636). Significant improvements of LIV tilt and disk angle were observed in both groups, but these improvements deteriorated during the follow-up period in the unsatisfactory group. Significant differences of apical vertebra (AV) and end vertebra (EV) were observed postoperatively (AV: P=0.001, EV: P=0.001) and at the last follow-up (AV: P<0.000, EV: P<0.000) between the 2 groups. CONCLUSIONS: STF using RD and DVR can achieve satisfactory deformity correction for thoracic AIS with satisfactory compensatory lumbar curve that was maintained over long-term follow-up. Progression of unfused lumbar curve closely related with LIV tilt and disk angle showing insufficient DVR. Therefore, STF with sufficient DVR required to achieve satisfactory deformity correction and prevent a distal adding-on phenomenon in the treatment of thoracic AIS.

Comparison of Union Rates Between Autogenous Iliac Crest Bone Graft and Local Bone Graft as Fusion Materials in Lumbar Fusion Surgery: An Evaluation of Up to 3-Level Fusion.

OBJECTIVE: To compare the radiologic union rates between autogenous iliac crest bone graft (ICBG) and local bone graft in 1- to 3-level lumbar fusion. METHODS: We reviewed 178 consecutive patients who underwent 1- to 3-level lumbar fusion surgery because of lumbar spinal stenosis. Fusion status of the anterior or posterior column was evaluated by plain radiographs obtained at 24 months postoperatively. If at least either the anterior or posterior column was fused, that segment was regarded as having achieved fusion and was termed segment union. The definition of overall union was achieving union of all segments in a single patient. RESULTS: For each ICBG group and local bone graft group, fusion rate of the anterior and posterior column, and rate of the segments and overall union at postoperative 2 years were not different between the groups, regardless of surgery level. In the overall union rate according to the fusion level, the ICBG group showed constant overall fusion rate according to the fusion level (i.e., 96.9%, 96.9%, and 93.1% for 1-, 2-, and 3-level fusion), but tended to decrease with increasing level in the local bone graft group (100%, 95.8%, and 85.7% for 1-, 2-, and 3-level fusion, respectively) without statistically significant differences. CONCLUSIONS: The union rate of 3-level fusion was not inferior to those of 1- or 2-level fusion in both ICBG and local bone graft patients. Local bone graft could be regarded as an adequate option for not only 1- or 2-level lumbar fusion but also 3-level lumbar fusion surgery.

Selective blocking laminoplasty in cervical laminectomy and fusion to prevent postoperative C5 palsy.

BACKGROUND CONTEXT: Cervical laminectomy and fusion (CLF) is a common surgical option for multilevel cord compression. Postoperative C5 palsy occurrence after CLF has been a vexing problem for spine physicians. The posterior shift of the cord following laminectomy has been implicated as a major factor for postoperative C5 palsy, but attempts by spine surgeons to mitigate excessive shift while providing sufficient decompression have not been well reported. PURPOSE: To compare the incidence of postoperative C5 palsy after performing selective blocking laminoplasty concurrently with CLF to those of conventional CLF. STUDY DESIGN: A retrospective comparative study of prospectively collected data. PATIENT SAMPLE: Of 116 cervical myelopathy patients with degenerative cervical myelopathy, ossification of the posterior longitudinal ligament, and multilevel disc herniation, 93 patients (69 in group A [CLF group] and 24 in group B [selective blocking laminoplasty with CLF, CLF-S group]) were included in the study. OUTCOME MEASURES: The primary outcome measure was the occurrence of postoperative C5 palsy. Secondary end points included (1) clinical outcomes based on pain intensity, neck disability index (NDI), Japanese Orthopaedic Association (JOA) score, (2) radiologic outcomes including cervical alignment and fusion rate at 1 year and hardware complications, and (3) perioperative data (hospital stay, blood loss, and operative times). METHODS: We compared the occurrence of postoperative C5 palsy, as well as clinical, radiologic, and surgical outcomes, between the two groups at 1-year follow-up. RESULTS: The patients in both groups were statistically similar between the groups with respect to demographic characteristics such as age, sex, smoking status, body mass index, preoperative pathology, surgical segments, and the degree of the cervical lordosis. Postoperative C5 palsy developed in 9 of 61 patients (14%) in group A and in 0 of 24 patients (0%) in group B (CLF-S group) (p=.03). Postoperative neck pain, NDI, and JOA improvement were not significantly different between the two groups (p=.93, 0.90, and 0.79, respectively). Perioperative data did not differ significantly between the two groups. CONCLUSIONS: This study showed that performing selective blocking laminoplasty might lead to reducing the incidence of postoperative C5 palsy in CLF surgery.

Traumatic posterior atlantooccipital dislocation combined with type II dens fracture and C1 anterior arch fracture: Two case reports.

RATIONALE: Traumatic AOD is rare but highly associated with upper cervical spine injuries. We found no references in the literature of traumatic posterior atlantooccipital dislocation (AOD) combined with type II dens fracture (Anderson-D'Alonzo classification) and C1 anterior arch fracture. PATIENT CONCERNS: The first case was a 93-year-old male patient who was admitted to the Emergency Department complaining of incomplete quadriplegia after a fall from a height. The second was a 53-year-old male patient who visited the emergency department complaining of posterior neck pain following a high-speed motor vehicle collision. DIAGNOSIS: Reconstructed computed tomography (CT) scans clearly demonstrated posterior AOD combined with type II dens fracture and C1 anterior arch fracture. In addition, magnetic resonance imaging (MRI) also revealed type II transverse atlantal ligament injury (Dickman's classification) in the first patient. INTERVENTIONS: The patients chose not to undergo surgery; instead, they were immobilized with a rigid cervical brace. OUTCOMES: The patients were lost to follow-up. LESSONS: A thorough clinical evaluation and radiologic investigation (CT and MRI) on concomitant upper cervical injuries should be evaluated in traumatic AOD patients.

Walking more than 90minutes/week was associated with a lower risk of self-reported low back pain in persons over 50years of age: a cross-sectional study using the Korean National Health and Nutrition Examination Surveys.

BACKGROUND CONTEXT: Physical activity, such as muscle strengthening and aerobic exercise, has been found to be effective for low back pain (LBP). However, the association between weekly walking duration and LBP in the general population remains poorly understood. OBJECT: This study aimed (1) to analyze the association between walking and LBP and (2) to examine this association according to walking duration and overall walking days per week in a general population over 50years of age using a representative sample of Korean adults. STUDY DESIGN: Cross-sectional study. PATIENT SAMPLE: Data from the Korea National Health and Nutrition Examination Surveys V and VI, performed from 2010 to 2015. OUTCOME MEASURES: Multiple logistic regression analysis was performed to determine the association between walking days and duration and LBP. Analysis was restricted to participants aged over 50years who responded to surveys on LBP and walking activity. METHODS: National health and nutrition examination surveys were performed in the Korean general population (N=48,482) from 2010 to 2015. LBP status was surveyed using a self-reported questionnaire form ("Have you complained of LBP for more than 30days during the past 3 months?"). Daily walking activity (low-intensity activity) was evaluated using the following two questions: (1) "During the last 7days, on how many days did you walk for at least 10 minutes at a time? This includes at work and at home, walking to travel from place to place, and any other walking that you have done solely for recreation, sport, exercise, or leisure." (2) "How much time did you usually spend walking on each of those days?" Walking duration per day was classified into two categories: over 30min/day and over 1h/day. Overall walking days per week were categorized into <3, 3-4, and ≥5days/week. Basic characteristics, comorbidities, socioeconomic status, and other variables were used to create multiple logistic regression models. No sources of funding and no conflicts of interest were associated with this study. RESULTS: Walking for more than 3days per week for over 30 minutes at a time was negatively associated with LBP in the unadjusted (adjusted odds ratio [aOR]: 0.65, p<.001) and fully adjusted logistic regression models (aOR: 0.79, p<.001). Similarly, walking for more than 5days per week for over 1 hour at a time was negatively associated with LBP in the unadjusted (aOR: 0.62, p<.001) and fully adjusted logistic regression models (aOR: 0.76, p<.001). The risk of LBP decreased with increasing walking days and duration. CONCLUSIONS: Our study showed that longer walking duration was associated with a lower risk of LBP using a cross-sectional health survey in the Korean general population. Regular walking with a longer duration for more than 3days/week is significantly associated with a lower risk of LBP in the general population aged over 50years.

Is the Use of a Unilateral Biportal Endoscopic Approach Associated with Rapid Recovery After Lumbar Decompressive Laminectomy? A Preliminary Analysis of a Prospective Randomized Controlled Trial.

OBJECTIVE: The purpose of this study was to assess the immediate postoperative clinical outcomes and perform a preliminary analysis of the effectiveness of biportal endoscopic approaches to lumbar decompressive laminectomy in the treatment of lumbar spinal stenosis. METHODS: All participants (64 patients) were randomly assigned in a 1:1 ratio to either the biportal endoscopic lumbar decompressive laminectomy (BE-D) group or the mini-open microscopic lumbar decompressive laminectomy (MI-D) group. Early postoperative outcomes were evaluated using clinical and surgical technique-related outcomes. The visual analog scale (VAS) pain score was measured at 6 time points after surgery (at 4, 8, 16, 24, and 48 hours and 2 weeks). Surgical technique-related outcomes were also analyzed. RESULTS: There were no significant differences in the preoperative demographics between the 2 groups. The VAS pain score from 8 to 48 hours (P < 0.05) was significantly lower in the BE-D group than in the MI-D group. Moreover, the total amount of fentanyl usage was higher in the MI-D group than in the BE-D group after surgery (P = 0.026). The length of hospital stay was lower in the BE-D group than in the MI-D group (P = 0.048). The operative time and creatinine phosphokinase level were not significantly different between the groups (P >0.05). Postoperative drainage was significantly higher in the BE-D group than in the MI-D group. CONCLUSIONS: BE-D was associated with rapid pain recovery, low fentanyl usage, and early discharge after surgery, but its other benefits have not yet been shown.

Learning Curve for Lumbar Decompressive Laminectomy in Biportal Endoscopic Spinal Surgery Using the Cumulative Summation Test for Learning Curve.

OBJECTIVE: The purpose of the present study was to determine the learning curve for biportal endoscopic spinal surgery (BESS) for decompressive laminectomy in lumbar spinal stenosis using a learning curve cumulative summation test (LC-CUSUM). METHODS: The surgeon was proficient in open and microscopic decompressive laminectomy in lumbar spinal stenosis but did not have any experience with BESS or other endoscopic surgery techniques. The learning curve of BESS was investigated using LC-CUSUM analysis. Procedure success was defined as an operative time <75 minutes, the mean operative time with microscopic decompression laminectomy. RESULTS: The present study included the first 60 patients who had undergone single-level decompressive laminectomy using BESS by a single orthopedic surgeon. The mean operative time for decompressive laminectomy by BESS was 83.8 ± 37.9 minutes. The mean operative time in the early learning period (≤30 cases) and late learning period (second 30 cases) was 105.3 ± 39.7 minutes and 62.4 ± 19.9 minutes, respectively. The overall complication rate was ∼10%. The LC-CUSUM signaled competency for surgery at the 58th operation, indicating that sufficient evidence had accumulated to prove that the surgeon was competent. Thus, a trainee with no experience with BESS had reached adequate performance at 58 cases. CONCLUSIONS: The results of the present study have demonstrated that a substantial learning period could be needed before adequate performance can be achieved with lumbar decompressive laminectomy using BESS.

How to Avoid Distal Adding-on Phenomenon for Rigid Curves in Major Thoracolumbar and Lumbar Adolescent Idiopathic Scoliosis? Identifying the Incidence of Distal Adding-on by Selection of Lowest Instrumented Vertebra.

OBJECTIVE: We sought to compare the radiologic outcomes for different distal fusion levels in a rigid curve with major thoracolumbar and lumbar (TL/L) adolescent idiopathic scoliosis (AIS) using rod derotation (RD) with direct vertebral rotation (DVR) after pedicle screw instrumentation (PSI). METHODS: This study finally enrolled 28 patients who were diagnosed with AIS in rigid curve with major TL/L curves, treated by PSI with RD and DVR and with a minimum 2-year follow-up. Patients were divided into 2 groups, L3 and L4, on the basis of the distal fusion level at the lowest instrumented vertebra (LIV) of L3 or L4. RESULTS: There was no significant difference in TL/L curve, thoracic (minor), and compensatory (caudal) curves between the L3 and L4 groups either postoperatively (P = 0.162, 0.426, and 0.762, respectively) or at the last follow-up (P = 0.952, 0.620, and 0.562, respectively). The overall prevalence of unsatisfactory results was 42.9% (12/28 patients). The prevalence of unsatisfactory results was 61.1% (11/18) in the L3 group and 10% (1/10) in the L4 group, which was significantly different (P < 0.05). CONCLUSIONS: Unsatisfactory results occurred more often in the L3 group than in the L4 group, and unsatisfactory results had significant influence on progression of TL/L and distal compensatory curves. Such progression was closely correlated with deteriorating LIV disk angle in the L3 group. Therefore if the curve is rigid, LIV should be extended to L4 to avoid the adding-on phenomenon in the treatment of major TL/L AIS using RD with DVR after PSI.

Effect of Direct Vertebral Rotation in Single Thoracic Adolescent Idiopathic Scoliosis: Better 3-Dimensional Deformity Correction.

OBJECTIVE: To analyze the effects of direct vertebral rotation (DVR) on radiologic outcomes in the treatment of thoracic adolescent idiopathic scoliosis after selective thoracic fusion with pedicle screw instrumentation. METHODS: Adolescent idiopathic scoliosis patients with single thoracic curves (n = 110) treated by selective thoracic fusion with a minimum of 2 years of follow-up were retrospectively analyzed. The patients were separated into 2 groups: non-DVR (n = 63) and DVR (n = 47). RESULTS: There was a significant difference in fused segments between the non-DVR and DVR groups (P < 0.001). There was also a significant difference in main thoracic curve postoperatively (P = 0.001) and at the last follow-up (P = 0.006) between the non-DVR and DVR groups. However, there was no significant difference in proximal thoracic and lumbar curves postoperatively (proximal thoracic curve: P = 0.186; lumbar curve: P = 0.155) and at the last follow-up (proximal thoracic curve: P = 0.250; lumbar curve: P = 0.060) between the 2 groups. Significant improvements in the lowest instrumented vertebra tilt and disc angle were noted but then slight deteriorations in such were observed during the follow-up period in the non-DVR group. The prevalence of unsatisfactory results was 20.6% (13 of 63) in the non-DVR group and 19.1% (9 of 47) in the DVR group, with no significant difference (P = 0.522). CONCLUSIONS: For correcting single thoracic adolescent idiopathic scoliosis by selective thoracic fusion with pedicle screw instrumentation, the addition of DVR to the surgical procedure showed comparable radiologic outcomes compared with non-DVR procedures.