Loss of Ataxin-1 Potentiates Alzheimer's Pathogenesis by Elevating Cerebral BACE1 Transcription.

Expansion of CAG trinucleotide repeats in ATXN1 causes spinocerebellar ataxia type 1 (SCA1), a neurodegenerative disease that impairs coordination and cognition. While ATXN1 is associated with increased Alzheimer's disease (AD) risk, CAG repeat number in AD patients is not changed. Here, we investigated the consequences of ataxin-1 loss of function and discovered that knockout of Atxn1 reduced CIC-ETV4/5-mediated inhibition of Bace1 transcription, leading to increased BACE1 levels and enhanced amyloidogenic cleavage of APP, selectively in AD-vulnerable brain regions. Elevated BACE1 expression exacerbated Aß deposition and gliosis in AD mouse models and impaired hippocampal neurogenesis and olfactory axonal targeting. In SCA1 mice, polyglutamine-expanded mutant ataxin-1 led to the increase of BACE1 post-transcriptionally, both in cerebrum and cerebellum, and caused axonal-targeting deficit and neurodegeneration in the hippocampal CA2 region. These findings suggest that loss of ataxin-1 elevates BACE1 expression and Aß pathology, rendering it a potential contributor to AD risk and pathogenesis.

BGN Mutations in X-Linked Spondyloepimetaphyseal Dysplasia.

Spondyloepimetaphyseal dysplasias (SEMDs) comprise a heterogeneous group of autosomal-dominant and autosomal-recessive disorders. An apparent X-linked recessive (XLR) form of SEMD in a single Italian family was previously reported. We have been able to restudy this family together with a second family from Korea by segregating a severe SEMD in an X-linked pattern. Exome sequencing showed missense mutations in BGN c.439A>G (p.Lys147Glu) in the Korean family and c.776G>T (p.Gly259Val) in the Italian family; the c.439A>G (p.Lys147Glu) mutation was also identified in a further simplex SEMD case from India. Biglycan is an extracellular matrix proteoglycan that can bind transforming growth factor beta (TGF-ß) and thus regulate its free concentration. In 3-dimensional simulation, both altered residues localized to the concave arc of leucine-rich repeat domains of biglycan that interact with TGF-ß. The observation of recurrent BGN mutations in XLR SEMD individuals from different ethnic backgrounds allows us to define "XLR SEMD, BGN type" as a nosologic entity.

Biomass-derived carbon composites for enrichment of dilute methane from underground coal mines.

Ventilation air methane (VAM), which is the main source of greenhouse gas emissions from coal mines, has been a great challenge to deal with due to its huge flow rates and dilute methane levels (typically 0.3-1.0 vol%) with almost 100% humidity. As part of our continuous endeavor to further improve the methane adsorption capacity of carbon composites, this paper presents new carbon composites derived from macadamia nut shells (MNSs) and incorporated with carbon nanotubes (CNTs). These new carbon composites were fabricated in a honeycomb monolithic structure to tolerate dusty environment and to minimize pressure drop. This paper demonstrates the importance of biomass particle size distributions when formed in a composite and methane adsorption capacities at low pressures relevant to VAM levels. The selectivity of methane over nitrogen was about 10.4 at each relevant partial pressure, which was much greater than that (6.5) obtained conventionally (at very low pressures), suggesting that capturing methane in the presence of pre-adsorbed nitrogen would be a practical option. The equilibrium and dynamic performance of biomass-derived carbon composites were enhanced by 30 and 84%, respectively, compared to those of our previous carbon fiber composites. In addition, the presence of moisture in ventilation air resulted in a negligible effect on the dynamic VAM capture performance of the carbon composites, suggesting that our carbon composites have a great potential for site applications at coal mines because the cost and performance of solid adsorbents are critical factors to consider.

Comprehensive genetic exploration of skeletal dysplasia using targeted exome sequencing.

PURPOSE: The purpose of this study was to evaluate the clinical utility of targeted exome sequencing (TES) as a molecular diagnostic tool for patients with skeletal dysplasia. METHODS: A total of 185 patients either diagnosed with or suspected to have skeletal dysplasia were recruited over a period of 3 years. TES was performed for 255 genes associated with the pathogenesis of skeletal dysplasia, and candidate variants were selected using a bioinformatics analysis. All candidate variants were confirmed by Sanger sequencing, correlation with the phenotype, and a cosegregation study in the family. RESULTS: TES detected "confirmed" or "highly likely" pathogenic sequence variants in 74% (71 of 96) of cases in the assured clinical diagnosis category and 20.3% (13 of 64 cases) of cases in the uncertain clinical diagnosis category. TES successfully detected pathogenic variants in all 25 cases of previously known genotypes. The data also suggested a copy-number variation that led to a molecular diagnosis. CONCLUSION: This study demonstrates the feasibility of TES for the molecular diagnosis of skeletal dysplasia. However, further confirmation is needed for a final molecular diagnosis, including Sanger sequencing of candidate variants with suspected, poorly captured exons.Genet Med 18 6, 563-569.

Toxicokinetics of paraquat in Korean patients with acute poisoning.

To conduct a kinetic study of paraquat (PQ), we investigated 9 patients with acute PQ intoxication. All of them ingested more than 20 ml of undiluted PQ herbicide to commit suicide and arrived at our hospital early, not later than 7 h after PQ ingestion. The urine dithionite test for PQ in all of the nine patients was strongly positive at emergency room. Blood samples were obtained every 30 min for the first 2~3 h and then every 1 or 2 h, as long as the clinical progression was stable among the patients for 30 h after PQ ingestion. The area under the plasma concentration-time curve (AUCinf), which was extrapolated to infinity, was calculated using the trapezoidal rule. Toxicokinetic parameters, such as the terminal elimination half-life, apparent oral clearance, and apparent volume of distribution (Vd/F) were calculated. The maximum PQ concentration (Cmax) and the time to reach maximum PQ concentration (Tmax) were also obtained. Plasma PQ concentrations in nine patients were well described by a bi-exponential curve with a mean terminal elimination half-life of 13.1±6.8 h. Cmax and AUCinf were 20.8±25.7 mg/l and 172.5±160.3 h·mg/l, respectively. Apparent volume of distribution and apparent oral clearance were 50.9±61.3 l/kg and 173.4±111.2 l/h, respectively. There were a significant correlation (r =0.84; p<0.05) between the PQ amount ingested and Cmax. AUCinf also showed a significant correlation (r =0.83; p<0.05) with the PQ amount ingested. These correlations provide evidence that PQ has dose-linear toxicokinetic characteristics.

Skeletal overgrowth syndrome caused by overexpression of C-type natriuretic peptide in a girl with balanced chromosomal translocation, t(1;2)(q41;q37.1).

Chromosomal translocation of 2q37.1 just distal to the NPPC gene coding for C-type natriuretic peptide (CNP) and subsequent overproduction of CNP have been reported to cause a skeletal overgrowth syndrome. Loeys-Dietz syndrome (LDS) is one of marfanoid overgrowth syndromes, of which subtype IV is caused by haploinsufficiency of transforming growth factor beta 2 (TGFB2). We report on a girl with clinical phenotypes of overgrowth syndrome, including long and slim body habitus, macrodactyly of the big toe, scoliosis, ankle valgus deformity, coxa valga, slipped capital femoral epiphysis, and aortic root dilatation. Karyotyping revealed a balanced chromosomal translocation between 1q41 and 2q37.1, and the breakpoints could be mapped by targeted resequencing analysis. On chromosome 2q37.1, the translocation took place 200,365 bp downstream of NPPC, and serum level of the amino terminal of CNP was elevated. The contralateral site of translocation on chromosome 1q41 disrupted TGFB2 gene, presumed to cause its haploinsufficiency. This case supports the concept that NPPC is overexpressed because of the loss of a specific negative regulatory control in the normal chromosomal location, and demonstrates the effectiveness of targeted resequencing in the mapping of breakpoints.

Nephronophthisis 13: implications of its association with Caroli disease and altered intracellular localization of WDR19 in the kidney.

BACKGROUND: Nephronophthisis 13 (NPHP 13) is associated with mutations in the WDR19 gene, which encodes for a protein in the intraflagellar transport complex. Herein, we describe six additional cases accompanied by Caroli syndrome or disease. METHODS: Targeted exome sequencing covering 96 ciliopathy-related genes was performed for 48 unrelated Korean patients with a clinical suspicion of NPHP. Mutations were confirmed by Sanger sequencing. We evaluated the expression of WDR19 in the biopsied kidney by immunohistochemistry in patients and controls. RESULTS: We detected three (3/48, 6.3 %) unrelated index cases with WDR19 mutations. One of the cases involved two siblings with the same mutation. Later, we detected an additional index case with a similar phenotype of kidney and liver involvement by Sanger sequencing of WDR19. The p.R1178Q mutation was common in all patients. All of the six affected patients from four families progressed to chronic kidney disease. Of note, all six patients had Caroli syndrome or disease. Immunohistochemistry for WDR19 showed localized expression along the luminal borders of the renal tubular epithelium in controls, whereas it showed diffuse cytoplasmic staining in the affected patients. CONCLUSIONS: Caroli disease is a major extra-renal phenotype associated with mutations in WDR19 in the Korean population. In this study, we visually validated the expression pattern of mutant WDR19 protein in the kidneys of NPHP 13 patients. More data are needed to identify the true frequency of p.R1178Q. Functional studies including transfection assay will provide solid grounds for the pathogenicity of each mutation.

Atypical hemolytic uremic syndrome: Korean pediatric series.

BACKGROUND: Atypical hemolytic uremic syndrome (aHUS) is a rare disease with a genetic predisposition. Few studies have evaluated the disease in the Asian population. We studied a Korean pediatric cohort to delineate the clinical characteristics and genotypes. METHODS: A multicenter cohort of 51 Korean children with aHUS was screened for mutations using targeted exome sequencing covering 46 complement related genes. Anti-complement-factor-H autoantibody (anti-CFH) titers were measured. Multiplex ligation-dependent probe amplification assay was performed to detect deletions in the complement factor-H related protein genes (CFHR) in the patients as well as in 100 healthy Korean controls. We grouped the patients according to etiology and compared the clinical features using Mann-Whitney U-test and chi-squared test. RESULTS: Fifteen patients (group A, 29.7%) had anti-CFH, and mutations were detected in 11 (group B, 21.6%), including one with combined mutations. The remaining 25 (group C, 49.0%) were negative for both. The prevalence of anti-CFH was higher than the worldwide level. Group A had a higher onset age than group B, although the difference was not significant. Group B had the worst renal outcome. Gene frequencies of homozygous CFHR1 deletion were 73.3%, 2.7% and 1% in group A, group B + C and the control, respectively. CONCLUSIONS: The incidence of anti-CFH in the present Korean aHUS cohort was high. Clinical outcomes largely conformed to the previous reports. Although the sample size was limited, this cohort provides a reassessment of clinicogenetic features of aHUS in Korean children.

Chaperone stress 70 protein (STCH) binds and regulates two acid/base transporters NBCe1-B and NHE1.

Regulation of intracellular pH is critical for the maintenance of cell homeostasis in response to stress. We used yeast two-hybrid screening to identify novel interacting partners of the pH-regulating transporter NBCe1-B. We identified Hsp70-like stress 70 protein chaperone (STCH) as interacting with NBCe1-B at the N-terminal (amino acids 96-440) region. Co-injection of STCH and NBCe1-B cRNA into Xenopus oocytes significantly increased surface expression of NBCe1-B and enhanced bicarbonate conductance compared with NBCe1-B cRNA alone. STCH siRNA decreased the rate of Na(+)-dependent pHi recovery from NH4(+) pulse-induced acidification in an HSG (human submandibular gland ductal) cell line. We observed that in addition to NBCe1-B, Na(+)/H(+) exchanger (NHE)-dependent pHi recovery was also impaired by STCH siRNA and further confirmed the interaction of STCH with NHE1 but not plasma membrane Ca(2+) ATPase. Both NBCe1-B and NHE1 interactions were dependent on a specific 45-amino acid region of STCH. In conclusion, we identify a novel role of STCH in the regulation of pHi through site-specific interactions with NBCe1-B and NHE1 and subsequent modulation of membrane transporter expression. We propose STCH may play a role in pHi regulation at times of cellular stress by enhancing the recovery from intracellular acidification.

Enrichment of ventilation air methane (VAM) with carbon fiber composites.

Treatment of ventilation air methane (VAM) with cost-effective technologies has been an ongoing challenge due to its high volumetric flow rate with low and variable methane concentrations. In this work, honeycomb monolithic carbon fiber composites were developed and employed to capture VAM with a large-scale test unit at various conditions such as VAM concentration, ventilation air (VA) flow rate, temperature, and purging fluids. Regardless of inlet VAM concentrations, methane was captured at almost 100%. To regenerate the composites, the initial vacuum swing followed by combined temperature and vacuum swing adsorption (TVSA) was applied. It was found that initial vacuum swing is a control step for the final methane concentration having 5 or 11 times the VAM enrichment by one-step adsorption, which is, to our knowledge, the best performance achieved in VAM enrichment technologies worldwide. Five-time enriched VAM can be utilized as a principle fuel for lean burn turbine. Also, it can be further enriched by second step adsorption to more than 25% which then can be used for commercially available gas engines. In this way, the final product can be out of the methane explosive range (5-15%).

Autoantibodies in primary Sjögren's syndrome patients induce internalization of muscarinic type 3 receptors.

OBJECTIVES: Primary Sjögren's syndrome (pSS) is a systemic autoimmune disease characterized by lymphocyte infiltration into the salivary and lachrymal glands, leading to dry mouth and eyes. The presence of functional autoantibodies against muscarinic type 3 receptor (M3R) has been reported in pSS patients. However, the pathological role of anti-M3R autoantibodies in pSS salivary dysfunction remains controversial. METHODS: Purified IgGs were obtained from normal (control) and primary SS patients' sera (pSS IgG). Internalization of M3R and clathrin was analyzed by biochemical assay and immunofluorescence confocal microscopy using human submandibular gland (hSMG) cells. Cytoplasmic free Ca(2+) concentration ([Ca(2+)](i)) was measured by microspectrofluorimetry. RESULTS: Incubation of hSMG cells with pSS IgG (1mg/ml) significantly decreased M3R expression levels at the membrane. Carbachol-induced [Ca(2+)](i) transients (CICTs) in these cells were also inhibited by pSS IgG. In contrast to pSS IgG, control IgG had no effect on both the M3R expression level and CICTs. We found that binding of pSS IgG to M3R induces phosphorylation of the receptor, and that the pSS IgG-induced M3R internalization is prevented by the lysosomal inhibitor, chloroquine. In addition, pSS IgG decreased membrane clathrin expression, which was inhibited by atropine. Our immunofluorescence study further confirmed that pSS IgG induces a co-localization of M3R with clathrin and subsequent internalization of M3R. CONCLUSION: pSS IgG induces internalization of M3R partly through a clathrin-mediated pathway. The results suggest M3R internalization as a potential mechanism to explain the exocrinopathy seen in pSS patients.

IRBIT plays an important role in NHE3-mediated pHi regulation in HSG cells.

Expression of inositol-1,4,5-trisphosphate (IP3) receptor-binding protein (IRBIT) has been reported in epithelial cells. However, its role in pHi regulation is not well understood. In this study, we investigated the role of IRBIT in pHi regulation, mediated by Na(+)/H(+) exchangers (NHEs), in salivary glands. We measured pHi recovery from cell acidification in BCECF-loaded salivary HSG cells. Western blot and co-immunoprecipitation (CO-IP) assays were also performed, showing that NHE1, 2 and 3 are expressed, and IRBIT binds to NHE3. HOE642, a specific NHE1 blocker, inhibited pHi recovery, but 40% pH(i) recovery was still observed even at the highest concentration of HOE642. Furthermore, pretreatment of the cells with siIRBIT significantly inhibited pHi recovery, indicating that NHE3 potentially plays a role in pHi recovery as well. The amount of membrane-localized NHE3 and its interaction with IRBIT are also significantly increased by cell acidification. In addition, we found that Ste20p-related proline alanine-rich kinase (SPAK) reverses the effect of IRBIT on membrane NHE3 translocation. Taken together, we conclude that IRBIT plays an important role in pHi regulation, mediated by NHE3, and further regulated by SPAK.

Development and Validation of an Online Calculator to Predict Proximal Junctional Kyphosis After Adult Spinal Deformity Surgery Using Machine Learning.

OBJECTIVE: Although adult spinal deformity (ASD) surgery aims to restore and maintain alignment, proximal junctional kyphosis (PJK) may occur. While existing scoring systems predict PJK, they predominantly offer a generalized 3-tier risk classification, limiting their utility for nuanced treatment decisions. This study seeks to establish a personalized risk calculator for PJK, aiming to enhance treatment planning precision. METHODS: Patient data for ASD were sourced from the Korean spinal deformity database. PJK was defined a proximal junctional angle (PJA) of ≥ 20° at the final follow-up, or an increase in PJA of ≥ 10° compared to the preoperative values. Multivariable analysis was performed to identify independent variables. Subsequently, 5 machine learning models were created to predict individualized PJK risk post-ASD surgery. The most efficacious model was deployed as an online and interactive calculator. RESULTS: From a pool of 201 patients, 49 (24.4%) exhibited PJK during the follow-up period. Through multivariable analysis, postoperative PJA, body mass index, and deformity type emerged as independent predictors for PJK. When testing machine learning models using study results and previously reported variables as hyperparameters, the random forest model exhibited the highest accuracy, reaching 83%, with an area under the receiver operating characteristics curve of 0.76. This model has been launched as a freely accessible tool at: (https://snuspine.shinyapps.io/PJKafterASD/). CONCLUSION: An online calculator, founded on the random forest model, has been developed to gauge the risk of PJK following ASD surgery. This may be a useful clinical tool for surgeons, allowing them to better predict PJK probabilities and refine subsequent therapeutic strategies.

Full-Endoscopic Lumbar Discectomy Approach Selection: A Systematic Review and Proposed Algorithm.

STUDY DESIGN: A systematic review of the literature to develop an algorithm formulated by key opinion leaders. OBJECTIVE: This study aimed to analyze currently available data and propose a decision-making algorithm for full-endoscopic lumbar discectomy for treating lumbar disc herniation (LDH) to help surgeons choose the most appropriate approach [transforaminal endoscopic lumbar discectomy (TELD) or interlaminar endoscopic lumbar discectomy (IELD)] for patients. SUMMARY OF BACKGROUND DATA: Full-endoscopic discectomy has gained popularity in recent decades. To our knowledge, an algorithm for choosing the proper surgical approach has never been proposed. MATERIALS AND METHODS: A systematic review of the literature using PubMed and MeSH terms was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Patient samples included patients with LDH treated with full-endoscopic discectomy. The inclusion criteria were interventional research (randomized and nonrandomized trials) and observation research (cohort, case-control, case series). Exclusion criteria were case series and technical reports. The criteria used for selecting patients were grouped and analyzed. Then, an algorithm was generated based on these findings with support and reconfirmation from key expert opinions. Data on overall complications were collected. Outcome measures included zone of herniation, level of herniation, and approach (TELD or IELD). RESULTS: In total, 474 articles met the initial screening criteria. The detailed analysis identified the 80 best-matching articles; after applying the inclusion and exclusion criteria, 53 articles remained for this review. CONCLUSIONS: The proposed algorithm suggests a TELD for LDH located in the foraminal or extraforaminal zones at upper and lower levels and for central and subarticular discs at the upper levels considering the anatomic foraminal features and the craniocaudal pathology location. An IELD is preferred for LDH in the central or subarticular zones at L4/L5 and L5/S1, especially if a high iliac crest or high-grade migration is found.

Transforaminal Endoscopic Discectomy for Hard or Calcified Lumbar Disc Herniation: A New Surgical Technique and Clinical Outcomes.

OBJECTIVE: Hard or calcified discs are often adherent to surrounding nerve tissue. The whole herniated disc is difficult to remove by pulling part of the hernia mass, which makes obtaining good results through endoscopic treatment difficult. The purpose of this study was to describe the details of the transforaminal endoscopic lumbar discectomy technique for a hard or calcified disc and report the clinical results. METHODS: From October 2016 to June 2019, 43 consecutive cases diagnosed as hard or calcified lumbar disc herniation at our institution and treated with transforaminal endoscopic discectomy were evaluated. Endoscopic decompression was performed in patients with hard or calcified lumbar disc herniation. RESULTS: The preoperative visual analog scale score for leg pain (mean ± standard deviation) was 7.09 ± 1.74. The score improved to 2.55 ± 1.35 at 1 week postoperatively, 1.88 ± 1.29 at 4 weeks postoperatively, and 1.58 ± 1.0 at 26 weeks postoperatively (P < 0.01 for all). The preoperative Oswestry Disability Index (mean ± standard deviation) was 55.4 ± 23.04, which improved to 30.89 ± 13.64 at 1 week postoperatively, 23.08 ± 11.64 at 4 weeks postoperatively, and 16.42 ± 9.76 at 26 weeks postoperatively (P < 0.01 for all). Two patients developed a dural laceration. Both patients were discharged after several hours of observation. None of the patients had postoperative infection, epidural hematoma, or delayed neurological deterioration. CONCLUSIONS: Transforaminal endoscopic discectomy could be an effective treatment method for a selected group of patients with hard or calcified lumbar disc herniation.

Transforaminal Endoscopic Decompression for Lumbar Spinal Stenosis: A Novel Surgical Technique and Clinical Outcomes.

OBJECTIVE: Transforaminal endoscopic treatment has been reported to be an effective treatment option in patients with lumbar disc herniation. However, it is rarely performed for spinal stenosis because of the limitation of endoscopic working mobility caused by the exiting nerve root and foraminous bony structure. The objective of this study was to describe a novel transforaminal endoscopic decompression technique for spinal stenosis and report the clinical results. METHODS: From October 2015 to October 2016, 30 consecutive cases were diagnosed as lateral recess stenosis in our institution and underwent transforaminal endoscopic decompression. Visual analog scale (VAS) of back and leg pain and the Oswestry Disability Index (ODI) were measured preoperatively and at follow-up. RESULTS: The mean ± SD value of preoperative VAS leg pain score was 7.6 ± 1.17. The score improved to 2.2 ± 1.11 at 1 week postoperatively, 1.73 ± 0.96 at 4 weeks postoperatively, and 1.63 ± 0.95 at 26 weeks postoperatively (P < 0.01). The mean ± SD value of the preoperative ODI score was 65.69 ± 14.22. The score improved to 24.29 ± 11.89 at 1 week postoperatively, 21.25 ± 9.25 at 4 weeks postoperatively, and 15.62 ± 10.49 at 26 weeks postoperatively (P < 0.01). There were no patients with postoperative infection, dural tear, delayed neurologic deterioration, or conversion to open surgery. CONCLUSIONS: Transforaminal endoscopic decompression under local anesthesia could be an effective treatment method for the selected group of patients with spinal stenosis.

Transforaminal full-endoscopic lumbar discectomy in obese patients.

BACKGROUND: Obese patients are at risk of complications such as slower wound healing and increased infection rates after spinal surgery. Transforaminal full-endoscopic lumbar discectomy (ELD) has advantages over conventional microdiscectomy because it decreases perioperative complications and increases favorable clinical outcomes. No clinical studies have reported ELD in obese patients. The purpose of this study is to evaluate the clinical outcomes of transforaminal ELD in obese patients. METHODS: Obesity is defined as a body mass index (BMI) of more than 30 kg/m2. Our study included 21 obese patients and 27 normal BMI patients treated by posterolateral transforaminal ELD for radiating pain caused by a single-level lumbar disc herniation with more than 2 years of follow-up. Clinical chart reviews and telephone surveys were conducted. Clinical and functional outcomes using VAS and ODI, perioperative complications, and reherniation were evaluated. RESULTS: Overall clinical and functional outcomes were improved during postoperative follow-up evaluation. There were no immediate perioperative complications, such as infection or durotomy in both groups. In obese group, three patients had late reherniations. Of these, 2 patients had tolerable pain and showed good recovery with conservative treatment; 1 patient who had undergone ELD for recurrent disc herniation underwent open microdiscectomy. In control group, two patients had early reherniation and underwent open microdiscectomy and one patient with late reherniation showed good recovery with conservative treatment. CONCLUSION: In select cases, ELD is an effective, safe, and minimally invasive technique for obese patients. It decreases perioperative morbidity and allows for both early mobilization and early return to work. LEVEL OF EVIDENCE: level 3b.

Visual changes after gamma knife surgery for optic nerve tumors. Report of three cases.

Tumors involving the optic nerve (optic glioma, optic nerve sheath meningioma) are benign but difficult to treat. Gamma knife surgery (GKS) may be a useful treatment. The authors present data obtained in three such cases and record the effects of GKS.

Comparison of clinical and radiological outcomes after automated open lumbar discectomy and conventional microdiscectomy: a prospective randomized trial.

OBJECTIVE: Microdiscectomy (MD) is the gold standard for surgical discectomy. As a minimally invasive discectomy, automated open lumbar discectomy (AOLD) is designed to preserve annular integrity and disc height as well as effectively remove herniated disc and degenerated disc material. However, there have been no prospective clinical studies comparing their effectiveness. The study was designed to compare clinical and radiological outcomes after AOLD with those of MD. METHODS: Seventy-eight patients were evaluated for unilateral leg pain with the presence of disc herniation on magnetic resonance imaging (MRI) scans at a single attributable level. Sixty-two patients were enrolled; 33 patients (53%) were randomly assigned to the AOLD group and the remaining 29 patients (47%) were assigned to the MD group. Follow-up assessment was performed for 19 of the AOLD patients and 17 of the MD patients. The average follow-up period was 20 months. Clinical and functional outcomes were assessed using VAS and ODI scores. Change of disc height (DH), instability, and disc degeneration were assessed from radiographs, while Modic change and reherniation were assessed using MRI scans. RESULTS: Postoperative VAS scores for leg pain and ODI scores for function were significantly improved in both groups. Postoperative VAS for back pain tended to decrease in the MD group but the decrease was statistically insignificant (P = 0.081). The postoperative VAS for back pain was significantly reduced in the AOLD group (P = 0.012). Patients from the MD group showed greater DH reduction than the AOLD group (P = 0.049). The MD group experienced greater disc degeneration and Modic change than the AOLD group. Follow-up MRI revealed 2 cases of reherniation in the AOLD group; 1 case was symptomatic, the other was asymptomatic. CONCLUSIONS: AOLD showed comparable clinical and radiological outcomes to conventional MD. AOLD preserves the central disc and removes only the loose degenerative disc fragments that are the main cause of reherniation by small annulotomy. Our results suggest that preservation of the central disc prevents loss of disc height and segmental instability, which is related to postdiscectomy back pain.