***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
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    Input: BACKGROUND : Transmuscular tubular diskectomy has been introduced to increase the rate of recovery , although evidence is lacking . OBJECTIVE : To evaluate the 2-year results of tubular diskectomy compared with conventional microdiskectomy . METHODS : Three hundred twenty-eight patients with persistent leg pain caused by lumbar disk herniation were r and omly assigned to undergo tubular diskectomy ( 167 patients ) or conventional microdiskectomy ( 161 patients ) . Main outcome measures were scores from Rol and -Morris Disability Question naire for Sciatica , Visual Analog Scale for leg pain and low-back pain , and Likert self-rating scale of global perceived recovery . RESULTS : On the basis of intention-to-treat analysis , there was no significant difference between tubular diskectomy and conventional microdiskectomy in Rol and -Morris Disability Question naire for Sciatica scores during 2 years after surgery ( between-group mean difference [ Δ ] = 0.6 ; 95 % confidence interval [ CI ] , −0.3 - 1.6 ) . Patients treated with tubular diskectomy reported more leg pain ( Δ = 3.3 mm ; 95 % CI , 0.2 - 6.2 ) and more low-back pain ( Δ = 3.0 mm ; 95 % CI , −0.2 - 6.3 ) than those patients treated with conventional microdiskectomy . At 2 years , 71 % of patients assigned to tubular diskectomy documented a good recovery vs 77 % of patients assigned to conventional microdiskectomy ( odds ratio , 0.76 ; 95 % CI , 0.45 - 1.28 ; P = .35 ) . Repeated surgery rates within 2 years after tubular diskectomy and conventional microdiskectomy were 15 % and 10 % , respectively ( P = .22 ) . CONCLUSION : Tubular diskectomy and conventional microdiskectomy result ed in similar functional and clinical outcomes . Patients treated with tubular diskectomy  reported more leg pain and low-back pain , although the differences were small and not clinical ly relevant Objective Percutaneous endoscopic lumbar discectomy ( PELD ) and microdiscectomy with the microscope endoscopic tubular retractor system(METRx-MD ) are considered popular minimally invasive surgery ( MIS ) methods for the treatment of lumbar disc herniation . Many authors have also reported good clinical outcomes of these methods , but there are few comparative studies of them . This report compares the clinical outcomes of PELD and METRx-MD for lumbar disc herniation as MIS methods and discusses the efficacy of PELD . Methods Seventy-two patients who had undergone single-level unilateral discectomy using two different methods , PELD and METRx-MD , between 2009 and 2011 were given a follow-up examination prospect ively . Thirty-seven of these patients underwent  discectomy using PELD , and the remaining 35 patients underwent discectomy using METRx-MD . In addition to the general parameters , clinical outcomes were assessed as specific parameters using the Visual Analogue Scale ( VAS ) score , the Oswestry Disability Index ( ODI ) , the Short-form 36 ( SF-36 ) , and the return-to-work time . Results Sixty-seven percent ( 25/37 ) of the patients in the PELD group and 74%(26/35 ) in the METRx-MD group were included in follow-up more than 6 months post-operatively . The mean improvements in the VAS scores for the back pain , leg pain , and ODI were 2.6 , 4.8 , and 30.1 % for the PELD group and 2.8 , 4.6 , and 33.2 % for the METRx-MD group , respectively . The SF-36 physical health component subscale score improved from 40.6 pre-operatively to 68.3 at the last follow-up for the PELD group post-operatively , and from 48.5 to 65.1 in the mental component subscale ( METRx-MD group : from 34.4 to 66.5 and from 44.87 to 56.7 ) . Complications occurred in 3/37 patients in the PELD group and in 2/35 patients in the METRx-MD group in the peri-operative period . The mean return-to-work times were 37.5 days in the PELD group and 42.5 days in the METRx-MD group . Conclusion The outcomes for the PELD group are comparable to those for the METRx-MD group . It can thus be concluded that PELD for lumbar disk herniations may be performed safely and effectively . Also , PELD can be considered one of the treatment modalities of lumbar disk herniation Background : Highly migrated intracanal disk herniation is not among the exclusion criteria of the interlaminar microendoscopic diskectomy ( MED ) procedure . The goal of this prospect i ve , r and omized , controlled study was to compare the effect of the size of the skin incision and the method of h and ling the multifidus muscle on the results of the interlaminar MED procedure versus conventional microdiskectomy in retrieving highly migrated intracanal disk herniations . Methods : Seventy-three patients with highly migrated intracanal lumbar disk herniations treated with either minimal incision , multifidus-sparing MED or conventional microdiskectomy were observed for 2 years . Primary ( clinical ) outcomes data included the results of the Numerical Rating Scale ( NRS ) for back and leg pain and the Oswestry Disability Index ( ODI ) to quantify pain and disability , respectively . Secondary objective outcomes data included surgical time , blood loss , postoperative analgesics , length of hospital stay , time to return to work , the rates of revision surgery complications , and the results of the patient satisfaction index ( PSI ) and the modified MacNab criteria . Results : At final follow-up , relief of leg pain was statistically significant for both groups . NRS back pain , ODI , PSI , and the modified MacNab criteria showed no improvement in the conventional microdiskectomy group . Secondary outcomes data in the MED group were significantly better than those for the control group . Conclusions : Highly migrated intracanal lumbar disk herniations can be sufficiently retrieved using minimal incision , multifidus-sparing MED , which is an effective alternative to conventional microdiskectomy . The minimal skin incision and multifidus-sparing approach of the MED had a positive effect on clinical outcomes , which were stable throughout the 2-year follow-up period . Level of Evidence : Therapeutic level In the GRADE approach , r and omized trials start as high- quality evidence and observational studies as low- quality evidence , but both can be rated down if most of the relevant evidence comes from studies that suffer from a high risk of bias . Well-established limitations of r and omized trials include failure to conceal allocation , failure to blind , loss to follow-up , and failure to appropriately consider the intention-to-treat principle . More recently recognized limitations include stopping early for apparent benefit and selective reporting of outcomes according to the results . Key limitations of observational studies include use of inappropriate controls and failure to adequately adjust for prognostic imbalance . Risk of bias may vary across outcomes ( e.g. , loss to follow-up may be far less for all-cause mortality than for quality of life ) , a consideration that many systematic review s ignore . In deciding whether to rate down for risk of bias -- whether for r and omized trials or observational studies -- authors should not take an approach that averages across studies . Rather , for any individual outcome , when there are some studies with a high risk , and some with a low risk of bias , they should consider including only the studies with a lower risk of bias Study Design . Prospect i ve , r and omized , controlled study of patients with lumbar disc herniations , operated either in a full-endoscopic or microsurgical technique .  Objective . Comparison of results of lumbar discectomies in full-endoscopic interlaminar and transforaminal technique with the conventional microsurgical technique . Summary of Background Data . Even with good results , conventional disc operations may result in subsequent damage due to trauma . Endoscopic techniques have become the st and ard in many areas because of the advantages they offer intraoperatively and after surgery . With the transforaminal and interlaminar techniques , 2 full-endoscopic procedures are available for lumbar disc operations . Methods . One hundred seventy-eight patients with full-endoscopic or microsurgical discectomy  underwent follow-up for 2 years . In addition to general and specific parameters , the following measuring instruments were used : VAS , German version North American Spine Society Instrument , Oswestry Low-Back Pain Disability Question naire . Results . After surgery 82 % of the patients no longer had leg pain , and 14 % had occasional pain . The clinical results were the same in both groups . The recurrence rate was 6.2 % with no difference between the groups . The full-endoscopic techniques brought significant advantages in the following areas : back pain , rehabilitation , complications , and traumatization . Conclusion . The clinical results of the full-endoscopic technique are equal to those of the microsurgical technique . At the same time , there are advantages in the operation technique and reduced traumatization . With the surgical devices and the possibility of selecting an interlaminar or posterolateral to lateral transforaminal procedure , lumbar disc herniations outside and insidethe spinal canal can be sufficiently removed using the full-endoscopic technique , when taking the appropriate criteria into account . Full-endoscopic surgery is a sufficient and safe supplementation and alternative to microsurgical procedures OBJECTIVE Minimal access surgery as a less invasive alternative to st and ard macro- and microsurgical approaches is becoming increasingly popular in the management of traumatic and degenerative spine diseases . However , data is lacking if minimal access spine surgery is indeed beneficial . This prospect i ve r and omized study was conducted to compare efficiency , safety , and outcome of st and ard open microsurgical discectomy ( SOMD ) for lumbar disc herniation with microsurgical discectomy using an 11.5 mm trocar system for minimal access to the spine . METHODS Sixty patients were r and omized to two groups of 30 patients each . Group 1 was treated by SOMD , and Group 2 was treated by minimal access microsurgical discectomy ( MAMD ) . Perioperative parameters and pre- and postoperative clinical findings including sensory or motor deficits and pain according to the visual analog scale , Oswestry Disability Index scores , and Short Form-36 results were assessed . All patients were followed for at least 6 months postoperatively ( mean , 16 mo ) . RESULTS Preoperatively , no statistically significant intergroup differences could be detected proving the comparability of both groups . Postoperatively , significant improvement of neurological symptoms and pain as measured by the visual analog scale , Oswestry Disability Index , and Short Form-36 scores could be achieved in both groups . In regard to operative time , intraoperative blood loss , and complication rate , slightly better results were observed in the MAMD group . CONCLUSIONS OMD and MAMD allow achievement of significant improvement of pain and neurological deficits in patients with lumbar disc herniations . Differences in operative time , blood loss , and complication rates were statistically not significant in MAMD compared with SOMD , indicating that , at least in lumbar disc surgery , minimal access trocar techniques are a viable alternative to st and ard spinal approaches Background : Intervertebral disc herniation is a major cause of low back pain . Several treatment methods are available for lumbar disc herniation including Chemonucleolysis , open surgery , nucleoplasty , laser disc decompression , and intradiscal electrothermal therapy . The high prevalence of lumbar disc herniation necessitates a minimally invasive yet effective treatment method . In this study , we compared the outcomes of open surgery and nucleoplasty method in patients with single lumbar disc herniation . Material s and Methods : This study was a noninferiority r and omized clinical trial conducted in one of the University Hospitals of Isfahan Medical University ; The Alzahra Hospital . About 200 patients with the diagnosis of lumbar disc herniation were recruited and were assigned to either the treatment or control groups using block r and omization . One group received open surgery and the other group received nucleoplasty as the method of treatment . Patients were revisited at 14 days , 1 , 2 , 3 months , and 1-year after surgery and were assessed for the following variables : Lower back pain , lower limb pain , common complications of surgery ( e.g. , discitis , infection and hematoma ) and recurrence of herniation . Results : The mean ( st and ard deviation ) severity of low back pain was reduced from 6.92 ( 2.5 ) to 3.43 ( 2.3 ) in the nucleoplasty group ( P = 0.04 ) and from 7.5 ( 2.2 ) to 3.04 ( 1.61 ) in the discectomy group ( P = 0.73 ) . Between group difference was not statistically significant ( P = 0.44 ) , however , time and treatment interaction was significant ( P = 0.001 ) . The level of radicular pain evaluated 1 year after treatment was reduced from 8.1 ( 1.2 ) to 2.9 ( 1.2 ) ( P = 0.004 ) and from 7.89 ( 2.1 ) to 3.6 ( 2.5 ) ( P = 0.04 ) in the discectomy and the nucleoplasty groups respectively , significant interaction between time and treatment options was observed ( P < 0.001 ) while there was no significant difference between two treatment groups ( P = 0.82 ) . Conclusion : Our results show that while nucleoplasty is as effective as open discectomy in the treatment of lumbar disc herniation , it is also less invasive with higher patient compliance . T 
    Output:
    
Compared with the OD/MD , results of this meta- analysis suggest that PELD has a lower risk of overall complications and a lower risk of complications necessitating conservative treatment .