Microendoscopic Discectomy Group Research Articles

Clinical assessment of thoracolumbar transpedicle screw placement via posterior lamina in microendoscopic discectomy

Objective To explore feasibility, safety and efficacy of thoracolumbar transpedicle screw placement via posterior lamina aided by microendoscopic discectomy (MED). Methods A retrospective study was performed of the patients with thoracolumbar fracture (from T12 to L2) who had been treated simply with minimally invasive endoscopic transpedicle screwing at our department from July 2008 to September 2013. Of them, 61 received placement of ordinary transpedicle screws via posterior lamina aided by MED (the MED group), and 57 percutaneous placement of hollow transpedicle screws of Sextant system (the Sextant group), and 51 percutaneous placement of hollow transpedicle screws of Viper system (the Viper group). The 3 groups were compatible in preoperative general data, showing no significant differences (P>0.05). The 3 groups were compared in terms of surgical incision, intraoperative bleeding loss, surgery duration, fluoroscopy frequency, surgical convenience, visual analog scale (VAS) score, hospital stay, total medical expenses and complications. Satisfaction degree of the patients was also evaluated. Results This series was followed up from 6 to 24 months. No significant differences were found between the 3 groups in surgical incision, intra-operative bleeding loss, surgery duration, VAS score, hospital stay, complications, or satisfaction degree of the patients (P>0.05). Compared with the Sextant and Viper groups, the MED needed less fluoroscopy frequency, lower medical expenses, and no special devices or implants, though it was more complicated. Conclusions Placement of transpedicle screws via posterior lamina aided by MED has advantages of direct visualization of pedicle screw insertion, simplified operation of C-Arm X-ray machine, surgical safety, and controlled surgical risks. Key words: Surgical procedures, minimally invasive; Spinal fractures; Fracture fixation, internal; Microendoscopic discectomy

Full-Endoscopic Technique Discectomy Versus Microendoscopic Discectomy for the Surgical Treatment of Lumbar Disc Herniation

Background: Full-endoscopic technique discectomy (FED) or microendoscopic discectomy (MED) are 2 widely used minimally invasive procedures for the treatment of lumbar disc herniation. However, there is insufficient literature regarding the differences between these 2 surgical procedures. Objective: To compare the clinical outcomes of 2 different minimally invasive methods—fullendoscopic technique discectomy and microendoscopic discectomy—in the surgical treatment of lumbar disc herniation. Study Design: Retrospective study. Setting: Inpatient surgery center. Methods: Data form 65 patients with lumbar disc herniation treated with one of 2 minimally invasive procedures were retrospectively analyzed. Patients were divided into 2 groups according to surgical method: the FED group (n = 35) and the MED group (n = 30). Surgery time, time kept in bed after surgery, duration of postoperative hospital stay, visual analog scale (VAS; 0 – 10), and Oswestry Disability index (ODI; 0 – 100%) were assessed and compared between the 2 groups. Results: There were no significant differences in the preoperative data between the 2 groups (P > 0.05). VAS and ODI scores improved significantly postoperatively in both groups (P < 0.05). Surgery time was longer in the FED group than in the MED group (P < 0.05). However, the FED group was superior to the MED group, with less time in bed, shorter hospital stay, and lower VAS scores one day postoperatively (P < 0.05). There were no significant differences in VAS or ODI scores at one, 3, and 12 months after surgery between the 2 groups (P > 0.05). Limitations: This is a retrospective study with a relatively short follow-up period. Conclusions: Although the clinical outcomes of the 2 surgical techniques were similar, the FED had the advantages of quicker postoperative recovery and more immediate effect. Key words: Full-endoscopic, microendoscopic, discectomy, lumbar disc herniation, minimally invasive, surgical treatment

Comparison of Open Discectomy with Microendoscopic Discectomy in Lumbar Disc Herniations: Results of a Randomized Controlled Trial

Introduction Despite all of the technical refinements, surgical treatment of herniated discs still remains controversial. The objective of the current prospective randomized study was to compare the outcome of patients with persistent sciatica secondary to lumbar disc herniation treated with either open discectomy (OD) or microendoscopic discectomy (MED) technique. Patients and Methods We performed a prospective controlled randomized study of 40 patients with sciatica caused by lumbar disc herniations nonresponsive to conservative treatment who underwent OD or MED with a 24-month follow-up period. Pre- and postoperative neurological status, pain, and functional outcome were evaluated. Other studied variables were the duration of the procedure, blood loss, time of hospital stay, and time to return to work. Statistical analysis with a p value less than 0.005 was performed. Results The only statistically significant differences found were for size of the incision, length of hospital stay, and operative time. The former two were greater in the OD group ( p < 0.01 and p = 0.05, respectively), and the latter was greater in the MED group ( p < 0.01). Conclusion The few parameters that were found to be statistically significant between the groups did not affect the overall outcome. In the current series, the final clinical and neurological results were similarly satisfactory in both the OD and the MED groups.

Outcomes of Microendoscopic Discectomy and Percutaneous Transforaminal Endoscopic Discectomy for the Treatment of Lumbar Disc Herniation: A Comparative Retrospective Study.

Study DesignRetrospective, case control evaluation of 86 patients who underwent microendoscopic discectomy (MED) and percutaneous transforaminal endoscopic discectomy (PTED) for the treatment of lumbar disc herniation (LDH).PurposeTo evaluate the safety and the outcomes of MED and PTED for the treatment of LDH.Overview of LiteratureMED and PTED are minimally invasive surgical techniques for lower back pain. Studies to date have shown that MED and PTED are safe and effective treatment modalities for LDH.MethodsA retrospective study was performed in patients with LDH treated with MED (n=50) and transforaminal endoscopic discectomy (PTED; n=36) in our hospital. All patients were followed-up with self-evaluation questionnaires, Oswestry disability index (ODI), medical outcomes study 36-item short form health survey and MacNab criteria. All the patients in both groups were followed up to 12 months after the operation.ResultsODI questionnaire responses were not statistically different between the MED and PTED groups (53.00 vs. 48.72) before treatment. Average scores and minimal disability after 5 days to 12 months of follow-up were 4.96 in the MED group and 3.61 in the PTED group. According to MacNab criteria, 92.0% of the MED group and 94.4% of the PTED group had excellent or good results with no significant difference.ConclusionsThere was no significant difference between MED and PTED outcomes. Further large-scale, randomized studies with long-term follow-up are needed.

Surgical technique and effectiveness of microendoscopic discectomy for large uncontained lumbar disc herniations: a prospective, randomized, controlled study with 8 years of follow-up.

There is a long-held concept among spine surgeons that endoscopic lumbar discectomy procedures are reserved for small-contained disc herniation; 8-year follow-up has not been reported. The purpose of this study is to assess microendoscopic discectomy (MED) in patients with large uncontained lumbar disc herniation (the antero-posterior diameter of the extruded fragment is 6-12 mm or more on axial cuts of MRI) and report long-term outcome. One hundred eighty-five patients with MED or standard open discectomy underwent follow-up for 8 years. Primary (clinical) outcomes data included Numerical Rating Scale (NRS) for back and leg symptoms and Oswestry Disability Index (ODI) to quantify pain and disability, respectively. Secondary (objective) outcomes data included operative time, blood loss, postoperative analgesics, length of hospital stay, time to return to work, reoperation and complication rate, patient satisfaction index (PSI), and modified (MacNab) criteria. At the end of the follow-up, the leg pain relief was statistically significant for both groups. NRS back pain, ODI, PSI and MacNab criteria showed significant deterioration for control group. Secondary outcomes data of MED group were significantly better than the control group. Large, uncontained, lumbar disc herniations can be sufficiently removed using MED which is an effective alternative to open discectomy procedures with remarkable long-term outcome. Although the neurological outcome of the two procedures is the same, the morbidity of MED is significantly less than open discectomy. Maximum benefit can be gained if we adhere to strict selection criteria. The optimum indication is single- or multi-level radiculopathy secondary to a single-level, large, uncontained, lumbar disc herniation.

Systematic review of microendoscopic discectomy for lumbar disc herniation

Systematic review. To search and analyse randomised controlled trials (RCTs) published since the Cochrane review by Gibson and Waddell (2007) comparing microendoscopic discectomy (MED) with open discectomy (OD) or microdiscectomy (MD) and to assess whether MED improves patient-reported outcomes. Discectomy for symptomatic herniated lumbar discs is an effective operative treatment. A number of operative techniques exist including OD, MD, and MED. A 2007 Cochrane review identified OD as an effective treatment for symptom improvement, and found sufficient evidence for MD. However, evidence for MED was lacking. A systematic review of Medline and Embase was carried out. Aiming to identify RCTs carried out after 2007, which compared OD with MD and MED which reported the Oswestry disability index (ODI) as an outcome. Four RCTs were identified. None of the studies found a significant difference in the ODI scores between study groups at any time point. Three studies compared MED to OD and one compared OD, MD, and MED. The largest study reported an increased number of severe complications in the MED group. There is some evidence to suggest that MED performed by surgeons skilled in the technique in tertiary referral centres is as effective as OD.

A Novel Microendoscopically Assisted Approach for the Treatment of Recurrent Lumbar Disc Herniation: Transosseous Discectomy Surgery

Microendoscopic discectomy (MED) is still regarded as contraindicated for the treatment of recurrent lumbar disc herniation by many surgeons. Moreover, the presence of epidural scar tissue makes surgical manipulation difficult. To successfully remove the herniated disc in such cases, an open technique with a wide exposure may be required. We devised a new minimally invasive endoscopic approach, which is using a transosseous route. This is a retrospective review of a consecutive case series to examine the operative and clinical results of this new approach. Fifty-seven patients who underwent surgery for recurrent lumbar disc herniation were divided into two groups based on the operative procedure. Thirty patients underwent microendoscopic transosseous discectomy (TD) and 27 underwent MED. We graded operative results and clinical outcomes using the Japanese Orthopaedic Association (JOA) score for low-back pain before surgery and 1 year after surgery and compared the scores of the two groups. No conversion to open procedure was necessary in either group. The mean TD operative time was 89.2 minutes with a mean intraoperative blood loss of 16.5 mL. Mean MED operative time was 92.0 minutes with a mean blood loss of 19.3 mL. There were two dural tears in the MED group, and one tear was combined with a fracture of the inferior articular process. No dural tears occurred in the TD group. No patients in either group had experienced re-recurrence of lumbar disc herniation at the time of the last follow-up. The JOA score improved significantly after surgery in both groups (p < 0.001). TD is a safe and effective surgical approach for the treatment of recurrent lumbar disc herniation. Operative time, intraoperative blood loss, and clinical results compare favorably with MED.

Microendoscopic discectomy versus microscopic discectomy for treatment of lumbar disc herniations: a systematic review of randomized controlled trials

Objective To compare the effectiveness and safety of microendoscopic discectomy (MED) versus microscopic discectomy (MD) for treatment of lumbar disc herniations. Methods Key words were defined as microendoscopic discectomy, microscopic discectomy, lumbar disc herniation, etc. The electronic databases (PubMed, EMbase, Cochrane Central Register of Controlled Trials, CNKI, and Wanfang) were searched in order to retrieve randomized controlled trials (RCTs) about comparing MED and MD for the treatment of lumbar disc herniations. We also applied manual searching to screen out relevant journals. Data were extracted and evaluated by two reviewers independently. The quality of the included trails was evaluated by Jadad scales. Cochrane collaboration's RevMan 5.0.24 were used for data analysis. Results Four RCTs involving 1069 patients were included in the Meta⁃analysis. Results of Meta⁃analysis showed that: the Oswestry dysfunctional index (ODI) after operation in MED group was not significantly different from that in the MD group (MD = ⁃ 0.170, 95%CI: ⁃ 3.590-3.260; P = 0.920); dural tears in MED group were higher than those of MD group (RR = 3.040, 95%CI: 1.170-7.890; P = 0.020); there were no significant difference between MED group and MD group in terms of root injury (RR = 5.130, 95% CI: 0.890-29.420; P = 0.070) and recurrent herniation (RR = 2.320, 95%CI: 0.970-5.520; P = 0.060); there were significant difference between MED group and MD group in terms of surgical time (MD = 10.780, 95%CI: 7.180-14.370; P = 0.000), size of incision (MD = ⁃ 0.950, 95%CI: ⁃ 1.840-0.070; P = 0.030) and length of hospital stay (MD = 0.210, 95%CI: ⁃ 0.080-0.340; P = 0.002). There was no significant difference between MED group and MD group in terms of blood loss (MD = 27.420, 95% CI: ⁃ 8.840-63.680; P = 0.140). Conclusion According to present knowledge, the two techniques were found to be effective for the treatment of lumbar disc herniations, but recurrent herniations were significantly more common in MED group. As for the safety of the two techniques, dural tears and root injuries were significantly more common in MED group. Because of the limitation of the quality and amount for the RCTs included, the results of this systematic review should be prudently cited, and more high quality RCTs are needed to be performed. DOI：10.3969/j.issn.1672⁃6731.2012.04.006

The Results of Percutaneous Intradiscal High-Pressure Injection of Saline in Patients with Extruded Lumbar Herniated Disc: Comparison with Microendoscopic Discectomy

Intradiscal high-pressure injection of saline (IDHP) is a noninvasive procedure for a lumbar intervertebral disc extrusion and an alternative treatment to surgery, such as microendoscopic discectomy (MED). The purpose of this study was to compare the representative outcomes of IDHP with MED in terms of pain relief, reduction of disability, and risk of complications. Forty-five patients with primarily radicular pain due to an extrusion type disc herniation who underwent either IDHP (N = 24) or MED (N = 21) were enrolled in the study. The visual analog pain scale (VAS) and the Japanese Orthopedic Association (JOA) scoring system for the treatment of low-back disorders were assessed at pretreatment, 2 weeks posttreatment, and JOA was again taken 3 months posttreatment. Patients were asked to choose their satisfaction from four alternatives, "excellent,""good,""fair," and "poor," 3 months after treatment. Mean VAS decreased from 65.1 to 18.8 mm in the IDHP group, and from 80.6 to 16.5 in the MED group. Mean JOA recovery rates at 3 months posttreatment were 67.2 and 75.2, and patients with "excellent" or "good" results were 73.7% and 78.6% in the IDHP and in MED, respectively. IDHP produced significant effects on patients with radicular pain, leading to the improvement of VAS and JOA. Although IDHP displayed slightly less efficacy than MED, IDHP appears to be an alternative as a nonoperative treatment for a lumbar intervertebral disc extrusion.

Complications of endoscopic microdiscectomy using the EASYGO! system: is there any difference with conventional discectomy during the learning-curve period?

Microendoscopic discectomy (MED) is emerging as a minimally invasive alternative to conventional microsurgical discectomy (MSD). EASYGO! is a new system for spinal endoscopy that claims smooth transition from MSD to MED, with a reduced learning curve period. The aims of this study were to describe the complications that appeared during the learning curve period of MED and to compare their incidence with the rate and type of complications that occurred during a simultaneous non-randomised series of standard MSDs. Between July 2009 and December 2010, 138 patients underwent scheduled first-time discectomy in our institution, 37 using an MED approach and 101 by a conventional MSD. A MED learning curve was obtained by plotting every case with its respective operative time. Complications, length of hospital stay, need of further surgery and outcome were prospectively recorded in both groups. The mean operative time was 66 min for the MSD group and 100 min for the MED group, although for the last 14 cases of the latter group the time was reduced. Curve-fitting techniques showed that the inverse equation, ƒ(x) = 122.12/x + 73.05, had the best correlation between case number and operative time. The learning curve was overcome after the 30th case. Complications occurred in 9.8 % of the MSD group and 8.1 % of the MED group (P = 0.49). Average length of hospital stay was 2.36 days for the MED group and 3.36 days for the MSD group (P = 0.01). The procedure successfully relieved patient symptoms in 68.63 % of the MSD group and 89.92 % of the MED group. No revision surgery was required in the MED group, but it was necessary in ten patients of the MSD group. Between 25 and 30 cases are needed to reach the learning curve's asymptote of MED. Even during this initial learning period MED is a safe procedure, with comparable results to those obtained with conventional MSD and with a similar complication rate. The key points for reducing intraoperative complications are an adequate expertise in MSD, a precise selection of initial cases, a proper surgical planning and a careful technique, which are mandatory to avoid unnecessary neurological injury in an otherwise secure surgical approach.

Comparison of clinical outcomes between microsurgical lumbar discectomy and microendoscopic discectomy

Objective To make a comparison between microsurgical lumbar discectomy(MSLD) and microendoscopic discectomy(MED) in terms of methods,feathers,and effectiveness for lumbar disc herniation (LDH).Methods A prospective clinical review was conducted.From January 2006 to December 2009,900patients with single segment lumber disc herniation were randomly divided into the MSLD group and the MED group.There were 450 patients in each group.Comparison would be made in terms of the length of skin incision,the operative time,amount of bleeding,incidence of complication,duration of hospitalization,the time of recovery to ordinary work or life,pre- and post-operative assessment based on the criteria of visual analogue scales (VAS),and the Oswestry disability index(ODI).Results The mean lengths of skin incision were (3.8±1.1) cm and (2.4±0.7) cm for MSLD and MED respectively; the operative time were (51.0±14.2) min and (62.0±16.3) min; and the blood loss were (60±35) ml and (106±43) ml,which showed a significant difference (P＜0.05).There was no significant differences in terms of the hospitalization time and the time of recovery to ordinary work or life between the two groups (P＞0.05).The results of VAS and ODI of two groups also showed no significant difference at final follow-up (P＞0.05).As for the complications,the incidence of dural tear,acute hematomas of sacrospinalis,nerve roots and cauda equina injury and recurrence in MSLD group were much lower than that of MED group (P＜0.01).There was no incidence of wrong segment,greater artery injury,or postoperative infection in each group.Conclusion The clinical effects of both minimal invasive methods are satisfactory.However,MSLD has advantages of simpler maneuvering,shorter learning curve,and less complication than MED. Key words: Lumbar vertebrae; Endoscopy; Intervertebral disk displacement; Diskectomy

Comparison of Lumbar disc herniation surgery by two different methods

Objective To compare the clinical value of approach of microendoscopic discectomy( MED) and open discectomy (OD) in patients with lumbar disc herniation (LDH). Methods 100 patients with lumbar disc herniation according to the different surgical approaches were divided into MED group (n =50) and OD group (n =50) , The indicators of blood loss,operative time,hospitalization time,nerve root injury,relieve sciatica were observed in two groups. Results The rate of excellent in MED group (90. 0% ) were higher than OD group (80. 0% ) (χ~2 = 3.99, P < 0. 05); The indicators of blood loss, operative time, hospitalization time in MED group were less than OD group (t = 2.412,t=2.498,<=2.518,t =2.416,all P<0.05). Conclusion Compared with OD group,MED offer a similar short-term clinical outcome,but with smaller incision,less tissue trauma and quicker recovery. Key words: Intervenebral disk displacement; Minimally invasive operation; Microsurgery

Long-Term Outcomes of Patients with Lumbar Disc Herniation Treated with Percutaneous Discectomy: Comparative Study with Microendoscopic Discectomy

We assessed the long-term outcomes of patients with lumbar disc herniation treated with percutaneous lumbar discectomy (PLD) or microendoscopic discectomy (MED). A retrospective study was performed in consecutive patients with lumbar disc herniation treated with PLD (n = 129) or MED (n = 101) in a single hospital from January 2000 to March 2002. All patients were followed up with MacNab criteria and self-evaluation questionnaires comprising the Oswestry Disability Index and Medical Outcomes Study 36-Item Short-Form Health Survey. Several statistical methods were used for analyses of the data, and a p value of <0.05 was considered to be statistically significant. A total of 104 patients (80.62%) with PLD and 82 patients (81.19%) with MED were eligible for analyses, with a mean follow-up period of 6.64 +/- 0.67 years and 6.42 +/- 0.51 years, respectively. There were no significant differences between the two groups in age, number of lesions, major symptoms and physical signs, and radiological findings. According to the MacNab criteria, 75.96% in the PLD group and 84.15% in the MED group achieved excellent or good results, respectively, this was statistically significant (p = 0.0402). With the Oswestry Disability Index questionnaires, the average scores and minimal disability, respectively, were 6.97 and 71.15% in the PLD group and 4.89 and 79.27% in the MED group. Total average scores of Medical Outcomes Study 36-Item Short-Form Health Survey were 75.88 vs. 81.86 in PLD group vs. MED group (p = 0.0582). The cost and length of hospitalization were higher or longer in MED group, a statistically significant difference (both p < 0.0001). Long-term complications were observed in two patients (2.44%) in the MED group, no such complications were observed in the PLD group. Both PLD and MED show an acceptable long-term efficacy for treatment of lumbar disc herniation. Compared with MED patients, long-term satisfaction is slightly lower in the PLD patients; complications, hospitalization duration, and costs in PLD group are also lower.

The efficacy of microendoscopic discectomy in reducing iatrogenic muscle injury

The objective of this study was to evaluate the invasiveness of microendoscopic discectomy (MED) in comparison with microscopic discectomy (MD) by measuring serum levels of creatine phosphokinase (CPK)-MM and lactate dehydrogenase (LDH)-5, and by comparing visual analog scale (VAS) scores of postoperative pain. This study included a group of 15 patients who underwent surgery using MED and 15 patients who underwent surgery using MD, both for single-level unilateral herniated nucleus pulposus. The CPK-MM and LDH-5 levels were measured at admission and after 1, 3, and 5 days postoperatively. Pain assessment was recorded using scores raging from 0 to 10 on a subjective VAS at admission and at 1, 3, and 5 days postoperatively. The mean CPK-MM levels were lower for the MED group than for the MD group at both 3 (576.1 +/- 286.3 IU/L compared with 968.1 +/- 377.8 IU/L) and 5 days (348.1 +/- 231.0 IU/L compared with 721.7 +/- 463.2) postoperatively (p < 0.05). The mean VAS scores for postoperative back pain were lower in the MED group than in the MD group, both at 1 (3.3 +/- 2.3 compared with 5.8 +/- 1.5) and 5 days (1.9 +/- 1.1 compared with 3.6 +/- 1.1) postoperatively (p < 0.01). The MED procedure is less invasive than MD, and causes less muscle damage and less back pain.

COMPARISON OF OPEN DISCECTOMY WITH MICROENDOSCOPIC DISCECTOMY IN LUMBAR DISC HERNIATIONS

We compared the intra- and postoperative differences, as well as the final outcome of patients with herniated lumbar discs who underwent either open discectomy (OD) or microendoscopic discectomy (MED). We performed a prospective controlled randomized study of 40 patients with sciatica caused by lumbar disc herniations nonresponsive to conservative treatment who underwent OD or MED with a 24-month follow-up period. Pre- and postoperative neurological status, pain, and functional outcome were evaluated. Other studied variables were the duration of the procedure, blood loss, time of hospital stay, and time to return to work. Statistical analysis with a P value less than 0.005 was carried out. The only statistically significant differences found were for size of the incision, length of hospital stay, and operative time. The former two were greater in the OD group (P < 0.01 and P = 0.05, respectively), and the latter was greater in the MED group (P < 0.01). The few parameters that were found to be statistically significant between the groups did not affect the overall outcome. In the current series, the final clinical and neurological results were similarly satisfactory in both the OD and the MED groups.

Interleukin-6 Protein Expression Is More Important Than Interleukin-6 mRNA Levels in Assessing Surgical Invasiveness

Interleukin-6 (IL-6) protein has been recognized as a sensitive marker of surgical stress response. However, little is known about the clinical significance of IL-6 mRNA levels as a marker of surgical stress. This study aims to examine the role of IL-6 mRNA expression in comparing the tissue invasiveness of microendoscopic discectomy (MED) and open discectomy (OD). Twenty-three consecutive patients were randomly selected to undergo either MED or OD. The total RNA was extracted from the peripheral whole blood of patients at pre-op and at 1, 2, 4, 8, 12 h post-op. The real-time reverse transcription polymerase chain reaction (RT-PCR) using the SYBR Green I fluorescence dye and the 2(-DeltaDeltaCt) method was adopted to measure the IL-6 gene expression. The quantitative changes of IL-6 mRNA expression in MED and OD patients at different times post-op differed significantly, P = 0.04. Experimental results indicate that the changes in IL-6 mRNA expression in OD and MED groups varied significantly at 1 h, 12 h post-op, 10.26-fold versus 4.42-fold and 52.15-fold versus 26.78-fold increase, respectively. Although IL-6 mRNA expression demonstrated an earlier difference than protein levels at 1 h post-op, IL-6 mRNA levels were found to be significantly affected after surgical procedures. Furthermore, compared with our enzyme-linked immunosorbent assay data, no significant correlation existed between IL-6 mRNA and protein levels at any post-op time interval. We conclude that IL-6 mRNA expression using RT-PCR to extract the total RNA from a patient's peripheral whole blood is more sensitive than protein levels but can be significantly affected by surgical procedures. The enzyme-linked immunosorbent assay data on IL-6 protein expression are more consistent and significant than IL-6 mRNA levels in comparing tissue invasiveness between MED and OD.

Microendoscopic Discectomy for Lumbar Disc Herniation

A retrospective review involving 873 consecutive cases of lumbar disc herniation treated by microendoscopic discectomy (MED) was conducted and a mean 28-month follow-up was performed. The purpose of this study was to describe the MED technique for lumbar disc herniation and report long-time outcome and complications. The conception of MED was introduced in 1997. Long-time outcome has not been described. A total of 873 consecutive patients with lumbar disc herniation were treated with the METRx system. Oswestry Disability Index (ODI) was used to quantify pain relief. The degree of pain and disability was also measured by visual analog scale (VAS) and modified MacNab criteria. A control group of 358 patients treated with standard open discectomy was used for comparison. There was significant improvement in the mean preoperative and postoperative VAS and ODI score for the MED and open groups, and there was no statistical difference of the pain improvement between the two groups. For the MED group, average length of hospital stay was 4.8 days; mean time to return to work or normal activities was 15 days; average operative blood loss per level was 44 mL. These were significantly less than open group. MED is an effective microendoscopic system with fine long-term outcome in treating lumbar disc herniation. The endoscopic approach allows smaller incisions and less tissue trauma, compared with standard open microdiscectomy. Strict adherence to well-defined preoperative selection criteria could ensure optimal postoperative outcome.

Microendoscopic Discectomy Compared with Standard Microsurgical Discectomy for Treatment of Uncontained or Large Contained Disc Herniations

Minimally invasive spinal techniques have been developed for years in an attempt to minimize trauma. However, most endoscopic techniques have been unable to address uncontained or large contained disc herniations. The aim of this prospective study was to compare the results of microendoscopic discectomy (MED) and microsurgical discectomy in the treatment of patients with uncontained or large contained disc herniations. An independent observer reviewed the treatment of 28 patients. The study group included 14 consecutive patients who underwent MED and 14 consecutive patients who underwent microsurgical discectomy for radicular pain secondary to uncontained or large contained disc herniations during the same period. Patients were followed up for an average of 12 months. They were assessed by use of Oswestry disability questionnaire and low back pain outcome score. The average outcome score improvement was of clinical significance in both patient groups. No difference in the scores was found between the two groups. Patients in the MED group required less postoperative analgesia during their stay. One patient in the MED group had a dural tear. MED is at least as effective as microsurgical discectomy for treatment of uncontained or large contained disc herniations, although the advantages over the open technique are short lived and did not reach significance. Nonetheless, for the surgeon accustomed to endoscopic techniques, MED seems to be a safe procedure.

Objective assessment of reduced invasiveness in MED

Microendoscopic discectomy (MED) has been accepted as a minimally invasive procedure for lumbar discectomy because of the small skin incision and short hospital stay required for this surgery. However, there are few objective laboratory data to confirm the reduced systemic responses in the early phase after this procedure. In order to substantiate the reduced invasiveness of MED compared to microdiscectomy (MD) or procedures involved in one-level unilateral laminotomy, the invasiveness of each surgical procedure was evaluated by measuring serum levels of biochemical parameters reflective of a post-operative inflammatory reaction and damage to the paravertebral muscles. Thirty-three patients who underwent lumbar discectomy or one-level unilateral laminotomy (MED in 15 cases, MD in 11 cases and one-level unilateral laminotomy in 7 cases with lumbar spinal canal stenosis) were included in this study. The serum levels of C-reactive protein (CRP) and creatine phosphokinase (CPK) were measured at 24 h after operation. Interleukin-6 (IL-6) and Interleukin-10 (IL-10) were measured at 2, 4, 8 and -24 h following the surgery to monitor the inflammatory response to the respective surgery. The post-operative serum CRP levels from both the MD and MED groups were significantly lower than those from the open laminotomy group. However, there was no significant difference in these serum levels between the MED and MD groups. The levels of IL-6 and IL-10 in the MED group during the first post-operative day were also significantly lower than those in the laminotomy group. When the MED and MD groups were compared, the IL-6 levels in the MED group were lower than in MD group at 2, 4 and 8 h after surgery, but the differences were not statistically significant. However, the level was significantly lower in the MED group at 24 h after surgery. In terms of IL-10, no significant difference was noted between the MED and MD groups over the study period. The changes in serum levels of post-operative inflammatory: markers (CRP, IL-6 and IL-10) in the early phase indicated reduced inflammatory reactions in MED as well as in MD when compared with classical open unilateral laminotomy. These data draw a direct link between the lower level of the inflammatory response and reduced invasiveness of MED. However, an indicator for muscle damage (CPK) appeared not to be affected by the type of surgical procedure used to correct disc herniation.

Less systemic cytokine response in patients following microendoscopic versus open lumbar discectomy

The magnitude of the tissue damage from surgery impacts the trauma response. This response is proportional to the severity of surgical stress. Systemic cytokines are recognized as markers of postoperative tissue trauma. Microendoscopic discectomy (MED) recently has become popular for treating lumbar disc herniations, and is associated with favorable clinical outcomes compared with open discectomy (OD). This study postulates that MED is a less traumatic procedure, and therefore has a lower surgical stress response compared to OD. In this study, a quantitative comparison of the overall effects of surgical trauma resulting from MED and OD was performed through analyzing patient systemic cytokines response. From April, 2002 to June, 2003, 22 consecutive patients who had symptomatic lumbar disc herniations were prospectively randomized to undergo either intracanalicular MED ( N = 10) or OD ( N = 12). In this study, the Vertebroscope System (Zeppelin, Pullach, Germany) was used to perform the endoscopic discectomy procedure in all MED patients. Serum levels of tumor necrosis factor-α (TNF-α), Interleukin-1β (IL-1β), Interleukin-6 (IL-6), and Interleukin-8 (IL-8) were measured before surgery and at 1, 2, 4, 8 and 24 h after surgery using an enzyme-linked immunosorbent assay. Serum C-reactive protein (CRP) was measured at the same time interval. The results showed the MED patients had shorter postoperative hospital stay (mean, 3.57 ± 0.98 vs. 5.92 ± 2.39 days, p = 0.025) and less intraoperative blood loss (mean, 87.5 ± 69.4 vs. 190 ± 115 ml, p = 0.042). The operating length, including the set-up time, was longer in the MED group (mean, 109 ± 35.9 vs. 72.1 ± 17.8 min, p = 0.01). The mean size of skin incision made for the MED patients was 1.86 ± 0.13 cm (range 1.7–2.0 cm); and 6.3 ± 0.98 cm for the OD patients (range 5.5–8 cm), p = 0.001. The patients’ pain severity of the involved limbs on 10-point Visual Analog Scale before operation in MED group was 7.5 ± 0.3 (range 6–9) and 8 ± 0.2 (range 7–9) in OD group, p = 0.17; and after surgery, 1.5 ± 0.2 (range 1–2) in MED group and 1.4 ± 0.1 (range 1–3) in OD group, p = 0.91. CRP levels peaked at 24 h in both groups, and OD patients displayed a significantly greater postoperative rise in serum CRP (mean, 27.78 ± 15.02 vs. 13.84 ± 6.25 mg/l, p = 0.026). Concentrations of TNF-α, IL-1β, and IL-8 were detected only sporadically. Serum IL-6 increased less significantly following MED than after OD. In the MED group, IL-6 level peaked 8 h after surgery, with the response statistically less than in the open group (mean, 6.27 ± 5.96 vs. 17.18 ± 11.60 pg/ml, p = 0.025). A statistically significant correlation was identified between IL-6 and CRP values ( r = 0.79). Using the modified MacNab criteria, the clinical outcomes were 90% satisfactory (9/10) in MED patients and 91.6% satisfactory (11/12) in OD patients at a mean 18.9 months (range 10–25) follow-up. Based on the current data, surgical trauma, as reflected by systemic IL-6 and CRP response, was significantly less following MED than following OD. The difference in the systemic cytokine response may support that the MED procedure is less traumatic. Moreover, our MED patients had achieved satisfactory clinical outcomes as the OD patients at a mean 18.9 months follow-up after surgery.