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1.  An Analysis of the Prognostic Factors Affecing the Clinical Outcomes of Conventional Lumbar Open Discectomy : Clinical and Radiological Prognostic Factors 
Asian Spine Journal  2010;4(1):23-31.
Study Design
This is a retrospective study.
We wanted to examine the clinical and radiological prognostic factors affecting the postoperative clinical outcome of patients with lumbar disc herniation and who underwent open discectomy.
Overview of Literature
Conventional open discectomy has been widely used as a treatment regimen for the management of lumbar disc herniation. Still, much controversy exists regarding the factors that affect the postoperative clinical outcomes.
The current study was conducted on 40 patients who were diagnosed with lumbar disc herniation by the senior surgeon of our department from March 2004 to June 2007. These patients were refractory to conservative treatment and they could be followed up for more than one year following their surgical treatments. Preoperatively, after postoperative year 1 and at the final follow-up, a comparison was made for the Oswestry disability index (ODI) scores and the visual analogue scale (VAS) scores that indicated low back pain and radiating pain. For identifying prognostic factors, an analysis was also performed for such factors as age, gender, the operated level, the duration of preoperative low back pain and radiating pain, a smoking history, the body mass index and whether the surgery was revision or the primary operation. A radiological analysis, based on the preoperative plain flexion-extension radiography, was performed for the presence of mild segmental instability of < 3 mm, spondylolysis and disc space narrowing. Pfirrmann's degenerative grade of the disc, the degree of herniation and whether a herniation was central or massive on the magnetic resonance imaging scans.
At the final follow-up, the ODI was significantly higher in the cases of revision as compared with the cases of primary operation. The female gender also had a tendency for a poor ODI as compared with that of the men, but this had only borderline statistical significance. There was significant correlation between the preoperative ODI and the preoperative VAS indicating radiating pain. At a final follow up, the low back pain VAS score was significantly lower in the extruded cases as compared with that of the protruded or sequestrated cases.
Following an analysis for detecting the prognostic factors of open discectomy, the final clinical outcome was found to be poor for the revision surgery cases. In regard to the type of herniation, the degree of low back pain was relatively lower at a final follow-up for the extruded cases as compared with that for the protruded or sequestrated cases. Open discectomy surgery should be performed after evaluating the patients' various prognostic factors that could affect the final clinical outcome.
PMCID: PMC2900165  PMID: 20622951
Lumbar disc herniation; Open discectomy; Clinical outcome; Prognostic factor
2.  Failed back surgery syndrome: the role of symptomatic segmental single-level instability after lumbar microdiscectomy 
European Spine Journal  2004;13(3):193-198.
Segmental instability represents one of several different factors that may cause or contribute to the failed back surgery syndrome after lumbar microdiscectomy. As segmental lumbar instability poses diagnostic problems by lack of clear radiological and clinical criteria, only little is known about the occurrence of this phenomenon following primary microdiscectomy. Retrospectively, the records of 2,353 patients were reviewed according to postoperative symptomatic segmental single-level instability after lumbar microdiscectomy between 1989 and 1997. Progressive neurological deficits increased (mean of 24 months; SD: 12, range 1–70) after the initial surgical procedure in 12 patients. The mean age of the four men and eight women was 43 years (SD: 6, range 40–77). The main symptoms and signs of secondary neurological deterioration were radicular pain in 9 of 12 patients, increased motor weakness in 6 of 12 patients and sensory deficits in 4 of 12 patients. All 12 symptomatic patients had radiological evidence of segmental changes correlating with the clinical symptoms and signs. All but one patient showed a decrease in the disc height greater than 30% at the time of posterior spondylodesis compared with the preoperative images before lumbar microdiscectomy. All patients underwent secondary laminectomy and posterior lumbar sponylodesis. Postoperatively, pain improved in 8 of 9 patients, motor weakness in 3 of 6 patients, and sensory deficits in 2 of 4 patients. During the follow-up period of 72±7 months, one patient required a third operation to alleviate spinal stenosis at the upper end of the laminectomy. Patients with secondary segmental instability following microdiscectomy were mainly in their 40s. Postoperative narrowing of the intervertebral space following lumbar microdiscectomy is correlated to the degree of intervertebral disc resection. It can therefore be concluded that (1) patients in their 40s are prone to postoperative narrowing of the intervertebral disc space and hence subsequent intervertebral instability and (2) that a small extent of intervertebral disc resection and preservation of the “segmental frame” may be beneficial in those patients. The present study demonstrated for the first time that the degree of extensive operative techniques in microdiscectomy increased the risk of subsequent segmental instability. In addition, narrowing of the intervertebral space of more than 30% represents a clear radiological sign of segmental instability.
PMCID: PMC3468142  PMID: 14752624
Microdiscectomy; Disc herniation; Segmental instability; Failed back surgery syndrome; Discectomy; Lumbar spine; Spinal instrumentation
3.  Comparison of Percutaneous Endoscopic Lumbar Discectomy and Open Lumbar Microdiscectomy for Recurrent Disc Herniation 
The purpose of this study was to compare clinical and radiological outcomes of percutaneous endoscopic lumbar discectomy (PELD) and open lumbar microdiscectomy (OLM) for recurrent disc herniation.
Fifty-four patients, who underwent surgery, either PELD (25 patients) or repeated OLM (29 patients), due to recurrent disc herniation at L4-5 level, were divided into two groups according to the surgical methods. Excluded were patients with sequestrated disc, calcified disc, severe neurological deficit, or instability. Clinical outcomes were assessed using Visual Analogue Scale (VAS) score and Oswestry Disability Index (ODI). Radiological variables were assessed using plain radiography and/or magnetic resonance imaging.
Mean operating time and hospital stay were significantly shorter in PELD group (45.8 minutes and 0.9 day, respectively) than OLM group (73.8 minutes and 3.8 days, respectively) (p < 0.001). Complications occurred in 4% in PELD group and 10.3% in OLM group in the perioperative period. At a mean follow-up duration of 34.2 months, the mean improvements of back pain, leg pain, and functional improvement were 4.0, 5.5, and 40.9% for PELD group and 2.3, 5.1, and 45.0% for OLM group, respectively. Second recurrence occurred in 4% after PELD and 10.3% after OLM. Disc height did not change after PELD, but significantly decreased after OLM (p = 0.0001). Neither sagittal rotation angle nor volume of multifidus muscle changed significantly in both groups.
Both PELD and repeated OLM showed favorable outcomes for recurrent disc herniation, but PELD had advantages in terms of shorter operating time, hospital stay, and disc height preservation.
PMCID: PMC2803265  PMID: 20062565
Reherniation; Discectomy; Lumbar spine
4.  Minimally invasive surgical procedures for the treatment of lumbar disc herniation 
In up to 30% of patients undergoing lumbar disc surgery for herniated or protruded discs outcomes are judged unfavourable. Over the last decades this problem has stimulated the development of a number of minimally-invasive operative procedures. The aim is to relieve pressure from compromised nerve roots by mechanically removing, dissolving or evaporating disc material while leaving bony structures and surrounding tissues as intact as possible. In Germany, there is hardly any utilisation data for these new procedures – data files from the statutory health insurances demonstrate that about 5% of all lumbar disc surgeries are performed using minimally-invasive techniques. Their real proportion is thought to be much higher because many procedures are offered by private hospitals and surgeries and are paid by private health insurers or patients themselves. So far no comprehensive assessment comparing efficacy, safety, effectiveness and cost-effectiveness of minimally-invasive lumbar disc surgery to standard procedures (microdiscectomy, open discectomy) which could serve as a basis for coverage decisions, has been published in Germany.
Against this background the aim of the following assessment is:
Based on published scientific literature assess safety, efficacy and effectiveness of minimally-invasive lumbar disc surgery compared to standard procedures. To identify and critically appraise studies comparing costs and cost-effectiveness of minimally-invasive procedures to that of standard procedures. If necessary identify research and evaluation needs and point out regulative needs within the German health care system. The assessment focusses on procedures that are used in elective lumbar disc surgery as alternative treatment options to microdiscectomy or open discectomy. Chemonucleolysis, percutaneous manual discectomy, automated percutaneous lumbar discectomy, laserdiscectomy and endoscopic procedures accessing the disc by a posterolateral or posterior approach are included.
In order to assess safety, efficacy and effectiveness of minimally-invasive procedures as well as their economic implications systematic reviews of the literature are performed. A comprehensive search strategy is composed to search 23 electronic databases, among them MEDLINE, EMBASE and the Cochrane Library. Methodological quality of systematic reviews, HTA reports and primary research is assessed using checklists of the German Scientific Working Group for Health Technology Assessment. Quality and transparency of cost analyses are documented using the quality and transparency catalogues of the working group. Study results are summarised in a qualitative manner. Due to the limited number and the low methodological quality of the studies it is not possible to conduct metaanalyses. In addition to the results of controlled trials results of recent case series are introduced and discussed.
The evidence-base to assess safety, efficacy and effectiveness of minimally-invasive lumbar disc surgery procedures is rather limited:
Percutaneous manual discectomy: Six case series (four after 1998)Automated percutaneous lumbar discectomy: Two RCT (one discontinued), twelve case series (one after 1998)Chemonucleolysis: Five RCT, five non-randomised controlled trials, eleven case seriesPercutaneous laserdiscectomy: One non-randomised controlled trial, 13 case series (eight after 1998)Endoscopic procedures: Three RCT, 21 case series (17 after 1998)
There are two economic analyses each retrieved for chemonucleolysis and automated percutaneous discectomy as well as one cost-minimisation analysis comparing costs of an endoscopic procedure to costs for open discectomy.
Among all minimally-invasive procedures chemonucleolysis is the only of which efficacy may be judged on the basis of results from high quality randomised controlled trials (RCT). Study results suggest that the procedure maybe (cost)effectively used as an intermediate therapeutical option between conservative and operative management of small lumbar disc herniations or protrusions causing sciatica. Two RCT comparing transforaminal endoscopic procedures with microdiscectomy in patients with sciatica and small non-sequestered disc herniations show comparable short and medium term overall success rates. Concerning speed of recovery and return to work a trend towards more favourable results for the endoscopic procedures is noted. It is doubtful though, whether these results from the eleven and five years old studies are still valid for the more advanced procedures used today. The only RCT comparing the results of automated percutaneous lumbar discectomy to those of microdiscectomy showed clearly superior results of microdiscectomy. Furthermore, success rates of automated percutaneous lumbar discectomy reported in the RCT (29%) differ extremely from success rates reported in case series (between 56% and 92%).
The literature search retrieves no controlled trials to assess efficacy and/or effectiveness of laser-discectomy, percutaneous manual discectomy or endoscopic procedures using a posterior approach in comparison to the standard procedures. Results from recent case series permit no assessment of efficacy, especially not in comparison to standard procedures. Due to highly selected patients, modi-fications of operative procedures, highly specialised surgical units and poorly standardised outcome assessment results of case series are highly variable, their generalisability is low.
The results of the five economical analyses are, due to conceptual and methodological problems, of no value for decision-making in the context of the German health care system.
Aside from low methodological study quality three conceptual problems complicate the interpretation of results.
Continuous further development of technologies leads to a diversity of procedures in use which prohibits generalisation of study results. However, diversity is noted not only for minimally-invasive procedures but also for the standard techniques against which the new developments are to be compared. The second problem refers to the heterogeneity of study populations. For most studies one common inclusion criterion was "persisting sciatica after a course of conservative treatment of variable duration". Differences among study populations are noted concerning results of imaging studies. Even within every group of minimally-invasive procedure, studies define their own in- and exclusion criteria which differ concerning degree of dislocation and sequestration of disc material. There is the non-standardised assessment of outcomes which are performed postoperatively after variable periods of time. Most studies report results in a dichotomous way as success or failure while the classification of a result is performed using a variety of different assessment instruments or procedures. Very often the global subjective judgement of results by patients or surgeons is reported. There are no scientific discussions whether these judgements are generalisable or comparable, especially among studies that are conducted under differing socio-cultural conditions. Taking into account the weak evidence-base for efficacy and effectiveness of minimally-invasive procedures it is not surprising that so far there are no dependable economic analyses.
Conclusions that can be drawn from the results of the present assessment refer in detail to the specified minimally-invasive procedures of lumbar disc surgery but they may also be considered exemplary for other fields where optimisation of results is attempted by technological development and widening of indications (e.g. total hip replacement).
Compared to standard technologies (open discectomy, microdiscectomy) and with the exception of chemonucleolysis, the developmental status of all other minimally-invasive procedures assessed must be termed experimental. To date there is no dependable evidence-base to recommend their use in routine clinical practice. To create such a dependable evidence-base further research in two directions is needed: a) The studies need to include adequate patient populations, use realistic controls (e.g. standard operative procedures or continued conservative care) and use standardised measurements of meaningful outcomes after adequate periods of time. b) Studies that are able to report effectiveness of the procedures under everyday practice conditions and furthermore have the potential to detect rare adverse effects are needed. In Sweden this type of data is yielded by national quality registries. On the one hand their data are used for quality improvement measures and on the other hand they allow comprehensive scientific evaluations. Since the year of 2000 a continuous rise in utilisation of minimally-invasive lumbar disc surgery is observed among statutory health insurers. Examples from other areas of innovative surgical technologies (e.g. robot assisted total hip replacement) indicate that the rise will probably continue - especially because there are no legal barriers to hinder introduction of innovative treatments into routine hospital care. Upon request by payers or providers the "Gemeinsamer Bundesausschuss" may assess a treatments benefit, its necessity and cost-effectiveness as a prerequisite for coverage by the statutory health insurance. In the case of minimally-invasive disc surgery it would be advisable to examine the legal framework for covering procedures only if they are provided under evaluation conditions. While in Germany coverage under evaluation conditions is established practice in ambulatory health care only (“Modellvorhaben") examples from other European countries (Great Britain, Switzerland) demonstrate that it is also feasible for hospital based interventions. In order to assure patient protection and at the same time not hinder the further development of new and promising technologies provision under evaluation conditions could also be realised in the private health care market - although in this sector coverage is not by law linked to benefit, necessity and cost-effectiveness of an intervention.
PMCID: PMC3011322  PMID: 21289928
5.  Recurrent lumbar disc herniation: A prospective comparative study of three surgical management procedures 
Asian Journal of Neurosurgery  2013;8(3):139-146.
The optimal surgical treatment of recurrent lumbar disc herniation is controversial.
To compare prospectively the clinical outcomes of surgical treatment of recurrent lumbar disc herniation by three different methods; discectomy alone, discectomy with transforaminal lumbar interbody fusion (TLIF), and diecectomy with posterolateral fusion (PLF), regardless of the postoperative radiological findings.
Study Design:
This is a prospective, randomized, comparative study.
Materials and Methods:
This is a prospective, randomized, comparative study on 45 patients with first time recurrent lumbar disc herniation. Patients were evaluated clinically by using the criteria of the Japanese Orthopedic Association's evaluation system for low back pain syndrome (JOA score). The patients were classified into three groups: Group A; patients who had revision discectomy alone, group B; patients who had revision discectomy with TLIF, and group C; patients who had revision discectomy with PLF. The mean follow-up period was 37 (±7.85 STD) months.
The mean overall recovery rate was 87.2% (±19.26 STD) and the satisfactory rate was 88.9%. Comparison between the three groups showed no significant difference with regard to the mean total postoperative JOA score, recovery rate, and satisfactory rate. However, the postoperative low back pain was significantly higher in group A than that of group B and C. Two patients in group A required further revision surgery. The incidences of dural tear and postoperative neurological deficit were higher in group A. The intraoperative blood loss and length of operation were significantly less in group A. The total cost of the procedure was significantly different between the three groups, being least in group A and highest in group B. There was no significant difference between the three groups with regard to the length of postoperative hospital stay.
Revision discectomy is effective in patients with recurrent lumbar disc herniation. Fusion with revision discectomy improves the postoperative low back pain, decreases the intraoperative risk of dural tear or neural damage and decreases the postoperative incidence of mechanical instability or re-recurrence. TLIF and PLF have comparable results when used with revision discectomy, but PLF has significantly less total cost than TLIF.
PMCID: PMC3877500  PMID: 24403956
Anterior lumbar interbody fusion; posterior lumbar interbody fusion; posterolateral fusion; recurrent lumbar disc herniation; transforaminal lumbar interbody fusion
6.  Comparison of outcomes between conventional lumbar fenestration discectomy and minimally invasive lumbar discectomy: an observational study with a minimum 2-year follow-up 
Different surgical techniques for lumbar discectomy are in vogue. This study compares the outcomes of two techniques for lumbar discectomy, viz. micro lumbar discectomy (LD) and conventional fenestration discectomy.
Materials and methods
Sixty-six patients who had single-level 'virgin’ lumbar disc herniation with unilateral radicular symptoms were included. Of these, 39 had undergone MLD while 27 had undergone fenestration. Outcomes were measured using the visual analogue scale (VAS) for back and leg pain, Japanese Orthopedic Association (JOA) score, Roland-Morris score (RM) improvement and North American Spine Society (NASS) score. All quantitative data were summarised using mean and standard deviation, and qualitative data using proportions. Significance of differences across the two groups in terms of mean scores was assessed using independent sample t test, and the improvement within the same groups was measured using paired t test. Multiple linear regression analysis was done to assess independent predictors of improvement.
The MLD group showed statistically better outcomes with regard to improvement in JOA score at 6 weeks, 6 months and 2 years. Mean (SD) VAS for lower back ache at 6 weeks, 6 months, and 2 years was better for the MLD group. But the difference noted in VAS for leg pain was not statistically significant across the groups (P = 0.133). The improvement noted in JOA at 2 years postoperatively compared to the preoperative score was 13.67 (2.89) in the MLD group and 12.11 (3.30) in the macrodiscectomy group (P = 0.046).
The mean (SD) RM improvement for the MLD group was 79.24% (8.96%) vs 71.72% (16.53), P = 0.02, in the macrodiscectomy group. Mean NASS score for the MLD group was 2.74 vs 2.96 in the conventional group (P = 0.407).
The type of surgery was the significant predictor of improvement in JOA score (P = 0.046) even after adjusting for age, sex, level of lesion and the initial JOA score. MLD as the surgical procedure (P = 0.002) and a lower initial JOA score (P = 0.006) were found significantly contributing to the RM improvement.
The study shows that both MLD and fenestration give comparable results at short-term follow-up. There is statistically significant improvement in MLD with regard to improvement in JOA, VAS and RM scores at 2 years. However, the difference is not large and may not be clinically significant.
PMCID: PMC3849663  PMID: 24063775
Fenestration discectomy; Minimally invasive lumbar discectomy; MLD
7.  An in vivo kinematic comparison of dynamic lumbar stabilization to lumbar discectomy and posterior lumbar fusion using radiostereometric analysis 
Biomechanical studies have shown that dynamic stabilization restores the neutral zone and stabilizes the motion segment. Unfortunately, there are limitations to clinical measurement of lumbar motion segments when using routine radiographs. Radiostereometric analysis is a 3-dimensional technique and can measure the spinal motion segment more accurately than techniques using plain film radiographs. The purpose of this study was measure and compare the range of motion after dynamic stabilization, posterior lumbar fusion (PLF), and lumbar discectomy.
Four patients who underwent lumbar decompression and dynamic stabilization (Dynesys; Zimmer Spine, Inc., Warsaw, Indiana) for treatment of lumbar spondylosis were compared with 4 patients with a similar diagnosis who were treated by PLF and pedicle screw fixation (PLF group) and 8 patients who had undergone lumbar microdiscectomy (discectomy group) for treatment of radiculopathy. During the surgical procedure, 3 to 5 tantalum beads were placed into each of the operative segments. The patients were followed up postoperatively at 1 month, 1 year, and 2 years. At each follow-up time point, segmental motions (flexion, extension, and total sagittal range of motion [SROM]) were measured by radiostereometric analysis.
Flexion, extension, and SROM measured 1.0° ± 0.9°, 1.5° ± 1.3°, and 2.3° ± 1.2°, respectively, in the Dynesys group; 1.0° ± 0.6°, 1.1° ± 0.9°, and 1.5° ± 0.6°, respectively, in the PLF group; and 2.9° ± 2.4°, 2.3° ± 1.5°, and 4.7° ± 2.2°, respectively, in the discectomy group. No significant difference in motion was seen between the Dynesys and PLF groups or between the Dynesys and discectomy groups in extension. Significant differences in motions were seen between the PLF and discectomy groups and between the Dynesys and discectomy groups in flexion (P = .007) and SROM (P = .002). There was no significant change in the measured motions over time.
In this study a significantly lower amount of motion was seen after dynamic stabilization and PLF when compared with discectomy. A future study with a larger cohort is necessary to examine what effect, if any, these motions have on clinical outcomes.
PMCID: PMC4300887
Spine surgery; RSA; Range of motion; Kinematics
8.  Minimum Two-Year Follow-Up of Cases with Recurrent Disc Herniation Treated with Microdiscectomy and Posterior Dynamic Transpedicular Stabilisation 
The objective of this article is to evaluate two-year clinical and radiological follow-up results for patients who were treated with microdiscectomy and posterior dynamic transpedicular stabilisation (PDTS) due to recurrent disc herniation. This article is a prospective clinical study. We conducted microdiscectomy and PDTS (using a cosmic dynamic screw-rod system) in 40 cases (23 males, 17 females) with a diagnosis of recurrent disc herniation. Mean age of included patients was 48.92 ± 12.18 years (range: 21-73 years). Patients were clinically and radiologically evaluated for follow-up for at least two years. Patients’ postoperative clinical results and radiological outcomes were evaluated during the 3rd, 12th, and 24th months after surgery. Forty patients who underwent microdiscectomy and PDTS were followed for a mean of 41 months (range: 24-63 months). Both the Oswestry and VAS scores showed significant improvements two years postoperatively in comparison to preoperative scores (p<0.01). There were no significant differences between any of the three measured radiological parameters (α, LL, IVS) after two years of follow-up (p > 0.05). New recurrent disc herniations were not observed during follow-up in any of the patients. We observed complications in two patients. Performing microdiscectomy and PDTS after recurrent disc herniation can decrease the risk of postoperative segmental instability. This approach reduces the frequency of failed back syndrome with low back pain and sciatica.
PMCID: PMC2864435  PMID: 20448822
Lumbar spine; recurrent disc herniation; decompression; posterior dynamic stabilisation; segmental instability; adjacent level disease.
9.  Posterior Lumbar Interbody Fusion Using a Unilateral Single Cage and a Local Morselized Bone Graft in the Degenerative Lumbar Spine 
Clinics in Orthopedic Surgery  2009;1(4):214-221.
We retrospectively evaluated the clinical and radiological outcomes of posterior lumbar interbody fusion (PLIF) with using a unilateral single cage and a local morselized bone graft.
Fifty three patients who underwent PLIF with a unilateral single cage filled with local morselized bone graft were enrolled in this study. The average follow-up duration was 31.1 months. The clinical outcomes were evaluated with using the visual analogue scale (VAS) at the pre-operative period, at 1 year post-operation and at the last follow-up, the Oswestry Disability Index, the Prolo scale and the Kim & Kim criteria at the last follow-up; the radiological outcomes were evaluated according to the change of bone bridging, the radiolucency, the instablity and the disc height.
For the clinical evaluation, the VAS pain index, the Oswestry Disability Index, the Prolo scale and the Kim & Kim criteria showed excellent outcomes. For the the radiological evaluation, 52 cases showed complete bone union at the last follow-up. Regarding the complications, only 1 patient had cage breakage during follow-up.
PLIF using a unilateral single cage filled with a local morselized bone graft has the advantages of a shorter operation time, less blood loss and a shorter hospital stay, as compared with the PLIF using bilateral cages, for treating degenerative lumbar spine disease. This technique also provides excellent outcomes according to the clinical and radiological evaluation.
PMCID: PMC2784962  PMID: 19956479
Spinal fusion; Posterior lumbar interbody fusion; Unilateral single cage; Local morselized graft
10.  Microdiscectomy compared with standard discectomy: an old problem revisited with new outcome measures within the framework of a spine surgical registry 
European Spine Journal  2009;18(Suppl 3):360-366.
Studies comparing the relative merits of microdiscectomy and standard discectomy report conflicting results, depending on the outcome measure of interest. Most trials are small, and few have employed validated, multidimensional patient-orientated outcome measures, considered essential in outcomes research. In the present study, data were collected prospectively from six surgeons participating in a surgical registry. Inclusion criteria were: lumbar/lumbosacral degenerative disease; discectomy/sequestrectomy without additional fusion/stabilisation; German or English-speaking. Before and 3 and 12 months after surgery, patients completed the Core Outcome Measures Index comprising questions on leg/buttock pain, back pain, back-related function, symptom-specific well-being, general quality-of-life, and social and work disability. At follow-up, they rated overall satisfaction, global outcome, and perceived complications. Compliance with the registry documentation was excellent: 87% for surgeons (surgery forms), 91% for patients (for 12 months follow-up). 261 patients satisfied the inclusion criteria (225 microdiscectomy, 36 standard discectomy). The standard discectomy group had significantly greater blood-loss than the microdiscectomy (P < 0.05). There were no group differences in the proportion of surgical complications or duration of hospital stay (P > 0.05). The groups did not differ in relation to any of the patient-orientated outcomes or individual outcome domains (P > 0.05). Though not equivalent to an RCT, the study included every single eligible patient in our Spine Center and allowed surgeons to use their regular procedure; it hence had extremely high external validity (relevance/generalisability). There was no clinically relevant difference in outcome after lumbar disc excision dependent on the use of the microscope. The decision to use the microscope should rest with the surgeon.
PMCID: PMC2899328  PMID: 19255791
Microdiscectomy; Standard discectomy; Outcome measures; Spine registry
11.  MSU Classification for herniated lumbar discs on MRI: toward developing objective criteria for surgical selection 
European Spine Journal  2010;19(7):1087-1093.
Currently, there are over 300,000 lumbar discectomies performed in the US annually without an objective standard for patient selection. A prospective clinical outcome study of 200 cases with 5-year follow-up was used to develop and validate an MRI-based classification scheme to eliminate as much ambiguity as possible. 100 consecutive lumbar microdiscectomies were performed between 1992 and 1995 based on the criteria for “substantial” herniation on MRI. This series was used to develop the MSU Classification as an objective measure of lumbar disc herniation on MRI to define “substantial”. It simply classifies herniation size as 1-2-3 and location as A-B-C, with inter-examiner reliability of 98%. A second prospective series of 100 discectomies was performed between 2000 and 2002, based on the new criteria, to validate this classification scheme. All patients with size-1 lesions were electively excluded from surgical consideration in our study. The Oswestry Disability Index from both series was better than most published outcome norms for lumbar microdiscectomy. The two series reported 96 and 90% good to excellent outcomes, respectively, at 1 year, and 84 and 80% at 5 years. The most frequent types of herniation selected for surgery in each series were types 2-B and 2-AB, suggesting the combined importance of both size and location. The MSU Classification is a simple and reliable method to objectively measure herniated lumbar disc. When used in correlation with appropriate clinical findings, the MSU Classification can provide objective criteria for surgery that may lead to a higher percentage of good to excellent outcomes.
PMCID: PMC2900017  PMID: 20084410
MRI; Discectomy; Classification; Substantial herniated disc; Low back pain
12.  Does minimally invasive lumbar disc surgery result in less muscle injury than conventional surgery? A randomized controlled trial 
European Spine Journal  2010;20(1):51-57.
The concept of minimally invasive lumbar disc surgery comprises reduced muscle injury. The aim of this study was to evaluate creatine phosphokinase (CPK) in serum and the cross-sectional area (CSA) of the multifidus muscle on magnetic resonance imaging as indicators of muscle injury. We present the results of a double-blind randomized trial on patients with lumbar disc herniation, in which tubular discectomy and conventional microdiscectomy were compared. In 216 patients, CPK was measured before surgery and at day 1 after surgery. In 140 patients, the CSA of the multifidus muscle was measured at the affected disc level before surgery and at 1 year after surgery. The ratios (i.e. post surgery/pre surgery) of CPK and CSA were used as outcome measures. The multifidus atrophy was classified into three grades ranging from 0 (normal) to 3 (severe atrophy), and the difference between post and pre surgery was used as an outcome. Patients’ low-back pain scores on the visual analogue scale (VAS) were documented before surgery and at various moments during follow-up. Tubular discectomy compared with conventional microdiscectomy resulted in a nonsignificant difference in CPK ratio, although the CSA ratio was significantly lower in tubular discectomy. At 1 year, there was no difference in atrophy grade between both groups nor in the percentage of patients showing an increased atrophy grade (14% tubular vs. 18% conventional). The postoperative low-back pain scores on the VAS improved in both groups, although the 1-year between-group mean difference of improvement was 3.5 mm (95% CI; 1.4–5.7 mm) in favour of conventional microdiscectomy. In conclusion, tubular discectomy compared with conventional microdiscectomy did not result in reduced muscle injury. Postoperative evaluation of CPK and the multifidus muscle showed similar results in both groups, although patients who underwent tubular discectomy reported more low-back pain during the first year after surgery.
PMCID: PMC3036021  PMID: 20556439
Creatine phosphokinase; Muscle injury; Atrophy; Microdiscectomy; Herniated disc; Low-back pain
13.  Learning curve of full-endoscopic lumbar discectomy 
European Spine Journal  2012;22(4):727-733.
To report the learning curve of full-endoscopic lumbar discectomy for a surgeon naive to endoscopic surgery but trained in open microdiscectomy.
From July 2006 to July 2009, 57 patients underwent full-endoscopic lumbar discectomy and 66 underwent open microdiscectomy. The clinical results were evaluated with a visual analog scale (VAS) and the Oswestry Disability Index (ODI). Spearman’s coefficient of rank correlation (rho) was used to assess the learning curves for the transforaminal and interlaminar procedures of full-endoscopic lumbar discectomy.
After full-endoscopic lumbar discectomy, the VAS and ODI results of the patients followed up were comparable with those of open microdiscectomy. A steep learning curve was observed for the transforaminal procedure, but not the interlaminar procedure.
The learning curve of the transforaminal approach was steep and easy to learn, while the learning curve of the interlaminar approach was flat and hard to master.
PMCID: PMC3631049  PMID: 23076645
Learning curve; Disc herniation; Endoscopic lumbar discectomy; Transforaminal procedure; Interlaminar procedure
14.  Stabilising effect of dynamic interspinous spacers in degenerative low-grade lumbar instability 
International Orthopaedics  2010;35(3):395-400.
The aim of the study was to investigate the stabilising effect of dynamic interspinous spacers (IS) in combination with interlaminar decompression in degenerative low-grade lumbar instability with lumbar spinal stenosis and to compare its clinical effect to patients with lumbar spinal stenosis in stable segments treated by interlaminar decompression only. Fifty consecutive patients with a minimum age of 60 years were scheduled for interlaminar decompression for clinically and radiologically confirmed lumbar spinal stenosis. Twenty-two of these patients (group DS) with concomitant degenerative low-grade lumbar instability up to 5 mm translational slip were treated by interlaminar decompression and additional dynamic IS implantation. The control group (D) with lumbar spinal stenosis in stable segments included 28 patients and underwent only interlaminar decompression. The mean follow-up was 46 months in group D and 44 months in group DS. A visual analogue scale (VAS), Oswestry Disability Index (ODI) and walking distance were evaluated pre- and postoperatively. The segmental instability was evaluated in flexion-extension X-rays. The implantation of an IS significantly reduced the lumbar instability on flexion-extension X-rays. At the time of follow-up walking distance, VAS and ODI showed a significant improvement in both groups, but no statistical significance between groups D and DS. Four patients each in groups D and DS had revision surgery during the period of evaluation. The stabilising effect of dynamic IS in combination with interlaminar decompression offers an opportunity for an effective treatment for degenerative low-grade lumbar instability with lumbar spinal stenosis.
PMCID: PMC3047654  PMID: 20419452
15.  SPORT: Do outcomes vary across centers for surgery for lumbar disc herniation? 
Neurosurgery  2012;71(4):833-842.
Lumbar discectomy is the most common procedure performed in spine surgery. Different centers performing this procedure may have different outcomes.
To determine whether the choice of academic spine center in which surgery is performed affects outcome after lumbar discectomy.
Spine Patient Outcomes Research Trial (SPORT) cohort participants with a confirmed diagnosis of intervertebral disc herniation (IDH) undergoing standard first-time open discectomy were followed from baseline at 6 weeks, and 3, 6, 12 months and yearly thereafter, at 13 spine clinics in 11 US states. Patient data were retrospectively reviewed. As of August 2009, the mean (SD) follow-up among all analyzed IDH patients was 41.3 (14.6) months. The median (range) follow-up time among all analyzed IDH patients was 47.4 (1.3, 95.3) months. Enrollment began in March 2000 and ended in November 2004.
792 patients underwent first-time lumbar discectomy. Significant differences were found amongst centers with regard to patient age and race, and in baseline levels of disability and treatment preferences. There were no significant differences among the study centers in other patient characteristics (e.g., sex, body mass index, the prevalence of smoking, diabetes or hypertension), or disease characteristics (herniation level or type). Some short-term outcomes varied significantly among centers, including operative duration and blood loss, the incidence of durotomy and the length of hospital stay. Unadjusted reoperation rates also varied across centers. There were no differences among the various centers in incidence of nerve root injury, post-operative mortality, SF-36 scores of body pain or physical function, or Oswestry Disability Index at 4 years.
Although mean operative blood loss, risk of durotomy and length of hospital stay vary across academic centers performing lumbar discectomy, there appears to be no difference in long-term functional outcomes. The role of different reoperation rates in producing similar outcomes remains unclear.
PMCID: PMC4011394  PMID: 22791040
Clinical outcomes; Lumbar spine; Surgical complications
16.  Effect of 10-week core stabilization exercise training and detraining on pain-related outcomes in patients with clinical lumbar instability 
Background and aims
Clinical lumbar instability causes pain and socioeconomic suffering; however, an appropriate treatment for this condition is unknown. This article examines the effect of a 10 week core stabilization exercise (CSE) program and 3 month follow-up on pain-related outcomes in patients with clinical lumbar instability.
Forty-two participants with clinical lumbar instability of at least 3 months in duration were randomly allocated either to 10 weekly treatments with CSE or to a conventional group (CG) receiving trunk stretching exercises and hot pack. Pain-related outcomes including pain intensity during instability catch sign, functional disability, patient satisfaction, and health-related quality of life were measured at 10 weeks of intervention and 1 and 3 months after the last intervention session (follow-up); trunk muscle activation patterns measured by surface electromyography were measured at 10 weeks.
CSE showed significantly greater reductions in all pain-related outcomes after 10 weeks and over the course of 3 month follow-up periods than those seen in the CG (P<0.01). Furthermore, CSE enhanced deep abdominal muscle activation better than in the CG (P<0.001), whereas the CG had deterioration of deep back muscle activation compared with the CSE group (P<0.01). For within-group comparison, CSE provided significant improvements in all pain-related outcomes over follow-up (P<0.01), whereas the CG demonstrated reduction in pain intensity during instability catch sign only at 10 weeks (P<0.01). In addition, CSE showed an improvement in deep abdominal muscle activation (P<0.01), whereas the CG revealed the deterioration of deep abdominal and back muscle activations (P<0.05).
Ten week CSE provides greater training and retention effects on pain-related outcomes and induced activation of deep abdominal muscles in patients with clinical lumbar instability compared with conventional treatment.
PMCID: PMC3875242  PMID: 24399870
clinical lumbar instability; quality of life; detraining effect; trunk muscle activation; core stabilization exercise
17.  Higher preoperative Oswestry Disability Index is associated with better surgical outcome in upper lumbar disc herniations 
European Spine Journal  2007;17(1):117-121.
To evaluate the surgical outcome in terms of functional and subjective recovery, patients who needed discectomies at L1–L2, L2–L3 and L3–L4 levels were compared with an age and sex-matched group of patients who required L4–L5 and L5–S1 discectomies. We prospectively enrolled 50 consecutive patients, referred to our center, who had L1–L2, L2–L3 and L3–L4 herniations and required surgical intervention. Likewise, a comparative group of 50 consecutive patients with herniations at L4–L5 and L5–S1 were selected. All 100 patients were treated and followed for a 1 year period. Physical examination findings as well as Oswestry Disability Questionnaire before surgery were recorded. After 1 year, patients were requested to fill the same questionnaire. Significant decline in the Oswestry Disability Index (ODI) scores was considered to be a measure of functional improvement and recovery. The mean age of patients with upper lumbar disc herniation (L1–L2, L2–L3, L3–L4) was 45.7 years and patients with lower lumbar disc herniation (L4–L5, L5–S1) had a mean age of 41.2 years. There was no statistically significant difference in age between the two groups. The preoperative Oswestry Disability (ODI) Index score had a statistically significant impact on ODI score improvement after surgery in both lower and upper lumbar disc groups. All 100 patients with either lower or upper lumbar disc herniation had statistically significant ODI change after surgical intervention (P < 0.0001 for both groups). However, patients with upper disc herniations and moderate preoperative disability (ODI of 21–40%) did not show significant improvement, while patients with ODI greater than 40% had significant reduction (P = 0.018). Surprisingly, as many as 25% of the former had even an increase in ODI scores after surgery. Gender was also a conspicuous factor in determining the surgical outcome of patients with upper lumbar disc herniation, and male patients had more reduction in ODI score than female patients (P = 0.007). Since the functional recovery in patients with herniated lumbar disc, especially upper lumbar herniation, is influenced by preoperative ODI scores, the use of ODI or any other standard pain assessment tool is a sensible consideration as an inherent investigative method to preclude unfavorable surgical outcome.
PMCID: PMC2365528  PMID: 17972115
Upper lumbar disc; Oswestry Disability Index; Surgical outcome
18.  Clinical results of XMR-assisted percutaneous transforaminal endoscopic lumbar discectomy 
Although percutaneous endoscopic lumbar discectomy (PELD) has shown favorable outcomes in the majority of lumbar discectomy cases, there were also some failures. The most common cause of failure is the incomplete removal of disc fragments. The skin entry point for the guide-needle trajectory and the optimal placement of the working sleeve are largely blind, which might lead to the inadequate removal of disc fragments. The objective of this study was to present our early experiences with image-guided PELD using a specially designed fluoroscope with magnetic resonance imaging-equipped operative suite (XMR) for the treatment of lumbar disc herniation.
This prospective study included 89 patients who had undergone PELD via the transforaminal approach using an XMR protocol. Pre- and postoperative examinations (at 12 weeks) included a detailed clinical history, visual analogue scale (VAS), Oswestry disability index (ODI), and radiological workups. The results were categorized as excellent, good, fair, and poor according to MacNab's criteria. At the final follow-up, the minimum follow-up time for the subjects was 2 years. The need for revision surgeries and postoperative complications were noted on follow-up.
Postoperative mean ODI decreased from 67.4% to 5.61%. Mean VAS score for back and leg pain improved significantly from 4 to 2.3 and from 7.99 to 1.04, respectively. Four (4.49%) patients underwent a second-stage PELD after intraoperative XMR had shown remnant fragments after the first stage. As per MacNab's criteria, 76 patients (85.4%) showed excellent, 8 (8.89%) good, 3 (3.37%) fair, and 2 (2.25) poor results. Four (4.49%) patients had remnant disc fragments on XMR, which were removed during the same procedure. All of these patients had either highly migrated or sequestrated disc fragments preoperatively. Four (4.49%) other patients needed a second, open surgery due to symptomatic postoperative hematoma (n = 2) and recurrent disc herniation (n = 2).
This prospective analysis indicates that XMR-assisted PELD provides a precise skin entry point. It also confirms that decompression occurs intraoperatively, which negates the need for a separate surgery and thus increases the success rate of PELD, particularly in highly migrated or sequestrated discs. However, further extensive experience is required to confirm the advantages and feasibility of PELD in terms of cost effectiveness.
PMCID: PMC3668223  PMID: 23705685
Percutaneous endoscopic lumbar discectomy; Incomplete disc removal; XMR-guided procedure; High success rate
19.  Frequency and clinical meaning of long-term degenerative changes after lumbar discectomy visualized on imaging tests 
European Spine Journal  2009;19(1):136-143.
The aim of this retrospective controlled study was to evaluate radiographic degeneration in the lumbar spine of patients who had undergone lumbar discectomy minimum 21 years earlier and its clinical meaning. Indeed, no previous investigation on degenerative changes occurring after lumbar discectomy with a comparable long follow-up has been published. The study participants consisted of 50 patients who had undergone discectomy for lumbar disc herniation. The mean length of follow-up was 25.3 ± 3.0 years. Patients were assessed by Short Form-36 Health Survey (SF-36), Oswestry Disability Index, and a study-specific questionnaire. Radiographic views of the lumbar spine were obtained from all patients and compared to those of 50 asymptomatic controls. A five-step published classification was used to assess the increasing severity of radiographic changes. CT or MRI scans were also available for 27 patients who had undergone discectomy. Moderate to severe radiographic changes were present in 45 patients (90%) and 34 controls (68%), respectively (P = 0.013). The most prevalent MRI/CT changes were loss of disc height (89%), facet joint arthritis (89%), and endplate changes (57%). Thirty-two of 33 subjects (97%) reporting pain during the last 12 months had significant degeneration on their radiographs, and the frequency of changes was higher with respect to subjects without pain (P = 0.040). In conclusion, standard lumbar discectomy frequently leads to long-term degenerative changes on imaging tests. The presence of moderate to severe degeneration is associated with self-reported pain.
PMCID: PMC2899737  PMID: 19894068
Discectomy; Low back pain; Long term follow-up; Lumbar spine; Radiography; Surgery
20.  Recurrence Rate after Herniotomy only versus Discectomy in Lumbar Disc Herniation 
Korean Journal of Spine  2013;10(4):227-231.
Lumbar disc herniation (LDH) recurrence necessitating reoperation can pose problems following spinal surgery, with an overall reported incidence of approximately (3-13%). The purpose of this study is to identify the rate of recurrent disc herniation, to discuss the radiologic indications for herniotomy and to analyze clinical outcomes compared with conventional discectomy.
This study is a retrospective case control study. The authors retrospectively reviewed 114 patients who underwent herniotomy & conventional discectomy by a single surgeon for single-level LDH between June 2009 and May 2012. Herniotomy group was 57 patients and conventional discectomy group was 57 patients that were selected from 631 patients using stratified randomization. Evaluation for LDH recurrence included detailed medical chart and radiologic review and telephone interview. Postoperative VAS and the Korean version of ODI were examined one week after surgery. Clinical outcome was investigated according to Odom's criteria from three months to three years.
Of the 114 patients for whom the authors were able to definitively assess symptomatic recurrence status, four patients (7%) experienced LDH recurrence following single-level herniotomy and three patients (5.2%) conventional discectomy. There were no differences in the VAS and Korean version of ODI between herniotomy group and conventional discectomy group. The herniotomy group had better results than the conventional discectomy group in clinical outcome from three months to three years, but the difference was not significant.
There were no significant differences in clinical outcome between herniotomy and conventional discectomy. Recurrence rates following herniotomy for LDH compare favorably with those in patients who have undergone conventional discectomy, lending further support for its effectiveness in treating herniotomy.
PMCID: PMC4040647  PMID: 24891853
Lumbar Vertebrae; Herniated Disc; Diskectomy; Recurrence
21.  Mid-range outcomes in 64 consecutive cases of multilevel fusion for degenerative diseases of the lumbar spine 
Orthopedic Reviews  2010;2(1):e3.
In the treatment of multilevel degenerative disorders of the lumbar spine, spondylodesis plays a controversial role. Most patients can be treated conservatively with success. Multilevel lumbar fusion with instrumentation is associated with severe complications like failed back surgery syndrome, implant failure, and adjacent segment disease (ASD). This retrospective study examines the records of 70 elderly patients with degenerative changes or instability of the lumbar spine treated between 2002 and 2007 with spondylodesis of more than two segments. Sixty-four patients were included; 5 patients had died and one patient was lost to follow-up. We evaluated complications, clinical/radiological outcomes, and success of fusion. Flexion-extension and standing X-rays in two planes, MRI, and/or CT scans were obtained pre-operatively. Patients were assessed clinically using the Oswestry disability index (ODI) and a Visual Analogue Scale (VAS). Surgery performed was dorsolateral fusion (46.9%) or dorsal fusion with anterior lumbar interbody fusion (ALIF; 53.1%). Additional decompression was carried out in 37.5% of patients. Mean follow-up was 29.4±5.4 months. Average patient age was 64.7±4.3 years. Clinical outcomes were not satisfactory for all patients. VAS scores improved from 8.6±1.3 to 5.6±3.0 pre- to post-operatively, without statistical significance. ODI was also not significantly improved (56.1±22.3 pre- and 45.1±26.4 post-operatively). Successful fusion, defined as adequate bone mass with trabeculation at the facets and transverse processes or in the intervertebral segments, did not correlate with good clinical outcomes. Thirty-five of 64 patients (54%) showed signs of pedicle screw loosening, especially of the screws at S1. However, only 7 of these 35 (20%) complained of corresponding back pain. Revision surgery was required in 24 of 64 patients (38%). Of these, indications were adjacent segment disease (16 cases), pedicle screw loosening (7 cases), and infection (one case). At follow-up of 29.4 months, patients with radiographic ASD had worse ODI scores than patients without (54.7 vs. 36.6; P<0.001). Multilevel fusion for degenerative disease still has a high rate of complications, up to 50%. The problem of adjacent segment disease after fusion surgery has not yet been solved. This study underscores the need for strict indication guidelines to perform lumbar spine fusion of more than two levels.
PMCID: PMC3143945  PMID: 21808698
lumbar spine; multilevel fusion; complication; degenerative disease; adjacent segment disease; implant loosening; topping off.
22.  Lumbar microdiscectomy and lumbar decompression improve functional outcomes and depression scores 
Study design: Retrospective review.
Introduction: Lumbar radiculopathy and claudicant leg pain are common degenerative spinal conditions often treated by elective microdiscectomy or decompression. Published outcome data for these procedures have focused on improvement in pain scores, and not on grounded functional outcome or depression scores.1,2,3 Moreover, depression is considered by many surgeons to be a red flag for poor outcome for surgical treatment. We asked what effect lumbar microdiscectomy and laminectomy procedures had on functional outcome and depression scores in our clinical population.
Methods: Beginning in January 2010, the following outcome data were prospectively gathered before and after surgery from all patients at the Cleveland Clinic undergoing either lumbar microdiscectomy or lumbar decompression: EQ-5D (EuroQOL, quality-of-life measure), PHQ-9 (measure of depressive symptoms), PDQ (pain disability questionnaire), and Rankin scores (disability or dependence in daily activities).
Results: The mean EuroQOL scores improved by 35% (from 0.4–0.75 of a maximum of 1.0) for both microdiscectomy and lumbar laminectomies. The mean PHQ-9 scores (measure of depressive symptoms) significantly improved for most patients undergoing either procedure. In line with previously published reports, we also found improvement in Rankin scores and Pain Disability Questionnaire scores.
Conclusions: Our outcome data indicate that microdiscectomy and lumbar decompression not only reduce disability and pain but also improve depressive symptoms and overall quality of life for patients. These findings support operative treatment of lumbar radiculopathy and neurogenic claudication including treatment performed in the depressed population.
PMCID: PMC3592778  PMID: 23526915
23.  Long-term outcome after implantation of prosthetic disc nucleus device (PDN) in lumbar disc disease 
Hippokratia  2010;14(3):176-184.
Background: The prosthetic disc nucleus (PDN) device offers an adjunct treatment for patients with degenerative disc disease and herniation, who necessitate surgical intervention, avoiding total-disc replacement or fusion. This prospective, clinical study aimed to gauge the long-term effectiveness of microdiscectomy followed by PDN implantation in relieving pain and improving functional status in patients with symptomatic degenerative lumbar disc disease and herniation.
Methods: Ten patients with a) at least 6 months low back pain and/or sciatica resistant to conservative treatment and b) radiologically documented degenerative lumbar disc disease and herniation have been selected. Follow-up at 6 weeks, 3, 12, 48, and 96 months postoperatively included physical examination, radiological investigation (plain and dynamic radiographs and magnetic resonance imaging), and self-completion of outcome scales (visual analogue, Oswestry, and Prolo functional status). Short Form-36 version 2 Health Survey patient profile at 96 months completed the image of health related quality of life.
Results: Patients' mean follow-up was 100.6 months. Significant improvements in Oswestry, Prolo, and VAS scores were documented (p: 0.004 in all scales at 48 months). Generic health status was rated within the average lumbar disease population (46.36.8 for physical component summary and 45.29.6 for mental component summary). Lumbar spine range of motion (20.211.8 at 96 months) was restricted in relation to normal, but maintained considerable mobility. Treated disc height increased postoperatively (p:0.002) and its maintenance could also be documented in all cases. Disc height at the level above did not show any significant modification. All postoperative MRI showed a non-clinically significant high signal of end-plate on T2 sequences. Clinically relevant complications included one case of pulmonary thrombosis and one case of device extrusion, which was subsequently explanted.
Conclusions: After implantation, most patients continue to enjoy significant pain relief, a considerable amount of mobility is conserved and the disease specific functional outcome is excellent and remains for long, although it could not be supported that the generic health related quality of life is that of the general population.
PMCID: PMC2943355  PMID: 20981166
artificial disc; degenerative disc disease; lumbar disc herniation; prosthetic disc nucleus
24.  Comparison of the early results of transforaminal lumbar interbody fusion and posterior lumbar interbody fusion in symptomatic lumbar instability 
Indian Journal of Orthopaedics  2013;47(3):255-263.
Transforaminal lumbar interbody fusion (TLIF) has been preferred to posterior lumbar interbody fusion (PLIF) for different spinal disorders but there had been no study comparing their outcome in lumbar instability. A comparative retrospective analysis of the early results of TLIF and PLIF in symptomatic lumbar instability was conducted between 2005 and 2011.
Materials and Methods:
Review of the records of 102 operated cases of lumbar instability with minimum 1 year followup was done. A total of 52 cases (11 men and 41 women, mean age 46 years SD 05.88, range 40-59 years) underwent PLIF and 50 cases (14 men and 36 women, mean age 49 years SD 06.88, range 40-59 years) underwent TLIF. The surgical time, duration of hospital stay, intraoperative blood loss were compared. Self-evaluated low back pain and leg pain status (using Visual Analog Score), disability outcome (using Oswestry disability questionnaire) was analyzed. Radiological structural restoration (e.g., disc height, foraminal height, lordotic angle, and slip reduction), stability (using Posner criteria), fusion (using Hackenberg criteria), and overall functional outcome (using MacNab's criteria) were compared.
Pain, disability, neurology, and overall functional status were significantly improved in both groups but PLIF required more operative time and caused more blood loss. Postoperative hospital stay, structural restoration, stability, and fusion had no significant difference but neural complications were relatively more with PLIF.
Both methods were effective in relieving symptoms, achieving structural restoration, stability, and fusion, but TLIF had been associated with shorter operative time, less blood loss, and lesser complication rates for which it can be preferred for symptomatic lumbar instability.
PMCID: PMC3687902  PMID: 23798756
Lumbar instability; posterior lumbar interbody fusion; transforaminal lumbar interbody fusion
25.  Adjacent segment degeneration after single-segment PLIF: the risk factor for degeneration and its impact on clinical outcomes 
European Spine Journal  2011;20(11):1946-1950.
To investigate: (1) the risk factors for radiologic cranial adjacent segment degeneration (ASD) after single-segment PLIF at the same level, and (2) the impact of the ASD on the clinical outcomes.
From October 2004 to May 2009, 109 patients who underwent PLIF for degenerative instability at L4/5 and have more than 2 years follow-up were studied retrospectively. We measured the preoperative bone mineral density (BMD), lumbar lordosis, the lumbosacral joint angle, the lumbar inclination, the height and the dynamic angulation of the intervertebral space at the fused segments and the upper adjacent segment, the sliding displacement between L3 and L4. Clinical outcomes were evaluated using the Japanese Orthopedic Association (JOA) score and the Oswestry Disability Index (ODI). Patients were divided into two groups according to the progression of L3–L4 degeneration: Group A without progression of L3–L4 degeneration, Group B with progression of L3–L4 degeneration. Clinical outcomes and radiologic measurement index between the two groups were compared, and the risk factors for progression of L3–L4 degeneration were analyzed. The correlation between clinical outcomes and progression of L3–L4 degeneration were also investigated.
There were 11 patients (22%) classified into Group A. No significant difference was found between the two groups in terms of the lordosis angle at L1 and S1, the laminar inclination at L3, the pre-existing L3–L4 disk degeneration, the lordosis angle of L4–L5, the lumbosacral joint angle and preoperative BMD (P > 0.05). Significant differences were found between the two groups in age. No significant difference was found between the two groups in the ODI and the JOA score at the final follow-up (P > 0.05).
Radiologic degeneration of the cranial adjacent segment after single-segment PLIF did not significantly correlate with clinical outcomes. Age was a risk factor for radiologic degeneration, however, there was no significant correlation between degeneration and preoperative radiologic factors and bone mineral density (BMD).
PMCID: PMC3207340  PMID: 21720728
Lumbar fusion; Adjacent segment degeneration; Risk factor; Clinical outcome

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