Long-term follow-up of standard microdiscectomy versus minimal access surgery for lumbar disc herniations

Transforaminal Endoscopic Lumbar Diskectomy versus Open Microdiskectomy for Symptomatic Lumbar Disk Herniation: A Comparative Cohort Study on Costs and Long-Term Outcomes

BACKGROUND

 Transforaminal endoscopic lumbar diskectomy (TELD) is considered an effective treatment for lumbar disk herniation (LDH). There is a paucity of studies comparing in detail the costs and long-term clinical outcomes of TELD and open microdiskectomy (MD), especially in developing countries. Thus, we sought to provide a multidimensional insight into this matter by comparing the direct costs and long-term outcomes of TELD with those of MD.

METHODS

 The electronic health records of 434 patients with LDH who underwent either TELD or MD were collected from February 2011 to October 2014. Within a 7-year follow-up period, 412 patients, comprising 203 patients treated with TELD and 209 patients treated with MD, were fully evaluated. Patient characteristics, operative time, intraoperative blood loss (IBL), postoperative hospital stay, time to return to work (RTW), perioperative complications, and direct costs were collected. Clinical outcomes were assessed using the Visual Analog Scale (VAS), Oswestry Disability Index (ODI), and modified MacNab criteria.

RESULTS

 The postoperative ODI and VAS scores improved significantly in both groups (p < 0.001). In accordance with the modified MacNab criteria, the rate of excellent and good outcomes was 88.67 and 88.03% in the TELD and MD groups, respectively. There were no significant differences between the groups in the clinical outcomes and perioperative complications. However, IBL, hospital stay, and RTW were significantly reduced in the TELD group (p < 0.05). Twenty-one cases in the TELD group and nine in the MD group underwent reoperation due to recurrence (p < 0.05). Total inpatient cost per patient was $1,596 in the TELD group and $1,990 in the MD group (p < 0.05).

CONCLUSION

 TELD for the treatment of symptomatic LDH could be an affordable strategy, providing certain advantages of minimally invasive procedures such as shorter hospital stay and earlier recovery along with comparable clinical outcomes to the conventional surgical method.

Comparison of outcomes between tubular microdiscectomy and conventional microdiscectomy for lumbar disc herniation: a systematic review and meta-analysis of randomized controlled trials

PURPOSE

The clinical outcomes of using a tubular microdiscectomy for lumbar disc herniation were evaluated by comparison with conventional microdiscectomy.

METHODS

All of the comparative studies published in the PubMed, Cochrane Library, Medline, Web of Science, and EMBASE databases as of 1 May 2023 were included. All outcomes were analysed using Review Manager 5.4.

RESULTS

This meta-analysis included four randomized controlled studies with a total of 523 patients. The results showed that using tubular microdiscectomy for lumbar disc herniation was more effective than conventional microdiscectomy in improving the Oswestry Disability Index (P < 0.05). However, there were no significant differences in operating time, intraoperative blood loss, hospital stay, Visual Analogue Scale, reoperation rate, postoperative recurrence rate, dural tear incidence, and complications rate (all P > 0.05) between the tubular microdiscectomy and conventional microdiscectomy groups.

CONCLUSIONS

Based on our meta-analysis, it was found that the tubular microdiscectomy group had better outcomes than the conventional microdiscectomy group in terms of Oswestry Disability Index. However, there were no significant differences between the two groups in terms of operating time, intraoperative blood loss, hospital stay, Visual Analogue Scale, reoperation rate, postoperative recurrence rate, dural tear incidence, and complications rate. Current research suggests that tubular microdiscectomy can achieve clinical results similar to those of conventional microdiscectomy. PROSPERO registration number is: CRD42023407995.

Endoscopic discectomy of the herniated intervertebral disc and changes in quality-of-life EQ-5D-5L analysis

Herniated lumbar discs are a common cause of low back pain, which can negatively impact the quality of life of working-age individuals. This study aimed to evaluate changes in the quality of life in patients with sciatica who underwent endoscopic discectomy, a minimally invasive surgical procedure. The study (ClinicalTrials.gov NCT02742311) included 470 patients who underwent transforaminal, interlaminar, or translaminar endoscopic discectomy. Quality of life and pain perception were evaluated by comparing statistically weighted values of EQ-5D-5L, EQ-VAS, Oswestry disability index, and numerical pain scales for lower limb and back pain before and 12 months after the endoscopic procedure. After the procedure, there was a significant improvement in the reduction of back and lower limb pain, as well as in all monitored questionnaires (P < .001), which persisted 12 months after the endoscopy. All evaluated dimensions of the EQ-5D-5L questionnaire indicated a significant improvement in the assessed quality of life (P < .001). The study showed that percutaneous endoscopic lumbar discectomy is an effective pain-treating intervention that can improve the quality of life. There was no observed difference in the percentage of complications or re-herniations when comparing the transforaminal and interlaminar, approaches.

Percutaneous Transforaminal Endoscopic Diskectomy for Lumbar Disk Herniation: Young (Age <60 years) versus Older (Age ≥60 years) Patients

BACKGROUND

 We compare the differences in the efficacy of percutaneous transforaminal endoscopic diskectomy (PTED) between the younger (age <60 years) and older (age ≥60 years) patients with lumbar disk herniation (LDH).

METHODS

 From December 2016 to December 2017, 128 patients with symptomatic LDH underwent PTED and were followed up. Forty-four 60 years old and above, including 19 males and 25 females with an average age of 68.7 (61-82) years, were classified as the elderly age group. Eighty-four patients younger than 60 years were classified as the young age group, which included 48 males and 36 females with an average age of 44.7 (16-58) years. The visual analog scale (VAS) scores, Japanese Orthopaedic Association (JOA) scores, and satisfaction rates of the two groups before and after surgery were compared.

RESULTS

 The operation was completed successfully in both groups. The average follow-up times of the elderly and young age groups were 18.47 ± 2.62 (12-23) and 17.90 ± 3.27 (12-23) months, respectively. One patient in the young age group had recurrence 7 months after surgery, and the symptoms were relieved after PTED was performed again. Two patients with nerve root injury after surgery in the young age group completely recovered after 2 months of conservative treatment. There were no significant surgical complications in the elderly age group. There was no significant difference in postoperative VAS, JOA, and MacNab scores between the two groups. The MacNab scores in the elderly age group were excellent for 28 patients, good for 10 patients, and fair for 6 patients; the satisfaction rate was 86.3%. In the young age group, scores were excellent for 63 patients, good for 14 patients, fair for 5 patients, and poor for 2 patients; the satisfaction rate was 91.7%.

CONCLUSION

 The clinical effectiveness of PTED for treatment of LDH in both elderly and young patients is satisfactory. Age is not a predictor of poor outcomes of PTED.

Minimally invasive microsurgical treatment of spinal dural arteriovenous fistula: how I do it

BACKGROUND

Spinal dural arteriovenous fistula (d-AVF) is the most common spinal vascular malformations. Management includes endovascular embolization, and/or surgical obliteration of the shunt.

METHOD

Applied to spinal d-AVF, mini-invasive surgical (MIS) obliteration is described as a mini-open approach using Mast Quadrant™ system. Important anatomical landmarks are reviewed. Indications, advantages, and limitations are discussed, and a step-by-step description of the procedure is presented.

CONCLUSION

MIS is a good solution to treat d-AVF with a good outcome.

Retrospective Analysis of Reoperation Rate After Standard Lumbar Discectomy and Microdiscectomy - Single Center Experience

Discectomy is a surgical procedure in the treatment of lumbar disc herniation (LDH) if sciatica or neurological deficits occur and still persist after a course of conservative therapy. Standard discectomy (SD) and microdiscectomy (MD) are still equal in curent clinical practice. Many retrospective and prospective studies have shown that there is no clinically significant difference in the functional outcome after two treatment modalities.

The aim of our study was to determine whether there are differences in the incidence of reoperation after performing SD and MD.

The research included 545 patients with average period of postoperative follow-up of approximately 5.75 years. Standard discectomy was performed in 393 patients (72.11%), and micro-discectomy in 152 (27.8%) patients. The total number of reoperated patients was 37/545, or 6.78%. In the SD group, the number of reoperated patients was 33/393 (8.39%) and in the MD group 4/152 or 2.63%. Statistically significant difference (p <0.05) was recorded in favor of the MD group.

Although it has been proven that both SD and MD give good endpoints of treatment and similar functional recovery, the advantage is given to microdiscectomy due to statistically significantly lower rates of recurrent herniation. This result is attributed to better visualization of neural structures and pathological substrates, as well as their mutual relationship.

Minimum Seven-Year Follow-Up Outcomes of Percutaneous Endoscopic Lumbar Discectomy for Lumbar Degenerative Disease

Purpose

To investigate the long-term (> 7 years) clinical outcomes of percutaneous endoscopic lumbar discectomy for lumbar degenerative disease to address postoperative problems including postoperative dysesthesia (POD), residual back pain and segmental instability.

Methods

Inclusion and exclusion criteria were established. All patients who met the above criteria were treated by PELD using the transforaminal approach. Limited discectomy was performed to preserve the disc material in the intervertebral space as much as possible. The Oswestry Disability Index (ODI), Japanese Orthopaedic Association (JOA) score, visual analog scale (VAS) score for back pain (VAS-B) and leg pain (VAS-L) and Modified MacNab’s criterion were used for clinical evaluation. Radiographic parameters including height of intervertebral disc and segmental instability were also evaluated.

Results

Forty-two patients (24 men and 18 women) who met our inclusion and exclusion criteria were included in our study. The average follow-up period was 95.71±5.63 months (ranging from 87 to 105 months). There were no neurological complications associated with the operation. POD was found in 14.29% of patients, while only 2 patients (4.76%) complained of mild dysesthesia at final follow-up. Two patients (4.76%) required revision surgery during the follow-up period. The final follow-up ODI, JOA score, VAS-B and VAS-L were significantly better than preoperative values. The average disc-height ratio was 84.52±5.66% of the preoperative disc height. No instability at the operation level was noted at final follow-up.

Conclusion

Our study showed that PELD using the transforaminal approach can provide favorable results after a long-term follow-up period. POD is a common complication at initial prognosis. Limited discectomy can preserve the disc height well and minimize the risk of residual back pain.

A matched comparison of outcomes between percutaneous endoscopic lumbar discectomy and open lumbar microdiscectomy for the treatment of lumbar disc herniation: a 2-year retrospective cohort study

BACKGROUND CONTEXT

Although open lumbar microdiscectomy (OLMD) is considered to be the gold standard method for discectomy, recent progress in endoscopic spinal surgery has increased the popularity of percutaneous endoscopic lumbar discectomy (PELD) for this indication. However, one of the main drawbacks of PELD is incomplete decompression, especially at the start of the surgeon's learning curve. The functional outcomes of PELD and OLMD in patients matched for age, hernia level, and hernia location have not previously been compared.

PURPOSE

To compare OLMD with PELD in terms of the clinical outcome and the time to recovery.

STUDY DESIGN

Retrospective, matched cohort study.

PATIENT SAMPLE

Data of all patients who underwent elective spinal surgery between January 2015 and June 2017 were extracted from the local database.

OUTCOME MEASURES

Clinical outcomes were assessed using a 0-to-10 visual analogue scale (VAS) for lower back pain (LBP) and leg pain were scored before surgery and at postoperative day 1 and at each follow-up visit (3, 12, and 24 months), the Oswestry Disability Index (ODI: 0%-100%), the length of hospital stay, time to resumption of work, recurrence of Lumbar disc herniation, procedure failures, and complications.

METHODS

The participants were matched for age, disc level, and location of the herniated disk (central and paracentral vs. far-lateral). The participants' mean±standard deviation age was 47.09±12.55 (range: 28-70). We compared the various clinical outcomes between the two groups to identify which procedure had better immediate and long-term functional outcomes. The differences in mortality and occurrence of postoperative complications were also compared in patients with PELD versus controls.

RESULTS

Fifty-eight patients were enrolled (29 with PELD and 29 with OLMD). Both groups reported significant reductions in LBP and leg pain (p<0.01) postoperatively and an improvement in the ODI at 24 months postsurgery. The intergroup difference in the VAS for LBP at 1 day and 3 months was statistically significant (1.48 vs. 3.5, and 1.62 vs. 2.72, respectively; p=0.01 and 0.026, respectively) but the intergroup difference in the ODI was not. The mean length of hospital stay and the time to resumption of work were significantly shorter in the PELD group than in the OLMD group (2.55 vs. 3.21 days, and 4.45 vs. 6.62 weeks, respectively; p=0.037 and 0.01, respectively. There were no significant intergroup differences in terms of complications, recurrence, or procedure failures.

CONCLUSIONS

Both PELD and OLMD can provide equivalent, satisfactory outcomes. However, PELD demonstrated several potential advantages, including more rapid recovery and lower LBP early on. Further large-scale, randomized studies with long-term follow-up are now warranted.

Early Experience, Setup, Learning Curve, Benefits, and Complications Associated with Exoscope and Three-Dimensional 4K Hybrid Digital Visualizations in Minimally Invasive Spine Surgery

Study Design

Prospective observational study (n=74).

Purpose

To evaluate the learning curve for exoscope and three-dimensional (3D) 4K hybrid visualization in terms of operating time, advantages, disadvantages, and surgical complications in tubular-access minimally invasive spine surgery (MISS) and to assess surgeon satisfaction with image quality, ergonomics, and ability to perform target site treatment.

Overview of Literature

Working through tubular retractors poses a challenge. The extreme angulations during microsurgical decompression, especially contralateral decompression, require surgeons to work non-ergonomically. An exoscope allows surgeons to work ergonomically and independently of the microscope oculars as visualizations are now provided by large 3D 4K monitors. However, the value and efficacy of solely depending on an exoscope and 3D 4K monitors during microsurgical work are still unknown.

Methods

Seventy-four patients (99 levels) underwent trans-tubular MISS between March 2018 and January 2019. Five patients were excluded: one had pyogenic discitis, two had revisions, and two were trans-tubular transoral. In total, we analyzed 69 for operating time, blood loss, and complications. The learning curve graph was plotted using the surgical time for each procedure. Surgeons were asked to rate their satisfaction with image quality, ability to maintain ergonomic posture, and efficient target site treatment.

Results

For tubular microdiscectomy, the operating time plateaued after six cases, and for tubular decompression and minimally invasive transforaminal lumbar interbody fusion, the operating time plateaued after nine cases. Mean operating time was significantly reduced after the plateau. Complications included four cases of dural tear. All patients improved symptomatically, and there were no postoperative neurological deficits.

Conclusions

Use of the exoscope has a short learning curve. Surgeons benefit from improved ergonomic posture during surgery, and resident teaching appears to be good. The only drawback is the need to rearrange the operating table setup. Complications were comparable to those when using the surgical microscope. An exoscope with hybrid digital visualization provides excellent visualization, depth perception, clarity, and precision target site treatment.

Outcomes of endoscopic discectomy compared with open microdiscectomy and tubular microdiscectomy for lumbar disc herniations: a meta-analysis

OBJECTIVE

Endoscopic discectomy (ED) has been advocated as a less-invasive alternative to open microdiscectomy (OM) and tubular microdiscectomy (TM) for lumbar disc herniations, with the potential to decrease postoperative pain and shorten recovery times. Large-scale, objective comparisons of outcomes between ED, OM, and TM, however, are lacking. The authors' objective in this study was to conduct a meta-analysis comparing outcomes of ED, OM, and TM.

METHODS

The PubMed database was searched for articles published as of February 1, 2019, for comparative studies reporting outcomes of some combination of ED, OM, and TM. A meta-analysis of outcome parameters was performed assuming random effects.

RESULTS

Twenty-six studies describing the outcomes of 2577 patients were included. Estimated blood loss was significantly higher with OM than with both TM (p = 0.01) and ED (p < 0.00001). Length of stay was significantly longer with OM than with ED (p < 0.00001). Return to work time was significantly longer in OM than with ED (p = 0.001). Postoperative leg (p = 0.02) and back (p = 0.01) VAS scores, and Oswestry Disability Index scores (p = 0.006) at latest follow-up were significantly higher for OM than for ED. Serum creatine phosphokinase (p = 0.02) and C-reactive protein (p < 0.00001) levels on postoperative day 1 were significantly higher with OM than with ED.

CONCLUSIONS

Outcomes of TM and OM for lumbar disc herniations are largely equivalent. While this analysis demonstrated that several clinical variables were significantly improved in patients undergoing ED when compared with OM, the magnitude of many of these differences was small and of uncertain clinical relevance, and several of the included studies were retrospective and subject to a high risk of bias. Further high-quality prospective studies are needed before definitive conclusions can be drawn regarding the comparative efficacy of the various surgical treatments for lumbar disc herniations.

Quality of Life in Patients Undergoing Spine Surgery: Systematic Review and Meta-Analysis

STUDY DESIGN

Meta-analysis.

OBJECTIVE

Despite the increasing importance of tracking clinical outcomes using valid patient-reported outcome measures, most providers do not routinely obtain baseline preoperative health-related quality of life (HRQoL) data in patients undergoing spine surgery, precluding objective outcomes analysis in individual practices. We conducted a meta-analysis of pre- and postoperative HRQoL data obtained from the most commonly published instruments to use as reference values.

METHODS

We searched PubMed, EMBASE, and an institutional registry for studies reporting EQ-5D, SF-6D, and Short Form-36 Physical Component Summary scores in patients undergoing surgery for degenerative cervical and lumbar spinal conditions published between 2000 and 2014. Observational data was pooled meta-analytically using an inverse variance-weighted, random-effects model, and statistical comparisons were performed.

RESULTS

Ninety-nine articles were included in the final analysis. Baseline HRQoL scores varied by diagnosis for each of the 3 instruments. On average, postoperative HRQoL scores significantly improved following surgical intervention for each diagnosis using each instrument. There were statistically significant differences in baseline utility values between the EQ-5D and SF-6D instruments for all lumbar diagnoses.

CONCLUSIONS

The pooled HRQoL values presented in this study may be used by practitioners who would otherwise be precluded from quantifying their surgical outcomes due to a lack of baseline data. The results highlight differences in HRQoL between different degenerative spinal diagnoses, as well as the discrepancy between 2 common utility-based instruments. These findings emphasize the need to be cognizant of the specific instruments used when comparing the results of outcome studies.

Percutaneous Endoscopic Lumbar Discectomy Versus Posterior Open Lumbar Microdiscectomy for the Treatment of Symptomatic Lumbar Disc Herniation: A Systemic Review and Meta-Analysis

OBJECTIVE

The purpose of this systematic review and meta-analysis was to compare the clinical efficacy between percutaneous endoscopic lumbar discectomy (PELD) versus posterior open lumbar microdiscectomy (OLMD) for the treatment of symptomatic lumbar disc herniation.

METHODS

We performed a comprehensive retrieval of related studies in 4 electronic databases (PubMed, Embase, Web of Science, and the Cochrane Library). Randomized or nonrandomized controlled trials reported from January 1990 to December 2017 that compared PELD versus OLMD for the treatment of symptomatic lumbar disc herniation were acquired. The quality of randomized controlled trials was evaluated by the criteria of the Cochrane Back Review Group, and the quality of cohort studies was assessed according to the Newcastle-Ottawa Scale. The primary outcome measurements included preoperative and postoperative visual analog scale (VAS) score of sciatica; the Oswestry Disability Index (ODI) before and after surgery; the Excellent and Good outcome rate based on Macnab criteria. The secondary outcome measurements included the incidence of complication, residual disk, recurrence, and reoperation; operation time; hospital stay; and time to return to work. Two authors independently extracted data and assessed each study for quality.

RESULTS

Nine studies with 1585 patients were included in our meta-analysis. Two were randomized controlled trials and the remaining 7 were retrospective cohort studies. The forest plots showed that no statistically significant difference was observed between the 2 groups in terms of preoperative and postoperative VAS score of sciatica, ODI before and after surgery, the Excellent and Good outcome rate, the complication rate, and the incidence of recurrence and reoperation. However, the PELD group had a higher incidence of residual disk or incomplete decompression than did the OLMD group. In addition, no significant difference was detected in the operation time between the 2 groups, but the PELD group was associated with shorter hospital stay and time of return to work.

CONCLUSIONS

Based on the present meta-analysis, no significant difference existed in VAS and ODI scores between the 2 surgical procedures, and they were also similar in terms of operation time, complication rate, and incidence of recurrence and reoperation, but PELD showed shorter hospital stay and time of return to work. Thus, under the premise of careful manipulation and complete decompression, we consider that PELD is a relatively more minimally invasive technique, which could be an alternative to OLMD.

Transforaminal endoscopic discectomy versus conventional microdiscectomy for lumbar discherniation: a systematic review and meta-analysis

BACKGROUND

The open microdiscectomy is the most common surgical procedure for the decompression of radiculopathy caused by lumbar disk herniation. To date, a variety of minimally invasive (MI) techniques have been developed. In the last decades, endoscopic techniques have been developed to perform discectomy. The transforaminal endoscopic discectomy (TED) with posterolateral access evolved out of the development of endoscopic techniques.

METHODS

A systematic literature search was performed using the PubMed, EMBASE, and Cochrane Library databases for trials written in English. The randomized trials and observational studies that met our inclusion criteria were subsequently included. Two reviewers respectively extracted data and estimated the risk of bias. All statistical analyses were performed using Review Manager 5.3.

RESULTS

Five prospective and four retrospective studies involving 1527 patients were included. The results of the meta-analysis indicated that there were significant differences between the two groups in length of hospital stay (MD = - 8.41, 95% CI - 10.26, - 6.56; p value < 0.00001). However, there were no significant differences in the leg visual analog scale (VAS) scores, the Oswestry Disability Index (ODI) scores, and the incidence of complications and recurrence.

CONCLUSIONS

The transforaminal endoscopic discectomy is superior to open microdiscectomy in the length of hospital stay. However, there were no differences in leg pain, functional recovery, and incidence of complications between TED and MD in treating LDH.

Tubular microscopes discectomy versus conventional microdiscectomy for treating lumbar disk herniation: Systematic review and meta-analysis

BACKGROUND

The application of tubular microscopes discectomy (TMD) was supposed to have similar or better results than conventional microdiscectomy (CMD). However, this conclusion had not been verified by sufficient evidence. Therefore, the focus of this meta-analysis was to assess the efficiency, safety, and clinical outcome of these 2 surgical procedures for treating lumbar disk herniation (LDH).

METHODS

PubMed, Embase, and Cochrane Collaboration Central databases were searched for studies which compared the results of TMD and CMD for the treatment of LDH up to July 2017. Data analysis was conducted using RevMan 5.3. A standardized electronic form of 17 predefined criteria from the Consort statement was used for the quality assessment.

RESULTS

Eight randomized controlled trials (RCT) and 2 retrospective studies were included in this review, including 804 patients. The pooled analysis showed that there was no significant difference in operative time (P = .38), blood loss (P = .14), the length of hospital stay (P = .47), the rate of intraoperative complications (P = .79), postoperative complications (P = .16), dural tear (P = .87), the reoperation (P = .20), the short-term back visual analog scale (VAS) scores (P = .76), the long-term back VAS scores (P = .64), the short-term leg VAS scores (P = .09), the long-term leg VAS scores (P = .35), and the Oswestry disability index (ODI) scores (P = .41).

CONCLUSION

The results of this meta-analysis demonstrate that TMD and CMD are both safe and effective surgical procedures which can be recommended for treating LDH. Additionally, the conclusion should be cautiously treated, because it was reached in the context of limited amount of studies and relatively small sample size. Therefore, future studies with good design and more large samples are required to validate this conclusion.

Comparison of Outcomes of Percutaneous Endoscopic Lumbar Discectomy and Open Lumbar Microdiscectomy for Young Adults: A Retrospective Matched Cohort Study

OBJECTIVE

There have been only a few studies on surgical treatment of lumbar disc herniation (LDH) in young adults. In addition, previous studies do not provide detailed information on the surgical outcomes for young adults with LDH. The purpose of this study was to compare the outcome of transforaminal percutaneous endoscopic lumbar discectomy (PELD) and open lumbar microdiscectomy for active, young adults (age 20-25 years).

METHODS

We performed retrospective chart and radiography. The patients were divided into 2 groups according to the surgical methods. Group A included the patients who underwent transforaminal PELD, and Group B included the patients who underwent open lumbar microdiscectomy for LDH at L4/5. After we matched for several factors, 32 young patients in group A and 34 young patients in group B were analyzed. We compared the outcomes between the 2 groups in terms of clinical, radiologic, perioperative outcomes, and surgery-related complications.

RESULTS

The clinical results for leg pain and radiologic results for decompression were the same in both groups. Most of complications in the PELD group occurred in the early phase. The recurrence rate and operation failure rate was no difference between the groups. The PELD brought significant advantages in the following areas: back pain, operation time, blood loss, hospital stay, and return-to-work.

CONCLUSIONS

Although a learning curve is needed in order to become familiar with PELD, PELD seemed to be a good choice for disc herniation in the lumbar spine for active, young adults.