Double-blind evaluation of intradiscal chymopapain for herniated lumbar discs. Early results

Papain Injection Creates a Nucleotomy-like Cavity for Testing Gels in Intervertebral Discs

Biomaterials, such as hydrogels, have an increasingly important role in the development of regenerative approaches for the intervertebral disc. Since animal models usually resist biomaterial injection due to high intradiscal pressure, preclinical testing of the biomechanical performance of biomaterials after implantation remains difficult. Papain reduces the intradiscal pressure, creates cavities within the disc, and allows for biomaterial injections. But papain digestion needs time, and cadaver experiments that are limited to 24 h for measuring range of motion (ROM) cannot not be combined with papain digestion just yet. In this study, we successfully demonstrate a new organ culture approach, facilitating papain digestion to create cavities in the disc and the testing of ROM, neutral zone (NZ), and disc height. Papain treatment increased the ROM by up to 109.5%, extended NZ by up to 210.9%, and decreased disc height by 1.96 ± 0.74 mm. A median volume of 0.73 mL hydrogel could be injected after papain treatment, and histology revealed a strong loss of proteoglycans in the remaining nucleus tissue. Papain has the same biomechanical effects as known from nucleotomies or herniations and thus creates a disc model to study such pathologies in vitro. This new model can now be used to test the performance of biomaterials.

Enzymatic chemonucleolysis for lumbar disc herniation-an assessment of historical and contemporary efficacy and safety: a systematic review and meta-analysis

Lumbar disc herniation (LDH) is often managed surgically. Enzymatic chemonucleolysis emerged as a non-surgical alternative. This systematic review and meta-analysis aims to assess the efficacy and safety of chemonucleolytic enzymes for LDH. The primary objective is to evaluate efficacy through "treatment success" (i.e., pain reduction) and severe adverse events (SAEs) rates. Additionally, differences in efficacy and safety trends among chemonucleolytic enzymes are explored. Following our PROSPERO registered protocol (CRD42023451546) and PRISMA guidelines, a systematic search of PubMed and Web of Science databases was conducted up to July 18, 2023. Inclusion criteria involved human LDH treatment with enzymatic chemonucleolysis reagents, assessing pain alleviation, imaging changes, and reporting on SAEs, with focus on allergic reactions. Quality assessment employed the Cochrane Source of Bias and MINORS tools. Meta-analysis utilized odds ratios (OR) with 95% confidence intervals (CI). Among 62 included studies (12,368 patients), chemonucleolysis demonstrated an 79% treatment success rate and significantly outperformed placebo controls (OR 3.35, 95% CI 2.41-4.65) and scored similar to surgical interventions (OR 0.65, 95% CI 0.20-2.10). SAEs occurred in 1.4% of cases, with slightly higher rates in chymopapain cohorts. No significant differences in "proceeding to surgery" rates were observed between chemonucleolysis and control cohorts. Limitations include dated and heterogeneous studies, emphasizing the need for higher-quality trials. Further optimization through careful patient selection and advances in therapy implementation may further enhance outcomes. The observed benefits call for wider clinical exploration and adoption. No funding was received for this review.

Surgical versus non-surgical treatment for sciatica: systematic review and meta-analysis of randomised controlled trials

OBJECTIVE

To investigate the effectiveness and safety of surgery compared with non-surgical treatment for sciatica.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Medline, Embase, CINAHL, Cochrane Central Register of Controlled Trials, ClinicalTrials.gov, and the World Health Organisation International Clinical Trials Registry Platform from database inception to June 2022.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Randomised controlled trials comparing any surgical treatment with non-surgical treatment, epidural steroid injections, or placebo or sham surgery, in people with sciatica of any duration due to lumbar disc herniation (diagnosed by radiological imaging).

DATA EXTRACTION AND SYNTHESIS

Two independent reviewers extracted data. Leg pain and disability were the primary outcomes. Adverse events, back pain, quality of life, and satisfaction with treatment were the secondary outcomes. Pain and disability scores were converted to a scale of 0 (no pain or disability) to 100 (worst pain or disability). Data were pooled using a random effects model. Risk of bias was assessed with the Cochrane Collaboration's tool and certainty of evidence with the grading of recommendations assessment, development, and evaluation (GRADE) framework. Follow-up times were into immediate term (≤six weeks), short term (>six weeks and ≤three months), medium term (>three and <12 months), and long term (at 12 months).

RESULTS

24 trials were included, half of these investigated the effectiveness of discectomy compared with non-surgical treatment or epidural steroid injections (1711 participants). Very low to low certainty evidence showed that discectomy, compared with non-surgical treatment, reduced leg pain: the effect size was moderate at immediate term (mean difference -12.1 (95% confidence interval -23.6 to -0.5)) and short term (-11.7 (-18.6 to -4.7)), and small at medium term (-6.5 (-11.0 to -2.1)). Negligible effects were noted at long term (-2.3 (-4.5 to -0.2)). For disability, small, negligible, or no effects were found. A similar effect on leg pain was found when comparing discectomy with epidural steroid injections. For disability, a moderate effect was found at short term, but no effect was observed at medium and long term. The risk of any adverse events was similar between discectomy and non-surgical treatment (risk ratio 1.34 (95% confidence interval 0.91 to 1.98)).

CONCLUSION

Very low to low certainty evidence suggests that discectomy was superior to non-surgical treatment or epidural steroid injections in reducing leg pain and disability in people with sciatica with a surgical indication, but the benefits declined over time. Discectomy might be an option for people with sciatica who feel that the rapid relief offered by discectomy outweighs the risks and costs associated with surgery.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42021269997.

Low-Dose Collagenase Chemonucleolysis Combined with Radiofrequency in the Treatment of Lumbar Disc Herniation: A 10-Year Retrospective Study

Objective

This study explored the 10-year efficacy, safety, and prognostic factors of low-dose collagenase chemonucleolysis (CCNL) combined with radiofrequency (RF) in the treatment of lumbar disc herniation (LDH).

Methods

The data of 167 LDH patients were collected. Modified MacNab criteria, Numerical Rating Scale (NRS), and Japanese Orthopedic Association (JOA) scores were, respectively, used to evaluate patients' excellent and good rates, pain degree, and nerve function. The preoperative and 10-year postoperative patients' pain, numbness, and muscle weakness were compared. Patients' complications in perioperative period, recurrent/reappeared LDH, and reoperations were recorded. Finally, the independent risk factors affecting the long-time efficacy were assessed.

Results

A total of 126 patients were included. The patients' excellent and good rates were 86.51%–92.86% with no significant difference (P > 0.05). Postoperative NRS and JOA scores significantly improved (P < 0.01), most obvious within 6 months postoperatively. At 10 years postoperatively, 65.08%, 83.95%, and 93.02% of patients' pain, numbness, and muscle weakness were completely relieved (P < 0.05). Perioperative complications occurred in three patients with the rate of 2.38%. Recurrent/reappeared LDH patients were 11 with the ratio of 8.73%; nine of them underwent reoperations with the rate of 7.14%. And patients' probability of fair and poor efficacy at 10 years postoperatively with the course of disease >12 months and the responsibility disc ≥2 were, respectively, 6.005 and 4.227 times that of patients with the course of disease ≤12 months and the responsibility disc = 1 (P < 0.05).

Conclusion

The combined treatment is effective and safe in the long term. A course of disease >12 months and responsibility disc ≥2 independently reduce efficacy, and a course of disease >12 months has a more significant impact.

Nonsurgical medical treatment in the management of pain due to lumbar disc prolapse: A network meta-analysis

BACKGROUND

Evaluate the comparative effectiveness of treatment strategies for patients with pain due to lumbar disc prolapse (LDP).

METHODS

PubMed, EMBASE, and the Cochrane Database were searched through September 2017. Randomized controlled trials on LDP reporting on pain intensity and/or global pain effects which compared included treatments head-to-head, against placebo, and/or against conventional care were included. Study data were independently double-extracted and data on patient traits and outcomes were collected. Risk of bias was assessed using the Cochrane risk of bias tool. Separate Bayesian network meta-analyses were undertaken to synthesize direct and indirect, short-term and long-term outcomes, summarized as odds ratios (OR) or weighted mean differences (WMD) with 95% credible intervals (CI) as well as surface under the cumulative ranking curve (SUCRA) values.

RESULTS

58 studies in global effects and 74 studies in pain intensity analysis were included. Thirty-eight (65.5%) of these studies reported a possible elevated risk of bias. Autonomic drugs and transforminal epidural steroid injections (TESIs) had the highest SUCRA scores at short-term follow up (86.7 and 83.5 respectively), while Cytokines/Immunomodulators and TESI had the highest SUCRA values at long-term-follow-up in the global effect's analysis (86.6 and 80.9 respectively). Caudal steroid injections and TESIs had the highest SUCRA scores at short-term follow up (79.4 and 75.9 respectively), while at long-term follow-up biological agents and manipulation had the highest SUCRA scores (86.4 and 68.5 respectively) for pain intensity. Some treatments had few studies and/or no associated placebo-controlled trials. Studies often did not report on co-interventions, systematically differed, and reported an overall elevated risk of bias.

CONCLUSION

No treatment stands out as superior when compared on multiple outcomes and time periods but TESIs show promise as an effective short-term treatment. High quality studies are needed to confirm many nodes of this network meta-analysis.

Randomized clinical trial comparing lumbar percutaneous hydrodiscectomy with lumbar open microdiscectomy for the treatment of lumbar disc protrusions and herniations

OBJECTIVES:

Hydrodiscectomy is a new technique used for percutaneous spinal discectomy that employs a high-intensity stream of water for herniated disc ablation and tissue aspiration. No previous clinical study has examined the effects of percutaneous hydrodiscectomy. The aim of this study is to evaluate the outcomes of hydrodiscectomy compared to open microdiscectomy regarding pain, function, satisfaction, complications and recurrence rates.

METHODS:

In this randomized clinical trial, patients referred to our tertiary hospital for lumbar back pain were recruited and included in the study if they had disc protrusion or small herniation in only one level, without neurological deficits and with no resolution after six weeks of conservative treatment. One group underwent open microdiscectomy, and the other group underwent percutaneous microdiscectomy via hydrosurgery. Function was evaluated using the Oswestry Disability Index and pain was assessed using a visual analog scale. Evaluations were performed preoperatively, and then during the first week and at one, three, six and twelve months postoperatively. Personal satisfaction was verified. Clinicaltrials.gov: NCT01367860.

RESULTS:

During the study period, 20 patients were included in each arm and 39 completed one-year of follow-up (one patient died of unrelated causes). Both groups exhibited equal improvement on the visual analog scale and Oswestry evaluations after treatment, without any significant differences. The improvement in the lumbar visual analog scale score was not significant in the hydrodiscectomy group (p=0.138). The rates of infection, pain, recurrence and satisfaction were similar between the two groups.

CONCLUSION:

Percutaneous hydrodiscectomy was demonstrated to be as effective as open microdiscectomy for reducing pain. The rates of complications and recurrence of herniation were similar between groups. Patient satisfaction with the treatment was also similar between groups.

Comparative clinical effectiveness of management strategies for sciatica: systematic review and network meta-analyses

BACKGROUND

There are numerous treatment approaches for sciatica. Previous systematic reviews have not compared all these strategies together.

PURPOSE

To compare the clinical effectiveness of different treatment strategies for sciatica simultaneously.

STUDY DESIGN

Systematic review and network meta-analysis.

METHODS

We searched 28 electronic databases and online trial registries, along with bibliographies of previous reviews for comparative studies evaluating any intervention to treat sciatica in adults, with outcome data on global effect or pain intensity. Network meta-analysis methods were used to simultaneously compare all treatment strategies and allow indirect comparisons of treatments between studies. The study was funded by the UK National Institute for Health Research Health Technology Assessment program; there are no potential conflict of interests.

RESULTS

We identified 122 relevant studies; 90 were randomized controlled trials (RCTs) or quasi-RCTs. Interventions were grouped into 21 treatment strategies. Internal and external validity of included studies was very low. For overall recovery as the outcome, compared with inactive control or conventional care, there was a statistically significant improvement following disc surgery, epidural injections, nonopioid analgesia, manipulation, and acupuncture. Traction, percutaneous discectomy, and exercise therapy were significantly inferior to epidural injections or surgery. For pain as the outcome, epidural injections and biological agents were significantly better than inactive control, but similar findings for disc surgery were not statistically significant. Biological agents were significantly better for pain reduction than bed rest, nonopioids, and opioids. Opioids, education/advice alone, bed rest, and percutaneous discectomy were inferior to most other treatment strategies; although these findings represented large effects, they were statistically equivocal.

CONCLUSIONS

For the first time, many different treatment strategies for sciatica have been compared in the same systematic review and meta-analysis. This approach has provided new data to assist shared decision-making. The findings support the effectiveness of nonopioid medication, epidural injections, and disc surgery. They also suggest that spinal manipulation, acupuncture, and experimental treatments, such as anti-inflammatory biological agents, may be considered. The findings do not provide support for the effectiveness of opioid analgesia, bed rest, exercise therapy, education/advice (when used alone), percutaneous discectomy, or traction. The issue of how best to estimate the effectiveness of treatment approaches according to their order within a sequential treatment pathway remains an important challenge.

Effect of a blend of comfrey root extract (Symphytum officinale L.) and tannic acid creams in the treatment of osteoarthritis of the knee: randomized, placebo-controlled, double-blind, multiclinical trials

OBJECTIVE

The purpose of this study was to determine the effect of 2 concentrations of topical, comfrey-based botanical creams containing a blend of tannic acid and eucalyptus to a eucalyptus reference cream on pain, stiffness, and physical functioning in those with primary osteoarthritis of the knee.

METHODS

Forty-three male and female subjects (45-83 years old) with diagnosed primary osteoarthritis of the knee who met the inclusion criteria were entered into the study. The subjects were randomly assigned to 1 of 3 treatment groups: 10% or 20% comfrey root extract (Symphytum officinale L.) or a placebo cream. Outcomes of pain, stiffness, and functioning were done on the Western Ontario and MacMaster Universities Osteoarthritis Index. Participants applied the cream 3× a day for 6 weeks and were evaluated every 2 weeks during the treatment.

RESULTS

Repeated-measures analyses of variance yielded significant differences in all of the Western Ontario and MacMaster Universities Osteoarthritis Index categories (pain P < .01, stiffness P < .01, daily function P < .01), confirming that the 10% and 20% comfrey-based creams were superior to the reference cream. The active groups each had 2 participants who had temporary and minor adverse reactions of skin rash and itching, which were rapidly resolved by modifying applications.

CONCLUSION

Both active topical comfrey formulations were effective in relieving pain and stiffness and in improving physical functioning and were superior to placebo in those with primary osteoarthritis of the knee without serious adverse effects.

Management of the herniated lumbar disc: the outcome after chemonucleolysis, surgical disc excision and conservative treatments

In the 11-year period from 1978 and 1988, myelography was performed on 624 patients with suspected herniated lumbar discs. Positive findings, defined as an indentation of the contrast-filled dural sac and/or lack of contrast filling of the nerve roots, were found in 508 (81.4%) patients. Patients with suspected spinal stenosis were excluded from the study. The choice of treatment was determined by the preference of the consultant in charge. In all, 146 patients were treated by chemonucleolysis, 152 patients underwent surgical excision of the disc via laminectomy/fenestration, while 210 patients were listed for further treatment (albeit chemonucleolysis or laminectomy) but sustained relief of symptoms whilst waiting for admission or refused further intervention and consequently continued conservative treatments (such as physiotherapy, manipulations under anaesthetic, epidural or local injections). Following a repetitive questionnaire and clinical review, 78% of those patients that had undergone chemonucleolysis were satisfied with their treatment (i.e. symptoms were either 'gone', 'much better' or 'better'). Significantly fewer patients were satisfied after surgical disc excision or conservative treatments (71% and 61%, respectively; P <0.001). Whereas patients with a short duration of symptoms (less than 1 year) achieved the best outcome after chemonucleolysis and laminectomy, patients with a prolonged history (greater than 2 years) benefitted most from conservative methods. Of those patients in whom symptoms were considered to be worse or the same following treatment, 46%, 51% and 42% were still working following chemonucleolysis, surgery and conservative treatment, respectively. The outcome did not depend upon the size of the disc involved. Although this is a retrospective study, it is the first report to compare the outcome following chemonucleolysis, surgery and conservative methods in patients with disc prolapse confirmed by myelography.

Nonsurgical interventional therapies for low back pain: a review of the evidence for an American Pain Society clinical practice guideline

STUDY DESIGN

Systematic review.

OBJECTIVE

To systematically assess benefits and harms of nonsurgical interventional therapies for low back and radicular pain.

SUMMARY OF BACKGROUND DATA

Although use of certain interventional therapies is common or increasing, there is also uncertainty or controversy about their efficacy.

METHODS

Electronic database searches on Ovid MEDLINE and the Cochrane databases were conducted through July 2008 to identify randomized controlled trials and systematic reviews of local injections, botulinum toxin injection, prolotherapy, epidural steroid injection, facet joint injection, therapeutic medial branch block, sacroiliac joint injection, intradiscal steroid injection, chemonucleolysis, radiofrequency denervation, intradiscal electrothermal therapy, percutaneous intradiscal radiofrequency thermocoagulation, Coblation nucleoplasty, and spinal cord stimulation. All relevant studies were methodologically assessed by 2 independent reviewers using criteria developed by the Cochrane Back Review Group (for trials) and by Oxman (for systematic reviews). A qualitative synthesis of results was performed using methods adapted from the US Preventive Services Task Force.

RESULTS

For sciatica or prolapsed lumbar disc with radiculopathy, we found good evidence that chemonucleolysis is moderately superior to placebo injection but inferior to surgery, and fair evidence that epidural steroid injection is moderately effective for short-term (but not long-term) symptom relief. We found fair evidence that spinal cord stimulation is moderately effective for failed back surgery syndrome with persistent radiculopathy, though device-related complications are common. We found good or fair evidence that prolotherapy, facet joint injection, intradiscal steroid injection, and percutaneous intradiscal radiofrequency thermocoagulation are not effective. Insufficient evidence exists to reliably evaluate other interventional therapies.

CONCLUSION

Few nonsurgical interventional therapies for low back pain have been shown to be effective in randomized, placebo-controlled trials.

Sources of sacroiliac region pain: insights gained from a study comparing standard intra-articular injection with a technique combining intra- and peri-articular injection

OBJECTIVES

To present evidence supporting the existence of extra-articular sources for sacroiliac region pain and to present evidence that intra-articular anesthetic blockade may underestimate the true prevalence of sacroiliac region pain.

DESIGN

Retrospective review of 2 large case series comparing patient responses to intra-articular injection versus combined intra-articular and peri-articular injection of anesthetic and corticosteroid.

SETTING

Private practice chronic pain clinic set in a hospital outpatient clinic.

PARTICIPANTS

Patients (N=120) sequentially enrolled from practice billing records. Inclusion criteria included pain in the low back below L4 and in the buttock, thigh, groin, or lower leg. If disk herniation, lumbar stenosis, or facet syndrome was previously treated with appropriately chosen injections, response to treatment had to be negative. Patients failed to respond to treatment with physical therapy. Exclusion criteria included records with an incomplete database, patients increasing pain medication use greater than 15% for pain not related to the sacroiliac region, severe psychiatric illness, and nonspecific anesthetic blockade. One hundred sixty-seven records were reviewed to obtain the 120 study subjects.

INTERVENTIONS

Intra-articular injection was done according to the standard technique described by Fortin. Peri-articular injection was done by a slight modification of the procedure described by Yin.

MAIN OUTCOME MEASURES

Percentage change in visual analog scale (VAS) pain scores at 3 weeks and 3 months postinjection; patients' self reported activities of daily living (ADLs) improvement at 3 weeks and 3 months postinjection; and percentage change in VAS pain score within 1 hour of injection.

RESULTS

For intra-articular injection alone, the rate of positive response at 3 months was 12.50% versus 31.25% for the combined injection (P=.025). Positive response was defined as greater than 50% drop in VAS pain score or patients describing ADLs as "greatly improved." Anesthetic response rates were higher in the combined injection group (62.5% vs 42.5%; P=.037).

CONCLUSIONS

Significant extra-articular sources of sacroiliac region pain exist. Intra-articular diagnostic blocks underestimate the prevalence of sacroiliac region pain.

Percutaneous Laser Disc Decompression for the Treatment of Lumbar Disc Herniation: A Review

BACKGROUND

Discontinuation of the marketing of chymodactin has reawakened interest in other percutaneous techniques for treating lumbar disc herniation. Developed in the 1980s, the concept of laser disc decompression is based on the percutaneous introduction of an optical fiber into the intervertebral disc and administering laser energy. The procedure allows for the vaporization of a small amount of the nucleus pulposus and hence a reduction in the intradisc pressure and relief of radicular pain.

OBJECTIVES

To review of the literature and summarize the technical modalities, mechanism, indications for, and results of percutaneous laser disc decompression for treating lumbar disc herniation.

METHODS

We identified studies of percutaneous laser disc decompression published between January 1980 and June 2006 in the MEDLINE, EMBASE, and Cochrane Library databases. The search terms used were percutaneous laser disc decompression, laser, and spine or lumbar, disc or disk. The articles underwent a stepwise selection process on the basis of their title, abstract, and full text.

RESULTS

Experimental and clinical studies have investigated the modality of percutaneous laser disc decompression, but no consensus exists on the type of laser to use, the wavelength, duration of application, or appropriate energy applied. Studies have evaluated the impact of different techniques on the amount of disc removed, intradisc pressure, and damage to neighboring tissue. Several open studies have been published, but their methodology and conclusions are questionable, and no controlled study has been performed.

CONCLUSIONS

Although the concept of laser disc nucleotomy is appealing, this treatment cannot be considered validated for disc herniation-associated radiculopathy resistant to medical treatment.

Surgical interventions for lumbar disc prolapse: updated Cochrane Review

STUDY DESIGN

An updated Cochrane Review.

OBJECTIVES

To assess the effects of surgical interventions for the treatment of lumbar disc prolapse.

SUMMARY OF BACKGROUND DATA

Disc prolapse accounts for 5% of low back disorders yet is one of the most common reasons for surgery. There is still little scientific evidence supporting some interventions.

METHODS

Use of standard Cochrane review methods to analyze all randomized controlled trials published up to January 1, 2007.

RESULTS

Forty randomized controlled trials (RCTs) and 2 quasi-RCTs were identified. Many of the early trials were of some form of chemonucleolysis, whereas the majority of the later studies either compared different techniques of discectomy or the use of some form of membrane to reduce epidural scarring. Four trials directly compared discectomy with conservative management, and these give suggestive rather than conclusive results. However, other trials show that discectomy produces better clinical outcomes than chemonucleolysis, and that in turn is better than placebo. Microdiscectomy gives broadly comparable results to standard discectomy. Recent trials of an interposition gel covering the dura (5 trials) and of fat (4 trials) show that they can reduce scar formation, although there is limited evidence about the effect on clinical outcomes. There is insufficient evidence on other percutaneous discectomy techniques to draw firm conclusions. Three small RCTs of laser discectomy do not provide conclusive evidence on its efficacy. There are no published RCTs of coblation therapy or transforaminal endoscopic discectomy.

CONCLUSION

Surgical discectomy for carefully selected patients with sciatica due to lumbar disc prolapse provides faster relief from the acute attack than conservative management, although any positive or negative effects on the lifetime natural history of the underlying disc disease are still unclear. The evidence for other minimally invasive techniques remains unclear except for chemonucleolysis using chymopapain, which is no longer widely available.

Surgical interventions for lumbar disc prolapse

BACKGROUND

Disc prolapse accounts for five percent of low-back disorders but is one of the most common reasons for surgery.

OBJECTIVES

The objective of this review was to assess the effects of surgical interventions for the treatment of lumbar disc prolapse.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials, MEDLINE, PubMed, Spine and abstracts of the main spine society meetings within the last five years. We also checked the reference lists of each retrieved articles and corresponded with experts. All data found up to 1 January 2007 are included.

SELECTION CRITERIA

Randomized trials (RCT) and quasi-randomized trials (QRCT) of the surgical management of lumbar disc prolapse.

DATA COLLECTION AND ANALYSIS

Two review authors assessed trial quality and extracted data from published papers. Additional information was sought from the authors if necessary.

MAIN RESULTS

Forty RCTs and two QRCTs were identified, including 17 new trials since the first edition of this review in 1999. Many of the early trials were of some form of chemonucleolysis, whereas the majority of the later studies either compared different techniques of discectomy or the use of some form of membrane to reduce epidural scarring. Despite the critical importance of knowing whether surgery is beneficial for disc prolapse, only four trials have directly compared discectomy with conservative management and these give suggestive rather than conclusive results. However, other trials show that discectomy produces better clinical outcomes than chemonucleolysis and that in turn is better than placebo. Microdiscectomy gives broadly comparable results to standard discectomy. Recent trials of an inter-position gel covering the dura (five trials) and of fat (four trials) show that they can reduce scar formation, though there is limited evidence about the effect on clinical outcomes. There is insufficient evidence on other percutaneous discectomy techniques to draw firm conclusions. Three small RCTs of laser discectomy do not provide conclusive evidence on its efficacy, There are no published RCTs of coblation therapy or trans-foraminal endoscopic discectomy.

AUTHORS' CONCLUSIONS

Surgical discectomy for carefully selected patients with sciatica due to lumbar disc prolapse provides faster relief from the acute attack than conservative management, although any positive or negative effects on the lifetime natural history of the underlying disc disease are still unclear. Microdiscectomy gives broadly comparable results to open discectomy. The evidence on other minimally invasive techniques remains unclear (with the exception of chemonucleolysis using chymopapain, which is no longer widely available).

Surgical interventions for lumbar disc prolapse

BACKGROUND

Disc prolapse accounts for five percent of low-back disorders but is one of the most common reasons for surgery.

OBJECTIVES

The objective of this review was to assess the effects of surgical interventions for the treatment of lumbar disc prolapse.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials, MEDLINE, PubMed, Spine and abstracts of the main spine society meetings within the last five years. We also checked the reference lists of each retrieved articles and corresponded with experts. All data found up to 1 June 2006 are included.

SELECTION CRITERIA

Randomized trials (RCT) and quasi-randomized trials (QRCT) of the surgical management of lumbar disc prolapse.

DATA COLLECTION AND ANALYSIS

Two review authors assessed trial quality and extracted data from published papers. Additional information was sought from the authors if necessary.

MAIN RESULTS

Thirty-nine RCTs and two QRCTs were identified, including 16 new trials since the first edition of this review in 1999. Many of the early trials were of some form of chemonucleolysis, whereas the majority of the later studies either compared different techniques of discectomy or the use of some form of membrane to reduce epidural scarring. Despite the critical importance of knowing whether surgery is beneficial for disc prolapse, only three trials have directly compared discectomy with conservative management and these give suggestive rather than conclusive results. However, other trials show that discectomy produces better clinical outcomes than chemonucleolysis and that in turn is better than placebo. Microdiscectomy gives broadly comparable results to standard discectomy. Recent trials of an inter-position gel covering the dura (five trials) and of fat (four trials) show that they can reduce scar formation, though there is limited evidence about the effect on clinical outcomes. There is insufficient evidence on other percutaneous discectomy techniques to draw firm conclusions. Three small RCTs of laser discectomy do not provide conclusive evidence on its efficacy, There are no published RCTs of coblation therapy or trans-foraminal endoscopic discectomy.

AUTHORS' CONCLUSIONS

Surgical discectomy for carefully selected patients with sciatica due to lumbar disc prolapse provides faster relief from the acute attack than conservative management, although any positive or negative effects on the lifetime natural history of the underlying disc disease are still unclear. Microdiscectomy gives broadly comparable results to open discectomy. The evidence on other minimally invasive techniques remains unclear (with the exception of chemonucleolysis using chymopapain, which is no longer widely available).

[Nucleolysis in the herniated disk]

Back pain associated with a herniated disk has become an important and increasing general health problem in Germany and other industrialized countries. After all methods of conservative treatment have been exhausted, nucleolysis may be a minimally invasive alternative to surgery. In nucleolysis, chondrolytic substances or other substances, which reduce the pressure within the disk by other means, are injected into the nucleus pulposus under CT guidance. Among various substances, which have been employed for nucleolysis, an ozone-oxygen mixture appears to be very promising. The water-binding capacity of ozone results in a reduction of pain for several months. Moreover, it has an anti-inflammatory effect and results in an increase of perfusion. Ozone is converted into pure oxygen in the body and has a low allergic potential. Recent minimally invasive therapeutic methods such as percutaneous nucleotomy or laser treatment do not result in superior results compared with nucleolysis.

Outcome of invasive treatment modalities on back pain and sciatica: an evidence-based review

Within the framework of evidence-based medicine high-quality randomised trials and systematic reviews are considered a necessary prerequisite for progress in orthopaedics. This paper summarises the currently available evidence on surgical and other invasive procedures for low back pain. Results of systematic reviews conducted within the framework of the Cochrane Back Review Group were used. Data were gathered from the latest Cochrane Database of Systematic Reviews 2005, Issue 2. The Cochrane reviews were updated using the evidence summary on surgery and other invasive procedures from the COST B13 European Guidelines for the Management of Acute and Chronic Non-Specific Low Back Pain. Facet joint, epidural, trigger point and sclerosant injections have not clearly been shown to be effective and can consequently not be recommended. There is no scientific evidence on the effectiveness of spinal stenosis surgery. Surgical discectomy may be considered for selected patients with sciatica due to lumbar disc prolapses that fail to resolve with the conservative management. Cognitive intervention Combined with exercises is recommended for chronic low back pain, and fusion surgery may be considered only in carefully selected patients after active rehabilitation programmes during 2 years time have failed. Demanding surgical fusion techniques are not better than the traditional posterolateral fusion without internal fixation.

Current Concepts in Minimally Invasive Discectomy

OBJECTIVE

The purpose of this study was to evaluate the various minimally invasive procedures available for the treatment of lumbar disc disease.

METHODS

A review of the literature, as well as my personal experience with minimally invasive approaches to the lumbar discs, was performed. This review included the percutaneous and open surgical approaches currently available and used for the treatment of lumbar disc disease.

RESULTS

The primary minimally invasive procedures for the treatment of lumbar disc disease include the following: 1) chemonucleolysis, introduced by Lyman Smith in 1964; 2) percutaneous manual nucleotomy, introduced by Hijikata in 1975; 3) microdiscectomy, first performed by Yaşargil in 1968; 4) automated percutaneous lumbar discectomy, introduced by Onik in 1984; 5) laser discectomy, first performed by Ascher and Choy in 1987; 6) endoscopic discectomy, first used by Schreiber and Suezawa in 1986 and improved by Mayer, Brock, and Mathews; 7) microendoscopic discectomy, introduced by Smith and Foley in 1995; and 8) intradiscal electrothermy, first reported by Saal and Saal in 2000.

CONCLUSION

Although all percutaneous techniques have been reported to yield high success rates, to date no studies have demonstrated any of these to be superior to microsurgical discectomy, which continues to be regarded as the standard with which all other techniques must be compared.

Surgical management of cervical and lumbosacral radiculopathies: indications and outcomes

The most common indication for the surgical management of compressive cervical and lumbar radiculopathies is a herniated disc in a patient who has not improved with conservative management. Even though a herniated disk is a common condition, it is paramount that the examining physician considers an extensive differential diagnosis when evaluating radiculopathies, especially in patients with a history of cancer, multiple medical illnesses, secondary gain, or advanced age. This consideration has become even more important as imaging studies have improved, because previously undetected degenerative changes are now clearly visualized on MRI and CT scans. These improved studies, however, do not replace a thorough history and physical examination, because a patient's signs and symptoms may not correlate with the radiographic findings. The authors have presented a series of surgical techniques used to manage cervical and lumbar discectomies to the most recent "minimally invasive" percutaneous techniques. Much debate and controversy surround these more recent techniques. There is no controversy, however, in stating that achieving good outcomes, regardless of technique, is predicated on proper patient selection. Because patient selection is the most important predictor of outcome and because serious complications have been reported with "minimally invasive" percutaneous procedures, the authors continue to advocate the proven traditional surgical approaches until prospective, randomized studies demonstrate a clear benefit to using alternative techniques.

Five-year results from chemonucleolysis with chymopapain or collagenase: a prospective randomized study

STUDY DESIGN

A 5-year clinical follow-up assessment of a prospective randomized study of chemonucleolysis using chymopapain (4000 IU) or collagenase (400 ABC units) was performed.

SUMMARY OF BACKGROUND DATA

Intradiscal therapy can be performed for patients with contained discs by chemonucleolysis, percutaneous discectomy, or laser ablation. The oldest intradiscal therapy is chemonucleolysis with chymopapain.

OBJECTIVE

The purpose of this study was to compare prospectively the efficacy of chymopapain and collagenase for intradiscal injection.

METHODS

In this study, 100 patients with indication for intradiscal therapy were prospectively randomized to treatment with either chymopapain or collagenase. All the injections were performed by the double-needle technique with the patient under general anesthesia. The mean age of the patients was 35.5 years in the chymopapain group and 38 years in the collagenase group. An equal number of injections was performed at L4-L5 and L5-S1.

RESULTS

After 5 years, good and excellent results were observed in 72% of the chymopapain group and 52% of the collagenase group when the surgically treated and lost patients were graded as poor. Using a scale of 0 (no pain) to 10 (intractable pain), the pain level dropped from 8.5 to 0.7 in the chymopapain group and from 8.6 to 0.9 in the collagenase group. Microdiscectomy at the injected level was required for 23 patients (14 in the collagenase group and 9 in the chymopapain group).

CONCLUSIONS

After 5 years, no deterioration had occurred, as compared with the 1-year follow-up assessment. Chymopapain has proved to be safe, with one minor anaphylactic reaction, and effective even over the long term. Collagenase may need further study and cannot be recommended at this time.

Review of safety in endoscopic laser foraminoplasty for the management of back pain

OBJECTIVE

The purpose of this study was to analyze the incidence and gravity of reported complications that arise in spinal surgery and assess the comparative safety, or otherwise, of endoscopic laser foraminoplasty (ELF).

BACKGROUND DATA

Chemonucleolysis, decompression, discectomy, and fusion have long been cited as treatments for chronic low back pain. Over recent years newer, less invasive surgical techniques have become available, one such being ELF. Although minimally invasive, the beneficial outcome must be interpreted in relation to concerns regarding the safety of the procedure and its risks relative to those of other forms of spinal surgery. The Spinal Foundation, Rochdale has performed 958 ELFs and has collated a comprehensive database of the results of all these operations. These prospective records provided the basis for a comparison of the safety of ELF to that reported with other spinal surgical techniques.

METHODS

A total of 958 procedures have been performed on 716 patients. Complications that arose during the operation and the postoperative phase of 6 weeks following the procedure were elicited from patient records. These data were correlated and compared to a meta-analysis of randomized controlled clinical trial data of complications arising during and after conventional spinal surgery. The SPSS (statistical package for social sciences) and CIA (confidence interval analysis) statistical packages were used to draw conclusions regarding the safety of ELF.

RESULTS

The cohort integrity of operation and outpatient review records at 6 weeks after surgery was 100%. In 958 ELFs performed, 24 complications occurred in 23 patients. There were 9 cases of discitis (1 infective, 8 aseptic) (0.9%), 1 dural tear (0.1%), 1 deep wound infection (0.1%), 2 patients suffered a foot drop (1 transient) (0.2%), 1 myocardial infarction (0.1%), 1 erectile dysfunction (0.1%), and 1 patient who developed panic attacks post-operatively (0.1%). This amounts to an overall surgical complication rate of 1.6%. Magnetic resonance imaging (MRI) follow up of clinically symptomatic patients highlighted 8 residual disc herniations (0.8%). Meta-analysis of randomized controlled trials of conventional spinal surgery for adult onset degenerative disc disease and/or sciatic pain reported overall complication rates for fusion (11.8%), decompression (7.6%), discectomy (6.0%), and chemonucleolysis (9.6%).

CONCLUSIONS

The complication rate of ELF is shown to be significantly lower than that reported following conventional spinal surgery (p < 0.01). From these results, we conclude that ELF as a treatment for chronic low back pain and sciatica presents less risk to a patient than conventional methods of spinal surgery.

The Cochrane review of surgery for lumbar disc prolapse and degenerative lumbar spondylosis

STUDY DESIGN

A Cochrane review of randomized controlled trials.

OBJECTIVES

To collate the scientific evidence on surgical management for lumbar-disc prolapse and degenerative lumbar spondylosis.

SUMMARY OF BACKGROUND DATA

Surgical investigations and interventions account for as much as one third of the health care costs for spinal disorders, but the scientific evidence for most procedures still is unclear.

METHODS

A highly sensitive search strategy identified all published randomized controlled trials. Cochrane methodology was used for meta-analysis of the results.

RESULTS

Twenty-six randomized controlled trials of surgery for lumbar disc prolapse and 14 trials of surgery for degenerative lumbar spondylosis were identified. Methodologic weaknesses were found in many of the trials. Only one trial directly compared discectomy and conservative management. Meta-analyses showed that surgical discectomy produces better clinical outcomes than chemonucleolysis, which is better than placebo. Three trials showed no difference in clinical outcomes between microdiscectomy and standard discectomy, but in three other studies, both produced better results than percutaneous discectomy. Three trials showed that inserting an interposition membrane after discectomy does not significantly reduce scar formation or alter clinical outcomes. Five heterogeneous trials on spinal stenosis and degenerative spondylolisthesis permit very limited conclusions. There were nine trials of instrumented versus noninstrumented fusion: Meta-analysis showed that instrumentation may facilitate fusion but does not improve clinical outcomes.

CONCLUSIONS

There is now strong evidence on the relative effectiveness of surgical discectomy versus chemonucleolysis versus placebo. There is considerable evidence on the clinical effectiveness of discectomy for carefully selected patients with sciatica caused by lumbar disc prolapse that fails to resolve with conservative management. There is no scientific evidence on the effectiveness of any form of surgical decompression or fusion for degenerative lumbar spondylosis compared with natural history, placebo, or conservative management. The Cochrane reviews will be updated continuously as other trials become available.

Intraoperative chymopapain in lumbar laminotomy for disc disease: a less invasive technique

The use of chymopapain in the treatment of lumbar disc herniation has been widely studied since Smith first described its use in humans in 1963. The authors describe the use of chymopapain intraoperatively in open lumbar microdiscectomy in 63 patients. When combined with the results of a previous study performed at the same institution, the authors found that this technique significantly reduces the rate of recurrent disc herniation when compared with traditional laminotomy with discectomy. This procedure maximizes the benefits of each approach taken separately, allowing for decompression of the nerve root from a free fragment or sequestered disc and preventing recurrence through dissolution of the nucleus pulposus. Overall, outcome was good or excellent immediately postoperatively in 73% of the 63 patients and in 64% at last follow-up evaluation. Additionally, this procedure is safe with no complications noted in the immediate perioperative period or at follow-up evaluation.

[Current therapeutic options in sciatica caused by disk herniation]

The results of reliable therapeutic trials, experimental studies showing that compression is not the only mechanism of nerve root alterations, and mainly, the favorable spontaneous outcome of 95% of the sciatica command a critical approach of all the treatments of sciatica by disc herniation. A disc herniation can be observed in 20% of asymptomatic population. Except neurological complications requiring an early surgical decompression, the management of sciatica should begin by a 2 to 3 months period of medical treatment including analgesic drugs or NSAID, a 8 to 10 day bed rest, epidural corticosteroid injections validated in controlled studies, and a lumbar brace during 4 to 6 weeks. The reference treatment of disc herniation in patients whose conservative treatment failed is conventional surgery. The average rate of failure following decompressive surgery is 15 to 20% and the need for further surgery ranges from 5 to 15%. The main cause of failure is the absence of true compressive herniation before the initial operation. Microscope removal of disc herniation does not lead to better results than the standard procedure and there is a 20% risk of recurrence when only the herniated fragment is removed. The success rate of chemonucleolysis approaches 65-70% but the procedure need a strict care to prevent severe complications. Manual percutaneous discectomy, whatever the procedure are supported only by uncontrolled studies. The only randomized trial in automated percutaneous discectomy versus chemonucleolysis reported a 37% success rate with a one-year follow-up. Benefit/risk ratio should always be considered before every treatment of sciatica.

Chemonucleolysis versus discectomy: a randomized multicenter trial

A randomized clinical trial was carried out to compare the results of open discectomy with those of chemonucleolysis in 151 patients suffering from a disc herniation at L4-5 or L5-S1. All patients fulfilled strict entry criteria; 78 patients underwent open discectomy and 73 were subjected to chemonucleolysis. An increase in radicular pain immediately after treatment was encountered in 16 patients (22%) in the chemonucleolysis group, as compared to none in the discectomy group. The efficacy of discectomy appeared to be definitely superior to that of chemonucleolysis. Within a follow-up period of 1 year, 18 patients (25%) required open discectomy following failed chemonucleolysis; two patients (3%) in the discectomy group needed a second operation. Open discectomy following previous chemonucleolysis was successful in only 44% of cases. Comparison of the final results of the two modes of treatment 12 months after the last intervention (including second treatment) did not reveal any significant differences. The duration of the preoperative symptoms, the level of disc herniation, and the leakage of contrast medium out of the disc appeared to be of no relevance to the final outcome. The complication rates in both treatment groups were low.

Chemonucleolysis with chymopapain: results in 150 patients

Chemonucleolysis with chymopapain has been advocated for the treatment of lumbar disc disease. When polled by a mail questionnaire, 150 consecutive patients who had undergone chemonucleolysis reported an overall success rate of only 40% and a failure rate of 60%. However, 57% of the patients were active or had only mild restriction of daily activities. Of those patients employed prior to injection, only 63% had returned to work. Those with workmen's compensation benefits fared considerably worse than those covered by third-party insurance (17% vs. 51% success). These results cast doubt on the long-term benefits of chymopapain in the treatment of lumbar disc disease.

The MMPI and psychological factors in chronic low back pain: a review

The Minnesota Multiphasic Personality Inventory (MMPI) is widely used in the psychological assessment of patients with chronic low back pain (LBP). Patients' profiles have been used in a number of ways: in attempts to discriminate between cases; as predictors of both medical treatment and pain management program outcomes; and in attempts to assess degree of disability. Studies reviewed here indicate that the concept of psychological etiology of chronic LBP, despite widespread use, has failed to differentiate patients and to reliably predict response to specific treatment. A promising alternative approach has emerged in recent years: profile distinctions between different types of psychological response to chronic LBP. These subgroups are associated with different pain-related behaviors and may show differential response to various treatments, although further work remains to be done to specify the relationships more precisely. Methodological difficulties that continue to appear in the literature are addressed and recommendations for further developments in the use of the MMPI with this patient population are made.

Percutaneous nucleotomy. An alternative to spinal surgery

As an alternative to the well-established surgical procedures for the treatment of disk herniation, percutaneous nucleotomy has proved to be very satisfactory. In several cases this approach has brought complete relief to the patient without sacrifice of bone and without causing soft tissue damage as would have been inevitable with the usual surgical methods. Percutaneous nucleotomy is also a true alternative to chemical nucleolysis when leakage of contrast agent into the spinal canal has already been observed during diskography. Furthermore, this method avoids disagreeable complications encountered in chemical nucleotomy, for example, anaphylactic shock or the escape of the nucleolytic agent into the spinal canal. The method basically consists of removing the nucleus pulposus (or a major part of it) by means of a forceps that is introduced to the site through a cannula. In this manner a reduction of volume of the disk is achieved. The procedure can easily be carried out under local anesthesia. This method should be avoided in the case of prolapse within the spinal canal and especially when displacement beyond the level of the disk has occurred. In the period between 1979 and 1985 we carried out percutaneous nucleotomies in 51 patients with herniation mostly combined with a narrow spinal canal or spondylolisthesis. The clinical results from 32 of 51 patients can be assessed as very good, good, or satisfactory. We consider the proportion of patients showing good clinical results to be high, bearing in mind that the indication was not just disk herniation alone but, in most cases, combined with other lumbar pathologies as well.

Chemonucleolysis: an evolving concept and clinical review

Chemonucleolysis has had a controversial 20 years of probation, and despite growing clinical evidence supporting the efficacy of chymopapain, the concept is still disputed. To evaluate chemonucleolysis 84 patients, treated with chymopapain over 12 months, were assessed before injection and reviewed 5-15 months after injection. All patients had lumbar disc disease which had failed to respond to conservative therapy. Chemonucleolysis was most effective in those patients with classical signs and symptoms of prolapsed lumbar disc disease of less than 3 months' duration and where sciatica was the predominant complaint. Poor results were obtained in those patients with pain for more than 6 months' duration and with predominantly low back pain. Workers' compensation patients did not respond favourably. Good short term results with chemonucleolysis can be expected by careful patient selection and adequate and accurate placement of enzyme.

Multiple cerebral hemorrhages following chymopapain chemonucleolysis. Case report

A case of multiple cerebral hemorrhages following chymopapain chemonucleolysis is reported. The authors believe the probable etiology was intrathecal extravasation of chymopapain after injection of the drug into a lumbar disc space.

Chymopapain

Chymopapain is a proteolytic enzyme injected intradiscally for the treatment of herniated lumbar discs. The average success rate is 73 percent for elimination of backache and sciatica. Side effects occur in three percent of patients, the most serious being anaphylaxis in about one percent. A majority of patients experience severe back pain or spasms during the first 24-48 hours after treatment. This treatment modality consumes fewer hospital days and produces a quicker return to work than does surgery. It does not affect subsequent surgical procedures adversely. Chymopapain chemonucleolysis is safe and effective when administered by experienced physicians and when adequate precautions are taken. It can be considered the last step before surgery in the conservative management of herniated lumbar discs.

Etiological theories and treatments for chronic back pain. I. Somatic models and interventions

This is the first part of an extended review of the etiology and treatment of chronic back pain (CBP). This paper will address the pathophysiology of CBP, the somatic conceptualizations that have been developed, and the treatment modalities that have been employed to alleviate the symptoms. The adequacy of the different models and treatments will be critically examined. The second paper in this set will examine psychological models and interventions. Common problems to both somatic and psychological approaches will be discussed at the close of the second paper.

Increased glycosaminoglycan excretion after chymopapain injection of intervertebral discs

The urinary excretion of glycosaminoglycans during the 24 hours after intradiscal injection of chymopapain was found to be greater than during the 24 hours before injection when comparison was made either on the basis of a complete 24-hour urine collection or by the use of a glycosaminoglycan/creatinine ratio. Each individual in a group of 14 patients showed this increase after injection. In contrast, no significant increase over the pre-injection levels was detected in serum glycosaminoglycans during the post-injection time periods for which blood samples were available.

Treatment of lumbo-ischialgias of different origins by intradiscal injection of chymopapain (discolysis). Analysis of literature and personal experiences

An analysis is given of a series of 25 patients suffering from lumboischialgic pain of different causes, which have been treated by discolysis. Literature reports are taken into consideration. As a result of analysis, the following statements seem justified: In no kind of lumbar disc prolapse are the results of discolysis superior to those of modern operative treatment. Discolysis results are indisputably worse in cases with the usual operative indication, which consists of neurological deficit and large disc prolapse. Favourable results by discolysis can be obtained in cases with disc protrusion or small prolapse, but these cases can mostly be cured also by consequent conservative treatment. Contraindications are marked neurological deficit, demonstration of a large disc prolapse by contrast methods, Verbiest's stenosis of the lumbar spinal canal, low back pain and ischialgia without possible proof of a disc protrusion, cases with low back pain as the main or only feature, spondylolisthesis. Disc prolapse recurrences after discolysis often occur about one month afterwards. Structural instability at this stage is likely. Therefore, as with postoperative treatment, it is advisable to avoid major physical stress for the first weeks after discolysis. Major complications after discolysis are possible, and have occurred. Because discolysis offers no real advantages but some shortcomings compared to conservative treatment for disc protrusions, and to operative treatment in real disc prolapses, its justification seems more than questionable.

Randomized clinical trials in the evaluation of surgical innovation

Randomized clinical trials are widely accepted as the standard for evaluation of therapeutic innovation in many fields of medicine. The three basic components of such trials (concurrent comparison, random allocation, and objective observation) are designed to control four forms of bias (chronology bias, susceptibility bias, compliance bias, and observation bias) that may interfere with the interpretation of the results of a study. Only 2% of the articles evaluating therapeutic maneuvers published in the Journal of Neurosurgery have attempted to use concurrent controls. Only one of 863 such articles met the criteria for a randomized clinical trial. Reasons for underutilization of such trials in neurosurgery are discussed and suggestions for their wider use are offered.

Prospective study of 100 lumbosacral discectomies

A prospective study of 100 patients undergoing discectomy was carried out. The neurological findings were documented preoperatively and at 1 month and 1 year postoperatively. The clinical and radiological data were analyzed with respect to significant associations. There were no complications. At a minimum of 1 year postoperatively, 63% of patients had complete relief of back pain and 73% had complete relief of leg pain. A discriminant analysis equation was derived which assessed the relative significance of factors as determinants of outcome. A method is given for estimating whether a patient will have a good or a poor outcome following the discectomy. Factors shown to be of significance should be recorded in prospective series to allow for comparison as to the efficacy of different methods of treatment. The results are better than those described for chemonucleolysis.

Double-blind evaluation of chemonucleolysis for herniated lumbar discs. Late results

Sixty-six patients with symptomatic herniated lumbar discs refractory to the usual conservative management were allocated at random into one of two treatment groups according to a double-blind protocol: 31 received chymopapain intradiscally (chemonucleolysis) and 35 received a placebo intradiscally. Symptoms remained significantly improved 1 year or more after injection for 55% of those treated with chymopapain and for 46% of those treated with placebo. The difference is not statistically significant. However, to discard chemonucleolysis on the basis of this one small clinical trial may be premature. Since continuing controversy has re-established a climate in which another double-blind study of chemonucleolysis is ethically feasible and scientifically desirable, we favor additional clinical trials under a tightly controlled protocol to help resolve the issue.