INTRODUCTION

Low back pain is a clinical condition of multifactorial etiopathogenesis, which includes: risk factors, lifestyle, occupational risk and inappropriate postures¹ , among others.

According to data from the Brazilian Institute of Geography and Statistics, back pain is the second most prevalent condition negatively related to health² , affecting about 80% of adults throughout their lives³ .

Low back pain triggers a high socioeconomic impact, especially in the economically active population⁴ , as it is associated with frequent absenteeism and reduced quality of life⁵ . In the United States of America, the costs associated with low back pain are estimated at around 2 million dollars⁶ , in the United Kingdom it is approximately 1.6 million euros, and worldwide the economic impact is between 6.6 million and 12.3 million euros⁷ .

Built by the interaction between the predisposing biopsychosocial components, a multidisciplinary therapeutic proposition⁸ is suggested, paying special attention to age, gender, body mass index, underlying diseases, labor and socioeconomic conditions, in addition to muscle imbalances⁹ . It is important to identify the level of pathological contribution of the lumbar paraspinal muscles, necessary for carrying out movement and biomechanical stabilization, both locally and in the body¹⁰ . Patients with Chronic Low Back Pain (CLBP) have reduced quality of life, reduced muscle strength, as well as constant pain¹¹ .

Due to its location in the central region of the human body, it is postulated that the lumbar spine is of vital importance for body biomechanics, as it transmits mechanical forces generated by musculotendinous components, while absorbing and dissipating mechanical impacts through the intervertebral discs, mainly during the spinal load that is distributed vertically and laterally to the endplates, in order to allow the stable mobility of the spine¹² . Through degeneration of the intervertebral disc, progressive instability of the affected region and other regions of the spine is observed, predominantly between the fourth and fifth lumbar vertebrae and the first sacral vertebrae¹³ .

With little clarified etiology, the progressiveness of the degeneration can be modified by the way of life, discopathies can be developed by mechanical, environmental and genetic factors^{14 , 15} . Dehydrated intervertebral discs become fibrocartilaginous decreasing their stability and triggering a harmful positive feedback mechanism that further promotes intervertebral disc disease¹⁶ .

The clinical implications of discopathies in symptomatic patients consist of bouts of chronic low back pain, weakness in the lower limbs, tingling and numbness of the extremities and increased pain depending on the movement performed, with impairment of the individual’s quality of life, which can be treated in invasive or non-invasive¹⁷ .

Physiotherapy is among the non-invasive non-pharmacological methods, which include a range of techniques for rehabilitation, improvement of quality of life and reduction of symptoms¹⁸ . However, in persistent low back pain, treatment involves a range of non-surgical procedures, in addition to surgical ones, such as disc decompression for neuropathic pain through Percutaneous Lumbar Discectomy (PLD), among others⁸ .

PLD is a minimally invasive surgery that offers the least aggression to the body, thanks to advanced technological resources¹⁹ , commonly indicated in cases of disc herniation with clinically intractable pain, for a minimum period of three months, associated or not with minimal neurological deficit, characterized by mild loss of muscle strength and/or changes in surface sensitivity^{20 , 21} . Except in cases of extruded hernia, root canal narrowing, spondylolisthesis, advanced disc degenerative process with air in the disc or recent conventional surgery at the same level²⁰ .

Given the context described above, the present study was carried out with the general objective of evaluating the scientific evidence related to clinical outcomes in patients with lumbar disc herniation submitted to percutaneous lumbar discectomy. The objective was also to gather data on the safety of this minimally invasive surgical intervention.

METHOD

This is a systematic review, developed based on some of the recommendations proposed in the instrument called PRISMA (Main Items for Reporting Systematic Reviews and Meta-analyses)²² , motivated from the guiding clinical question, elaborated based on the PICOD strategy, which represents the acronym for Patient, Intervention, Comparison, Outcomes and Design²³ . These recommendations are considered essential for the elaboration of a consistent systematic review of clinical studies^{24 - 27} .

Based on the state of the art described in the introduction of the present study, the following clinical question was formulated: What is the scientific evidence on the clinical outcomes subsequent to the surgical procedure of percutaneous lumbar discectomy, in patients with Lumbar Disc Herniation? From which, the following terms were extracted and identified as scientific descriptors with the MeSH Terms operating system (https://www.ncbi.nlm.nih.gov/mesh/): “percutaneous”, “discectomy”, “percutaneous” , “lumbar vertebrae”, “humans”. For reasons of contextual proximity, the following descriptors were also listed: “automated”, “diskectomy”, “nucleotomy”, microdiscectomy”, “endoscopic”, and “laser”, with the aim of establishing an adequate Boolean search strategy with the database: MEDLINE/PubMed (https://www.ncbi.nlm.nih.gov/pubmed/), SPORTDiscus – EBSCO (https://web-p-ebscohost.ez43.periodicos.capes.gov.br/ ) and SCOPUS (https://www-scopus.ez43.periodicos.capes.gov.br/). Which was performed on 06/21/2022, as follows: ((automated AND/OR (percutaneous AND ((discectomy OR diskectomy) OR nucleotomy)) AND “lumbar vertebrae” AND humans) NOT (microdiscectomy OR endoscopic OR laser)).

The election of inclusion and exclusion criteria was carried out according to the principles proposed in the specialized literature^{27 - 29} . As eligibility criteria, we chose to include clinical trials in patients with lumbar disc herniation who underwent percutaneous lumbar discectomy, without language or publication date restrictions. As exclusion criteria, among the included documents, we opted for those studies carried out in children, in patients with structural locomotion restrictions, articles without access in full or, with contents not related to the objectives proposed in the present study.

All documents found were gathered in the virtual environment of the application Rayyan QCRI - Qatar Computing Research Institute (https://rayyan.qcri.org/welcome)³⁰ , for the identification and elimination of all existing duplicates between the documents listed in the different databases. of data. Then, the 1st stage of the assessment of eligibility for inclusion or exclusion of each of the related documents was carried out in pairs between three reviewers, members of the research team. At this stage, after reading the article, each evaluator indicated in a spreadsheet one of the three options (included, maybe, or excluded), and these individual options were transferred to a general spreadsheet, for the purpose of analyzing the level of agreement between the evaluators, followed by the definition of the eligibility of each study through the absolute agreement between the options indicated by each evaluator. In those situations of divergence between the indicated options or of doubt (maybe), the definition was consensual, in the midst of a collective evaluation of the study in question, between the evaluators and the researcher responsible for the present study, as recommended in the literature²⁹ .

Quantitative data relating to the document identification stages in the different databases up to the exclusion stage, the screening process, eligibility, inclusion and exclusion of scientific documents to be analyzed, are indicated in the flowchart ( figure 1 ), located in the results section.

Figure 1 : Flowchart of the stages of the process of eligibility of studies for analysis 

As proposed in the literature²⁸ , prior to data extraction, the present study was registered (registration code: CRD42022370811) in the database of systematic review protocols called PROSPERO (https://www.crd.york.ac. uk/prospero/), with the objectives of: avoiding duplication of studies on the chosen topic, providing full transparency on the preparation method, as well as ratifying and/or improving the methodological quality of the study under development through the opinion issued by the respective team of evaluators.

Data related to primary or secondary variables were selected and extracted independently between examiners, as previously described, including in situations of disagreement about certain data(s)^{26 , 29} .

The Grade or Strength of Recommendation and the Level of Evidence were evaluated, also in pairs, based on the descriptors of the Oxford and Grade^{31 - 33} scales.

Although ethical approval is not required in this type of study, the ethical character of the present study was ensured by strict compliance with the commitments assumed with the registration system, as well as the guarantee of the veracity of each stage and, due consideration of the task carried out by the different authors who are members of the research team during its construction process.

RESULTS

All data related to the eligibility process of scientific documents are indicated in the flowchart ( Figure 1 ), in which it is observed that among the 44 articles identified in the aforementioned data platforms, 73% were excluded based on the exclusion criteria pre-established, and the remaining 27% became the constituent components of the sample space of the present systematic review study.

Regarding the literary aspects of the articles included ( table 1 ), it is noted that among the documents published in the period from 1989 to 2011, 4 (33%) are authored affiliated with China, 3 (25%) with France, 2 ( 17%) to Turkey, while the other remaining 25% (3) are equally associated with Korea, USA and Italy.

When evaluating the outcomes described in the different studies included in this SR ( Table 2 ), we observed a consensus that PLD is a safe surgical procedure, especially when monitored by CT, using or not the TENG instrument. It can also be considered effective in reducing pain and improving function in around 40 to 70% of patients, especially in those with small disc herniations located in the posteroforaminal or extraforaminal region, although the results are also favorable in cases of posteromedian hernias. Such effectiveness of this surgical procedure, considered minimally invasive, can be attributed to the fact that it is possible to directly visualize the neuroforamen, preserve the facet joint and prevent postoperative instability.

Based on the data related to the levels and quality of evidence ( Table 3 ), we observed that, according to the Oxford Scale instrument, all studies have quality and level of evidence IIB, as they are prospective clinical trials of individuals with herniated discs with care physicians received (outcomes research), among which 9 have strength of recommendation A (good evidence to support a recommendation for use, and the other 3 were considered B (moderate evidence to support a recommendation for use). evidence based on the Grade Scale instrument, we observed that among the 12 included studies, 9 were evaluated with a HIGH level of evidence because there is a strong confidence that the true effect is close to that estimated and that it is unlikely that additional work will change the confidence in estimating the effect. The other 3 remaining studies were evaluated with a MODERATE level of evidence, by demonstrating r moderate confidence in the estimated effect, in such a way that future works may modify the confidence in the effect estimate, and may even modify the estimate.

We emphasize the fact that, when analyzing the data on levels of evidence and strength of recommendation ( Table 3 ), we observed that all studies evaluated as a HIGH level of evidence based on the Grade Scale, were also evaluated with high strength of recommendation both by the Grade Scale and the Oxford Scale. As occurred in the 3 studies considered to have a MODERATE and MODERATE level of evidence or WEAK recommendation strength, according to the assessment based on the instruments, respectively, Oxford Scale and Grade Scale.

DISCUSSION

Open microdiscectomy has always been a surgical strategy commonly used in the treatment of herniated discs with good clinical results, despite the damage caused to the facet joints and subsequent lumbar instability³⁴ . At the same time, percutaneous lumbar discectomy (PLD), also used to treat discopathies, is a minimally invasive surgical procedure that has been technologically improved and widely used over time, with the aim of reducing interdiscal pressure through puncture and aspiration. nucleus pulposus, followed by reduced pressure on the nerve root and associated with reduced pain^{34 - 36} . This surgical procedure is very useful for controlling lumbosacral pain in cases of disc herniation unresponsive to epidural injections of steroidal drugs³⁷ , especially in cases where there is no migration of herniated discs and the presence of unilateral disc herniation³⁸ . As observed in some studies^{39 - 50} , in which a relevant clinical improvement of patients was pointed out, especially in relation to pain and also to body functionality.

In addition, PLD provides a short intervention time, a quick recovery of the patient and a short intra-hospital stay, and reduced damage to local musculoskeletal structures^{20 , 34 , 36} , when compared to open surgery. Statements that corroborate the data reported in the present study, which highlight the greater effectiveness of PLD compared to open surgery⁴⁰ , probably because it allows direct visualization of the neuroforamen associated with preservation of the facet joint and prevention of postoperative instability⁴³ .

It is observed that PLD applied to patients with low back pain unresponsive to medical therapy is a safe and efficient procedure in reducing pain and improving body function⁵¹ . Like the data observed in the different articles included in the present review study, in which it was also pointed out that the monitoring of PLD through computed tomography increases the success rate in the treatment of discopathies⁴⁷ , as well as the use of the Teng instrument during the referred procedure⁴⁸ , in addition to the proposition that: the safety and efficacy of PLD in the treatment of disc herniations in L5-S1 increases if it is preceded by a complete bowel preparation⁴⁹ .

It should be noted that, due to the considerable terminological variety related to the different procedural surgical technologies for disc herniations, a rigorous structuring of the Boolean search strategy for scientific documents is necessary for the correct elaboration of a systematic review related to the surgical treatment of discopathies . Therefore, in the present study, the Boolean search was structured considering the various scientific descriptors associated with the central theme, in order to maximize the direction of the research towards the desired and necessary literary universe. However, it is possible that other articles related to the scope of this study can be identified in other databases using this same search strategy. This fact is a possible weak point of the present review study.

CONCLUSION

Based on the qualitative aspects of the set of evidence gathered in this systematic review study, we conclude that Percutaneous Lumbar Discectomy can be considered a minimally invasive surgical procedure with high safety and effectiveness in the treatment of patients with lumbar hernia, associated with a satisfactory level of reduction of pain and improvement of body functionality.