The spinal column is composed of a series of connecting bones (i.e., vertebrae) that protect the nerves that exit the brain and travel down into the body. The vertebrae are divided into several segments (cervical, thoracic, lumbar, and sacral), with individual vertebrae separated by intervertebral discs. These intervertebral discs act as shock absorbers for the spinal column. The outer portion of the disc is known as the annulus fibrosus and is composed of collagen; the inner portion of the disc is known as the nucleus pulposus and is composed of a soft gelatinous material. When this soft gelatinous material herniates through the outer portion of the disc into the spinal canal, it may cause pain in the back or sciatica (i.e., numbness, pain, weakness, or tingling in the leg).
Herniation of the disc can be caused by strain, trauma, or disc degeneration and usually occurs in the lumbar region. This condition may be conservatively treated with bedrest, medication (e.g., analgesics for pain control, anti-inflammatories to reduce swelling, muscle relaxants), and/or physical therapy. Studies indicate that without surgery, individuals with herniated discs may improve 80 percent to 90 percent of the time. For individuals who do not respond to conservative treatment, surgical treatments may be explored, such as standard discectomy or microdiscectomy. Additionally, percutaneous discectomy has been explored as a potential surgical treatment option and is theorized to result in decreased morbidity and less potential for perineural scarring and intraoperative blood loss or infections.
Percutaneous discectomy (i.e., percutaneous disc decompression, percutaneous nucleotomy) is a surgical procedure used to treat herniated lumbar, thoracic, and cervical discs. It can be performed manually, using an automated device, or by laser. Performed through a needle inserted into the skin, in which portions of the intervertebral disc are accessed and removed through a cannula (i.e., surgical tube), the procedure is intended to relieve pressure on the nerves surrounding the disc. When percutaneous discectomy is performed manually, cutting forceps are used to remove the nuclear material from within the disc annulus. During automated percutaneous discectomy, a probe is used to excise small pieces of the nucleus by aspiration. Laser discectomy involves the placement of a laser within the nucleus, which is then activated to ablate the disc material. The Stryker DeKompressor® Percutaneous Discectomy Probe (Stryker) and the Nucleotome® (Clarus Medical) are examples of percutaneous discectomy devices that received clearance from the US Food and Drug Administration (FDA) for use in aspiration of disc material during percutaneous discectomies in the lumbar, thoracic, and cervical regions of the spine. Percutaneous endoscopic discectomy is also being investigated, which involves the percutaneous placement of a working channel under image guidance, followed by visualization of the working space and instruments through an endoscope, and aspiration of disc material.
PEER-REVIEWED LITERATURE
In a Cochrane review, Gibson and Waddell (2007) evaluated the effects of various surgical interventions for the treatment of lumbar disc prolapse (i.e., slipped disc, herniated disc). The authors noted that while disc prolapse accounts for only five percent of low back disorders, it is one of the most common reasons for surgery. Forty randomized controlled trials (RCTs) and two additional studies were identified. The authors noted that many of the early trials described chemonucleolysis (i.e., dissolving the bulging disc with the use of an injected enzyme) as the primary intervention, whereas the majority of the later studies compared different techniques of discectomy. Four trials were identified that compared discectomy with conservative management. Specific to percutaneous discectomy, the authors concluded that there was insufficient evidence to draw firm conclusions. The study is limited in its heterogeneous population and surgical interventions.
In a literature review, Nezer and Hermoni (2007) evaluated the current state of evidence for percutaneous discectomy in treating low back pain. In addition to RCTs and systematic reviews, the authors assessed guidelines from the National Institute for Health and Care Excellence (NICE). The authors concluded that the results from these studies and guidelines indicate that until better scientific evidence is available, automated percutaneous discectomy and laser discectomy should be regarded as research techniques.
In a literature review, Goupille et al. (2007) evaluated the current state of evidence for percutaneous laser disc decompression in treating lumbar disc herniation (LDH). The authors noted that the concept of laser disc decompression was based on the percutaneous introduction of an optical fiber into the intervertebral disc. The administered laser energy would allow for the vaporization of portions of the nucleus pulposus, which may reduce intradiscal pressure and relieve radicular pain. The authors note that there is no consensus on the type of laser to use, the wavelength, duration of application, or appropriate energy applied. Study methodology and conclusions are questionable, and no controlled studies were published at the time of the literature review. The authors concluded that although the concept of laser disc decompression is appealing, the treatment cannot be considered effective for disc herniation–associated radiculopathy, refractory to conservative treatment.
In a retrospective study, Liu et al. (2010) evaluated the long-term outcomes of individuals with LDH who were treated with percutaneous lumbar discectomy (PLD) or microendoscopic discectomy (MED). A total of 129 individuals were treated with PLD and 101 individuals underwent MED. Ultimately, 80.62 percent of the PLD group (n=104) and 81.19 percent of the MED group (n=82) were eligible for analysis and followed for a mean of 6.64 ± 0.67 years and 6.42 ± 0.51 years, respectively. Outcome measurements included Oswestry Disability Index (ODI; higher scores indicate increased disability) and a 36-Item Short-Form Health Survey (SF-36), a standardized questionnaire used to measure an individual's overall subjective health status (higher scores indicate better overall health). The authors reported that 75.96 percent of the PLD group and 84.15 percent of the MED group achieved excellent or good results, representing a statistically significant difference (P=0.0402). The average ODI scores and minimal disability were 6.97 percent and 71.15 percent in the PLD group and 4.89 and 79.27 percent in the MED group, respectively. The authors concluded that both PLD and MED show an acceptable long-term efficacy for the treatment of LDH, but admitted that compared with MED individuals, long-term satisfaction is lower in the PLD individuals. Additionally, individuals in the MED group had a statistically significantly higher rate of excellent or good results when compared with the PLD group. The study is limited in its small sample size and retrospective study design. Outcome measurements were also measured by both telephone and self-administered questionnaires, which may hinder the internal validity of the study.
In 2010, Teli et al. reported on an RCT comparing endoscopic discectomy to microdiscectomy or open discectomy in 240 individuals with posterior LDH. Most herniations (60 percent) were extrusions. The average surgical time was longer in the endoscopic group (56 minutes) than in the micro- or open discectomy groups (43 minutes and 36 minutes, respectively). Follow-up assessments were performed at 6, 12, and 24 months by an independent investigator; 212 (91 percent) individuals completed the 24-month evaluation. Intention-to-treat analysis showed no significant differences in the outcome variables (visual analog scale [VAS], ODI, and SF-36 scores). The endoscopic procedure led to more dural tears (8.7 percent vs 2.7 percent or 3 percent), root injuries (3 percent vs. 0 percent or 0 percent), and recurrent herniations (11.4 percent vs. 4.2 percent or 3 percent) than the microdiscectomy or open approaches, respectively, although differences were not statistically significant.
In a retrospective study, Tzaan (2011) evaluated the safety and effectiveness of anterior percutaneous endoscopic cervical discectomy (APECD) for the treatment of cervical intervertebral disc herniation. A total of 107 consecutive individuals with clinically symptomatic cervical disc herniation were initially enrolled. Of these individuals, 80 percent (n=86) were followed for at least 12 months, for a mean of 22.4 months (12–60). Visual analog scale (VAS) and neck disability index (NDI) scores had a statistically significant improvement after APECD (P<0.001). Excellent and good outcomes were achieved in 34 percent (n=29) and 57 percent (n=49) of the individuals, respectively. Two individuals experienced operation-related complications (carotid artery injury and postoperative headaches). The authors concluded that APECD is a minimally invasive method to treat cervical hernias. However, they cautioned that it carries the risk of major complications and that careful individual selection and the use of meticulous surgical techniques was important. The study is limited in its small sample size, mid-term follow-up period, retrospective design, and lack of a comparative control group.
Garg et al. (2011) reported on a trial randomly assigning 112 individuals with a single-level disc herniation to microendoscopic lumbar discectomy or to open discectomy. The method of randomization and whether individuals and assessors were blinded were not reported. Surgical time was significantly longer in the endoscopic group (84 minutes vs. 56 minutes), whereas blood loss (41 mL vs. 306 mL) and hospital length of stay (3 days vs. 12 days) were reduced. ODI scores were similar at baseline (endoscopic, 25.78 vs. open discectomy, 21.02) and all follow-up visits through 1 year postoperatively (endoscopic; 1.75 vs. open discectomy 2.14).
In a prospective RCT, Chitagran et al. (2012) evaluated the effectiveness of percutaneous nucleoplasty compared with conservative treatment in individuals with radicular or axial low back pain, secondary to contained herniated discs. Sixty-four individuals were randomly assigned in a 1:1 ratio. Individuals were evaluated at 1, 3, 6, and 12 months postoperatively. Outcome measurements included VAS scores and pre- and postnucleoplasty MRI at 3 months to evaluate the decrease of bulging discs. Reported pain and medication use had a statistically significant decrease and functional status had a statistically significant increase at 1, 3, 6, and 12 months postnucleoplasty (P≤0.001). The bulging disc was statistically significantly decreased at 3 months following nucleoplasty. The authors concluded that percutaneous nucleoplasty was an effective procedure for individuals presenting with discogenic back and/or radicular pain, refractory to conservative treatment. The study is limited in its small sample size and short-term follow-up period. Additionally, whereas comparisons can be made to conservative treatment, the effectiveness of percutaneous discectomy cannot be generalized in comparisons with more established surgical treatment options such as standard discectomy.
In a retrospective comparative study, Adam et al. (2013) evaluated the effectiveness of percutaneous nucleoplasty compared with open discectomy in individuals with degenerative disc disease and lumbar disc protrusions. Two cohorts of 80 individuals each were followed for up to 1 year. Individuals in the percutaneous nucleoplasty group had radicular symptoms caused by herniation, with a herniated disc less than 6 mm, refractory to conservative treatment. Individuals in the open discectomy group had a herniated disc greater than 6 mm. Outcome measurements included a Rolland-Morris disability questionnaire (higher scores indicate increased disability) and mean VAS scores preoperatively and at 3, 6, and 12 months after the respective procedure. VAS scores decreased from a preoperative score of 7.9 to 2.2 in the percutaneous nucleoplasty group and a preoperative score of 8 to 1.8 in the open discectomy group at 1-year follow-up. Rolland-Morris disability scores improved in 60 percent of the individuals who underwent percutaneous nucleoplasty and 78 percent of the individuals who underwent open discectomy. The authors concluded that percutaneous nucleoplasty was a safe and effective method to treat individuals with lumbar disc protrusion. The study is limited in its small sample size, short-term follow-up period, and retrospective study design. Additionally, results were only presented with frequency analysis. Despite the comparative design, any attempts at statistical significance testing were not presented. The authors also admitted there were issues affecting the study’s internal validity, including patient compensation and potential study bias.
Eight-year follow-up from a quasi-RCT assessing endoscopic lumbar discectomy and open discectomy was reported by Hussein et al. (2014). The trial included 185 individuals with a large uncontained LDH. Surgery times were similar for both groups. Postsurgical mean hospital length of surgery was 10.4 hours for the endoscopic group and 82.38 hours (P<0.05) for the open group. Mean time to return to work/normal activities after endoscopic surgery (8.5 days) was significantly shorter than after open surgery (31.4 days; P<0.05). The percentages of adverse events were similar between groups, and 8.1 percent of individuals in each group required reoperation during the follow-up. Improvements in leg pain, back pain, and ODI scores (1.05, 1.43, 21.5 percent, respectively) persisted at 8 years in the endoscopic group, but deteriorated for back pain (7.53) and ODI scores (59.6 percent) in the open group.
A number of observational studies have also assessed the learning curve (Lee and Lee, 2008; Wang et al., 2011; Tenenbaum et al., 2011) and the need for longer follow-up for endoscopic discectomy (Casal-Moro et al., 2011; Wang et al., 2012; Choi et al., 2015). The largest and longest follow-up to date has been reported by Choi et al. (2015), who examined 10,228 individuals at their institution who had percutaneous endoscopic lumbar discectomy (PELD) over a 12-year period. The authors found that 4.3 percent of cases required reoperation in the first 6 weeks due to incomplete removal of herniated discs (2.8 percent), recurrence (0.8 percent), persistent pain (0.4 percent), and approach-related pain (0.2 percent).
In 2016, Gotecha et al. published a prospective study on the use of transforaminal PELD for the treatment of LDH. Efficacy and limitations of the procedure were studied on 120 individuals with LDH. Using McNab criteria, 89 percent achieved excellent (no pain or restrictions) or good (occasional back/leg pain) status at 6 months of follow-up. The authors noted that a limitation of the procedure is that, during surgery on individuals with L5 through S1 LDH, the iliac crest may interfere with the angle necessary to perform successful discectomy.
A 2016 systematic review and meta-analysis published by Li et al. compared full endoscopic discectomy (FED) with traditional discectomy surgery. A literature search was conducted in January 2015 and resulted in the inclusion of four RCTs and two non-RCTs. FED for herniation (both cervical and lumbar) was favorable compared with traditional discectomy in surgery duration, blood loss, length of stay, and return to work days. Clinical outcomes were comparable between FED and traditional discectomy.
A 2016 meta-analysis identified nine RCTs (total N=1092 individuals) through August 2014 that compared endoscopic to open discectomy for LDH. Endoscopic discectomy resulted in clinical outcomes similar to open discectomy, but had significantly greater individual satisfaction, lower intraoperative blood loss, and shorter hospital length of stay.
In 2017, Gibson et al. published an RCT comparing transforaminal endoscopic discectomy (TED) with microdiscectomy. Individuals with single-level lumbar prolapse and radiculopathy were randomly assigned to TED under conscious sedation (n=70) or to microdiscectomy under general anesthesia (n=70). Both procedures resulted in comparable improvements in outcomes (ODI scores, VAS back pain, VAS leg pain, SF-36 scores) at 3 months, 1 year, and 2 years compared with baseline.
In 2017, Phan et al. published a systematic review and meta-analysis comparing FED and MED with open discectomy for the treatment of LDH. A database search through February 2016 identified 23 studies for inclusion. FED was favorable compared with open discectomy in surgery duration, hospital length of stay, and blood loss. MED was favorable compared with open discectomy in terms of length of stay and blood loss. Both endoscopic procedures were comparable to open discectomy, as measured on a VAS for leg pain and ODI score. In terms of the individual's satisfaction, FED was more favorable than open discectomy, and MED was comparable to open discectomy.
A systematic review and meta-analysis was performed in 2021 by Gadjradj et al. to compare the effectiveness of percutaneous transforaminal endoscopic discectomy (PTED) with open microdiscectomy (OM) in the treatment of LDH. The authors concluded there is moderate quality evidence suggesting there was no difference in leg pain or functional status at intermediate- and long-term follow-up between PTED and OM in the treatment of LDH. High-quality studies reporting on clinical outcomes and cost-effectiveness in the long term are lacking.
In 2021, Bai et al. performed a meta-analysis that investigated whether PELD had a superior effect than other surgeries in the treatment of individuals with LDH. Fourteen studies involving 2528 individuals were included in the meta-analysis. The authors concluded that PELD was associated with better effects and similar complications as other LDH surgeries; however, the procedure also resulted in a higher re-occurrence rate requiring further large-scale randomized trials.
PRACTICE GUIDELINES AND POSITION STATEMENTS
In a 2005 guideline, NICE addressed automated percutaneous mechanical lumbar discectomy. They noted that although current evidence suggests that there may be no major safety concerns associated with the procedure, there was limited evidence of effectiveness based on uncontrolled case series. The population for these studies included a heterogeneous group of individuals. Additionally, small RCTs showed conflicting results, which represents an uncertainty regarding the effectiveness of the procedure.
In a 2007 guideline, the American Society of Interventional Pain Physicians (ASIPP) addressed percutaneous disc decompression. This evidence-based practice guideline included literature searches, systematic reviews, consensus evaluations, blinded peer review, and open forum presentations. Based on the current state of evidence and clinical input, the ASIPP determined that percutaneous disc decompression remains controversial. Among the various techniques utilized for the procedure, the evidence was moderate in the short-term and limited in the long-term for procedures that utilize the Nucleotome® and DeKompressor® devices, including automated percutaneous lumbar discectomy percutaneous laser discectomy.
In a 2009 guideline, NICE addressed percutaneous endoscopic laser lumbar discectomy. They noted that the current evidence on the safety and effectiveness of the procedure was inadequate in quantity and quality. Adverse events included thecal sac injury with cerebrospinal fluid leakage, transient dysesthesia (i.e., abnormal sensation), and sympathetic mediated pain (i.e., pain related to involuntary body functions).
The American Society of Pain and Neuroscience (ASPN) in 2022 published clinical guidance for interventional treatments for low back pain. The guideline states that discectomy procedures (such as percutaneous and endoscopic disc procedures) have favorable safety and efficacy profiles for the treatment of lumbar disc herniation with persistent radicular symptoms; however, the guideline stated that further research is needed to evaluate complication rates in order for these procedures to supplant classic open microdiscectomy.
SUMMARY
There is limited literature indicating that percutaneous discectomy may yield symptom relief in a select group of individuals compared to conservative management or conventional surgical approaches (e.g., standard discectomy). The current available peer-reviewed literature describes heterogeneous populations and treatment modalities. Guidelines from various medical societies indicate that the current state of evidence is insufficient and has not yet provided clinical evidence that percutaneous discectomy is as safe and effective as conservative management or traditional surgical treatments. Therefore, the current available peer-reviewed literature does not support the use of percutaneous discectomy in lumbar, thoracic, and cervical areas of the spine.
For individuals who have herniated intervertebral disc(s) who receive percutaneous endoscopic discectomy, the evidence includes a number of RCTs and systematic reviews of RCTs. Relevant outcomes are symptoms, functional outcomes, quality of life, and treatment-related morbidity. Many of the RCTs were conducted at a single center in Europe. Some trials have reported outcomes at least as good as traditional approaches with an open incision, while one RCT from a different center in Europe reported a trend toward increased complications and reherniations using an endoscopic approach. There are few reports from the United States. The evidence is insufficient to determine the effects of this technology on health outcomes.
