Transforaminal Epidural Steroid Injection For Lumbar Herniated Nucleus Pulposus: The Injection Versus Microdiscectomy Debate

1. BACKGROUND: THE BURDEN OF LUMBAR HERNIATED NUCLEUS PULPOSUS

Lumbar herniated nucleus pulposus (HNP), or lumbar herniated disc (Figure 1), resulting in back and leg pain traveling below the knee, sciatica, or radiculopathy, is a worldwide burden to society (Wilby et al., 2021). The condition affects an estimated 11% of patients presenting to their primary care provider worldwide (Jensen et al., 2019), with an annual prevalence estimated to be 2% (Hartvigsen et al., 2017). Generally, outcomes are favorable and 80% of patients improve with conservative care within 12–24 months (Wilby et al., 2021). However, given that patients affected by this condition are typically aged 40–50 years, there is a risk of loss of livelihood if it is not managed promptly.

Most patients experience an improvement in symptoms over time with either conservative treatment or surgery (Jensen et al., 2019) (Figure 2). In a five year follow-up of a Dutch randomized controlled trial (231 patients), 8% of patients showed no recovery and 23% reported ongoing symptoms that fluctuated over time (Lequin et al., 2013). Low back pain with pain radiating to the leg appears to be associated with increased pain, disability, poor quality of life, and increased use of health resources compared with low back pain alone (Jensen et al., 2019). Severity and duration of symptoms, radiological findings, or patient characteristics DO NOT consistently predict recovery of pain and function with conservative management, as per a systematic review (seven studies) (Ashworth et al., 2011).

2. MANAGEMENT OF LUMBAR HERNIATED DISC: THE LACK OF CONSENSUS ON A STEPWISE TREATMENT PROGRESSION

Treatment options have been considered by various international guidelines (Kreiner et al., 2014; Deyo and Mirza, 2016), but until recently no consensus existed for the role of transforaminal epidural steroid injection (TFESI) due to a scarcity of level I evidence. Generally, once analgesia and lifestyle-modifying treatments have failed, steroid nerve root injections and surgical microdiscectomy are recommended for severe persistent cases (Wilby et al., 2021). Stepwise care approaches based on treatment with non-opioids have been identified as likely to represent a more cost-effective approach than strategies involving direct referral for disc surgery (Kreiner et al., 2014); however, evidence for a stepwise treatment progression involving TFESI is scarce.

Prior to 2021, following various randomized trials comparing surgical treatments with non-surgical therapy (Atlas et al., 2017; Osterman et al., 2006), surgery was often deemed the most successful treatment option, leading to more than 10.000 discectomy procedures per year in the United Kingdom (UK) and 190.000 such procedures in the United States of America (USA) (Bernstein et al., 2017). The costs to the UK’s National Health Service (NHS) for microdiscectomy (requiring patients to be hospitalized for two nights, on average) are approximately ￡4500 compared with ￡700 for TFESI (Wilby et al., 2021).

Although treatment of radiculopathy with TFESI offers theoretical cost advantages and reduced risk compared with surgery, robust level I clinical data supporting its efficacy was scarce until recently (Wilby et al., 2021). Before 2021, the effectiveness of TFESI compared with surgery for lumbar herniated disc was uncertain (Lewis et al., 2011; Manson et al., 2013), leading to wide variation in management guidelines for this common condition (Wilby et al., 2021; Jensen et al., 2019).

3. THE "NERVES" STUDY: HIGH-QUALITY EVIDENCE FOR A STEPWISE TREATMENT FRAMEWORK FOR UNCOMPLICATED SCIATICA

In 2021, Wilby et al. published the NERVES study: a phase 3, multicenter (11 centers), open-label, randomized controlled trial and economic evaluation directly comparing surgical microdiscectomy with TFESI on a 1:1 allocation basis as initial invasive treatment for sciatica secondary to lumbar herniated disc.

NERVES was the first randomized trial to directly compare surgical microdiscectomy with TFESI on a 1:1 allocation basis as initial invasive treatment for the management of radicular pain secondary to lumbar herniated disc in patients with non-emergent presentation of sciatica with symptom duration of up to 12 months.

The authors found NO significant difference between TFESI and surgical microdiscectomy in clinical outcomes, concluding that surgery is unlikely to be a cost-effective alternative to TFESI. Complications of microdiscectomy were significant, offsetting any benefits of surgery as an early treatment, whereas only minor adverse events were observed with TFESI (Wilby et al., 2021) (Figure 3).

NERVES was the first high-quality randomized controlled trial reporting that the use of TFESI as the initial invasive treatment is similarly effective to surgical microdiscectomy at reducing pain and disability from sciatica with symptom duration between 6 weeks and 12 months (Wilby et al., 2021).

Given the safety of TFESI, along with the unlikely cost-effectiveness of surgical microdiscectomy as a first invasive treatment, the authors recommended that treating physicians strongly consider the use of TFESI as a stepwise invasive treatment for sciatica without neurological deficit of up to 12 months’ duration. The authors also concluded that surgery is still likely to be required for a considerable number of patients for whom TFESI might not be as effective.

4. REFERRAL FOR SURGICAL CONSULTATION: EMERGENT PRESENTATION AND THE LAW OF DIMINISHING RETURNS WITH EPIDURAL CORTICOSTEROID INJECTIONS

Urgent referral for surgical consultation SHOULD BE MADE in the setting of progressive neurologic deficits, saddle anesthesia, or bowel and/or bladder deficits if these issues are acute. Urgent referral to a spine surgeon SHOULD BE CONSIDERED if the patient has sensory or motor findings on physical examination but these deficits are stable (Schoenfeld et al., 2010).

If there is no effect after the first TFESI, there is still controversy with regards to whether the administration of additional injections is warranted (Kang et al., 2011). Currently, most experts agree that referral for surgical consultation SHOULD BE CONSIDERED if the patient does not improve following 1-2 TFESI.

Factors predicting successful outcome after surgical microdiscectomy include preoperative higher leg pain severity, better mental health status, younger age, increased preoperative physical activity, and severe preoperative low back pain. Interestingly, the presence of motor deficit, vertebral level or side of herniation, gender, and type I Modic changes were not found to affect postoperative outcomes (Amin et al., 2017).

INFORMATION FOR PATIENTS AND INDUSTRY PARTNERS

• All content and information in this article is for informational and educational purposes only, it DOES NOT constitute medical advice.
• If you are a patient looking for a medical appointment or a second opinion from our team at the Division of Pain Medicine at Hospital Clínic de Barcelona (Barcelona, Spain), please do so by following the link (in-person and telemedicine appointments are available in English, Portuguese and Spanish): Request Clinical Appointment.
• If you are a healthcare institution or industry partner looking for clinical research opportunities with our team or healthcare consultancy services, please do so by following the link: Request Healthcare Consultancy Services.
• If you are an industry partner looking to be featured on this Newsletter, please contact me directly through LinkedIn or to my e-mail: [email protected].