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Don’t waste your time for a fascial block. Nicky Van Der Leeden MD1, Liesbeth Brullot MD1, Steve Coppens MD, PhD1,2 1 University Hospitals of Leuven, Department of Anesthesiology, Herestraat 49, B-3000, Leuven, Belgium 2 University of Leuven, Biomedical Sciences Group, Department of Cardiovascular Sciences, KU Leuven, B-3000, Leuven, Belgium Background Fascial plane blocks have emerged as an alternative to neuraxial techniques for postoperative analgesia in the context of laparoscopic and robotic surgeries, where reduced tissue trauma diminishes the need for deep regional interventions. These blocks aim to provide segmental analgesia by depositing local anesthetic in interfascial compartments under ultrasound guidance. Discussion This article critically examines the clinical evolution, anatomical rationale, and safety profile of these blocks. While initially celebrated for their simplicity and low invasiveness, the literature surrounding the fascial plane blocks is characterized by inconsistent terminology, poor methodological rigor, and limited comparative evidence. The blocks often fail to deliver reliable visceral analgesia, and their clinical efficacy is hampered by anatomical variability and unpredictable spread. Furthermore, systemic absorption of local anesthetics may contribute to analgesia more than previously understood, particularly in postoperative and obstetric populations where pharmacokinetics are altered. Although generally perceived as safe, they are not without risk—deep variants may endanger vascular structures, and high-volume injections raise concerns of local anesthetic systemic toxicity. Comparative trials with neuraxial or opioid-based analgesia remain scarce and underpowered, limiting their role in evidence-based enhanced recovery pathways. Clinically, the benefit of plane blocks appears transient and inconsistent, with the most appropriate use potentially limited to rescue scenarios in pain-sensitive patients or postoperative recovery units. Conclusions Fascial plane blocks are not a panacea for perioperative pain. Their utility lies in selective, patient-tailored rescue use rather than routine inclusion in enhanced recovery protocols. Future research must prioritize rigorous comparison with established techniques, improved anatomical understanding, and stratified approaches based on individual pain phenotypes. Keywords: Fascial plane blocks, regional anesthesia, postoperative pain, local anesthetic systemic toxicity, enhanced recovery after surgery Introduction The advent of laparoscopic and robotic surgery has fundamentally altered perioperative care, especially in the realm of postoperative analgesia. Precision-based dissections and smaller incisions have drastically reduced tissue trauma and inflammatory responses, challenging long-standing strategies built around more invasive pain management modalities. Techniques such as thoracic epidural analgesia and even paravertebral blocks once heralded for their ability to attenuate nociceptive transmission and the surgical stress response, now appear disproportionate in risk relative to the needs of many current surgical procedures. 1 Despite its efficacy EA has been associated with a range of adverse events—spinal hematoma, epidural abscess, significant hypotension, and catheter malfunction among them. In parallel with the diminishing need for its use, a new category of regional blocks has emerged: fascial plane blocks (FPBs). These ultrasound-guided techniques aim to provide segmental analgesia by depositing local anesthetic (LA) solutions in anatomically defined fascial planes.2 Evolution of a Technique FPBs initially gained attention as an elegant and intuitive solution to the gap between neuraxial and peripheral nerve blocks. By targeting tissue planes where nerves course within or between muscles, these blocks promised expansive dermatomal coverage with minimal invasiveness. Aided by advancements in ultrasonography, their clinical implementation grew rapidly.3 4 However, this growth was accompanied by an oversaturation of literature dominated by descriptive studies, case series, and low-powered trials.5–7 Novelty often took precedence over validation, and anatomical variations of existing approaches were frequently rebranded under new names. As a result, consistency in nomenclature and methodological rigor became casualties of the movement. The fact that a Delphi consensus process was required simply to clarify the names and anatomical logic behind these blocks reveals a deeper, systemic issue. Rather than addressing the clinical effectiveness of these techniques, the consensus process highlighted the extent of confusion—even within the expert panel itself, of which I was a member—regarding the fundamental anatomical identity of many of these blocks.8 Clinical Context and Shifting Utility Initial applications of FPBs, such as the transversus abdominis plane (TAP) block, were met with optimism in gynecological, urological, and general surgery. Yet as operative techniques became increasingly refined, the significance of postoperative somatic pain began to wane. Smaller ports, reduced insufflation pressures, and more delicate instrument manipulation have made the contribution of abdominal wall pain less clinically relevant. The PAROS trial, published in 2021, clearly demonstrated that lowering intra-abdominal insufflation pressure significantly reduces postoperative pain, highlighting the role of surgical technique in modulating pain outcomes.9 In contrast, no fascial plane block to date has convincingly demonstrated visceral analgesia.10 While theoretical models suggest that blocks like the erector spinae plane block (ESPB) or quadratus lumborum (QLB) might achieve paravertebral spread, this has not been consistently confirmed—even in cadaveric studies, which themselves carry significant methodological limitations.11 Moreover, growing evidence suggests that earlier studies on FPBs may have overestimated their benefits due to selective publication. Negative trials often faced delays or remained unpublished altogether. As contemporary investigations re-evaluated these techniques under newer surgical protocols, effect sizes appeared smaller, and reproducibility became an issue. Biological Complexity of Fascial Compartments The anatomical and histological understanding of fascia has evolved substantially in recent years. Contrary to early assumptions that fascial planes serve as open conduits for LA distribution, contemporary research has shown them to be dense, dynamic tissues filled with a matrix of collagen, elastin, and hyaluronan.7 These structures are neither uniform nor passive. Fasciacytes contribute to lubrication and movement, while architectural variations—such as septa, interconnections, and fusion zones—render LA distribution unpredictable. The variability in fascial thickness and nerve path trajectories between individuals further complicates the expected outcomes of FPBs. Due to this anatomical variability and the presence of often-overlooked structural barriers, fascial plane blocks yield inconsistent and unpredictable analgesic outcomes. Given the clinical imperative to deliver reliable, effective, and low-risk perioperative pain management, their use should be approached with caution. At present, fascial plane blocks should not be considered a first-line analgesic strategy in surgical pathways where more established and reproducible techniques are available. Actually the whole current nomenclature surrounding so-called fascial plane blocks is conceptually misleading. It encompasses a heterogeneous group of techniques—many of which are proxy blocks—without consistent interfascial injection. In reality, few of these blocks involve true deposition of local anesthetic between distinct fascial layers. For example, the rectus sheath block is anatomically a compartment block, targeting the space enclosed within the sheath rather than any fascial interface per se. Although the ESPB is commonly classified among fascial plane blocks, its anatomical target does not conform to the classical definition of a true fascial plane. In standard technique, local anesthetic is deposited between the erector spinae muscle and the underlying transverse processes—a potential space that lacks a well-defined, named fascial boundary. Unlike established fascial plane blocks such as the TAP, which involves injection between distinct fascial layers, the ESPB relies on myofascial spread rather than interfascial confinement. Furthermore, the thoracolumbar fascia, often presumed to be involved, lies deeper and is not directly accessed by the block.12As such, the ESPB may be more accurately described as a muscle-bone interface block or a volume-dependent myofascial injection rather than a true anatomical fascial plane block. This distinction is important, as it may explain the inconsistent spread and variable clinical efficacy observed across studies. It is not merely a semantic discussion. Safety of Fascial plane blocks Emerging research suggests that part of the analgesic effect attributed to FPBs may arise from systemic absorption of the local anesthetic (LA). Measurable plasma concentrations following high-volume interfascial injections indicate that non-specific, systemic effects on the central nervous system could play a role in pain modulation. This may help explain why some FPBs appear more effective when administered after surgery. The altered physiology, increased vascularity, and active inflammatory milieu in the immediate postoperative period may enhance systemic absorption, amplifying analgesic effects that are not solely attributable to regional nerve blockade. In fact, our recent study published in Anesthesiology demonstrated that systemic absorption of local anesthetic following fascial plane block was approximately twice as high as that observed with surgical intercostal nerve blocks—a technique traditionally recognized for its high systemic uptake.13 FPBs are often characterized as low-risk interventions, especially when compared to neuraxial blocks. However Local anesthetic systemic toxicity (LAST) remains a relevant concern due to the large volumes often required.14 In combined techniques or continuous infusions, cumulative dosing may inadvertently exceed recommended thresholds. Postoperative anatomical disruption can further alter LA dynamics, creating unexpected complications. Physiological changes during pregnancy, such as decreased plasma albumin and α1-acid glycoprotein concentrations, can significantly influence the pharmacokinetics of local anesthetics. These proteins serve as primary binding sites for amide-type local anesthetics; when their levels decline, as commonly observed in pregnant patients, the unbound (free) fraction of the drug increases. This heightened free fraction enhances the potential for systemic toxicity, as only unbound drug is pharmacologically active and capable of crossing cellular membranes, including the blood-brain and placental barriers. Consequently, standard doses may produce exaggerated systemic effects in pregnant patients, underscoring the need for careful dose adjustment and vigilant monitoring.15 16 Their superficial location and ultrasound-guided nature support this perception, making them attractive options in patients with coagulation concerns or spinal abnormalities. Yet not all FPBs are inherently safe. Deep variations, such as anterior QLB, bring the needle in close proximity to major vascular structures like lumbar arteries. Other blocks, such as those involving the thoracic wall, risk encountering arteries like the thoracoacromial branches unless Doppler is employed. Limitations in Comparative Research Despite their widespread use, FPBs have not been adequately compared to more established techniques such as intrathecal morphine (ITM), paravertebral blocks (PVBs), or traditional neuraxial approaches. Many of the available studies are single-center, underpowered, and hampered by poor blinding and inconsistent outcome measures.5 Properly blinded studies might change the perception.13 17–20 Research priorities should shift toward multicenter trials with standardized definitions, validated pain endpoints, and longer-term follow-up. Without such data, the full therapeutic potential—and limitations—of FPBs will remain uncertain. Clinical limitations We can safely conclude that most fascial plane blocks lack any consistency in their clinical outcomes. However it is often omitted that even if they do add some analgesic benefit the duration of this effect rarely exceeds 6 hours.21 As a result, the duration of effective analgesia with single-injection fascial plane blocks is inherently limited. While continuous catheter techniques can extend their efficacy, they introduce additional challenges. Catheters may hinder early mobilization, require bilateral placement for adequate coverage, and involve complex local anesthetic dosing strategies. These logistical and pharmacological burdens often run counter to the core principles of Enhanced Recovery After Surgery (ERAS), undermining the very benefits these blocks were intended to support. In our experience these blocks are most effective in a non-standardized way to alleviate pain in the rare cases of breakthrough pain in postoperative care units. Emerging approaches in pain phenotyping suggest that regional techniques, including fascial plane blocks, may find their most appropriate role as targeted interventions for individuals identified as pain-sensitive or pain-intolerant. These patients, often characterized by heightened nociceptive processing or poor coping mechanisms, may derive meaningful benefit from regional rescue strategies when standard multimodal analgesia proves insufficient. In contrast, pain-adaptive individuals—those with resilient neuropsychological and physiological profiles—tend to recover well without the need for additional regional interventions, underscoring the potential for a more individualized, phenotype-driven approach to perioperative pain management.22 Additionally, the patient experience in recovery—when pain is most pronounced—can amplify perceived benefits of any intervention, including those with limited anatomical efficacy. Placebo responses in this context should not be discounted. Conclusion Fascial plane blocks represent a notable advancement in regional anesthesia, especially within the context of modern, less invasive surgery. Their appeal lies in simplicity, adaptability, and a generally favorable safety profile. However, their widespread adoption must be accompanied by a balanced appraisal of their mechanistic limitations, clinical variability, and underexplored risks. Future research must prioritize robust comparative data, better mechanistic insight, and clearly defined clinical endpoints. Enthusiasm alone cannot substitute for evidence. Used appropriately, FPBs can be adjuncts in perioperative pain management—but they should not be mistaken for comprehensive solutions. Don’t waste your valuable clinical time in adding these blocks in your normal standard enhanced recovery program. Use them as a rescue option in PACU, when surgery deviates from original plan, or you have patients who are more pain sensitive.References Rawal N. 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