Abdominal Surgery Performed in Awake Patients Under Neuraxial Anesthesia: A Systematic Review Across Surgical Specialties

Abstract

Background: Neuraxial anesthesia (NA) is increasingly utilized across various surgical specialties, particularly for abdominal procedures, making it a potential alternative to general anesthesia (GA). Methods: This narrative review was conducted following the PRISMA guidelines for systematic reviews to report on the application of NA worldwide and across various surgical fields. Results: The findings indicate that while NA is gaining popularity, its adoption varies significantly by procedure type and specialty. Evidence supporting its use in major abdominal surgeries remains limited, with most studies focusing on pelvic and minor procedures. The emerging concept of awake surgery under NA shows promising potential, as preliminary data suggest benefits in reducing perioperative morbidity and enhancing recovery. Despite these advancements, gaps in the literature highlight the need for further high-quality trials to establish NA as a safe and routine alternative to GA. Conclusions: NA is increasingly explored across different surgical specialties as a feasible and effective option for abdominal procedures. However, despite this growing interest, solid evidence supporting its use in major abdominal surgery remains limited.

1. Introduction

The origin of neuraxial anesthesia (NA) sinks its roots to the end of 19th century [1], when J. Leonard Corning (1855–1923) injected two doses of about 2 mL of 3% cocaine into the T11–T12 interspinous space, demonstrating a progressing pinprick sensation impairment in the legs, genitalia, and lumbar region which advanced over twenty minutes. The effects completely and spontaneously reverted with no sensory alterations. Although Corning appreciated the clinical value of spinal anesthesia, both in animal and human subjects, he never applied it in a surgical procedure and published his results in 1885 [2].

This anesthesiologic practice quickly advanced with the refinement of techniques and tools, such as the development of the epidural block and continuous anesthesia methods. Over the decades, innovations like multi-lumen needles and combined techniques have further enhanced safety and effectiveness, making NA a cornerstone of modern anesthetic practice. This progress has revolutionized pain management and surgical procedures, offering patients safer and more effective options for anesthesia. Neuraxial anesthesia has evolved into a versatile alternative to general anesthesia (GA) across various surgical contexts. While GA has traditionally been the standard for major surgeries due to its ability to ensure unconsciousness and airway control [3], advances in neuraxial techniques have broadened options for both open and laparoscopic procedures [4]. NA is particularly beneficial for elderly and frail patients [5] who may not tolerate the systemic stress of GA, while undergoing surgeries for conditions such as hernias, colorectal diseases, urologic and gynecologic problems, many of which are now treated laparoscopically. NA has the potential to minimize risks such as delirium, ileus, and ventilation-related complications, supporting quicker and safer recoveries [6]. The COVID-19 pandemic highlighted the value of NA, as it avoids aerosol-generating procedures like intubation [7], thereby reducing the risk of viral transmission to healthcare workers. During this time, many hospitals adopted NA for eligible patients, especially those with or suspected of having COVID-19 [8]. This approach ensured timely surgical care while reducing ICU admissions and the need for mechanical ventilation, alleviating strain on healthcare systems [7]. Consequently, NA has gained recognition as a safe and efficient anesthetic choice in diverse clinical scenarios. The potential of NA in abdominal procedures remains largely unexplored. Its current applications are sporadic, and a comprehensive review is lacking.

2. Materials and Methods

2.1. Objectives

The primary outcome was to provide a narrative overview of the state-of-the-art regarding the application of NA in abdominal surgical procedures.

2.2. Protocol and Registration

Methods of the analysis and inclusion criteria were not specified in advance nor documented in a protocol. The review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines [9]. The present systematic review is registered on the Open Science Framework (https://osf.io; registration number: DZP6B).

2.3. Eligibility Criteria

Published, peer-reviewed papers including case reports and original studies regarding the application of NA in abdominal surgical procedures were considered eligible to be included in the study. Animal studies, abstracts only or unpublished data, were excluded. Any language except English was excluded from the analysis, to facilitate reproducibility from other researchers. Studies included in systematic reviews and meta-analyses were screened and included in the bibliography, if not already present.

2.4. Information Sources

A MEDLINE bibliographical search was performed up to 31 August 2024. No backward date restrictions were applied to the research. References of the papers deemed eligible to be included in the review were manually assessed to detect any important missing study.

2.5. Search

We applied the following research queries with Boolean operators:

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awake AND surgery NOT neurosur*

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neuraxial AND minimally AND invasive

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neuraxial AND surgery NOT neurosur*

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neuraxial AND colect*neuraxial AND abdom*

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(non-intubated) AND surgery NOT neurosurg*

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neuraxial AND laparosc*

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thoracic spinal-epidural anesthesia

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spinal AND abdom* AND surgery

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((laparosc*) AND (conscious)) AND (sedation)

2.6. Study Selection

Two independent authors (J.C. and C.F.) screened the titles and abstract of all retrieved articles searching for potentially eligible studies. In case of uncertainty during title screening, papers were initially included, and the full-length abstracts and texts were later inspected to assess their appropriateness. Studies were considered eligible if the following criteria were met: (1) at least one major or minor abdominal procedure under pure NA, (2) abdominal wall reconstruction surgeries entering the peritoneal cavity and (3) both open and laparoscopic approaches.

Exclusion criteria included the following: (1) non-abdominal procedures (e.g., thoracic surgery, neurosurgery, orthopedic surgery), (2) pediatric population, and (3) obstetric or transvaginal gynecological procedures, (3) cesarean delivery, (4) neuraxial techniques used for sole analgesia (alone or in adjunct to GA), and (5) animal studies. In the case of duplicate publications, only the most recent or most informative studies were included in the analysis. Once retrieved the final list of studies to be included, results were compared, and disagreements regarding their inclusion or not were resolved by consensus with a third reviewer (C.M.).

2.7. Data Extraction

This systematic review was performed using Rayyan© (https://www.rayyan.ai). After reviewing the full texts of eligible studies, two authors (J.C. and C.F.) independently performed the data extraction through a data-extraction sheet and cross-checked all the results. Extracted variables included general study characteristics (e.g., title, first author, year of publication, country of origin, study design and study population), clinical data (e.g., surgical specialty, surgical approach, surgical procedure, type of anesthesia with its related number of subjects), outcomes and conclusions. No variables were added after the beginning of the review.

3. Results

The diagram of the selection process is shown in Figure 1, while the characteristics of the eligible studies and main outcomes are summarized in Table S1.

The systematic search identified 14,848 studies. Among them, 614 duplicated results were excluded, and 13,971 studies were excluded by title screening, eventually leaving 263 studies for abstract and full-text review. Of these, 165 studies were excluded because they were systematic narrative/technical review or metanalyses (n = 33); studies including non-trans-abdominal procedures (n = 19) or non-abdominal procedures (e.g., thoracic, orthopedic, neurosurgical) (n = 19); studies including NA as adjunct to GA (n = 16); studies including a pediatric population (n = 9); letters to the editor, commentaries, surveys, economic appraisals or historical papers (n = 16); abstracts only (n = 7); studies assessing truncal blocks or local anesthesia (n = 23), unknown surgical procedures (n = 10), or a trial protocol (n = 1); studies in a language other than English (n = 1); or studies not reporting surgical data (n = 8), or for other reasons (n = 3). Twenty-one studies were included at this time after inspection of the citations of the systematic reviews. Eventually, 119 publications were included in the review.

Abdominal surgery performed with NA has been reported worldwide. A total of 31 countries have contributed to the literature, with 3 publications being multinational. The top 3 contributors were Italy (n = 25), India (n = 20), and the U.S.A. (n = 16). Figure 2 graphically represents the number of contributing manuscripts per country.

The oldest contribution to the literature is the manuscript by Stanley L.L. et al. [10], published in 1919. However, there has been a clear increase in publications in recent years, particularly over the last decade. The peak year for publications on abdominal surgery performed with NA was 2023, with 11 publications. Figure 3 visually illustrates the rising trend in publications over time.

Despite the increasing number of published manuscripts, the majority remain low-evidence studies, predominantly case reports and case series, which account for 62% of total publications. The second most common study type is randomized controlled trials (RCTs), representing 22% of the publications. Figure 4 presents the distribution of study types and their frequency.

4. Discussion

Our systematic review highlights the extensive and increasing use of NA reported in the literature. NA is utilized across multiple specialties and countries worldwide. Abdominal procedures in the pelvis are the most commonly performed with NA possibly due to their favorable anatomical location and involvement of lower spinal segments. A significant number of cholecystectomies are also conducted using this technique, particularly in highly populated countries. While the routine application of NA in major abdominal procedures remains limited, emerging evidence suggests its potential utility in vascular and general surgery. Key outcomes investigated include pain control, length of hospital stay, feasibility, and overall effectiveness. From our study, NA may offer effective pain relief without significant respiratory or cardiovascular impairment, even in patients with comorbidities. NA may minimize the need for sedatives, opioids, and airway management, reducing the potential for adverse effects.

Older patients are at greater risk of perioperative complications due to the natural decline in physiological function and reduced functional reserve. This decline diminishes the body’s ability to cope with acute stress, posing significant challenges for surgical and anesthetic management in the elderly [11]. However, today the paradigm is shifting, and age alone is no longer regarded as a reliable predictor of perioperative risk. A new concept is emerging, where frailty—a state of diminished physiological reserve beyond normal aging—has become a key predictor of poor surgical outcomes [11]. In surgical populations, frailty rates range from 10.4% to 37% in general surgery patients [12], and 19% to 62% in patients undergoing vascular, cardiac, thoracic, and orthopedic surgeries [11]. Great concern arises from the potential consequences of GA in elderly patients, and new techniques such as NA are emerging as possible alternatives.

A potential advantage of NA for frail patients is the need of minimal sedation during surgery, which could theoretically reduce the risk of POCD [5]. In older adults, anesthesia can increase the risk of persistent postoperative cognitive decline (POCD) [13]. POCD occurs in more than one third of cardiac surgeries and up to 26% of non-cardiac surgeries; this not only increases mortality and prolongs hospital stays but also diminishes quality of life and raises healthcare costs [13]. A key challenge remains whether pharmacological interventions can effectively reduce the impact of perioperative brain damage.

Despite mixed findings in the literature, regional anesthesia is suggested for frail patients as it has also been linked to reduced risks of thrombolytic events, blood loss, and deep vein thrombosis [4]. Additionally, regional anesthesia provides better postoperative pain control, improving patients’ comfort and reducing the likelihood of adverse cardiac events [5]. For these reasons, alternative techniques to GA are being proposed for operations that have historically required the use of patient intubation.

GA is typically used during radical prostatectomy, but recent studies suggest that NA, including epidural or spinal blocks, can be a safe and effective alternative in urological surgeries [14,15,16,17,18,19,20,21,22,23]. Research by Karl et al. [24] showed that NA could reduce both morbidity and mortality in patients undergoing open radical cystectomy. Additionally, studies by Salonia et al. [25] demonstrated that open radical prostatectomy performed under NA resulted in reduced blood loss, less postoperative pain, and quicker recovery. Another case series by Bhosale et al. [26] suggests that NA may be practical and beneficial in renal transplant surgery.

Similarly to urologic surgery, GA is the standard anesthesiologic approach used for laparoscopic sleeve gastrectomy, but it can exacerbate existing pulmonary issues in obese patients, leading to postoperative complications, and, in turn, to increased mortality [27]. In contrast, NA is emerging as a promising alternative, preventing the typical drawbacks of mechanical ventilation. While little research has focused on regional anesthesia in bariatric surgery, a few case series and retrospective studies suggest it is effective and well-received by patients, surgeons, and anesthetists alike [28]. In the positive experience of Soltan et al. [27] on about 100 cases, regional anesthesia demonstrated significant advantages over GA, including faster recovery, reduced opioid use, and fewer complications, making it a valuable alternative for morbidly obese patients undergoing bariatric surgery.

The successful use of NA in patients with cardio-pulmonary diseases [29] undergoing gastrectomy for cancer has demonstrated that a tailored anesthetic approach enables curative intent surgery with minimal peri-operative risk, in patients for whom GA would have increased the risk of difficult weaning and severe postoperative complications.

Within the field of abdominal surgery, numerous studies have investigated the use of NA during cholecystectomy [30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56]. A retrospective cohort study of 3492 patients by Sinha et al. [57] affirms that laparoscopic cholecystectomy done under spinal anesthesia should be the anesthesia of choice, as it does not require any change in technique and, at the same time, offers numerous advantages in both intraoperative and postoperative outcomes, as compared to GA. A retrospective randomized study by Donmez et al. [58] suggest that spinal anesthesia may be a promising approach for laparoscopic surgery with less to null occurrence of shoulder pain compared to GA, however larger prospective studies are required to validate these findings. A meta-analysis by Longo et al. [59] found that NA was associated with a 25% prevalence of shoulder pain, higher rates of intraoperative hypotension and bradycardia, and a lower incidence of postoperative nausea and vomiting compared to GA, requiring conversion in only 3.4% of cases and showing no respiratory advantages for patients with normal pulmonary function. In conclusion, a large number of studies affirm that NA for cholecystectomy either open or minimally invasive is safe and feasible and some emphasize the use of NA in patients with pre-existing comorbidities.

In the field of hepatobiliary surgery, only a few studies have reported experiences with the use of NA [60,61,62]. A pilot retrospective study of 46 patients by Rocca et al. [63] shows that NA is safe and feasible, allowing minor and major liver resections as well as pancreatic surgery including a minimally invasive approach (laparoscopic) if surgery is performed in referral centers by experienced anesthesiologists and surgeons.

Some case reports lead the way to a promising use of NA in robotic surgery showing that the combination of robotic surgery and locoregional anesthesia guarantees both surgical and anesthetic minimal invasiveness for hepatic wedge resection [64] and for partial nephrectomy [65].

The use of NA for laparoscopic appendectomy highlights its prospective in emergency surgery including a good postoperative pain control, absence of post-operative nausea and vomiting as well as intubation-associated complications [66], and shorter hospital length of stay compared to GA [67,68,69].

Although some anesthetists and surgeons may be reluctant to use regional anesthesia for both elective and emergency ventral hernia repair, some case series show that NA may represent an excellent option in obese patients with a high respiratory risk [70] or geriatric patients with severe respiratory diseases [71,72,73,74,75]. A case series of 58 patients reports no difference between spinal and general anesthesia in postoperative quality of life after TAPP inguinal hernia repair [76].

NA is primarily utilized in vascular surgery for limb revascularization procedures, where it offers effective regional control of pain and reduces the need for GA. This translates into reduced morbidity and possibly mortality, as suggested by randomized and non-randomized data. However, its application has also been explored in selected cases of open abdominal aortic aneurysm repair, particularly in patients with severe pulmonary disease who are unsuitable for GA and not eligible for endovascular aneurysm repair (EVAR). In these cases, NA provides a valuable alternative by minimizing the respiratory complications associated with GA, making surgery possible for high-risk patients. Although evidence is limited to case reports [77,78,79,80], the technique shows promise for improving outcomes in patients who would otherwise face significant perioperative risks.

Neuraxial labor analgesia remains the gold standard for its effective and flexible pain management during childbirth, with the added benefit of conversion to cesarean delivery anesthesia when needed, reducing the need for general anesthesia and thereby lowering the associated risks in this population [81]. However, a literature search on NA in gynecological surgery highlights its efficacy and potential advantages across a variety of procedures, including transabdominal hysterectomy, adnexectomy, and myomectomy [82,83,84,85,86,87,88,89,90,91,92,93,94,95]. Techniques such as single-shot spinal, combined spinal-epidural, and epidural anesthesia have been extensively evaluated, demonstrating reliable pain control and feasible application in both open and laparoscopic surgeries. For example, Wodlin et al. [96] demonstrated that spinal anesthesia reduced the need for postoperative care and improved recovery outcomes in gynecologic abdominal surgeries. Similarly, Hwang et al. [97] found combined spinal-epidural to be a safe and feasible option for non-obese patients undergoing gasless laparoscopic surgery. Moreover, Wodlin et al. [96] also emphasized that spinal anesthesia reduces the requirement for postoperative opioid use, highlighting its advantage in minimizing the consumption of morphine and other opioids. In their case report, Moawad et al. [98] proposed that total laparoscopic hysterectomy under epidural anesthesia was feasible with bilevel positive airway pressure augmentation for respiratory support, illustrating the versatility of NA even in fragile patients undergoing laparoscopic procedures. These findings collectively underscore that NA is a safe and effective alternative to GA in gynecological surgeries, offering particular benefits in terms of enhanced postoperative recovery, reduced opioid consumption, and improved pain management.

Most of the studies regarding the application of NA in colorectal surgery consist of case reports [99,100] or small case series [101,102], with only one randomized clinical trial [103] standing out among them. This disparity in study designs underscores a widespread deficiency in large-scale, high-quality research within this domain [104,105,106,107,108,109,110,111]. Most procedures were conducted using the open surgical approach, with comparatively fewer utilizing laparoscopic or other minimally invasive techniques. Anesthetic strategies varied considerably among the studies, including differences in the type of anesthesia, drugs administered, and sensory targets, highlighting the absence of a standardized best practice. Additionally, the outcomes reported were often broad, poorly defined, or inconsistently documented, with some studies failing to clearly specify the metrics used to evaluate success. This lack of clarity complicates efforts to compare results across studies and limits the ability to draw reliable conclusions about the efficacy of the approaches examined. Furthermore, many studies suffered from limited statistical power due to small sample sizes and methodological shortcomings, thereby diminishing the reliability and generalizability of their findings. Collectively, these investigations exhibit a lack of systematic design, characterized by inconsistent methodologies and outcome reporting.

Despite randomization and blinding, the trial by Ellakany et al. [103] included heterogeneous surgical procedures ranging from colic to gastric, as well as pancreatic resection. Their data showed shorter post-anesthesia care unit stay, better postoperative pain relief and patient satisfaction for NA rather than GA. Nevertheless, strong conclusions or evidence-based recommendations cannot be drawn, emphasizing the urgent need for rigorous and well-structured research to better evaluate these techniques. Despite these limitations, authors frequently suggested that NA may hold promise for successful application in both upper and lower-gastrointestinal surgery [112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129,130].

Minimally invasive procedures represent an interesting field of application for NA. The conventional reliance on GA for such surgeries is primarily driven by the need for pneumoperitoneum induction—a cornerstone of minimally invasive techniques—and the associated requirement for muscle relaxation. However, there is a growing body of evidence supporting the feasibility of NA in minimally invasive surgery [131,132,133]. Regional anesthesia in laparoscopy offers several advantages, including faster recovery, a reduction in postoperative nausea and vomiting, less pain, shorter hospital stays, cost savings, improved patient satisfaction, and overall safety [134]. NA avoids common issues like sore throat, muscle pain, and airway trauma that are generally associated with GA [134].

Recent evidence highlights the protective role of regional anesthesia, particularly NA, in reducing the perioperative stress response. Epidural anesthesia has been found to attenuate the endocrine and metabolic response to surgery, lowering the levels of stress markers like catecholamines and cortisol, which are typically elevated during general anesthesia [135]. This reduction in surgical stress response positively impacts postoperative recovery, including faster restoration of gastrointestinal function, improved glucose tolerance, and a shorter hospital stay [136]. Notably, epidural anesthesia has also been shown to decrease postoperative ileus and improve pain management, which contributes to better surgical outcomes [137]. Overall, regional anesthesia, by mitigating the trauma-related stress response, enhances recovery and reduces postoperative complications, underscoring its importance in modern surgical care.

Negative results regarding the use of regional anesthesia were reported by the largest randomized trial comparing regional and general anesthesia for hip surgery in older adults, the REGAIN trial [138]. This study found no difference in the incidence of postoperative delirium between patients undergoing hip surgery under general or regional anesthesia. Its findings were later confirmed by another randomized trial that focused on similar outcomes [139]. Despite this evidence, the potential role of NA compared with GA remains unexplored in abdominal procedures, where patients frequently present with complex systemic conditions and surgery is typically performed under GA. Demonstrating that NA can achieve comparable outcomes in this setting could broaden therapeutic options for abdominal surgery patients and prompt a renewed evaluation of the risk-benefit profile, particularly in the aging population.

To achieve adequate anesthesia of the abdominal metameres, NA is often administered through thoracic spinal anesthesia. This technique remains debated due to safety concerns, particularly the risk of spinal cord injury and potential neurological complications [140]. Nevertheless, available studies and clinical experience demonstrate that it can be safely applied without risk of permanent neurological damage [141]. Additional concerns include excessive cephalad spread of the anesthetic, hypotension, and bradycardia, although these effects are generally transient and manageable. Respiratory compromise has also been discussed but appears minimal, as diaphragmatic function is largely preserved and exhalation remains unaffected except during forced expiration [142].

Anesthesia awareness refers to the postoperative recall of sensory perception while under general anesthesia, thus equipped with breathing devices like an endotracheal tube or laryngeal mask airway [143,144]. This undesired event can lead to severe psychological effects, including the onset of chronic post-traumatic stress disorder (PTSD) [145]. However, a shift to this concept is emerging [146]; a standardized and reproducible approach to NA allows constant interaction between all key players involved in the surgical procedure—surgeons, anesthesiologists, the care team and the patient. The latter is conscious, breathing spontaneously, and able to communicate, even during surgeries that typically require GA. This approach extends the concept of minimally invasiveness also to anesthesia, potentially extending the surgical indication also to those considered unfit (or at extremely high risk) for GA.

A number of limitations affect the present investigation. With the objective of reporting a broader range of experiences with NA, a meta-analysis focusing on a specific outcome was not performed, which limits the scientific impact of the present study. Furthermore, case reports and case series on the topic, being of low levels of evidence, may introduce bias in favor of NA. Therefore, the findings of individual studies, as well as the overall conclusions of this systematic review, should be interpreted with caution.

5. Conclusions

Neuraxial anesthesia is increasingly adopted across multiple specialties for abdominal surgical procedures performed in awake patients, offering an alternative to GA. However, evidence in the literature remains limited, particularly for major abdominal surgeries. In contrast, NA appears to have gained more acceptance for pelvic and other minor procedures. The concept of awake surgery with NA shows significant potential based on the preliminary data highlighted in this review. Further investigation in a trial setting is warranted to evaluate NA as a safe and routine alternative to GA.