Introduction

Spine surgery is performed to correct spinal pathologies that cause pain and instability in both adult and pediatric patients and is one of the fastest expanding surgical specialties in the world [1,2,3]. Such procedures are commonly associated with severe postoperative pain, significant blood loss, functional limitation, and potential postoperative complications, due to the invasiveness of the surgery and prolonged hospitalization. In this regard, in recent years, clinical pathway and care methods emerged associated with the concept of fast-track programs. Fast-track surgery procedures, also identified as Enhanced Recovery After Surgery (ERAS), were first introduced in the 1990s by Henrik Kehlet [4]. The procedure consists of an evidence-based approach of care with the involvement of a multidisciplinary team made up of surgeons, nursing, anesthesiologists, physiatrists, physiotherapists and nutritionists, designed to prepare patients and reduce the impact of surgery, allowing them to recover more rapidly [4]. These programs aim to reduce stress related to surgery focusing on patient’s psychological well-being and the early mobilization, resulting in a rapid recovery and, consequently, a shorter length of hospital stay (LOS) [5]. LOS reduction leads, in turn, to a lower risk of infections and adverse events as well as to a reduction of the intraoperative complications and health care cost [6]. The procedures manage the patients care into a multimodal and multidisciplinary approach that include patient specific education, optimization and information on the pre-, intra-, and postoperative steps, improvements in surgical and anesthetic techniques, advances in postoperative multimodal analgesia, early rehabilitation and ambulation, early food intake, and discharge within 24 hours post-surgery [7, 8]. In the last few years, fast-track programs are successfully developing and are always undergoing improvement in several areas of orthopedic research and surgery. Particularly, there are several evidence to support the use of enhanced recovery pathways for patients undergoing to hip and/or knee orthopedic surgery. Although this type of pathways has several advantages and represents the standard of care in many surgical areas, to date, the clinical effectiveness of fast-track procedures has not been regularly recognized or accepted for all orthopedic field and there is still work to be done particularly in spine surgery [9,10,11,12,13]. Existing fast-track spine protocols are still in the early stage and vary significantly in their pre-, intra-, and postoperative elements, rendering difficult to assess their real effectiveness, farther there remains a lack of consensus on which specific elements may be relatively more effective. Thus, to highlight the most recent improvement in the pre-, intra-, and postoperative fast-track components and their clinical evidence in patients undergoing different spine surgery, we carried out a systematic review in order to provide an evidenced-based assessment of specific interventions, measurement, and associated outcomes linked to enhanced recovery pathways in spine surgery field.

Methods

Eligibility criteria

The PICOS model (population, intervention, comparison, outcomes, study design) was used to design this study: (1) studies that considered patients undergoing spine surgery (Population) submitted to, (2) fast-track protocols (Interventions), (3) with or without a comparison group (standard protocol) (Comparisons), (4) that reported pre-, intraoperative, and postoperative key components and clinical outcomes of the fast-track interventions (Outcomes), in (5) randomized, retrospective, and prospective e studies (Study design). Studies from February 1, 2012, to August 1, 2022, were included in this review if they met the PICOS criteria. We excluded studies that evaluated (1) surgeries other than spine, (2) patients undergoing spine surgery with other concomitant severe pathological conditions (i.e. tumor, metastases), and (3) articles with incomplete outcomes or data. Additionally, we excluded reviews, case reports or series, letters, comment to Editor, in vivo and in vitro studies, pilot studies, meta-analysis, editorials, protocols and recommendations, guidelines, and articles not written in English.

Search strategies

Our literature review involved a systematic search conducted in August 2022. We performed our review according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement [14]. The search was carried out on three databases: PubMed, Scopus, and Web of Science Core Collection. The following combination of terms was used (spine disease OR spine surgery) AND (fast-track OR enhanced recovery after surgery OR enhanced recovery programs), and for each of these terms, free words, and controlled vocabulary specific to each bibliographic database were combined using the operator “OR”. The combination of free-vocabulary and/or Medical Subject Headings (MeSH) terms for the identification of studies in PubMed, Scopus and Web of Science Core Collection were reported in Table 1 (Supplemental Material).

Table 1 Basic characteristics of included literatures studies on spine surgery
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Selection process

After submitted the articles to a public reference manager (Mendeley Desktop 1.19.8) to eliminate duplicates, possible relevant articles were screened using title and abstract by two reviewers (DC and FS). Studies that did not meet the inclusion criteria were excluded from review and any disagreement was resolved through discussion until a consensus was reached, or with the involvement of a third reviewer (MF). Subsequently, the remaining studies were included in the final stage of data extraction.

Data collection process and synthesis methods

The data extraction and synthesis process started with cataloguing the studies detail. To increase validity and avoid omitting potentially findings for the synthesis, two authors (DC and FS) extracted and performed a Table (Table 1) taking into consideration: study design, patients’ number, age and gender, comparative analysis presence, surgery (indication and operation types), spine levels, comorbidities, intensive care unit length of stay (ICU LOS), hospital length of stay (LOS), complications, readmission and reoperation rates, follow-up, and outcomes/endpoints. The other Table (Table 2) takes into consideration fast-track procedures (pre-, intra, and postoperative). Preoperative components included patient education, consultation, physical therapy, nutrition and pain management. Intraoperative components included the day of surgery, anesthesia and pain management, fluid and blood transfusion, and nausea-vomiting prophylaxis. Finally, postoperative components included early mobilization, pain regimen, deep venous thrombosis (DVT) prophylaxis, nutrition status, early drain/catheter removal, antibiotic prophylaxis, fluid maintenance, and discharge.

Table 2 Pre-, intra- and postoperative fast-track procedures
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Assessment of methodological quality

The methodological quality of selected studies was independently assessed by two reviewers (DC and FS), using the Quality Assessment Tools of the National Heart, Lung, and Blood Institute (NHLBI) [72]. The tool included 14 items, which assessed the possible sources of bias. For each item, we categorized “Yes” if the criterion was explicitly met, “No” if the assessed criterion was not met. In case of disagreement, the reviewers attempted to reach consensus by discussion; if this failed, a third reviewer (MF) was consulted making the final decision.

Results

Study selection and characteristics

The initial literature search retrieved 790 studies. Of those, 328 studies were identified using PubMed, 266 using Scopus, 196 were found in Web of Science Core Collection. Subsequently, articles were submitted to a public reference manager to eliminate duplicate. The resulting 461 articles were screened for title and abstract and 136 articles were reviewed to establish whether the publication met the inclusion criteria. Finally, 57 articles were considered eligible for this review. Search strategy and study inclusion and exclusion criteria are detailed in Fig. 1. Of these articles, 46 were retrospective cohort studies, 10 were prospective cohort studies and 1 was randomized clinical trial (RCT).

Fig. 1
figure 1

PRISMA flow diagram for the selection of studies

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Assessment of methodological quality

In our quality assessment for spine surgery the 44% [15, 23, 27, 29, 32,33,34,35,36,37,38, 40,41,42, 46,47,48,49, 51, 55, 56, 61, 67, 68, 70] of the studies were rated strong, 25% [17, 18, 21, 22, 25, 28, 31, 39, 43, 44, 60, 62, 63, 65] were rated moderate, and 32% [16, 19, 20, 24, 26, 30, 45, 50, 52,53,54, 57,58,59, 64, 66, 69, 71] were rated weak. Methodological weaknesses that led to moderate or weak quality scores often included the lack of a sample size justification, power description, or variance and effect estimates, the lack of subjects selected or recruited from the same population, the lack of results evaluation more than once over in time, the lack of blinded assessor and the lack of measurement of potential confounding variables. Risks of bias assessments for each study were summarized in Table 3.

Table 3 National Heart, Lung, and Blood Institute (NHLBI) quality assessment tool
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Studies results

General information’s

A total of 11,385 (with a range from 17 to 2579) and 6040 (with a range from 15 to 1563) patients were analyzed for the fast-track and non-fast-track groups (traditional protocol) respectively. Mean age of the patients was 52 years (with range from 13.2 ± 3.2 to 76.68 ± 4.83) for fast-track group, and 54 (with range from 14.3 ± 1.9 to 7 6.38 ± 4.48) for non-fast-track group. Most of the patients were women (8515) compared to men (8171). In addition, 8 studies analyzed adolescent patients under the age of 18.

Types of spine surgery and pathological conditions

Procedures associated with the spine included minor, major, and complex surgeries, such as arthrodesis, corpectomy, microdiscectomy, decompression, laminectomy, laminoplasty, open and minimally invasive posterior lumbar interbody fusion (PLIF), transforaminal lumbar interbody fusion (TLIF), oblique lumbar interbody fusion (OLIF), anterior lumbar interbody fusion (ALIF), anterior cervical discectomy and fusion (ACDF), percutaneous endoscopic transforaminal discectomy (PETD), percutaneous endoscopic lumbar interbody fusion (PELIF), and cervical disc arthroplasty (CDA). Because the types of spine surgery were not standardized across the 57 studies, it was difficult to quantify the prevalence of any single type of spine procedure among the fast-track protocols. However, most fast-track protocols were implemented for lumbar spine procedure, mainly through techniques such as PLIF and TLIF and at the spinal levels L1-L5. In addition, of the 57 articles included in this review, 81% presented a comparison with a standard/traditional protocol (non-fast-track) while the others (19%) evaluated different fast-track protocols in patients undergoing spine surgery. It was shown that fast-track programs were applied to different spine diseases, mainly for degenerative pathological conditions as disc herniation, stenosis, spondylolysis, radiculopathy, spondylolisthesis (78%), for adult spinal deformity (5%) or both (3%). In addition,, a total of 1200 patients (8 studies, 14%) were treated for adolescent idiopathic scoliosis using a posterior approach. Of these 8 studies, 6 were retrospective, while the other 2 were prospective. Concerning adult deformities, they were evaluated in 3 retrospective studies, using an anterior or posterior approach. Finally, 45 studies evaluated patients treated for degenerative diseases, using an anterior or posterior approach. Of these, 36 studies were retrospective, 8 studies were prospective, and only one study was a RCTs.

Comorbidity

Several comorbidities such as osteoporosis, frailty, obesity, sarcopenia, hypertension, diabetes, chronic cardiovascular disease, chronic obstructive pulmonary disease, obstructive sleep apnea, chronic kidney and liver diseases, depression and dementia were reported in 30 studies.

Components of fast-track procedures in spine surgery

Preoperative

In this review, one of the principal preoperative interventions was patient education and information (detailed information provided to the participants and their family members regarding the surgical procedure, potential complications, rehabilitation, and hospital discharge) (86%), followed by multidisciplinary consultations (geriatric, psychological, nutritional, behavioral health) to guide patients’ expectations as well as to inform them on the risks about intra- and postoperative pathway (61%), nutrition (minimized fasting) (61%), pain management (analgesic drugs use) (33%) and physical therapy (21%).

Intraoperative

In the studies examined, principal intraoperative components were multimodal analgesia and pain management (82%), antimicrobial/antibiotic prophylaxis (44%), normothermia/normovolemia maintenance (53%), and general anesthesia (42%). Additionally, nausea and vomiting prevention (with antiemetics or compression hosiery) (37%), carbohydrate loading 4 hours before surgery and clear fluid and solid fluid fasting for 2–6 hours before surgery (42%), transfusion control (28%), tranexamic acid (TXA) use (including oral and parenteral formulations) as strategy to minimize bleeding (33%) and the avoidance of catheter/drain (22%) represented the key fast-track interventions in spine surgery.

Postoperative

The principal postoperative elements were pain management with multimodal analgesia use (89%), and early mobilization within 24 hours with rehabilitation/physiotherapy (72%). Other common elements were early nutrition and bowel regime maintenance (74%), catheter/drain removal within 24 hours after surgery (54%) and thromboprophylaxis (37%). Finally, normovolemia maintenance (16%) and antimicrobial/antibiotic prophylaxis (21%) were others postoperative key element.

Length of hospital stay, complication and readmission rates

The primary outcome in fast-track studies on spine surgery was LOS. A LOS of 2–5 days for the spinal deformities, such as adolescent idiopathic scoliosis was observed, while a LOS of 2–12 days were detected for the degenerative diseases as disc herniation, stenosis, spondylolysis, radiculopathy and spondylolisthesis. Most studies evaluated a fast-track protocol (81%) versus a conventional (non-fast track) protocol (19%), reporting a significantly reduced LOS (in 81% of studies), without increasing complication or readmissions rate in patients treated with fast-track, regardless of follow-up (from 1 month to 2 years), pathology and surgical approach used. Four studies instead reported no significant differences in LOS between the fast-track and non-fast-track groups [16, 33, 51, 53]. Complication rates with fast-track protocols ranged from 1.5 to 26%. The most reported complications were urinary retention, constipation, motor block, arrhythmia, pneumonia, wound infection/dehiscence, neurological deficit, pain, nausea and vomiting; however, no studies reported an increase in complications associated with fast-track protocols. Conversely, a decrease in adverse events and readmissions associated with the fast-track protocol has been reported in 25% of studies. Only in a few cases was performed a revision surgery mostly for traumatic fracture, screw misplacement and/or removal, graft migration, cerebrospinal fluid leakage, unmanageable pain, and wound infection.

Outcomes and clinical evidence of fast-track protocols

In 46% of studies, general anesthesia by an endotracheal intubation with total intravenous anesthesia (TIVA), using mostly propofol and ketamine, was the usual procedure adopted for spine surgery [15, 19, 20, 32, 34, 35, 37,38,39,40,41,42, 46, 47, 52,53,54,55,56,57,58, 61, 62, 64, 67, 68]. Subsequently, for maintenance of anesthesia, inhalational agents such as sevoflurane, isoflurane and desflurane, or intravenous opioid agents such as sufentanil or remifentanil infusions were used. In 21% of studies, a local anesthesia with anesthetic agents as bupivacaine, lidocaine or ropivacaine was employed [18, 27, 28, 33, 35, 45, 48, 63, 65, 66, 70, 71]. Regarding analgesia management, pain scores were tracked in 30 studies. A significant reduction in pain through visual analog scale (VAS) score, was observed with the fast-track protocols in 40% of studies [18, 21, 23, 27, 31,32,33, 35,36,37,38,39, 41, 42, 45, 47, 48, 55, 60,61,62, 65, 71]. The pain reduction during fast-track pathways were associated to pre-emptive and postoperative analgesia use and to intraoperative local analgesics infiltration (LIA). Several opioid-sparing agents at different concentrations were used for pain relief, specifically, the most used are acetaminophen (1000 mg), gabapentin (300 or 600 mg), pregabalin (75 mg), celecoxib (200 mg) and non-steroidal anti-inflammatory drugs (NSAIDs). Studies demonstrated that this analgesic protocol not only reduced the opioid requirements but also helped to reduce post-operative nausea-vomiting and the risk of complications. Five studies reported little or no difference in pain scores between fast-track and non-fast-track groups, despite a decrease in opioid use after surgery (28%) was detected. A reduction in intraoperative blood loss (25%) and in transfusion rates (5%) with fast-track protocols vs. non-fast-track protocols were also seen in several studies; this aspect is due to the prevention of blood loss and transfusion protocols control as well as thromboprophylaxis (compression stockings or low molecular weight heparin use), maintaining of the body temperature (at 36°-37°, with hot air blanket, fluid warmers or convective warming device) and of fluids and blood pressure. The main blood-saving strategy applied in this review is the TXA use in intraoperative phase, mostly at 10 mg/kg concentration and administered intravenously, orally or topically (1 g). The TXA is an antifibrinolytic medication that stops the breakdown of fibrin clot by inhibiting activation of plasminogen, plasmin, and tissue plasminogen activator. On the other hand, transfusion protocols included control of hemoglobin, platelet and fibrinogen parameters. In addition, a reduction in intraoperative time (19%), catheters and drains removal time (19%), and total health costs (10%) were also detected in these studies. The fast-track elements not only improved the treatment management of the patients, increasing their satisfaction, but also helped the range of motion and return of normal function in all the examined studies that evaluated these parameters (9%). Postoperatively, physiotherapy was applied to increase the range of motion and enhance gait. The improvement in motion and return of function was undoubtedly helped by the early mobilization, by the early nutrition but also by pain management as well as by the information and support given to the patients by the interdisciplinary team, as it has increased their sense of security and satisfaction.

Conclusion

Despite the increasing rates of spine procedures, standardized criteria for pre-, intra- and postoperative management for specific surgeries are lacking. Given the apparent benefits of fast-track programs in other surgical disciplines, implementation of these protocols in spine surgery could be of key importance to reduce LOS, accelerate return of function, minimize postoperative pain, and save costs. Notwithstanding the presence of several preliminary cohort studies that lack of control groups and showed a variability in operations, surgical indications and pathological spine diseases, most reviewed studies demonstrated that fast-track pathways in spine surgery are associated with a shorter LOS and accelerated return to function without increasing rates of complications or readmissions. Furthermore, it was shown that although several of the analyzed fast-track protocols differed in the exact analgesic regimen, the multimodal pain control was a common feature. Given the broad side effect profile of opioid drugs, the use of additional analgesics where possible is encouraged. Another key point of fast-track protocols were the use of TXA, administered either intravenously or orally, that almost eliminated the need for other blood conservation strategies. The reviewed studies also evidenced that early oral intake after surgery is safe and can accelerate the restoration of bowel function and shorten the LOS. Another benefit is that of early mobilization after spinal surgery that led to a reduced rates of infections and medical complications along with a further decrease in mean LOS. In addition to accelerating the return to basic functional level, accelerated walking and rehabilitation also serve to emphasize the patient’s role in recovery.

Despite these promising results, currently, it is difficult to isolate the effect of fast-track elements on patient outcome. It is also difficult to determine whether fast-track would be more successful for specific spine surgeries or pathologies. In fact, current literature for fast-track spinal deformities and AIS is restricted to few clinical studies that are manly retrospective studies with non-randomized data, and initial cohort studies. Furthermore, the different spine procedures vary in expected surgical stress levels and recovery rates, as do the age and patients comorbidity and, to date, these distinctions have not yet been made. Based on these limitations, larger RCTs are mandatory, especially for patients with spinal deformities, to provide robust evidence and establish the efficacy of enhanced-recovery programs for patient populations and procedures within orthopedic spine surgery. Finally, the need for a specific and uniform evidence-based protocol is important to enhance both patient and process outcomes.