ERAS in UBE

#The ERAS Triad: Preoperative · Intraoperative · Postoperative

The most important principle of ERAS is the bundle approach. No individual element is effective in isolation; synergy emerges only when the elements of the preoperative, intraoperative, and postoperative phases operate together. "Cherry-picking" — selectively applying only one or two elements — is the most common misstep that misses the essence of ERAS.

The ERAS® Society lumbar fusion consensus proposes 22 items and 28 recommendations. Considering the surgical profile of UBE, the core elements among them can be organized as follows.

Preoperative (9 items)
Patient education and expectation setting, nutritional assessment and optimization, smoking cessation, anemia correction, glucose optimization, fasting protocol with carbohydrate loading, premedication minimization, antimicrobial prophylaxis, thromboprophylaxis planning.

Intraoperative (11 items)
Minimally invasive surgical approach, multimodal anesthesia (opioid-sparing), restrictive fluid management, normothermia maintenance, antifibrinolytic agents, local wound infiltration, selective drain use, antibiotic prophylaxis, lung-protective ventilation, glucose control, prophylactic PONV management.

Postoperative (6 items)
Early mobilization, multimodal analgesia with opioid-sparing strategy, early oral intake, early urinary catheter removal, DVT prophylaxis continuation, structured discharge criteria.

The sections that follow review the core elements of each phase from the UBE perspective.

#Preoperative Phase

Patient education & expectation setting
The effect of ERAS is greatest when the patient shares the recovery timeline and participates actively. In the preoperative clinic, UBE patients are walked through the admission schedule, the expected character of postoperative pain, the timing of first ambulation (typically within 2–4 hours), the timing of resuming oral intake, and the discharge criteria. This step carries virtually no additional cost yet exerts a meaningful effect on patient satisfaction and LOS.

Nutritional assessment & optimization
Nutritional risk is screened on the basis of albumin, prealbumin, and BMI. Because malnutrition is a risk factor for delayed wound healing, increased infection risk, and prolonged recovery, preoperative nutritional support is considered in high-risk patients.

Carbohydrate loading
Traditional NPO from midnight is no longer recommended under ERAS. The ERAS Society guideline recommends allowing clear fluids up to 2 hours before surgery and using a carbohydrate-rich drink. Carbohydrate loading reduces insulin resistance and decreases postoperative nausea and fatigue. The decision is individualized, however, in patients with diabetes or delayed gastric emptying.

Smoking cessation, anemia correction, glucose optimization
Smokers are advised to stop smoking at least 4 weeks before surgery. Preoperative anemia (Hb < 12 g/dL in females, < 13 g/dL in males), which increases transfusion risk and postoperative complications, is corrected with iron supplementation. In patients with diabetes, HbA1c < 7.5% and perioperative glucose of 140–180 mg/dL are the targets.

Same-day admission
For single-level UBE decompression, same-day admission (or an outpatient setting) is feasible. A UCLA cohort study of 84 patients found no difference in complications between outpatient and inpatient biportal endoscopy, while postoperative VAS-back and ODI at 5–8 weeks were significantly better in the outpatient group. Patients with ASA ≥ 3, insufficient social support, or multilevel fusion are, however, selected more conservatively.

#Intraoperative Phase

UBE itself is a key intraoperative ERAS element
The first intraoperative recommendation in the ERAS Society guideline is "minimally invasive surgical approach when feasible". UBE fulfills this recommendation in the most direct way possible. In the meta-analysis of 12 studies and 981 patients, ULIF demonstrated reduced EBL, shortened LOS, and improved 1-month VAS and ODI compared with conventional MI-TLIF and PLIF, with no differences in fusion rate or complication rate. Choosing UBE is therefore itself the first step of the ERAS bundle.

Multimodal anesthesia (opioid-sparing)
Preincision multimodal analgesia is initiated: acetaminophen 1g IV + an NSAID (e.g., ketorolac 30 mg) + a gabapentinoid is a standard combination. On the anesthesia side, TIVA or propofol-based anesthesia lowers opioid dependence. Intraoperative opioid is titrated to surgical stimulation at the minimum effective dose.

Restrictive fluid management
ERAS recommends goal-directed restrictive fluid therapy. Because UBE uses large-volume saline irrigation intraoperatively, systemic IV fluids must be managed even more restrictively. In consultation with the anesthesia team, hourly maintenance fluid is minimized and hemodynamic changes are corrected with vasopressors when needed.

Antifibrinolytic agent (TXA)
The perioperative use of tranexamic acid in spine surgery has been shown — in a systematic review of 18 studies and 2,045 patients — to reduce intraoperative and postoperative blood loss without an observed increase in thromboembolism risk. As discussed in the hemostasis strategy section, a combination of a pre-op IV bolus of 10–15 mg/kg and topical application just before closure is the most practical regimen.

Local wound infiltration
Just before closure, bupivacaine or ropivacaine is infiltrated around the portals. When available, liposomal bupivacaine provides a more prolonged analgesic effect. This simple step meaningfully reduces opioid consumption in the first 24 postoperative hours.

Maintaining normothermia
Hypothermia (core temperature < 36°C) is a risk factor for SSI, coagulopathy, and altered opioid metabolism. Perioperative normothermia is maintained with forced-air warming, warmed IV fluids, and — where feasible — warmed irrigation saline.

Selective drain use
Routine drain placement is not recommended under ERAS. For UBE decompression-only cases, closure is often possible without a drain. In fusion cases or bilateral decompression cases, drains are placed selectively, following the indications discussed in the hemostasis strategy section.

#Postoperative Phase

Early ambulation
This is the single most powerful element of the postoperative phase of ERAS. In the UBE-ULBD ERAS cohort study, the ERAS group achieved significantly earlier first ambulation than the traditional group. For straightforward UBE decompression, an attempt at ambulation within 2–4 hours after surgery is the standard target. Sharing this explicit numeric target with PACU and ward staff is more effective than a vague "as tolerated" order.

Multimodal analgesia (opioid-sparing)
The default for postoperative pain management is scheduled acetaminophen and an NSAID (when appropriate). Opioids are not part of the baseline regimen; they are reserved as rescue agents for breakthrough pain. To achieve the visible opioid-sparing effect, acetaminophen and NSAIDs must be administered on a schedule, not on a PRN basis.

Adjuncts such as gabapentinoids, low-dose ketamine infusion, and dexmedetomidine may be used selectively. NSAID selection takes into account renal function, history of GI bleeding, and concerns about osseointegration in fusion cases, and is decided case by case.

Early oral intake
Absent PONV, a sip of water is attempted within 2–4 hours after surgery, followed by gradual advancement of food. The traditional practice of "NPO until passing gas" is not evidence-based in spine surgery.

Early urinary catheter removal
The Foley catheter is removed on the first postoperative morning by default. Prolonged catheterization is a risk factor for UTI, delayed ambulation, and urinary retention. In single-level decompression cases, intraoperative catheterization itself may often be omitted.

DVT prophylaxis & PONV prevention
Mechanical prophylaxis (IPC, sequential compression devices) is applied to all patients. Chemical prophylaxis (LMWH, etc.) is decided on the basis of individual risk (Caprini score, etc.). For PONV, dual-agent prophylaxis with ondansetron and dexamethasone is standard.

Structured discharge criteria
ERAS recommends discharge upon meeting explicit criteria, not "discharge when ready". The baseline criteria are: (1) pain controlled on oral medication, (2) independent ambulation, (3) tolerating an oral diet, (4) voiding without retention, (5) no acute neurologic deficit, and (6) understanding of the postoperative instructions and follow-up plan.

#Common Pitfalls

(a) Cherry-picking ERAS elements
Recognition: A team claims to "practice ERAS", but in reality only one or two elements — such as carbohydrate loading or early ambulation — are actually in place. The expected outcome improvements fail to materialize.

Recovery: (1) Codify the ERAS Society 22-item checklist as an institutional protocol. (2) Define the minimum essential elements for each phase. (3) Build a standardized pathway applied to all patients to reduce variability. (4) Ensure that the multidisciplinary team — surgeon, anesthesia, nursing, pharmacy, and PT — shares the protocol.

(b) Cascade of failed pain control
Recognition: Multimodal analgesia is incompletely applied, postoperative VAS remains high, the patient refuses ambulation, LOS is prolonged, and increased opioid use brings on secondary complications such as PONV, constipation, and urinary retention.

Recovery (= prevention): (1) Make preincision multimodal analgesia routine. (2) Schedule acetaminophen and NSAIDs on the clock; use opioids only as PRN rescue. (3) Set a numeric pain target (e.g., VAS ≤ 3) from the PACU onward. (4) If pain is not controlled, escalate analgesia first rather than forcing ambulation.

(c) Patient selection mismatch
Recognition: An outpatient or early-discharge protocol is applied uniformly across patients, resulting in readmissions, ER visits, or safety events.

Recovery: (1) Restrict outpatient/early-discharge candidates to ASA 1–2, with adequate social support, in single-level cases. (2) Default to an inpatient pathway for patients who are ASA ≥ 3, elderly with frailty, undergoing multilevel fusion, or on anticoagulants. (3) Perform explicit individual risk stratification in the preoperative clinic. (4) Communicate the follow-up plan and emergency contact information clearly before discharge.

#Pearls for the First Cases

If working portal triangulation sets the geometry of the working zone, fluid management determines its hydrodynamics, and hemostasis provides the final layer of safety, then ERAS is the framework that translates all of that surgical excellence into the patient's recovery. Modern UBE practice is complete when these four pillars — geometry, hydrodynamics, safety, and recovery — operate together.

#Author Note

This article summarizes Enhanced Recovery After Surgery (ERAS) principles as applied to unilateral biportal endoscopic (UBE) spine surgery and does not substitute for individual clinical judgment. Specific perioperative measures — including fasting protocols, fluid management, analgesic regimens, ambulation timing, and discharge criteria — should be individualized based on patient factors, institutional resources, multidisciplinary team consensus, and surgeon experience.