Wide-Awake Local Anesthesia No Tourniquet (WALANT) Hand Surgery

Anatomy and Physiology

Tailor the history and physical exam to the pathology requiring repair, and assess for key anatomic landmarks to make the local injection most effective. For example, inject 5 mm proximal to the wrist crease on the median aspect best targets the median nerve in WALANT carpal tunnel release (see 'Techniques' section).[5]

Amides and esters are the two main groups of local anesthetics. WALANT typically utilizes the amides Lidocaine and Bupivacaine. These amides block voltage-gated sodium channels leading to decreased pain sensation and metabolize through the liver.

Epinephrine is used in combination with the amide to provide hemostasis. It accomplishes this by activating alpha-adrenergic receptors causing vasoconstriction of blood vessels. This vasoconstriction also delays lidocaine's absorption, thereby prolonging analgesia and improving lidocaine's safety profile.[8] There is evidence that epinephrine also causes hemostasis via platelet aggregation.[9][10]

A unique advantage of WALANT is that it decreases the risk of adhesion formation due to earlier active participation by the patient, which begins intraoperatively. Collagen formation begins on postoperative day three. Thus it should be a priority to begin supervised exercises after most hand procedures to prevent stiffness and adhesions. Prolonged immobilization causes tendons and soft tissue to adhere to the fracture callous and tendon sheaths, resulting in permanently stiff joints.[11]

Indications

The majority of commonly performed hand procedures can use WALANT successfully.[5] It is ideal for patients with comorbidities that might otherwise preclude them from surgery under sedation (congestive heart failure, obstructive sleep apnea).[1][2] Contraindication to tourniquet is another reason to choose WALANT (i.e., ESRD with an AV-fistula).[1][2]

Poor access to healthcare is an indication for WALANT. Without the need for an operating room or anesthesia team, ambulatory surgical care is possible in locations that are remote or lacking adequate resources.[12][7] Multiple studies have demonstrated that WALANT is consistently cheaper and more efficient to perform than in an operating room when feasible.[13][7][2][11]

The COVID-19 epidemic has highlighted the need for ambulatory surgery to avoid unnecessary exposure. WALANT decreases unnecessary exposure to patients and staff by avoiding both the operating room and overnight stays in the hospital. Without sedation, there are no intubation exposure risks, and fewer staff members are needed to facilitate room turnover. This helps the hospital free up the operating rooms for urgent cases requiring anesthesia.[4][14]

For complex procedures requiring advanced instrumentation and more support staff, such as tendon transfers and multiple fracture fixations, WALANT can easily be performed in the operating room as well.

The three principal benefits of WALANT are patient safety, greater access to surgical needs, and improved intraoperative diagnosis and assessment.[3][7][13][5]

The preoperative benefits of WALANT are improved access to surgical care and workflow. Multiple studies demonstrate decreased wait times from the first consultation to surgery day.[15] Without sedation concerns, patients drive themselves to the facility and eat breakfast beforehand.[16][2] Remote and impoverished areas can accommodate surgeons despite less infrastructure.[7][11] The preoperative phase is shorter, as patients can delay their arrival until 30 minutes before start time. A preoperative workup is not obligatory for safe outcomes. There are fewer procedure cancellations and delays since an anesthesiologist's preoperative clearance is not required. Patients with significant comorbidities like CHF or COPD have less perioperative risk.[3]

Patients can only tolerate tourniquets for durations of no more than thirteen minutes on average.[17][5] Paralysis with a tourniquet can occur in as little as seven minutes.[18] WALANT eliminates the tourniquet risks and brachial plexus blocks. Upper extremity muscles, neurovascular structures, and skin are less likely to be damaged. The surgery can be performed in the upright position if necessary to avoid acute respiratory compromise in patients with obstructive sleep apnea, COPD, or CHF. Injections and the surgery are performed in separate rooms to speed up room turnover, as the injections can be completed in the preoperative area.[19]

WALANT allows the surgeon to make a diagnosis more accurately. Intraoperative assessments are particularly advantageous with flexor tendon repairs, as it is more challenging to gauge tension without patient participation.[20] Gapping is one of the most common complications of flexor tendon repairs, occurring more than 7% of the time.[20] It is linked to tendon rupture (6% prevalence), adhesions, and worsening tendon strength.[21][22] It is critical to maintain a gap of less than 3 mm to minimize poor outcomes. WALANT provides a more accurate assessment of gapping through active patient participation during the repair. This can save a return trip to the surgeon's office, as tendon "bunching" against suture can result in rupture once the active range of motion begins postoperatively.[20][23]

Patient satisfaction and better allocation of resources are the most significant postoperative benefits of WALANT. Studies by Tan (2020) and Rhee (2017) reported that 94% of patients would choose WALANT again in the future. Patients have decreased pain postoperatively in comparison to sedation with a tourniquet. Tahir in 2020 reported that distal radius fractures using WALANT healed more rapidly.[3] WALANT facilitates better communication between the patient and the surgical team, promoting understanding, compliance, and injury prevention postoperatively.[11][2] Less time is spent in the postoperative phase, decreasing costs for the facility and patient.[1][5][2][12] Patients can safely drive themselves home after the procedure.[16] Postoperative opioid consumption is equivalent or decreased with WALANT.[24]

Contraindications

Absolute

• Lack of consent
• Uncooperative (more common with children)[2][3]

Relative[3][7][13][7][3]

• Anxious
• Needle-phobia
• Peripheral vascular disease
• Hypercoagulable
• Lidocaine hypersensitivity
• Ongoing infection
• Polytrauma
• Lack of proper staff, training, facilities
• Language/cultural differences, deaf
• Liver disease[19]
• Anticoagulants* (controversial)
• Preference for general anesthesia
• Inability to lay supine (history of back pain, OSA, et al.)

Equipment

Procedure rooms should be equipped with adequate lighting and have a headlamp available. Position an ergonomic chair appropriately for the injection to minimize a vasovagal response.[5][2] Pillows are helpful for chronic back and neck pain. Resuscitation equipment should be on hand to perform BLS or ACLS if needed and smelling salts for syncopal events. Sterile equipment includes instrument peel packs, gloves, towels, chlorhexidine/iodine solutions.[2] A smaller needle size (25 to 27 gauge) is ideal for two reasons: it is less painful penetrating the skin and prevents high injection rates of acidic lidocaine uncomfortable for the patient.[1][11]

The most common analgesic-hemostasis mixture is 1% lidocaine with 1:100,000 epinephrine.[2][5][1] Other lidocaine-epinephrine ratios have also shown efficacy in tendon repair of the wrist (1:400,000) and with fracture manipulation (1:1,000,000).[1][20] Optional 8.4% bicarbonate mixed in 1 ml:10 ml fashion with the lidocaine-epinephrine solution functions well as a buffer solution to diminish lidocaine acidity during the injection.[5][25] Bupivacaine can be added to the lidocaine-epinephrine mixture for cases with durations greater than 2.5 hours.[5] Phentolamine reversal should always be available and given as 1 g diluted in 1 to 10 ml of 0.9% normal saline.[13]

Personnel

Well-trained personnel must facilitate all three perioperative phases of WALANT surgery to maximize workflow and patient outcomes.[2] The interdisciplinary team includes the surgeon, a "distractive anesthesia" team member to minimize patient anxiety, scrub tech, first assist, circulating nurse, and hand therapist.[3][2][11]

Preparation

Patients should arrive at least thirty minutes before the procedure start time. Assume patients are unfamiliar with medical terminology and anxious about being awake. Therefore all communication should be through simple language.[2] Given the COVID epidemic, minimize exposures through PPE at all times, avoid overlap of patients in waiting rooms and staff only as necessary.[4]

Administer lidocaine-epinephrine approximately thirty minutes before incision time.[2][13][19] Move the patient into the procedure room fifteen minutes beforehand.[2] Have 1 g phentolamine in 10 ml of 0.9% normal saline available if epinephrine reversal is needed.[13] Utilize bicarbonate buffer for procedures requiring more local anesthetic.[11] Cefazolin is the standard perioperative antibiotic prophylaxis.[1] Keep extra 1% lidocaine with epinephrine available if pain control or hemostasis is initially inadequate.[3] Research has found a high safety profile in measuring vital signs, EBL, and VAS scores in 10-minute intervals throughout the procedure. Surgeons instruct patients on intraoperative testing as well as education on post-op care.[3] Hand therapists can often assist with splint placement at the end of the procedure.[2]

Vital signs should be taken every thirty minutes for the first few hours postoperatively.[3] A typical discharge pain regimen includes PO tramadol 37.5/325mg acetaminophen BID combination for ten days and calcium supplements.[3][1] In general, most post-operative rehabilitation involves early protective movement, and patients should avoid doing anything painful without a hand therapist present.[11]

Technique or Treatment

The three main principles of WALANT are pain control with lidocaine, bleeding control with epinephrine, and anxiety control with technique and ambiance (Ilyas, FORE lecture 2018).

Inject the patient while they sit upright to avoid a potential vasovagal response.[5] Keep the needle as still as possible, and inject at an angle perpendicular to the skin.[11] Move the extremity towards the needle instead of pushing the needle into the skin to decrease discomfort. Inject up to 10 ml just beneath the skin and antegrade, maintaining at least one centimeter of local wheel ahead of the advancing needle tip at all times. Reinsert the needle into areas already numbed for repeat injections. When done correctly, patients should only feel pain with the initial injection.[11]

• Carpal tunnel release - 10 ml injection 5 mm proximal to wrist crease and 5 mm ulnar to the median nerve, and an additional 10 ml injected deep to the incision site
• Trigger finger - 4 ml injection into subcutaneous tissue just deep to the incision site. Avoid injection into the sheath.
• Finger sensory block - 2 ml injection into the dorsal or volar aspect of proximal phalanx distal to finger-palm crease[5]
• Metacarpal fractures - 40 ml circumferentially around metacarpal
• Dupuytren's contracture - 10 ml injection into palm, 2 ml into proximal phalanx, 2 ml middle phalanx[5]
• ORIF distal radius - 5 ml injection into distal radius fracture. 10 ml into volar or dorsal distal radius. Use a more concentrated 1:40,000 1% lidocaine-epinephrine as it is a procedure that requires more hemostasis. For volar plating, inject 5 l into the pronator quadratus. For dorsal plating, inject 5 ml beneath the extensor retinaculum[1]

Complications

The most common adverse reaction associated with WALANT is fainting secondary to a vasovagal response.[5] Another common reaction is increased anxiety in patients who fear being awake for the procedure. "Jitters" also can infrequently occur with lidocaine.[2] Otherwise, few adverse effects exist for WALANT.

A common myth associated with WALANT is that there is a high risk of digital ischemia with epinephrine use. This concern originated from a study using procaine-epinephrine instead of lidocaine for analgesia. Procaine has a higher incidence of digital ischemia due to its significantly lower pH than lidocaine or bupivacaine.[20] Multiple studies have reported that lidocaine-epinephrine in controlled doses is safe to use in the fingers.[20][26][27][12][25]

Epinephrine-induced cardiac ischemia is a rare complication of WALANT.[28] Lidocaine seldom causes significant adverse effects. However, seizures and altered mentation have been reported with intravascular administration.[29][5] Intravascularly administered bupivacaine-induced cardiotoxicity and death are also exceedingly rare. Unlike lidocaine, the analgesic effects of bupivacaine wear off before the paresthesia.[5]

Clinical Significance

WALANT hand surgery enhances patient safety by eliminating the risks associated with sedation and tourniquet. Its minimalistic approach makes it ideal in an ambulatory setting, minimizing healthcare disparities through better healthcare access. Patients living far from the hospital or in a healthcare-poor region can have access to surgical care. Other benefits include decreased patient cost, less time spent out of work, and less time waiting to schedule surgery.[2][11][3][7][12]

In times of the COVID-19 epidemic, WALANT provides an opportunity for patients to receive surgical care without taking up valuable OR time for emergent cases. Additionally, it decreases exposure between patients, hospital, and staff as it can be performed outside the operating room.[4][14] Regarding the opioid epidemic, WALANT has shown to have at least equivalent results in opioid consumption postoperatively compared with general sedation in an operating room.[1][24]

Enhancing Healthcare Team Outcomes

WALANT is most effective when set protocols are in place, and a multi-disciplinary approach is utilized. Staff well versed in guiding patients through the preoperative, operative, and recovery phases of surgery day in an unfamiliar ambulatory setting will maximize work efficiency and minimize anxiety.[2] Intraoperatively, a staff member in charge of providing "distracting anesthesia" improves patient satisfaction and workflow.[3] Hand therapists further promote a team atmosphere and assure the patient that they are supported.[11]

Nursing, Allied Health, and Interprofessional Team Interventions

Wide-awake Local Anesthesia No Tourniquet (WALANT) is an alternative to general anesthesia and tourniquet for undergoing surgery. General anesthesia is where the anesthesiologist sedates the patient (induces sleep) before the surgery starts in the operating room to reduce pain sensation. A tourniquet is a device that squeezes the arm to control bleeding. Instead, WALANT uses only tiny doses of lidocaine to decrease pain and epinephrine to minimize bleeding. Typically the injections take place thirty minutes before surgery starts.

The patient remains awake throughout the procedure. The surgeon asks the patient for feedback and to perform specific movements that help improve the repair. This technique is especially beneficial for patients with tendon injuries. Often a hand therapist will be present to assist with range-of-motion exercises and discuss future rehabilitation plans. Since the patient is awake, there are more opportunities to ask the surgeon questions and learn about the procedure.

WALANT can easily be performed in a surgery center or even in the surgeon's office. On the day of surgery, patients can have breakfast and drive themselves to their procedure. For patients that have severe medical conditions like congestive heart failure, WALANT may be a better alternative. Other benefits include more flexible scheduling and affordability. WALANT effectively treats many conditions affecting the hand, such as carpal tunnel syndrome, trigger finger, and wrist fractures.