Nerve Blocks

Regional blocks can reduce postoperative pain and opioid requirements when their coverage matches the operation. Select the technique with the anesthesia team using the incision, anticipated visceral pain, patient anatomy, anticoagulation, existing neurologic deficits and available monitoring. The 2026 ASA guideline supports fascial plane blocks within multimodal analgesia for adult open abdominal, retroperitoneal and pelvic surgery, and for minimally invasive abdominal surgery. It does not rank ESP, QL and TAP against one another.^[1]

This is the block-selection and safety workflow. Use Local Anesthetics for formulation-specific doses and Liposomal Bupivacaine for its label and comparative evidence. Analgesia covers systemic treatment and postoperative monitoring; Anesthesia covers the anesthetic plan.

Local Anesthetic Pharmacology

Plan the total exposure

Before injection, agree on the agent, concentration, total milligrams, sites and timing with everyone administering local anesthetic. Include bilateral blocks, wound infiltration, urethral or mucosal preparations, catheters and any IV lidocaine. Toxicity is additive; changing agents or dividing injections between surgeon and anesthesiologist does not reset the dose allowance.^[2][3]

A generic mg/kg ceiling is not a guarantee of safety. The product, route, vascularity of the site, age, body size, hepatic/cardiac function and repeat dosing matter. Choose the lowest effective exposure and follow the actual product label and institutional protocol. Adult block volumes must not be transferred to children.^[2][3]

Mixing and adjuvants

Routine lidocaine–bupivacaine mixing is not an established safety strategy; the current bupivacaine label does not recommend mixing or intercurrent use of other local anesthetics because clinical data are insufficient. Any planned combination needs a specific compatibility and cumulative-dose assessment. Liposomal bupivacaine has additional restrictions below.^[3]

For bicarbonate, steroids, clonidine or dexmedetomidine, verify the agent, route, preservative content and compatibility in a pharmacy/anesthesia protocol. A drug used intravenously and the same drug injected around a nerve are different interventions; efficacy and duration cannot be assumed to transfer between routes or blocks.

For IV lidocaine, follow the separation intervals and monitoring in Analgesia: a block or infiltration must be coordinated with the infusion, including longer restrictions after liposomal bupivacaine.

Injection Best Practices

• Confirm consent, procedure, side, baseline sensory/motor findings, anticoagulants and the rescue plan. Deep blocks require assessment under the applicable regional-anesthesia antithrombotic rules.
• Use aseptic technique and appropriate anatomical or ultrasound localization. Ultrasound lowers LAST risk but does not eliminate intravascular injection or nerve injury.
• Aspirate before incremental injections; negative aspiration is not proof of correct placement. Inject slowly, observe spread when using ultrasound and stop if placement is uncertain, injection is unexpectedly painful or resistance is abnormal.
• Use appropriate cardiovascular, respiratory and consciousness monitoring during and after injection. LAST can be delayed; the ASRA advisory recommends at least 30 minutes of close monitoring after potentially toxic doses, with 30–45 minutes specifically discussed for truncal blocks.
• Keep oxygen, resuscitation equipment, 20% lipid emulsion and the ASRA checklist immediately available. An office block needs the same capacity to recognize and initially manage toxicity as its drug exposure warrants.^[2][3]

For awake infiltration, explain the sequence, use a suitable small needle, inject gradually and allow anesthetic onset before proceeding. Buffering or warming should follow a validated preparation protocol; neither replaces accurate placement or dose control.

Local Anesthetic Systemic Toxicity (LAST)

Neurologic symptoms may include circumoral numbness, tinnitus, altered consciousness or seizures. Cardiovascular toxicity can occur without a preceding neurologic warning. Stop local anesthetic, summon help and use the ASRA LAST checklist.^[2][4]

The posted 2020 checklist specifies:^[4]

• Support the airway; prefer benzodiazepines for seizures. Consider lipid emulsion early.
• 20% lipid, under 70 kg: bolus approximately 1.5 mL/kg over 2–3 minutes, then 0.25 mL/kg/min. Over 70 kg: approximately 100 mL over 2–3 minutes, then approximately 250 mL over 15–20 minutes.
• If unstable, repeat the bolus and double the infusion. Continue infusion for more than 15 minutes after hemodynamic stability; maximum lipid dose 12 mL/kg.
• Resuscitation differs from standard ACLS: use smaller epinephrine doses, starting below 1 microgram/kg; avoid vasopressin, beta-blockers, calcium-channel blockers and local-anesthetic antiarrhythmics. Consider extracorporeal support for refractory collapse.
• Observe at least 2 hours after seizure or 4–6 hours after cardiovascular instability, with further care determined after cardiac arrest.

Fascial Plane Blocks for Abdominal and Pelvic Reconstruction

Transversus Abdominis Plane (TAP) Block

The target is the plane between internal oblique and transversus abdominis. Lateral and subcostal approaches cover different portions of the abdominal wall; select the approach to the actual incision and extraction site. TAP primarily addresses somatic abdominal-wall pain and does not provide reliable visceral analgesia.^[1][5]

Quadratus Lumborum (QL) Block

Specify the approach: anterior QL targets the QL–psoas interface; posterior QL lies behind the muscle; lateral QL is at its lateral fascial border. These are distinct injections. Spread and effect vary, and QL must not be presented as a guaranteed visceral block or categorically superior to TAP.^[1][5]

Erector Spinae Plane (ESP) Block

The target is deep to the erector spinae muscles at the transverse process. Select the vertebral level for the surgical territory. Paravertebral spread and visceral analgesia are variable; a technically successful ESP block does not replace a rescue plan.^[1][5]

Rectus Sheath Block

The target is between rectus abdominis and its posterior sheath where that sheath is present. It is an option for midline somatic incisional pain. Coverage depends on injection level and spread; it does not cover all lateral ports or visceral pain.^[1][5]

What the comparative evidence supports

The ASA 2026 guideline's recommendations concern pain and/or opioid reduction in the first 24 hours, with moderate evidence for adult abdominal surgery. Its minimally invasive nephrectomy/urology subgroup found modest pain reductions and lower opioid use; the evidence does not establish a single best block for every reconstruction.^[1]

Micali et al. (2024) studied 190 patients prospectively: 93 received TAP and 97 ESP. Allocation reflected clinician choice, and the regimens differed—ESP included dexmedetomidine, whereas TAP included perioperative morphine. Lower pain and rescue use in the ESP group are observational associations, not randomized proof of ESP superiority. There was no QL group. These data cannot support an ESP ≥ QL > TAP hierarchy.^[6]

Peripheral Blocks Specific to Urology

Pudendal Nerve Block

Pudendal branches supply the perineal and external-genital territory and participate in somatic sphincter function. A pudendal block may be useful for the perineal component of urethroplasty, perineal urethrostomy, AUS placement or fistula repair, with additional anesthesia for deeper pelvic work, abdominal incisions or flap donor sites. It is not a reliable block of all bladder, trigonal or upper-vaginal visceral sensation.

Ischial-spine approaches and Alcock-canal approaches are distinct. Specify the target and guidance method rather than applying a single needle direction or volume to both. Bendtsen's original canal technique report involved only three patients and two cadavers; it established feasibility, not comparative superiority or freedom from sacral plexus spread.^[7]

Urogynecology — the Khalil RCT

Khalil et al. randomized 57 women undergoing anterior/posterior colporrhaphy to nerve-stimulator-guided pudendal block or general anesthesia. Pain and analgesic consumption were lower with block; 3.6 versus 12.2 days referred to return to normal daily activity. This small trial supports an option for selected repairs, not a universal primary anesthetic for prolapse surgery or a recovery prediction for older/comorbid patients.^[8]

Dorsal Penile Nerve Block

This targets the paired dorsal penile nerves. Subpubic, ultrasound-guided and perineal approaches require different anatomical localization; avoid the adjacent vessels and assess the ventral/frenular territory, which may need supplementary infiltration. Applications include circumcision, selected penile procedures, paraphimosis reduction and analgesia during priapism treatment.

A 33-child hypospadias RCT reported first analgesic requirement at approximately 32 versus 21 hours for ultrasound-guided dorsal penile versus nerve-stimulator-guided pudendal block. These are study-specific time-to-rescue results, not expected durations for every patient or proof that ultrasound is mandatory for all penile surgery.^[9]

Penile Ring Block

Circumferential subcutaneous infiltration targets penile skin and can supplement a dorsal block. Avoid a large-volume, high-pressure injection in tissue with uncertain perfusion. Plain local anesthetic is commonly selected. If epinephrine is considered, assess the exact product and vascular risk: current bupivacaine/epinephrine labeling calls for carefully restricted quantities in the penis and warns of ischemic injury. Apply that product-specific precaution and assess tissue perfusion before use.^[3]

Spermatic Cord Block

Cord and surrounding-tissue blockade can supplement anesthesia for selected scrotal-content operations. The genital branch of the genitofemoral nerve travels with the cord; the ilioinguinal nerve runs nearby in the inguinal canal, outside the cord's internal contents. Skin innervation is broader, so a cord block may need separate cutaneous or ilioinguinal coverage. Identify the vas and vessels and place anesthetic around the intended neural tissue, not into those structures.^[10]

For isolated unilateral chronic scrotal content pain, AUA 2025 permits diagnostic cord and/or ilioinguinal block as expert opinion. Relief can inform counseling about denervation, but does not guarantee surgical success or exclude other pain generators.^[11]

Ilioinguinal / Iliohypogastric Block

These nerves supply parts of the lower abdominal wall and inguinal/genital skin. Ultrasound-guided targeting is usually in the internal oblique–transversus abdominis plane, not between external and internal oblique. It can complement inguinal or Pfannenstiel incisional analgesia; it does not anesthetize the entire testis, scrotum or vulva.^[5][10]

Periurethral Block (Female)

This is local infiltration, used with topical anesthesia in selected office urethral procedures, particularly bulking. Choose preparation, placement and monitoring from the actual procedure and device instructions. Count topical and injected anesthetic together.

The bulking material is not a local anesthetic. Bulkamid is polyacrylamide hydrogel and water; analgesia is a separate intervention. The FDA-hosted physician instructions describe separate anesthetic preparation and prohibit mixing the hydrogel with other substances. Routine cystoscopy, intradetrusor Botox and urethral procedures have different pain sources and do not all require a periurethral block.^[12]

Uterosacral / Cervical and Paracervical Blocks

Local injection around the cervix/uterosacral region is a separate technique from pudendal blockade. In Barba's 40-woman nonrandomized pilot, patients chose whether to receive ropivacaine plus clonidine alongside general or spinal anesthesia. Some pain measurements improved, but rescue-opioid use and hospital stay did not differ significantly. This does not establish a universal additive regimen or a replacement for the primary anesthetic.^[13]

Product restrictions matter: EXPAREL is contraindicated for obstetrical paracervical anesthesia. A gynecologic infiltration report does not override that contraindication.^[14]

Liposomal Bupivacaine (Exparel) — the Evidence

The current label distinguishes local infiltration from its established adult regional indications: interscalene, popliteal sciatic and adductor canal blocks. Pudendal, penile, spermatic-cord and TAP regional use are not established labeled indications. Do not transfer an approved limb-block dose to a bilateral GU block or promise 72 hours of analgesia.^[14]

Avoid additional local anesthetic within 96 hours after EXPAREL, while following the label's specific permitted concurrent bupivacaine regimens and compatibility rules. It must not be admixed with lidocaine or other non-bupivacaine local anesthetics; administration after local lidocaine requires at least 20 minutes. Detailed dosing and the bupivacaine-HCl mixing limit remain on the pharmacology hub.^[14]

Ilfeld's 2021 review found clinically meaningful statistically significant benefit in 4 of 36 infiltration-versus-standard-agent trials; that denominator is a subset of its 76 trials. Comparative results depend on the operation, comparator, technique and outcome. Use the hub's subsequent evidence to judge incremental benefit and cost; neither a premium product nor a continuous catheter is universally superior.^[15]

Practical Block Selection by Reconstructive / Functional Operation

These are options to discuss, not mandatory protocols or dosing orders.

Surgical territory	Options	Coverage to confirm
Abdominal reconstruction: augmentation, channel creation, ureteral repair/diversion	Incision-matched TAP, rectus sheath, QL or ESP; selected neuraxial techniques	Midline versus lateral/extraction-site pain, visceral pain, cumulative local anesthetic
Perineal urethroplasty, AUS or fistula repair	Pudendal plus local infiltration as appropriate	Deep dissection, abdominal component and gracilis/other donor site
Penile surgery	Dorsal penile and/or ring block	Ventral/frenular, proximal and deeper operative territories; perfusion
Scrotal-content or inguinal surgery	Cord, skin infiltration and/or ilioinguinal/iliohypogastric block	Cutaneous versus cord/testicular pain and expected traction
Vaginal or vulvar repair	Procedure-specific pudendal, local or other regional technique	Upper vaginal/visceral and anterior vulvar territories
Office urethral bulking	Topical anesthesia with procedure-specific local infiltration	Patient comfort and separate device/anesthetic preparation

Confirm block effect before relying on it, retain rescue analgesia, and give instructions about residual numbness, weakness, delayed toxicity and whom to contact after discharge.

References

1. Joshi GP, Mariano E, Elkassabany NM, et al. "2026 American Society of Anesthesiologists Practice Guideline on Perioperative Pain Management Using Local and Regional Analgesia for Cardiothoracic Surgeries, Mastectomy, and Abdominal Surgeries." Anesthesiology. 2026;144:19–43. doi:10.1097/ALN.0000000000005790.

2. Neal JM, Barrington MJ, Fettiplace MR, et al. "The Third American Society of Regional Anesthesia and Pain Medicine Practice Advisory on Local Anesthetic Systemic Toxicity: Executive Summary 2017." Reg Anesth Pain Med. 2018;43:113–123. doi:10.1097/AAP.0000000000000720.

3. Pfizer. Bupivacaine hydrochloride with/without epinephrine: prescribing information. Current label. Accessed September 12, 2026.

4. ASRA Pain Medicine. Local Anesthetic Systemic Toxicity Checklist. Version 2020. Checklist.

5. El-Boghdadly K, Wolmarans M, Stengel AD, et al. "Standardizing nomenclature in regional anesthesia: an ASRA-ESRA Delphi consensus study of abdominal wall, paraspinal, and chest wall blocks." Reg Anesth Pain Med. 2021;46:571–580. doi:10.1136/rapm-2020-102451.

6. Micali M, Cucciolini G, Bertoni G, et al. "Analgesic Strategies for Urologic Videolaparoscopic or Robotic Surgery in the Context of an Enhanced Recovery after Surgery Protocol: A Prospective Study Comparing Erector Spinae Plane Block versus Transversus Abdominis Plane Block." J Clin Med. 2024;13:383. doi:10.3390/jcm13020383.

7. Bendtsen TF, Parras T, Moriggl B, et al. "Ultrasound-Guided Pudendal Nerve Block at the Entrance of the Pudendal (Alcock) Canal: Description of Anatomy and Clinical Technique." Reg Anesth Pain Med. 2016;41:140–145. doi:10.1097/AAP.0000000000000355.

8. Khalil I, Itani SE, Naja Z, et al. "Nerve stimulator-guided pudendal nerve block vs general anesthesia for postoperative pain management after anterior and posterior vaginal wall repair: a prospective randomized trial." J Clin Anesth. 2016;34:668–675. doi:10.1016/j.jclinane.2016.07.024.

9. Aksu C, Akay MA, Şen MC, Gürkan Y. "Ultrasound-guided dorsal penile nerve block vs neurostimulator-guided pudendal nerve block in children undergoing hypospadias surgery: A prospective, randomized, double-blinded trial." Paediatr Anaesth. 2019;29:1046–1052. doi:10.1111/pan.13727.

10. USRA. Inguinal Canal Block. Anatomy and ultrasound chapter. Accessed September 12, 2026.

11. AUA. Diagnosis and Management of Male Chronic Pelvic Pain. 2025; statement 12. Guideline.

12. FDA. Bulkamid Urethral Bulking System. PMA P170023, 2020. Device composition; physician instructions, preparation and mixing precautions.

13. Barba M, Cola A, De Vicari D, et al. "Enhanced recovery after surgery (ERAS) in prolapse repair: A prospective study on pre-emptive uterosacral/cervical block." Int J Gynaecol Obstet. 2024;166:1240–1246. doi:10.1002/ijgo.15483.

14. Pacira. EXPAREL: prescribing information. DailyMed. Accessed September 12, 2026.

15. Ilfeld BM, Eisenach JC, Gabriel RA. "Clinical Effectiveness of Liposomal Bupivacaine Administered by Infiltration or Peripheral Nerve Block to Treat Postoperative Pain." Anesthesiology. 2021;134:283–344. doi:10.1097/ALN.0000000000003630.