Pudendal anesthesia
| Pudendal anesthesia | |
|---|---|
 Approximate area of "saddle anesthesia" seen from behind (yellow highlight) | |
| Other names | Saddle block |
| Specialty | anaesthesiology |
Background
Pudendal anesthesia (pudendal
Procedure
Overall, the procedure involves injecting a local anesthetic drug (e.g. lidocaine or bupivicaine) with a 20 gauge spinal needle near the pudendal nerve in order to provide pain relief.[1][2] Lidocaine is usually preferred for a pudendal block because it has a longer duration than chloroprocaine which usually lasts less than one hour.[5] The procedure can be done without imaging guidance, but fluoroscopy or ultrasound can be used.[2][4] Ultrasound is preferred because there is no exposure to radiation, it is readily available, and it offers real-time guidance for needle insertion.[4] There are different anatomical approaches for which the procedure can be performed such as; transvaginal, transperineal, or perirectal.[1] The aim is to block the nerve as it enters the lesser sciatic foramen, which anatomically is just below the and inwards from the attachment of the sacrospinous ligament to the ischial spine of the pelvic bone.[2] The transvaginal approach is used for obstetric and gynecological procedures. The ischial spines are identified by palpation of the vaginal walls and the needle is advanced through the vaginal wall.[2] The transperineal approach more commonly requires image guidance and is used for anorectal and urologic procedures, and treatment of pudendal neuralgia. For both the transperineal and the perirectal approach the ischial spines are identified through palpation of the rectal walls.[2] The perirectal approach requires the use of a nerve simulator that if placed in the correct position will cause the external anal sphincter to contract. This helps confirm the correct positioning of the needle as it is advanced laterally to the rectum.[2]
Indications
Obstetrics
A pudendal nerve block has been historically used to provide pain relief during child birth. It is generally used as a second line option, when neuraxial (i.e. epidural) anesthesia is not available or contraindicated.
Pudendal neuralgia
Chronic pain that arises in the
Urological surgery
The use of the pudendal nerve block is being explored in pediatric urologic procedures such as circumcision. It allows pain relief from the perineum to the end of the penis.[10] It lowers post operative pain and the need for opioids just as it does for MIGS.[9][10]
Anorectal surgery
A common anorectal surgery that utilizes pudendal anesthesia is a
Contraindications
- Allergy to the local anesthetic drug[2]
- Local infections at the site of injection or systemic infection[2]
- Blood coagulation disorders[2]
- Prior surgery to the area that changed the anatomy[2]
Complications
Common
- Discomfort at the site of injection[2]
Uncommon
- Pudendal nerve damage[2]
- Sciatic nerve damage[12]
- Bleeding[2] or hematoma[8]
- Infection[2]
- Injury to organs near the pudendal nerve (e.g bladder, rectum)[2]
- Injury to pudendal artery [2]
- Injection of local anesthesia into artery leading to systemic toxicity[2]
- Urinary retention[12]
- Urinary or fecal incontinence[12]
References
- ^ a b c d e f Chowdhury, S; Gray, G; Trescot, A (2015). Atlas of Pain Medicine Procedures. McGraw Hill.
- ^ PMID 31855362, retrieved 2023-11-13
- ^ Carrera, A; Lopez, AM; Sala-Blanch, X; Kapur, E; Hasanbegovic, I; Hadzic, A (2017). Hadzic's Textbook of Regional Anesthesia and Acute Pain Management, 2e. McGraw Hill.
- ^ S2CID 21920197.
- ^ "Pudendal Block". April 26, 2012.
- ^ a b c Yeung, B; Mueller, J (2016). "Peripheral Nerve Blocks: Trunk and Perineum". Anesthesiology Core Review: Part Two Advanced Exam. McGraw Hill.
- ^ S2CID 231543367.
- ^ a b c Smith, A; LaFlamme, E; Komanecky, C (2021). "Pain Management in Labor". American Family Physician. pp. 355–364.
- ^ S2CID 51888261.
- ^ S2CID 237150017.
- S2CID 231936104.
- ^ S2CID 220387990.
