Spinal Anesthesia: A Step-by-Step Procedure Guide

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ARTICLE DATA

Author: Usman Shah Reviewer : Burhan Ahmed, MBBS

Specialty Editor: Col. Mansoor-Ul-Haq FCPS Anesthesiology

Spinal anesthesia refers to the technique whereby local anesthetics are administered in the cerebro-spinal fluid in the sub-arachnoid space to achieve regional anaesthesia in cases where general anaesthesia is not required or recommended. It results in anesthesia in the umbilical region targeted according to the nerve supply.

Indications:

  1. Hernia repairs
  2. Gynaecological surgeries (manual removal of a retained placenta)
  3. Urological repairs
  4. Operations in the genital region
  5. Operations in perineum

Contra-indications:

  1. Inadequate resuscitation measures
  2. Hypovolemia
  3. Clotting and Bleeding disorders
  4. Sepsis and septicaemia
  5. Neurological diseases
  6. Unwilling Patient
  7. Non suitable Operating Room environment where the team is not accustomed to operating with patient wide awake.

Risks Involved:

Spinal and epidural anesthesia are generally safe. Ask your doctor about these possible complications:

  • Allergic reaction to the anesthesia used
  • Bleeding around the spinal column (hematoma)
  • Retention of urine
  • Hypotension
  • Infection in your spine (meningitis or abscess)
  • Nerve damage
  • Seizures (As a side affect to anesthetic overdose or reaction)
  • Severe headache (PDPH Post Dural Puncture Headache)

Pre-procedure preparation:

  • Councelling: The patient must be informed of the type and admisitration of anesthesia along with the more common sensations associated with the procedure including alteration in sense and weakness of legs. They must be assured, however, that no pain will be felt once it is administered.
  • Pre-loading: Depending on the type of procedures and age and associated co-morbidities of the patient, 500-1500 of IV fluid may need to be administered before the procedure. The preffered fluids include crytalloids namely normal ( 0.9%) saline and Hartmans.
  • Before you start place all the monitors and ensure you have a wide bore functioning I/V line. Record the baseline vitals.  <

Performance of the procedure:

It is most easily performed when there is maximum flexion of the lumbar spine. This can best be achieved by sitting the patient on the operating table and placing their feet on a stool. If they then rest their forearms on their thighs, they can maintain a stable and comfortable position. Alternatively, the procedure can be performed with the patient lying on their side with their hips and knees maximally flexed.

  1. Scrub and glove up carefully.
  2. Check the equipment on the sterile trolley.
  3. Draw up the local anesthetic to be injected intra-thecally into the 5ml syringe, from the ampoule opened by your assistant. Read the label. Draw up the exact amount you intend to use, ensuring that your needle does not touch the outside of the ampoule (which is unsterile).
  4. Draw up the local anesthetic to be used for skin infiltration into the 2ml syringe. Read the label carefully.
  5. Clean the patient’s back with the swabs and antiseptic ensuring that your gloves do not touch unsterile skin. Swab radially outwards from the proposed injection site. Discard the swab and repeat several times making sure that a sufficiently large area is cleaned. Allow the solution to dry on the skin.
  6. Drape the patients back with a sterile towel to gain more freedom of movements of your hands in handling the back of your patient.
  7. Locate a suitable inter-spinous space. You may have to press fairly hard to feel the spinous processes in an obese patient.
  8. Inject a small volume of local anaesthetic under the skin with a disposable 25-gauge needle at the proposed puncture site.
  9. Insert the introducer if using a 24-25 gauge needle. It should be advanced into the Ligamentum Flavum.
  10. If an Epidural is intended care should be exercised in thin patients that an inadvertent dural puncture does not occur and then we are using a 18 G Epidural needle.
  11. Insert the spinal needle (through the introducer, if applicable). Ensure that the stylet is in place so that the tip of the needle does not become blunt. It is imperative that the needle is inserted and stays in the midline and that the bevel is directed laterally. It is angled slightly cephalad (towards the head) and advanced slowly. An increased resistance will be felt as the needle enters the ligamentum flavum, followed by a loss of resistance as the epidural space is entered. Another loss of resistance may be felt as the dura is pierced and CSF should flow from the needle when the stylet is removed. If bone is touched, the needle should be withdrawn a centimetre or so and then re-advanced in a slightly more cephalad direction again ensuring that it stays in the midline. If a 25 gauge spinal needle is being used, be prepared to wait 4 to 5 seconds for CSF to appear after the stylet has been withdrawn. If no CSF appears, replace the stylet and advance the needle a little further and try again.
  12. When CSF appears, take care not to alter the position of the spinal needle as the syringe of local anaesthetic is being attached. The needle is best immobilized by resting the back of the non-dominant hand firmly against the patient and by using the thumb and index finger to hold the hub of the needle. Be sure to attach the syringe firmly to the hub of the needle; hyperbaric solutions are viscous and resistance to injection will be high, especially through fine gauge needles. It is, therefore, easy to spill some of the local anaesthetic unless care is taken. Aspirate gently to check the needle tip is still intrathecal and then slowly inject the local anaesthetic. When the injection is complete, withdraw the spinal needle, introducer and syringe as one and apply a sticking plaster to the puncture site.

Assessment of the block:

  • Ask the patient to lift legs.
  • Ask for sensation of pain after pin prick.
  • Feel for cold sensations after administration of aerosol spray or cold swab.

References:

  • Casey W. Spinal Anaesthesia – a Practical Guide. Update in anaesthesia, 2000; 8; 1- 7 .
  • Collins C, Gurug A. Anaesthesia for Caesarean section. Update in Anaesthesia 1998;9:7-17
  • Torr GJ, James MFM. The role of the anaesthetist in pre-eclampsia. Update in Anaesthesia 1998;9:17-22
  • Morgan P. Spinal anaesthesia in obstetrics (a review). Canadian Journal of Anaesthesia. 1995;42:1145-63
  • Ngan Kee WD. Intrathecal pethidine: pharmacology and clinical applications. Anaesthesia and Intensive Care 1998;26:137-146.
  • Ramasamy D, Eadie R. Transient radicular irritiation after spinal anaesthesia with 2% lignocaine. British Journal of Anaesthesia 1996, 79, 394-395
  • Rawal N, Van Zudert A, Holmstrom B, Crowhurst JA. Combined spinal epidural techniques. Regional Anaesthesia. 1997;5:406-423.
  • Williams D. Subarachnoid saddle block using pethidine. Update in Anaesthesia 1998;9:47-8

  • asradew

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  • RNA IBRAHIM

    Precise and rich in imformation.i love it.hope to get more.

  • That’s a crcakerjack answer to an interesting question

  • patric ogalo

    Thanks for the information

  • Derek Rabor

    A very concise and easy step by step description of the proceedure. Very easy to follow.