Spinal Anesthesia

Spinal Anesthesia – Technique

Spinal anesthesia also called spinal block, subarachnoidal block or intradural block, is a form of regional anesthesia with the injection of a local anesthetic into the subarachnoid space. The injection is performed through a thin spinal needle, usually 9 cm (3.5 inch) long. The puncture with the spinal needle is done either with or without an introducer. The introducer is a short large-bore needle that the thin spinal needle is inserted through. The spinal needle either has a sharp needle tip, which usually does not need any introducer or a blunt needle that needs the introducer. Spinal anesthesia is used for anesthesia and surgical procedures of the lower part of the body  and in some pain indications. Level of puncture is usually between L2 and L3 or L3 and L4.


  • Surgical procedures of lower body below the umbilicus, for example peripheral vascular surgery or low abdominal surgery
  • Obstetric & gynecological procedures
  • Urology, such as TURP or TURB
  • Orthopedic operations of lower limb
  • Pain relief via catheter in severe chronic pain, such as ischemic pain
  • Late childbirth analgesia


The patient is placed prior to the blockade in the sitting or lying position. In urological surgery and sectio it is usually considerably easier to administer spinal with the patient in sitting than lying. In orthopedic surgery, spinal is usually placed with the patient lying on the side. The back is washed and sterilized. The puncture and deposition of the spinal is done under sterile conditions. In the lying side position it is very important with maximum flexion in the lumbar part with the patient far out on the edge of the table, usually an assistant may adjust the position.

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  • Relaterad bild
  • Bilderesultat for spinalanestesi
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Puncture technique

Usually median technique – 70-90 degree angle to the skin with the needle, with 20-40 degree angulation in the cranial direction.

Spinal needles

Sharp (Cutting) needles

  • Spinocan Spinal
  • Quincke
  • Pitkin

Non-cutting bevel with a distal side hole – “Pencil Point Spinal needles

  • Whitacre
  • Sprotte
  • Gertie Marx

Needle size: 25-26-27 G (gauge). Pencil Point Spinal needles uses an introducer while sharp needles do not.

  • Bildresultat för spinal anesthesia needles

Lateral technique: 1-3 cm from the median line at a 70-90 degree angle to the skin with 30-50 degree angulation in the cranial direction of the needle.


  • Dissiminated intravascular coagulopathy
  • Any significant coagulopathy
  • Skin infection on the injection site
  • Earlier epidural or spinal hematoma or other complication
  • Neurological abnormal symptoms of peripheral origin

Relative contraindications

  • Neurological malfunction (MS, myasthenia gravis – though controversial if contraindication really exists)
  • Patient opposition (does clearly not want any spinal anesthesia)
  • Spinal cord, spinal stenosis or fresh trauma in the back
  • Sepsis
  • Patients with consciousness
  • Tattoo on the lumbar region

Coagulation tests

  • Spinal produces less puncture complications than epidural.
  • APT(T) should be normal
  • PK/INR > 1.4 and TPC> 100, on comfort gain
  • PK/INR> 1.6 or TPC 50-100, on morbidity gains
  • PK/INR> 1.8, TPC 30-50, doubtful with spinal, about mortality gain
  • At PK/INR > 1.4 or TPC <100, adjust coagulation before puncture

Level of puncture (injection level)

  • Orthopedic surgery of lower extremity, between L2-L3, L3-L4, L4-L5.
  • Caesarian Sectio: L2-L3, L3-L4
  • Peripheral vascular surgery: L2-L3, L3-L4.


  • Iliac Crest – L4

Sensory evaluation – propagation 

  • Th 4 – mamill
  • Th 8 – rib cage
  • Th 10 – umbilical level
  • Th 12 – groin

Bromage Scale derm2large.gif

  • 0 = Can lift the leg with stretched knees
  • 1 = Can bend in knee joint
  • 2 = Can bend in ankle
  • 3 = Can not bend in the ankle, paralysis


  • VAS-Scale
  • Blood pressure and pulse, leg mobility every 4 hours
  • Saturation rate and respiratory rate 1 times/h first 6 (fentanyl, sufenta) and 12 hours (morphine) at startup. At dose change/bolus 2 and 4 h respectively.
  • Then check every four hours.

Removal of spinal catheter

  • Patients do not usually need any special sedation
  • Wash the puncture site with alcohol
  • Remove the catheter gently
  • Check the catheter tip after removal
  • Keep urinary catheter for 6 hours
  • Keep venous access 6 hours
  • Continue checking for 4 hours
  • Wait at least 2 hours before new anticoagulation therapy is given

Spinal Anesthesia and anticoagulation

  • LMWH> 5000E/40 mg – at least 24 hours prior to spinal anesthesia
  • LMWH 2500-5000 E – be given no later than 12 h before puncture/manipulation
  • Heparin i v – wait 3 h + new APT(T)
  • Single therapy low dose salicylates and or NSAIDs – at comfort gain
  • High dose salicylates – in case of morbidity gain
  • Salicylates/Clopidogrel (Plavix) – at mortality gains
  • Clopidogrel (Plavix) should be discontinued for 5 days


Spinal Anaesthesia – Drugs

Lower limb surgery including hip surgery

Local Anaesthetic AgentConcentrationDose (ml)Dose (mg)Onset TimeDuration
Bupivacaine 5 mg/ml2–4 ml 10–20 mg5–15 min2–4 hours
Bupivacaine with glucose 5 mg/ml2–4 ml10–20 mg3–15 min1,5–3 hours
Ropivacaine 5 mg/ml3–4 ml15–20 mg1–5 min 2–6 hours
Levobupivacaine 5 mg/ml 3 ml15 mg
Urologic surgery
Bupivacaine 5 mg/ml 1,5–3 ml7,5–15 mg5–8 min1,5–3 hours
Abdominal Surgery
Bupivacaine 5 mg/ml2–4 ml10–20 mg5–8 min45–60 min
Lower limb surgery including hip surgery

Spinal Anaesthesia for Caesarian Sectio (C-Sec)

Local Anaesthetic AgentConcentrationDose (ml)Opioid
Bupivacaine with glucose5 mg/ml1,8–2,4 ml (7,5–12,5 mg)
Bupivacaine with glucose 5 mg/ml1,8-2,4 ml + Fentanyl 15-25 μg
Bupivacaine with glucose 5 mg/ml1,8-2,4 ml + Morphine 0,1 mg (0.4 mg/ml 0.25 ml)
Bupivacaine with glucose 5 mg/ml1,8-2,4 ml + Fentanyl 15-25 μgram + Morphine 0,1 mg (0,4 mg/ml 0,25 ml)
Ropivacaine 5 mg/ml1,5-3 ml (7,5-15 mg)

Spinal Anesthesia for pain during delivery final

Local Anaesthetic AgentBrand name
Local Anaesthetic Agent
ConcentrationDose (ml)Opioid
Ropivacaine Naropin®5 mg/ml0,2-0,3 ml (1-1,25 mg)Sufentanil 5 μg/ml 1-1,5 ml (7,5 mikrog)
Bupivacaine Marcaine Spinal®5 mg/ml0,2-0,4 ml (1-2 mg)Sufentanil 5 μg/ml 1-1,5 ml (7,5 mikrog)

Opiates as Adjuncts in Spinal Anesthesia

Local Anaesthetic AgentConcentrationDose in mgDose in ml
Morphine0.4 mg/ml0,1–0,2 mg0,25-0,5 ml
Fentanyl50 mikorg/ml20–40 μg0,4-0,8 ml
Sufentanil5 μg/ml5–10–(15) μg1-1,5 ml

Bupivacaine (Marcaine) Spinal 5 mg/ml

  • Lower limb procedures including hip surgery.
  • Dose: 2-4 ml, 10-20 mg.
  • Onset time 5-8 min.
  • Duration 1.5-4 hours.
  • The recommended injection site is below L3.

Bupivacaine (Marcaine) Spinal Heavy 5 mg/ml

  • Lower limb infections including hip surgery.
  • Dose: 2-4 ml, 10-20 mg. Onset time 5-8 min. Duration 1.5-4 hours.
  • Urological Surgery: Bupivacaine (Marcaine) Spinal Heavy.
  • Dose: 1.5-3 ml, 7.5-15 mg. Onset time 5-8 min. Duration 2-3 hours. The recommended injection site is below L3.
  • Surgery: Bupivacaine (Marcaine) Spinal Heavy. Dose: 2-4 ml, 10-20 mg. Onset time 5-8 min. Duration 45-60 min.

Ropivacaine (Naropin)  5 mg/ml

  • Lower limb infections including hip surgery.
  • Dose: 3-4 ml, 15-20 mg.
  • Onset time 1-5 min.
  • Duration 2-6 hours.

Levobupivacaine (Chirocaine)  5 mg/ml

  • Lower limb infections including hip surgery.
  • Dose: 3 ml, 15 mg.

Intrathecal Pain Management

Intrathecal pain treatment is applied by placing an epidural catheter under strict sterile conditions in the spinal space via a lumbar puncture with an epidural needle. The catheter is then used for continuous spinal anesthesia via pump – e g Gemstar pump or CAD pump. This puncture is performed as a spinal anesthesia with an epidural needle. Through the epidural needle, the spinal space is first identified with a spinal needle, a “needle-through-needle technique”. Next, an epidural catheter is placed high up about 15 cm above insertion into L2-L3. The catheter may be advantageously tunnelled subcutaneously from the site of insertion to the side of the patient’s truncus. Intrathecal drug is 100-300 times stronger than perorally given.



High intracranial pressure, sepsis, severe coagulation disorder, increased bleeding risk, anticoagulation treatment (Waran®, Plavix®) and infected skin, e g in the event of skin ulcers near the insertion site.

Preoperative blood samples

PK (INR), APTT, platelets, CRP.

Anticoagulation-treated patients

Waran® treatment is dismissed. Operating doctors should report acceptable INR in each case. Patients treated with low molecular weight heparin, eg Fragmin®, should be treated as follows: At Fragmin 5000 E s c, 10 hours should pass before insertion, position adjustment or removal. Subsequent Fragmin® dose is given 2 hours after insertion or removal of the intrathecal catheter. At Klexane® 40 mg s.c. 10 hours should pass before loading, positioning or deletion. Following Klexane dose is given 2 hours after insertion, position adjustment or removal of the intrathecal catheter. Plavix® is ​​exposed 10 days before surgery.

Medicines for intrathecal administration:

  • 95 ml of Bupivacaine (Marcain®) 5 mg/ml are mixed with 5 ml of Morphine 10 mg/ml to a volume of 100 ml.

The concentration of Bupivacaine (Marcain®) is 4.75 mg/ml and the concentration of morphine becomes 0.5 mg/ml. A recommended starting dose is 0.3 ml/h with the ability to provide a bolus dose of 0.2 ml if necessary. Peroperative pain relief usually occurs by the administration of local anesthetic agents with the addition of opiates, usually morphine 0.1 mg, 100 μg. There is a possibility of adding a mixture of opiates and clonidine (Catapresan). Such a mixture is, for example:

  • Morphine Special 0.1-0.3 mg, 0.4 mg/ml, 0.25-0.75 ml
  • Sufentanil (Sufenta®) 10 μg, 5 μg/ml, 2 ml
  • Clonidine (Catapresan®) 75 μg, 150 μg/ml, 0.5 ml

Safety checks with intrathecal (subarachnoidal) infusion of opiods

After the morphine has been given intratheously, the following controls are performed for 12 hours and after intrathecal fentanyl or sufentanil have been given for 6 hours. 1 time / hour after spinal anesthetic has been given and checked:

  • VAS
  • Sedation Degree
  • Respiratory Rate (if the degree of sedation > 1)
  • Nausea
  • Itching

Hereafter, checks are performed every 4 hours for another 12 hours. Extra control 2 times/hour for 2 hours when adding sedative or respiratory depression medication. CAD for at least 12 hours. Check bladder function after CAD has been removed.

Dosing for Spinal Anaesthesia

By Mattias Gunther, VO Anesthesia and Intensive Care, Södersjukhuset, Stockholm

Updated 2020-10-30

Spinal doses of anesthetics

Dosages are set as baseline values. Each patient must be assessed individually. Doses are given in milliliters (ml) for each drug.
OperationBupivacaine Spinal with glucose ("heavy")
5 mg/ml
Bupivacaine Spinal
5 mg/ml
0,05 mg/ml
Morphine Special
0,4 mg/ml
Other drugs
Caesarian Sectio 2,0-2,4 ml 0,1 ml 0,25 ml *
Childbirth injuries suturing1
Sphincter rupture1,0-1,6 ml ev. 0,2 ml
Placental dissolution1,2 ml 0,2 ml
Childbirth spinal (if parturition is expected < 3 h)0,5 ml (alt. 1 ml Bupivacaine 2,5 mg/ml) Sufentanil 1 ml 5 µg/ml
Prolaps uteri1,8-2,5 ml 0,2 ml
Epidural refill for sectio/sphincter rupture (epidural!) 1 ml (epidural) Ropivacaine 10-20 ml 7,5 mg/ml
Vaginal hysterectomy (without GA)2,6-2,8 ml 0,2 ml 0,25 ml
Abdominell hysterektomi (med GA) 2,0-2,5 ml 0,2 ml 0,25 ml
Hip fracture1,6-2,2 ml 0,2-0,4 ml
Hip joint surgery (possibly CSE)1,6-2,2 ml 0,2-0,4 ml clonidine 0,4 ml 150 µg/ml if not CSE
Knee plastic unilateral2,6-3,0 ml1,6-3,0 ml
Knee replacement surgery total / revision (possibly CSE)1,6-2,4 ml 0,2-0,4 ml clonidine 0,4 ml 150 µg/ml if not CSE
Operation of lower leg, ankle, or foot1,8-2,4 ml1,8-2,4 mlev. 0,2-0,4 ml alternativt Bupivacaine Spinal
Amputation leg (CSE preferred)1,6-2,2 ml 0,4 ml ev 0,25 ml if not CSE
Arthroscopy knee1,8-2,4 ml 1,8-2,4 ml
TUR-P, TURIS-P 1,8-2,5 ml
TUR-B, Cysto-PX, TUIP, internal urethrotomy1,8-2,5 ml
TUR-B low dose on day care surgery (1 h block)1 ml Sufentanil 1 ml 5 µg/ml
Urethroscopy/Lithotripsy2,5-3,0 ml ev. 0,2 ml
General surgery
Laparoscopic / robot colon surgery
Rectum amputation
1 ml0,5 ml
Inguinal hernia/vascular surgery (operation time < 3 h)2,8 ml
Peripheral vascular bypass3,0-3,2 mlev. 0,2 ml
Inguinal hernia2,6-3 ml
* not on-call time if the post operation unit cannot monitor for 12 hours

Postoperative post spinal anesthesia monitoring

  Respiratory monitoringMonitoring of motor skills according to BromageBromage-scale
Bupivacaine-8 hours0 = can lift the leg with the knee stretched
Fentanyl 6 hours-1 = can bend at the knee joint
Morphine 12 hours-2 = can bend at the ankle
Clonidine- 10 hours3 = can not bend the ankle, paralysis