Procedures: Lumbar Puncture

Indications :

• To obtains cerebrospinal fluid for analysis, and/or
• To decrease the volume in the subarachnoid space (decreasing intracranial pressure)

Contraindications :

• Increased intracranial pressure - risk of consequent transtentorial or tonsillar herniation
• Bleeding diathesis
• Cardiorespiratory compromise
• Infection at site of needle insertion

Instruments :

• Manometer
• Spinal Needle (22G, stilette in place)

Procedure :

• Place the patient in the left lateral position. (Back should be kept as close as possible to the edge of the bed and knees fully flexed till chin)
• Mark L3/4 intervertebral space (usually lies in the transverse plane of the iliac crests) by a gentle indentation of thumb nail on the overlying skin.
• Wash hands, put on surgical mask and sterile gloves.
• Sterilize the back with povidone iodine.
• Inject local anesthesia (lidocaine 1% 0.25-0.5mL) under skin at marked site.
• Wait for 1 minute, then insert spinal needle through the marked site. You will feel a 'give' as the spinal needle enters into the subarachnoid space.
• Withdraw the stilette. Wait for CSF to flow out.
• Measure the CSF opening pressure with a manometer. (normal= 60-150mm of CSF)
• Collect CSF fluid in in three sterilized stoppered test tubes.

Post-procedure Care :

• The patient should lie flat for 8-24 hours after the procedure, in order to reduce the chance of post-lumbar puncture headache developing.
• Check CNS observation and BP regularly.

Complications :

• Spinal headache
• Epidural hematoma
• Meningitis
• Nerve Root injury
• Epidermoid formation

CSF Findings :

A) Bacterial Meningitis

• Physical characteristics: Yellowish and turbid
• Cytology (cells/microL) : Lymphocytes: 5-50; Polymorphs: 200-2000
• Proteins (g/L) : 0.5 - 2.0
• Glucose (mmol/L) : <2.0
• Stained deposit : Bacteria
• Culture : Positive

B) Tuberculous Meningitis

• Physical characteristics: Colourless, sometimes viscous or yellow
• Cytology (cells/microL) : Lymphocytes: 100-300; Polymorphs: 0-100
• Proteins (g/L) : 5.0-15
• Glucose (mmol/L) : <2.0
• Stained deposit : Tubercle bacilli in CSF in most cases
• Culture : Positive

LUMBAR PUNCTURE.

Indications:
Absolute:

• Meningitis
• Encephalitis
• Subarachnoid hemorrhage
• Guillian Barre Syndrome
• Acute demylinating disease
• Unexplained coma
• Unexplained dementia

Therapeutic:

• Methotrexate in leukemia
• Spinal anaesthesia
• Benign intracranial hypertension

Relative:

• Multiple sclerosis
• Pyrexia of unknown origin
• Neurosyiphilis

Contraindications:

• Raised intracranial pressure
• Spinal deformity
• Local infections
• Coagulation disorders

Materials
1-Material for sterile technique(only gloves and mask are necessary)
2-Spinal Needle, 20 and 22-gauge
3-Manometer
4- Three-way stopcock
5-Sterile drapes
6-1% lidocaine without epinephrine in a 5-cc syringe with a 22 and 25-gauge needles
7-Material for skin sterilization (povidone iodine)
8- Adhesive dressing
9- Sponges


Procedures:

• first the patient is usually placed in a left (or right) lateral position with his/her neck bent in full flexion and knees bent in full flexion up to the chest.

• Back will be cleansed with an antiseptic solution and draped with sterile towels. The physician will wear sterile gloves during the procedure.
• Once the appropriate location is palpated, local anaesthetic is infiltrated under the skin and then injected along the intended path of the spinal needle.

• A spinal needle is inserted, usually between the lumbar vertebrae L3/L4 or L4/L5 and pushed in until there is a "give" that indicates the needle is past the dura mater.

• The stylet from the spinal needle is then withdrawn and drops of cerebrospinal fluid are collected. The opening pressure of the cerebrospinal fluid may be taken during this collection by using a simple column manometer.

• The procedure is ended by withdrawing the needle while placing pressure on the puncture site.

• Adhesive bandage will be placed over the injection site. The test tubes will be taken to the laboratory for analysis.

CSF Analysis:


1)bacteria

Opening pressure raised
Appearance turbid
Total WBC raised
Cells neutrophils predominate
Protein >45mg/dl
Sugar low

2)tubercular

opening pressure raised
apperance cob web
Total WBC raised
cells lymphocyte predominate
protein >100-800mg/dl
sugar low



Post Procedure care:

• lie flat for up to eight hours to reduce incidence of headache.

• drink additional fluids to rehydrate after the procedure. This replaces the CSF that was withdrawn during the spinal tap and reduces the chance of developing a headache.

• limit activity for 24 hours following the procedure.

Complications:


Postdural puncture headache

Cranial neuropathies

Nerve root irritation, herniation, and transaction

Low back pain

Implantation of epidermal tumors

Infections

Bleeding complications
Intracranial bleeding
Traumatic lumbar puncture
Spinal hematomas

Indications
1. Find a cause for symptoms possibly caused by an infection,inflammation,cancer or bleeding in the area around the brain or spinal cord.
2. Diagnose certain diseases of the brain and spinal cord such as multiple sclerosis or Guillain-Barre syndrome.
3. Measure the pressure of cerebospinal fluid in the space surrounding the spinal cord.If the pressure is high,it may be causing certain symptoms.
4. Put anesthetics or medicines into the CSF.Medicines may be injected to treat leukemia and othe types of cancer of the central nervous system.
5. Put a dye in the CSF that makes the spinal cord and fluid clearer on x-ray pictures(myelogram).This may be done to see whether a disc or a cancer is bulging into the spinal canal.
6. May be used to lower the pressure in the brain caused by too much CSF in some conditions.

Contraindications

1. Absolute contraindications :
* Midline shift
* Loss of suprachiasmatic and basillar cisterns
* Posterior fossa mass
* Loss of the superior cerebellar and quadrigeminal plate cisterns
* Infected skin over the needle entry side
2. Relative contraindications
* Increased intracranial pressure
* Coagulapathy
* Brain abcess
Intruments
1. Material for sterile technique (gloves and mask)
2. Spinal needle 20 and 22 gauge
3. Manometer
4. Three way stopcock
5. Sterile drapes
6. 1% lidocaine without epinephrine in a 5cc syringe with a 22 and 25 gauge needles
7. Material for skin sterilizations
8. Adhesive dressing
9. Sponges - 10 x 10

Procedure
1. Place the patient in lateral decubitus position lying on the edge of the bed facing away from you.Place the patient in a knee chest position with the neck flexed.
2. Find the L4 spinous process and prepare the skin.Put on sterile gloves and drape the patient.
3. Anesthetize the skin using 1% lidocaine in the 5ml syringe with the 25 gauge needle.Insert in the midline with the needle parallel to the floor and the point directed towards the patients umbilicus.
4. Advanci in slowly about 2cm or untill a `pop` is heared.Then withdraw the stylet in every 2 to 3 mm advance to the skin and redirect the needle.
5. Whwn CSF begins to flow,discard the few drops.
6. Measure the opening pressure.
7. Remove the manometer and allow 1 to 2 cc of CSF to flow into each sterile tubes.
8. Withdraw the needle without replacing the stylet
9. Dress the puncture site with a bandage.Have the patient lie in bed for a few hours.

Complications
1. Post spinal headache
2. Bloody tap
3. Dry tap
4. Infections
5. Hemorrhage
6. Dysesthesias
7. Postdural puncture and cerebral herniation

CSF (bacterial)
*Polymorphs
*Cell count: 1000-5000 per mm3
*Low glucose
*Normal or elevated protein
*Gram stain positive

CSF (TB)
*Polymorphs or lympocytes or mixed
*cell count: 50-5000 permm3
*Low glucose
*Elevated protein
*Gram stain negative

Lumbar Puncture
Indications:

• Suspected CNS infection
• Suspected subarachnoid hemorrhage
• Therapeutic reduction of cerebrospinal fluid (CSF) pressure
• Sampling of CSF for any other reason

Contraindications:

• Local skin infections over proposed puncture site (absolute contraindication)
• Raised intracranial pressure (ICP); exception is pseudotumor cerebri
• Suspected spinal cord mass or intracranial mass lesion (based on lateralizing neurological findings or papilledema)
• Uncontrolled bleeding diathesis
• Spinal column deformities (may require fluoroscopic assistance)
• Lack of patient cooperation

Instruments:

• Gloves and Mask
• Spinal Needle, 20 and 22-gauge
• Manometer
• Sterile drape
• 1% lidocaine in a 5-cc syringe with a 22 and 25-gauge needles
• Povidone iodine solution
• Adhesive dressing
• Sponges

Procedure:

• Obtain consent from patient after a detailed explanation of the procedure and its complications to the patient
• Place the patient in the lateral decubitus position lying on the edge of the bed and facing away from operator. Place the patient in a knee-chest position with the neck flexed. The patient's head should rest on a pillow, so that the entire cranio-spinal axis is parallel to the bed. Sitting position is the second choice because there may be a greater risk of herniation and CSF pressure cannot be measured
• Find the posterior iliac crest and palpate the L4 spinous process, and mark the spot gently with a fingernail. Clean the skin by starting at the puncture site and working outward in concentric circles. Put on sterile gloves. Drape the patient
• Anesthetize the skin using the 1% lidocaine in the 5 mL syringe with the 25-gauge needle. Change to 22-gauge needle before anesthetizing between the spinous process. Insert in the midline with the needle parallel to the floor and the point directed toward the patient's umbilicus
• Advance slowly about 2 cm or until a "pop'' (piercing a membrane of the dura) is heard. Then withdraw the stylet in every 2- to 3-mm advance of the needle to check for CSF return. If the needle meets the bone or if blood returns (hitting the venous plexus anterior to the spinal canal), withdraw to the skin and redirect the needle. If CSF return cannot be obtained, try one disk space down
• When cerebrospinal fluid begins to flow from the needle, discard the first few drops.
• Measure the opening pressure with a manometer
• Remove the manometer and allow 1 to 2 cc of CSF to flow into each of the three sterile tubes. Send the first for glucose and protein, the second for Gram stain and culture and sensitivity (C&S), and the third for cell count and differential. A fourth tube, when indicated, is collected for viral titer or cultures, India ink preparation, Cryptococcus antigen, VDRL, or cytology
• Withdraw the needle without replacing the stylet
• Dress the puncture site with a bandage.

Post Procedure Care:

• Cover the puncture site with a band-aid or occlusive dressing (eg Tegaderm)
• Bed rest to reduce incidence of headache following the procedure

Complications:

• Spinal headache
• Brain herniation
• Spinal root injury
• Infections
• Hematomas
• Epidermoid

CSF findings:

Bacterial meningitis:

• Turbid appearance
• Total WBC raised
• Cells predominatly neutrophils
• Protein >45mg/dl
• Glucose low

Tubercular meningitis:

• Cob web appearance
• Total WBC raised
• Cells predominatly lymphocytes
• Protein >100-800mg/dl
• Glucose low

Lumbar Puncture

Indication :
The most common reason is to remove a small amount of CSF for examination and diagnosis of various disorders. CSF is tested for red and white blood cells, protein, glucose (sugar), clarity, color, and the presence of bacteria, viruses, or abnormal cells. Excess CSF may also be removed in patients who have an overproduction or decreased absorption of the fluid.

• meningitis - an inflammation of the membrane covering the brain and spinal cord. The inflammation is usually the result of a viral, bacterial, or fungal infection, or the result of exposure to toxins or abnormal cells.
• encephalitis - an inflammation of the brain that is usually caused by a virus.
• certain cancers involving the brain and spinal cord
• bleeding in the subarachnoid space
• Reye syndrome - a potentially fatal disease that causes severe problems with the brain and other organs. Although the exact cause of the disease is not known, there has been an association between giving aspirin to children and the development of Reye syndrome. It is now advised not to give aspirin to children during illnesses, unless prescribed by your child's physician.
• myelitis - an inflammation of the spinal cord or bone marrow.
• neurosyphilis - a stage of syphilis during which the bacteria invades the central nervous system.
• Guillain-Barré syndrome - a disorder in which the body's immune system attacks part of the nervous system.
• demyelinating diseases - diseases that attack the protective coating that surrounds certain nerve fibers (e.g., multiple sclerosis or acute demyelination polyneuropathy).

In addition, a lumbar puncture may be used to measure the pressure of the CSF, which flows freely between the spinal column and the brainFinally, a lumbar puncture may be performed therapeutically to inject medications directly into the spinal cord.

Complication:

• A small amount of CSF can leak from the needle insertion site. This can cause headaches after the procedure.

• There is a to the legs or lower back pain may be experienced.
• There is a risk of bleeding in the spinal canal.
• Should there be increased slight risk of infection because the needle breaks the skin’s surface, providing a possible portal of entry for bacteria.
• A temporary numbness pressure or swelling in the brain before the procedure, a lumbar puncture can cause fluctuations in the CSF fluid levels, resulting in brain herniation. Herniation is a dangerous event in which the brain stem or top of the spinal column is compressed by swelling of the brain.

Before the procedure:

• explain the procedure to patient
• take consent from patient
• Generally, fasting is not required prior to a lumbar puncture unless a sedative is prescribed.
• Notify if patient is pregnant or suspect you may be pregnant.
• Notify if patient have a history of seizures or if you are taking any prescribed medications for seizures.
• Notify if patienthave a history of bleeding disorders or any anticoagulant (blood-thinning) medications, aspirin, or other medications that affect blood clotting. It may be necessary stop these medications prior to the procedure.

During the procedure:

• remove any clothing, jewelry, or other objects that may interfere with the procedure.
• You will be given a gown to wear.
• empty the bladder prior to the start of the procedure.
• During the lumbar puncture lie on the examination table on your side with your chin tucked to your chest and knees tucked to your abdomen. Alternatively, you may sit on the edge of an examination table with your arms draped over a table positioned in front of you. In either position the back is arched, which helps to widen the intervertebral spaces.
• A lumbar puncture is a sterile procedure. Therefore, patient back will be cleansed with an antiseptic solution and draped with sterile towels. The physician will wear sterile gloves during the procedure.
• anesthetize the skin by injecting a local anesthetic that numbs the site. This injection may sting for a few seconds, but makes the lumbar puncture less painful.
• The hollow needle will be inserted through the numbed skin and into the subarachnoid space where the CSF is located. patient will feel some pressure while the needle is inserted. patient must remain absolutely still during the insertion of the needle.
• The CSF will begin to drip out of the needle and a small amount, about one tablespoon, will be collected into test tubes.
• If the physician needs to inject medication into the spinal canal, it will be given through the same needle after the CSF is collected.
• When the procedure is completed, the needle will be removed and an adhesive bandage will be placed over the injection site. The test tubes will be taken to the laboratory for analysis.
• patient should notify the physician if you feel any numbness, tingling, headache, or lightheadedness during the procedure.

patient may experience discomfort during a lumbar puncture. The physician will use all possible comfort measures and complete the procedure as quickly as possible to minimize any discomfort or pain.

After the procedure:
patient will be asked to lie flat for up to eight hours after the lumbar puncture is completed. This helps reduce the incidence of a headache. patient will be allowed to roll from side to side as long as your head is not elevated. patient may be asked to urinate in a bedpan during the time that you are required to stay flat.
Patient will be asked to drink additional fluids to rehydrate after the procedure. This replaces the CSF that was withdrawn during the spinal tap and reduces the chance of developing a headache.
When patient have completed the recovery period, you may be taken to your hospital room (if the procedure was performed elsewhere in the hospital) or discharged to your home.
Once you are at home, notify physician of any abnormalities, such as numbness and tingling of the legs, drainage of blood or pain at the injection site, inability to urinate, or headaches. If the headaches persist for more than a few hours after the procedure, or when you change positions, you should contact your physician.
Patient is instructed to limit their activity for 24 hours following the procedure. Generally, if no complications occur, patient may return to yheir normal diet and activities.

CSF Findings;

Bacteria

Tuberculosis

Opening Pressure

Elevated++

Elevated+

WBC

Increased

Increased

Differential

Neutrophil

Lymphocyte

Protein

Raised

Slightly raised

Glucose

Very low

Normal

Specific

Gram stain culture

Serology

Culture

Lumbar Puncture

Indication :
The most common reason is to remove a small amount of CSF for examination and diagnosis of various disorders. CSF is tested for red and white blood cells, protein, glucose (sugar), clarity, color, and the presence of bacteria, viruses, or abnormal cells. Excess CSF may also be removed in patients who have an overproduction or decreased absorption of the fluid.

• meningitis - an inflammation of the membrane covering the brain and spinal cord. The inflammation is usually the result of a viral, bacterial, or fungal infection, or the result of exposure to toxins or abnormal cells.
• encephalitis - an inflammation of the brain that is usually caused by a virus.
• certain cancers involving the brain and spinal cord
• bleeding in the subarachnoid space
• Reye syndrome - a potentially fatal disease that causes severe problems with the brain and other organs. Although the exact cause of the disease is not known, there has been an association between giving aspirin to children and the development of Reye syndrome. It is now advised not to give aspirin to children during illnesses, unless prescribed by your child's physician.
• myelitis - an inflammation of the spinal cord or bone marrow.
• neurosyphilis - a stage of syphilis during which the bacteria invades the central nervous system.
• Guillain-Barré syndrome - a disorder in which the body's immune system attacks part of the nervous system.
• demyelinating diseases - diseases that attack the protective coating that surrounds certain nerve fibers (e.g., multiple sclerosis or acute demyelination polyneuropathy).

In addition, a lumbar puncture may be used to measure the pressure of the CSF, which flows freely between the spinal column and the brainFinally, a lumbar puncture may be performed therapeutically to inject medications directly into the spinal cord.

Complication:

• A small amount of CSF can leak from the needle insertion site. This can cause headaches after the procedure.

• There is a to the legs or lower back pain may be experienced.
• There is a risk of bleeding in the spinal canal.
• Should there be increased slight risk of infection because the needle breaks the skin’s surface, providing a possible portal of entry for bacteria.
• A temporary numbness pressure or swelling in the brain before the procedure, a lumbar puncture can cause fluctuations in the CSF fluid levels, resulting in brain herniation. Herniation is a dangerous event in which the brain stem or top of the spinal column is compressed by swelling of the brain.

Before the procedure:

• explain the procedure to patient
• take consent from patient
• Generally, fasting is not required prior to a lumbar puncture unless a sedative is prescribed.
• Notify if patient is pregnant or suspect you may be pregnant.
• Notify if patient have a history of seizures or if you are taking any prescribed medications for seizures.
• Notify if patienthave a history of bleeding disorders or any anticoagulant (blood-thinning) medications, aspirin, or other medications that affect blood clotting. It may be necessary stop these medications prior to the procedure.

During the procedure:

• remove any clothing, jewelry, or other objects that may interfere with the procedure.
• You will be given a gown to wear.
• empty the bladder prior to the start of the procedure.
• During the lumbar puncture lie on the examination table on your side with your chin tucked to your chest and knees tucked to your abdomen. Alternatively, you may sit on the edge of an examination table with your arms draped over a table positioned in front of you. In either position the back is arched, which helps to widen the intervertebral spaces.
• A lumbar puncture is a sterile procedure. Therefore, patient back will be cleansed with an antiseptic solution and draped with sterile towels. The physician will wear sterile gloves during the procedure.
• anesthetize the skin by injecting a local anesthetic that numbs the site. This injection may sting for a few seconds, but makes the lumbar puncture less painful.
• The hollow needle will be inserted through the numbed skin and into the subarachnoid space where the CSF is located. patient will feel some pressure while the needle is inserted. patient must remain absolutely still during the insertion of the needle.
• The CSF will begin to drip out of the needle and a small amount, about one tablespoon, will be collected into test tubes.
• If the physician needs to inject medication into the spinal canal, it will be given through the same needle after the CSF is collected.
• When the procedure is completed, the needle will be removed and an adhesive bandage will be placed over the injection site. The test tubes will be taken to the laboratory for analysis.
• patient should notify the physician if you feel any numbness, tingling, headache, or lightheadedness during the procedure.

patient may experience discomfort during a lumbar puncture. The physician will use all possible comfort measures and complete the procedure as quickly as possible to minimize any discomfort or pain.

After the procedure:

patient will be asked to lie flat for up to eight hours after the lumbar puncture is completed. This helps reduce the incidence of a headache. patient will be allowed to roll from side to side as long as your head is not elevated. patient may be asked to urinate in a bedpan during the time that you are required to stay flat.

Patient will be asked to drink additional fluids to rehydrate after the procedure. This replaces the CSF that was withdrawn during the spinal tap and reduces the chance of developing a headache.

Patient is instructed to limit their activity for 24 hours following the procedure. Generally, if no complications occur, patient may return to yheir normal diet and activities.


CSF Findings;
1) bacteria

opening pressure - raised
WBC - increased
differential- neutrophil
protein- raised
glucose- very low
specific - gram stain, culture

2) tuberculosis

opening pressure- raised
WBC- increased
differential- leucocyte
protein- raised
glucose- low
specific- AFB, culture

indications :

• collest cerebrospinal fluid for suspected meningitis
• fever of unknown origin in children
• subarachnoid haemorrhage
• hydrocephalus
• benign intracranial hypertension
• to inject medicine in case of spinal anaesthesia and chemotherapy

contraindications :

• spinal deformity
• concurrent spinal infection
• local infection at the site of puncture
• any cause of raised intracranial pressure
• meningomyelocoele

instruments used :

• lumbar puncture needle
• manometer
• test tubes (3)

technique :

• patient is told to lie in the left lateral position where his chin n knees are close together as possible
• procedure is explained and consent is taken from patient.
• 3rd and 4th lunbar spines are marked.
• using sterile precautions,LIdocaine 2 % was injected in the 3rd and 4th interlumbar space.
• the special lumbar needle is pushed into the 3rd and 4th interlumbar space towards the head.
• when the needle is felt penetrated the dura mater,the stylet is withdrawn and a few drops of CSF is allowed to escape.
• CSF pressure is measured by connecting manometer to the needle.
• patient's head should be the same level as the sacrum.
• specimens of CSF is collected in 3 different sterile test tubes and sent to the laboratory.

post procedure care :

• patient's are asked to lie flat in order to prevent post lumbar puncture headache.
• analgesics are given to the patient.

complications :

• headache with nausea
• paresthesia
• weakness and loss of sensation
• paraplegia
• atrio-venous malformation
• epidural infection
• herniation

CSF findings in bacterial and tubercular meningitis :

• bacterial meningitis

cells/ml = 200 - 20 000 (mainly neutrophils)
protein mg/dl = high (>100)
glucose mg/dl = <45
causes = bacteria amebae , brain abcess

• tubercular meningitis

cells/ml = 100 - 1000 ( mainly mononuclear )
protein mg/dl = moderately high (50 - 100)
glucose mg/dl = low (<45 )
causes = tuberculosis,partly treated becterial meningitis.

indications

• meningitis - an inflammation of the membrane covering the brain and spinal cord. The inflammation is usually the result of a viral, bacterial, or fungal infection, or the result of exposure to toxins or abnormal cells.
• encephalitis - an inflammation of the brain that is usually caused by a virus.
• certain cancers involving the brain and spinal cord
• bleeding in the subarachnoid space
• Reye syndrome - a potentially fatal disease that causes severe problems with the brain and other organs. Although the exact cause of the disease is not known, there has been an association between giving aspirin to children and the development of Reye syndrome. It is now advised not to give aspirin to children during illnesses, unless prescribed by your child's physician.
• myelitis - an inflammation of the spinal cord or bone marrow.
• neurosyphilis - a stage of syphilis during which the bacteria invades the central nervous system.
• Guillain-Barré syndrome - a disorder in which the body's immune system attacks part of the nervous system.
• demyelinating diseases - diseases that attack the protective coating that surrounds certain nerve fibers (e.g., multiple sclerosis or acute demyelination polyneuropathy).

contraindications

• Absolute contraindications to lumbar puncture are as follows:
  • Unequal pressures between the supratentorial and infratentorial compartments, usually inferred by characteristic findings on the brain CT scan:
    • Midline shift
    • Loss of suprachiasmatic and basilar cisterns
    • Posterior fossa mass
    • Loss of the superior cerebellar cistern
    • Loss of the quadrigeminal plate cister
  • Infected skin over the needle entry site
• Relative contraindications to lumbar puncture are as follows:
  • Increased intracranial pressure
  • Coagulopathy
  • Brain abscess

instruments

• Gloves and Masks
• Spinal Needle, 20 and 22-gauge
• Manometer
• Sterile drape
• 1% lidocaine in a 5-cc syringe with a 22 and 25-gauge needles
• Povidone iodine solution
• Adhesive dressing
• Sponges

procedure


Position the patient in the lateral recumbent position with hips, knees, and chin flexed toward the chest in order to open the interlaminar spaces. A pillow can be used to support the head.


The sitting position may be a helpful alternative position, especially in obese patients (easier to confirm the midline). In order to open the interlaminar spaces, the patient should lean forward and be supported by a Mayo stand or another person.

Explain the procedure, benefits, risks, complications, and alternative options to the patient or the patient's representative and obtain a signed informed consent.


Wearing nonsterile gloves, locate the L3-L4 interspace by palpating the right and left posterior superior iliac crests and moving the fingers medially toward the spine. Palpate that interspace (L3-L4) as well as one above (L2-L3) and one below (L4-L5) to find the widest space. Mark the entry site with a thumbnail or a marker. To help open the interlaminar spaces, the patient can be asked to practice pushing the entry site area out toward the practitioner.

Open the spinal tray, change to sterile gloves, and prepare the equipment. Open the numbered plastic tubes and place them upright, assemble the stopcock on the manometer, and draw the lidocaine into the 10-mL syringe.

Use the skin swabs and antiseptic solution to clean the skin in a circular fashion starting at the L3-L4 interspace and moving outwards to include at least 1 interspace above and below. Just before applying the skin swabs, warn the patient that the solution is very cold, since this can be unnerving to the patient.


Place a sterile drape below the patient and a fenestrated drape on the patient. Most spinal trays contain fenestrated drapes with an adhesive tape that will keep the drape in place.

Use the 10-mL syringe to administer local anesthesia. Raise a skin wheal using the 25-ga needle and then switch to the longer 20-ga needle to anesthetize the deeper tissue. Insert the needle all the way to the hub, aspirate to confirm that the needle is not in a blood vessel, and then inject a small amount as the needle is withdrawn a few centimeters. Continue this process above, below, and to the sides very slightly (using the same puncture site). This process will anesthetize the entire immediate area so that if redirection of the spinal needle is necessary, the area will still be anesthetized. For this reason, a 10-mL syringe may be more beneficial than the usual 3-mL syringe supplied with the standard lumbar puncture kit. The 20-ga needle can also be used as a guide for the general direction of the spinal needle. In other words, the best direction in which to aim the spinal needle can be confirmed if the 20-ga needle encounters bone in one direction but not in another.
Stabilize the needle (20- or 22-ga) with the index fingers and advance it through the skin wheal using the thumbs. Orient the bevel parallel to the longitudinal dural fibers to increase the chances of the needle separating the fibers rather than cutting them (bevel facing up in the lateral recumbent position and facing to either side in the sitting position). Insert the needle in a slightly cephalad angle toward the umbilicus. Advance the needle slowly but smoothly. Occasionally, the practitioner will feel a characteristic “pop” when the needle penetrates the dura. Otherwise, the stylet should be withdrawn after approximately 4-5 cm and observed for fluid return. If no fluid returns, replace the stylet, advance or withdraw the needle a few millimeters, and recheck for fluid return. Continue this process until fluid is successfully returned.
To measure the opening pressure, the patient must be in the lateral recumbent position. After fluid returns from the needle, attach the manometer through the stopcock and note the height of the fluid column. The patient's legs should be straightened when measuring open pressure or a falsely elevated pressure will be obtained.

Collect at least 10 drops of CSF in each of the 4 plastic tubes, starting with tube #1. The CSF that is in the manometer should be used (if possible) for tube #1.

Replace the stylet and remove the needle. Clean off the skin prep solution. Apply a sterile dressing and place the patient in the supine position.



complications

Post–spinal puncture headache
bloody tap
dry tap
infections
hemorrhage
postdural cerebral herniation

CSF (bacterial)
*Polymorphs
*Cell count: 1000-5000 per mm3
*Low glucose
*Normal or elevated protein
*Gram stain positive

CSF (TB)
*Polymorphs or lympocytes or mixed
*cell count: 50-5000 permm3
*Low glucose
*Elevated protein
*Gram stain negative