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Technique and Procedure of Intramuscular Injection/Intramuscular Injection is the method of installing medications into the depth of the bulk of specifically selected muscles. The basis of this process is that the bulky muscles have good vascularity, and therefore the injected drug quickly reaches the systemic circulation and thereafter into the specific region of action, bypassing the first-pass metabolism.[rx] It is one of the most common medical procedures to be performed on an annual basis. However, there is still a lack of uniform guidelines and an algorithm in giving IM among health professionals across the world.[rx] [rx]

Intramuscular injection, often abbreviated IM, is the injection of a substance directly into the muscle. In medicine, it is one of several methods for parenteral administration of medications. Muscles have larger and more numerous blood vessels than subcutaneous tissue; intramuscular injections usually have faster rates of absorption than subcutaneous or intradermal injections.^[rx] The volume of injection is limited to 2-5 milliliters, depending on the injection site.

Anatomy and Physiology of Intramuscular Injection

Anatomical Landmarks

• There are specific landmarks to be taken into consideration while giving IM injections so as to avoid any neurovascular complications. The specific landmarks for the most commonly used sites are discussed below

Dorsogluteal Region

• 5 to 7.5 cm below the iliac crest.
• Upper outer quadrant of the upper outer quadrant within the buttocks[3]

Ventrogluteal Region

• The heel of the opposing hand is placed in the greater trochanter, the index finger in the anterior superior iliac spine and the middle finger below the iliac crest. The drug is injected in the triangle formed by the index, middle finger, and the iliac crest[rx][rx]

Deltoid

• 2.5 to 5 cm below the acromion process

Vastus Lateralis

• Possible sites for IM injection include – deltoid, dorsogluteal, rectus femoris, vastus lateralis and ventrogluteal muscles. Sites that are bruised, tender, red, swollen, inflamed or scarred are avoided.
• The middle third of the line joining the greater trochanter of the femur and the lateral femoral condyle of the knee[rx]

Uses of Intramuscular Injection

Drugs may be given intramuscularly both for prophylactic as well as curative purposes, and the most common medications include[rx]:

• Antibiotics- penicillin G benzathine penicillin, streptomycin
• Biologicals- immunoglobins, vaccines, and toxoids
• Hormonal agents- testosterone, medroxyprogesterone

Any drugs that are nonirritant and soluble may be given IM during an emergency scenario.

Examples of medications that are sometimes administered intramuscularly are:

• Atropine
• Haloperidol (Haldol)
• Aripiprazole (Abilify)
• Paliperidone (Invega)
• Chlorpromazine (Thorazine)
• Lorazepam (Ativan)
• Fulvestrant (Faslodex)
• Codeine
• Morphine
• Methotrexate
• Metoclopramide
• Magnesium sulfate
• Olanzapine
• Streptomycin
• Diazepam
• Prednisone
• Penicillin
• Interferon beta-1a
• Sex hormones, such as testosterone, estradiol valerate, and medroxyprogesterone acetate (as Depo Provera)
• Dimercaprol
• Ketamine
• Leuprorelin
• Naloxone
• Quinine, in its gluconate form
• Vitamin B12, as cyanocobalamin, hydroxocobalamin or methylcobalamin
• Risperidone

In addition, some vaccines are administered intramuscularly

• Gardasil
• Hepatitis A vaccine
• Rabies vaccine
• Influenza vaccines based on inactivated viruses are commonly administered intramuscularly (although there is active research being conducted as to the best route of administration).
• Platelet-rich plasma injections can be administered intramuscularly.
• Certain substances (e.g. ketamine) are injected intramuscularly for recreational purposes.

Indications of Intramuscular Injection

IM is commonly indicated for patients who are 

• Noncompliant
• Uncooperative
• Reluctant
• Unable to receive drugs through other commonly utilized routes[rx]

Contraindications of Intramuscular Injection

• Active infection, cellulitis or dermatitis at the site of administration
• Known allergy or hypersensitivity to the drug
• Acute myocardial infarction- the release of muscle enzymes may provide a confounding bias in making the diagnosis
• Thrombocytopenia
• Coagulation defects
• Hypovolemic shock- the absorption of the drug may be hampered owing to compromised vascularity to the muscle
• Myopathies
• Associated muscular atrophy- leads to delayed drug absorption as well as adds up the risk of neurovascular complications

Equipment

• 20-25 gauge syringe with a needle length of 16-38 mm
• Filter needle
• Alcohol-based antiseptic solution
• The correct drug in an appropriate dose
• Dry cotton swab
• Self-adhesive bandage
• Needle disposal unit
• A trained nurse or a paramedics
• The treating physician

Preparation

Prerequisite-

Ensure the 5 ‘Rs’

• Right patient
• Right drug
• Right dose
• Right site
• Right timing

Ask for any adverse reactions in previous such procedures.

Counseling regarding the procedure and preparing the patient– to calm them down and also to minimize the pain associated with the procedure

Site selection

• Infants- vastus lateralis
• Children- vastus lateralis and deltoid
• Adults- ventrolateral and deltoid[rx]

Drug volume

• 2 ml or less- deltoid injection
• 2 to 5 ml       – Ventrogluteal injection[rx]

Needle length

• Vastus lateralis -16 to 25 mm
• Deltoid-16 to 32 mm (children), 25 to 38 mm(adults)
• Ventrogluteal-38 mm[rx]

Technique of Intramuscular Injection

The sequential method of IM injection can be summarised as follows[rx][rx][rx]

• Thorough cleaning of the hands
• Application of sterile gloves
• Thorough cleansing surrounding the site of injection with an alcohol-based antiseptic solution
• Perpendicular insertion of a needle of appropriate sized length[rx]
• Prepare the drug and then aspirate it from the filter needle
• Insure intramuscular positioning of the needle via confirming restricted side to side movement of the needle as opposed to when the needle is in the subcutaneous plane
• Aspirate to rule out any egress of blood especially in cases of dorsogluteal injection due to inadvertent vascular puncturing of the gluteal artery during the procedure[rx][rx]
• Slow injection of the drug at 10 sec/ml
• Slow withdrawal the needle and then apply gentle pressure over the injected site with a dry cotton swab
• Proper disposal of all the equipment used during the procedure[rx]
• Assessment of  the injected region for probable early and late complications

Complications

Common complications  associated with the intramuscular injection can be summarized as [rx]:

• Muscle fibrosis and contracture
• Abscess at the injection site
• Gangrene
• Nerve injury -the sciatic nerve in gluteal injection, the femoral nerve in vastus lateralis injection
• Vascular injury- the superior gluteal nerve in dorsogluteal injection, the femoral nerve in vastus lateralis injection, radial nerve in deltoid injection
• Skin slough
• Periostitis
• Transmission of HIV, hepatitis virus
• Persistent pain at the site of injection

Clinical Significance

Advantages

• Rapid and uniform absorption of the drug especially those of the aqueous solutions
• Rapid onset of the action compared to that of the oral and the subcutaneous routes
• IM injection bypasses the first-pass metabolism
• It also avoids the gastric factors governing the drug absorption
• Has efficacy and potency comparable to that of the intravenous drug delivery system.
• Highly efficacious in emergency scenarios such as acute psychosis and status epilepticus
• Depot injections allow slow, sustained and prolonged  action
• A large volume of the drug can be administered compared to that of the subcutaneous route

 Disadvantages

• Expert and a trained person is required for administrating the drug by IM route
• The absorption of the drug is determined by the bulk of the muscle and its vascularity
• The onset and duration of the action of the drug is not adjustable
• In case of inadvertent scenarios such as anaphylaxis or neurovascular injuries, intravenous (IV) assess needs to be secured
• IM injection at the appropriate landmarks may be difficult in a child as well as in  patients requiring physical restrain
• Inadvertent injection in the subcutaneous plane of the fascia can lead to delayed action of the drug
• Painful procedure
• Suspensions, as well as oily drugs, cannot be administered
• Can lead to anxiety to the patient especially in children
• Self-administration of the drug can be difficult
• The precipitation of the drug following faster absorption of the solvent may lead to delayed and prolonged action of the drug
• Unintended prolonged sequelae following delayed drug release from the muscular compartment
• Need for temporary restraint of the patients especially in cases with children

References

Intramuscular Injection is the method of installing medications into the depth of the bulk of specifically selected muscles. The basis of this process is that the bulky muscles have good vascularity, and therefore the injected drug quickly reaches the systemic circulation and thereafter into the specific region of action, bypassing the first-pass metabolism.[rx] It is one of the most common medical procedures to be performed on an annual basis. However, there is still a lack of uniform guidelines and an algorithm in giving IM among health professionals across the world.[rx] [rx]

Intramuscular injection, often abbreviated IM, is the injection of a substance directly into the muscle. In medicine, it is one of several methods for parenteral administration of medications. Muscles have larger and more numerous blood vessels than subcutaneous tissue; intramuscular injections usually have faster rates of absorption than subcutaneous or intradermal injections.^[rx] The volume of injection is limited to 2-5 milliliters, depending on the injection site.

Anatomy and Physiology of Intramuscular Injection

Anatomical Landmarks

• There are specific landmarks to be taken into consideration while giving IM injections so as to avoid any neurovascular complications. The specific landmarks for the most commonly used sites are discussed below

Dorsogluteal Region

• 5 to 7.5 cm below the iliac crest.
• Upper outer quadrant of the upper outer quadrant within the buttocks[3]

Ventrogluteal Region

• The heel of the opposing hand is placed in the greater trochanter, the index finger in the anterior superior iliac spine and the middle finger below the iliac crest. The drug is injected in the triangle formed by the index, middle finger, and the iliac crest[rx][rx]

Deltoid

• 2.5 to 5 cm below the acromion process

Vastus Lateralis

• Possible sites for IM injection include – deltoid, dorsogluteal, rectus femoris, vastus lateralis and ventrogluteal muscles. Sites that are bruised, tender, red, swollen, inflamed or scarred are avoided.
• The middle third of the line joining the greater trochanter of the femur and the lateral femoral condyle of the knee[rx]

Uses of Intramuscular Injection

Drugs may be given intramuscularly both for prophylactic as well as curative purposes, and the most common medications include[rx]:

• Antibiotics- penicillin G benzathine penicillin, streptomycin
• Biologicals- immunoglobins, vaccines, and toxoids
• Hormonal agents- testosterone, medroxyprogesterone

Any drugs that are nonirritant and soluble may be given IM during an emergency scenario.

Examples of medications that are sometimes administered intramuscularly are:

• Atropine
• Haloperidol (Haldol)
• Aripiprazole (Abilify)
• Paliperidone (Invega)
• Chlorpromazine (Thorazine)
• Lorazepam (Ativan)
• Fulvestrant (Faslodex)
• Codeine
• Morphine
• Methotrexate
• Metoclopramide
• Magnesium sulfate
• Olanzapine
• Streptomycin
• Diazepam
• Prednisone
• Penicillin
• Interferon beta-1a
• Sex hormones, such as testosterone, estradiol valerate, and medroxyprogesterone acetate (as Depo Provera)
• Dimercaprol
• Ketamine
• Leuprorelin
• Naloxone
• Quinine, in its gluconate form
• Vitamin B12, as cyanocobalamin, hydroxocobalamin or methylcobalamin
• Risperidone

In addition, some vaccines are administered intramuscularly:

• Gardasil
• Hepatitis A vaccine
• Rabies vaccine
• Influenza vaccines based on inactivated viruses are commonly administered intramuscularly (although there is active research being conducted as to the best route of administration).
• Platelet-rich plasma injections can be administered intramuscularly.
• Certain substances (e.g. ketamine) are injected intramuscularly for recreational purposes.

Indications of Intramuscular Injection

IM is commonly indicated for patients who are

• Noncompliant
• Uncooperative
• Reluctant
• Unable to receive drugs through other commonly utilized routes[rx]

Contraindications of Intramuscular Injection

• Active infection, cellulitis or dermatitis at the site of administration
• Known allergy or hypersensitivity to the drug
• Acute myocardial infarction- the release of muscle enzymes may provide a confounding bias in making the diagnosis
• Thrombocytopenia
• Coagulation defects
• Hypovolemic shock- the absorption of the drug may be hampered owing to compromised vascularity to the muscle
• Myopathies
• Associated muscular atrophy- leads to delayed drug absorption as well as adds up the risk of neurovascular complications

Equipment

• 20-25 gauge syringe with a needle length of 16-38 mm
• Filter needle
• Alcohol-based antiseptic solution
• The correct drug in an appropriate dose
• Dry cotton swab
• Self-adhesive bandage
• Needle disposal unit
• A trained nurse or a paramedics
• The treating physician

Preparation

Prerequisite-

Ensure the 5 ‘Rs’

• Right patient
• Right drug
• Right dose
• Right site
• Right timing

Ask for any adverse reactions in previous such procedures.

Counseling regarding the procedure and preparing the patient– to calm them down and also to minimize the pain associated with the procedure

Site selection

• Infants- vastus lateralis
• Children- vastus lateralis and deltoid
• Adults- ventrolateral and deltoid[rx]

Drug volume

• 2 ml or less- deltoid injection
• 2 to 5 ml       – Ventrogluteal injection[rx]

Needle length

• Vastus lateralis -16 to 25 mm
• Deltoid-16 to 32 mm (children), 25 to 38 mm(adults)
• Ventrogluteal-38 mm[rx]

Technique of Intramuscular Injection

The sequential method of IM injection can be summarised as follows[rx][rx][rx]

• Thorough cleaning of the hands
• Application of sterile gloves
• Thorough cleansing surrounding the site of injection with an alcohol-based antiseptic solution
• Perpendicular insertion of a needle of appropriate sized length[rx]
• Prepare the drug and then aspirate it from the filter needle
• Insure intramuscular positioning of the needle via confirming restricted side to side movement of the needle as opposed to when the needle is in the subcutaneous plane
• Aspirate to rule out any egress of blood especially in cases of dorsogluteal injection due to inadvertent vascular puncturing of the gluteal artery during the procedure[rx][rx]
• Slow injection of the drug at 10 sec/ml
• Slow withdrawal the needle and then apply gentle pressure over the injected site with a dry cotton swab
• Proper disposal of all the equipment used during the procedure[rx]
• Assessment of  the injected region for probable early and late complications

Complications

Common complications  associated with the intramuscular injection can be summarized as [rx]:

• Muscle fibrosis and contracture
• Abscess at the injection site
• Gangrene
• Nerve injury -the sciatic nerve in gluteal injection, the femoral nerve in vastus lateralis injection
• Vascular injury- the superior gluteal nerve in dorsogluteal injection, the femoral nerve in vastus lateralis injection, radial nerve in deltoid injection
• Skin slough
• Periostitis
• Transmission of HIV, hepatitis virus
• Persistent pain at the site of injection

Clinical Significance

Advantages

• Rapid and uniform absorption of the drug especially those of the aqueous solutions
• Rapid onset of the action compared to that of the oral and the subcutaneous routes
• IM injection bypasses the first-pass metabolism
• It also avoids the gastric factors governing the drug absorption
• Has efficacy and potency comparable to that of the intravenous drug delivery system.
• Highly efficacious in emergency scenarios such as acute psychosis and status epilepticus
• Depot injections allow slow, sustained and prolonged  action
• A large volume of the drug can be administered compared to that of the subcutaneous route

 Disadvantages

• Expert and a trained person is required for administrating the drug by IM route
• The absorption of the drug is determined by the bulk of the muscle and its vascularity
• The onset and duration of the action of the drug is not adjustable
• In case of inadvertent scenarios such as anaphylaxis or neurovascular injuries, intravenous (IV) assess needs to be secured
• IM injection at the appropriate landmarks may be difficult in a child as well as in  patients requiring physical restrain
• Inadvertent injection in the subcutaneous plane of the fascia can lead to delayed action of the drug
• Painful procedure
• Suspensions, as well as oily drugs, cannot be administered
• Can lead to anxiety to the patient especially in children
• Self-administration of the drug can be difficult
• The precipitation of the drug following faster absorption of the solvent may lead to delayed and prolonged action of the drug
• Unintended prolonged sequelae following delayed drug release from the muscular compartment
• Need for temporary restraint of the patients especially in cases with children

References

Indications of Piriformis Steroid Injection

Piriformis syndrome may be responsible for 0.3% to 6% of all cases of low back pain and/or sciatica. With an estimated amount of new cases of low back pain and sciatica at 40 million annually, the incidence of piriformis syndrome would be roughly 2.4 million per year. In the majority of cases, piriformis syndrome occurs in middle-aged patients with a reported ratio of male to female patients being affected 1:6.

Contraindications of Piriformis Steroid Injection

Two components contribute to the clinical presentation of piriformis syndrome: somatic and neuropathic. The somatic component is a myofascial pain component of the syndrome secondary to any of the surrounding muscles/fascia (i.e. any of the short external rotators of the hip). The neuropathic component refers to the compression or irritation of the sciatic nerve as it courses through above, near, or through, the piriformis muscle itself.

Patients may present acutely in cases of post-traumatic piriformis syndrome or insidiously as in cases of overuse or myofascial pain. Patients will report having gluteal pain with possible associated paresthesias in the back, groin, perineum, buttocks, hip, back of the thigh, calf, foot, and rectum. There is also intense and worsened pain with sitting or squatting.

Preparation of Piriformis Steroid Injection

Initial evaluation should start with a lumbar spine examination. The examination should take into account the patient’s gait, posture, and alignment as well as any leg length discrepancies. Also, the practitioner should examine the patient’s hips, pelvis, and the sacroiliac joint, noting sensory, motor, and deep tendon reflexes.

In piriformis syndrome, sensory, motor, and deep tendon reflexes are normal. The piriformis should be palpated as well just posterior to the hip joint and in the area of the greater sciatic notch.   Straight leg raise may also be positive although there is variable sensitivity and specificity for this provocative maneuver.

There are individual tests that stretch the piriformis and can be used to help aid in the diagnosis of exclusion. One of these is the Freiberg sign, which is performed by putting the hip in extension and internal rotation and having the patient externally rotate against resistance. The positive exam will reproduce pain around the piriformis. This test will have positive results in up to 63% of patients. Another individual test called the Pace sign is performed by resisting abduction and external rotation of the hip while the patient is in a seated position. Pace sign occurs in 30% to 74% in piriformis syndrome. FAIR test or also known as the piriformis stretch may elicit pain. Beatty sign has also been described and is accomplished by elevating the flexed leg on the irritated side while the patient lies on the asymptomatic side. Pain and reproduction of the symptoms are a positive test result.

Technique

No definitive diagnostic criteria has been validated and established for piriformis syndrome.  It remains a diagnosis of exclusion, but many of the following exam findings can aid the clinician in honing in on this diagnosis:

• Unilateral or bilateral buttock pain with fluctuating periods of pain throughout the day
• No lower back pain,
• No pain upon palpation of axial spine
• Negative results for straight leg raise
• Prolonged sitting triggering gluteal pain or sciatica
• Fluctuating sciatica through the course of the day
• Buttock pain near projection of the piriformis reproduced by FAIR or Freiberg sign or Beatty sign, or palpitations
• The absence of perineal irradiation
• Sciatica reproduced by FAIR, Freiberg sign, or Beatty sign.

Standard radiographs of the pelvis and hip should be done to rule out underlying hip pathology. MRI of the lumbar spine is also recommended to evaluate for a discogenic causes of lumbar radiculopathy and to rule out other sources of compression (e.g. soft tissue tumors or masses).  MRI can also evaluate for spinal stenosis, herniated disks, facet arthrosis, SI joint pathology, occult pelvic fractures, and any surrounding tendinopathies or bursitides.

EMG is often normal in patients with acute piriformis syndrome presentations, however, chronically, EMG/NCS can be useful in identifying neuropathic changes and abnormal results in muscles innervated by the sciatic nerve [rx].

Solution (injectable):

• Corticosteroids: 40-mg of Depo-Medrol or Kenalog
• Local anesthetics: 3-5-ml of local anesthetic such as lidocaine or bupivacaine
• It is also done with botulinum toxin for longer relief than steroid and local anesthetic.

Patient Position: Prone

Fluoroscopy starting position:

• An A-P view is adjusted so that the inferior part of the sacroiliac joint is in the middle of the screen.

Piriformis Muscle Injection with Fluoroscopic Guidance

• 18-gauge 1.5″ needle tip is placed on the cleaned skin over the inferior SI joint.
• Create a skin wheal and then anesthetize the deeper subcutaneous skin with 1% lidocaine and a 27-gauge 1.25-inch needle.
• A 22-gauge 3.5″ or 5″ Quincke needle is used to contact the very tip of the inferior sacroiliac joint. As the procedure is performed, note of the approximate needle depth.
• After injection, the needle is withdrawn and redirected to a target site 1-cm inferior, 1-cm lateral, and 1-cm deeper than the SI joint.

Caution: Never inject if the patient feels a sharp pain shooting down their leg as the needle tip may be inside the sciatic nerve. The needle should be repositioned and then retry.

Complications

Nonoperative

Treatment for piriformis syndrome begins with nonoperative modalities including:

• Oral analgesics (e.g. NSAIDs, muscle relaxants, and gabapentin)
• Physical therapy:

  • Regimens include nerve stretches, isometric exercises, gluteal muscle strengthening
• Injections

  • Diagnostic and therapeutic modalities
  • Agents used include cortisone, local anesthetic, or botulinum toxin
  • A recent study reported positive outcomes in patients managed with physical therapy and Botulinum toxin injection

Surgical treatment

• Surgery is considered in refractory cases after exhausting nonoperative modalities
• A 2005 study reported surgical outcomes in 64 patients managed with surgical intervention for refractory symptoms: [rx]

  • 82% reported initial improvement
  • 76% had long-term positive outcomes
  • 92% of those managed with surgery returned to work or presurgical baseline activity levels within 2 weeks of the surgery

References

• https://www.ncbi.nlm.nih.gov/books/NBK532946/
• https://www.ncbi.nlm.nih.gov/books/NBK534766/
• https://www.ncbi.nlm.nih.gov/books/NBK537340/
• https://www.ncbi.nlm.nih.gov/books/NBK532891/
• https://pubmed.ncbi.nlm.nih.gov/29763092/

• https://pubmed.ncbi.nlm.nih.gov/28613525/
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4481672/
• https://pubmed.ncbi.nlm.nih.gov/11159077/
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1002105/
• https://pubmed.ncbi.nlm.nih.gov/26137182/
• https://radiopaedia.org/articles/baker-cyst-2
• https://www.medicalnewstoday.com/articles/327497
• https://www.physio-pedia.com/Baker%27s_Cyst
• https://www.mayoclinic.org/diseases-conditions/bakers-cyst/diagnosis-treatment
• https://www.healthline.com/health/bakers-cyst
• https://www.nhs.uk/conditions/bakers-cyst/treatment/
• https://www.health.harvard.edu/knees/how-do-you-treat-a-bakers-cyst
• https://www.medicinenet.com/baker_cyst/article.htm

• https://pubmed.ncbi.nlm.nih.gov/28613525/
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4481672/
• https://pubmed.ncbi.nlm.nih.gov/11159077/
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1002105/
• https://pubmed.ncbi.nlm.nih.gov/26137182/
• https://radiopaedia.org/articles/baker-cyst-2
• https://www.medicalnewstoday.com/articles/327497
• https://www.physio-pedia.com/Baker%27s_Cyst
• https://www.mayoclinic.org/diseases-conditions/bakers-cyst/diagnosis-treatment
• https://www.healthline.com/health/bakers-cyst
• https://www.nhs.uk/conditions/bakers-cyst/treatment/
• https://www.health.harvard.edu/knees/how-do-you-treat-a-bakers-cyst
• https://www.medicinenet.com/baker_cyst/article.htm

• https://pubmed.ncbi.nlm.nih.gov/28613525/
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4481672/
• https://pubmed.ncbi.nlm.nih.gov/11159077/
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1002105/
• https://pubmed.ncbi.nlm.nih.gov/26137182/
• https://radiopaedia.org/articles/baker-cyst-2
• https://www.medicalnewstoday.com/articles/327497
• https://www.physio-pedia.com/Baker%27s_Cyst
• https://www.mayoclinic.org/diseases-conditions/bakers-cyst/diagnosis-treatment
• https://www.healthline.com/health/bakers-cyst
• https://www.nhs.uk/conditions/bakers-cyst/treatment/
• https://www.health.harvard.edu/knees/how-do-you-treat-a-bakers-cyst
• https://www.medicinenet.com/baker_cyst/article.htm

• https://pubmed.ncbi.nlm.nih.gov/10461713/
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1396614/
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3199694/
• https://www.sciencedirect.com/science/article/pii/S0741521499700984
• https://www.sciencedirect.com/science/article/pii/S1078588415008898
• https://opencardiovascularmedicinejournal.com/VOLUME/12/PAGE/18/FULLTEXT/
• https://www.mayoclinic.org/diseases-conditions/popliteal-artery-entrapment/symptoms-causes/syc-20465211
• https://en.wikipedia.org/wiki/Popliteal_artery_entrapment_syndrome

Physical exploration

• Clinical signs and symptoms of Achilles Tendonitis include localized pain, focal or diffuse sensitivity,  swelling, stiffness/morning pain, perceived rigidity in the Achilles’ tendon, positive arc sign, Royal London Hospital test, and Thompson test.

Tests used to diagnose Achilles tendinopathy

• Lateral and axial calcaneus x-rays – May detect calcifications in the proximal extension of the tendon insertion or bony prominences in the upper portion of the calcaneus. Also, x-rays can help exclude pathological bone tumors.[rx][rx][rx]
• Ultrasound – Can help assess injury to the tendon[rx]; can be used to predict the risk of tendinopathy and rupture.[rx] Ultrasound may reveal the increased thickness of the Achilles tendon with hyperemia associated with hypervascularity, a decrease in the gastrocnemius-soleus rotation angle and a decrease in the length of the Kager fat pad. Ultrasound is also useful during interventional treatment.[rx]
• Magnetic Resonance Imaging – Provides significant information about the state of joint structures with a study in multiple planes in static and dynamic views.[rx][rx] One study found that MRI had lower sensitivity than ultrasound in the detection of early changes of enthesopathy.[rx]. Another study found an excellent agreement between tendon thickness measurement between magnetic resonance and ultrasound.[rx]
• Computed Tomography (CT) – The CT scan is useful to rule out trabecular structural alterations of the calcaneus in Achilles pathology of insertion. However, it exposes the patient to radiation.[rx][rx][rx]
• Victoria Institute of Sports Assessment – Achilles (VISA-A) remains the gold standard for assessing pain and function,[rx] but it requires additional studies to increase its reliability.[rx] Nevertheless, it is an essential tool for patient post-treatment follow-up.

Differential Diagnosis

• Achilles bursitis
• Ankle fracture
• Ankle impingement syndrome
• Ankle osteoarthritis
• Ankle sprain
• Calf injuries
• Calcaneofibular ligament injury
• Calcaneus fractures
• Deep venous thrombosis (DVT)
• Exertional Compartment Syndrome
• Fascial tears
• Gastrocsoleus muscle strain or rupture
• Haglund deformity
• Plantaris tendon tear
• Psoriatic arthritis
• Reiter syndrome
• Retrocalcaneal bursitis
• Ruptured Baker cyst
• Syndesmosis
• Talofibular Ligament Injury

Treatment of Achilles Tendinopathy

Management of Achilles tendinopathy can divide into conservative and surgical. Additionally, one must consider whether it is an acute or chronic condition. Finally, for those with a full rupture, the treatment is usually surgical.

Conservative therapy:  It is the first line of management and includes the following[rx][rx][rx][rx][rx][rx]

• Reduction of activity levels
• Adaptation of footwear, manual therapy directed at local sites may enhance the rehabilitation
• Eccentric stretching exercises should comprise an integral component of physiotherapy and can achieve a 40% reduction in pain; moderate level evidence favors eccentric exercise over concentric exercise for reducing pain
• Tendon loading exercise at short- and long-term follow-up
• If unresponsive to initial management, extracorporeal shock wave therapy reduces pain by 60%, with 80% patient satisfaction, improving functionality and quality of life, with a follow-up at 4 weeks; this might be the first choice because of its safety and effectiveness
• Physiotherapy improves the pain and functionality of the Achilles tendinopathy of the middle portion; however, studies do not show preferences for any particular exercise over another – overall, use of a splint to an eccentric exercise protocol or the use of orthoses to improve pain and function is not a recommendation
• Current evidence shows a lack of efficacy on the use of platelet-rich plasma for Achilles tendinopathy

Nonoperative Management

• Braces and immobilization – with a cast or pneumatic walking boot are combined with modified activity [rx]. Immobilization is frequently used in the acute setting to control exacerbating factors, but prolonged immobilization should be avoided[rx].
• Ultrasound – is a commonly prescribed program of physical therapy. In animal studies, ultrasound could stimulate collagen synthesis in tendon fibroblasts and cell division during the period of rapid cell proliferation [rx]. Therapeutic ultrasound has been shown to reduce the swelling in the acute inflammatory phase of soft-tissue disorders, relieve pain, and increase function in patients with chronic tendon injuries and may enhance tendon healing [rx, rx].
• Low-level laser therapy (LLLT) – could reduce the expression of proinflammatory markers such as IL-6 and TNF-α in gene level [rx]. In the cellular level, LLLT may increase collagen production [rx], stimulate tenocyte proliferation [rx], downregulate MMPs, decrease the capillary flow of neovascularization, and finally preserve the resistance and elasticity of tendon [rx, rx].
• Extracorporeal shockwave therapy (ESWT) – How ESWT works is still poorly understood, but it is known to cause selective dysfunction of sensory unmyelinated nerve fibers, alteration in the dorsal root ganglia, and cavitation in interstitial and extracellular disruption, which could promote the healing response [rx].
• Deep friction massage (DFM) – and tendon mobilization may also be helpful in the treatment of Achilles tendinopathy. DFM has been advocated for tendinopathy and para tendinopathy. Friction has been shown to increase the protein output of tendon cells [rx]. In combination with stretching, deep friction massage helps to restore tissue elasticity and reduce the strain in the muscle-tendon unit [rx, rx]. Future randomized comparison studies are necessary to compare DFM in isolation with other modes of treatment.
• Cryotherapy – might play a role in reducing the increased capillary blood flow in Achilles tendinopathy, reducing the metabolic rate of the tendon, and applying for relief of pain [rx, rx]. However, recent evidence in upper limb tendinopathy indicated that the addition of ice did not offer any advantage over an exercise program consisting of eccentric and static stretching exercises [rx].

Medication

• NSAIDs – used in chronic tendinopathy is questionable because the histological examination in the tendinopathic tissue shows no inflammatory cells [rx]. The benefits of NSAIDs use are relieving pain in the acute phase and reducing the possibility of leg stiffness [rx]. However, there are some studies that indicated that the NSAIDs may inhibit tendon cell migration and proliferation and impair tendon healing [rx].
• Corticosteroid injections – are reported to reduce pain and swelling and improve the ultrasound appearance of the tendon. The mechanism behind any positive effect of local steroids on chronic Achilles tendinopathy remains unclear. Some authors have hypothesized that any beneficial effects of corticosteroids in this condition are owed to other local steroid effects rather than suppression of inflammation, including lyses of tendon and peritendon adhesions or alteration of the function of pain generating nociceptor in the region [rx].
• Platelet-rich plasma (PRP) – at the site of tendon injury is thought to facilitate healing because it contains several different growth factors and other cytokines that can stimulate the healing of soft tissue [rx]. Animal studies indicated that PRP could increase the expression of collagen types I and III and vascular endothelial growth factor and improve the healing and remodeling process of the tendon [rx, rx].
• Intratendinous hyperosmolar dextrose (prolotherapy) – is thought to produce a local inflammatory response and an increase in tendon strength. Clinical results indicated that intratendinous injections of hyperosmolar dextrose could reduce the pain at rest and during tendon-loading activities in patients with chronic of the Achilles tendinopathy [rx, rx]. Moreover, after the injection of dextrose, there were reductions in the size and severity of hypoechoic regions and intratendinous tears and improvements in neovascularity [rx].
• Nitric oxide – is a small-free radical generated by a family of enzymes, the nitric oxide synthases. It can induce apoptosis in inflammatory cells and cause angiogenesis and vasodilation. Moreover, oxygen-free radicals can stimulate fibroblast proliferation [rx]. Nitric oxide can enhance tendon healing. Inhibition of nitric oxide synthase can reduce the healing process, which resulted in a decreased cross-sectional area and reduced failure load [rx].
• The sclerosing agent – that selectively targets the vascular may cause thrombosis of the vessel. As the concomitant sensory nerves have been implicated as possible pain generators, to destroy local nerves adjacent to neovessels may decrease pain [rx]. As vessel number has been shown to correlate with tendon thickness, a treatment that decreases vessel number is likely to also affect the tendon thickness. Moreover, the sclerosing agent injected at multiple sites around the tendon and neovessels initiates a local inflammatory response, which induces the proliferation of fibroblasts and the synthesis of collagen.
• Aprotinin – is a broad-spectrum serine protease inhibitor capable of blocking trypsin, plasmin, kallikrein, and a range of MMPs [rx]. Most previous studies using Aprotinin injection in the management of Achilles tendinopathy showed a trend towards improved clinical results [rx, rx]. The major potential negative of using Aprotinin is the side effect of allergy [rx], but the allergic reactions can be reduced by minimizing repeat injections and recommending a delay of at least 6 weeks between injections [rx].
• Autologous blood injections – results have not been highly encouraging and there is little evidence for their use.^[rx]

Surgery

Surgical therapy is optional for 10 to 30% of patients who fail conservative therapy after six months.[rx][rx] The success rate is higher than 70%, but reports show complication rates of 3 to 40%.[rx] The Achilles tendon should undergo reattachment with a tendon rupture of more than 50%.[rx]

Noninsertional Achilles Tendonitis

• The goal of surgery is to resect degenerative tissue, stimulate tendon healing by means of controlled, low-grade trauma, and/or augment the Achilles tendon with grafts. It has been suggested that noninvasive treatment should be tried for at least 4 months prior to operative interventions [rx]. Conventional surgical treatment has consisted of open release of adhesions with or without resection of the paratenon. If >50% of the tendon has been debrided, augmentation or reconstruction is recommended [rx].

Insertional Achilles Tendonitis

• Patients who do not respond to conservative treatment may need operative management [rx]. The operative strategy for insertional Achilles tendinopathy is the removal of the degenerative tendon and associated calcification, excision of the inflamed retrocalcaneal bursa, resection of the prominent posterior calcaneal prominence, reattachment of the insertion as required, and/or augmentation of the tendo-Achilles with a tendon transfer/graft [rx, rx]. Calcaneoplasty and resection of the retrocalcaneal bursa can be performed endoscopically [rx].

Complications

Re-rupture

• While newer level 1 evidence has reported no difference in re-rupture rates, prior studies have suggested a 10% to 40% re-rupture rate with nonoperative management (compared to 1% to 2% rate of re-rupture after surgery)

• Lantto et al. recently demonstrated in a randomized controlled trial of 60 patients from 2009 to 2013 at 18-month follow-up: [rx]

  • Similar Achilles tendon performance scores
  • Slightly increased calf muscle strength differences favoring the operative cohort (10% to 18% strength difference) at 18-month follow-up
  • Slightly better health-related quality of life scores in the domains of physical functioning and bodily pain favoring the operative cohort

Wound Healing Complications

• Overall, a 5-10% risk following surgery

• Risk factors for postoperative wound complications include:

  • Smoking (most common and most significant risk factor)
  • Female gender
  • Steroid use
  • Open technique (vs percutaneous procedures)

Sural Nerve Injury

• Increased rate of injury associated with the percutaneous procedure (compared to open technique)

References

SLR Test/The straight leg raise test also called the Lasegue test is a fundamental neurological maneuver during the physical examination of the patient with lower back pain aimed to assess the sciatic compromise due to lumbosacral nerve root irritation. This test which was first described by Dr. Lazarevic and wrongly attributed to Dr. Lasegue can be positive in a variety of conditions, being lumbar disc herniation the most common. Nonetheless, there are multiple causes of a positive test such as facet joint cyst or hypertrophy.[rx][rx][rx]. Overall, this test is one of the most commonly performed maneuvers across clinical practice and provides important information when making the clinical decision to refer a patient to a specialist as well as among spinal surgeons to guide therapeutic decision-making.[rx]

Lasegue sign or Straight Leg Raising Test (SLRT) is a neurodynamic exam to assess nerve root irritation in the lumbosacral area.[rx] It is an integral element to the neurological exam for patients presenting with low back pain with or without radicular pain. The other less commonly used name is Lazarevic sign.

Anatomy and Physiology of Straight Leg Raising Test (SLRT)

The Lasegue test is basically a provocation test that evidences radicular irritation in the lumbosacral region by lower limb flexion and can be due to multiple causes. Radicular symptoms are primarily produced by nerve root inflammation by surrounded structures.[rx] The foramina are formed by the pedicle superiorly and inferiorly, ligamentum flavum posteriorly, disc and vertebral body anteriorly, and this small space normally allows the nerve root excursion of 4 mm, however during the straight leg raise test this root excursion can be compromised by several factors. Mechanical compression solely does not always generate radicular symptoms as many patients have asymptomatic foraminal stenosis in MRI,[rx][rx] therefore, positive leg raise test may undergo influence by nerve root irritation secondary to inflammation as well as mechanical compression.

The straight leg raise test is attributed to Charles Lasegue, a French clinician who described two cases of sciatica aggravated by weight-bearing, hip, and knee flexion in “Thoughts of Sciatica” in 1864. Nonetheless, Dr. Lasegue did not describe the test as a provoked pain; instead, his student JJ Forst described the test in his doctoral thesis in 1881, and it was Forst who considered the pain to be produced by hamstring muscle compression to the sciatic nerve.

Nevertheless, it is believed that a Serbian neurologist, Dr. Lazar Lazarevic,[rx] was the first who documented the straight leg raise test as it is known today in the article named “Ischiac postica council”, initially published in the Serbian Archives of Medicine (1880), and republished in Vienna (1884). Dr. Lazarevic described the straight-leg-raising test by explaining sciatic pain by stretching the sciatic nerve based on his experience with six patients. Based on this misinterpretation of the original description, it is recommended to describe the maneuver as the straight leg raise test.

Indications of Straight Leg Raising Test (SLRT)

• PLID
• Low back pain
• Buttock pain
• Leg pain
• Lumbago
• Low back pain

The Technique of Straight Leg Raising Test (SLRT)

The straight leg raise test is performed with the patient in a supine position. The examiner gently raises the patient’s leg by flexing the hip with the knee in extension, and the test is considered positive when the patient experiences pain along the lower limb in the same distribution of the lower radicular nerve roots (usually L5 or S1).

Furthermore, a positive straight leg raise test is determined when pain is elicited by lower limb flexion in an angle lower than 45 degrees. During the test, if the pain is reproduced during the leg straightening, patients usually request that the examiner aborts the maneuver and by flexing the patient’s knee, the buttock pain is usually relieved(Figure 1).

Additional maneuvers have been described to enhance the sensitivity of the test such as the Bragaad’s sign, which consists of concomitant foot dorsiflexion to increase the pain while the examiner completes the leg raise.

An additional maneuver is the crossed straight leg test (crossed over Lasegue), in which the examiner passively flexes the patient’s uninvolved limb while maintaining the knee in extension. A positive test is when the patient reports pain in the involved limb at 40 degrees of hip flexion with the uninvolved limb. A crossed straight test is positive in central disc herniation in cases of severe nerve root irritation.[rx]

Currently, the following technique is popular in practice

The patient should be informed about the steps of the test, what to expect during the exam, and to describe the pain distribution. The patient should be examined in a neutral supine position with the head slightly extended. During the exam, the hips and legs should stay neutral. No hips abduction or adduction is allowed as well as no leg internal or external rotation is permitted. The affected leg is then passively and slowly raised by the ankle with the knee fully extended. Upon eliciting pain, the examiner stops further leg elevation and records the range of motion along with the area of pain distribution.[rx][rx]

It is noteworthy that ankle dorsiflexion during SLRT may exaggerate the pain, notwithstanding, it is not part of the Lasegue sign.[rx]

Causes of Pain While Performing SLRT

• Stretching of the sciatic nerve
• Displacement of the medulla and conus medullaris
• Nerve compression leads to sensitization at the dorsal root ganglion and posterior horn, which in turn leads to the lowering of the pain threshold.[rx]

Causes of Positive SLRT

• Nerve root irritation – Intervertebral disc prolapse being the most common cause
• Intraspinal tumor
• Inflammatory radiculopathy

Criteria for a true positive SLRT

• Radicular leg pain should occur (radiating below the knee).
• Pain occurs when the leg is between 30 and 60 or 70 degrees from horizontal.[rx][rx]

What findings should not qualify as a positive SLRT?

• Pain occurring in the low back alone.
• Pain occurring in the posterior thigh alone.
• Pain occurring at an angle less than 30 degrees – May indicate non-organicity or hip joint pathology.
• Pain occurring at an angle more than 70 degrees from the horizontal – More likely cause is tight hamstring or gluteal muscles.
• Pain occurs in a normal person at an angle of 80 to 90 degrees.

Issues of Concern of Straight Leg Raising Test (SLRT)

SLRT modifications and its variants: the accuracy of SLRT can be better if it is interpreted with other nerve root tension tests:

• Crossed SLRT – AKA well-leg raising test or Fajersztajn sign. When the contralateral leg is lifted, the patient experiences pain on the affected side. This test is more specific than ipsilateral SLRT.[rx][rx] It becomes positive usually in severe compression and centrally located prolapse. Fajersztajn believed that this sign is due to disc prolapse in the axilla of the root.[rx]
• Reverse SLRT – AKA femoral stretch or Ely test. While the patient is in a prone position, the leg is lifted off the table with both hip and knee joints extended. Some authors may allow knee flexion. This maneuver may reproduce radicular pain in case of upper lumbar radiculopathy, far lateral lumbar disc, or femoral neuropathy. The pain will present in the femoral nerve distribution on the side of the lesion.[rx]
• Braggard test – AKA Sciatic stretch test or Flip test. While raising the leg, the foot is held in a dorsiflexed position, so that the sciatic nerve is stretched more, thereby increasing the intensity of pain or making it possible to elicit the sign early.[rx][rx]
• Reverse flip test – While raising the leg, the foot is held in a plantar-flexed position; this will lessen the pain. But if the patient is complaining of an increase in pain, it can suggest malingering.
• Bowstring sign – Also known as the popliteal compression test or posterior tibial nerve stretch sign. The patient can be examined in sitting or in a supine position. The examiner flexes the knee and applies pressure on the popliteal fossa, evoking sciatica. Some examiners do it after SLRT by flexing the knee to relieve the buttock pain. The pain would be reproduced by a quick snap on the posterior tibial nerve in the popliteal fossa.[rx]

Less frequently used nerve root irritation tests

For the sake of completion, other tests and signs of nerve root tension or irritation are discussed succinctly below:

• Sitting SLRT (Bechterew test) – the patient is made to sit at the edge of a table with both hip and knee flexed, then made to extend the knee joint or elevate the extended knee, which reproduces the radicular pain. He/she may be able to extend each leg alone, but extending both together causes radicular pain.[rx]
• Distracted SLRT – the sitting SLRT is performed without the patient’s awareness. The patient is distracted as if the surgeon is examining the foot or pulsation, and slowly, the examiner extends the knee. If the patient is experiencing true radiculopathy, the same pain will be reproduced. Otherwise, we can assume that the patient may be malingering.
• Neri’s sign – while bending forward, the patient flexes the knee to avoid stretching the nerve.[rx]
• The buckling sign – the patient may flex the knee during SLRT to avoid sciatic nerve tension.
• Sicard sign – passive dorsiflexion of ipsilateral great toe just at the angle of SLRT will produce more pain.[rx]
• Kraus-Weber test – the patient may be able to do a sit-up with the knees flexed but not extended.
• Minor sign – the patient may rise from a seated position by supporting himself/herself on the unaffected side, bending forward, and placing one hand on the affected side of the back.
• Bonnet phenomenon – the pain may be more severe or elicited sooner if the test is carried out with the thigh and leg in a position of adduction and internal rotation.

Clinical Significance of Straight Leg Raising Test (SLRT)

Interpretation of SLRT

• Pain radiating down the buttock to the lateral thigh and medial calf – L4 nerve root irritation
• Pain radiating down the buttock to the posterior thigh and lateral calf – L5 nerve root irritation
• Pain radiating down the buttock to the posterior thigh and calf, and lateral foot – S1 nerve root irritation

Interpretation of Positive Reverse SLRT

• L2, L3 or L4 root irritation
• Femoral nerve irritation

Sensitivity and Specificity of the Test

The sensitivity of ipsilateral SLRT is 72 to 97%, and specificity is 11 to 66%; whereas the crossed SLRT  sensitivity is 23 to 42%  which is less than ipsilateral SLRT but more specific (85 to 100%).[rx]

Tests to Confirm Non-organicity While Performing SLRT

• Pain occurring at an angle less than 30 degrees
• A significant discrepancy between the supine and sitting SLRT
• Touch-me-not or Waddell sign – Widespread and excessive tenderness
• Back pain on pressing down on the top of the head
• Overreaction during testing
• Non-dermatomal and non-myotomal neurologic signs
• Pain during simulated spinal rotation: The patient’s hands remain to the sides with hips rotated. There will not be any spine rotation with this maneuver. But the patient will complain of pain.

References

Lasegue sign/Straight Leg Raising Test (SLRT)/The straight leg raise test also called the Lasegue test is a fundamental neurological maneuver during the physical examination of the patient with lower back pain aimed to assess the sciatic compromise due to lumbosacral nerve root irritation.  Nonetheless, there are multiple causes of a positive test such as facet joint cyst or hypertrophy.[rx][rx][rx]. Overall, this test is one of the most commonly performed maneuvers across clinical practice and provides important information when making the clinical decision to refer a patient to a specialist as well as among spinal surgeons to guide therapeutic decision-making.[rx]

Lasegue sign or Straight Leg Raising Test (SLRT) is a neurodynamic exam to assess nerve root irritation in the lumbosacral area.[rx] It is an integral element to the neurological exam for patients presenting with low back pain with or without radicular pain. The other less commonly used name is Lazarevic sign.

Anatomy and Physiology of Straight Leg Raising Test (SLRT)

The Lasegue test is basically a provocation test that evidences radicular irritation in the lumbosacral region by lower limb flexion and can be due to multiple causes. Radicular symptoms are primarily produced by nerve root inflammation by surrounded structures.[rx] The foramina are formed by the pedicle superiorly and inferiorly, ligamentum flavum posteriorly, disc and vertebral body anteriorly, and this small space normally allows the nerve root excursion of 4 mm, however during the straight leg raise test this root excursion can be compromised by several factors. Mechanical compression solely does not always generate radicular symptoms as many patients have asymptomatic foraminal stenosis in MRI,[rx][rx] therefore, positive leg raise test may undergo influence by nerve root irritation secondary to inflammation as well as mechanical compression.

The straight leg raise test is attributed to Charles Lasegue, a French clinician who described two cases of sciatica aggravated by weight-bearing, hip, and knee flexion in “Thoughts of Sciatica” in 1864. Nonetheless, Dr. Lasegue did not describe the test as a provoked pain; instead, his student JJ Forst described the test in his doctoral thesis in 1881, and it was Forst who considered the pain to be produced by hamstring muscle compression to the sciatic nerve.

Nevertheless, it is believed that a Serbian neurologist, Dr. Lazar Lazarevic,[rx] was the first who documented the straight leg raise test as it is known today in the article named “Ischiac postica council”, initially published in the Serbian Archives of Medicine (1880), and republished in Vienna (1884). Dr. Lazarevic described the straight-leg-raising test by explaining sciatic pain by stretching the sciatic nerve based on his experience with six patients. Based on this misinterpretation of the original description, it is recommended to describe the maneuver as the straight leg raise test.

Indications of Straight Leg Raising Test (SLRT)

• PLID
• Low back pain
• Buttock pain
• Leg pain
• Lumbago
• Low back pain

The Technique of Straight Leg Raising Test (SLRT)

The straight leg raise test is performed with the patient in a supine position. The examiner gently raises the patient’s leg by flexing the hip with the knee in extension, and the test is considered positive when the patient experiences pain along the lower limb in the same distribution of the lower radicular nerve roots (usually L5 or S1).

Furthermore, a positive straight leg raise test is determined when pain is elicited by lower limb flexion in an angle lower than 45 degrees. During the test, if the pain is reproduced during the leg straightening, patients usually request that the examiner aborts the maneuver and by flexing the patient’s knee, the buttock pain is usually relieved(Figure 1).

Additional maneuvers have been described to enhance the sensitivity of the test such as the Bragaad’s sign, which consists of concomitant foot dorsiflexion to increase the pain while the examiner completes the leg raise.

An additional maneuver is the crossed straight leg test (crossed over Lasegue), in which the examiner passively flexes the patient’s uninvolved limb while maintaining the knee in extension. A positive test is when the patient reports pain in the involved limb at 40 degrees of hip flexion with the uninvolved limb. A crossed straight test is positive in central disc herniation in cases of severe nerve root irritation.[rx]

Currently, the following technique is popular in practice

The patient should be informed about the steps of the test, what to expect during the exam, and to describe the pain distribution. The patient should be examined in a neutral supine position with the head slightly extended. During the exam, the hips and legs should stay neutral. No hips abduction or adduction is allowed as well as no leg internal or external rotation is permitted. The affected leg is then passively and slowly raised by the ankle with the knee fully extended. Upon eliciting pain, the examiner stops further leg elevation and records the range of motion along with the area of pain distribution.[rx][rx]

It is noteworthy that ankle dorsiflexion during SLRT may exaggerate the pain, notwithstanding, it is not part of the Lasegue sign.[rx]

Causes of Pain While Performing SLRT

• Stretching of the sciatic nerve
• Displacement of the medulla and conus medullaris
• Nerve compression leads to sensitization at the dorsal root ganglion and posterior horn, which in turn leads to the lowering of the pain threshold.[rx]

Causes of Positive SLRT

• Nerve root irritation – Intervertebral disc prolapse being the most common cause
• Intraspinal tumor
• Inflammatory radiculopathy

Criteria for a true positive SLRT

• Radicular leg pain should occur (radiating below the knee).
• Pain occurs when the leg is between 30 and 60 or 70 degrees from horizontal.[rx][rx]

What findings should not qualify as a positive SLRT?

• Pain occurring in the low back alone.
• Pain occurring in the posterior thigh alone.
• Pain occurring at an angle less than 30 degrees – May indicate non-organicity or hip joint pathology.
• Pain occurring at an angle more than 70 degrees from the horizontal – More likely cause is tight hamstring or gluteal muscles.
• Pain occurs in a normal person at an angle of 80 to 90 degrees.

Issues of Concern of Straight Leg Raising Test (SLRT)

SLRT modifications and its variants: the accuracy of SLRT can be better if it is interpreted with other nerve root tension tests:

• Crossed SLRT – AKA well-leg raising test or Fajersztajn sign. When the contralateral leg is lifted, the patient experiences pain on the affected side. This test is more specific than ipsilateral SLRT.[rx][rx] It becomes positive usually in severe compression and centrally located prolapse. Fajersztajn believed that this sign is due to disc prolapse in the axilla of the root.[rx]
• Reverse SLRT – AKA femoral stretch or Ely test. While the patient is in a prone position, the leg is lifted off the table with both hip and knee joints extended. Some authors may allow knee flexion. This maneuver may reproduce radicular pain in case of upper lumbar radiculopathy, far lateral lumbar disc, or femoral neuropathy. The pain will present in the femoral nerve distribution on the side of the lesion.[rx]
• Braggard test – AKA Sciatic stretch test or Flip test. While raising the leg, the foot is held in a dorsiflexed position, so that the sciatic nerve is stretched more, thereby increasing the intensity of pain or making it possible to elicit the sign early.[rx][rx]
• Reverse flip test – While raising the leg, the foot is held in a plantar-flexed position; this will lessen the pain. But if the patient is complaining of an increase in pain, it can suggest malingering.
• Bowstring sign – Also known as the popliteal compression test or posterior tibial nerve stretch sign. The patient can be examined in sitting or in a supine position. The examiner flexes the knee and applies pressure on the popliteal fossa, evoking sciatica. Some examiners do it after SLRT by flexing the knee to relieve the buttock pain. The pain would be reproduced by a quick snap on the posterior tibial nerve in the popliteal fossa.[rx]

Less frequently used nerve root irritation tests

For the sake of completion, other tests and signs of nerve root tension or irritation are discussed succinctly below:

• Sitting SLRT (Bechterew test) – the patient is made to sit at the edge of a table with both hip and knee flexed, then made to extend the knee joint or elevate the extended knee, which reproduces the radicular pain. He/she may be able to extend each leg alone, but extending both together causes radicular pain.[rx]
• Distracted SLRT – the sitting SLRT is performed without the patient’s awareness. The patient is distracted as if the surgeon is examining the foot or pulsation, and slowly, the examiner extends the knee. If the patient is experiencing true radiculopathy, the same pain will be reproduced. Otherwise, we can assume that the patient may be malingering.
• Neri’s sign – while bending forward, the patient flexes the knee to avoid stretching the nerve.[rx]
• The buckling sign – the patient may flex the knee during SLRT to avoid sciatic nerve tension.
• Sicard sign – passive dorsiflexion of ipsilateral great toe just at the angle of SLRT will produce more pain.[rx]
• Kraus-Weber test – the patient may be able to do a sit-up with the knees flexed but not extended.
• Minor sign – the patient may rise from a seated position by supporting himself/herself on the unaffected side, bending forward, and placing one hand on the affected side of the back.
• Bonnet phenomenon – the pain may be more severe or elicited sooner if the test is carried out with the thigh and leg in a position of adduction and internal rotation.

Clinical Significance of Lasegue sign/Straight Leg Raising Test (SLRT)

Interpretation of SLRT

• Pain radiating down the buttock to the lateral thigh and medial calf – L4 nerve root irritation
• Pain radiating down the buttock to the posterior thigh and lateral calf – L5 nerve root irritation
• Pain radiating down the buttock to the posterior thigh and calf, and lateral foot – S1 nerve root irritation

Interpretation of Positive Reverse SLRT

• L2, L3 or L4 root irritation
• Femoral nerve irritation

Sensitivity and Specificity of the Test

The sensitivity of ipsilateral SLRT is 72 to 97%, and specificity is 11 to 66%; whereas the crossed SLRT  sensitivity is 23 to 42%  which is less than ipsilateral SLRT but more specific (85 to 100%).[rx]

Tests to Confirm Non-organicity While Performing SLRT

• Pain occurring at an angle less than 30 degrees
• A significant discrepancy between the supine and sitting SLRT
• Touch-me-not or Waddell sign – Widespread and excessive tenderness
• Back pain on pressing down on the top of the head
• Overreaction during testing
• Non-dermatomal and non-myotomal neurologic signs
• Pain during simulated spinal rotation: The patient’s hands remain to the sides with hips rotated. There will not be any spine rotation with this maneuver. But the patient will complain of pain.

References