Trismus. Trismus after anaesthesia is usually caused by intramuscular injection of the anaesthetics in the pterygomandibular space. It can occur even 2 – 5 days after
Trismus commonly referred to as “lock jaw”, is a medical condition in which the normal motion of the mandible (jaw) is reduced as a result of sustained, tetanic spasm of the masticatory muscles mediated by the trigeminal nerve.
Trismus is linked to a long list of conditions and medical issues. The most common causes are TMD, reaction to head and neck cancer treatment or after wisdom teeth removal.
Etiology. Trismus after implant surgery can be due to multiple factors. The most likely etiologic factor is local anesthetic, secondary to an inferior alveolar nerve block that penetrates the medial pterygoid muscle.
This disorder generally is treated by the application of heat, muscle stretches, analgesic and/or muscle relaxant ingestion, and a physical therapy referral. The severity of the disorder typically dictates the extent of therapy that is needed.
Trismus. Trismus after anaesthesia is usually caused by intramuscular injection of the anaesthetics in the pterygomandibular space. It can occur even 2 – 5 days after inferior alveolar block anaesthesia. Affected muscles are usually either the lateral pterygoid muscle or the temporal muscle.
The following 3 techniques are used to perform a mandibular nerve block [1, 2] : Gow-Gates technique. Vazirani-Akinosi technique. Coronoid approach.
Trismus or lock jaw due to masseter muscle spasm, can be a primary presenting symptom in tetanus, Caused by Clostridium tetani, where tetanospasmin (toxin) is responsible for muscle spasms.
After anesthesia, trismus is usually caused by intramuscular injection of the anesthetic agent into the pterygomandibular space, usually affecting either the lateral pterygoid muscle or the temporal muscle .
One simple test is the 'three finger test'. Ask the patient to insert three fingers into the mouth. If all three fingers fit between the central incisors, mouth opening is considered functional. If less than three fingers can be inserted, restriction is likely.
Trismus can be caused by damage to the muscles and/or nerve responsible for opening and closing the mouth and for chewing.
Trismus usually resolves itself in less than two weeks, but it can be very painful in the meantime.
Once trismus develops, its progression to chronic hypomobility and fibrous ankylosis may be prevented by the early institution of treatment consisting of heat, analgesics, muscle relaxants, and exercises.
Benzodiazepines may also be used, such as diazepam (2-5 mg, 3 times/day). Physiotherapy treatments may be required to establish normal function (exercises will include neck stretching, chin tuck, massaging of masticatory muscles, and other jaw stretching).
Trismus is commonly referred to as lockjaw and is usually due to sustained tetanic spasms of the muscles of mastication. Although it was initially described in the setting of tetanus, it is now used to refer to a bilateral restriction in mouth opening from any cause.
Localized responses to anesthetic injections are fairly common. Immediate local complications of lo- cal anesthesia include hematoma formation, tissue blanching, facial paralysis, amaurosis, diplopia, needle breakage, positive blood aspiration, and burning sen- sation on impingement of the nerve.
Local complications maybe due to direct nerve damage by the needle and include paraesthesia, trismus, haematoma formation and needle breakage. The systemic complications are most likely to be related to toxicity as a result of excessive administration, and rarely allergy.
The anesthetic block of the inferior alveolar nerve (IAN) is one of the most common techniques used in dental practice. The local complications are due to the failures on the anesthetic block or to anatomic variations in the tap site such as intravascular injection, skin ischemia and ocular problems.
The pterygoid lateralis, assisted by the digastric (discussed in Section Muscles of the Neck), opens the mouth by depressing and protracting the mandible.
Nerve blocks are typically categorized into four main categories. These four nerve block categories include: therapeutic, diagnostic, prognostic, and pre-emptive. Therapeutic nerve blocks are used to treat chronic pain and various pain conditions.
Mandibular nerve block involves blockage of the auriculotemporal, inferior alveolar, buccal, mental, incisive, mylohyoid, and lingual nerves. It results in anesthesia of the following areas: Ipsilateral mandibular teeth up to the midline. Buccal and lingual hard and soft tissue on the side of the block.
The inferior alveolar nerve block is the most common injection technique used in dentistry and many modifications of the conventional nerve block have been recently described in the literature.