Other useful facts

Non-surgical aesthetic techniques, p. 332).

   Blepharospasm: 25 units in 10 divided doses to medial and lateral lids.

   Frey’s syndrome: 5 units intradermally at 1cm distances.

   Masseteric hypertrophy: 25 units into masseter.

   Sialorrhoea/drooling: to submandibular/parotid glands up to 70 units total.

   TMJ pain dysfunction/dislocation: into lateral pterygoid muscles ± temporalis, up to 80 units each side.

   Post-operative sialocoele: parotidectomy—emerging evidence.

   Migrainous headaches.

   Cervical dystonia (torticollis).

   Doses relate to Botox® (Allergan).

Statistics

Sensitivity and specificity

Sensitivity

How good a test is at identifying those who have the disease.

Specificity

How good a test is at identifying those who do not have the disease.

Useful terms

   True positives: those with a positive test result who do have the disease.

   True negatives: those with a negative test result who do not have the disease.

   False positives: those with a positive test result who do not have the disease.

   False negatives: those with a negative test result who do have the disease.

   A sensitive test will therefore have few false negatives.

   A specific test will have few false positives.

For example, MRI of the neck in detection of nodal metastasis:

   Sensitivity is 75–80% (i.e. not very sensitive). It therefore has a significant number of false negatives. These are the nodes with micrometastasis that do not show up on MRI.

   Specificity is 90–100%. It has few false positives, i.e. those nodes that fit the radiological criteria for metastatic disease nearly always show disease at histology.

    Sensitivity = No. true positives/(No. true positives + No. false negatives)

    Specificity = No. true negatives/(No. true negatives + No. false positives)

   The positive predictive value is the proportion of patients with positive test results who are correctly diagnosed:

    PPV = No. true positives/(No. true positives + No. false positives)

The infratemporal fossa

   The infratemporal fossa is an irregularly shaped cavity, situated below and medial to the zygomatic arch.

   Previously called the pterygomaxillary space.

Boundaries

Consist of the following structures:

   Anteriorly: by the infratemporal surface of the maxilla and the ridge, which descends from its zygomatic process.

   Posteriorly: by the articular eminence of the temporal bone and the spinal angularis of the sphenoid bone.

   Superiorly: by the greater wing of the sphenoid below the infratemporal crest and the under-surface of the squamous temporal bone.

   Inferiorly: by the alveolar border of the maxilla.

   Medially: by the lateral pterygoid plate.

   Laterally: by the ramus of mandible.

   It has no floor.

Contents

Muscles

   The lower part of the temporalis muscle.

   Lateral and medial pterygoid muscle.

Vessels

   The internal maxillary vessels, consisting of the maxillary artery originating from the external carotid artery and its branches.

   Internal maxillary branches found within the infratemporal fossa including:

    •   middle meningeal artery;

    •   inferior alveolar artery;

    •   deep temporal artery;

    •   buccal artery;

    •   pterygoid venous plexus.

Nerves

Mandibular nerve, inferior alveolar nerve, lingual nerve, buccal nerve, chorda tympani nerve, and otic ganglion.

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Mar 2, 2015 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Other useful facts
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