|
Retrobulbar Block
A retrobulbar block is a regional anesthetic nerve block in the retrobulbar space, which is the area located behind the globe of the eye. Injection of local anesthetic into this space constitutes the retrobulbar block. This injection provides akinesia of the extraocular muscles by blocking cranial nerves II, III, and VI, thereby preventing movement of the globe. Cranial nerve IV lies outside the muscle cone, and therefore is not affected by the local anesthesia. As a result, intorsion of the eye is still possible. It also provides sensory anesthesia of the conjunctiva, cornea and uvea by blocking the ciliary nerves. This block is most commonly employed for cataract surgery, but also provides anesthesia for other intraocular surgeries. Side effects and complications Complications associated with this block are either ocular or systemic. Local ocular complications include hematoma formation, optic nerve damage and perforation of the globe with possible blindness. Systemic co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ophthalmology
Ophthalmology (, ) is the branch of medicine that deals with the diagnosis, treatment, and surgery of eye diseases and disorders. An ophthalmologist is a physician who undergoes subspecialty training in medical and surgical eye care. Following a medical degree, a doctor specialising in ophthalmology must pursue additional postgraduate residency training specific to that field. In the United States, following graduation from medical school, one must complete a four-year residency in ophthalmology to become an ophthalmologist. Following residency, additional specialty training (or fellowship) may be sought in a particular aspect of eye pathology. Ophthalmologists prescribe medications to treat ailments, such as eye diseases, implement laser therapy, and perform surgery when needed. Ophthalmologists provide both primary and specialty eye care—medical and surgical. Most ophthalmologists participate in academic research on eye diseases at some point in their training and many inc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ciliary Nerves (other)
Ciliary nerves may refer to: * Short ciliary nerves * Long ciliary nerves The long ciliary nerves are 2-3 nerves that arise from the nasociliary nerve (itself a branch of the ophthalmic branch (CN V1) of the trigeminal nerve (CN V)). They enter the eyeball to provide sensory innervation to parts of the eye, and sympa ... {{disambig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Regional Anesthesia
Local anesthesia is any technique to induce the absence of sensation in a specific part of the body, generally for the aim of inducing local analgesia, i.e. local insensitivity to pain, although other local senses may be affected as well. It allows patients to undergo surgical and dental procedures with reduced pain and distress. In many situations, such as cesarean section, it is safer and therefore superior to general anesthesia. The following terms are often used interchangeably: * ''Local anesthesia'', in a strict sense, is anesthesia of a small part of the body such as a tooth or an area of skin. * ''Regional anesthesia'' is aimed at anesthetizing a larger part of the body such as a leg or arm. * ''Conduction anesthesia'' encompasses a great variety of local and regional anesthetic techniques. Medical A local anesthetic is a drug that causes reversible local anesthesia and a loss of nociception. When it is used on specific nerve pathways (nerve block), effects such as an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eye Surgery
Eye surgery, also known as ophthalmic surgery or ocular surgery, is surgery performed on the eye or its adnexa. Eye surgery is part of ophthalmology and is performed by an ophthalmologist or eye surgeon. The eye is a fragile organ, and requires due care before, during, and after a surgical procedure to minimize or prevent further damage. An eye surgeon is responsible for selecting the appropriate surgical procedure for the patient, and for taking the necessary safety precautions. Mentions of eye surgery can be found in several ancient texts dating back as early as 1800 BC, with cataract treatment starting in the fifth century BC. It continues to be a widely practiced class of surgery, with various techniques having been developed for treating eye problems. Preparation and precautions Since the eye is heavily supplied by nerves, anesthesia is essential. Local anesthesia is most commonly used. Topical anesthesia using lidocaine topical gel is often used for quick procedures ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hyaluronidase
Hyaluronidases are a family of enzymes that catalyse the degradation of hyaluronic acid. Karl Meyer classified these enzymes in 1971, into three distinct groups, a scheme based on the enzyme reaction products. The three main types of hyaluronidases are two classes of eukaryotic endoglycosidase hydrolases and a prokaryotic lyase-type of glycosidase. In humans, there are five functional hyaluronidases: HYAL1, HYAL2, HYAL3, HYAL4 and HYAL5 (also known as SPAM1 or PH-20); plus a pseudogene, HYAL6 (also known as HYALP1). The genes for HYAL1-3 are clustered in chromosome 3, while HYAL4-6 are clustered in chromosome 7. HYAL1 and HYAL2 are the major hyaluronidases in most tissues. GPI-anchored HYAL2 is responsible for cleaving high-molecular weight hyaluronic acid, which is mostly bound to the CD44 receptor. The resulting hyaluronic acid fragments of variable size are then further hydrolyzed by HYAL1 after being internalized into endo-lysosomes; this generates hyaluronic acid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bupivicaine
Bupivacaine, marketed under the brand name Marcaine among others, is a medication used to decrease sensation in a specific small area. In nerve blocks, it is injected around a nerve that supplies the area, or into the spinal canal's epidural space. It is available mixed with a small amount of epinephrine to increase the duration of its action. It typically begins working within 15 minutes and lasts for 2 to 8 hours. Possible side effects include sleepiness, muscle twitching, ringing in the ears, changes in vision, low blood pressure, and an irregular heart rate. Concerns exist that injecting it into a joint can cause problems with the cartilage. Concentrated bupivacaine is not recommended for epidural freezing. Epidural freezing may also increase the length of labor. It is a local anaesthetic of the amide group. Bupivacaine was discovered in 1957. It is on the World Health Organization's List of Essential Medicines. Bupivacaine is available as a generic medication. An i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lidocaine
Lidocaine, also known as lignocaine and sold under the brand name Xylocaine among others, is a local anesthetic of the amino amide type. It is also used to treat ventricular tachycardia and ventricular fibrillation. When used for local anaesthesia or in nerve blocks, lidocaine typically begins working within several minutes and lasts for half an hour to three hours. Lidocaine mixtures may also be applied directly to the skin or mucous membranes to numb the area. It is often used mixed with a small amount of adrenaline (epinephrine) to prolong its local effects and to decrease bleeding. If injected intravenously, it may cause cerebral effects such as confusion, changes in vision, numbness, tingling, and vomiting. It can cause low blood pressure and an irregular heart rate. There are concerns that injecting it into a joint can cause problems with the cartilage. It appears to be generally safe for use in pregnancy. A lower dose may be required in those with liver problems. I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peribulbar Block
Nerve block or regional nerve blockade is any deliberate interruption of signals traveling along a nerve, often for the purpose of pain relief. Local anesthetic nerve block (sometimes referred to as simply "nerve block") is a short-term block, usually lasting hours or days, involving the injection of an anesthetic, a corticosteroid, and other agents onto or near a nerve. Neurolytic block, the deliberate temporary degeneration of nerve fibers through the application of chemicals, heat, or freezing, produces a block that may persist for weeks, months, or indefinitely. Neurectomy, the cutting through or removal of a nerve or a section of a nerve, usually produces a permanent block. Because neurectomy of a sensory nerve is often followed, months later, by the emergence of new, more intense pain, sensory nerve neurectomy is rarely performed. The concept of nerve block sometimes includes ''central nerve block'', which includes epidural and spinal anaesthesia. Local anesthetic nerve b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oculocardiac Reflex
The oculocardiac reflex, also known as Aschner phenomenon, Aschner reflex, or Aschner–Dagnini reflex, is a decrease in pulse rate associated with traction applied to extraocular muscles and/or compression of the eyeball. The reflex is mediated by nerve connections between the ophthalmic branch of the trigeminal cranial nerve via the ciliary ganglion, and the vagus nerve of the parasympathetic nervous system. Nerve fibres from the maxillary and mandibular divisions of the trigeminal nerve have also been documented. These afferents synapse with the visceral motor nucleus of the vagus nerve, located in the reticular formation of the brain stem. The efferent portion is carried by the vagus nerve from the cardiovascular center of the medulla to the heart, of which increased stimulation leads to decreased output of the sinoatrial node. This reflex is especially sensitive in neonates and children, particularly during strabismus correction surgery. Oculocardiac reflex can be profou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Local Anesthetic Toxicity
A local anesthetic (LA) is a medication that causes absence of all sensation (including pain) in a specific body part without loss of consciousness, providing local anesthesia, as opposed to a general anesthetic, which eliminates all sensation in the entire body and causes unconsciousness. Local anesthetics are most commonly used to eliminate pain during or after surgery. When it is used on specific nerve pathways ( local anesthetic nerve block), paralysis (loss of muscle function) also can be induced. Classification LAs are of 2 types: *Clinical LAs: ** amino amide LAs ** amino ester LAs *Synthetic LAs **Cocaine derivatives Synthetic cocaine-derived LAs differ from cocaine because they have a much lower abuse potential and do not cause hypertension vasoconstriction (with few exceptions). The suffix "-caine" at the ends of these medication names is derived from the word "cocaine", because cocaine was formerly used as a local anesthetic. Examples Short Duration of Action ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optic Nerve
In neuroanatomy, the optic nerve, also known as the second cranial nerve, cranial nerve II, or simply CN II, is a paired cranial nerve that transmits visual system, visual information from the retina to the brain. In humans, the optic nerve is derived from optic stalks during the seventh week of development and is composed of retinal ganglion cell axons and glial cells; it extends from the optic disc to the optic chiasma and continues as the optic tract to the lateral geniculate nucleus, Pretectal area, pretectal nuclei, and superior colliculus. Structure The optic nerve has been classified as the second of twelve paired cranial nerves, but it is technically a myelinated tract of the central nervous system, rather than a classical nerve of the peripheral nervous system because it is derived from an out-pouching of the diencephalon (optic stalks) during embryonic development. As a consequence, the fibers of the optic nerve are covered with myelin produced by oligodendrocytes, r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hematoma
A hematoma, also spelled haematoma, or blood suffusion is a localized bleeding outside of blood vessels, due to either disease or trauma including injury or surgery and may involve blood continuing to seep from broken capillaries. A hematoma is benign and is initially in liquid form spread among the tissues including in sacs between tissues where it may coagulate and solidify before blood is reabsorbed into blood vessels. An ecchymosis is a hematoma of the skin larger than 10 mm. They may occur among and or within many areas such as skin and other organs, connective tissues, bone, joints and muscle. A collection of blood (or even a hemorrhage) may be aggravated by anticoagulant medication (blood thinner). Blood seepage and collection of blood may occur if heparin is given via an intramuscular route; to avoid this, heparin must be given intravenously or subcutaneously. Signs and symptoms Some hematomas are visible under the surface of the skin (commonly called bruise ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
