Bullard laryngoscope

Introduction:

Bullard laryngoscope is a rigid fiberoptic laryngoscope which aids in visualization of larynx and intubation of trachea. Hence it is a very useful tool in the management of difficult airway. It uses fiberoptic technology and mirrors to look around the nook and corners of larynx.

Advantages of Bullard laryngoscope:

1. It is very useful during difficult intubation
2. Since it is designed to be inserted with the patient's head and neck in neutral position it can be used safely in patients with unstable cervical spine
3. It can be used in patients with mouth opening of just 6 mm
4. It can also be used for nasal intubation procedures
5. It can also be safely used in paediatric population also since it is available in adult and pediatric sizes

Situations tailor made for the use of Bullard laryngoscope include:

1. Patients with anteriorly placed larynx
2. Patients with unstable cervical spine fracture
3. Patients with upper body burns / trauma
4. Patients with temporomandibular joint immobility
5. Patients with micrognathia

Bullard laryngoscope is desgined in such a way that its blade is anatomically curved. At the proximal end an eye piece is provided. It is also provided with a fibreoptic power source attachments. It has two ports i.e. One for oxygenation / instilling medicines / suctioning and the other one for attachment of endotracheal tube stylet. Illumination is provided by fiberoptic light source.

The choice of the size of Bullard scope (adult / pediatric) is made taking into account the height of the patient and the minimal size of endotracheal tube that can be fitted into the stylet.

If the patient is 5 feet and less – pediatric size is preferred

If the patient is more than 5 feet but less than 6 – adult size preferred

If the patient is more than 6 feet tall – adult size with tip extender is used

Procedure:

1. If adult Bullard laryngoscope is used the tip / blade extender is securely snapped into the laryngoscope blade.
2. Select appropriately sized endotracheal tube. The endotracheal tube connector is removed temporarily and lubricant is applied over it.
3. The stylet is inserted into the endotracheal tube until it protrudes out of the endotracheal tube opening
4. When looking through the optical eyepiece only the stylet should be seen and not the tip of the endotracheal tube
5. Lubricant should also be applied to the Bullard blade also to facilitate easy insertion. Care should be taken to use only water based lubricants
6. Attach fiberoptic light source to the laryngoscope

Oral intubation:

1. Induction drugs are adminsitered to the patient as for regular intubation
2. Patient should be in neutral position
3. Place yourself as if you are performing direct laryngoscopy, the axis of the scope should be parallel to patient's axis
4. The scope is introduced between the teeth into the pharynx and is inserted as close to the midline as possible. The endotracheal tube should be held firmly in the nook of Bullard's laryngoscope while the whole assembly is being advanced.
5. When epiglottis is visualized, the handle of the Bullard laryngoscope is elevated straight up, the tip of the laryngoscope could be then seen retracting the epiglottis out of the way facilitating direct visualization of laryngeal inlet
6. The endotracheal tube is advanced over the stylet, and under direct vision is pushed into the trachea between the relaxed vocal cords
7. The stylet is detached and the scope is gently removed after ascertaining that the endotracheal tube is in place
   
   
   
   
   
   
   
   

Laryngeal mask airway

Laryngeal mask was developed in 1980's, and recently is being used extensively in emergency medicine. It affords excellent ventilation without going through the normal intubation process and visualization of laryngeal inlet. It should be considered as a supraglottic airway management device. It can be introduced even by an emergency technician with training during emergency situations. Visualization of glottis is not essential for introduction of laryngeal mask airway.
Laryngeal mask was first developed by a British Anesthesiologist by name Archie Brain in 1980. Brain considered laryngeal mask airway as a physical junction between artificial and anatomic airway. According to Brain the major advantages of Laryngeal mask airway are:

1. It reduced dead space
2. Allowed normal functioning of protective reflex
3. It was highly reliable than face mask ventilation
4. It is really helpful in managing difficult airway
5. It is very useful during failed endotracheal tube intubation when the abdomen is full of inflated air. In these patients the danger of aspiration is very real. Insertion of laryngeal mask airway will not only secure the airway in these patients but also prevent aspiration of stomach contents.
6. It can be introduced even without paralyzing the patient



Development of laryngeal mask:

Brain designed laryngeal mask after careful study of plaster casts of cadaver airway. He also conceived that by inflating an elliptical cuff at the level of hypopharynx an airtight seal could be achieved. This method required reliable avoidance of down-folding of epiglottis within the mask orifice during insertion.
Laryngeal mask became commercially available in Britain in 1988, and US adopted it since 1992.

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Endoscopic cordectomy

Introduction:

Vocal cord malignancies can be identified at a very early stage because the primary symptom hoarseness of voice prompts the patient to seek medical attention during the early stages of lesion. With the increasing awareness of glottic cancers patients even seek attention during the carcinoma in situ stage itself. Early identification of the problem will help us to resort to conservative surgical procedures with curative intent. Accuracy of diagnosis is further enhanced by the common availability of video laryngoscopes even in the out patient settings commonly. In fact video laryngoscopy has become an out patient procedure, and it picks up vocal cord lesions at a very early stage itself.

Aims of endoscopic cordectomy:

1. Eradication of malignant process
2. Preservation of natural function
3. Can be used to stage the lesion

Advantages of endoscopic cordectomy:

1. Easily performed procedure
2. Relatively inexpensive
3. Preserves voice functions

Indications for endoscopic cordectomy:

1. T1 glottic carcinomas
2. Carcinoma in situ with mobile cord where irradiation is contraindicated

Contraindications:

1. Preoperative stroboscopy will help to rule out deeper tumor extension which is a contraindication for this procedure.
2. Patients with excessive tumor burden are not ideal candidates for endoscopic resection.
3. Patients with cervical spine degenerative disorders
4. Patients with poor mouth opening / retrognathia
5. Patients with short neck because visualisation of larynx is poor

Positioning of the patient:

Cordectomy / vocal cord stripping is performed ideally under general anesthesia. Patient is placed in supine position with head in 'flexion – flexion' position and intubated with laser safe endotracheal tube. Patient is then shifted to 'flexion – extension' position with cervical flexion and atlanto occipital extension. This position known as Boyce position helps in better visualisation of the anterior commissure area. A Klein Sausser suspension laryngoscope is used to visualize the laryngeal inlet and vocal cords. It is fixed in position with a chest piece. This really frees up both the hands of the surgeon. The entire tumor should be visible through the laryngoscope. Either a microscope or an endscope can be used to visualise the tumor.

Subepithelial injection of saline epinephrine solution using a Brunig's syringe or a butter fly needle will help to determine whether the lesion has spread beyond the lamina propria into the deeper structures like the vocal ligament or thyroarytenoid muscle. In addition to its diagnostic utility this fluid infiltration also serves as a potential heat sink if laser is used. It protects the deeper layers from laser burns.

In patients with carcinoma in situ it is sufficient if only the outer epithelial layer alone is removed and the plane of dissection is confined superficial to the lamina propria. Care should be taken not to expose the vocal ligament as it would entail damage to the gelatinous lamina propria. An intact lamina propria is a must for satisfactory voice production.

If pre op CT scan / stroboscopy reveals deeper invasion of tumor then resection should begin with vestibulectomy. Vestibule is vascular hence laser resection will help in minimizing bleeding. Affected vocal cord should also be removed. This is called classic cordectomy procedure.

Surgery in the anterior commissure area is always fraught with the danger of web formation due to exuberant granulation tissue. This can be avoided by stenting that area or applying mitomycin over the area. Application of mitomycin serves dual purpose, not only it is an anti cancer drug it also reduces the degree of fibrosis.

Figure showing growth vocal cord

Blow out fracture of orbit recent management trends

Blow out fracture of orbit is defined as fracture of one or more of its internal walls. This injury is typically caused by blunt trauma to orbit. In pure terms this definition does not involve the orbital rim. If fracture of orbital rim is associated with fractures of one or more of its internal walls then the term complex blow out fracture is used. Even though there is nothing complex about it, this term is used to stress the importance of non involvement of orbital rim in blow out fracture. Blow out fracture is actually a protective mechanism which ensures that sudden build up of intraocular pressure which could be detrimental to vision does not occur following frontal injury to orbit.



History: Blow out fracture of orbit was first described by Lang in early 1900's. The exact description of the fracture and the terminology (blow out fracture) was first coined by Converse and Smith. It was infact Smith who first described inferior rectus entrapment in between the fractured fragments, causing decreased ocular mobility.

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Infantile hemangioma - Role of Propranolol in its management

Introduction
Hemangiomas are common in children. It is seen in 1 in 10 of all children. About 50% of all hemangiomas in children are located in the head and neck area. Majority of them are single lesions which are inconspicuous at birth but undergoes rapid growth throughout the first year of life. Studies have also demonstrated that infantile hemanigomas are more common in premature infants. This has been attributed to the fact that mothers with premature uterine contractions receive tocolytics which are potential vasodilators.

Theories of infantile hemangioma:

1.Infantile hemangiomas have been postulated to originate from placenta – Studies have shown that endothelial cells constituting infantile hemangiomas resemble placental vessels
2.Mutation of endothelial cells
3.Environmental factors have been postulated to stimulate growth of these infantile hemangiomas

Regulators of hemangioma growth:

The topic of regulators involved in the growth and involution of infantile hemangiomas is still in infancy. Histologically infantile hemangiomas is composed of a mixture of clonal endothelial cells, pericytes, dendritic cells and mast cells.

Hemangiomas usually appears within the first few weeks of birth, undergoes rapid increase in size as the infant grows. The increase in size of infantile hemangiomas is much more rapid than that of infant's growth curve. This active proliferative phase is characterized histologically by plump endothelial cells showing evidence of frequent mitosis, increased number of mast cells and multilaminated basement membranes. Studies have demonstrated the involvement of two angiogenetic factors during this phase, they are basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF). This phase of active proliferation is followed by a phase of spontaenous slow involution (possibly due to apoptosis). This phase is characterized histologically by the presence of flat inactive normal looking endothelial cells in a matrix of fibrofatty tissue.

Treatment modalities:

1.Oral steroids
2.Systemic steroids
3.Cyclophosphamide
Among the above three treatment modalities systemic steroids offer the best results, of course with its attendant complications. Intralesional steroid injections have caused significant reduction in the size of these masses.

Use of Propranolol in the management of infantile hemagiomas was noticed by accident when a few children who underwent treatment for their cardiopulmonary conditions with propranolol showed significant reduction in the size of the hemagiomatous lesions. This led to a flurry of activity in the medical world. Propranolol was discovered by Sir James Black. It is a non selective beta blocker which revolutionized cardiac and hypertension management for a long time.


Therapeutic effects of propranolol in hemangioma:

1.Vasoconstriction – The ability of this drug to cause constriction of blood vessels supplying hemangioma tissue will cause significant reduction in its size. The hemangioma also undergoes significant softening in response to propranolol
2.Down regulation of angiogenetic factors like bFGF and VEGF
3.Upregulation of apoptosis of capillary endothelial cells


Dosage:

Propranolol should be administered during the proliferative phase of infantile hemangiomas in doses of 2-3 mg /kg /day divided into 2-4 doses.

Precaution:

The drug should not be discontinued abruptly and should be done in a tapered manner (during the period of 2-3 weeks) to prevent rapid increase in the size of the lesion.

Role of intraoperative imaging in endoscopic skull base surgery

Introduction:
Advances in nasal endoscopic surgery have prompted the surgeon to explore hither to unexplored vistas, like skull base surgery. It has been proved that endoscopic skull base surgery has helped in the reduction of morbidity and mortality of classical craniofacial approaches. Technologically superior endoscopes with wide field of vision, better illumination, camera and monitors have improved the success rate of these surgical procedures. These rigid endoscopes despite their obvious advantages provides only a 2 dimensional view of a complex 3 dimensional space. Image guided surgery was popularized in order to provide a certain degree of 3 dimensional view. Image guided surgery is heavily dependent on preoperative image data collection, resulting in a scenario of non visualization of the anatomic manipulation caused by the surgical procedure. This is where intraop imaging score over conventional image guided surgery because of its real time imaging ability. The operating surgeon will be virtually seeing the imaging of his surgical procedure.

Advantages of intraop imaging:

1.Provides real time images of the surgical field
2.These images can be fed into the image guidance system for better visualization of the surgical field. In other words it gives real time updates for image guided surgery.
3.Intra op imaging may help in performing extensive skull base surgeries using an endoscope.
4.It may be useful in managing complex craniofacial fractures


Equipment specification for intrao op imaging:

1.Equipment for image acquisition
2.Equipment for transferring the acquired image
3.Equipement for viewing and manipulation of acquired images
4.Software necessary to upload these real time images to the navigation system
5.A computer workstation to make all these things possible

Intra op imaging equipment should ideally be:

1.Portable
2.Capable of rapid image acquisition
3.Compatible with already commercially available image guidance systems
4.CT scanner / MRI scanner can be used for intra op imaging. CT scanner is preferrable because of its rapid scanning time, and excellent bone details which it provides.

Role of Cone Beam CT in intra op imaging:

This is slowly replacing conventional in office x-ray machines. It is very useful for rapid diagnosis of sino nasal and otological disorders. This CT machine permits imaging of the structure in question within single rotation. It uses the technique of volumetric tomography. Other major advantages of this imaging modality is reduced time of scanning and reduced exposure of the patient to harmful effects of irradiation. It is also comparatively less expensive than MRI scanners. These devices are highly portable and can be effortlessly wheeled into the operating room.

Image showing portable CT scanner

Three dimensional fluroscopy:

This is the other popular method of intra op imaging. It is highly portable and maneuverable. Patient is placed between the fluroscope and image intensifier. The image acquired is viewed on a portable workstation monitor. Softwares are available for converting the 2 dimensional image data acquired to 3 dimensional ones.

It should always be borne in mind that intra op imaging at the most provides complimentary information to the endoscopic portion of the surgical procedure.

Limitations of intra op imaging:

Are nothing but limitations of Cone Beam CT scanning. Due to technological limitations there is some loss in the quality of soft tissue imaging. Infact fluid / blood within the sinus cavity may be confused with that of residual mass / polyp. Hence intra op imaging should always be interpreted in conjuction with the endoscopic vision.

Sonotubometry and its role in assessing functional integrity of eustachean tube

Introduction:
Sonotubometry is based on the principle that sound when applied to the nasopharyngeal ostium of eustachean tube will be conducted through the eustachean tube into the middle ear when it opens. This concept was first conceived durning the 19th century. It has undergone lot of changes like introduction of better microphones. Politzer should be credited for the introduction of sonotubometry for analysis of eustachean tube function.

Principle:
In principle sonotubometry records changes in sound pressure level in the external auditory meatus when a constant sound source is applied to the nostril. In theory the eustachean tube opening will cause an increase in the sound pressure level of middle ear cavity causing a retrograde conduction of sound from the middle ear to the external canal which is recorded by a sensitive recording device. For this to occur the eustachean tube should open and close normally. By just recording the sound which is transmitted from the nose to the external canal via the eustachean tube it is possible to assess the functional integrity of the eustachean tube.

Diagram showing the placement of microphone in the external canal to record the transmitted sounds.

Advantages of sonotubometry:

1. 
   
   The whole procedure is performed under physiological conditions
2. 
   
   Static pressure is not applied over the external auditory canal
3. 
   
   The whole procedure is independent of the status of ear drum

Pitfalls of sonotubometry device:

1. 
   
   Leakage of sound from the nostrils and external auditory meatus
2. 
   
   Identifying the optimal frequency of test sound that should be used
3. 
   
   Results got corrupted due to the physiological noise of swallowing

These pitfalls were overcome by using inflatable nasal seals that would prevent leakage of sound from the nose and the use of pneumatic valve on the meatal microphone. This pneumatic valve would ensure that the external canal is sealed properly and there is no leakage of sound from it.

Regarding the frequency of test sound that should be used it has been demonstrated that frequencies between 6-8 kHz usually produced the best results. It has also been determined that frequencies of 5 kHz usually could be mistaken to that of physiological noises produced due to the act of swallowing.

Procedure:

The test is usually performed by placing a pneumatic microphone inside the external canal and a nasal sound probe which could generate sound at frequencies ranging from 6-8 kHz. Patient is asked to take about 20ml of liquid and hold it inside the oral cavity. When the sound is projected via nasal probe the patient is asked to swallow the liquid. This act of swallowing will open the normally functioning eustachean tube and is considered to be normal if the sound recorded at the external auditory canal reaches the level of 4dB sound pressure level. The duration of the eustachean tube opening can be calculated as the time difference between the onset of increase in the amplitude of sound and the return to its baseline.

Figure showing the sonotubometric curve. SPL reaches the peak level at the external canal 16 dB at 500 milliseconds. The base of the triangle formed by the curve is the time which eustachean tube is kept open. By looking at this curve eustachean tube functional abnormalities can be identified.

 

 

 

Taste disturbances following tonsillectomy

Introduction:
Tonsillectomy is a commonly performed surgical procedures these days. Even though it has its
own set of complications, disturbance in taste following surgery should be considered rare.
This article tries to dwell into the possible causes of taste disturbance following tonsillectomy.

Tonsillectomy is a commonly performed surgery these days. It is a reasonable safe surgical procedure
of course with its own set of complications. Certain complications like taste disturbance following tonsillectomy
is very rare. Seiichi Tomofuji et all managed to study the incidence of taste disturbance following tonsillectomy.
They devised a questionnaire to be answered by all tonsillectomy patients as given below:

1. Do you have taste disturbance after surgery ? (yes / no)

2. If the answer is yes what taste is blunted ? (sweet, salt, sour, bitter, umami, and all)

3. Do you feel any change in taste after surgery ? (yes / No)

4. If yes what change you feel ?

5. Do you feel thirsty ? (yes / no)

6. Are you able to eat ?

Based on this questionnaire they came to the conclusion that 1% of all tonsillectomy patients
had some disturbance in taste.

Causes of taste disturbances following tonsillectomy:

1. Injury to the lingual branch of glossopharyngeal nerve when the inferior pole of tonsil is snared

2. Due to pressure of mouth gag on the tongue

3. Zinc deficiency due to poor intake after surgery

4. Possible side effects of post op medicines (certain drugs chelate zinc antibiotics and analgesics)


Phantom taste should always be taken into consideration if lingual branch of glossopharyngeal nerve is
damaged on one side only.

Taste disorders include:

a. Hypogeusia

b. Ageusia

c. Dysgeusia

d. Phantogeusia

Patients usually ignore quantitative taste disorders. It is only the qualitative taste disorder like
persistent bitter / metallic taste that troubles a patient.

Postoperative zinc supplements in these patients may be of help. This is actually the consensus of opinion.

Anosmia in elderly

Introduction: Anosmia in geriatric age group is really common. Statistically speaking about 15% of geriatric population are anosmic. Anosmia in geriatric age group has disastrous consequences, including safety hazard. It affects the food preferences and nutritional status of the already compromised population. The absolute odor sensitivity as well as sensitivity to suprathrehold odors decreases in aging population. Loss of smell sensation could be a component of degenerative disorders like Alzeimer's disease and Parkinson's disease which commonly affect elderly age group.
Anosmia in elderly could very well be caused by pathologies involving either the transport of odoriferous molecules to the olfactory cleft or central processing mechanisms.

Applied anatomy & Physiology of smell:
Odors usually reach the olfactory epithelium present in the olfactory cleft orthonasally (anteriorly) via the nose and retronasally via the oropharynx. This retronasal pathway is essential for appreciating flavor of food consumed. In animals this pathway is essential to maintain the vital sense of smell even while feeding since it is very important for their survival. Odorants are appreciated when these molecules bind to the olfactory epithelium found in the roof of the nasal cavity. The most important feature of these olfactory receptor cells is the presence of non motile cilia which are the primary receptors of olfaction. These cilia are endowed with a large number of olfactory receptor proteins to which the odoriferous molecules bind. When these odoriferous molecules bind to the olfactory epithelium the G protein and cyclic AMP pathway is activated causing depolarisation of the olfactory receptor. The signal from the depolarized receptors are carried by the olfactory fibers to the primary olfactory cortex present in the uncus. The function of these receptors are dependent on the composition of mucous blanket which covers them. This mucous blanket is secreted by Bowman's glands and sustentecular cells. The quantity and quality of this mucosal blanket drastically changes in older age group blunting their ability to smell. Since the cilia over olfactory epithelium are nonmotile, the mucosal blanket clearance depends on the normal ciliary motility of the nasal epithelium.

The quality of the mucous blanket over the olfactory epithelium changes

1.During upper respiratory tract infection
2.Cigarette smoking
3.Inhalation of toxic substances
4.Old age

Pattern of airflow in to the nasal cavity plays an important role in olfaction. Studies have shown that major air flow occurs through the floor of the nose, next comes through the middle meatus. Only 10% of the inspired air traverses through the roof of the nasal cavity (olfactory area). It is this superiorly directed air flow that determines the acuity of olfaction. In elderly individuals due to atherosclerotic changes of submucosal vessels the turbinates dont congest and decongest automatically, causing the air flow through the nasal cavity to be laminar in nature. Laminar air flow always occurs through the floor of the nasal cavity depriving the olfactory area's exposure to the inspired air. Hence elderly individuals resort to sniffing in order to perceive smell. Alar muscles of the nose must be acting normally in these persons for eddy currents to develop in the inspired air. Eddy currents ensure atleast a portion of the inspired air travels through the roof of the nasal cavity. In elderly individuals the alar muscles are weak and periodical sniffing acts leaves them really tired and drowned hence they avoid making this consious effort to perceive smell.

The olfactory epithelial layer is endowed with the presence of progenitor cells. These cells on maturation can progressively replace degenerated olfactory receptor cells. The number of these progenitor cells undergoes progressive reduction as the patient ages. Hence the regenerative ability of olfactory epithelium is highly restricted in geriatric age group compounding the problem of anosmia.

Olfactory receptor cells: These are bipolar neurons which are not only constantly exposed to odoriferous molecules but also to the insults heaped upon by viral infections, inflammations, and inhaled toxins. They undergo regular death by a process known as apoptosis. Their population is continuously replaced by the maturing progenitor cell pool. In nasal and sinus disorders the level of enzyme capsase 3 increases to alarming levels. This enzyme stimulates apoptosis (programmed cell death) of the olfactory receptors.
Importance of mucosal blanket over olfactory cleft in maintaining the function of smell:

1.The odoriferous molecules dissolves in the mucosal blanket before they are exposed to the olfactory epithelium
2.The mucosal blanket also clears the odoriferous molecules after they have stimulated the olfactory epithelium
3.The water content of the mucosal blanket plays an important role in maintaining the normal olfactory function. In patients of geriatric age group the hydration of the mucosal blanket is poor and hence there is a diminition in the olfactory function.
4.Exposure to cigarette smoke delays clearance of the mucosal blanket causing diminition of sensation of smell
5.Exposure to heavy metals like manganese (prolonged) causes alteration in the metabolism of the mucosal blanket causing subtle changes in its composition leading on to blunting of sensation of smell. This is the third common cause of olfactory problems in elderly.

Olfactory epithelial changes that occur due to aging:

As the individual grows older the olfactory epithelium gets progressively replaced by respiratory epithelium causing a diminition in the sensation of smell. Studies have shown that significant amount of olfactory epithelium gets replaced by respiratory epithelium by the time a person reaches the age of 70.

Damage to olfactory bulb and neuronal olfactory pathways due to degenerative neurogenic disorders are common in old age group. This is one important cause for blunting of sensation of olfaction in a patient above the age of 80. Alzeimer's disease is the most common degenerative disorder affecting this group of patients. It not only causes dementia in this age group, but also blunts their olfaction. Diminition of olfactory sensation is seen in early stages of Alzeimer's disease.

Appreciation of flavor of food:
This is dependent on retronasal olfaction. This is commonly affected in elderly individuals who use palate covering dentures. This is one of the common cause of loss of flavor of food stuffs seen in geriatric patients. In addition healthy oral cavity is a must for perception of flavors. Dry oral cavity commonly seen in elderly also cause loss of perception of flavor of food.