ACOMS Flashcards
The most common soft tissue fillers used in minimally invasive facial cosmetic surgery are:
A. Hyaluronic Acid (HA)
B. Calcium Hydroxyapatite (CaHA)
C. Poly-L-Lactic Acid (PLLA)
D. Collagen
Answer: A
Minimally invasive facial cosmetic surgery procedures have seen an increase in numbers over the past 10 years. The American Society of Plastic Surgeons reported that the number of minimally invasive procedures increased 4% from 2013 to 2014. The most common soft tissue fillers used are Hyaluronic Acid (HA) (Answer A). Calcium Hydroxyapatite (CaHA) (Answer B) is a resorbable filler that has gained popularity for its long-term duration of up to 2 years. PLLA’s (Answer C) duration of augmentation is up to 3 years. Collagen (Answer D) was developed in the 1970s and was approved for use by the FDA in 1981. Collagen was regarded as the gold standard since it was relatively safe to use, was temporary, and did not elicit a foreign body reaction. As of today, these products are no longer available in the United States.
References:
American Society of Plastic Surgeons: 2014 Plastic Surgery Statistics Report. Available at: http://www.plasticsurgery.org/ Documents/news-resources/statistics/2014-statistics/plasticsurgery-statsitics-full-report.pdf.
A traditional cleft lip develops when there is lack of fusion between which structures?
A. The medial nasal process and the lateral nasal process
B. The lateral nasal process and the maxillary process
C. The medial nasal process and the maxillary process
D. The palatal shelf and the maxillary process
Correct answer: C
The traditional cleft lip develops when there is partial or complete failure of the medial nasal process and the maxillary process to fuse. A cleft palate forms when there is partial or complete failure of the bilateral palatal shelves to fuse.
Reference:
Posnick, JC. Chapter 3: Definition and Prevalence of Dentofacial Deformities. In: Posnick, JC. Orthognathic Surgery: Principles & Practice. Vol I. Saunders, St. Louis.
The temporoparietal fascial flap has vascular supply from the superficial temporal artery and its branch of
A. Superior temporal artery
B. Anterior deep temporal artery
C. Middle temporal artery
D. Posterior deep temporal artery
Correct Answer :C
This question clarifies temporoparietal fascial flap vs temporalis musculo- fascial flap vascular anatomy. The temporoparietal fascial flap is a versatile pliable highly vascular flap based on the branches of the superficial temporal artery and vein. More precisely it forms the continuation of the superficial musculoaponeurotic system( SMAS).
The superficial temporal artery and its anterior, posterior and middle temporal arteries contribute to the temporoparietal fascia and to the deeper temporalis muscle fascia vascular regions. So choice c is correct. Choice b & d are branches of the second part of the maxillary artery. The deep temporal communicating branch of the superficial temporal artery anastomoses medial to the temporalis fascia -muscle with the anterior and posterior temporal branches (b & d) of the maxillary artery. Choice a is incorrect terminology of the temporal termination of the external carotid artery.
The clinical relevance is that precise knowledge of this anatomy is essential in elevating pedicled or free flaps in this region. Multiple flaps with osteomusculofascial components and bilobed flaps can be fabricated.
Which incision provides the best access to the medial orbital wall when managing an orbital blow out fracture?
A. Transconjunctival
B.Subciliary
C.Subtarsal
D.Infraorbital
Four incisions have been described to approach the orbital rim and floor. The transconjunctival has been popularized at this time. Three transcutaneous incisions have also been described: subciliary, subtarsal and infraorbital. The infraorbital incision is least esthetic and is generally not employed today. Both the subsiliary and subtarsal approaches both provide excellent access to the lateral orbital rim and wall, inferior orbital rim and floor and the frontal process of the maxilla in management of naso-orbito-ethmoidal fractures. Of these incisions the subciliary is technically more challenging and associated with higher incidence of complications. The transconjunctival incision avoids a cutaneous scar but potentially may limit access to the lateral orbital wall without making a latral canthotomy and cantholysis. However, the incision does facilitate improved access to the medical orbital wall compared to the other incisions
Antibiotic failure can be defined as:
A.development of hives and body rash
B.nausea and vomiting immediately following an antibiotic dose
C.lack of clinical improvement despite adequate drainage
D.extensive bacterial growth on culture samples following I&D
Antibiotic failure is defined as a lack of clinical improvement of the swelling, persistent fever and elevated white blood cell count 48 hrs following adequate surgical treatment to remove all potential sources of infection and establish drainage of all abscess sites when clinically appropriate antibiotics are also administered. In this clinical scenario a change in antibiotic treatment should be considered.
The development of hives and a body rash are indicative of an allergic reaction whereas nausea and vomiting indicates drug intolerance. It is common to have bacterial growth from I&D specimens even when the antibiotic is appropriate.
References
Flynn TR, Shanti RM, Levy M, et al. Severe odontogenic infections. Part 1: Prospective report. J Oral Maxillofac Surg 64:1093-1103, 2006.
Flynn TR. Use of antibiotics. In Laskin DM, Abubaker AO. Decision making in Oral and Maxillofacial Surgery. Quintessence Publishing Co, Hanover Park Ill, 2007
What is the diameter of the gas evacuation connector on all modern gas machines?
A. 15 mm.
B. 19 mm.
C. 22 mm.
D. 20 mm.
Answer: B
It is important to understand the rationale behind the standardization of connections on modern gas machines. These standards have evolved since the Z79 standard adopted by all manufacturers of gas machines since 1979. Prior to that time, each manufacturer had its own standard for breathing circuit fittings. This caused many errors in gas administration with accompanying potential patient compromise. Prior to these standards, it was necessary to use the manufacturers own hardware to get everything to fit together. Today all endotracheal connectors, regardless of size, are 15mm at the attachment end, all adult masks are 22 mm, and some pediatric masks are 15 mm. Breathing tubes are also 22 mm. This prevents misconnections. The scavenging connector has been designed to be 19 mm to prevent accidental connection to the breathing circuit with the potential for applying negative pressure to the breathing side of the circuit with the danger of causing negative pressure pulmonary edema. 19 mm is too large for 15 mm and two small for 22 mm.
Ulcerative colitis is characterized by:
A. transmural inflammation
B. intestinal fisulation.
C. skip lesions.
D. submocusal T cell infiltrates.
Correct answer: D
Rationale:
Ulcerative colitis is an autoimmune disorder which is generally limited to the rectum and colon. Lesions are composed of T cell inflammatory areas that are limited to the mucosa and submucosa of involved areas. The pathology in ulcerative colitis typically involves distortion of crypt architecture, inflammation of crypts (cryptitis), frank crypt abscesses, and hemorrhage or inflammatory cells in the lamina propria. Lesions are not transmural and therefore intestinal fistulation is not seen. Transmural inflammation, fistulation, and abrupt areas of involvement/normal mucosa are typical of Chrons disease, which can be evident all along the GI tract.
Which of the following is an advantage of a fixed implant supported prosthesis?
A. Requires less implants for support than a removable prosthesis
B. Shorter Implant fixtures can be used
C. Complications are easier to treat
D. Psychological (feels more like natural teeth)
Answer: D
Rationale:
The psychological advantage of a fixed prosthesis is that the patients often feel as if they are getting their own teeth restored. The fixed prostheses often last longer than removable overdentures because the attachments do not require replacement and the acrylic denture teeth wear faster than porcelain-metal teeth. Food entrapment is also more likely with a removable prosthesis. A fixed implant prosthesis will require at least as many fixtures as a removable prosthesis and often times will require more.
What type of graft transfers a portion of the donor site skin including the epidermis and some of the underlying dermis?
a. Full thickness skin graft
b. Composite graft
c. Split thickness skin graft
d. Pedicle graft
Answer: C
Rationale:
Split thickness skin grafts — Split thickness skin grafts (STSG), also called partial thickness grafts, transfer a portion of the donor site skin including the epidermis and some of the underlying dermis. This allows the donor site to heal from the epidermal elements left behind. STSG can be utilized as an intact sheet or expanded via a mechanical mesher device. Meshing of a graft increases the surface area that can be covered by a graft.
Composite graft - a transplantation that involves more than one type of tissue, such as skin and cartilage. The term may also refer to an artificial vessel graft, such as an aortic valve prosthesis used to replace the ascending aorta valve.
Full thickness skin grafts — Full thickness skin grafts (FTSG) harvest the entire layer of skin as the graft. Thus, no dermal or epidermal elements remain at the donor site, which must be closed by local advancement of the adjoining skin or by a secondary local flap. The process of revascularization takes longer for a full thickness graft than for a split thickness skin graft because of the increased thickness of the tissue, but final shrinkage is less than for a partial thickness skin graft.
Pedicle graft - utilize tissue in the vicinity of the defect without actually abutting the defect. An example of a regional flap is the forehead flap for nasal tip reconstruction, which is based on the supraorbital and supratrochlear vessels, and includes the glabellar and frontalis musculature.
What is the name of a rare tumor in adolescent males, demonstrates epistaxis, is locally invasive, has thin-walled vessels devoid of smooth muscle, exhibiting staghorn shapes, in a fibrous to myxoid stroma?
A. Sarcoma
B. Olfactory Neuroblastoma
C. Ameloblastoma
D. Juvenile nasopharyngeal angiofibromas
Answer: D
Rationale:
Juvenile nasopharyngeal angiofibromas — Juvenile nasopharyngeal angiofibromas (JNA) are rare tumors exclusively seen in adolescent males, presenting with epistaxis. The lesion is locally invasive but morphologically deceptively bland, showing thin-walled vessels, devoid of smooth muscle, often exhibiting staghorn shapes, and set in a fibrous to myxoid stroma. Local involvement of the nasal cavity and paranasal sinuses may be extensive, with occasional invasion of the skull base. Intraoperative bleeding may be marked and potentially life threatening. Preoperative measures to diminish blood loss, eg, tumor embolization, may be clinically useful.
Ameloblastoma — Ameloblastomas are rare tumors that arise in the jaw. Most are nonmetastasizing, although they are locally aggressive. Ameloblastomas commonly recur if not adequately resected. These tumors have been associated with the V600E mutation of BRAF and may respond to targeted intervention.
Sarcomas — sarcomas are rare, accounting for approximately 2 percent of all head and neck malignancies. Patients generally present with a palpable mass (especially in the neck), skin changes (especially on the scalp or face), or subsite-specific symptoms (eg, hoarseness with laryngeal primaries, dysphagia with oropharyngeal tumors, epistaxis, nasal obstruction, or cranial nerve deficits with skull base tumors).
Olfactory neuroblastoma — Olfactory neuroblastoma (ONB; esthesioneuroblastoma) is a rare tumor arising from the roof of the nasal cavity (cribriform plate) and paranasal sinuses. Nasal obstruction due to the presence of a mass is the most common symptom with olfactory neuroblastoma and is present in the majority of cases. Other manifestations of local disease include epistaxis, nasal discharge, and/or pain. When nasal symptoms are present, physical examination usually reveals a red-brown, polypoid mass located high in the nasal cavity.
The TMJ articular surface of the condyle is covered with which type of cartilage?
A. Hyaline
B. Fibrocartilage
C. Elastic
D. Type II collageous
Answer: B
Rationale:
The TMJ articular surface of the condyle is covered with fibrocartilage (Answer B). The TMJ is different in composition from other joints in the body. In other synovial joints, the articular surfaces are covered with hyaline cartilage (Answer A). One of the unique characteristics of fibrocartilage is that it contains both types I and II collagen, compared to hyaline cartilage, which only contains type II collagen. Additionally, fibrocartilage is better able to withstand sheer forces than hyaline cartilage. This makes it a superior material for enduring the large amount of occlusal load that is placed on the TMJ.
Elastic cartilage (Answer C), also known as yellow cartilage, is a type of cartilage present in the outer ear, Eustachian tube, and epiglottis. It contains elastic fiber networks and collagen fibers. Elastic cartilage is histologically similar to hyaline cartilage but contains elastic fibers lying in a solid matrix. These fibers give elastic cartilage great flexibility so it is able to withstand repeated bending. Type II collagen (Answer D) is the essential ingredient of hyaline cartilage.
The most common cause of post-operative lagophthalmos after an upper eyelid blepharoplasty is:
A. superficial ecchymosis.
B. wound dehiscence.
C. excessive fat removal.
D. excessive skin removal.
Answer: D
Rationale:
All four answers are potential post-operative complications of an upper eyelid blepharoplasty. However, the most common cause of post-operative lagophthalmos is excessive removal of upper eyelid skin (Answer D). Measurement and pre-operative planning are key factors to avoid excessive skin removal and overcorrection. Generally, the surgeon should leave 10 mm of skin under the brows above the upper lid crease incision in order to avoid lagophthalmos, and more if the lid crease height is less than 10 mm from the lid margin. Due to the inability to close the eyelid, intractable exposure keratitis can occur. Particular care must be taken in patients with extremely excessive skin, low-set brows, previous brow lift, or previous blepharoplasty. Management of excessive skin removal requires a full thickness skin graft. If the surgeon preserved the excised skin in moist gauze, this can be utilized up to one week post-operatively. Otherwise, retroauricular skin is often available and is a good option for eyelid skin.
Superficial ecchymosis (Answer A) and bruising will be experienced by every blepharoplasty patient. In order to minimize bruising, the patient should avoid using anticoagulant drugs, control his or her hypertension, and avoid post-operative trauma. Risk factors for postoperative wound dehiscence (Answer B) include infection and post-operative trauma. Minimizing wound dehiscence involves appropriate suture choice, suture placement, and avoiding post-operative trauma. Excess fat removal (Answer C) can lead to a hollowed-out appearance in the upper eyelid. This could be very upsetting to the patient who has always been heavy-lidded. Time will often soften an upper eyelid crease as the patient learns to relax his or her eyebrows which were chronically arched preoperatively due to dermatochalasis. As a corrective measure, filling in the hollowed areas can be achieved using fat injections, dermis fat grafts, or alloplastic injections.
Genial tubercle advancement for obstructive sleep apnea using a mortise and tenon technique:
A. eliminates the need for rigid fixation.
B. allows the osteotomy design to aid in stability
C. Involves labial osteotomy higher than the lingual osteotomy.
D. disallows advancement of the mylohyoid and digastrics muscles.
Correct answer: B.
Rationale:
The mortise and tenon technique for genial advancement involves making a labial monocortical bone cut on the symphysis with a hanging “tenon” in the area of the incisors that is connected to a bicortical osteotomy more posteriorly extending to the inferior border at the area of the first molars. The bicortical osteotomy is directed with a reciprocating saw through the lingual border at a level cephalad to the inferior border of the tenon, allowing the genial tubercles to be advanced with the osteotomized segment. This segment carries the attachments for the genioglossus, geniohyoid, anterior digastrics, and most of the mylohyoid muscles. A mortise in the inferior mobilized segment can then be made to allow the tenon (labial cortex) and the lingual cortex of the inferior segment to be lag screwed to each other, increasing stability. Lag screws allow rigidity of fixation, ensuring bony healing and decreasing relapse potential.
References:
Wolford LM, Bates JD. Surgical modification for the correction of chin deformities. Oral Surg Oral Med Oral Pathol 66: 279, 1988
Gooday R. Orthognathic Surgery for Obstructive Sleep Apnea. In: Fonseca et al (eds.): Oral and Maxillofacial Surgery, Vol III (2nd ed.) Saunders/Elsevier, St. Louis.2009 325-7
An orbital fracture with retrobulbar hematoma associated with an increased intraocular pressure and visual impairment:
A. can be surgically decompressed solely with a lateral canthotomy.
B. should be drained within 6 hours of onset of visual impairment.
C. may be the result of reduced perfusion in the central retinal artery.
D. is medically managed with steroids and/or carbonic anhydrase inhibitors.
Answer C
Rationale
Visual impairment associated with a retrobulbar hemtoma requires urgent intervention. It is secondary to increasing pressure in a combined space, which may: result in reduced perfusion of the retinal artery to the optic nerve; a direct compressive effect on the neurosensory structures; or diminished venous outflow. Clinical presentation may include a proptotic eye with a hard eyeball, a deficit in pupillary light reflex, a relative afferent papillary defect, impaired ocular motility and visual impairment. Decompression must be performed within 2 hours of onset of visual impairment to minimize the loss of vision. If the hematoma cannot be directly approached and evacuated, decompression consists of a lateral canthotomy with a inferior limb cantholysis releasing the lateral canthus ligament. A lateral canthotomy by itself is limited in reducing the intraorbital pressure. Medical manage consists of the administration of steroids, carbonic anhydrase inhibitors and or mannitol. Some surgeons combine steroids with surgical decompression but the benefit for this is not clear. Medical management by itself is inappropriate in a patient presenting with impaired vision.
References:
Voss JO, Hartwig S, Doll C, et al. The “tight orbit”: Incidence and management of the orbital compartment syndrome. Journal of Cranio-Maxillo-Facial Surgery 44:1008;2016
Ho TQ, Jupiter D, Tsai JH, et al. The incidence of ocular injuries in isolated orbital fractures. Annals of Plastic Surgery epub ahead of print
The most likely etiology for an injection nerve injury is:
A. neurotoxicity of the anesthetic agent
B. direct mechanical trauma to the nerve
C. perineural hematoma formation
D. perineural scar tissue formation
Answer: A
Rationale
Injection-related nerve injuries are rare events that are closely related to the type of anesthetic agent used. The more concentrated agents (%4 articaine, 4% prilocaine) are associated with a higher risk of neuropathy as compared to other less potent concentrations. This has been demonstrated in several population studies in the U.S. and abroad. Despite the low market share of the higher concentration local anesthetics, the incidence of injection-related neuropathy associated with these agents is significantly higher than the other preparations. This suggests a neurotoxic etiology for these types of injury. Mechanical injury from a very small caliber needle can and does occur but to a much lesser degree. The formation of a hematoma or perineural scar tissue can occur with either a mechanical or chemical injury.
References
Hillerup S, Jensen RH, et al. Trigeminal nerve injury associated with injection of local anesthetics: needle lesion or neurotoxicity? J Amer Dent Assoc 142(5):531-539, 2011
Garisto GA, Gaffen AS, et al. Occurrence of paresthesia after dental local anesthetic administration in the United States. J Amer Dental Assoc 141(7):836-844, 2010.
Anesthetic induction using the high sevoflurane concentration technique compared to the low concentration technique has a higher incidence of:
A. apnea.
B. laryngospasm.
C. cough.
D. tachycardia.
Answer A
Rationale
Two different sevoflurane inhalational techniques are described in the literature. A high sevoflurane concentration technique administers a sevoflurane concentration between 4% to 8%. Different breathing techniques have been described which vary from tidal volume to vital capacity breathing. A low sevoflurane concentration technique starts with a low initial concentration, which progressively increases in concentration as the patient breathes. The potential advantage associated with the high sevoflurane concentration is a more rapid anesthesia induction. The studies tend to show a more rapid anesthetic induction with the high sevoflurane concentration but the comparison of studies supporting this conclusion is low quality evidence because of the heterogeneity within the various studies. The concern with a higher concentration is an associated higher incidence of complications. The literature, however, did not find a higher incidence of cough, laryngospasm, breath holding, patient movement, salivation or bradycardia. The studies did suggest, although also with low quality evidence that there was a higher occurrence of apnea associated with the higher sevoflurane concentration.
Which of the following anticoagulants has a pharmacologic reversal agent currently available?
A. Apixaban (Eliquis)
B. Edoxaban (Savaysa)
C. Rivaroxaban (Xarelto)
D. Dabigatran (Pradaxa)
Answer: D
Rationale:
Anticoagulants are useful for thrombosis prevention in patients with a history of DVTs, PEs, occlusive CVAs, and in cases of atrial fibrillation. Formerly, warfarin (Coumadin) was the agent of choice in these situations. Warfarin inhibits the hepatic production of Vitamin K dependent coagulation factors, and has the disadvantages of having wide free plasma levels depending upon dietary intake, and having a long duration of effect. However, its clinical effect is easily measured with standard INR assays and is easily reversible with exogenous Vitamin K or fresh frozen plasma. Dabigatran is a direct thrombin (Factor II) inhibitor, and has been FDA approved for use to reduce the risk of thrombotic events in the above cited patient populations where no cardiac valve replacement has been done. Clinical effect is maximum 2 hours after oral administration and half life is 14 hours. The drug is poorly protein bound and easily dialyzed. A recently approved reversal agent for emergent use has been approved: Idarucizumab (Praxbind) which is a monoclonal antibody for dabigatran. Clinical effect of dabigatran can be indirectly assayed by thrombin time.Rivaroxaban (Xarelto), apixaban (eliquis) and edoxaban (Savaysa) are direct Factor Xa inhibitors. As of yet there are no reliable assays to judge their clinical effect, and there are no available reversal agents. Several investigational agents are being studied for Factor Xa reversal: Andexanet alfa (a Factor Xa analog with no coagulant activity but higher affinity for inhibitors than native Factor Xa); andciraparantag (a direct binding inhibitor.) Being highly protein bound, Factor Xa inhibitors are not easily removed via emergent dialysis. However, all of the new Factor II and Xa inhibitors have been found to have less bleeding risk globally than warfarin.
The most common complication associated with the zygoma implant is:
a. Late implant failure
b. Temporal space infection
c. Sinusitis
d. Paresthesia of the cheek
Answer: C
Rationale:
The use of a zygomatic implant has been a viable alternative to reconstruct the atrophic or resected maxilla. When indicated the use of these implants has several advantages including decreased treatment time, elimination of complex bone grafting, requirement of fewer conventional implant fixtures. These advantages are primarily due to the fact that the implant does not rely on the alveolar bone for support. The dense zygoma bone provides nearly all the support. One or 2 implants can be placed on each side. Prostheses in completly edentulous cases require additional conventional implants in the anterior maxillary alveolar bone for anterior support. In a recent systematic review of the complications and survival of 4,550 zygoma implants sinusitis was noted found to be the most common complication (2.4%) followed by soft tissue infection (2.0%), paresthesia (1.0%) and oroantral fistulas (0.4%). The 12 year cumulative survival rate was 95.21% where most of the failures were reported in the first 6 months.
References:
- Chrcanovic BR, Albrektsson T, Wennerberg A. Survival and complicatios of zygomatic implants: An updated systematic review. J. Oralmaxillofac Surg 74:1949-64, 2016
- Aparicio C, Ouazzani W, Garcia R, et al. A prospective clinical study on titanium implants in the zygomatic arch for prosthetic rehabilitation of the atrophic edntulous maxilla with a follow-up of 6 months to 5 years. Clin Implant Dent Relat Res 8:114, 2006
- Bedrossian E. Rehabilitation of the edentulous maxilla with the zygoma concept: A 7-year prospective study. Int J Oral Maxillofac Implants 25:1213, 2010
What term refers to the basic unit of structure of compact bone, comprising a haversian canal and its concentrically arranged lamellae?
a. Osteocyte
b. Volkmanns Canal
c. Canaliculi
d. Osteon
Answer: D
Rationale:
The osteon or haversian system is the fundamental functional unit of compact bone. Osteons are roughly cylindrical structures that are typically several millimeters long and around 0.2mm in diameter. They are present in many bones of most mammals and some bird, reptile, and amphibian species. Each osteon consists of concentric layers, or lamellae, of compact bone tissue that surround a central canal, the haversian canal. The haversian canal contains the bone’s blood supplies. The boundary of an osteon is the cement line. Some osteoblasts develop into osteocytes, each living within its own small space, or lacuna. Osteocytes make contact with the cytoplasmic processes of their counterparts via a network of small transverse canals, or canaliculi. Osteons are connected to each other and the periosteum by oblique channels called Volkmann’s canals or perforating canals.
References:
John P. Bilezikian, Gideon A. Rodan, and Lawrence G. Raisz (eds.), Principles of Bone Biology, 2nd ed. (2002)
What thyroid carcinoma causes elevated level of serum calcitonin and begins in the parafollicular cells (C cells) of the thyroid?
a. Papillary
b. Medullary
c. Anaplastic
d. Follicular
Answer: B
Rationale:
Papillary thyroid cancer: The most common form of thyroid cancer, papillary cancer arises from follicular cells, which produce and store thyroid hormones. Papillary thyroid cancer can occur at any age, but most often it affects people ages30-50.
Follicular thyroid cancer: Follicular cancer also arises from the follicular cells of the thyroid. It usually affects people older than age 50. Hurthle cell cancer is a rare and potentially more aggressive type of follicular thyroid cancer.
Medullary thyroid cancer: Medullary thyroid cancer begins in thyroid cells called C cells that produce the hormone calcitonin. Elevated levels of calcitonin in theblood can detect medullary thyroid cancer at a very early stage. Certain genetic syndromes increase the risk of medullary thyroid cancer, although this genetic link is uncommon.
Anaplastic thyroid cancer: Anaplastic thyroid cancer is a rare and rapidly growing cancer that is very difficult to treat. Anaplastic thyroid cancer typically occurs in adults age 60 or older.
Which of the following is considered a permanent soft tissue filler?
A. Hyaluronic acid (HA)
B. Calcium Hydroxylapatite
C. Polymethylmethacrylate (PMMA) microspheres
D. Poly-L-lactic acid (PLLA)
Answer: C
Rationale:
Soft tissue fillers have become popular in facial cosmetic surgery. The FDA classifies facial soft tissue fillers into 2 categories. These are:
- Absorbable (temporary) materials
- Non-absorbable (permanent) materials
Absorbable and temporary fillers include collagen and hyaluronic acid (HA) (Answer A). The effects of collagen fillers generally last for 3-4 months. They are the shortest lasting soft tissue fillers. HA fillers usually last 6-12 months. HA with dextranomer beads, poly-L-lactic acid (PLLA) (Answer D), and calcium hydroxylapatite (Answer B) are included in the absorbable, long-term category. Calcium hydroxylapatite lasts between 18-24 months. PLLA usually lasts up to 2 years. Commonly used permanent options include silicone preparations, polymethylmethacrylate (PMMA) microspheres (Answer C), polyacrylamide hydrogels (PAHG), and polyalkylimide gels. PMMA is a non-degradable, biocompatible polymer.
When using the reciprocating saw posterior to the antelingula during a mandibular intraoral vertical ramus osteotomy, brisk hemorrhage is encountered, most likely originating from the:
A. First portion of the maxillary artery
B. Retromandibular vein
C. Pterygoid venus plexus
D. Ascending pharyngeal artery
Correct answer: A
Rationale:
The first portion of the maxillary atery arises from the external carotid artery within the substance of the parotid gland. This runs forward medial to the upper mandibular vertical ramus on its medial aspect and is divided into three parts:
1st part: runs lateral to the sphenomandibular ligament up to the posterior border of the lateral pterygoid muscle. This gives off five branch arteries: deep auricular, anterior tympanic, middle meningeal, accessory meningeal, inferior alveolar. The first portion lies medial to the mandible at or above the antilingular prominence (on the lateral surface of the ramus opposite to the lingual and mandibular foramen on the medial surface.)
2nd part: From the posterior/inferior border of the lateral pterygoid muscle to the anterior border of the temporallis insertion. The second portion’s terminal arterial branches are: masseteric, pterygoid (medial and lateral), anterior and posterior deep temporal, and buccal.
3rd part: Running anterior and medial, entering the pterygoid fissure. The final arterial branches include: sphenopalatine, descending palatine, infraorbital (with middle and anterior superior alveolar branches), posterior superior alveolar, pterygoid canal, pharyngeal
At the area just posterior to the antilingula (approximately 7 mm anterior to the posterior mandibular border) is the zone of transition between the first and second portions of the maxillary artery (just as it contacts the inferior head of the lateral pterygoid muscle.) In this case, bleeding is best controlled by completing the osteotomy, bringing the proximal segment laterally and the proximal segment anteriorly and under direct visualization control the arterial bleed. If unable to do so, the surgeon must be ready to arrange hemostasis by intraarterial embolization or by an external carotid artery ligation.
If correct positioning of the oscillating blade is made and the periosteal envelope is intact, the retromandibular vein should not be in the field of osteotomy. The same should be true for the pterygoid venus plexus ( which is in the infratemporal fossa, well superior to the surgical field) and the ascending pharyngeal artery, which has an origin on the external carotid near the carotid bifurcation and runs well medial to the surgical field.
Antero-posterior compared to laterally directed impact forces on the craniofacial skeleton result in more:
A. subdural hematomas.
B. diffuse axonal injuries.
C. severe traumatic brain injuries (TBI)
D. concussive injuries secondary to the rotational forces.
Answer: A
Rationale:
Fractures of the craniofacial skeleton can have associated neurologic injuries. Clinical examination and imaging are integral to assessing the patient. Understanding the mechanism of injury may also provide some insight into the patient’s potential neurologic deficit.
The midface craniofacial skeletal structure consists of the paranasal sinuses, nasal cavity and orbits, which act as a “crumple zone”. This structure protects the intracranial contents and dissipates forces. Antero-posterior directed injuries were associated with a higher incidence of subdural hemtamas. Directional injuries that are more lateral result in a greater torsional or rotational force on the intracranial contents resulting in more severe injuries. These forces result in a higher incidence of traumatic brain injury (TBI), and parenchymal injuries. Diffuse axonal injuries are associated with rotational forces. Rotational injuries have been associated with a higher incidence of concussions.
The more severe injuries are associated with lower Glascow Coma Score (GCS). In a recent study the median GCS was 14 and 5 for antero-posterior impact and lateral directed impact, respectively. A GCS with a score of 8 or less is classified as being in a coma. Protocol in managing these patients dictates intubation to protect the airway and maintain oxygenation to minimize further neurologic deficit
Nystagmus is a common side effect associated with which of the following medications?
a. Meperidine
b. Midazolam
c. Ketamine
d. Propofol
ANSWER: C
Rationale:
Nystagmus is an involuntary and rapid movement of the eye. Nystagmus may occur after the administration of many agents, but of the anesthetic agents it is a typical reaction with ketamine. Ketamine is a dissociative anesthetic that produces a unique anesthetic state. Other side effects associated with ketamine include diplopia, PONV and emergence delirium. All of these are dose related. Resolution of the nystagmus in a patient who has received ketamine is a good indication of their anesthetic recovery and ability to be discharged.
Classification of obesity for pediatric patients includes:
calculation of body mass index (BMI) which is different from adult BMI calculation.
use of standardized tables based on age and race.
employment of gender-based calculators.
is the same as is used for adults.
Answer: C
Rationale:
Classification of obesity is important not only for general health maintenance but for safe application of anesthesia and drug dosing. Pediatric obesity calculation is based on aged based nomograms. There are separate nomograms for boys and girls. BMI calculations are commonly done with height and weight charts although more complex calculators are available. BMI calculations for adults and pediatric patients over the age of 2 are identical, but weigh classification of adult and pediatric patients is different.
For pediatric patients, using the gender and age appropriate nomogram, the following CDC classifications have been made:
Underweight: BMI < 5th percentile
Normal weight: BMI between 5th and 85th percentile
Overweight: BMI between 85th and 95th percentile
Obese: BMI > 95th percentile
Severely obese: BMI > 120% of 95th percentile value, or BMI > 35 (whichever is lower)
The prevalence of obesity and severe obesity is increasing in the American pediatric population, and is greater in Native American, African American, and low income communities. Early obesity has been linked to early onset diabetes, infertility, and vascular diseases.
Excessive crestal bone loss that is noted within 6 months of loading an implant is most likely due to:
improper emergence profile
excessive occlusal loading
bacterial infection
reaction to cement
Answer: B
Rationale:
Early crestal bone loss or saucerization that exceeds beyond the thread level of an implant is typically due to overloading or excessive stress. Crestal bone loss that does not extend beyond the threads is commonly seen around implants and is not associated with implant failure or over loading in the log-term. The average crestal bone loss that can be seen within the first year of implant loading can range from 0-3 mm. Crestal bone loss in subsequent years should be less much less than 1 mm. Bacterial colonization and infection can then occur and contribute to the propagation of the bone loss but this is typically a secondary event. Emergence profile and cement reaction play a minor role.
What term describes the stimulation of osteoprogenitor cells to differentiate into osteoblasts that begins new bone formation?
Osteoinduction
Osteoconduction
Osteopromotion
Osteogenesis
Answer: A
Rationale:
Osteoinduction involves the stimulation of osteoprogenitor cells to differentiate into osteoblasts that then begin new bone formation. The most widely studied type of osteoinductive cell mediators are bone morphogenetic proteins (BMPs). A bone graft material that is osteoconductive and osteoinductive will not only serve as a scaffold for currently existing osteoblasts but will also trigger the formation of new osteoblasts, theoretically promoting faster integration of the graft.
Osteoconduction occurs when the bone graft material serves as a scaffold for new bone growth that is perpetuated by the native bone. Osteoblasts from the margin of the defect that is being grafted utilize the bone graft material as a framework upon which to spread and generate new bone. In the very least, a bone graft material should be osteoconductive. Osteopromotion involves the enhancement of osteoinduction without the possession of osteoinductive properties. For example, enamel matrix derivative has been shown to enhance the osteoinductive effect of demineralized freeze dried bone allograft (DFDBA), but will not stimulate de novo bone growth alone.
Osteogenesis occurs when vital osteoblasts originating from the bone graft material contribute to new bone growth along with bone growth generated via the other two mechanisms.
What disease causes collections of abnormal plasma cells that accumulate in bone marrow and interfere with the production of normal blood cells?
Multiple myeloma
Multiple sclerosis
Acute lymphocytic leukemia
Chronic Lymphocytic Leukemia
Answer: A
Rationale:
In multiple myeloma, collections of abnormal plasma cells accumulate in the bone marrow, where they interfere with the production of normal blood cells. Most cases of multiple myeloma also feature the production of a paraprotien—an abnormal antibody which can cause kidney problems. Bone lesions and hypercalcemia (high blood calcium levels) are also often encountered. Multiple myeloma is diagnosed with blood tests (serum protein electrophoresis, serum free kappa/lambda light chain assay), bone marrow examination, urine protein electrophoresis, and X-rays of commonly involved bones. Multiple sclerosis (MS) is a demyelinating disease in which the insulating covers of nerve cells in the brain and spinal cord are damaged.
Acute lymphocytic leukemia (ALL), also called acute lymphoblastic leukemia and acute lymphoid leukemia, is a blood cancer that results when abnormal white blood cells (leukemia cells) accumulate in the bone marrow. Chronic lymphocytic leukemia (CLL) is a typically slow-growing cancer which begins in lymphocytes in the bone marrow and extends into the blood. It can also spread to lymph nodes and organs such as the liver and spleen. CLL develops when too many abnormal lymphocytes grow, crowding out normal blood cells and making it difficult for the body to fight infection.
Which of the following is a contraindication to performing an MRI of the TMJ?
a. Cardiac pacemaker
b. Prosthetic hip implant
c. Orthodontic appliance
d. Dental implant
Answer: A
Rationale:
Cardiac pacemakers (Answer A) and implantable cardioverter defibrillators (ICDs) are currently considered a relative contraindication for patients referred for MR procedures. Cardiac pacemakers and ICDs have been suggested to present potential problems to patients undergoing MR procedures from various mechanisms. These include:
1) Movement and/or vibration of the pulse generator or leads
2) Temporary or permanent modification of the function (i.e., damage) of the device
3) Inappropriate sensing, triggering, or activation of the device
4) Excessive heating of the leads
5) Electromagnetic interference
The other choices (answers B, C, D) are not typically affected by the magnetic field and are not contraindicated.
A chemical peel with Jessner’s solution plus 35% Tricholoracetic acid (TCA) will penetrate:
A. the epidermis and papillary dermis layers
B. the epidermis, papillary dermis and upper reticular dermis layers
C. the epidermis, papillary dermis, upper and mid-reticular dermis layers
D. the epidermis, papillary dermis, upper, mid- and lower reticular dermis layers
Answer: B
Rationale: Chemical peels are classified according to their depth of penetration. These include: •Superficial •Medium •Deep
Superficial peels penetrate into the epidermis and papillary dermis (Answer A). Examples of superficial peeling agents include TCA (up to 30%), glycolic acid, salicylic acid (5-15%) and Jessner’s solution. Medium depth peels penetrate into the epidermis, papillary dermis and upper reticular dermis (Answer B). Examples of medium peeling agents include TCA (35-50 %), phenol (88%), and Jessner’s solution plus TCA (35%). Deep depth peels penetrate into epidermis, papillary dermis, upper and mid-reticular dermis (Answer C). Examples of deep peeling agents include Baker’s phenol and TCA >50%. Penetration into the lower reticular dermis is to be avoided in peels in order to avoid scarring and dermal atrophy.
Which of the following maxillary segmentalosteotomy techniques relies solely on a labial vascular supply?
Wassamund
Wunderer
Segmental alveolar
Lefort I segmental
Answer: B
Rationale:
Maxillary segmental osteotomies can be based on palatal or labial blood supplies, or both. The classic Wunderer technique for maxillary anterior segmental osteotomy has been employed to correct anterior maxillary protrusion, and involves premolar extraction or orthodontic creation of a space for ostectomy to set back the mobilized premaxillary segment. A transpalatal incision is made over the area of desired bone removal, followed by ostectomy and mobilization with preservation of the labial mucosa, followed by retropositioning of the premaxillary segment.
The Wassamund technique for premaxillary osteotomy can involve a labiobuccal incision and a palatal tunnel or tunneling of the labial and palatal segments, followed by desired ostectomy to allow a premaxillary setback. Likewise, most other isolated alveolar segmental osteotomies use a palatal pedicle with labiobuccal incision or tunneling. The Lefort I segmental osteotomy technique involved downfracture and mobilization of the entire maxilla, followed by segmentalization as desired; and is based on a palatal pedicle.
Reference:
Bevis R, Waite D. Maxillary Asymmetry. In: Bell W, Proffit W, White R. Surgical Correction of Dentofacial Deformities, Volume II. WB Saunders, Philadelphia, 1980 1541-43
The preauricular approach versus the retromandibular approach for management of a condyle fracture provides improved access to the:
posterior border of the mandible.
sigmoid notch.
antero-medially dislocated condylar head.
extracapsular subcondylar fracture.
Answer: C
Rationale:
The skin incision for the retromandibular incision begins approximately 0.5 cm below the earlobe and extends for approximately 3 cm. There are variations in the dissection but all procedures provide good access to the posterior border of the mandible and sigmoid notch. The preauricular incision is advantageous in accessing and reducing a high antero-medially displaced condylar head fracture. The incision, however, limits access to low extracapsular fractures or the distal segment when placing fixation. Excessive retraction when using the preauricular incision can result in nerve injury and facial muscular weakness. Alternatively, a second incision (e.g. submandibular incision) may be required to provide access for fixation.
Which of the following is a potential space that has no fascial borders?
Submasseteric space
Parapharyngeal space
Submandibular space
Medial ptyergoid space
Answer: A
Rationale: Most spaces of the head and neck are lined by fascia and are formed when the layers are split with the formation of a space-occupying collection of purulent material. These include the submandibular space, medial ptyerygoid space, parapharyngealspacesublingual space. The submasseteric space is a potential space only and is not lined by fascia. It becomes a definable space when purulent material forces itself between the masseter muscle and the lateral border of the ascending ramus. The direct irritation of the masseter muscle in submasseteric space infections is the main reason why these type of infections typically present with pain and severe trismus. Extensive involvement of the fascia-lined spaces has the potential to compromise the integrity of the airway.
The newer formulation of dantrolene, Ryanodex, is:
A. reconstituted with intralipid forming an emulsion which requires approximately 50% of the preparation time of Dantrium.
B. available as 250 mg vials of a sterile powder that is reconstituted with 60 mL sterile water.
C. administered at a dose that is less than the initial milligram dose of Dantrium, which is the original dantrolene forumation.
D. administered at an initial dose of 2.5 mg/kg TBW when malignant hyperthermia is first suspected.
Answer D
Rationale
Malignant hyperthermia is a condition related to the abnormality of the ryanodine receptor in skeletal muscle that results in a hypermetabolic reaction when the patient is exposed to triggering agents, such as succinylcholine and volatile inhalational anesthetic agents. Dantrolene is a skeletal muscle relaxant that is critical in managing malignant hyperthermia and reducing the mortality associated with the event. Every 30-minute delay in the administration of dantrolene is reported to double the incidence of complications associated with malignant hyperthermia. Dantrium (Revonton) was for many years the only preparation of dantrolene that was available. It came as a powder that required reconstitution. Twenty milligrams of dantirum was in each vial, which was reconstituted with 60 m: of sterile water. When reconstituting the medication, the vials had to be vigorously shaken. It was time consuming and required several staff members. Ryanodex is a newer preparation. It also comes as powder. 250 milligrams per vial which is reconstituted with 5 mL of sterile water. The vial is shaken to ensure an orange colored opaque suspension. The initial dosage for both preparations is 2.5 mg/kg TBW. Preparation time for the Dantirum is 860 seconds (14.3 minutes) compared to a preparation time for Ryanodex of 51 seconds.
Which of the following statement regarding amlodipine is correct?
A. It is a first line medication for initial treatment of Stage I hypertension in a Caucasian patient.
B. Amlodipine has been useful in control of premature ventricular contractions without structural heart disease.
C. A known complication of this medication is bradycardia.
D. This medication is preferred for hypertension therapy in a nondiabetic African American patient.
Correct answer: D
Rationale: Amlodipine belongs to the dihydropyridine (DHP) class of calcium channel blockers, and often used to reduce systemic vascular resistance and arterial pressure. Dihydropyridines mainly affect arterial vascular smooth muscle and lower blood pressure by causing peripheral vasodilation. Sometimes when they are used to treat hypertension, peripheral vasodilation and hypotension can lead to reflex tachycardia, which may be detrimental for patients who exhibit frequent idiopathic PVCs or those related to structural cardiac/cardiovascular pathology. For hypertensive patients in whom a potential tachycardia might be problematic, non-DHP calcium channel blockers (which have greater degrees of cardiac conduction suppression and less tachycardia potential) would be a more appropriate choice. According to JNC 8 guidelines, initial pharmacologic therapy for hypertension in Caucasian patients includes angiotensin II inhibitors (ACEI), angiotension receptor blockers (ARB), or thiazide diuretics. Population studies have shown that in African American patients without chronic kidney disease, calcium channel blockers (CCB) and/or thiazides are indicated for initial therapy.
