What is considered insensible loss?
Sweating, Evaporation from lungs due to anesthesia dry vapors, wound evaporation
How much insensible loss occurs in OMFS procedures?
How do you calculate volume status of an immediate postop patient?
1. Calculate Maintenance fluids utilizing 4:2:1 Rule (4cc/kg/hr for the first 10kg, then 2cc/kg/hr for the 2nd 10kg, then 1cc/kg/hr thereafter): e.g., 70kg pt =110cc/hour
2. Calculate total outs:
a. NPO from midnight until surgery (unless in-house and getting maintenance fluids) represents missed maintenance fluids: e.g., NPO at midnight to 8am= -880cc
b. Maintenance fluid during surgery: e.g., 4hr surgery=-440cc
c. Estimated blood loss x 3 (b/c blood is colloid): e.g., 550cc = -1650ccd. Insensible loss (3cc/kg/hr for OMFS): e.g., 70kg pt in 4hr surgery= -840cc
e. Urine output during case: e.g., -300cc
3. Calculate total ins:
a. Crystalloid given during surgery: e.g., 4000cc LR=+4000ccb. Colloid given during surgery (blood/albumin) x 3: e.g., 1 unit packed red blood cells (~250cc)=+750cc4. Add numbers to find status: e.g., pt is POSITIVE 200cc
What is ideal urine output for an adult? for a child?
1cc/hr/kg for child 40kg pt = 40cc/hr
0.5cc/hr/kg adult 70kg pt = 35cc/hr
If patient had Negative body balance of 1 liter how much do you have to change maintenance fluid if you want to do it slowly over 5hours?
70kg pt maintainence is 110cc/hour (1000cc/5hours = 200cc/hr) The patient would have to have fluid rate of 310 per hour for 5 hrs.
What ways can you check bloods loss?
Skin Turgor, Specfic gravity of urine, Orthostatic vital signs, skin temp (if hands are cold to the elbow there is a 10% blood loss)
1unit EBL represents what change in HCT?
-3% is correct but LBK might state 5%
What is considered orthostatic changes?
After waiting 2 min at new position HR increased >10 bpm or BP dropped >20mmHg
What are the causes of vertical maxillary excess?
Upper airway occlusion, i.e. enlarged tonsils
Mouth breathers their tongue is not against the palate shaping it.
LeFort I with impaction patient is complaining to excessive tearing. What is this called and what likely happened?
Blockage of the nasolacrimal duct with bone or edema or from over impaction
How far is the nasolacrimal duct from nasal floor?
What are the causes of post op 3rd molar infections with unerupted teeth?
1. Fracture of the mandible during extraction
2. Retained foreign body ie sponge
3. Hematoma under the flap that secondarily gets infected
4. Metastatic lesion in the jaw that secondarily infects
5. Immunocompromised host HIV, cancer, steroid dependent pt
When you harvest ribs for TMJ surgery you get called that the patient is having difficult breathing what likely happened?
On PE how can you diagnose pneumothorax?
Ausculation = decreased breath sounds on the affected side.
If you suspect pneumothorax what do you do next?
Place pt on 02, place pulse ox on patient
Check post op chest xray
Order STAT new chest xray
Name the sutures involved in ZMC fracture?
ZygomaticosphenoidalWhat are the Knight and North classifications for ZMC fractures?
Group I: nondisplaced fractures
Group II: Arch fractures only with classic three fracture lines producing V- shaped deformity
Group III: Unrotated body fx. - direct blow to zygomatic prominence. The
zygoma is driven posterior and medially. The infraorbital rim is displaced
inferior and medially at the buttress
Group IV: Medially rotated body fractures
Group V: Laterally rotated body fractures - superior displacement of inferior orbital rim with lateral displacement at the frontozygomatic suture
Group VI: Complex/comminuted fracturesIn 1961, Knight and North proposed a new anatomically based classification system of zygoma fractures (based on Waters view radiograph), which they hoped would help better determine the prognosis and treatment of such injuries.
Group I encompassed fractures with no significant displacement as evidenced clinically and radiographically. While fracture lines may be seen, their recommendation was that this group requires no surgical intervention. A soft diet and careful avoidance of any further injury is prudent.
Group II fractures include only those of the arch caused by a direct blow that buckles the malar eminence inward. This fracture is often associated with trismus. Often, this type of fracture can be treated satisfactorily by a Gillies approach or other standard techniques.
Unrotated body fractures, medially rotated body fractures, laterally rotated body fractures, and complex fractures (defined as the presence of additional fracture lines across the main fragment) belong to groups III, IV, V, and VI, respectively. Knight and North defined these groups by their stability after reduction. They found that 100% of group II and group V fractures were stable after a Gillies reduction, and no fixation was required. However, 100% of group IV, 40% of group III, and 70% of group VI were unstable after reduction and required some form of fixation.
Name the bones of the orbit? (Name clockwise or counterclockwise)
Roof: Frontal bone, Lesser wing of sphenoid
Medial: Maxilla, lacrimal, ethmoid, Body of sphenoid
Floor: Maxillary, palatine, Zygoma
Lateral Zygoma, Greater wing of the sphenoid
What two dissection approaches can be taken in lingual nerve explorations/repairs?
Where do you expect to find the proximal segment of the lingual nerve?
Between the medial pterygoid and the temporalis tendon
What is the OMENS classification? What does it stand for? ffforor?for?forfor?What cancers are likely to metastasize to the jaws?
Breast, Lung, Kidney, Prostate, Thyroid (LBK answer)
Women: breast followed by the adrenal, colo-rectum, female genital organs and thyroid
Men: lung, followed by the prostate, kidney, bone and adrenal. The most common location of the metastatic tumors was the mandible, with the molar area the most frequent site involved.
Hirshberg A, et al. Metastatic tumors to the jawbones: analysis of 390 cases.J Oral Pathol Med. 1994 Sep;23(8):337-41
When consenting for extraction of 3rd molars what is the risk for lingual or inferior alveolar nerve paresthesia vs anesthesia?
Lingual 1/1500 chance of paresthesia of these 10% will have permanent anesthesia
IAN: 1/750 chance of paresthesia of these 3% will have permanent anesthesia
Numbers vary by study this is what LBK states
Why is IAN more likely to regain function after injury during extraction?
Bony IAN canal acts as a conduit for regeneration
What is a Tinels Sign?
Steadmans Med Dictionary: Tinel's sign is elicited by percussing the skin over the median nerve just proximal to the carpal tunnel; when it is positive, the patient will complain of an electric sensation radiating into the thumb, index, middle, or ring fingers.
What is a Tinel-like Sign?
It can used to describe lingual nerve patients when one percusses over the site of lingual nerve injury and the patient gets a shock like sensation traveling down the tongue. This suggests that that nerve is regenerating. If compared over time the sensation will travel more distal on the tongue. This is to be distinguished from dysesthesia which is pain on percussion at the site of injury. It is best to banish this Sign from your vocabulary if youre in LBKs presence
What are the most stable to least stable skeletal movements during orthognathic surgery?
Maxilla up, Mandible forward, Chin any direction, Maxilla forward, Maxilla asymmetry, Maxilla up and mandible forward, Maxilla forward and mandible back, Mandible asymmetry, Mandible back, Maxilla down, Maxilla wider
What are the least stable skeletal movements during orthognathic surgery?
Maxilla widening or maxillary disimpaction
Why does one leave a 2-3mm posterior open bite when performing bilateral costochrondral rib grafts to the mandible ramus condyle unit?
It allows for settling of the graft helping to avoid a relapse open bite.
What are the stages of fracture healing with closed reduction?
Secondary Healing (Stages are Initial stage hematoma, Cartilaginous callus, Bony callus, remodeling)
What are the stages of fracture healing with open reduction with internal fixation?
Primary healing (requires excellent anatomic reduction, minimal mobility, good vascular supply)
Describe the process in which a non vascularized bone graft is integrated into the donor site?
What are the ways in which a mandible fracture can be reduced?
Closed, Open wires (semi rigid fixation), plates and screws (rigid fixation), external fixation
What constitutes rigid fixation for mandible fractures?
What are the LeFort I anatomic landmarks during surgery?
How many millimeters can you safely place an external fixation marker in the nasal bone for Le Fort I osteotomies?
What is the incidence of IAN anesthesia/paresthesia after BSSO?
What radiographic signs are associated with inferior alveolar nerve injury during third molar removal?