it is well known that uvci could happen post acd / f [ 17 ] .
an incidence of 24.2% has been reported in one prospective study when including the clinically unapparent injury .
only two cases of bilateral vocal cord injury ( bvci ) have been described in the english literature .
one was after a whiplash injury which , by itself or in combination with the very extensive procedure , could explain the bilateral involvement . in the other case the patient has a history of cardiac surgery that could have been the cause of a silent uvci [ 1 , 8 ] .
we are presenting a case of bvci with no indication of preoperative uvci in order to alert practitioners to this possibility .
a 46 year old male with a history of smoking , hypertension and alcoholism with no significant surgical history or other medical problems scheduled for acd for c 6 - 7 herniated discs . after establishing intravenous access and applying standard monitors ,
after a dose of 0.5 mg vecuronium , anesthetic induction was successfully achieved using fentanyl 250 mcg , thiopental / propofol , 140 mg/70 mg and succinylcholine 100 mg .
atraumatic endotracheal intubation ( eti ) was accomplished with size 8 tube inserted to 23 cm and secured at the lips uneventfully .
the surgery was preformed to the right side using a microscope for the dissection followed by the graft placement under fluoroscopy .
as the patient was awakened at the end of the surgery , the endotracheal tube was removed and the patient was taken to the recovery room in a stable condition with no abnormal neurological signs and oxygen saturation ( spo2 ) of 99% on 3l / m nasal oxygen .
the patient was noted to develop inspiratory stridor with sternal retraction and had a hoarse / whispering voice .
0.5 ml of racemic epinephrine ( 2.25% ) was administered by inhalation as well as 100 mg of intravenous hydrocortisone .
we entertained the possibility of vocal cord paralysis ( vcp ) and accordingly gave 1 mg of midazolam .
considering the risks of aspiration , the risks of trauma to the neck if the airway had to be established urgently without proper preparation for neck protection , which may lead to paralysis from spinal cord injury , and the severity of the patient 's symptoms ; all these facts alone with the need for a permanent airway device for ventilation favored performing a tracheostomy . following the tracheostomy ,
immediate postoperative evaluation could not identify any pathology for the bvcp . in a follow up visit six weeks later , it was found that the tracheostomy had been properly placed , the patient was able to eat and drink without difficulty , and he could also speak well .
laryngoscopy revealed that his vocal cords continued to be in a paramedian position ; therefore , it was not considered safe to remove the tracheostomy tube at that time .
a voice analysis study ( va ) indicated that his left vocal cord had some tone and some movement but his right vocal cord remained atonic .
a follow up visit for the removal of the tracheostomy tube was arranged with a local otolaryngologist in his home town .
. some proposed mechanisms of this surgical complication includes direct surgical trauma , nerve division or ligature , pressure or stretch induced neuropraxia , and postoperative edema [ 2 , 9 ] .
a uvci occurs mostly on the right vocal cord due to the fact that the right approach is the preferred one to avoid injury to the thoracic duct , which resides on the left side [ 2 , 4,9 ] .
while this would explain the recurrent laryngeal nerve injury on the right side , it would not explain the left side paralysis noted in our patient .
mark kriskovich et al . reported a vocal cord paralysis rate of 6.4% in 250 consecutive patients undergoing acd .
this was done by deflating the endotracheal tube cuff after placement of the surgical retractors and then re - inflating the cuff to a pressure of 15 mm hg .
when the paralyzed cord is near the midline ( paramedian ) , the voice may appear near normal although most of those patients may complain of voice fatigue .
this fact indicates that a patient may have normal voice but still have an underline injury .
we hypothesize that our patient could have had an unrecognized preexisting uvci . without a preoperative electromyographic study
, it would be hard to determine if one of the paralyzed cords was an older injury .
another explanation for our bvci is the endotracheal tube , which has been shown to lead to uvcp or bvci [ 11 , 12 ] .
vocal cord paralysis ( vcp ) as a complication of eti was reported to be 10 - 15% of all causes of vcp .
although it most commonly affects the left vocal cord , cases of bvci have been described from eti . also postoperative
vcp has been reported even in patients who had a laryngeal mask airway during surgery [ 1517 ] .
other causes that should be considered includes , but are not limited to , upper respiratory tract infection , thoracic tumor , stroke , diabetes neuropathy , and paradoxical vocal cord dysfunction [ 1 , 13 , 14 ] . before a definitive diagnosis could be made , conservative treatment included : oxygen by mask , systemic steroids , racemic epinephrine , as well as sedation .
after the diagnosis a permanent airway should be established if needed and that was our patient 's treatment .
given these occurrences , one should stay on guard for vcp postoperatively in their acd patients .
the addition of the technique of maintaining a specific cuff pressure and deflating followed by re - inflating it when the retractor is applied could be helpful in preventing vcp [ 2 , 3 ] .
we can not on the base of this one case report recommend a preoperative voice analysis study on every patient undergoing an acd simply because this would not be cost effective ; however , we do recommend a more detailed airway exam to include a voice exam with specific questioning about voice fatigue in order to identify patients at risk .
most importantly , we hope that this case presentation would alert the practitioners to the possibility of this rare complication after anterior cervical spinal surgeries .
 we present a rare case of bilateral vocal cord injury ( bvci ) following anterior cervical discectomy with fusion ( acd / f ) in a 47 year old man . 
 the patient experienced post - extubation stridor and whispering voice in the recovery room . 
 clinical assessment led to the diagnosis of bvci . 
 the patient was treated by tracheostomy and made a full recovery . 
 what is unique about this case is that the patient had no reason for a preexisting unilateral vocal cord injury ( uvci ) prior to this surgery . 
 there have been only two similar cases in the english literature in which the patients had a preexisting unilateral vocal cord paralysis ( uvci ) . 
 we recommend a more detailed preoperative airway exam to include a voice exam with specific voice fatigue questioning on all patients coming for acd / f . 
 such detailed assessment may uncover hidden uvci and allow a safer perioperative period . 