[Display of different injuries of recurrent laryngeal nerve in laryngeal electromyography].

OBJECTIVE: To study the display of different types injuries of recurrent laryngeal nerve (RLN) in laryngeal electromyography (LEMG). METHODS: LEMGs of one hundred and forty-seven patients (147 sides) with traumatic unilateral vocal cord paralysis (UVCP) were studied. After LEMGs, the RLNs exploration operations were performed. The condition of RLNs injury and laryngeal muscles was observed and recorded during the operation. RESULTS: The severe injuries of RLNs were found during operation. The types of injuries were listed as ligation (58 cases), adhesion (28 cases) and cut (61 cases). The waveform morphology of LEMG was recorded less in the patients with the RLNs cut than that in the patients with the RLN ligation or adhesion, respectively. 75.4% RLNs cut showed spontaneous waveform while 96.4% RLNs adhesion and 94.8% RLNs ligation. When the RLN was cut off, single pattern was showed oftener. When the RLN was adhered or ligated, mixed pattern was showed oftener. 92.9% RLN adhesion showed misdirect-regeneration-potentials while 70.7% RLN ligation and 24.6% RLN cut. There were significant difference between two types, but the compound muscular active potential (CMAP) amplitude wasn't significantly different. Evoked amplitude could be recorded in 91.4% patients with ligation and its amplitude was (23.6 +/- 8.1)%, in 85.7% patients with adhesion and its amplitude (16.3 +/- 5.2)%, in 29.5% patients with cut and its amplitude (2.6 +/- 4.2)%. CONCLUSIONS: The display of different injuries of RLN in LEMG presents significant difference. If RLN was cut off, the CMAP might be recorded in most cases. The clinical injury of RLN often is followed by sub-clinic reinnervation.

[Glottic measurement and vocal evaluation after three surgical techniques in the treatment of bilateral vocal cord paralysis].

OBJECTIVE: To evaluate postoperative glottic area and vocal quality of three various surgical techniques for treating bilateral vocal cord paralysis, including laser arytenoidectomy (Group A, 24 cases), reinnervation of the posterior cricoarytenoid muscle by phrenic nerve (Group B, 9 cases) and arytenoidectomy accompanying lateral cordopexy by extralaryngeal approach (Woodman's procedure, Group C, 13 cases). METHODS: 46 cases suffered from bilateral recurrent laryngeal nerve injury were included in our study. The pre-postoperative glottic measurement and vocal acoustic parameters were analyzed. RESULTS: The decannulated cases in group A and group B and group C were 22, 8, 13 respectively. The post-operative mean maximal glottic area was (47.2 +/- 7.4) mm2, (78.3 +/- 16.0) mm2, (48.1 +/- 6.5) mm2 respectively. Group B cases glottic area was larger than that of group A and group C (t value were 4.46 and 3.85, P value were 0.000 and 0.001). No significant difference was found between group A and group C (t = 1.68, P = 0.101). After surgery, in group A, 17 cases voice quality was the same compared with that of before surgery, and 7 cases voice quality had become worse; In group B, the voice quality had become better in 5 cases, completely recovered in 1 case, and had not change in 3 cases; In group C, the voice quality had become deteriorated in 10 cases and no change in 3 cases. And in group B, ipsilateral diaphragm paralysis in 9 cases after surgery, whose vital capacity and forced vital capacity had decreased to 72%-84%, 76%-84% of that before the surgery respectively; and the diaphragm mobility had recovered by 35%-76% respectively, while vital capacity and forced vital capacity had become 93%-97%, 91%-98% of that before the surgery. In Group B, all cases' pulmonary function was normal half a year postoperatively. CONCLUSIONS: Reinnervation of the posterior cricoarytenoid muscle by phrenic nerve seems to be best procedure with better post-operative voice and larger glottic area. Although the sufficient airway for decannulation can be acquired in Group A and Group C, but most of patients in Group A had pre-operative vocal level and badly abnormal in Group C.

[Prevention and therapy of cerebrospinal fluid leakage after translabyrinthine acoustic neuroma removal].

OBJECTIVE: To evaluate the modified wound closure technique and other methods for preventing and treating the cerebrospinal fluid (CSF) leakage after removal of acoustic neuroma by translabyrinthine approach. METHODS: In a series of 85 cases of acoustic neuroma surgery, two kinds of technique of wound closure, the traditional (as first group) and the modified (as second group), have been subsequently used to prevent CSF leakage. The incidences of CSF leak were analyzed respectively. Conservative and surgical treatments were applied to treatment the CSF leak. RESULTS: In the first group, the CSF leak was 19.5% (8/41), and that of second group was 2.3% (1/44). There was significant difference between them (P = 0.013). The CSF leak mainly occurred in large acoustic neuromas surgery with traditional wound closure technique. Among 9 cases of CSF leaks, 3 were controlled by conservative method, 5 by one single revision surgery and one by two revisions. CONCLUSIONS: The revision technique of wound closure could significantly reduce the incidence of CSF leakage after acoustic neuroma removal by translabyrinthine approach. The revision surgery is an effective method for stopping the CSF leak.

[Long-term follow-up of autogenous fat injection for unilateral vocal cord paralysis].

OBJECTIVE: To study the long-term results of autogenous fat injection for unilateral vocal cord paralysis. METHODS: Twenty cases with unilateral vocal cord paralysis were treated by autogenous fat injection into the thyroarytenoid muscle to achieve medialization. The patients were divided into 3 groups by hoarse degree before operation, all of them were followed more than 12 months with serial video laryngoscope and voice evaluation. The ratio between paralyzed vocal cord upper surface and that of the normal vocal cord were adopted as the measurement for the vocal cord volume changes before and after operation. RESULTS: 1. The volume of paralyzed vocal cord was increased. The degree of hoarse and normalized noise energy (NNE) were evaluated by objective methods after operation. 2. The hoarse symptom was less severe after operation than that before operation. The cure cases 3 to 6 months and over 12 months after operation were nearly the same. 3. NNE of over 12 months and 3 to 6 months after operation were not significantly different, but the postoperative NNE were different with that before operation. CONCLUSIONS: Autologous fat injection was an effective method for treating unilateral vocal cord paralysis, and the long term effects were reliable.

[Diagnosis and management of sulcus vocalis].

OBJECTIVE: To clarify the pathophysiology of sulcus vocalis and to develop a more rational approach to treatment. METHODS: Twenty-nine cases of sulcus vocalis patients were divided into three classification: Type I is a physiologic variant and no dysphonia (11 cases). Types II (sulcus vergeture, 13 cases) and III (sulcus vocalis, 5 cases) are characterized by severe dysphonia and loss of vibratory activity. Eighteen cases of dysphonia were treated by surgery and phonation training. The operations included fat injection into vocal cords (9 cases of types II and 1 cases of types III, including 1 case of types III of second operation), fat implantation into sulcus vergeture after incision (4 cases of types II and 1 cases of types III) and undermining of the mucosa and sulcus vocalis resection (4 cases of types III, including 1 case of second operation). Phonatory function and video laryngostroboscopic data were evaluated before and after surgery and phonation training treatment in 18 patients. The mean follow-up time was 15.3 months. RESULTS: Ten cases of types II had excellent results after fat injection into vocal cords (n = 6) and fat implantation into sulcus vergeture after incision (n = 4). Three cases of types II improved after fat injection into vocal cords. Three cases of type III had excellent results after sulcus vocalis resection. One case of type III had excellent results by Second operation (sulcus vocalis resection) after fat injection into vocal cord. One case of type III improved by Second operation (fat injection into vocal cords) after fat implantation into sulcus vergeture after incision. No postoperative complications were noted. CONCLUSION: Accurate classification of sulcus vocalis is important and then adapt treatment to different types. Fat implantation into sulcus vergeture to type II and sulcus vocalis resection to type III were the best choice methods.

[Glottic measurement and vocal evaluation before and after adult arytenoidectomy].

OBJECTIVE: To study minimal glottic area which can acquire sufficient airway for decannulation and maximal glottic area which can maintain preoperative vocal function on adult bilateral vocal cord paralysis with unilateral arytenoidectomy. METHODS: Sixteen adult received microscopic right arytenoidectomy with Diomed-25 laser under general anaesthesia and sustained laryngoscope from September 1998 to February 2003. The pre-postoperative glottic measurement and vocal acoustic parameters were analyzed. RESULTS: The postoperative maximal glottic area, maximal posterior glottic width and maximal opening angle between bilateral vocal cords of the 15 decannulated cases were (45.93 +/- 6.56) mm2, (4.97 +/- 0.73) mm and (24.34 +/- 4.74) degrees respectively. Compared with preoperative period, there were significant difference. Pre-postoperative acoustic parameters (Jitter, Shimmer, harmonics-noise ratio) were analyzed and no significant difference were found (P > 0.05, but there are significant difference in NNE (normalized noise energy) and MPT (maximum phonation time) (P < 0.05). Except for three cases whose postoperative glottic area were more than 50. 1 mm2, there were no significant difference in pre and postoperative NNE (P > 0.05). The minimal glottic area decannulated was 38.0 mm2. The more opening maximal glottic area, the greater of NNE because of bigger closing gap. Noticeable increase of NNE was observed when maximal opening glottic area was up to 50.1 mm2. CONCLUSIONS: The minimal glottic area for decannulation should be 38.0 mm2, and the maximal glottic area for maintaining preoperation vocal function should be 50.1 mm2 on adult bilateral voca cord paralysis with laser aryntenoidectomy.

[Comprehensive prognostic value of spontaneous and evoked electromyography in laryngeal paralysis].

OBJECTIVE: To determine the comprehensive prognostic value of spontaneous and evoked electromyography (EMG) in laryngeal paralysis. METHODS: The characteristics of laryngeal EMG of 91 cases with unilateral vocal cord paralysis (VCP) after thyroid surgery were assessed. All cases were divided into four groups according to the interval of laryngeal EMG after onset, which were group one (2 months shorter, n = 13), group two (2 to 4 months, n = 23), group three (4 to 6 months, n = 36), group four (6 months longer, n = 19). The waveform morphology and the amplitude of laryngeal EMG and the highest evoked compound muscular active potential (CMAP) of thyroarytenoid muscles were examined and analyzed during voluntary tasks. The potential amplitude was showed by the percentage of that of the healthy lateral. The criterion of evaluation on evoked potential was attained by calculating statistical confidence interval. RESULTS: The highest evoked CMAP in group one was significantly lower than that of the others (P < 0.05), but no significant difference was observed between group two and group three (P > 0.05), so group two and group three were analyzed together. There were 2 recovered cases and 11 unrecovered cases in group one. On the basis of this criterion that a positive prognosis for laryngeal recovery was indicated when the evoked CMAP presented and there was no misdirect generated potential, correct prognostic rate was 92% (12/13). There were 11 recovered cases and 48 unrecovered cases in group two and three. The highest evoked CMAP was much higher in the recovered than in the unrecovered, significant difference was observed between them (P < 0.001). On the basis of the criterion that a positive prognosis for laryngeal recovery was indicated when the highest evoked CMAP was higher than 26. 4%, correct prognostic rate was 90% (53/59). On the basis of the criterion that a positive prognosis for laryngeal recovery was indicated when there was no misdirect generated potential and the highest evoked CMAP was higher than 26.4%, correct prognostic rate was 93% (55/59). When the interval from onset to laryngeal EMG recovering was longer than 6 months, none of these patients had return of vocal cord mobility whatever were the outcomes of laryngeal EMG. CONCLUSIONS: Correct prognostic rate can be improved if the prognosis of VCP in different courses is judged respectively by analyzing comprehensively spontaneous and evoked EMG.

[Nerve exploration and decompression for traumatic recurrent laryngeal nerve injuries induced by thyroid gland surgery].

OBJECTIVE: To show the findings of recurrent laryngeal nerve injury exploration and find out therapeutic effects, indications and timing of nerve decompression for traumatic recurrent laryngeal nerve injury induced by thyroid gland surgery. METHODS: In this study there were 87 patients with recurrent laryngeal nerve injury, including 65 for nerve exploration and 22 for nonsurgical treatment. During nerve exploration, the types, severity of laryngeal nerve injuries and laryngeal muscular mass were studied. Nerve decompression was performed in these 14 patients whose compressing sutures or compression due to cicatricial hypertrophy were received nerve decompression. RESULTS: Injuries caused by thyroid gland operations mostly are of suture ligation (43%) and nerve severance (48%); simple scar compression was found only in 6 cases (9%). Atrophy of the laryngeal muscles was not very serious in patients with a course less than 6 months. In 10 patients with a course less than three months, nerve decompression restored normal functional abductor and abductor motion of the vocal cord in 9 patients and had no effects in one. Although functional motion of vocal cord was not seen in one case with a course less than 3 months and 4 cases between 3 and 5 months, the mass and tension of the reinnervated vocal cord became much the same as the contralateral normal vocal cord, thus resuming symmetric vibration of the vocal cords and physiological phonation. Although nonsurgical treatment improved severe hoarseness, it didn't restore normal functional motion of the vocal cord and normal voice. CONCLUSIONS: Nerve exploration showed a primary rule for recurrent laryngeal nerve injury induced by thyroid gland surgery. Early and mid-stage recurrent laryngeal nerve exploration and decompression may restore normal motion of the glottis, and it suggested laryngeal delayed reinnervation may help patients with a course more than 6 months.