Complication rates after operations for benign thyroid disease

Assessment of different classification systems for predicting the risk of superior laryngeal nerve injury during thyroid surgery: a prospective cohort study

Background

A multitude of anatomical variations have been noted in the external branch of the superior laryngeal nerve (EBSLN). In this study, intraoperative neuromonitoring (IONM) was used to assess the potential value of the different classical EBSLN classifications for predicting the risk of EBSLN injury.

Methods

In total, 136 patients with thyroid nodules were included in this prospective cohort study, covering 242 nerves at risk (NAR). The EBSLN was identified by observing the cricothyroid muscle twitch and/or typical electromyography (EMG) biphasic waveform. The EBSLNs were classified by Cernea classification, Kierner classification, and Friedman classification, respectively. The EMG parameters and outcomes of vocal acoustic assessment were recorded.

Results

The distribution of Cernea, Kiernea, and Friedman subtypes were, respectively, Cernea 1 (40.9%), Cernea 2A (45.5%), Cernea 2B (10.7%), Kierner 1 (40.9%), Kierner 2 (45.5%), Kierner 3 (10.7%), Kierner 4 (2.9%) and Friedman 1 (15.7%), Friedman 2 (33.9%), Friedman 3 (50.4%). The amplitudes of EBSLN decreased significantly after superior thyroid pole operation, respectively, in Cernea 2A (193.7 vs. 226.6μV, P=0.019), Cernea 2B (185.8 vs. 221.3μV, P=0.039), Kierner 2 (193.7vs. 226.6μV, P=0.019), Kierner 3 (185.8 vs. 221.3μV, P=0.039), Kierner 4 (126.8vs. 226.0μV, P=0.015) and Friedman type 2 (184.8 vs. 221.6μV, P=0.030). There were significant differences in Fmax and Frange for Cernea 2A (P=0.001, P=0.001), 2B (P=0.001, P=0.038), Kierner 2 (P=0.001), Kierner 3 (P=0.001, P=0.038), and Friedman 2 (P=0.004, P=0.014). In the predictive efficacy of EBSLN injury, the Friedman classification showed higher accuracy (69.8% vs. 44.3% vs. 45.0%), sensitivity (19.5% vs. 11.0% vs. 14.0%), and specificity (95.6% vs. 89.9% vs. 89.9%) than the Cernea and Kierner classifications. However, the false negative rate of Friedman classification was significantly higher than other subtypes (19.5% vs. 11.0% vs. 14.0%).

Conclusion

Cernea 2A and 2B; Kierner 2, 3, and 4; and Friedman 2 were defined as the high-risk subtypes of EBSLN. The risk prediction ability of the Friedman classification was found to be superior compared to other classifications.

Experience of thyroid surgery at tertiary referral centers in Jazan Hospitals, Saudi Arabia

Background

Benign multinodular goiter (BMNG) is a common disease of the thyroid gland with palpable thyroid nodules that may be detected in 0.8%–1.5% of men and 5.3%–6.4% of women. Three major complications could be detected after total thyroidectomy: hemorrhage, recurrent laryngeal paralysis, and hypoparathyroidism.

Aims

The aim of this study was to review and assess the experience of total thyroidectomy in patients with BMNG at tertiary referral centers in Jazan Hospitals, Saudi Arabia.

Methods

A retrospective study was conducted on 320 patients diagnosed with BMNG and subjected to primary total thyroidectomy. Operative mortality and major complications [bleeding, recurrent laryngeal nerve (RLN) injury, and hypoparathyroidism] were recorded.

Results

Postoperative hemorrhage was reported in four patients (1.25%). Bilateral RLN injuries occurred in two patients (0.6%), whereas unilateral RLN injuries occurred in nine patients (2.8%). Permanent hypoparathyroidism was diagnosed in three patients (0.9%), while transient hypoparathyroidism occurred in eight patients (2.5%) and improved after 4 months.

Conclusions

Total thyroidectomy represents today the treatment of choice for BMNG. Proper preoperative preparations, meticulous surgical dissection with careful follow-up of patients will improve the surgical results and reduce postoperative complications.

Investigation on EMG Profiles of the Superior Laryngeal Nerve in a In Vivo Porcine Model

BACKGROUND

The electromyographic (EMG) profiles of external branch of the superior laryngeal nerve (EBSLN) have been defined and the optimal intensity of the stimulation of EBSLN in an in vivo porcine model has been explored.

MATERIALS

EMG was simultaneously registered by the surface of endotracheal tube and needle electrodes by applying a monopolar stimulation probe in 12 piglets (22 EBSLNs). Vagal nerve (VN), RLN and EBSLN were excited to record the EMG tracings and cricothyroid muscle twitch (CTM). VN, RLN and EBSLN were stimulated from 0.1 to 1.0 mA. Cmin and Cmax have been defined as the minimum and maximal stimulation to evoke an EMG response.

RESULTS

The stimulation resulted in a dose-response curve. Cmin were 0.19 mA (0.04-0.4), 0.19 mA (0.08-0.3) and 0.21 mA (0.1-0.4) for EBSLN, RLN and VN (p > 0.05) respectively. Cmax were 0.6 mA along with an amplitude value of 396 ± 330 μV, 0.5 mA including 1058 ± 382 μV, 0.8 mA coupled with 870 ± 382 μV, equally for EBSLN, RLN and VN (p > 0.05) respectively. No asymmetry of amplitude responses each side for EBSLN, RLN and VN (p = 0.317, p = 0.203 and p = 0.468, respectively) was noted. The amplitudes of EBSLN were significantly lower than RLNs and VN (42% of RLN and 50% of VN amplitude rates). Also, CTM twitch was always detectable with the stimulation of EBSLN.

CONCLUSIONS

Cmin and Cmax of EBSLN were comparable to RLN and VN standards. The amplitude stimulus-response curves of RLN, VN and EBSLN were highly variable. It has been suggested to apply a stimulation of 1.0 mA and a visual appreciation of CTM twitch for the identification of EBSLN.

Blood supply of the terminal part of the external branch of the superior laryngeal nerve

PURPOSE

The external laryngeal nerve (ELN) carries motor fibers to the cricothyroid and inferior pharyngeal muscles. Damage to the nerve may cause symptoms such as a monotone voice. One reason for these symptoms may be nerve injury due to inadvertent stretching, ligation or transaction of the nerve during the dissection of the superior pole of the thyroid gland. We hypothesized a new reason for the symptoms, an insufficient arterial blood supply to the nerve, and investigated this hypothesis.

METHODS

From 36 larynges, 52 sides (26 right and 26 left) were dissected under a surgical Zeiss-OpM1 microscope.

RESULTS

The arterial branch to the external branch of the superior laryngeal nerve originated from the posterior glandular branch of the superior thyroid artery in 26 (50%) sides, from the anterior glandular branch in 23 (44.23%) sides, from its trunk on one (1.92%) side, from the infrahyoid branch on one (1.92%) side and from the bifurcation of the superior thyroid artery at the level of separation of the anterior and posterior glandular branches on one (1.92%) side.

CONCLUSION

Devascularization of the ELN may lead to dysfunction, so this nerve's varied blood supply should be kept in mind when invasive procedures are performed in this region.

Efficacy of glycerol and flax seed oil as anti-adhesive barriers after thyroidectomy

BACKGROUND

We evaluated the effects of local flax seed oil and glycerol application for reducing adhesion formation after thyroidectomy.

MATERIAL AND METHODS

We randomly assigned 18 female Wistar albino rats (median weight: 275 g, median age: 4.5 mth) to 3 groups: 0.1 ml 0.9% NaCl, glycerol, and flax seed oil were sprayed in a perithyroidal area after thyroidectomy operation on all animals as anti-adhesive barriers. Rats were sacrificed on the postoperative 14th day and adhesions were evaluated macroscopically and microscopically.

RESULTS

The median macroscopic adhesion score was 3.0±0.0 in the 0.9% NaCl group, 1.33±0.52 in the glycerol group, and 1.67±0.53 in the flax seed oil group. The median histopathological fibrosis scores were 2.33±0.82, 0.67±0.52, and 0.83±0.75, respectively. Both glycerol and flaxseed oil group macroscopic and microscopic scores were significantly lower than the 0.9% NaCl group (p<0.05). There was no significant difference among the groups (p>0.05).

CONCLUSIONS

Glycerol and flax seed oil both decrease the incidence of post-thyroidectomy adhesion in rats, but glycerol is more effective.

Factors influencing morbidity after surgical management of malignant thyroid disease

OBJECTIVES

We performed a retrospective study of cases from 2005 to 2010 at an academic tertiary care center to analyze the factors that influence morbidity in surgical management of thyroid malignancy.

METHODS

The rates of recurrent laryngeal nerve (RLN) injury and hypoparathyroidism (HPT) were analyzed in the entire cohort. The comparison groups were 1) primary surgery versus revision; 2) total thyroidectomy versus total thyroidectomy combined with neck node dissection; and 3) two groups defined by surgical technique according to the RLN approach: group 1, in which the RLN was identified inferiorly in the tracheoesophageal groove, and group 2, in which the RLN was identified near the cricothyroid joint point of entry.

RESULTS

We reviewed 308 patients who underwent surgery for thyroid cancer. Thirty-six (11.7%) had temporary HPT, and 8 (2.6%) had permanent HPT. Of a total of 586 RLNs at risk, 16 (2.7%) had temporary damage and 2 (0.3%) had permanent damage. The incidences of temporary RLN injury significantly differed between the primary-surgery and revision-surgery groups (2.5% versus 15.6%; p = 0.001), and also between the groups with total thyroidectomy and thyroidectomy with neck dissection (1.2% versus 7.8%; p = 0.027). The incidences of temporary HPT were significantly different between the groups with primary surgery and revision surgery (6.6% versus 31.3%; p = 0.001), between the groups with total thyroidectomy and total thyroidectomy with neck dissection (4.7% versus 15.6%; p = 0.009), and between group 1 and group 2 (surgical technique in terms of RLN approach; 8.2% versus 17.9%; p = 0.011). Permanent HPT and permanent RLN injury both occurred rarely in this cohort, with no significant differences among comparison groups.

CONCLUSIONS

Our study shows a higher incidence of temporary RLN injury and teniporary HPT in revision surgery cases and in total thyroidectomy with neck dissection. Temporary HPT was significantly more common when the RLN was identified near the cricothyroid joint.

Intra- and postoperative complications in 137 cases of giant thyroid gland tumor

The intra- and postoperative complications resulting from surgery for giant thyroid gland tumors (diameter greater than 10 cm) present serious challenges to patient recovery. Although there are a number of methods, all have limitations. In this study, we present our experience with several complications of surgical treatment of giant thyroid gland tumors to increase the awareness and aid the prevention of these complications. A total of 137 consecutive patients who underwent surgical treatment in Henan Tumor Hospital were retrospectively analyzed. Statistics pertaining to the patients' clinical factors were gathered. We found that the most common surgical complications were recurrent laryngeal nerve (RLN) injury and symptomatic hypoparathyroidism. Other complications included incision site infections, bleeding, infection and chyle fistula, the incidence of which increased significantly with increasing extent of surgery from group I (near-total thyroidectomy) to group V (total thyroidectomy plus lateral neck dissection). Low complication rates may be achieved with more accurate knowledge of the surgical anatomy, skilled surgical treatment and experience. More extensive surgery results in a greater number of complications.

The factors related with postoperative complications in benign nodular thyroid surgery

Thyroid gland is an important endocrine organ because of its functions. Although the morbidity and mortality of thyroid surgery have decreased markedly, serious complications may still occur. The aim of this retrospective study was to identify the factors influencing the complications in benign nodular thyroid surgery. A total of 332 patients who underwent thyroid surgery between April 2004 and May 2008 were evaluated retrospectively to identify the factors influencing the complications. We found that in surgery lasting more than 90 minutes the risk of permanent recurrent laryngeal nerve (RLN) injury was high, daily drainage more than 50 cc increases the risk of seroma formation, retrosternal goiter surgery have higher risk for bleeding. The flap edema rates were high found in the operations made by resident surgeon and patients with size 3-4 thyroid glands. Low complication rates can be achieved after thyroidectomy with better knowledge of the surgical anatomy of the neck, thyroid pathology and required surgical treatment.

Terminal ligature of inferior thyroid artery branches during total thyroidectomy for multinodular goiter is associated with higher postoperative calcium and PTH levels

PURPOSE

To evaluate the impact of truncal versus terminal branch ligature of the inferior thyroid artery (ITA) on postoperative calcium and PTH plasma levels in patients undergoing total thyroidectomy for multinodular goiter.

METHODS

A prospective randomized study was performed comparing a group of patients that underwent either truncal ligature of the ITA (group 1) or terminal ligature of ITA branches (group 2).

RESULTS

A series of 126 consecutive patients with non-toxic euthyroid multinodular goiter underwent total thyroidectomy. Truncal ligature of the ITA was performed in 63 patients (group 1) and terminal branch ITA ligature in 63 patients (group 2). Postoperative ionized serum calcium (mmol/L) at 24 hours was significantly lower in group 1 than in group 2 patients (1.22 ± 0.06 vs. 1.25 ± 0.05, P<0.05) and at 48 hours (1.20 ± 0.05 vs. 1.23 ± 0.05, P<0.05). Mean postoperative PTH levels (pg/mL) at 4 hours after thyroidectomy were significantly lower in group 1 than in group 2 patients (22.32 ± 11.64 vs. 25.82 ± 12.87, P=0.044). Mean hospital stay (hours) was higher in group 1 than in group 2 patients (87.47 ± 41.04 vs. 70.34 ± 24.82, P<0.05).

CONCLUSION

This study shows that terminal ligature of ITA branches during total thyroidectomy for multinodular goiter is associated with higher mean postoperative calcium and PTH levels, and shorter hospital stay. However, no significant difference in terms of permanent hypoparathyroidism was observed between the two groups.

Surgical anatomy of the external branch of the superior laryngeal nerve

BACKGROUND

The variations in the anatomy of the external branch of the superior laryngeal nerve (EBSLN) are generally classified according to the relationship of the nerve to the superior thyroid artery, or the superior pole of the thyroid. Both artery and superior pole are themselves variable landmarks, and therefore are not consistent between subjects. We sought to examine EBSLN anatomy in relation to alternate, more consistent surgical landmarks.

METHODS

Fifteen hemi-larynges from 20 embalmed human cadavers were dissected anatomically. Each nerve was categorized using established classification systems, and terminal branching patterns were also noted. Nerve location was recorded in relation to three different constant anatomical structures: the laryngeal prominence, midline junction of the cricothyroid muscles and ipsilateral cricothyroid joint.

RESULTS

All cadavers were of European descent. The EBSLN had two branches to the cricothyroid muscle in 34% of cases. The EBSLN anatomical types found were mainly Cernea type 1 (80%), with 7% type 2a and 13% type Ni. An EBSLN was more likely to lie in an 'at risk' location if the subject was less than 160 cm tall. The EBSLN entered the crico-thyroid muscle at a median distance of 14 mm lateral from the laryngeal prominence and 8 mm inferiorly. The median distance from the medial-most point of the cricothyroid muscle junction was 14 mm laterally and 14 mm superiorly, and from the cricothyroid joint the entry lay a median distance of 10 mm superiorly and 11 mm medially.

CONCLUSIONS

The variability of EBSLN anatomy is again evident, as is the need for careful and knowledgeable surgical technique. New surgical landmarks for the relations of the insertion of the EBSLN reveal a deployment range for each, but one of more of these landmarks may prove useful in thyroid surgery.

Recurrent laryngeal nerve and voice preservation: routine identification and appropriate assessment - two important steps in thyroid surgery

INTRODUCTION

The aims of this study were to assess and compare vocal cord functions before and after thyroid surgery after intra-operative identification of recurrent laryngeal nerve.

PATIENTS AND METHODS

Recurrent laryngeal nerve (RLN) is seen intra-operatively in all cases undergoing thyroid surgeries. Vocal cord functions including any voice change were evaluated by indirect laryngoscopy (I/L) and direct laryngoscopy (D/L) before and after surgery.

RESULTS

Prospective study on 100 patients over 18 months with a total of 146 nerves at risk (NAR). Majority were women (n = 86) with mean age of 37.48 years (range, 13-60 years). RLN was seen in all patients and 19 patients complained of some change in quality of their voice after surgery. Evaluation by I/L and D/L at 6 weeks showed recurrent laryngeal nerve palsy (RLNP) in nine (47.36%) and five (26%) of these 19 patients respectively. Analysed according to total NAR, the incidence of voice change and temporary RLN palsy (I/L and D/L) at 6 weeks was still less at 13.01%, 6.16% and 3.42%, respectively. Voice change improved in all cases at 3 months with no RLNP palsy by I/L or D/L. All these 19 patients had undergone difficult or extensive surgery for malignancy, large gland, extratyhroidal spread or fibrosis.

CONCLUSIONS

Despite identification and preservation of RLN, patients can develop postoperative voice change and RLNP although all voice change cannot be attributed to damaged RLN. Proper assessment of vocal cord functions by I/L and D/L laryngoscopy is required to rule out injuries to these nerves. Risk of damage is higher in patients undergoing more difficult surgery.

Total thyroidectomy is safer with identification of recurrent laryngeal nerve

OBJECTIVE

To investigate the effect of recurrent laryngeal nerve (RLN) identification on the complications after total thyroidectomy and lobectomy.

METHODS

Total 134 consecutive patients undergoing total thyroidectomy or thyroid lobectomy from January 2003 to November 2004 were investigated retrospectively. Patients were divided into two groups: RLN identified (Group A) or not (Group B). The two groups were compared for RLN injury and hypocalcaemia.

RESULTS

The numbers of patients and nerves at risk were 71 and 129 in Group A, and 63 and 121 in Group B, respectively. RLN injury in Group A (0) was significantly lower than that in Group B (5 [7.9%]) patients, 7 [5.8%] nerves) for the numbers of patients (P=0.016) and nerves at risk (P=0.006). Temporary hypocalcaemia was significantly higher in Group A than in Group B (14 [24.1%] vs 6 [10.3%], P=0.049). Permanent complications in Group B were significantly higher than those in Group A (13 [20.6%] vs 4 [5.6%], P=0.009).

CONCLUSION

RLN injury was prevented and permanent complications were decreased by identifying the whole course and branches of the recurrent laryngeal nerve during total thyroidectomy.

Anatomical and surgical considerations of the external branch of the superior laryngeal nerve: a systematic review

The anatomical course of the external branch of the superior laryngeal nerve (EBSLN) is variable, and a consistent approach to its preservation during thyroid surgery is needed to reduce risk of post-operative voice impairment. Despite agreement that careful dissection in the region of the superior thyroid pole is required, there is no accepted 'best' approach, nor any universal acknowledgement that location of the EBSLN is actually necessary. The popular cernea classification of EBSLN has limitations, including its decreased reliability with increased thyroid size and its irrelevance in cases of 'buried' variants. * Recent work has identified factors such as ethnicity and stature in the prevalence of EBSLN variants. Consistent approaches to the post-operative detection of EBSLN injury are needed to build an accurate picture of the incidence of surgical nerve injury. Then a standardised approach to EBSLN preservation may emerge.

Determination of the function of the internal branch of the superior laryngeal nerve after thyroidectomy

BACKGROUND

Several unique complications of thyroidectomy exist because of its regional anatomy; they are well studied and reported. A majority of thyroidectomy patients report vague upper aerodigestive tract complaints. Despite this, no formal assessment of the integrity of the internal branch of the superior laryngeal nerve after thyroidectomy exists in the literature.

METHODS

Thirty three patients undergoing thyroidectomy were prospectively evaluated with preoperative and postoperative laryngopharyngeal sensory testing.

RESULTS

Preoperatively, 16 patients (49%) reported dysphagia, and 19 (58%) complained of globus sensation. Postoperatively, 24 (73%) patients complained of dysphagia, and 25 (76%) reported globus sensation. Preoperative sensory testing showed a mean sensory threshold of 2.79 +/- 0.51 mm Hg. The mean change in thresholds postoperatively was trivial (0.07 +/- 0.29 mm Hg), and did not differ significantly from zero (p = .19).

CONCLUSIONS

Although most patients report significant difficulty swallowing after thyroidectomy, the sensory nerve to the laryngopharynx remains intact and is not at risk during thyroid surgery.

Supervised surgical trainees perform thyroid surgery for Graves' disease safely

BACKGROUND

There is little information about the effect of operative experience and supervision of trainees on long-term outcomes after thyroid resection for Graves' disease (GD). The aim of this study was to compare the morbidity rate after thyroid resection performed by trainees vs consultant surgeons.

METHODS

Based on a cross-sectional design analysis with a median follow-up of 96 months (range, 12-216 months), long-term outcomes for 111 patients operated on by consultants were compared with those of 42 patients operated on by supervised trainees in an academic teaching hospital between 1987 and 2002.

RESULTS

Of the 111 patients operated on by the consultants, there were 25 (21.6%) cases of transient and 12 (10.8%) cases of permanent hypocalcemia and 10 (9.0%) cases of transient and 1 (0.9%) case of permanent recurrent laryngeal nerve (RLN) palsy. Of the 42 patients operated upon by the supervised trainees, there were 8 (21.4%) cases of transient and no permanent hypocalcemia, 3 (7.1%) cases of transient, and 1 (2.3%) case of permanent RLN palsy. Permanent complication rate of the entire group was low, and the grade of the primary surgeon made no difference in the occurrence of complications (P>0.05).

CONCLUSION

Supervised trainees can perform thyroid surgery for GD safely if a standardized surgical teaching program is available.

Thyroid nodule: A potentially malignant lesion; optimal management from a surgical perspective

Thyroid nodules are very common lesions, frequently detected by modern imaging methods (mainly ultrasonography). Despite that most thyroid nodules represent benign lesions, a small but significant percentage of them are malignant. Surgery is indicated when there is underlying malignancy (or suspicion for), pressure symptoms, or for cosmetic reasons. Total/near total thyroidectomy is the most radical procedure, which achieves cure, avoids the possibility of reoperation in the future (completion thyroidectomy), and facilitates postoperative management of the patient with underlying malignancy. Simple observation and thyroid hormone suppressive therapy are acceptable management options for patients with presumably benign thyroid nodules. Radioiodine therapy may be used for the management of patients with hyperfunctioning ("hot") thyroid nodules. Ablation of thyroid nodules (sclerosing therapy [alcohol injection] and laser photocoagulation) have been used for the in situ destruction of thyroid nodules; ablation therapy is currently viewed as experimental therapeutic method. Careful evaluation is required in order to avoid both overtreatment (mainly unnecessary surgery) as well as undertreatment of these potentially malignant, but highly curable lesions.

Recurrent laryngeal nerve palsy after thyroidectomy with routine identification of the recurrent laryngeal nerve

BACKGROUND

The aim of this study was to assess the risk of recurrent laryngeal nerve palsy (RLNP) after thyroidectomy with routine identification of the recurrent laryngeal nerve (RLN) during the operation.

METHODS

The present study was confined to 521 patients, 348 total lobectomies and 178 total thyroidectomies, treated by the same surgeon. Temporary and permanent RLNP rates were analyzed for patient groups with stratification of primary operation for benign thyroid disease, thyroid cancer, Graves' disease, and reoperation. Measurement of the RLNP rate was based on the number of nerves at risk. Twenty-six RLNs in 20 thyroid cancer patients with intentional sacrifice were excluded from analysis.

RESULTS

Forty RLNs (40 patients) developed postoperative RLNP. Complete recovery of RLN function was documented for 35 of the 37 patients (94.6%) whose RLN integrity had been ensured intraoperatively. Recovery from temporary RLNP ranged from 3 days to 4 months (mean, 30.7 days). Overall incidence of temporary and permanent RLNP was 5.1% and 0.9%, respectively. The rates of temporary/permanent RLNP were 4.0/0.2%, 2.0/0.7%, 12.0/1.1%, and 10.8/8.1% for groups classified according to benign thyroid disease, thyroid cancer, Graves' disease, and reoperation, respectively.

CONCLUSIONS

Operations for thyroid cancer, Graves' disease, and recurrent goiter demonstrated significantly higher RLNP rates. Invasion of RLN was identified in 19.4% of patients with thyroid cancer. Postoperatively, the RLN recovered in most of the patients without documented nerve damage during the operation. Total lobectomy with routine RLN identification is recommended as a basic procedure in thyroid operations.

Estudio multivariable de los factores de riesgo para desarrollar complicaciones en la cirugía del bocio multinodular

INTRODUCTION

Multinodular goiter (MG) accounts for a large volume of procedures performed in endocrine surgery departments. However, risk factors for postoperative complications have not been systematically investigated. The aim of the present study was to evaluate surgical outcomes in terms of morbidity and mortality through multivariate statistical analysis with a view to determining risk factors in MG surgery.

PATIENTS AND METHOD

A total of 672 patients who underwent surgery for MG were retrospectively reviewed. The variables analyzed were age, sex, prior surgery, disease duration, symptomatology, intrathoracic component, the surgeons experience, surgical technique, identification of structures, associated thyroid carcinoma and thyroid specimen weight. The chi-squared test, Students t-test and logistic regression analysis were performed.

RESULTS

Morbidity was 22% (n = 147) and mostly corresponded to hypoparathyroidisms and transitory recurrent lesions. Risk factors for developing these complications were symptomatic disease (p = 0.0131), hyperthyroidism (p = 0.0333), compressive symptoms (p = 0.0158), clinical grade of the goiter (p = 0.0482), surgical technique (p < 0.00001) and thyroid weight (p = 0.0302). Independent risk factors were surgical technique, hyperthyroidism and goiter grade. The definitive complication rate was 2.2% (n = 15), corresponding to six hypoparathyroidisms (0.9%) and 10 recurrent lesions (1.5%). The risk factor for their development was hyperthyroidism (p = 0.0037; RR = 2.8).

CONCLUSIONS

The main independent risk factor for complications after MG surgery is hyperthyroidism.

The superior laryngeal nerve: function and dysfunction

Despite long-standing clinical interest in SLN dysfunction, most aspects of this entity continue to require clarification. The replacement of the laryngeal mirror by flexible fiberoptic and rigid rod-lens laryngoscopy (including stroboscopy) and the resulting improvement in laryngeal visualization and documentation of examination has not resulted in a better definition of characteristic signs. Symptoms are often vague, and most are shared with other voice disorders. Under the circumstances, there is good reason to suppose that SLN dysfunction yields a clinical picture at least as heterogeneous as recurrent laryngeal nerve injury and a good deal more subtle. Faced with significant inconsistencies in clinical presentation, the clinician is hard-pressed to draw conclusions regarding prevalence, patterns of dysfunction, natural history, treatment, and even about its overall significance. EMG. used judiciously and complemented by frequency range testing, seems to hold more promise as a means of reliable diagnosis than laryngoscopic examination and may serve to resolve some of the confusion surrounding SLN dysfunction. It is equally important that the otolaryngologist guard against falling into the easy habit of attributing vocal disturbance that cannot be otherwise explained to SLN dysfunction in the absence of EMG evidence. If ambiguities surrounding SLN paralysis and paresis are to be clarified, diagnostic rigor is essential.