Complications of surgery of the thyroid and parathyroid glands

US residents experiences with intraoperative nerve monitoring in thyroid and parathyroid surgery

BACKGROUND

Understanding the patterns of IONM use and training among resident otolaryngologists is essential to ensure that the IONM skills and knowledge gained in residency are optimized for successful future practice of IONM.

METHOD

An electronic survey was distributed to US-based OHNS residents. Questions evaluated resident experience, implementation, knowledge and understanding of IONM for endocrine surgeries.

RESULTS

One hundred and seven OHNS residents participated, spanning all training levels and US geographic locations. The majority of residents received no didactic teaching on IONM (74.5%) nor had a clear troubleshooting algorithm in the event of a loss of signal (69.8%). The majority of residents were uncertain regarding the advantages/disadvantages of continuous versus intermittent IONM.

CONCLUSION

The knowledge gap found in our survey study suggests that greater teaching of IONM principles for endocrine head and neck surgeries in OHNS residency programs would help to ensure successful utilization in future practice.

Postoperative hypoparathyroidism after thyroid operation and exploration of permanent hypoparathyroidism evaluation

Background

To investigate the risk factors for hypoparathyroidism, discuss the prevention of postoperative hypoparathyroidism, and explore permanent postoperative hypoparathyroidism evaluation (PPHE).

Methods

A total of 2,903 patients with thyroid nodules were treated between October 2012 and August 2015. Serum calcium and intact parathyroid hormone (iPTH) levels were measured at 1 day, 1 month, and 6 months postoperatively. The incidence and management of hypoparathyroidism were analyzed. The PPHE was established based on the risk factors and clinical practice.

Results

A total of 637 (21.94%) patients developed hypoparathyroidism, and 92.15% of them had malignant nodules. The incidence rates of transient and permanent hypoparathyroidism were 11.47% and 10.47%, respectively. The iPTH level was lower in patients with malignant nodules who underwent total thyroidectomy (TT) and central-compartment neck dissection (CND). These factors were independently associated with the recovery rate of parathyroid function. The formula for PPHE is as follows: {iPTH} + {sCa} + {surgical procedure} + {reoperation} + {pathologic type}. A scoring system was developed, and we scored low, middle, and high risk of permanent postoperative hypoparathyroidism as 4-6, 7-9, and 10-13, respectively. The differences in the recovery rates of parathyroid function in several risk groups were statistically significant (p < 0.001).

Conclusion

Simultaneous TT and CND is a risk factor for hypoparathyroidism. The reoperation is not associated with hypoparathyroidism. Identification of parathyroid glands in situ and preservation of their vascular pedicles are key factors in managing hypoparathyroidism. PPHE can forecast the risk of permanent postoperative hypoparathyroidism well.

Standardized Intraoperative Neuromonitoring Procedure is Feasible in Transoral Endoscopic Thyroidectomy

BACKGROUND

Intraoperative neuromonitoring in thyroid surgeries has become popular, but the standardized manner of intraoperative neuromonitoring during transoral endoscopic thyroidectomy vestibular approach (TOETVA) is not well established. This study evaluated the feasibility of using a standardized intraoperative neuromonitoring method for TOETVA.

METHODS

Medical records of consecutive patients who underwent TOETVA with intraoperative neuromonitoring were retrospectively reviewed. Patients were positioned before intubation to prevent tube migration, then intubated using video laryngoscopy. The electromyography amplitudes of the vagal nerves and the recurrent laryngeal nerves were checked before (V1, R1) and after (V2, R2) thyroid resection. V1 and V2 signals were evaluated using a long ball tip stimulator with a stimulus current of 3 mA. R1 and R2 signals were obtained using the stimulus current of 1 to 3 mA.

RESULTS

Forty-two patients (3 males and 39 females) were included. Lobectomy was performed in 40 patients (95.2%) and total thyroidectomy in 2 (4.8%). Pathologic diagnoses were 30 papillary thyroid carcinomas, 2 follicular thyroid carcinomas, and 9 benign diseases. Conversion to open surgery occurred in 1 patient due to bleeding. Thus, 43 nerves at risk in 41 patients were analyzed. V1 and R1 signals were detected from all nerves. The mean V1 and R1 amplitudes were 738.7±391.4 μV and 804.4±347.5 μV, respectively, and 38 (88.3%) and 39 (90.7%) nerves had R1 and V1 amplitudes of more than 500 μV. There were 2 cases (4.6%) of transient recurrent laryngeal nerve injury. R2 and V2 signals were detected in the 41 remaining nerves. The mean R2 and V2 amplitudes were 917.2±505.2 μV and 715.7±356.2 μV, respectively, and 36 (87.8%) and 32 (78.0%) nerves had respective R2 and V2 amplitudes of more than 500 μV.

CONCLUSIONS

Intraoperative neuromonitoring could be performed in a standardized manner in TOETVA, and the quality of intraoperative neuromonitoring was excellent. Further studies are needed to verify the feasibility of the current approach.

Subclassification of Bethesda Atypical and Follicular Neoplasm Categories According to Nuclear and Architectural Atypia Improves Discrimination of Thyroid Malignancy Risk

BACKGROUND

Although The Bethesda System for Reporting Thyroid Cytopathology has provided clinicians with a standardized classification scheme for the diagnosis of thyroid fine-needle aspiration cytology (FNAC) specimens, the indeterminate categories of Bethesda III (B3)-atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS)-and Bethesda IV (B4)-follicular neoplasm/suspicious for follicular neoplasm (FN/SFN)-continue to pose challenges with regards to ideal diagnostic and therapeutic management. Having previously demonstrated the presence of nuclear atypia as a high-risk subgroup in B3, the objective of this study was to evaluate the malignancy rates in the B4 subgroup with nuclear atypia.

METHODS

A retrospective review of all thyroid FNACs diagnosed as B4 (FN/SFN) between 2008 and 2015 was conducted at a tertiary referral center in Singapore. Data on patient demographics, sonographic features, and final histological diagnosis were collected. This was compared to data from a previous analysis on all nodules diagnosed as B3 (AUS/FLUS) over a similar period.

RESULTS

A total of 137/309 (44.3%) and 88/111 (79.3%) FNACs diagnosed as B3 and B4, respectively, underwent surgical excision yielding final histopathological diagnoses. The malignancy rate of B4 was 31/88 (35.2%) compared to B3, which was 37/137 (27.0%). Subclassification based on the presence of architectural versus nuclear atypia showed significantly higher malignancy rates in B4 nodules with nuclear atypia (21.8% vs. 57.6%; p < 0.01). These findings corroborate previous results within the B3 category (malignancy rate of 14.7% vs. 36.8%; p < 0.01). The only sonographic features predictive of malignancy were the presence of macrocalcifications in B4 compared to irregularity of margins in B3.

CONCLUSION

The presence of nuclear atypia identifies subgroups with significant differential malignancy risks within both the B3 and B4 categories. This supports the notion that subclassification is a useful risk stratification tool that can guide diagnostic and therapeutic management of indeterminate thyroid nodules with heterogenous risk profiles.

Use of prophylactic oral calcium after total thyroidectomy: a prospective study

OBJECTIVE

The aim of this study was to evaluate the use of prophylactic oral calcium after total thyroidectomy in the prevention of symptomatic hypocalcemia, and to develop a rational strategy of oral calcium supplementation following this type of surgery.

SUBJECTS AND METHODS

Prospective study including 47 patients undergoing total thyroidectomy from January 2007 to February 2012. The patients were allocated to one of the following groups: I (no postoperative calcium) or II (oral calcium 3 g per day). Oral calcium was started at the first postoperative day and administered until the sixth postoperative day. The patients were followed up for a minimum of 6 months and evaluated with a minimum of five measurements of ionized calcium: preoperative, 16 hours after surgery, seventh postoperative day, and at postoperative days 90 (PO90) and 180 (PO180). The cohort included three men and 44 women, of whom 24 (51.9%) had benign thyroid disease, and 23 had suspected or confirmed malignant disease.

RESULTS

When compared with Group II, Group I had significantly higher rates of postoperative biochemical hypocalcemia at PO1 and PO180, and of symptomatic hypocalcemia at PO1, PO7, and PO90. Other data were not significantly different between the groups.

CONCLUSION

We conclude that postoperative calcium supplementation effectively prevents symptomatic and biochemical hypocalcemia after total thyroidectomy, and can be safely used after this procedure. The presented strategy of oral calcium supplementation may be implemented in a viable manner.

Postoperative Hypoparathyroidism and the Viability of the Parathyroid Glands During Thyroidectomy

OBJECTIVES

To prevent hypoparathyroidism after thyroidectomy, preservation of the parathyroid glands and their vascularity are essential. The aim of this study was to determine the association between postoperative parathyroid function and the viability of the parathyroid glands during thyroidectomy.

METHODS

We prospectively analyzed 111 patients who underwent total thyroidectomy and in whom all 4 parathyroid glands were preserved in situ during the operation. The surgeons scored the viability of each parathyroid gland from 0 (normal) to 3 (severely compromised viability) based on its gross appearance and vascularity intraoperatively. The index of parathyroid viability score (IPVS) was defined as the sum of the viability scores of the 4 parathyroid glands. We evaluated the relationship between postoperative parathyroid function and IPVS.

RESULTS

Transient hypoparathyroidism occurred in 25 patients (22.5%), and permanent hypoparathyroidism in 4 patients (3.6%). The IPVS were significantly different in the three groups: 2.87±1.46 in the normal group, 3.68±1.41 in the transient hypoparathyroidism group and 7.50±1.00 in the permanent hypoparathyroidism group. The rates of transient hypoparathyroidism were 13.6% in patients with IPVS 0-2, 23.8% in patients with IPVS 3-4, and 42.9% in patients with IPVS 5-6. All the patients with IPVS of 7 or more had permanent hypoparathyroidism.

CONCLUSION

IPVS is correlated with the incidence of hypoparathyroidism. It could be a good quantitative indicator of the probability of hypoparathyroidism after thyroidectomy.

Prevalence and patterns of intraoperative nerve monitoring for thyroidectomy

Objective

To estimate the patterns of use of intraoperative recurrent laryngeal nerve (RLN)-monitoring devices during thyroid surgery by otolaryngologists in the United States.

Methods

A questionnaire was mailed to 1685 randomly selected otolaryngologists, representing approximately half of all otolaryngologists currently practicing in the United States. Topics covered included training history and current practice setting, use and characteristics of use of RLN monitoring during thyroid surgery, as well as history of RLN injury and/or subsequent lawsuits. X 2 test was used to examine associations between monitor usage and dependent variables, and odds ratios calculated by logistic regression were used to refine the magnitude of these associations. RESULTS: A total of 685 (40.7%) of questionnaires were returned, and 81 percent (555) of respondents reported performing thyroidectomy. Of those, only 28.6 percent (159) reported using intraoperative monitoring for all cases. Respondents were 3.14 times more likely to currently use intraoperative monitoring if they used it during their training. Surgeons currently using intraoperative RLN monitoring during thyroidectomy were 41 percent less likely to report a history of permanent RLN injury. Further information about surgeon background and rationale for decisions regarding RLN monitor usage are discussed.

Conclusions

Presently, the majority of otolaryngologists in the United States do not report regular usage of RLN monitoring in their practices. Surgeon background and training, more so than surgical volume, significantly influenced the use of intraoperative RLN monitoring.

Surgical management of thyroid cancer

Thyroid cancer is the most common endocrine neoplasm; however, it only accounts for less than 1% of all human malignances. Thyroid cancers are divided into well differentiated and non-well differentiated cancers, according to their histology and behavior. The surgical management options of well-differentiated thyroid cancer include total or near-total thyroidectomy, subtotal thyroidectomy and lobectomy plus isthmusectomy. The extent of surgery for thyroid cancer continues to be an area of controversy. Complications associated with thyroid surgery are directly proportional to the extent of thyroidectomy and inversely proportional to the experience of the operating surgeon. They occur less frequently with good surgical technique and better understanding of surgical anatomy, and include wound healing and infections (seroma, hematoma and wound infection), nerve injury, hypoparathyroidism, hypothyroidism, postoperative hemorrhage and respiratory obstruction.

An applied anatomical study on the recurrent laryngeal nerve and inferior thyroid artery

PURPOSE

The aim of this study was to provide some important information about the morphology and topography of the recurrent laryngeal nerve (RLN) and inferior thyroid artery (ITA), which significantly helps localize and protect the RLN in neck surgery, especially in thyroid surgery.

METHODS

Eighty adult cadavers (160 sides) fixed with formalin were dissected, analyzed and measured.

RESULTS

(1) 87.5% of the RLNs gave off multiple branches like a tree; the incidence of the RLN loop, connecting one branch to another was 3.125%; in 9.375%, one branch of RLN combined with cervical sympathetic chain (CSC) or superior laryngeal nerve (SLN). (2) A double RLN appeared in four sides, a non-recurrent inferior laryngeal nerve appeared in two cases. (3) In two cases, the RLN communicated with both of the SLN and the CSC near thyroid gland. (4) Most of the ITAs was derived from thyrocervical trunk, and divided into two or three branches before entering the thyroid gland. (5) Three ITAs gave off esophageal branch, one ITA gave off tracheal branch, one right ITA originated abnormally. (6) On the left side, the RLN was behind the ITA in 86.25% of the cases, in front of the artery in 7.5%, the nerve was between artery branches in 2.5%, the artery was between nerve branches in 1.25%, and was among the combined in 2.5%. On the right side, the RLN was in front of the artery in 75.0%, behind the artery in 10.0%, among the branches of the artery in 5.0%, 10.0% the branches of both nerves and artery were interlaced that the relationship between the branches of the nerve and the artery was uncertain.

CONCLUSIONS

Because of the variability of the RLN and ITA and the complicated relationship between them, it is necessary to dissect and recognize the RLN to avoid mistaking, ignoring, and misligating of the nerve before ligating the ITA.

Intra- and postoperative parathyroid hormone-kinetics do not advocate for autotransplantation of discolored parathyroid glands during thyroidectomy

BACKGROUND

Thyroidectomy continues to pose the risk of typical complications, including postoperative hypocalcemia and permanent hypoparathyroidism. The strategic decision on how to preserve parathyroid hormone (PTH) secretion relies on assessing the viability of the parathyroid glands (PGs). The aim of this study was to assess parathyroid discoloration as an indicator for loss of parathyroid function.

METHODS

The prospective study included 29 patients (24 women, 5 men; age 53.2 ± 13.0 years) who underwent near-total or total thyroidectomy. An intra- and postoperative PTH and calcium monitoring was performed. The intraoperative situs of the PGs was documented by a study protocol. The patients were grouped in three categories: group A, 12 patients with four visualized and normally colored PGs; group B, 13 patients with four visualized and three or four discolored PGs; group C, 4 patients who had undergone autotransplantation of two PGs.

RESULTS

Compared to group A, groups B and C showed sharper intraoperative PTH declines. PTH values recovered more quickly in group B than in group C. However, no significant differences in PTH kinetics were found in the general linear model for repeated measures (p = 0.132). However, a significantly higher incidence of protracted hypocalcemia-related symptoms for more than 14 postoperative days was found for group C (50.0%) than for groups A (0%) and B (0%; p = 0.011). None of the patients developed permanent hypoparathyroidism.

CONCLUSIONS

The function of discolored PGs is only transiently impaired and recovers within a short time after surgery. Our observations do not support autotransplantation as a generally applicable first-line intervention for discolored PGs in the absence of other criteria for autotransplantation.

Immediate post-parathyroidectomy stridor resolved with intravenous calcium

A 73-year-old woman underwent an uncomplicated focused parathyroidectomy for an adenoma. Immediately after extubation she developed respiratory distress and her airway became compromised. No obvious cause could be found for the stridor and no response was obtained from nebulised adrenaline (norepinephrine). An intravenous bolus of calcium provided immediate but temporary relief. Lasting relief was obtained following the administration of an intravenous calcium infusion. Serology later confirmed a small decrease in calcium concentrations but at the time of the respiratory compromise the values were still within normal range.

Surgical Anatomy of the Recurrent Laryngeal Nerves and its Clinical Applications in Chinese Adults

PURPOSE

When removing the thyroid gland, great care must be taken to avoid damaging the recurrent laryngeal nerves (RLNs). The present study aims to present a clear picture of certain anatomical features of the RLNs in relation to the inferior thyroid artery (ITA), the tracheoesophageal groove (TE), Berry's ligament, and the inferior cornu of the thyroid cartilage in Chinese adults.

METHODS

We removed a collective 120 RLNs from 60 Chinese adult cadavers (52 men and 8 women), and examined their anatomic course and relationship on both sides.

RESULTS

The right and left RLNs were found in the tracheoesophageal groove in 78.3% and 91.3% of cases, respectively. Both RLNs were found posterior to and to the right of the ITA in 80% of cases, and one was found on the left side of the ITA in 91.7%. Most of the RLNs were within 3 mm of Berry's ligament, with a laryngeal entry point about 0.8 cm below and just anterior to the inferior horn of the thyroid cartilage.

CONCLUSIONS

The inferior cornu of the thyroid cartilage is a reliable landmark in identifying the RLNs. Racial variations between Caucasians and Chinese may explain some anatomic differences.

A safe and reliable technique for visualization of the laryngeal recurrent nerves in the neck

BACKGROUND

The risk of an injury of the laryngeal recurrent nerve is an important issue during any surgical procedure in the lower neck.

METHODS

Based on our experience with the transcervical-subxiphoid bilateral videothoracoscopic maximal thymectomies, we developed an original technique of visualization for both of these nerves. The key point of the presented technique is the dissection in the lower part of the neck, beneath the level of the thyroid gland. The central step is the division of the deep cervical fascial layers covering and obscuring the recurrent nerves. Preservation of the deepest layer protects the nerves from an injury.

RESULTS

We used this technique in 100 consecutive transcervical-subxiphoid bilateral videothoracoscopic maximal thymectomies without any case of permanent recurrent nerve palsy.

CONCLUSION

The presented technique is safe, reliable, and relatively simple. It may be used during an extended thymectomy, as well as during a thyroid resection and other operations in the lower neck.

Influence of muscle relaxation on neuromonitoring of the recurrent laryngeal nerve during thyroid surgery

BACKGROUND

The influence of muscle relaxation on the intra-operative neuromonitoring of the recurrent laryngeal nerve during thyroid surgery is unclear.

METHODS

In a prospective study involving 200 patients undergoing elective thyroid surgery, the influence of muscle relaxation on neuromonitoring of the recurrent laryngeal nerve was investigated. The patients received balanced anaesthesia with oxygen-nitrous oxide-isoflurane, and rocuronium bromide was used as the non-depolarizing neuromuscular blocking agent. The degree of relaxation was monitored continuously by accelerometry [twitch (% TW)]. Summed action potentials (SAcP) obtained from the vocalis muscle were characterized by the area under the electromyographic curve expressed in millivolt seconds.

RESULTS

Evoked potentials were obtainable in all patients and at all time points. With decreasing neuromuscular blockade a significant increase in the potentials evoked at the vocalis muscle was observed. At 0% TW SAcP was 1.27 (SD 1.02) mV s. An increase in TW to 10% was accompanied by an increase in SAcP to 2.68 (2.01) mV s (P<0.01). At a TW of 25%, mean SAcPs of 5.08 mV s were recorded.

CONCLUSIONS

There was a significant difference in the degree of relaxation of the adductor pollicis muscle and the vocalis muscle. The laryngeal muscles exhibited a shorter response time than the adductor pollicis and recovered more quickly. These results confirm the feasibility of intra-operative neuromonitoring of the recurrent laryngeal nerve during neuromuscular blockade.

Unilateral and bilateral surgery for parathyroid disease

The principles of successful parathyroid surgery, regardless of the approach, demand a clear understanding of the philosophy behind the surgical exploration. A systematic approach, founded in science and refined by experience, is necessary to achieve long-term, reproducible surgical success. This article discusses the underlying logic and the advantages and disadvantages of the two basic approaches to parathyroid pathology: unilateral and bilateral cervical exploration. The authors do not to advocate a particular technique;instead, they provide a conceptual framework to surgical parathyroid disease upon which more advanced discussion can be built.

Management of primary hyperthyroidism: toward minimal access surgery

Fifteen years ago, bilateral exploration of the neck was dogma in parathyroid surgery. Now, less invasive procedures can be used to target lesions identified by new tests such as dual-phase Sestamibi scanning or intraoperative documentation of parathyroid hormone (PTH) level changes after removal of a parathyroid gland. A hand-held gamma probe can be used for intraoperative detection of high-uptake lesions, and video-assisted endoscopic surgery has been used successfully. With these new techniques, surgical exploration can be confined to one side of the neck through smaller incisions associated with better cosmetic results. The operating time is reduced, and in some cases the procedure can be done under local anesthesia. The objective of this article is to describe recent changes in the management of parathyroid adenoma requiring surgery.

Should Female Patients Undergoing Parathyroid-Sparing Total Thyroidectomy Receive Routine Prophylaxis for Transient Hypocalcemia?

Hypocalcemia following parathyroid-sparing total thyroidectomy is frequent and can prolong hospital stay. We undertook this study to identify preoperative predictors of postoperative hypocalcemia useful in the postoperative management of these patients. We examined patients undergoing total thyroidectomy for benign disease with preservation of at least three parathyroids from January 2000 to January 2001. Low serum calcium was considered below 8.0 mg/dL. Age, gender, preoperative serum calcium, thyroid stimulating hormone (TSH), T3, T4, albumin, cholesterol, and tryglicerides were compared in patients with normal and low serum calcium level on the second postoperative day and on discharge day by using χ2 test and a model of logistic regression. Data were reported using their frequency distribution among the two groups of patients. Eighty patients, 60 females (F) and 20 males (M), underwent parathyroid-sparing total thyroidectomy. On second postoperative day, hypocalcemia occurred in 42 patients, and 56 per cent were symptomatic. Only female gender (88% F vs 12% M) ( P < 0.05) and TSH <0.27 mUI/mL (38% vs 18%) ( P < 0.05) predicted hypocalcemia. Similarly, female gender predicted hypocalcemia in a logistic regression analysis ( P < 0.05). On the day of discharge, 22 patients had low serum calcium levels, and 50 per cent were symptomatic. At this time, only TSH value <0.27 mlU/mL significantly predicted hypocalcemia (48% vs 17%) ( P < 0.05). This was confirmed in a logistic regression analysis ( P < 0.05). All but one patient (98%) eventually returned to normal serum calium levels. Despite preservation of parathyroids, transient symptomatic hypocalcemia is common after total thyroidectomy. Female gender and low TSH serum level predicted hypocalcemia. Therefore, female patients undergoing total thyroidectomy with preoperative low TSH levels should receive calcium prophylaxis to decrease morbidity, shorten hospital stay, and decrease costs.

Assessment of parathyroid autotransplantation for preservation of parathyroid function after total thyroidectomy

BACKGROUND

Hypoparathyroidism with permanent hypocalcemia is a well-recognized complication after thyroid surgery.

AIM

This study was conducted to assess the role of immediate parathyroid autotransplantation in the preservation of parathyroid function after total thyroidectomy.

PATIENTS AND METHODS

Twenty-eight patients had autotransplantation of parathyroid glands resected or devascularized during total thyroidectomy. Data were collected prospectively regarding demographics, indication for surgery, operative procedure, pathologic diagnosis, number of glands transplanted, and subsequent course. Thyroid nodules were evaluated by ultrasonography, radionuclide scanning, and/or fine-needle aspiration cytology. All patients had serum ionized calcium, phosphorus, and intact parathyroid hormone (PTH) levels measured preoperatively and monitored regularly postoperatively for a period of 14 weeks and again at 6 months after operation. Patients were categorized into three groups according to the number of glands transplanted: one (group 1, n = 6), two (group 2, n = 14), or three glands (group 3, n = 8). In three other volunteers, one parathyroid gland was transplanted in the brachioradialis and subjected to electron microscopy 1, 2, and 4 weeks after transplantation.

RESULTS

Total thyroidectomy was performed for malignant disease in 16 patients (57.1%) and for benign disease in 12 (42.9%) patients. All patients reverted to asymptomatic normocalcemia without the need for any medications within 4 to 14 weeks. Normal levels of serum markers were regained slower when one gland was transplanted compared with two or three glands (P <.01). Electron microscopic examination showed evidence of ischemic degeneration in the transplanted tissues 1 week postoperatively. Regeneration started by the second week and coincided with normalization of PTH levels. Optimum resting and nearly normal status of parathyroid tissue was achieved by the fourth week.

CONCLUSIONS

This study showed that active PTH production coincides with regeneration of parathyroid cells and that autotransplantation of at least two resected or devascularized glands during total thyroidectomy nearly eliminates permanent postoperative hypoparathyroidism, thus improving the safety of total thyroidectomy performed for malignant or benign disease.

Can we rely on pathologic parameters to define conservative treatment of papillary thyroid carcinoma?

Papillary thyroid carcinoma is the most common malignant tumor of the thyroid and usually behaves in an indolent fashion. At most institutions these tumors are treated by near-total or total thyroidectomy followed by radioactive iodine ablation. The 2 main reasons for this extensive treatment include high rate of multicentricity in papillary carcinoma and difficulty in ablating large thyroid remnants with radioactive iodine after partial thyroidectomy. Some authors believe, however, that this treatment protocol may not be justified in all cases of papillary carcinoma. We analyzed 253 total thyroidectomies performed for papillary thyroid carcinoma for the following pathologic variables: tumor size, presence of tumor capsular and/or vascular invasion, intrathyroidal spread, tumor in the contralateral lobe, and lymph node metastases. Tumors measuring less than 1 cm and those with extrathyroidal soft tissue extension were excluded from this study. Among 253 cases (197 females, 56 males, age range 14-88 years), the primary tumor size ranged from 1-9.5 cm; 162 cases were completely encapsulated. Tumor capsule invasion was seen in 139 (86%) and vascular invasion was present in 32 (13%) cases; of these 27 (11% of the total) patients showed both tumor capsule and vascular invasion. Seventy-four (29%) patients showed tumor in the contralateral lobe; in 35 (47%) of these cases the contralateral tumor measured less than 1.0 cm. Lymph nodes were sampled in 106 cases, metastases were present in 67 (67/106 = 63%) and only 16 cases with lymph node metastases showed contralateral tumors. No significant correlation was noted between tumor size, occurrence of contralateral tumors, and lymph node metastases. Seventy-one percent of cases included in this study failed to show contralateral tumors. Hence, pathologic parameters such as lack of vascular invasion and lack of multifocality may be used to identify patients who can benefit from conservative therapy alone.

Risk of injury to the external branch of the superior laryngeal nerve in thyroidectomy

OBJECTIVE

To establish in the Mexican population with thyroid disease the risk of injury to the external branch of the superior laryngeal nerve (EBSLN) based on its anatomical position.

STUDY DESIGN

Non-randomized comparative clinical trial.

METHODS

Seventy-three patients subjected to thyroidectomy because of thyroid nodule in which the EBSLN was identified and classified. The dependent variable was Cernea's classification of the EBSLN, and the independent variables were weight (in grams) of the nodule, side studied, gender, and age. For statistical analysis, chi2 test, Fisher's Exact test, and analysis of multiple variables (analysis of variance) were used.

RESULTS

We studied 73 patients; 64 (87.62%) were women and 9 (12.38%) were men (average age, 39.3 years [age range, 17-73 y]; median age, 40 y; mode, 40 y; SD +/- 23.4 y). Regarding location of the EBSLN, for pathological lobes, 78.1% were located in a high-risk position and for nonpathological lobes, 72.7%. Comparative analysis between sides and relation between weight and classification revealed no statistical significance.

CONCLUSION

The frequency of high-risk position for EBSLN lesion in our milieu was higher than that reported in series from other countries and races.

Relationship between the recurrent laryngeal nerve and the inferior thyroid artery: a study in corpses

The anatomical relationship between the recurrent laryngeal nerve (RLN) and the inferior thyroid artery (ITA) was studied in 76 embalmed corpses, 8 females and 68 males. In both sexes, the RLN lay more frequently between branches of the ITA.; it was found in this position in 47.3% of male corpses and 42.8% of female ones. On the right, RLN was found between branches of the ITA in 49.3% of the cases, anterior to it in 38.04%, and posterior in 11.26%. On the left, the RLN lay between branches of the ITA in 44.45%, posterior to the ITA in 37.05%, and anterior to it in 18.05% of the cases. In 62.68% of the cases, the relationship found on one side did not occur again on the opposite side. There was a significant difference (p<0.05) in the distribution of the 3 types of relationships between the RLN and the ITA, on the right and on the left. Racial variations could contribute to an explanation of the differences observed by authors of different countries in the relationship between the RLN and the ITA.

Parathyroid biopsy to facilitate the preservation of functional parathyroid tissue during thyroidectomy

BACKGROUND

The preservation of viable parathyroid tissue, either by preserving parathyroid glands in situ with an intact blood supply or by autotransplantation, is an integral element of thyroid surgery. There is a general impression that nonviable parathyroid glands can be recognized on the basis of black or purple-black discoloration of the gland. We came to believe that this is not a reliable way to assess the viability of parathyroid glands because we observed that when we excised parathyroid glands (with the intention of reimplanting them) in situations where it was not feasible to preserve their blood supply, they did not become discolored.

METHODS

To assess the status of the parathyroid blood supply, we performed incisional biopsies of suspected parathyroid glands during 14 consecutive thyroid operations (9 hemithyroidectomies, 1 completion thyroidectomy, 4 total thyroidectomies), and observed the biopsy site for evidence of active bleeding.

RESULTS

Thirty-four of 36 possible parathyroid glands were histologically confirmed. Seventeen bled actively from the biopsy site and were preserved in situ. The other 17 were felt to be nonviable: 5 were severely discolored (black) and either no bleeding or minor venous oozing was seen when they were biopsied; 12 with normal coloration (3 were harvested prior to biopsy), did not bleed actively following an incisional biopsy. Parathyroid glands that were judged to be devascularized were autotransplanted into the sternocleidomastoid muscle.

CONCLUSIONS

The absence of discoloration is not a reliable way to determine whether the parathyroid blood supply is intact. Biopsy of the parathyroid glands during thyroid surgery facilitates the identification of devascularized parathyroid glands that can be salvaged with autotransplantation.

Parathyroid preservation during thyroid surgery

PURPOSE

Even though thyroid surgery is generally quite safe, permanent hypoparathyroidism is a very distressing complication. The incidence of hypoparathyroidism is directly proportional to the extent of thyroidectomy, and inversely proportional to the experience of the surgeon. It is also related to the extent of invasion of thyroid cancer and of the degree of dissection in the tracheo-esophageal groove. The incidence reported in the literature varies between 1% to 29%. Total thyroidectomy results in a higher incidence of hypoparathyroidism.

MATERIALS AND METHODS

This report describes experiences with 600 thyroidectomies over a period of 11 years. The major indications for surgery included suspicion or proof of malignancy, compression symptoms, and substernal goiters. Twenty-six patients underwent surgery for Graves' disease. There were 221 men and 379 women, ranging in age from 16 to 89 years; 88% of the patients had benign disease, whereas 12% of the patients had malignant pathology. The surgical procedures included 62 total thyroidecotmies, 188 subtotal thyroidectomies, and lobectomy and isthmectomy in 350 patients.

RESULTS

Meticulous tracheo-esophageal groove dissection, identification of parathyroids and their preservation, including the blood supply, was routine in each case. Even in patients undergoing unilateral lobectomy, every effort was made to preserve the parathyroids. If any of the parathyroids or its blood supply was injured, it was autotransplanted in the sternomastoid muscle. Only two patients developed temporary hypoparathyroidism.

CONCLUSION

Parathyroid autotransplantation is performed whenever one or more of the parathyroids are damaged. Parathyroid preservation during thyroid surgery is crucial in the overall management of thyroid diseases.

Risks of complication following thyroidectomy

OBJECTIVE

Because hypoparathyroidism is a serious complication of thyroidectomy, we attempted to elucidate factors determining the risk of this postoperative outcome.

SETTING

Four tertiary care hospitals in Albuquerque, New Mexico.

PATIENTS

A retrospective study of 142 patients who underwent total or subtotal thyroidectomy between 1988 and 1995.

MEASUREMENTS AND MAIN RESULTS

Permanent hypoparathyroidism was defined as hypocalcemic symptoms plus a requirement for oral vitamin D or calcium 6 months after thyroidectomy. Factors analyzed to determine their contribution to the risk of persistent postoperative hypoparathyroidism were the indication for thyroidectomy, performance of a preoperative thyroid needle biopsy, type of surgery, postoperative pathology, presence and stage of thyroid carcinoma, resident surgeon involvement, and specialty of the surgeon performing the procedure. Surgical specialty and stage of thyroid carcinoma were independent risk factors for persistent postoperative hypoparathyroidism by multivariate analysis. Nine (29%) of 31 patients who had thyroidectomy by otolaryngologists met criteria for permanent hypoparathyroidism, and 6 (5%) of 111 patients who had thyroidectomy by general surgeons met the same criteria (p < .001). Adjustment for the effect of stage did not eliminate the effect of specialty (p = .006), and adjustment for the effect of specialty did not eliminate the effect of stage (p = .02), on the occurrence of postoperative hypoparathyroidism.

CONCLUSIONS

We conclude from our data that patients undergoing thyroidectomy by an otolaryngologist may be at a higher risk of permanent postoperative hypoparathyroidism than patients who undergo thyroidectomy by a general surgeon. This may reflect differences in case selection or surgical approach or both.

Preservation of recurrent laryngeal nerve invaded by differentiated thyroid cancer

OBJECTIVE

This study was undertaken to determine whether the recurrent laryngeal nerve involved in differentiated thyroid carcinoma could be preserved.

SUMMARY BACKGROUND DATA

Few investigations have provided definitive results concerning preservation of the recurrent laryngeal nerve involved in thyroid cancer. Complete excision with resection of the recurrent laryngeal nerve reportedly did not improve survival over incomplete excision in differentiated thyroid carcinoma.

METHODS

A retrospective study was performed with the medical records of 50 patients with differentiated carcinoma and preoperative normal vocal cord function to investigate outcomes of recurrent laryngeal nerve preservation including local recurrence, prognosis, and postoperative vocal cord function. The recurrent laryngeal nerves on 1 or both sides were preserved in 23 patients (the preserved group), whereas the involved recurrent laryngeal nerve of the other 27 patients was resected (the resected group).

RESULTS

Backgrounds of patients were similar between the resected and preserved groups. The number of patients with recurrences in each group was similar, and incidence of local, regional, and distant metastatic recurrences were not different between the groups. Postoperative overall survival of the preserved group was similar to that of the resected group (p = 0.1208). More than 60% of patients or of nerve at risk in the preserved group restored normal vocal cord function within 6 months. Some functional vocal cord movement was recognized in 80% of patients or of nerve at risk. All patients in the resected group including patients with nerve anastomosis showed permanent paralysis of the ipsilateral vocal cord.

CONCLUSIONS

These results suggested that the recurrent laryngeal nerve, even if infiltrated by differentiated thyroid cancer, is worthwhile to preserve for maintenance of postoperative vocal cord function without affecting the incidence of local recurrence or prognosis.

Clinical and laboratorial correlation of postoperative hypocalcemia after extensive thyroidectomy

The medical records of 84 patients submitted to extensive thyroidectomy from January 1991 to April 1995 were reviewed and the data was analyzed in order to verify a correlation between postoperative laboratories results and physical findings suggestive of hypocalcemia. It was verified that there was hypocalcemia in 51.2 percent of the patients, of which only 18.6 percent presented symptoms. It was concluded that asymptomatic hypocalcemia is frequent in extensive thyroidectomy and a routine screening for serum calcium in the postoperative period following thyroidectomy and calcium reposition must be systematic.

Practical management of post-thyroidectomy hematoma

Thyroid diseases and surgery for thyroid neoplasms are both very common. Several complications of thyroidectomy are well known. Some of these are quite disturbing, such as recurrent laryngeal nerve injury and permanent hypoparathyroidism. However, postoperative hematoma often in the recovery room may be fatal. Close observation and early intervention are of utmost necessity in the post-thyroidectomy period. In a series of 600 thyroidectomies performed over a period of 11 years, eight patients developed postoperative hematoma. Seven of them underwent re-exploration, while one patient was treated conservatively. Two patients had second re-exploration for hematoma reaccumulation. All patients recovered very well after re-exploration except one elderly patient who required ventilatory support due to poor pulmonary reserve; after a week of ventilatory support and a tracheostomy, she too recovered well. One patient had the hematoma re-explored as late as 24 hours after the operation, while the remainder were re-explored within 4-6 hours after the initial procedure. Because of the extent of edema of the larynx and pharyngeal wall, it is very important that a senior, experienced person perform intubation in these patients. It is also very important to recognize that when the patients lie down flat, they may develop acute airway distress; hence, one must be prepared to intubate them emergently. We recommend close recovery room observation after thyroidectomy and early exploration and evacuation of hematoma in all patients who develop postoperative hematoma. A conservative approach may be considered in selected patients with minimal hematoma and no progression. However, it generally takes a long time for the hematoma to resorb. A better understanding of the complications of thyroidectomy will minimize morbidity and make thyroidectomy a safer procedure and a surgical triumph.