Michael Hermann

Laryngeal recurrent nerve injury in surgery for benign thyroid diseases: effect of nerve dissection and impact of individual surgeon in more than 27,000 nerves at risk.

ObjectiveTo evaluate the effect of recurrent nerve dissection on the incidence of recurrent laryngeal nerve injury (RLNI) and to analyze the performance of individual surgeons. Summary Background DataDissection of the recurrent nerve is mandatory in total thyroidectomy, but its relative merit in less extensive resections is not clear. The reported rates of RLNI differ widely; this may reflect a variation in the performance of individual surgeons. MethodsThe authors studied the incidence of RLNI in primary surgery for benign thyroid disease during three periods in a single center. In period 1 (1979–1990; 9,385 consecutive patients, 15,865 nerves at risk), the recurrent nerve was not exposed. In period 2 (1991–1998; 6,128 patients, 10,548 nerves at risk), dissection of the recurrent nerve was the standard procedure. Global outcome and individual performance in these two periods were compared and presented to the surgeons. The effect of this quality control procedure was tested in 1999 (period 3; 930 patients, 1,561 nerves at risk). ResultsExposure of the recurrent nerve significantly reduced the global rate of postoperative and permanent RLNI. Some but not all surgeons improved their results by recurrent nerve dissection (e.g., permanent RLNI rates ranged from 0% to 1.1%). The documented significant differences in individual performances did not affect the outcome in period 3. The extent of nerve dissection was a source of variability; the rate of permanent RLNI averaged 0.9%, 0.3%, and 0.1% for surgeons who only localized, partially exposed, and completely dissected the recurrent nerve, respectively. ConclusionsRecurrent nerve dissection significantly reduces the risk of RLNI. Extensive dissection facilitates visual control of nerve integrity during resection and is therefore superior to a more limited exposure of the nerve. Quality control can improve the global outcome and identify the variability in individual performance. This cannot be eliminated by merely confronting surgeons with comparative data; hence, it is important to search for the underlying causes.

Neuromonitoring in Thyroid Surgery: Prospective Evaluation of Intraoperative Electrophysiological Responses for the Prediction of Recurrent Laryngeal Nerve Injury

Objective:We evaluated the ability of neuromonitoring to predict postoperative outcome in patients undergoing thyroid surgery for different indications. Summary Background Data:Neuromonitoring has been advocated to reduce the risk of vocal cord palsy and to predict postoperative vocal cord function. Methods:Three hundred twenty-eight patients (502 nerves at risk) were studied prospectively at a single center. Neuromonitoring was performed with the Neurosign 100® device by transligamental placement of the recording electrode into the vocalis muscles. Cumulative distribution of stimulation thresholds was determined by stepwise decreases in current (1 mA to 0.05 mA) for both the vagus and the recurrent nerve. Patients were grouped according to surgical risk (benign and malignant disease, reoperation for benign and for malignant disease). Results:If the electrophysiological response was correlated to postoperative vocal cord function, the sensitivity of neuromonitoring was modest (86% in surgery for benign disease) to low (25% in reoperation for malignant disease); the positive predictive value was modest (overall rate 62%) but acceptable (87%) if corrected for technical problems. Specificity and negative predictive values were high (ie, overall >95%). Stimulation thresholds were not augmented in 11 patients, in whom postoperative palsy developed despite normal intraoperative recordings. Similarly, an electrical field response was elicited in 14 of 21 patients with preoperative vocal cord palsy. Electromyographic recordings did not reveal an abnormal amplitude or a decline in nerve conduction velocity. Conclusions:Neuromonitoring is useful for identifying the recurrent laryngeal nerve, in particular if the anatomic situation is complicated by prior surgery, large tissue masses, aberrant nerve course. However, neuromonitoring does not reliably predict postoperative outcome.

German Association of Endocrine Surgeons practice guidelines for the surgical treatment of benign thyroid disease

IntroductionBenign thyroid disorders are among the most common diseases in Germany, affecting around 15 million people and leading to more than 100,000 thyroid surgeries per year. Since the first German guidelines for the surgical treatment of benign goiter were published in 1998, abundant new information has become available, significantly shifting surgical strategy towards more radical interventions. Additionally, minimally invasive techniques have been developed and gained wide usage. These circumstances demanded a revision of the guidelines.MethodsBased on a review of relevant recent guidelines from other groups and additional literature, unpublished data, and clinical experience, the German Association of Endocrine Surgeons formulated new recommendations on the surgical treatment of benign thyroid diseases. These guidelines were developed through a formal expert consensus process and in collaboration with the German societies of Nuclear Medicine, Endocrinology, Pathology, and Phoniatrics & Pedaudiology as well as two patient organizations. Consensus was achieved through several moderated conferences of surgical experts and representatives of the collaborating medical societies and patient organizations.ResultsThe revised guidelines for the surgical treatment of benign thyroid diseases include recommendations regarding the preoperative assessment necessary to determine when surgery is indicated. Recommendations regarding the extent of resection, surgical techniques, and perioperative management are also given in order to optimize patient outcomes.ConclusionsEvidence-based recommendations for the surgical treatment of benign thyroid diseases have been created to aid the surgeon and to support optimal patient care, based on current knowledge. These recommendations comply with the Association of the Scientific Medical Societies in Germany requirements for S2k guidelines.

German Association of Endocrine Surgeons practice guideline for the surgical management of malignant thyroid tumors

IntroductionOver the past years, the incidence of thyroid cancer has surged not only in Germany but also in other countries of the Western hemisphere. This surge was first and foremost due to an increase of prognostically favorable (“low risk”) papillary thyroid microcarcinomas, for which limited surgical procedures are often sufficient without loss of oncological benefit. These developments called for an update of the previous practice guideline to detail the surgical treatment options that are available for the various disease entities and tumor stages.MethodsThe present German Association of Endocrine Surgeons practice guideline was developed on the basis of clinical evidence considering current national and international treatment recommendations through a formal expert consensus process in collaboration with the German Societies of General and Visceral Surgery, Endocrinology, Nuclear Medicine, Pathology, Radiooncology, Oncological Hematology, and a German thyroid cancer patient support organization.ResultsThe practice guideline for the surgical management of malignant thyroid tumors includes recommendations regarding preoperative workup; classification of locoregional nodes and terminology of surgical procedures; frequency, clinical, and histopathological features of occult and clinically apparent papillary, follicular, poorly differentiated, undifferentiated, and sporadic and hereditary medullary thyroid cancers, thyroid lymphoma and thyroid metastases from primaries outside the thyroid gland; extent of thyroidectomy; extent of lymph node dissection; aerodigestive tract resection; postoperative follow-up and surgery for recurrence and distant metastases.ConclusionThese evidence-based recommendations for surgical therapy reflect various “treatment corridors” that are best discussed within multidisciplinary teams and the patient considering tumor type, stage, progression, and inherent surgical risk.

Risk factors for postoperative bleeding after thyroid surgery

Postoperative bleeding after thyroid surgery is a feared and life‐threatening complication. The aim of the study was to identify risk factors for postoperative bleeding, with special emphasis on the impact of the individual surgeon and the time to diagnosis of the complication.

Hashimoto's Thyroiditis Affects Symptom Load and Quality of Life Unrelated to Hypothyroidism: A Prospective Case–Control Study in Women Undergoing Thyroidectomy for Benign Goiter

BACKGROUND Hashimotos thyroiditis (HT) is a common disease, and is the most prevalent cause of hypothyroidism. Symptoms and diseases associated with HT are considered to be caused by hypothyroidism. We hypothesized that higher antithyroperoxidase (anti-TPO) antibody levels would be associated with an increased symptom load and a decreased quality of life in a female euthyroid patient collective. METHODS In a prospective cohort study 426 consecutive euthyroid female patients undergoing thyroid surgery for benign thyroid disease were included. Main outcome measures were preoperative anti-TPO levels, a symptom questionnaire and the SF-36 questionnaire, and lymphocytic infiltration of the thyroid tissue as evaluated by histology. RESULTS Histology revealed HT in 28/426 (6.6%) subjects. To maximize the sum of the predictive values, a cut-off point for anti-TPO of 121.0 IU/mL was calculated (sensitivity 93.3% [95% confidence interval: 77.9%-99.0%]; specificity 94.7% [95% confidence interval: 92.0%-96.7%]) to predict the presence of histological signs of HT. The mean number of reported symptoms was significantly higher in patients with anti-TPO levels >121.0 IU/mL than in the other group (6.7 ± 2.5 vs. 4.1 ± 2.8; p < 0.001). There were no differences in preoperative thyroid-stimulating hormone levels (1.7 ± 1.3 vs. 1.5 ± 1.4 μU/mL, respectively; p = 0.155). Chronic fatigue, dry hair, chronic irritability, chronic nervousness, a history of breast cancer and early miscarriage, and lower quality-of-life levels were significantly associated with anti-TPO levels exceeding the cut-off point (p < 0.05). CONCLUSIONS Women with HT suffer from a high symptom load. Hypothyroidism is only a contributing factor to the development of associated conditions.

A new vagal anchor electrode for real-time monitoring of the recurrent laryngeal nerve

BACKGROUND Despite conventional neuromonitoring, the recurrent laryngeal nerve (RLN) is still at risk for damage during thyroid surgery. The feasibility of continuous RLN monitoring by vagal nerve (VN) stimulation with a new anchor electrode should be shown, and electromyographic signal alterations of stressed RLN were analyzed to be alerted to imminent nerve failure whereby the nerve damage becomes reversible. METHODS VN stimulation was achieved in 23 pigs. Sensed signals were analyzed and stored as real-time audio/video feedback EMG system. RLN was stressed by mechanical and thermal injury; signal alterations were evaluated. RESULTS VNs were successfully real-time stimulated by using the anchor electrode. No complications or side effects during stimulation were detected. RLN injury led to an alteration of signal amplitude and latency period but signal restitution after injury. CONCLUSIONS Real-time monitoring of the RLN is technically feasible to perceive imminent nerve failure. The anchor electrode was safely and easy to handle. Its implementation is being tested in an ongoing clinical trial.

Kinetics of serum parathyroid hormone during and after thyroid surgery.

Hypocalcaemia after thyroidectomy is thought to result from surgical damage to the parathyroid glands. This study analysed postoperative outcomes related to perioperative parathyroid hormone (PTH) levels.

Evolution of Nerve Injury with Unexpected EMG Signal Recovery in Thyroid Surgery Using Continuous Intraoperative Neuromonitoring

BackgroundIntermittent intraoperative neuromonitoring cannot prevent preparative surgical damage or predict imminent recurrent laryngeal nerve (RLN) damage with subsequent development of loss of electromyogram (EMG) signal during thyroid surgery. In case the nerve is stressed, i.e., from traction near the ligament of Berry, the nerve injury is only detected after it has occurred, not allowing the surgeon to correct the mechanical maneuver and salvage nerve function intraoperatively.MethodsThe unusual clinical scenario of sacrifice of a tumor-infiltrated RLN was used to study real-time evolution of RLN injury caused by mechanical distention. The ipsilateral vagus nerve (VN) was continuously stimulated with a new stimulation probe, and changes in EMG response were correlated with the varying levels of stretch and traction.ResultsMechanical traction induced an intermittent depression of EMG amplitudes as a sign of impaired propagation of axon potentials or synaptic transmission. Prolonged mechanical stress caused a long-lasting depression of EMG response. When the mechanical distention was relieved, neurotransmission was gradually restored, with reappearance of singular muscle depolarization of full magnitude interspersed between the barely detectable deflections in the EMG recording. These responses of full amplitude appeared with increasing frequency, until the regular continuous EMG pattern was completely restored.ConclusionsOnly continuous VN stimulation serves to detect early changes in EMG response that indicate imminent danger to RLN functional integrity and alerts the surgeon to immediately correctable surgical actions, thus possibly preventing nerve damage or transforming damage into a reversible event.

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.