Management von Nachblutungen nach Schilddrüsenoperationen

A diagnostic phase III/IV seamless design to investigate the diagnostic accuracy and clinical effectiveness using the example of HEDOS and HEDOS II

The development process of medical devices can be streamlined by combining different study phases. Here, for a diagnostic medical device, we present the combination of confirmation of diagnostic accuracy (phase III) and evaluation of clinical effectiveness regarding patient-relevant endpoints (phase IV) using a seamless design. This approach is used in the Thyroid HEmorrhage DetectOr Study (HEDOS & HEDOS II) investigating a post-operative hemorrhage detector named ISAR-M THYRO® in patients after thyroid surgery. Data from the phase III trial are reused as external controls in the control group of the phase IV trial. An unblinded interim analysis is planned between the two study stages which includes a recalculation of the sample size for the phase IV part after completion of the first stage of the seamless design. The study concept presented here is the first seamless design proposed in the field of diagnostic studies. Hence, the aim of this work is to emphasize the statistical methodology as well as feasibility of the proposed design in relation to the planning and implementation of the seamless design. Seamless designs can accelerate the overall trial duration and increase its efficiency in terms of sample size and recruitment. However, careful planning addressing numerous methodological and procedural challenges is necessary for successful implementation as well as agreement with regulatory bodies.

Efficacy of four different hemostatic agents in thyroid surgery in reducing the amount of post-operative fluid collection

PURPOSES

Postoperative bleeding remains a life-threatening complication in thyroid surgery. The aim was to assess the efficacy of four different hemostatic agents, Collagen-Fibrinogen-Thrombin Patch (CFTP) in two sizes (3 × 2.5 cm and 9.5 × 4.8 cm), polysaccharide particles (1 g) and Cellulose Gauze (2.5 × 5 cm) on postoperative drainage volume (DV) compared to a control group.

METHODS

We included from October 2007 until Mai 2011, 150 patients (30 per group) for this monocentric, retrospective case-controlled study. Patients were scheduled for a hemithyroidectomy or thyroidectomy. The primary endpoint was the postoperative DV within the first 24 h, secondary the incidence of adverse events.

RESULTS

There were no difference in demographic parameters. The mean DV (± SD) was 51.15 (± 36.86) ml in the control, 50.65 (± 42.79) ml in small (3 × 2.5 cm), 25.38 (± 23.99) ml in large CFTP (9.5 × 4.8 cm), 53.11 (± 39.48) ml in the polysaccharide particles and 48.94 (± 30.59) ml in the cellulose gauze group. DV was significantly reduced with the large CFTP (p < 0.05) compared to all other groups. There were no adverse events.

CONCLUSIONS

We were able to demonstrate a significant reduction in the DV for the large CFTP group compared to the other collectives. Although this as being associated with not inconsiderable costs and we would only recommend its use for high-risk patients only.

Neck Circumference Measurement for Surveillance and Early Detection of Hemorrhage After Thyroidectomy: A Diagnostic Accuracy Study

Importance

Postthyroidectomy hemorrhage is a potentially life-threatening complication with no reliable noninvasive method of early detection.

Objective

To evaluate the diagnostic accuracy of neck circumference measurement for early detection of postoperative hemorrhage after thyroidectomy.

Design, Setting, and Participants

This diagnostic accuracy study at an academic teaching hospital used a prospective cohort of patients undergoing thyroid surgery from November 1, 2015, to January 31, 2018 (group 1), and a retrospective cohort of patients undergoing the same surgery from January 1, 2020, to September 30, 2021 (group 2). We performed repeated perioperative neck circumference measurements to evaluate the association of increased neck circumference with postthyroidectomy hemorrhage among patients at risk for hemorrhage.

Main Outcomes and Measures

The primary end point was the diagnostic value of neck circumference measurement for detection of postthyroidectomy hemorrhage. Additionally, data on demographic information and risk factors for postthyroidectomy hemorrhage were examined. Data analyses were performed from November 1, 2021, to January 5, 2022.

Results

The prospective cohort (group 1) comprised 60 patients (45 [75%] women) with a mean (SD) age of 52.2 (13.5) years; those who experienced a postthyroidectomy hemorrhage had a mean (SD) age of 57.4 (9.0) years. The retrospective cohort (group 2) comprised 353 patients (258 [73%] women) with a mean (SD) age of 55.3 (14.1) years; patients who experienced a postthyroidectomy hemorrhage had a mean (SD) age of 62.2 (10.0) years. In group 1, postoperative neck circumference increased by a median (range) of 5.0 (4.0 to 7.0) cm in patients with hemorrhage, and only 1.0 (-2.5 to 4.0) cm in patients with no postoperative bleeding (difference in the medians, 4.0 cm [95% CI, 3.0 to 5.5 cm]; effect size, 3.74 [95% CI, 2.6 to 4.9]). Defining a 7% or greater increase in neck circumference as the cutoff value for detecting postthyroidectomy hemorrhage showed a diagnostic sensitivity and specificity of 1.0 (95% CI, 0.48 to 1.0) and 0.86 (95% CI, 0.71 to 0.92), respectively. The retrospective validation also showed a difference in median (range) increase of postoperative neck circumference between patients with hemorrhage and those without-3.0 (0 to 6.0) cm vs 0.0 (-6.0 to 5.0) cm (difference in medians, 3.8 cm [95% CI, 3.0 to 4.9]; effect size, 1.63 [95% CI, 0.96 to 2.3]). Considering 12 false-positive and 332 correct-negative results, the diagnostic tool showed a sensitivity of 0.89 (95% CI, 0.51 to 0.99) and a specificity of 0.97 (95% CI, 0.94 to 0.98).

Conclusions and Relevance

The findings of this diagnostic accuracy study suggest that neck circumference measurement is a feasible and easy-to-use diagnostic tool for routine clinical care to detect postthyroidectomy hemorrhage. A 7% or greater increase over the postoperative baseline neck circumference seems to be a reliable threshold for detecting postthyroidectomy hemorrhage. Neck circumference measurement should be used in combination with surveillance of clinical signs and symptoms.

A cervical compartment syndrome impairs cerebral circulation in post-thyroidectomy hemorrhage: data from an animal model

BACKGROUND

Post thyroidectomy hemorrhage is a potentially life-threatening complication. As the mechanism leading to hypoxemic brain damage and death is still unknown, our aim was to examine the underlaying pathophysiology in an animal model.

METHODS

A series of experiments was performed in our established model for post thyroidectomy hemorrhage in 6 pigs. First, post thyroidectomy hemorrhage was simulated with an artificial increase of cervical compartment pressure. Second, spontaneous bleeding into the cervical compartment was initiated. Primary outcome measure is the correlation between cerebral oxygenation and cervical compartment pressure.

RESULTS

With an increase in cervical compartment pressure apnea could be detected in all experiments. A significant 24.2% (9.5-34.4%) decrease of cerebral oxygenation at time of apnea (47.0%; 38.0-65.0%) compared to baseline values (63.5%; 56.0-74.0%; P=0.043) occurred due increase of cervical compartment pressure concurrent with an impaired cerebral perfusion. Apnea occurred about 200 sec after a 10% decrease of cerebral oxygenation, but 35 sec before a 10% decrease of peripheral oxygenation. Spontaneous bleeding into the cervical compartment causes an increase of cervical compartment pressure reaching levels of the mean arterial blood pressure 56.0 (35.0-72.0) mmHg.

CONCLUSIONS

Peripheral hypoxemia occurs with relevant delay in time after decrease of cerebral perfusion and cerebral hypoxemia, therefore cerebral hypoxemia seems to be causal for a central apnea. With this evidence of impaired cerebral perfusion and cerebral hypoxemia due to an increased cervical compartment pressure we can disprove the historic theory of tracheal collapse due to a compressive hematoma in post thyroidectomy hemorrhage. A cervical compartment syndrome seems to be causal, not only for brain hypoxemia but also an additional laryngo-pharyngeal mucosal edema.

Results of a randomised controlled trial between an ORC collagen hemostatic agent and a carrier-bound fibrin sealant

INTRODUCTION

Despite ongoing optimisation of surgical techniques, hemostasis continues to be a fundamental challenge in many operations today. This randomised controlled trial compared the efficacy of a new hemostatic agent made of oxidised regenerated cellulose and collagen (ORC-Coll) with that of a conventional carrier-bound fibrin sealant (CBFS).

METHODS

Hemostasis was investigated representatively in the case of post-thyroidectomy bleeding from the resection surface. To demonstrate that ORC-Coll (mediCipio® A) has at least the same hemostatic efficacy as CBFS (Tachosil®), the volume of drainage fluid at the time of drain removal was used as the primary endpoint in a non-inferiority test with a significance level of 5%. The secondary endpoints included number and size of hemostatic agents required, adhesion of the hemostatic agent to the bleeding surface, intraoperative hemostatic effect, duration of drainage and adverse events during a six-month follow-up period.

RESULTS

A total of 150 patients (ORC-Coll: 75; CBFS: 75) were included. After operation, total volume of drainage fluid was 68.20±44.56mL in the ORC group and 68.21±40.20mL in the CBFS group. The non-inferiority of ORC-Coll compared to CBFS with regard to hemostatic efficacy was shown at a significance level of 5%. The results demonstrated effectiveness in achieving hemostasis without adverse events.

CONCLUSIONS

ORC-Coll is an effective hemostatic agent and barrier sealant without blood components, which ensures reliable prevention of intra- and postoperative bleeding. With use of the new technique, any risks associated with the use of human blood components are a priori eliminated.

Volume, outcomes, and quality standards in thyroid surgery: an evidence-based analysis-European Society of Endocrine Surgeons (ESES) positional statement

INTRODUCTION

Continuous efforts in surgical speciality aim to improve outcome. Therefore, correlation of volume and outcome, developing subspecialization, and identification of reliable parameters to identify and measure quality in surgery gain increasing attention in the surgical community as well as in public health care systems, and by health care providers. The need to investigate these correlations in the area of endocrine surgery was identified by ESES, and thyroid surgery was chosen for this analysis of the prevalent literature with regard to outcome and volume.

MATERIALS AND METHODS

A literature search that is detailed below about correlation between volume and outcome in thyroid surgery was performed and assessed from an evidence-based perspective. Following presentation and live data discussion, a revised final positional statement was presented and consented by the ESES assembly.

RESULTS

There is a lack of prospective randomized controlled studies for all items representing quality parameters of thyroid surgery using uniform definitions. Therefore, evidence levels are low and recommendation grades are based mainly on expert and peer evaluation of the prevalent data.

CONCLUSION

In thyroid surgery a volume and outcome relationship exists with respect to the prevalence of complications. Besides volume, cumulative experience is expected to improve outcomes. In accordance with global data, a case load of < 25 thyroidectomies per surgeon per year appears to identify a low-volume surgeon, while > 50 thyroidectomies per surgeon per year identify a high-volume surgeon. A center with a case load of > 100 thyroidectomies per year is considered high-volume. Thyroid cancer and autoimmune thyroid disease predict an increased risk of surgical morbidity and should be operated by high-volume surgeons. Oncological results of thyroid cancer surgery are significantly better when performed by high-volume surgeons.

[Update of the S2k guidelines : Surgical treatment of benign thyroid diseases]

Thyroid resections represent one of the most common operations with 76,140 interventions in the year 2016 in Germany (source Destatis). These are predominantly benign thyroid gland diseases. Recommendations for the operative treatment of benign thyroid diseases were last published by the CAEK in 2010 as S2k guidelines (Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften e.V. [AWMF] 003/002) against the background of increasingly more radical resection procedures. Hemithyroidectomy and thyroidectomy are routinely performed for benign thyroid disease in practice. The operation-specific risks show a clear increase with the extent of the resection. Therefore, weighing-up of the risk-indications ratio between unilateral lobectomy or thyroidectomy necessitates an independent evaluation of the indications for both sides. This principle in particular has been used to update the guidelines. In addition, the previously published recommendations of the CAEK for correct execution and consequences of intraoperative neuromonitoring were included into the guidelines, which in particular serve the aim to avoid bilateral recurrent laryngeal nerve paralysis. Moreover, the recommendations for the treatment of postoperative complications, such as hypoparathyroidism and postoperative infections were revised. The updated guidelines therefore represent the current state of the science as well as the resulting surgical practice.

New insights into the pathophysiology of postoperative hemorrhage in thyroid surgery: An experimental study in a porcine model

BACKGROUND

Postoperative cervical hemorrhage is a rare but life-threatening complication that can cause severe morbidity. Different mechanisms leading to asphyxia have been described based only on clinical observation.

METHODS

We performed a series of in vivo animal studies simulating post-thyroidectomy hemorrhage and its effect on respiratory drive. Three series of tests were carried out in 12 German domestic pigs under general anesthesia. The pigs were breathing spontaneously with secured airways. An additional series using functional magnetic resonance imaging of the pigs' brainstem was also conducted.

RESULTS

The first experimental series carried out on 2 animals revealed an obvious difference between the effects of cervical hemorrhage and external bleeding with development of hemorrhagic shock. An experimental setting for the repeated simulation of cervical hemorrhage was established. A pressure-dependent mechanism was discovered that led to apnea in every animal despite the secured airway. In 8 of 10 animals, relief of cervical pressure led to complete respiratory recovery. The test was repeated up to 6 times per pig. Apnea was induced in 25 of 25 test procedures (100%) and was followed by respiratory recovery in 22 of 25 tests (88%). The threshold pressure at which the respiratory rate started to decrease was 47 ± 14 Torr when blood was used to increase the cervical compartment pressure. When silicone oil was used in a further experimental series, the threshold pressure was similar at 44 ± 21 Torr. The cervical compartment pressure needed to induce apnea was 74 ± 18 Torr using blood and 74 ± 39 Torr using silicone oil, both of which exceeded the mean arterial pressure by 28 Torr during apnea. Functional magnetic resonance imaging revealed a decrease in brainstem activity during phases of increased cervical compartment pressure, which suggests a possible role for cerebral vascular perfusion.

CONCLUSION

Respiratory drive can be suppressed by increased pressure in the cervical compartment, possibly because of a pressure-dependent impairment in cerebral perfusion through a form of cervical compartment phenomenon or, less likely, a pressure-dependent reflex (nervous) mechanism.

Compartment Pressure Monitoring After Thyroid Surgery: A Possible Method to Detect a Rebleeding

BACKGROUND

Postoperative rebleeding after thyroid surgery is a rare but a serious complication. The aim of this study was to ascertain the extent to which postoperative pressure could be used as detector for rebleeding after thyroid surgery.

METHODS

Thirty-two patients with thyroidectomy or hemithyroidectomy were considered prospectively. In the course of surgery, a pressure microsensor (3PN Probe Spiegelberg) was implanted into the postoperative cavity and data were collected for special activities and stress situations over the first 48 h postoperatively. Additional endpoint was the influence of drains on the determined values.

RESULTS

The overall mean pressure (MP) at rest on both postoperative days for all patients with and without drain was 0.36 ± 2.84 mmHg (range -6.7 to 6.7). The MP in all activity and stress situations on the first day was with 0.23 ± 3.71 mmHg, and on the second day, the MP was 1.33 ± 4.50. 92.13% of our values were below 7 mmHg. One patient had a hemorrhage. The pressure increases continuously up to 36 mmHg, before the patient was transferred to the operating theater.

CONCLUSIONS

This is the first pilot study to consider continuous pressure measurement to be a potential tool for early detection of a postoperative rebleeding in thyroid surgery. In the strictest sense, postoperative intra-cervical pressure at rest ranges from subatmospheric to 7 mmHg. The elevation of pressure in case of a rebleeding up to 36 mmHg differs dramatically from normal postoperative pressure. The collected data will warrant further validation to be able to recommend threshold values for an early treatment decisions in rebleeding.

[Complications after thyroid gland operations in Germany : A routine data analysis of 66,902 AOK patients]

BACKGROUND

Routine data from hospitals in the public healthcare system allow the analysis of large patient datasets without generating additional documentation efforts for hospitals. This study reports the frequencies of postoperative complications after thyroid surgery based on routine nationwide data. Moreover, volume-outcome relationships were investigated.

MATERIAL AND METHODS

Nationwide routine data from insured patients of the Local Health Insurance Fund (AOK) who underwent thyroid surgery between 2008 and 2010 were analyzed. Complications were determined based on indicators for permanent vocal cord palsy, re-bleeding with re-operations and wound infections with specific treatment. The effect of hospital volumes (volume quintiles) on the indicators was determined by multivariate logistic regression.

RESULTS

A total of 66,902 thyroid gland operations were identified. The overall frequency of permanent vocal cord palsy was 1.5 %, re-bleeding 1.8 % and wound infections 0.4 %. In the four lowest case volume categories the risk of permanent vocal cord palsy was significantly higher compared to the highest case volume hospitals (odds ratio 1.5, 1.7, 1.7 and 2.2, respectively).

CONCLUSION

This study represents the reality of healthcare for thyroid surgery in Germany. Additionally, it was determined that the risk for permanent vocal cord palsy after thyroid gland operations decreased with increasing case volumes of hospitals.