Multi-functional voltage and current based enhancement of power quality in grid-connected microgrids considering harmonics

The introduction of a renewable energy source (RES) based multi-functional grid-tied inverter (MFGTI) stands as a favorable remedy for addressing power quality concerns within distributed generation (DG) systems and microgrids. Nonetheless, the effectiveness of a traditional MFGTI will be restricted in addressing power quality issues based on voltage. The presented research proposes a novel structure for MFGTI to enhance power quality concerns associated with voltage, current, and harmonic distortions resulting from both grid and loads. Based on this strategy, the introduced MFGTI can be linked with the grid by bidirectional switches either in a parallel or series. This feature provides various operational conditions in response to diverse disruptions in the grid. To effectively adjust the voltage, current and voltage reduction are determined through mathematical analysis, considering both the grid conditions and the load requirements. Furthermore, this strategy offers different compensation strategies, control schemes, and transition modes in the MFGTI. The major disturbances such as unbalanced and balanced voltage swell/sag, harmonics, and interruption are compensated. The shunt compensation controller is based on a second order sequence filter (SOSF) to provide the load current active component. A damping PI regulator based series compensation controller is presented for the voltage swell/sag reduction. Moreover, a new three level hierarchical control is proposed in which a droop control for compensating the interruption and a decouple dual synchronous reference frame (DDSRF) for compensating the unbalanced voltage sag/swell are utilized. The simulations in the MATLAB/SIMULINK show that using the proposed compensation strategies, the proposed MFGTI can compensate effectively the different disturbances through changing the transition states by the proposed algorithm based bidirectional switches.

Comparing adverse events associated with LigaSure and Harmonic devices in head and neck surgery

OBJECTIVE

To characterize adverse events, provide a safety profile, and understand patient outcomes after complications arising from LigaSure and Harmonic use in the head and neck region.

METHODS

Retrospective analysis of adverse events from the Manufacturer and User Facility Device Experience (MAUDE) between January 2013 and 2023.

RESULTS

A total of 158 LigaSure and 159 Harmonic events were extracted. There were significantly more reports of Harmonic device overheating (6.9% vs. 0.6%, p = 0.003) and spontaneous self-activation (4.4% vs. 0%, p = 0.032). Although intra-operative and post-operative complications were similar among both groups, there were significantly more intra-operative bleeding events for LigaSure as compared to Harmonic (8.2% vs. 0.0%, p = 0.001).

CONCLUSION

Understanding technical complications and adverse events attributable to LigaSure and Harmonic devices enables the development of clinically relevant risk mitigation strategies. Surgeons should avoid improper use by remaining vigilant of device functionality and temperature changes.

Which combination cause less inflammatory response during laparoscopic hysterectomy? Ligasure plus monopolar cautery or harmonic plus bipolar cautery?

Objective

We aimed to compare the inflammatory response with alterations in hemogram parameters, in patients who underwent laparoscopic hysterectomy and bilateral salpingo-oophorectomy for benign gynecologic conditions with ligasure plus monopolar cautery or harmonic plus conventional bipolar cautery.

Methods

Patients who underwent Laparoscopic hysterectomy with bilateral salpingo-oophorectomy between January 2017 and January 2022 for benign gynecologic pathology were identified. Patients were divided into two group, according to instruments used during surgery. Instruments were used according to surgeons preference. Preoperative and postoperative in the first 24 hours hematocrit (HCT), WBC, trombocyt, neutrophil- lymphocyte (NLR), platelet-lymphocyte (PLR) ratio, mean platelet volume- lymphocyte ratio (MPVLR) and red cell distribution width- platelet ratio (RPR) values were compared.

Results

During study period, a total of 462 patients underwent hysterectomy for benign gynecologic pathology. After exclusion, 212 patients were included in the study. İn the study group, 147 patients were operated with ligasure plus monopolar electrocauter and 65 with harmonic scalpel plus bipolar electrocautery. İn the postoperative period, regardless of the procedure, WBC and RPR count increase, hematocrit and trombocyt decrease in both group but the inflammatory markers lymphocyte count, neutrophyl, NLR, PLR and MPVLR count changed less in the harmonic plus bipolar cautery group which shows less inflamatuar response in this group.

Conclusions

Ligasure plus monopolar cautery group compared with harmonic plus bipolar cautery group cause more inflammatory changes in complete blood count values. However, further studies are needed to show whether these changes in laboratory findings affect clinical situations.

An umbrella review of the surgical performance of Harmonic ultrasonic devices and impact on patient outcomes

BACKGROUND

For thirty years, the Harmonic scalpel has been used for precise dissection, sealing and transection. There are numerous meta-analyses on individual surgical procedures with Harmonic, but no overarching review covering all the areas. This umbrella review seeks to summarize the clinical results from the use of Harmonic across surgical fields and broadly quantify its effects on patient outcomes.

METHODS

MEDLINE, EMBASE, and Cochrane Databases were searched for meta-analyses (MAs) of randomized controlled trials (RCTs) comparing Harmonic devices to conventional techniques or advanced bipolar (ABP) devices. For each procedure type, the most comprehensive MAs were evaluated. RCTs not already analysed in a MA were also included. Operating time, length of stay, intraoperative blood loss, drainage volume, pain, and overall complications were evaluated, and the methodological quality and certainty of evidence were assessed.

RESULTS

Twenty-four systematic literature reviews were identified on colectomy, hemorrhoidectomy, gastrectomy, mastectomy, flap harvesting, cholecystectomy, thyroidectomy, tonsillectomy, and neck dissection. There were also 83 RCTs included. In every MA evaluated, Harmonic devices were associated with either statistically significant or numerical improvements in every outcome compared with conventional techniques; most MAs reported a reduction in operating time of ≥ 25 min. Harmonic versus ABP device MAs in colectomy and thyroidectomy showed no significant differences in outcomes.

CONCLUSION

Across surgical procedures, Harmonic devices demonstrated improved patient outcomes for operating time, length of stay, intraoperative bleeding, drainage volume, pain, and overall complications compared to conventional techniques. Additional studies are required to assess differences between Harmonic and ABP devices.

Electrocautery, Harmonic, and Thunderbeat Instruments in Parotid Surgery: A Retrospective Comparative Study

The aim of this retrospective study has been to compare the surgical outcomes of patients undergoing superficial parotidectomy with three different instruments: bipolar electrocautery, ultrasound, and mixed energy instruments. The clinical records of 102 patients who had undergone superficial parotidectomy for benign tumors between January 2016 and April 2022 were considered. Based on the tool used during the surgery, the patients were divided into three study groups: classic electrocautery hemostasis group (CH group), ultrasonic instrument group (HA group), and combined energy instrument group (TB group). The duration of surgery, the total post-operative drainage volume, and the intra-operative blood loss were significantly higher in the CH group compared to the HA and the TB group, while the differences were not significant between the latter two groups. Facial nerve weakness was detected in 45.9% of the CH group, 12.5% of the HA group, and 21.2% of the TB group. The rate of facial nerve dysfunction in the CH group was significantly higher than in the HA group (0.011). In the patients who experienced post-operative facial nerve dysfunction, the recovery time was significantly shorter in the HA group compared to the CH and the TB group. The HA and TB groups have demonstrated comparable and significantly better surgical outcomes than bipolar electrocautery. Ultrasound instruments have been shown to cause, in comparison with the other techniques, a lower rate of temporary facial nerve dysfunction and, if this is present, lead to a faster spontaneous recovery time.

Harmonics, evolutionary generators, DANCE, and HEAR-functional dimensions

Evolution of the major kingdoms of life has spanned over the last 4 billion years on Earth. Studies of the process comprise different fields of study with alternative perspectives. This paper focuses on mathematic unification of the subject area; enriching an engineering based structure to advance our understanding of pathways which lead to distinct constructs in life, furthering geographic bordering processes with biological context. Application of logistic regression requires partitioning of variance within cellular and molecular systems; use of higher mathematic technique (multi-objective genetic algorithm) generates variance within the different scales of evolution, the result of which is analogous with the Fisher equation model of gene distribution within populations. Laboratory and field studies were integrated to illustrate emergence in evolutionary processes in the terrestrial/soil environment. Nematological field and laboratory trials validate the existence of triangular relationships within biological communities; further harmonic constants between interacting species may be found with emergent consequence. We distinguish different strategical groupings in the soil community, with the core groupings recognized with Meloidogyne spp. illustrating positive (emergent) growth; Radopholus similis (neutral growth), and Helicotylenchus pseudorobustus (negative growth). The patterns of emergent systems are shown in the extremes of Morocco's dynamic soil environment. Fuzzy classification methods: Mamdani, Takugi-Sugeno-Kang; additional novel DANCE (Differential Algorithmic Network Centered Emergence) and functional expressions HEAR (Harmonic Evolutionary Algorithmic Resilience), are recommended to give a basis for development of constructs covering different categories of life.

The role of LigaSure™ and Harmonic Scalpel in the preservation of recurrent laryngeal nerve during thyroidectomy

INTRODUCTION

Transient or permanent damage to the recurrent laryngeal nerve (RLN) during thyroidectomy is of paramount importance for patient quality of life. The aim of this study is to systematically review the literature concerning the role of the most popular energy-based vessel-sealing devices (LigaSure™ (LS) and Harmonic Scalpel (HS)) in preservation of the RLN during thyroidectomy. The safety and inferiority or superiority of LS and HS compared with conventional haemostatic techniques are highlighted.

METHODS

A systematic search of the literature was performed. Clinical trials, prospective and retrospective studies that significantly compared the use of LS and HS with conventional haemostasis regarding the postoperative incidence of RLN palsy were included.

FINDINGS

The search resulted in 43 studies, including 17,953 patients treated using energy-based devices or conventional haemostatic methods. Concerning the incidence of RLN palsy, 40 studies showed no significant difference between the energy-based device and conventional groups, whereas two studies demonstrated a significant superiority in performance for LS and HS compared with conventional haemostasis. Only one study exhibited significant inferiority of LS and HS compared with conventional methods. No statistical relationship was observed between energy-based devices and conventional techniques regarding permanent damage to the RLN.

CONCLUSION

The performance of both LS and HS shows no inferiority compared with conventional haemostatic techniques, regarding damage to the laryngeal nerve. Further well-designed studies are needed to investigate their potential benefit in preservation of the RLN.

Period-oriented multi-hierarchy deconvolution and its application for bearing fault diagnosis

Deconvolution methods have been proven to be effective tools to extract excitation sources from the noisy measured signal. However, its application is confined by the extraction of incomplete information. To tackle this problem, a new deconvolution method, named period-oriented multi-hierarchy deconvolution (POMHD) is proposed in this paper. Various filters are designed adaptively by the iterative algorithm to update the filter coefficient using the harmonic-to-noise ratio as the deconvolution orientation. Additionally, a novel index, called normalized proportion of harmonics, is proposed as the evaluation criteria for the fault feature. Based on upon, a harmonics proportion diagram is constructed for the diagnostic decisions. The new deconvolution method overcomes the disadvantages of the traditional methods. More importantly, without an accurate fault period as the prior knowledge, the proposed POMHD can simultaneously extract multiple latent fault components by using the adaptive filter and intuitively present different fault information in one diagram. Finally, the simulated and experimental data which includes the signals collected from bearings with both single faults and compound faults is used to evaluate the new method. The results validate the feasibility and robustness of the proposed POMHD.

Evaluation of ultrasonic axillary dissection in preservation of intercostobrachial nerve and lymphatic sealing in breast cancer patients: Randomized controlled trial

BACKGROUND

Electrocautery has been shown to be associated with excessive serous drainage which may lead to many complications in patients with breast cancer needing dissection of the axillary lymph nodes. The Harmonic Focus could outperform electrocautery in dissection of axillary lymph nodes, resulting in shortening of the operative times and minimize postoperative complications. This study aims to compare the mean axillary drain production and the axillary numbness frequency in axillary lymph node dissection (ANLD) during Modified Radical Mastectomy (MRM) and breast conservative surgery (BCS) between the use of harmonics scalpel and electrocautery.

METHODS

This study includes 40 patients presented with early breast cancer (T1 and T2) underwent BCS or MRM in general surgery department, Faculty of Medicine, Benha University Hospital during the period from January 2017 to September 2019. The patients randomly assigned into 2 groups; group A: subjected to ANLD using Harmonic Focus tool and group B: subjected to ANLD using electrocautery. Operative time, total drainage volume, blood loss, duration of the drain and frequency of axillary numbness were recorded.

RESULTS

This study shows that using Harmonic in axillary dissection considerably reduced operating time, total drainage volume, blood loss, days of hospital stays and reduced axillary numbness level in comparison to conventional electrocautery.

CONCLUSION

Compared to the normal electrocautery, the harmonic focus dissection has major advantages in lowering postoperative drainage, blood loss intra-operative and lower incidence of axillary numbness in breast cancer axillary dissection, without affecting operating time.

Harmonic Scalpel Versus Coblation Tonsillectomy A Comparative Study

Tonsillectomy is an age old procedure in ENT practice. Though traditional dissection method is gold standard, we surgeons are trying different techniques like electrocautery, coblation, harmonic scalpel (HS) mainly to improve surgical convenience, to decrease operative time, post operative pain, intra and post operative bleeding and fast return to normal life. In this particular study we are comparing coblation and HS as surgical tool in tonsillectomy. It is a prospective double-blind randomized controlled trial where information was compared between two groups of coblation and HS tonsillectomy. A total number of 128 patients were compared over operation time, intra-operative blood loss, postoperative pain, time needed to regain the normal diet and activity and postoperative haemorrhage. We found statistically significant differences in operation time (p < 0.001) and intra operative blood loss (p < 0.001). Secondary haemorrhage rate was far better in HS (1.5%) group compared to coblation (7.8%). Whereas postoperative pain, time needed to go back to the normal diet and activity were better in HS group but the difference is not significant. This study revealed a significantly less operative time and intra-operative and post operative blood loss in harmonic scalpel tonsillectomy in comparison with coblation method. These findings addressed HS tonsillectomy as an advanced method.

A systematic review of the voice-tagging hypothesis of speech-in-noise perception

The voice-tagging hypothesis claims that individuals who better represent pitch information in a speaker's voice, as measured with the frequency following response (FFR), will be better at speech-in-noise perception. The hypothesis has been provided to explain how music training might improve speech-in-noise perception. This paper reviews studies that are relevant to the voice-tagging hypothesis, including studies on musicians and nonmusicians. Most studies on musicians show greater f0 amplitude compared to controls. Most studies on nonmusicians do not show group differences in f0 amplitude. Across all studies reviewed, f0 amplitude does not consistently predict accuracy in speech-in-noise perception. The evidence suggests that music training does not improve speech-in-noise perception via enhanced subcortical representation of the f0.

Nonlinearities in the flicker electroretinogram: A tool for studying retinal dysfunction applied to early-stage diabetic retinopathy

The flicker electroretinogram (ERG) is typically analyzed in terms of peak-to-trough amplitude and implicit time. However, additional important information may be captured by spectral-domain analysis of the ERG harmonics (responses that occur at multiples of the stimulus frequency). This study describes an approach to analyze the harmonic components of the flicker ERG and its application to patients who have early-stage non-proliferative diabetic retinopathy (NPDR). Of particular interest were the sub-harmonic components occurring at 1.5x and 2.5x the stimulus frequency that produce cycle-to-cycle variation in amplitude termed "period doubling." Twenty visually-normal subjects, 20 diabetic subjects who have no clinically-apparent retinopathy (NDR), and 20 diabetic subjects who have mild NPDR participated. ERGs were recorded in response to sinusoidal flicker (27-63 Hz) and Fourier analysis was performed to extract fundamental and harmonic response amplitudes. Linear quantile mixed models (LQMMs) were used to compare the amplitude of the response components among the three subject groups. Results indicated that the maximum sub-harmonic amplitude occurred in the stimulus frequency range of 33-38 Hz for all subjects. The LQMMs showed a significant sub-harmonic amplitude reduction for the mild NPDR subjects compared to the controls; sub-harmonic amplitude for the NDR subjects did not differ significantly from the controls. In contrast, the fundamental response did not differ among the groups for stimulus frequencies between 33 and 38 Hz. Modeling these results indicated that subharmonic amplitude loss in mild NPDR subjects may be attributed to attenuated feedback occurring early in the retina, possibly at the synapse of cone photoreceptors and OFF bipolar cells.

Procedure costs associated with the use of Harmonic devices compared to conventional techniques in various surgeries: a systematic review and meta-analysis

Background

As compared to conventional techniques, recent meta-analyses have reported cost savings with Harmonic devices; however, only in thyroidectomy. Thus, the aim of this study was to evaluate the costs associated with Harmonic devices versus conventional techniques across a range of surgical procedures.

Methods

A systematic search of MEDLINE, EMBASE, and Cochrane Library was conducted from inception to October 01, 2016 without language restrictions to identify randomized controlled trials comparing Harmonic devices to conventional techniques and reporting procedure costs (operating time plus operating equipment/consumables/device costs). Costs were pooled using the ratio of geometric means, and a random effects model was applied. Sensitivity analyses varying statistical methods, number of included studies, and cost outcomes were completed to test the robustness of the results.

Results

Thirteen studies met the inclusion criteria. A total of 561 and 540 participants had procedures performed with Harmonic devices and conventional methods, respectively, with procedures including gastrectomy, thyroidectomy, colectomy, cholecystectomy, Nissen fundoplication, and pancreaticoduodenectomy. As compared to conventional methods, Harmonic devices reduced total procedure costs by 8.7% (p=0.029), resulting in an absolute reduction of US$227.77 from mean conventional technique costs, derived primarily from a reduction in operating time costs. When operating time costs, excluding operating equipment/consumables/device costs, were analyzed, costs were reduced by $544 per procedure with the use of Harmonic devices. The results from all sensitivity analyses demonstrated cost reductions with Harmonic devices.

Conclusion

This systematic review and meta-analysis showed that despite a higher device cost, Harmonic devices provide a statistically significant reduction in procedure costs, derived primarily from a reduction in operating time costs, across surgical procedures. In addition to functionality benefits, Harmonic devices may represent a potentially cost saving method to reduce overall hospital resource use. Future research should focus on potential costs and benefits from use of Harmonic devices in procedures not covered here.

Impact of Ultrasonic Scalpels for Liver Parenchymal Transection on Postoperative Bleeding and Bile Leakage

BACKGROUND/AIM

Novel techniques for liver parenchymal transection have emerged and they are available to the hepatobiliary surgeon. The aim of our study was to compare two types of ultrasonic scalpels (Lotus and Harmonic) and examine how they perform either alone or in combination with the SonaStar ultrasonic surgical aspiration system regarding postoperative bleeding and bile leakage.

PATIENTS AND METHODS

Our prospectively maintained database of patients who underwent liver resections in our Department was reviewed. One hundred and two patients with solid liver lesions underwent liver resection by a senior hepatobiliary surgeon in our department during a period of 51 months. They were divided into four groups according to the devices that were used for liver parenchymal transection.

RESULTS

Patients were divided into the following groups: group 1: Lotus, 32 patients (31.4%); group 2: Lotus+SonaStar, 27 patients (26.5%); group 3: Harmonic, 27 patients (26.5%); group 4: Harmonic+SonaStar, 16 patients (15.7%). There were 5 cases of postoperative bleeding and 9 cases of postoperative bile leakage. No significant difference was found concerning postoperative bleeding (group 1: 2/32; 6.3%, group 2: 2/27; 7.4%, group 3: 0/27; 0%, group 4: 1/16; 6.3%) (p=0.577). Furthermore, no actual difference was detected in terms of postoperative bile leakage (group 1: 2/32; 6.3%, group 2: 3/27; 11.1%, group 3: 3/27; 11.1%, group 4: 1/16; 6.3%) (p=0.866).

CONCLUSION

Both Lotus and Harmonic ultrasonic scalpels provide adequate and similar results concerning postoperative hemorrhage and cholorrhea.

Impact of Ultrasonic Scalpels for Liver Parenchymal Transection on Postoperative Bleeding and Bile Leakage

BACKGROUND/AIM

Novel techniques for liver parenchymal transection have emerged and they are available to the hepatobiliary surgeon. The aim of our study was to compare two types of ultrasonic scalpels (Lotus and Harmonic) and examine how they perform either alone or in combination with the SonaStar ultrasonic surgical aspiration system regarding postoperative bleeding and bile leakage.

PATIENTS AND METHODS

Our prospectively maintained database of patients who underwent liver resections in our Department was reviewed. One hundred and two patients with solid liver lesions underwent liver resection by a senior hepatobiliary surgeon in our department during a period of 51 months. They were divided into four groups according to the devices that were used for liver parenchymal transection.

RESULTS

Patients were divided into the following groups: group 1: Lotus, 32 patients (31.4%); group 2: Lotus+SonaStar, 27 patients (26.5%); group 3: Harmonic, 27 patients (26.5%); group 4: Harmonic+SonaStar, 16 patients (15.7%). There were 5 cases of postoperative bleeding and 9 cases of postoperative bile leakage. No significant difference was found concerning postoperative bleeding (group 1: 2/32; 6.3%, group 2: 2/27; 7.4%, group 3: 0/27; 0%, group 4: 1/16; 6.3%) (p=0.577). Furthermore, no actual difference was detected in terms of postoperative bile leakage (group 1: 2/32; 6.3%, group 2: 3/27; 11.1%, group 3: 3/27; 11.1%, group 4: 1/16; 6.3%) (p=0.866).

CONCLUSION

Both Lotus and Harmonic ultrasonic scalpels provide adequate and similar results concerning postoperative hemorrhage and cholorrhea.

A Fast Recursive Algorithm For Spectrum Tracking in Power Grid Systems

A major challenge for future wide area measurement systems is how to efficiently monitor and control the power system, which requires accurate and real-time tracking of the phase, frequency, and Power Factor (PF) of the system. The presence of inter and sub harmonics, especially in a distribution system caused by widely used non-linear power loads, rectifiers, and inverters, will distort estimation of phase/frequency and make it difficult to track the voltage, current and frequency variations. In this paper we present a new approach to identify and track the harmonics, sub-harmonics and inter-harmonics, as well as observe their impact on the power system. We propose a two-stage processing approach that consists of a subspace-based estimation method to detect and identify all harmonic components, followed by a low-complexity fast tracking algorithm to monitor frequency variations of voltage and current signals in real-time with great accuracy. The simulation results show that the proposed approach can provide highly reliable estimation and fast tracking of the harmonic components, while avoiding the impact of time variance.

Dependence of cavitation, chemical effect, and mechanical effect thresholds on ultrasonic frequency

Cavitation, chemical effect, and mechanical effect thresholds were investigated in wide frequency ranges from 22 to 4880kHz. Each threshold was measured in terms of sound pressure at fundamental frequency. Broadband noise emitted from acoustic cavitation bubbles was detected by a hydrophone to determine the cavitation threshold. Potassium iodide oxidation caused by acoustic cavitation was used to quantify the chemical effect threshold. The ultrasonic erosion of aluminum foil was conducted to estimate the mechanical effect threshold. The cavitation, chemical effect, and mechanical effect thresholds increased with increasing frequency. The chemical effect threshold was close to the cavitation threshold for all frequencies. At low frequency below 98kHz, the mechanical effect threshold was nearly equal to the cavitation threshold. However, the mechanical effect threshold was greatly higher than the cavitation threshold at high frequency. In addition, the thresholds of the second harmonic and the first ultraharmonic signals were measured to detect bubble occurrence. The threshold of the second harmonic approximated to the cavitation threshold below 1000kHz. On the other hand, the threshold of the first ultraharmonic was higher than the cavitation threshold below 98kHz and near to the cavitation threshold at high frequency.

[Use of Harmonic blade in face lifting]

INTRODUCTION

Rapid recovery and return to social activities are what every patient wishes when considering to undergo a face lifting procedure. In our practice, the use of the Harmonic scalpel in order to achieve this goal has greatly improved the postoperative period.

PATIENTS AND METHODS

We have performed 920 face lifting procedures exclusively using the Harmonic scalpel from 2001 to May 2017.

RESULTS

A retrospective chart review was performed. Mean operative time was 110minutes for facelift involving SMAS plication only, and 180minutes for facelift involving SMAS plication with the addition of submental approach for anterior platysma plasty. Return to normal social life was achieved on the 8th postoperative day for the majority of cases.

CONCLUSION

The use of the Harmonic scalpel, once properly integrated in the face lifting procedure, significantly reduces postoperative ecchymosis and oedema and allows a prompt return to normal social life.

Parotidectomy using the Harmonic scalpel: ten years of experience at a rural academic health center

Background

Parotidectomy is one of the most commonly performed procedures by otorhinolaryngologists. Traditionally dissection is performed with a combination of a steel scalpel and bipolar cautery; however, starting in the early 2000s, the Harmonic scalpel has provided an alternative method for dissection and hemostasis. The purpose of this study is to compare operative time, blood loss, complications, and cost between the Harmonic scalpel and steel scalpel plus bipolar cautery for superficial and total parotidectomy.

Methods

Retrospective cohort of patients who underwent superficial or total parotidectomy with the Harmonic or cold steel between 2000 and 2015. Across 255 patients, comparison between operative time, blood loss, complications, and cost was performed.

Results

Superficial parotidectomy was performed on 120 patients with the Harmonic and 54 with steel scalpel. Total parotidectomy was performed on 59 patients using the Harmonic and 22 patients with cold steel. For superficial parotidectomy, the Harmonic reduced operative time (216 ± 42 vs. 234 ± 54 min, p = 0.03) and decreased blood loss (28 ± 19 vs. 76 ± 52 mls, p < 0.05). With total parotidectomy the Harmonic decreased operative time (240 ± 42 vs. 288 ± 78 min, p = 0.01) and reduced blood loss (38 ± 21 mls vs. 85 ± 55 mls, p < 0.05). There were no differences in complication rates between groups. Harmonic use was associated with surgical cost reduction secondary to reduced operative times.

Conclusions

The Harmonic scalpel decreases blood loss and operating time for superficial and total parotidectomy. Shorter operative times may decrease the overall cost of parotidectomy.

Effect of energy-based devices on voice quality after total thyroidectomy

Voice alteration is an important complication of thyroid surgery and is closely related to patients' quality of life. There are no studies analyzing effect of energy-based devices (EBD) on voice quality (VQ). Aim of this prospective study is to evaluate impact of sutureless total thyroidectomy performed with EBDs on objective voice parameters of patients without recurrent laryngeal nerve (RLN) and/or external branch of superior laryngeal nerve (EBSLN) injury. Sixty patients underwent total thyroidectomy with meticulous dissection of EBSLN. Patients were assigned to Group L (Ligasure™), Group H (Harmonic), or Group C (Conventional) through random ballot. For analysis of alteration in VQ, digital videolaryngostroboscopy (VLS), voice handicap index (VHI), multidimensional voice program (MDVP), and electroglottography (EGG) were used. VLS was performed by 70°-angled indirect laryngoscopy and evaluation was standardized by VLS scale and laryngeal function scoring. This study is registered on clinicaltrials.gov with number NCT01865006. Forty eight patients were female. There was no difference on demographic data. On post-operative laryngoscopic examination, none of the patients had vocal fold palsy. When mean VHI scores at post-operative 1st week and 2nd month were compared to pre-operative values for each groups, groups L and H demonstrated a significant increase in VHI in the early post-operative evaluation, while there was no significant increase for group C. No significant increase was seen in late post-operative period compared to pre-operative period for any groups. In the early post-operative period, VQ is better with the conventional technique than EBDs; however, in late post-operative period, VQ is detected better in EBDs (especially in Group L) than the conventional technique, but no statistical difference was observed.

Ultrasonic, bipolar, and integrated energy devices: comparing heat spread in collateral tissues

BACKGROUND

Integrated devices incorporating ultrasonic and bipolar technology have been used in laparoscopic surgery, however, are not yet incorporated into open operations. Here, we compare thermal spread and recurrent laryngeal nerve (RLN) functional data of the integrated THUNDERBEAT Open Fine Jaw device, the bipolar Ligasure Small Jaw, and the ultrasonic Harmonic Focus for open thyroidectomy.

MATERIALS AND METHODS

The three energy devices were compared in a live porcine model using three tissue types including liver, muscle, and thyroid. The devices were fired three times on each energy setting, and the thermal spread was measured by thermocouples that were inserted in surrounding tissues at 1-mm intervals. To determine RLN injury, devices were fired at successive 1-mm increments from the RLN until the monitor signal was lost.

RESULTS

When comparing heat generated across these devices at 1 mm, the peak temperature (Celsius) reached in liver tissue was observed with the ultrasonic device (115.4 ± 86.7), in muscle tissue with the integrated device (104.2 ± 82.1), and in thyroid with the bipolar device (81.4 ± 41.3). Temperatures generated at individual settings on each device were similar (P = 0.11-0.81). RLN injury occurred after firing on manually approximated tissue 1-mm away from the RLN for all devices; however, there was no signal loss at ≥2 mm.

CONCLUSIONS

Heat transfer was similar among all devices with the exception of the ultrasonic device when used in the liver, which showed higher temperatures. Liver tissue showed the most consistent results. RLN injury did not occur if the devices were fired on manually approximated tissue ≥2 mm from the nerve.

Clinical utility of a novel ultrasonic vessel sealing device in transecting and sealing large vessels during laparoscopic hysterectomy using advanced hemostasis mode

OBJECTIVE(S)

The ultrasonic advanced energy study device (AH device) is the first surgical device indicated to seal vessels up to and including 7mm using ultrasonic technology alone. This study assesses clinical experience during total laparoscopic hysterectomy (TLH) using advanced hemostasis mode (AHM).

STUDY DESIGN

This was a prospective, non-randomized, single arm, multicenter, observational study which did not modify or influence current surgeon technique for elective TLH for benign disease. Each surgeon assessed hemostasis, defined as the hemostatic transection of the uterine vasculature (left/right) with at least one use of the AH device in AHM without the use of additional hemostatic measures other than the AH device. Patients were followed for 4-6 weeks after surgery. Vessel sealing performance was quantitatively assessed for transection and sealing of the uterine artery (UA), the uterine pedicle (UP; defined as cases where the UA could not be 'isolated') and the ovarian pedicle (OP) (when indicated). Adverse events (AEs) related to the AH device or procedures were collected.

RESULTS

Forty patients underwent the procedure. Mean age was 49 years and mean body mass index was 28kg/m(2). Mean surgical duration was 88min. None required conversion to open procedure. Using only the AH device, hemostasis was achieved and maintained in 119 (94.4%) transections (both left and right sides of the UA/UP and OP). Additional hemostasis was achieved in 5 patients using conventional bipolar (4) or monopolar (1) energy. No patient required a blood transfusion postoperatively. Only one adverse event of pain was considered to be related to the use of the ultrasonic AH device during this study.

CONCLUSION

These results support that the AH device with its AHM has clinical utility in sealing named vessels in TLH. The new algorithm to deliver energy in the AHM has the potential to reduce the need for additional hemostatic devices or products as well as the potential to reduce the need for multiple instrument changes during surgery.

Optimization of Contrast-to-Tissue Ratio Through Pulse Windowing in Dual-Frequency "Acoustic Angiography" Imaging

Early-stage tumors in many cancers are characterized by vascular remodeling, indicative of transformations in cell function. We have previously presented a high-resolution ultrasound imaging approach to detecting these changes that is based on microbubble contrast agents. In this technique, images are formed from only the higher harmonics of microbubble contrast agents, producing images of vasculature alone with 100- to 200-μm resolution. In this study, shaped transmit pulses were used to image the higher broadband harmonic echoes of microbubble contrast agents, and the effects of varying pulse window and phasing on microbubble and tissue harmonic echoes were evaluated using a dual-frequency transducer in vitro and in vivo. An increase in the contrast-to-tissue ratio of 6.8 ± 2.3 dB was observed in vitro using an inverted pulse with a cosine window relative to a non-inverted pulse with a rectangular window. The increase in mean image intensity resulting from contrast enhancement in vivo in five rodents was 13.9 ± 3.0 dB greater for an inverted cosine-windowed pulse and 17.8 ± 3.6 dB greater for a non-inverted Gaussian-windowed pulse relative to a non-inverted pulse with a rectangular window. Implications for pre-clinical and diagnostic imaging are discussed.

On the relationship between microbubble fragmentation, deflation and broadband superharmonic signal production

Acoustic angiography imaging of microbubble contrast agents uses the superharmonic energy produced from excited microbubbles and enables high-contrast, high-resolution imaging. However, the exact mechanism by which broadband harmonic energy is produced is not fully understood. To elucidate the role of microbubble shell fragmentation in superharmonic signal production, simultaneous optical and acoustic measurements were performed on individual microbubbles at transmit frequencies from 1.75 to 3.75 MHz and pressures near the shell fragmentation threshold for microbubbles of varying diameter. High-amplitude, broadband superharmonic signals were produced with shell fragmentation, whereas weaker signals (approximately 25% of peak amplitude) were observed in the presence of shrinking bubbles. Furthermore, when populations of stationary microbubbles were imaged with a dual-frequency ultrasound imaging system, a sharper decline in image intensity with respect to frame number was observed for 1-μm bubbles than for 4-μm bubbles. Finally, in a study of two rodents, increasing frame rate from 4 to 7 Hz resulted in decreases in mean steady-state image intensity of 27% at 1000 kPa and 29% at 1300 kPa. Although the existence of superharmonic signals when bubbles shrink has the potential to prolong the imaging efficacy of microbubbles, parameters such as frame rate and peak pressure must be balanced with expected re-perfusion rate to maintain adequate contrast during in vivo imaging.

Studies on thermo-elastic heating of horns used in ultrasonic plastic welding

Ultrasonic welding horn is half wavelength section or tool used to focus the ultrasonic vibrations to the components being welded. The horn is designed in such a way that it maximizes the amplitude of the sound wave passing through it. The ends of the horn represent the displacement anti-nodes and the center the 'node' of the wave. As the horns perform 20,000 cycles of expansion and contraction per second, they are highly stressed at the nodes and are heated owing to thermo-elastic effects. Considerable temperature rise may be observed in the horn, at the nodal region when working at high amplitudes indicating high stress levels leading to failure of horns due to cyclic loading. The limits for amplitude must therefore be evaluated for the safe working of the horn. Horns made of different materials have different thermo-elastic behaviors and hence different temperatures at the nodes and antinodes. This temperature field can be used as a control mechanism for setting the amplitude/weld parameters. Safe stress levels can be predicted using modal and harmonic analyses followed by a stress analysis to study the effect of cyclic loads. These are achieved using 'Ansys'. The maximum amplitude level obtained from the stress analysis is used as input for 'Comsol' to predict the temperature field. The actual temperature developed in the horn during operation is measured using infrared camera and compared with the simulated temperature. From experiments, it is observed that horn made of titanium had the lowest temperature rise at the critical region and can be expected to operate at amplitudes up to 77 μm without suffering failure due to cyclic loading. The method of predicting thermo-elastic stresses and temperature may be adopted by the industry for operating the horn within the safe stress limits thereby extending the life of the horn.

Recent advances in the management of hemorrhoids

Hemorrhoids are considered one of the most common anorectal diseases with a prevalence of 4.4% up to 36.4% of the general population, and a peak incidence between 45 and 65 years. Hemorrhoidal disease presents with a prolapsed lump, painless bleeding, discomfort, discharge, hygiene problems, soiling, and pruritus. Sliding anal canal lining theory is the most accepted theory as a cause of hemorrhoidal disease; however, it is also associated with hyper-vascularity, and, recently, with several enzymes or mediators involved in the disintegration of the tissues supporting the anal cushions, such as matrix metalloproteinase. A comprehensive search in published English-language literature till 2013 involving hemorrhoids was performed to construct this review article, which discusses advances in the management of hemorrhoids. This includes conservative treatment (life style modification, oral medications, and topical treatment), office procedures (rubber band ligation, injection sclerotherapy, infrared and radiofrequency coagulation, bipolar diathermy and direct-current electrotherapy, cryosurgery, and laser therapy), as well as surgical procedures including diathermy hemorrhoidectomy, LigaSure hemorrhoidectomy, Harmonic scalpel hemorrhoidectomy, hemorrhoidal artery ligation, stapled hemorrhoidopexy (SH), and double SH. Results, merits and demerits of the different modalities of treatment of hemorrhoids are presented, in addition to the cost of the recent innovations.

The use of FOCUS Harmonic scalpel compared to conventional haemostasis (knot and tie ligation) for thyroid surgery: a prospective randomized study

Haemostasis is crucial in thyroid surgery to avoid intraoperative and postoperative complications. In the present study, we evaluated the efficiency and the safety of Harmonic scalpel when compared to conventional suture ligation in open total thyroidectomy. We enrolled 265 patients who underwent total thyroidectomy for multinodular disease since October 2011 up to October 2013. They were randomized into two groups: 141 in group HS (Harmonic Scalpel), 124 in group CT (Conventional tecnique). We recorded the following data: operative time, post-operative blood loss, length of hospital stay and complications. The patients were monitored for 48 hours after surgery. Several differences were observed between the two groups (HS vs CT): the use of Harmonic scalpel was associated to a significant reduction of surgical operative time (110 min in CT vs 79.36 min in HS, p = 0.00001) and also associated to a lower blood loss (97.38 ml in CT vs 68.72 ml in HS, p = 0.00001). The length of stay was significantly shorter in the HS group (2.75 days in CT vs 1.93 days in HS) Complication rate was similar in the two groups. According to our experience, the Harmonic scalpel represents a safe alternative to conventional haemostasis in thyroid surgery, allowing for a significant reduction of operative time, blood loss and hospitalization. The rate of complication demonstrated no significant difference among the two groups.

Harmonic imaging with fresnel beamforming in the presence of phase aberration

Fresnel beamforming is a beamforming method with a delay profile similar in shape to a physical Fresnel lens. The advantage of Fresnel beamforming is the reduced channel count, which consists of four to eight transmit and two analog-to-digital receive channels. Fresnel beamforming was found to perform comparably to conventional delay-and-sum beamforming. However, the performance of Fresnel beamforming is highly dependent on focal errors. These focal errors result in high side-lobe levels and further reduce the performance of Fresnel beamforming in the presence of phase aberration. With the advantages of lower side-lobe levels and suppression of aberration effects, harmonic imaging offers an effective solution to the limitations of Fresnel beamforming. We describe the implementation of tissue harmonic imaging and pulse inversion harmonic imaging in Fresnel beamforming, followed by dual apodization with cross-correlation, to improve image quality. Compared with conventional delay-and-sum beamforming, experimental results indicated contrast-to-noise ratio improvements of 10%, 49% and 264% for Fresnel beamforming using tissue harmonic imaging in the cases of no aberrator, 5-mm pork aberrator and 12-mm pork aberrator, respectively. These improvements were 22%, 57% and 352% for Fresnel beamforming using pulse inversion harmonic imaging. Moreover, dual apodization with cross-correlation was found to further improve the contrast-to-noise ratios in all cases. Harmonic imaging was also found to narrow the lateral beamwidth and shorten the axial pulse length by at least 25% and 21%, respectively, for Fresnel beamforming at different aberration levels. These results suggest the effectiveness of harmonic imaging in improving image quality for Fresnel beamforming, especially in the presence of phase aberration. Even though this combination of Fresnel beamforming and harmonic imaging does not outperform delay-and-sum beamforming combined with harmonic imaging, it provides the benefits of reduced channel count and potentially reduced cost and size of ultrasound systems.

Sealing vessels up to 7 mm in diameter solely with ultrasonic technology

Introduction

Ultrasonic energy is a mainstay in the armamentarium of surgeons, providing multifunctionality, precision, and control when dissecting and sealing vessels up to 5 mm in diameter. Historically, the inability to seal vessels in the 5–7 mm range has been perceived as an inherent limitation of ultrasonic technology. The purpose of this study was to evaluate sealing of vessels up to 7 mm in diameter with an ultrasonic device that modulates energy delivery during the sealing period.

Methods

In ex vivo benchtop and in vivo acute and survival preclinical models, a new ultrasonic device, Harmonic ACE^®+7 Shears (Harmonic 7), was compared with advanced bipolar devices in sealing vessels 1–7 mm in diameter with respect of burst pressure, seal reliability, and seal durability. Lateral thermal damage and transection time were also evaluated.

Results

Ex vivo tests of Harmonic 7 demonstrated significantly greater median burst pressures than an advanced bipolar device both for vessels <5 mm in diameter (1,078 mmHg and 836 mmHg, respectively, P=0.046) and for those in the range of 5–7 mm (1,419 mmHg and 591 mmHg, P<0.001). In vivo tests in porcine and caprine models demonstrated similar rates of hemostasis between Harmonic 7 and advanced bipolar devices, with high success rates at initial transection and seal durability of 100% after a 30-day survival period.

Conclusion

Sealing 5–7 mm vessels is not a limitation of the type of energy used but of how energy is delivered to tissue. These studies document the ability of ultrasonic energy alone to reliably seal large vessels 5–7 mm in diameter, with significantly greater burst pressure observed in in vitro studies than those observed with an advanced bipolar technology when energy delivery is modulated during the sealing cycle. Furthermore, the seals created in 5–7 mm vessels are shown to be reliable and durable in in vivo preclinical studies.

Past, Present, and Future of the Pulse Examination ( mài zhěn)

The pulse examination (脈診 mài zhěn) is a unique diagnostic approach of Traditional Chinese Medicine. The description of pulse examination in the history of Traditional Chinese Medicine is full of amazement and mythology. After researching in hemodynamics and investigating in clinical application for three decades, this article describes the development and the merits and demerits of pulse examination. The experiences of the ancients are tried to be illustrated with modern knowledge and language. As the theory of resonant blood circulation is discovered, Traditional Chinese Medicine could be on the shoulder of Newton and then lead the development of modern medicine. Hope the tool of pulse examination constructed according to eigen-vector with specific time domain and position can bring the running water for Traditional Chinese Medicine. Quantitative research could overcome the plight of analog logic qualitative research, and therefore bring new health revolution.

The safety of the Harmonic® FOCUS in open thyroidectomy: a prospective, randomized study comparing the Harmonic® FOCUS and traditional suture ligation (knot and tie) technique

Since Kocher and Billroth refined an acceptable technique, the thyroidectomy has become one of the most frequent procedures in endocrine surgery and bilateral total thyroidectomy is performed in the majority of thyroid diseases. This work evaluated the use of the Harmonic(®) FOCUS and traditional suture ligation (knot and tie) technique in a prospective, randomized study of open thyroidectomy. Eighty two patients were randomized and divided into two similarly sized groups: the Harmonic(®) FOCUS group (F group) and traditional group (T group). The use of the harmonic FOCUS shows some statistically significant advantages limited to a few intraoperative parameters: surgical time and volume of blood loss. The surgical time was significantly shorter in F group than in the T group (105 ± 27 min vs 143 ± 32 respectively; p < 0.05). Intraoperative volume blood loss was significantly more in the T group than in the F group (36 ± 23 ml vs. 24 ± 18; p < 0.05). The postoperative parameters (volume of drainage fluid, serum calcium at 12 and 48 h, hypocalcemia, wound complication, RLN palsy, postoperative pain and length of hospital stay) showed no statistical difference. The Harmonic Focus may provide a cost-effective option only in high volume centers where reducing operative time may balance the number of daily procedures.

Resection of giant gastric GIST with a new generation ultrasonic scalpel device

Gastrointestinal stroma tumours (GIST) are the most common mesenchymal tumour in the digestive tract and commonly found in the stomach. The patient described in this report presented with collapse and a palpable abdominal mass. He was found to have a large gastric GIST that penetrated through the mesocolon. Resection of the GIST was technically challenging but facilitated by a new generation ultrasonic scalpel device. In resection of gastric cancer the use of ultrasonic scalpels has been shown to reduce operating time, blood loss and length of stay. We feel that in technically challenging cases of gastric GIST the use of an ultrasonic scalpel device may be justified as well.

Tissue effects in vessel sealing and transection from an ultrasonic device with more intelligent control of energy delivery

BACKGROUND

Ultrasonic surgical devices have been demonstrated to provide excellent hemostasis, efficient transection, minimal lateral thermal damage, low smoke generation, and no risk of electrical current passage to the patient. These benefits originate from the inherent characteristics of the ultrasonic mechanism, but further improvements were thought possible through optimization of the energy delivery during application. The study reported here compared a new ultrasonic device, Harmonic ACE®+ Shears with Adaptive Tissue Technology, with a commercial predicate device, Harmonic ACE® Shears (both Ethicon Endo-Surgery, Inc., Cincinnati, OH, USA).

METHODS

Devices were evaluated in an in vivo porcine model intraoperatively and after a 30-day survival period. Both devices were used to seal a variety of vessels 1-5 mm in diameter, and compared for hemostasis, histological thermal damage, and adhesion formation. Sealed vessels were evaluated ex vivo for burst pressure, and visual obstruction caused by plumage from device application was assessed quantitatively.

RESULTS

ACE+ produced significantly less thermal damage, had fewer adhesions, offered faster transection, involved less visual obstruction, and had higher burst pressures than the predicate device. All vessel seals, evaluated over the course of a 30-day survival period in pigs, remained intact.

CONCLUSION

The new Adaptive Tissue Technology algorithm assists the surgeon in achieving better control of energy delivery to the tissue, sealing vessels with supra-physiological burst pressures, and low thermal damage. These preclinical results with Harmonic ACE+ may translate into meaningful clinical benefits, providing greater precision along with more efficient and effective cutting and coagulation in open or laparoscopic procedures.

Second harmonic and subharmonic for non-linear wideband contrast imaging using a capacitive micromachined ultrasonic transducer array

When insonified with suitable ultrasound excitation, contrast microbubbles generate various non-linear scattered components, such as the second harmonic (2H) and the subharmonic (SH). In this study, we exploit the wide frequency bandwidth of capacitive micromachined ultrasonic transducers (CMUTs) to enhance the response from ultrasound contrast agents by selective imaging of both the 2H and SH components simultaneously. To this end, contrast images using the pulse inversion method were recorded with a 64-element CMUT linear array connected to an open scanner. In comparison to imaging at 2H alone, the wideband imaging including both the 2H and SH contributions provided up to 130% and 180% increases in the signal-to-noise and contrast-to-tissue ratios, respectively. The wide-frequency band of CMUTs offers new opportunities for improved ultrasound contrast agent imaging.