Endoscopic suturing and knot tying: theory into practice

Beyond the Square knot: A validation study for a novel knot-tying method named "inverse 9"

Purpose

We compared the "inverse 9" laparoscopic suturing and knot-tying (LSKT) method to the traditional LSKT method in a validation study to demonstrate the "inverse 9" method's superiority and effectiveness in laparoscopy.

Methods

On the basis of their experience in laparoscopic surgery, 78 trainees were divided into two groups, with 52 inexperienced trainees in group A and 26 experienced trainees in group B. In group A, 52 trainees were randomly allocated to either group A1 ("inverse 9" LSKT training) or group A2 (traditional LSKT training). In group B, experienced trainees were randomly assigned to receive "inverse 9" LSKT training (group B1) or continuing training in the traditional LSKT method (group B2). All trainees received the same instruction and assessment and were asked to provide a subjective assessment of the two training methods at the end of the training.

Results

The trainees in groups A1, A2, and B had similar average ages and were mostly male. After training, all showed preliminary mastery of LSKT (P < 0.05). The trainees in groups A1 and B1 achieved learning proficiency in the fifth assessment, while those in group A2 achieved it in the sixth assessment. The trainees in groups A1 and B1 showed lower difficulty in achieving mastery and lower operation fatigue scores (P < 0.05), and 61.50 % of the trainees in group B preferred the "inverse 9" method in subjective evaluation.

Conclusion

As a novel LSKT technique, "inverse 9" offers a multitude of benefits. In addition to ensuring a simpler operation and effectively reducing the knot-tying time, it also involves a shorter learning curve than traditional LSKT methods. As such, it can be easily mastered and widely adopted as a standard LSKT technique.

The effect of inherent and incidental constraints on bimanual and social coordination

The current investigation was designed to examine the influence of inherent and incidental constraints on the stability characteristics associated with bimanual and social coordination. Individual participants (N = 9) and pairs of participants (N = 18, 9 pairs) were required to rhythmically coordinate patterns of isometric forces in 1:1 in-phase and 1:2 multi-frequency patterns by exerting force with their right and left limbs. Lissajous information was provided to guide performance. Participants performed 13 practice trials and 1 test trial per pattern. On the test trial, muscle activity from the triceps brachii muscles of each arm was recorded. EMG-EMG coherence between the two EMG signals was calculated using wavelet coherence. The behavioral data indicated that individual participants performed the 1:1 in-phase pattern more accurately and with less variability than paired participants. The EMG coherence analysis indicated significantly higher coherence for individual participants than for the paired participants during the 1:1 in-phase pattern, whereas no differences were observed between groups for the 1:2 coordination pattern. The results of the current investigation support the notion that neural crosstalk can stabilize 1:1 in-phase coordination when contralateral and ipsilateral signals are integrated via the neuromuscular linkage between two effectors.

Accessing interpersonal and intrapersonal coordination dynamics

Both intrapersonal and interpersonal coordination dynamics have traditionally been investigated using relative phase patterns of in-phase (ϕ = 0°) and/or anti-phase (ϕ = 180°). Numerous investigations have demonstrated that coordination tasks that require other relative phase patterns (e.g., 90°) are difficult or near impossible to perform without extended practice. Recent findings, however, have demonstrated that an individual can produce a wide range of intrapersonal bimanual patterns within a few minutes of practice when provided integrated feedback. The present experiment was designed to directly compare intra- and interpersonal coordination performance and variability when provided Lissajous feedback or pacing metronome. Single participants (N = 12) and pairs of participants (N = 24, 12 pairs) were required to produce relative phase patterns between 0° and 180° in 30° increments using either pacing metronomes or Lissajous displays. The Lissajous displays involved a goal template and a cursor providing integrated feedback regarding the position of the two effectors. The results indicated both single and pairs of participants could effectively produce a large range of coordination patterns that typically act as repellers after only 6 min of practice when provided integrated feedback. However, single participants performed the in-phase coordination pattern more accurately and with less variability than paired participants, regardless of the feedback condition. These results suggest an advantage for intrapersonal coordination when performing in-phase coordination, possibly due to the stabilizing effect occurring via the neuro-muscular linkage between effectors.

Learning to tie well with others: bimanual versus intermanual performance of a highly practised skill

Studies indicate that novices are faster in manual tasks when performing with a partner ('intermanual') than with their own two hands ('bimanual'). The generality of this 'mode effect' was examined using a highly practised bimanual task, shoe tying, at which participants were experts. Speed-variability correlations confirmed participants were bimanually skilled but not intermanually skilled. Contrary to results using novices, intermanual was slower, such that prior skill reverses the effect. Analyses incorporating the similarity of shoe-tying strategies across dyads implicated a perceptual rather than shared knowledge/representation basis for intermanual performance. Practice effects indicated that intermanual performance built upon prior bimanual skill, such that novel relative timings between dyads' hands must be acquired. Motor transfer effects provided support for this conclusion. During shoe tying, hands were tightly coupled in the intermanual mode due to the perceptual coupling constraints of intermanual performance. Increased coupling was correlated with slower performance. Implications for real-world tasks (e.g. surgical knot tying) are described.

Are two hands (from different people) better than one? Mode effects and differential transfer between manual coordination modes

OBJECTIVE

We report an experiment in which we investigated differential transfer between unimanual (one-handed), bimanual (two-handed), and intermanual (different peoples' hands) coordination modes.

BACKGROUND

People perform some manual tasks faster than others ("mode effects"). However, little is known about transfer between coordination modes. To investigate differential transfer, we draw hypotheses from two perspectives--information based and constraint based--of bimanual and interpersonal coordination and skill acquisition.

METHOD

Participants drove a teleoperated rover around a circular path in sets of two 2-min trials using two of the different coordination modes. Speed and variability of the rover's path were measured. Order of coordination modes was manipulated to examine differential transfer and mode effects.

RESULTS

Differential transfer analyses revealed patterns of positive transfer from simpler (localized spatiotemporal constraints) to more complex (distributed spatiotemporal constraints) coordination modes paired with negative transfer in the opposite direction. Mode effects indicated that intermanual performance was significantly faster than unimanual performance, and bimanual performance was intermediate. Importantly, all of these effects disappeared with practice.

CONCLUSION

The observed patterns of differential transfer between coordination modes may be better accounted for by a constraint-based explanation of differential transfer than by an information-based one. Mode effects may be attributable to anticipatory movements based on dyads' access to mutual visual information.

APPLICATION

Although people may be faster using more-complex coordination modes, when operators transition between modes, they may be more effective transitioning from simpler (e.g., bimanual) to more complex (e.g., intermanual) modes than vice versa. However, this difference may be critical only for novel or rarely practiced tasks.

The Minailo knot: a time-saving and cost-saving technique

Endoscopic knot tying during minimally invasive surgery can be complicated, time consuming, and associated with a protracted learning curve. The Minailo knot seems to be a reasonable option because the technique does not require any specialized instrumentation or skill to perform. In particular, vaginal closure is obtained with the placement of a single intra-corporeal knot. Our initial and successful experience with this knot-tying technique during robotic hysterectomy for treatment of gynecologic disease suggests that the method is safe and feasible.

Suturing and tying knots assisted by a surgical robot system in laryngeal MIS

Suturing and tying knots assisted by surgical robot systems are complicated and time-consuming tasks in minimally invasive surgery (MIS). It is almost impossible to perform these operations in laryngeal MIS because motions of the end-effectors are greatly confined by a narrow and long laryngoscope tube. This paper presents the robot-assisted operations of suturing and knot-tying in a laryngeal surgery under a self-retaining laryngoscope, which has a greatly confined workspace. In order to use robot assistance to perform the suturing and knot-tying tasks in such a workspace, an appropriate suturing path is planned. The suturing path planning is completed based on a knot-tying algorithm called the bending-twisting knot-tying (BTKT). A robot system for laryngeal MIS called MicroHand III is designed. The kinematical model of the system is developed in the paper. The simulation and experimental results have shown that suturing and knot-tying assisted by MicroHand III system are successful.

Axial-spin technique of endoscopic intracorporeal knot tying: comparison with the conventional technique and objective assessment of knot security, learning curves, and performance efficiency across training levels

INTRODUCTION

A major limitation of conventional laparoscopic surgery is the placement of an intracorporeal (IC) knot, which requires a significant amount of training and practice. An easier technique of IC knot tying using 90-degree grasper is compared with the conventional technique (CLT). The new axial-spin technique (AST) uses the spin of the instrument shaft to tie IC knots.

METHODS

Fourteen participants stratified into 3 training levels were instructed to tie 50 reef IC knots using each technique on trainers in 3 sessions. The final 5 knots tied using each technique were deemed to be representative of maximal performance efficiency (PE) and randomly subject to tensile strength measurements using a tensiometer at 50 mm/s distraction. Mean knot execution time (mKET) measured in seconds (s), normalized KE time (nET=group mean/mKET), knot holding capacity, relative knot security (RKS), and PE (PE=RKS/nET) of the knots tied were computed and analyzed using paired t and analysis of variance.

RESULTS

Variables included knot-tying session, technique and the training level. On completion of the study, junior residents (JR) averaged 51.72 seconds more, senior residents (SR) averaged 26.22 seconds more and attendings (ATT) averaged 19.17 seconds less to tie using CLT compared with the AST (F=40.52, P=0.0001). Across all levels, the CLT technique was taking 83.26 seconds on average to execute an IC knot compared with 59.08 seconds with AST method (t=2.784, P=0.015). Learning curves revealed that JR significantly improved mean KE times with the AST technique (first session vs. final session: 473.8 s vs. 55.9 s) compared with CLT (672.5 s vs. 107.6 s) across the sessions as compared with those in advanced levels of training. The RKS of knots executed by AST was significantly stronger (AST: 13.1 vs. 5.44 N, t=4.9, P=0.0001). The PE of knots executed using the CLT increased geometrically across training levels (JR: 1.35% SR: 5.58% ATT: 11.22%) whereas those of AST showed a linear trend (17.09%; 17.11%, and 13.95%).

CONCLUSION

The AST follows a linear pattern of learning across training levels compared with the steep exponential learning of the CLT. Inexperienced JRs were surprisingly 1.5 times more efficient with AST and 8 times less efficient with CLT compared with ATT using the CLT to execute the same knot. The AST is significantly easier to learn for JRs and could serve as a platform before acquiring more advanced knot-tying skills. Overall, with the AST, execution times are significantly shorter whereas the RKS and PE are significantly higher. JRs achieve a level of proficiency comparable with the senior level residents and ATT after participating in a reasonable training session consisting of at least 25 knots.

A novel knot-tying approach for minimally invasive surgical robot systems

BACKGROUND

In robot-assisted minimally invasive surgery (MIS), knot-tying is an important but challenging task for surgeons when performing surgery by manipulating a master-slave robot system. Knot-tying in the conventional way is restricted by a confined workspace, which may cause the suture loop to be unstable and make knot-tying difficult and time-consuming in robot-assisted MIS.

METHODS

A knot-tying approach named 'bending-twisting knot-tying' (BTKT) has been developed for robot-assisted surgery systems operating in a confined workspace. The non-linear deformation of sutures during knot-tying is qualitatively described using knot theory. The length ratio of a knot (LoK) and the feasible coefficient (Fc) are introduced to evaluate the quality of BTKT knots. Simulations and experiments are performed based on finite segment dynamic models and the MicroHand surgical system, respectively, to describe the dynamic behaviours of the knots. Sensitive parameters, including the length of a suture (L), the distance between two ends (d) and the angle between tangents of the two ends (alpha) are analysed based on the model.

RESULTS

For a terylene suture, the length of the suture L and the distance between the two ends d should satisfy 1.12d< or =L< or =14.4d. When L and alpha are constant, the smaller d is, the larger are LoK and Fc relative to different sutures. A knot of high quality can be tied with a small alpha.

CONCLUSIONS

Simulation and experimental results show that BTKT requires a smaller workspace and can form more stable loops compared to conventional methods.

Automated knot tying for fixation in minimally invasive, robot-assisted cardiac surgery

Cardiovascular disease (CVD) is perhaps the most significant worldwide health issue. While open-heart surgery remains the predominant treatment, significant advancements have been made in minimally invasive surgery (MIS) and minimally invasive robot-assisted (MIRA) surgery. MIRA techniques offer many advantages over open-heart procedures and have extended the capabilities of MIS. However, these benefits come at the cost of increased operating times due to time spent tying knots. The additional bypass time limits patient access and is the most significant barrier to the adoption of MIRA techniques. This research seeks to overcome this barrier by designing a device for MIRA cardiac procedures that automates the knotting of sutures. If this task can be automated while ensuring the delivery of high-quality knots, great progress can be made in transforming the field. MIRA cardiac procedures can move from novel procedures performed by a select group of surgeons on a limited pool of patients to a viable alternative available to the majority of patients with CVD. In this research we propose a design for a self-contained device that delivers a locking knot. Results suggest that consistent knots can be delivered at a time savings of 12.5% and 26.4% over manual knots for trained and untrained users of a surgical robot, respectively.

Analysis and physics of laparoscopic intracorporeal square-knot tying

Square knots are often used in open surgery to approximate tissue borders or tie off tubular structures like vessels or ducts. Three common methods are used for surgical square-knot tying: one-hand tying, two-hand tying, and the instrument-tying technique. Two types of suture placements are studied in both the open and laparoscopic surgical fields. The first called equal length has suture segment ends placed at equal distances from the tying site. The second called unequal length has one suture end further away from the tying site than the other. Laparoscopic intracorporeal square-knot tying maneuvers are analyzed herein. Mechanical analysis of square-knot tying movements reveals that regardless of location or method used in construction, all square knots consist of 2 half-knots. For study purposes, these sets of movements are identified in laparoscopy as maneuver A and maneuver B. Further breakout of these maneuvers reveals that they consist of 5 motions. This study reveals that 16 different ways exist to place a square knot by means of the laparoscopic intracorporeal technique. It is likely that difficulty mastering this essential skill is not just the result of poor instrumentation, improper port placement, or the limitations of a 2-dimensional video image. It may also be attributed to mixing up the different square-knot tying techniques during random practice exercises. This is possible if the surgeon is ignorant of the technical variations present in what most people consider a simple task.

A New Technique for Tying the Gea Extracorporeal Knot for Endoscopic Surgery

The development of minimally invasive surgery has promoted new knot elaboration techniques. The Gea extracorporeal knot was described in our institution for use in laparoscopic surgery and has demonstrated to be excellent for endoscopic surgical procedures. Our experience has provided some changes in the technique to facilitate the elaboration of the Gea knot. Here we present an alternative tying technique for the Gea knot and slip loop.