The value of force and torque measurements in transanal total mesorectal excision (TaTME)

Abstract

Background Transanal total mesorectal excision (TaTME) is associated with a relatively long learning curve. Force, motion, and time parameters are increasingly used for objective assessment of skills to enhance laparoscopic training efficacy. The aim of this study was to identify relevant metrics for accurate skill assessment in more complex transanal purse-string suturing. Methods A box trainer was designed for TaTME and equipped with two custom made multi-DOF force/torque sensors. These sensors measured the applied forces in the axial direction of the instruments (Fz), instrument load orientation expressed in torque (Mx and My) on the entrance port, and the full tissue interaction force (Fft) at the intestine fixation point. In a construct validity study, novices for TaTME performed a purse-string suture to investigate which parameters can be used best to identify meaningful events during tissue manipulation and instrument handling. Results Significant differences exist between pre-and post-training assessment for the mean axial force at the entrance port Fz (p = 0.01), mean torque in the entrance port Mx (p = 0.03) and mean force on the intestine during suturing Fft (p = 0.05). Furthermore, force levels during suturing exceed safety threshold values, potentially leading to dangerous complications such as rupture of the rectum. Conclusions Forces and torque measured at the entrance port, and the tissue interaction force signatures provide detailed insight into instrument handling, instrument loading, and tissue handling during purse-string suturing in a TaTME training setup. This newly developed training setup for single-port laparoscopy that enables objective feedback has the potential to enhance surgical training in TaTME.

Tool-tissue forces in surgery: A systematic review

“…In regard to study demographics, all studies were primarily conducted at North American (n = 19) [ 2 , 4 , 14 , [17] , [18] , [19] , [20] , [21] , [22] , [23] , [24] , [25] , [26] , [27] , [28] , [29] , [30] , [31] , [32] , [33] ] or European (n = 26) [ 1 , 3 , 5 , [34] , [35] , [36] , [37] , [38] , [39] , [40] , [41] , [42] , [43] , [44] , [45] , [46] , [47] , [48] , [49] , [50] , [51] , [52] , [53] , [54] , [55] ] institutions ( Supplementary Information 2 ). Articles were published in medical (n = 26) [ [2] , [3] , [4] , 14 , [21] , [22] , [23] , 25 , 27 , 29 , 35 , 36 , 43 , [46] , [47] , [48] , [49] , 51 , 53 ] or engineering (n = 19) [ <...>…”

“…Articles were published in medical (n = 26) [ [2] , [3] , [4] , 14 , [21] , [22] , [23] , 25 , 27 , 29 , 35 , 36 , 43 , [46] , [47] , [48] , [49] , 51 , 53 ] or engineering (n = 19) [ 1 , 5 , [17] , [18] , [19] , [20] , 24 , 26 , 28 , [30] , [31] , [32] , [33] , [34] , [37] , [38] , [39] , [40] , [41] , [42] , 44 , 45 , 50 , 52 , 54 , 55 ] journals between 1999 and 2020 ( Supplementary Information 3 ). Evidently, this is a new and expanding field, with more articles published in the last 5 years (n = 24) [ [2] , [3] , [4] , 14 , 17 , 19 , 22 , 23 , 25 , 26 , 28 , [32] , [33] , [34] , [35] , 39 , 41 , [45] , [46] , …”

“…In terms of surgical specialty ( Supplementary Information 2 , Table 1 ), the highest proportion of studies (in-vivo and ex-vivo models) were in general surgery (n = 14, 31.1%) [ 3 , 5 , 20 , 26 , 27 , 35 , 38 , [41] , [42] , [43] , 49 , 51 , 54 ] with the majority of these involving laparoscopic procedures (n = 11) [ 3 , 5 , 26 , 34 , 38 , [41] , [42] , [43] , 49 , 54 , 55 ]; followed by neurosurgery (n = 13, 28.89%) [ 1 , 2 , 4 , 14 , 22 , 23 , 25 , 28 , 33 , 37 , 44 , 52 ], ophthalmology (n = 5, 11.11%) [ [17] , [18] , [19] , 21 , 32 ], cardiothoracic (n = 3, 6.67%) [ 26 , 30 , 53 ], vascular surgery (n = 3, 6.67%) [ 29 , 40 , 50 ], obstetrics & gynaecology (n = 2, 4.4%) [ 39 , 45 ], orthopaedics (n = 2, 4.4%) [ 47 , 48 ], otorhinolaryngology (n = 2, 4.4%) [ 36 , 46 ] and urology (n = 1, 2.2%) [ 24 ]. Ten studies (22.2%) involved robotic surgery platforms [ 1 , 14 , [17] , [18] ,…”

“…Generally, across tasks and models, specialities requiring the smallest amount of mean forces were: ophthalmology (mean of average 0.04N) [ [17] , [18] , [19] , 21 , 32 ], vascular (mean of average 0.07N) [ 29 , 40 , 50 ], neurosurgery (mean of average 0.68N) [ 1 , 2 , 4 , 14 , 22 , 23 , 25 , 28 , 33 , 37 , 44 , 52 ] and cardiothoracic surgery (mean of average 1.47N) [ 26 , 30 , 53 ]. Higher mean of average forces, in ascending order, were seen in general surgery (mean of average 4.67N) [ 3 , 5 , 20 , 26 , 27 , 35 , 38 , [41] , [42] , [43] , 49 , 51 , 54 ], otorhinolaryngology (mean of average 8.49N) [ 36 , 46 ], obstetrics and gynaecology (mean of average 8.69N) [ 39 , 45 ], urology (mean of average 9.79N) [ 24 ] and orthopaedic surgery (mean of average 210N) [ 47 , 48 ].

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“…Across specialities and manoeuvres, nervous tissue (principally the brain & retina) required the least amount of force to manipulate (mean of average 0.4N, mean max 1.74N, n = 17) [ 1 , 2 , 4 , [17] , [19] , [21] , [22] , [23] , 25 , 28 , 32 , 33 , 37 , 44 , 52 ] with retinal forces always below 0.01N ( Table 1 ) [ [17] , [18] , [19] , 21 , 32 ]. Mean forces applied on epithelial tissues were higher (mean of average 3.8N, mean max 9.7N, n = 18) [ 3 , 14 , 20 , 24 , 26 , 27 , 29 , 35 , 38 , [40] , [41] , [42] , [43] , 45 , 50 , 51 , 54 ], followed by muscle (mean of average 4.1N, mean max 6.7N, n = 3) [ 5 , 49 , 51 ], and connective tissue including bone (mean of average 45.8N, mean max 347.9N, n = 10) [ 20 , 26 , 30 , 31 , 36 , 39 , [46] , [47] , [48] , 53 ]. Mean forces per surgical manoeuvre are reported in Table 1 with drilling recording the highest forces (mean of average 14.1N, mean max 25.9N, n = 2) [ 46 , 48 ], whilst sharp dissection recorded the lowest (mean of average 0.03N, mean max not available, n = 1) [ 1 ].…”