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Monopolar Curved Scissors (da Vinci)

8 mm EndoWrist articulating curved scissors with integrated monopolar energy — the workhorse primary dissecting instrument for almost every robotic urology / urogyn / reconstructive case. Three dissection modes in a single instrument: cold sharp cutting, blunt spread, and monopolar electrosurgical cutting / coagulation. Typically deployed in the right (dominant) hand arm, paired with a bipolar grasper (Maryland or fenestrated) in the left and a ProGrasp on the fourth arm.[1][2][3]

Design​

  • 8 mm shaft, full EndoWrist (7 DoF) — same chassis as the needle drivers and bipolar instruments.[4]
  • Curved scissor blades with a sharp tip optimized for precise plane dissection.
  • Monopolar RF energy delivered via the active blade; requires a patient return electrode (grounding pad).[5]
  • Console foot pedals for separate cut (low-voltage continuous waveform, clean cut, minimal lateral thermal spread) and coag (high-voltage intermittent waveform, desiccation / hemostasis).
  • ~ 10-use disposable life.

Three Dissection Modes — One Instrument​

ModeActivationBest for
Cold sharpBlade closure, no pedalPlane dissection near NVB / nerve — no thermal spread
Blunt spreadClosed-tip enter → openAreolar plane development
Electrosurgical cutCut pedal — low V, continuousClean cutting through tissue with minimal thermal spread[5]
Electrosurgical coagCoag pedal — high V, intermittentDesiccation / hemostasis (relatively weak — no tissue compression)

The cut-vs-coag distinction is operationally important: cut mode is significantly safer than coag mode for stray-energy and thermal-spread reasons (below).

Reconstructive-Urology and Urogyn Uses​

Robotic radical prostatectomy — primary dissector​

  • All phases: peritoneal entry, space-of-Retzius development, bladder-neck transection, seminal-vesicle and prostatic-pedicle dissection, apical dissection.
  • Nerve-sparing NVB release — many surgeons advocate avoiding monopolar energy entirely near the NVB, using only cold sharp + blunt spread to minimize thermal neuropraxia. Modified clipless antegrade nerve-preservation specifically excludes monopolar cautery; occasional bipolar only.[6][7]
  • Cost-conscious three-instrument RARP — monopolar scissors is one of only three instruments needed (with Large Needle Driver and ProGrasp) for a complete RARP, reducing disposable cost up to 40% (Ramirez 2016).[3]

Robotic urogyn and reconstructive urology​

  • Robotic sacrocolpopexy — peritoneal incision, sigmoid mobilization, paravaginal-tunnel development, promontory exposure. Cold sharp / cut-mode preferred for plane work; avoid coag mode near the right ureter and presacral autonomic nerves.
  • Robotic ureteral reimplantation / Boari flap / psoas hitch / ureteroureterostomy — distal-ureteral mobilization (cold sharp near the ureter, never coag against the ureteral wall); bladder-flap raising.
  • Robotic transvaginal-mesh excision — sharp plane dissection between mesh and bladder / bowel / vagina; cold sharp preferred to limit thermal spread to repair lines.
  • Robotic VVF / ureterovaginal-fistula repair — fistula-tract delineation and excision.
  • Robotic radical cystectomy with diversion-component reconstruction — Kurpad 2015 setup places monopolar scissors in the right arm, fenestrated bipolar in the left, ProGrasp in the third.[8]

Cross-specialty signals supporting the workhorse role​

  • Cui 2019 robotic anterior rectal-cancer resection — monopolar scissors vs harmonic scalpel: significantly shorter OR time 81.5 vs 95.6 min (p < 0.05).[1]
  • Okabe 2019 robotic gastrectomy (n = 115) — monopolar scissors safe and feasible, 1.7% intraoperative complications, no open conversion; sharp dissection may reduce pancreatic injury during suprapancreatic LN dissection vs ultrasonic devices.[9]
  • Robotic esophagectomy (Hirahara 2022) — sharp + articulating tip enables fast mediastinal dissection and LN harvest; weak hemostasis must be paired with bipolar.[2]
  • TORS on SP — monopolar cautery scissor is the alternative to the spatula-type MCI when scissor action is preferred.[10]

Thermal Spread — The Operational Number That Matters​

Hefermehl 2014 lateral-temperature-spread data (mean critical spread to 45 °C nerve-damage threshold at 60 W):[11]

Instrument1 s activation2 s activation
Monopolar scissors3.5 mm> 20 mm
Bipolar (Maryland)2.2 mm3.6 mm
Ultrasonic2.9 mm—

Implications for nerve-sparing work: monopolar at 2 s exceeds 20 mm of thermal spread — well beyond any safe NVB / obturator / pudendal margin. Use brief activations only, and place a Maryland clamp as a heat sink between the scissor tip and the nerve when energy must be used near it (Hefermehl 2014).[11]

Residual heat — wait before tissue contact​

Brinkmann 2022: after activation the monopolar shaft can exceed 120 °C over the distal 10 mm and remain > 50 °C for at least 15 s. Avoid tissue contact for 15 s after activation to prevent inadvertent thermal injury.[12]

Stray Energy Transfer — Unique to Monopolar​

Stray energy transfer from the monopolar scissor to adjacent non-energized instruments (assistant graspers, camera tip) is a robotic-specific safety issue (Overbey 2021):[13]

Open-air activation (30 W coag)Temp rise on assistant grasper
Standard setup+18.3 °C
Lower power 15 W+2.6 °C
Cut mode (low-voltage) instead of coag+3.1 °C
Avoid open-air activation (desiccate tissue, don't fire in air)+0.15 °C — virtually eliminated
Camera tip+9.0 °C

Generator choice matters too:

  • Constant-voltage regulating generator (cVRG, eg ERBE VIO 300 dV) — +4.4 °C during coag mode.
  • Constant-power regulating generator (cPRG, eg ForceTriad) — +41.1 °C during coag mode.[14]

Single-incision robotic surgery (SIRS) carries higher stray-energy risk than multiport (11.6 vs 8.4 °C, p = 0.013) because instruments are bunched in one cannula; cVRG generators mitigate.[15]

Ceramic-coated electrodes​

Newer ceramic-coated monopolar electrodes reduce lateral thermal damage by 86% at 35 W / 65% at 50 W vs standard electrodes; robotic cutting with ceramic also reduces midline thermal damage 47% and lateral 33%.[16]

Monopolar Scissors vs Other da Vinci Energy Instruments​

FeatureMonopolar Curved ScissorsMaryland bipolarVessel Sealer (SynchroSeal)Harmonic Scalpel
EnergyMonopolar RF (~ 500 kHz)Bipolar RFBipolar RFUltrasonic (55 kHz)
ArticulationFull EndoWristFull EndoWristFull EndoWristNo articulation
Dissection modesCold sharp + blunt + electrosurgicalGrasping + bipolar coagSealing + cuttingCutting + coagulation
Hemostatic abilityWeak (no tissue compression)ModerateStrong (vessels ≤ 7 mm)Moderate (vessels ≤ 5 mm)
Thermal spread (1 s / 60 W)3.5 mm2.2 mm2.8–3.9 mm2.9 mm
Thermal spread (2 s / 60 W)> 20 mm3.6 mm——
Stray-energy riskYes (requires return pad)No (bipolar)No (bipolar)No (mechanical)
Best forPrimary dissectionCoagulation + heat sinkVessel sealing / transectionRapid transection
Disposable costLowerLowerHigherHigher

Practical Safety Pearls​

  • Cut mode > coag mode for safety — lower voltage means lower thermal spread and lower stray-energy.[13][14]
  • Avoid open-air activation — desiccate tissue, don't fire in air.[13]
  • Brief activations only — 1 s gives 3.5 mm spread; 2 s gives > 20 mm.[11]
  • Wait 15 s after activation before contacting other tissue with the instrument.[12]
  • Pair with a bipolar contralaterally for hemostasis and for heat-sink protection of nearby nerves.[11][2]
  • Cold sharp / blunt for NVB and ureteral dissection — clipless antegrade and Retzius-sparing techniques specifically avoid monopolar energy near the NVB.[6][7]
  • Choose a cVRG-class generator (eg ERBE VIO 300 dV) over cPRG generators for an order-of-magnitude stray-energy reduction in coag mode.[14]
  • Lowest effective power setting — 15 W vs 30 W reduced stray energy from 18.3 → 2.6 °C in Overbey 2021.[13]

Limitations​

  • Weak hemostasis — no tissue compression; pair with bipolar.
  • Thermal spread balloons at 2 s of activation — keep activations brief.
  • Stray energy is a monopolar-only concern; mitigated but not eliminated by generator / power / mode choices.
  • No tactile feedback — visual cues only for tissue tension during scissor closure.

See also: Needle Drivers (da Vinci), Maryland Bipolar, Fenestrated Bipolar, Force Bipolar, ProGrasp, Cadiere, Tip-Up Fenestrated, Electrosurgical Pencil, Bovie Tips.

References​

1. Cui R, Yu MH, Chen JJ, et al. "Monopolar electrosurgical scissors versus harmonic scalpel in robotic anterior resection of rectal cancer: a retrospective cohort study." J Laparoendosc Adv Surg Tech A. 2019;29(7):880–5. doi:10.1089/lap.2018.0740

2. Hirahara N, Matsubara T, Hayashi H, Tajima Y. "Features and applications of energy devices for prone robot-assisted minimally invasive esophagectomy: a narrative review." J Thorac Dis. 2022;14(9):3606–12. doi:10.21037/jtd-22-559

3. Ramirez D, Ganesan V, Nelson RJ, Haber GP. "Reducing costs for robotic radical prostatectomy: three-instrument technique." Urology. 2016;95:213–5. doi:10.1016/j.urology.2016.03.067

4. Melzer A, Cochran S, Prentice P, et al. "The importance of physics to progress in medical treatment." Lancet. 2012;379(9825):1534–43. doi:10.1016/S0140-6736(12)60428-0

5. Vilos GA, Rajakumar C. "Electrosurgical generators and monopolar and bipolar electrosurgery." J Minim Invasive Gynecol. 2013;20(3):279–87. doi:10.1016/j.jmig.2013.02.013

6. Chien GW, Mikhail AA, Orvieto MA, et al. "Modified clipless antegrade nerve preservation in robotic-assisted laparoscopic radical prostatectomy with validated sexual function evaluation." Urology. 2005;66(2):419–23. doi:10.1016/j.urology.2005.03.015

7. Asimakopoulos AD, Miano R, Galfano A, et al. "Retzius-sparing robot-assisted laparoscopic radical prostatectomy: critical appraisal of the anatomic landmarks for a complete intrafascial approach." Clin Anat. 2015;28(7):896–902. doi:10.1002/ca.22576

8. Kurpad R, Woods M. "Robot-assisted radical cystectomy." J Surg Oncol. 2015;112(7):728–35. doi:10.1002/jso.24009

9. Okabe H, Obama K, Tsunoda S, et al. "Feasibility of robotic radical gastrectomy using a monopolar device for gastric cancer." Surg Today. 2019;49(10):820–7. doi:10.1007/s00595-019-01802-z

10. Oberhelman N, Bruening J, Jackson RS, et al. "Comparison of da Vinci Single Port vs Si systems for transoral robotic-assisted surgery: a review with technical insights." JAMA Otolaryngol Head Neck Surg. 2024;150(2):165–71. doi:10.1001/jamaoto.2023.3994

11. Hefermehl LJ, Largo RA, Hermanns T, et al. "Lateral temperature spread of monopolar, bipolar and ultrasonic instruments for robot-assisted laparoscopic surgery." BJU Int. 2014;114(2):245–52. doi:10.1111/bju.12498

12. Brinkmann F, Hüttner R, Mehner PJ, et al. "Temperature profile and residual heat of monopolar laparoscopic and endoscopic dissection instruments." Surg Endosc. 2022;36(6):4507–17. doi:10.1007/s00464-021-08804-4

13. Overbey DM, Carmichael H, Wikiel KJ, et al. "Monopolar stray energy in robotic surgery." Surg Endosc. 2021;35(5):2084–90. doi:10.1007/s00464-020-07605-5

14. Wikiel KJ, Powlan FJ, Jones TS, Robinson TN, Jones EL. "Robotic stray energy with constant-voltage versus constant-power regulating electrosurgical generators." Surg Endosc. 2023;37(1):580–6. doi:10.1007/s00464-022-09316-5

15. Wikiel KJ, Overbey DM, Carmichael H, et al. "Stray energy transfer in single-incision robotic surgery." Surg Endosc. 2021;35(6):2981–5. doi:10.1007/s00464-020-07742-x

16. Ewertowska E, Casey VJ, Whiting R, et al. "Histological assessment of thermal damage in porcine muscle induced by monopolar electrosurgical cutting devices during manual and robotic testing." Int J Hyperthermia. 2024;41(1):2439549. doi:10.1080/02656736.2024.2439549