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Simulation

Advanced Hysteroscopy

Module

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Learning Objectives

By the end of this lesson, you should be able to do the following:

  • Identify basic equipment needs to perform intrauterine resection
  • Describe the differences in distention media necessary for monopolar versus bipolar cautery
  • Explain when to discontinue a procedure based on fluid management issues

Performance of a Hysteroscopic Resection

  1. Properly assemble the hysteroscope with operating element
  2. Select the proper distention media for electrosurgical device (monopolar versus bipolar)
  3. Insert scope atraumatically
  4. When resecting use a draw back technique
    • Only activate the electrosurgical element when pulling back toward the lens
  5. Monitor fluid levels closely

Components of a Resectoscope

Components of a resectoscope used in advanced hysteroscopy. 

Basic Hysteroscopic Instrumentation

Telescopic Optical Characteristics

  • Field of view is summation of
    • Degree of field of view of distal lens
    • Angle of lens to central axis of telescope
    • The degrees noted for the lens represent the deflection of the view from 0º
  • Available fields of view
    • Centered lens = 0º
    • Offset (fore-oblique) expands field to 12º , 25º , or 30º
  • Angle of deflection is always opposite the light post

Telescopic optical instrument used in advanced hysteroscopy. 

Hysteroscopic Sheath Continuous Flow

  • Bipartite design: Inner and outer sheaths
  • Independent inflow and outflow channels for distension media
    • Inflow through inner sheath (always closest to eye piece)
    • Outflow through outer sheath
  • Continuous flushing and rinsing of the uterine cavity
    • Maintain a clear field of vision
  • Equipped with 3mm operating channel
    • Design allows instrument to be accurately placed anywhere within the uterine cavity

Hysteroscopic sheath used in advanced hysteroscopy. 

Methods of Improving Visualization

  • Over-dilation of cervix, allowing outflow of media, blood, and debris
  • Use directed aspiration with a disposable outflow catheter
  • Use a continuous flow sheath

IMAGE

Note that inflow is always the channel closets to the eyepiece and outflow is the channel furthest from the eyepiece.

The operative field can be clarified by over dilating the cervix to promote overflow, using directed aspiration with a disposable outflow catheter, or employing a continuous flow sheath.

Monopolar Resectoscopic Surgery

Use non-electrolyte, non-conductive solutions such as:

  • 3% sorbitol
  • 1.5% glycine
  • 5% mannitol
  • Sterile water

Monopolar Electrosurgery

  • Cuts and desiccates tissue
  • High current density at active electrode
  • Deep necrosis of tissue Broad thermal margins
  • Patient part of current pathway
  • Need for electrolyte-free fluid, otherwise the current disperses in saline

Use a non-electrolyte, low viscosity fluid

Mannitol 5%

  • Reduces risk of, but does eliminate the risk of, fluid overload and symptomatic hyponatremia
  • Near iso-osmolal at 274 mOsm/L
  • Essentially inert (6 - 10% metabolized)
  • Half-life 15 min, acts as osmotic diuretic
Monopolar electrosurgery used in advanced hysteroscopy. 

Bipolar System Mechanism of Vaporization

Current follows the path of least resistance. Electrical current is contained between the two electrodes producing heat.

Sodium vapor pocket

  • Contacts tissue
  • Instantaneous cellular rupture
  • Cutting is non-mechanical

Controlled thermal effect

Bipolar system vaporization used in advanced hysteroscopy. 

Bipolar Electrode Loop Electrode

Bipolar electrode loop electrode used in advanced hysteroscopy.

Continuous Flow Sheath

  • Operative hysteroscopes and resectoscopes
  • Inflow through inner channel: low resistance
  • Outflow through outer sheath: high resistance
  • Creates a clear visual field
  • Helps to maintains uterine distention

Continuous flow sheath used in advanced hysteroscopy.

Bipolar Electrosurgery or Non-Electro Surgery

  • Low Viscosity Electrolyte-Containing Solution
  • 0.9% sodium chloride (normal saline) Iso-osmolal, at 280 mOsm/L
  • Metabolically inert
  • Morbidities (>2.5 liters)
    • Volume overload
    • Left heart failure
    • Pulmonary edema

Factors Affecting the Intravasation of Liquid Distention Media

Surgery that opens larger vascular channels

  • Resection of myoma
  • Endomyometrial resection (adenomyosis)
  • Lysis of intrauterine adhesions
  • Division of uterine septum

Partial perforation

  • Cervical/lower segment tear
  • False passageway

Longer procedures, increased intrauterine pressures, and decreased mean arterial pressure in the patient also lead to increased intravasation.

Submucosal Fibroids Preoperative Evaluation ESGE

Percent intramural extension

  • Type 0 None
  • Type I < 50%
  • Type II > 50%
Diagram of submucosal fibroids.
Image used with permission. Transcervical hysteroscopic resection of submucous fibroids for abnormal uterine bleeding: results regarding the degree of intramural extension. Wamsteker K, et al. Obstet Gynecol 1993;82:736-740.

Submucosal Fibroids Hysteroscopic Myomectomy

With Type 2 myomas there is an increased risk of:

  • Excessive fluid absorption
  • Electrolyte abnormalities with non-electrolyte media
  • Excessive bleeding
  • Incomplete resection
  • Need for additional procedure
  • Increased operative time

Hysteroscopic Myomectomy Type 2 Myomas

Hysteroscopic myomectomy type 2 myomas increased fluid intravasation and risk of repeat procedures.

Type Type 1 Type 2 Total
Number of Patients 73 97 108 278
Number of Procedures 73 102 158 333
Complete Resection N = 73
100%
N = 95
98%
N = 103
95%
N = 271
97%
Repeat Procedures - 5% 40% 17%
Mean Fluid Intravasation cc 437 971 1642 1110

Source: Transcervical hysteroscopic resection of submucous fibroids for abnormal uterine bleeding: results regarding the degree of intramural extension. Wamsteker K, et al. Obstet Gynecol 1993;82:736-740.

Absorption of Non-Electrolyte Medium Mobidity and Mortality

  • Hypo-osmolality
  • Hyponatremia
  • Cerebral edema
  • Cardiac
  • Neuromuscular
  • Brain stem herniation
  • Death

Symptoms of Hyponatremia

Na Serum Level
Apprehension, disorientation, irritability, twitching, N & V, SOB 130–135
Pulmonary Edema, polyuria 123–130
Hypotension, bradycardia, cyanosis, mental changes 120–125
Encephalopathy, CHF, lethargy, confusion, seizures <120
Brainstem herniation, respiratory arrest, coma <115

Recommended Practices

Both anesthesiologist and surgeon should be aware of deficit on a frequent basis.

Automated fluid management highly desirable because it:

  • Removes the human factor
  • Allows for early warning of excess deficit
  • Provides the relative rate of intravasation

If mechanical monitoring is unavailable, a dedicated person should tally deficit as drum beat drill.

Automated Fluid Management

  • Allows for accurate accounting of fluid
    • Fluid usage
    • Fluid deficit
    • Fluid intravasation into tissue
  • Improved patient safety
  • Automated inflow rate in cc/min
  • Controlled outflow
  • Monitors intrauterine pressure
  • Essential for operative hysteroscopy

Fluid management system in advanced hysteroscopy.

Hysteroscopy Fluid Management Guidelines

  • Using electrolyte-free distention media
    • > 750 cc impending excessive intravasation
    • Plan completion of the surgery
  • > 1000 cc of electrolyte-free or >2500 cc saline
    • Bring surgery to an end
    • Check electrolytes
    • Consider Lasix 10 mg intravenously
  • Severe Hyponatremia
    • ICU consult/admission
    • CVP monitoring
    • Fluid restriction—diuretic

Source: Ad Hoc Committee on Hysteroscopic Fluid Management Guidelines of the AAGL 2000 JAAGL 7(2):167-168

Summary

  • For endometrial resection a rectoscope with active electrode is necessary
  • For monopolar electrodes a non-electrolyte solution is necessary
  • For bipolar a electrodes a electrolyte solution such as 0.9% NaCl is indicated
  • For non-electrolyte solutions extravasation can lead to hyponatremia
    • 1000-1500 cc deficit: stop procedure
  • For electrolyte solutions extravasation can lead to fluid overload
    • 2500 cc deficit: stop procedure

Author

  • Steven Swift, MD, Professor, Department of Obstetrics and Gynecology, Medical University of South Carolina

Developed in association with AAGL (Advancing Minimally Invasive Gynecology Worldwide).

Version 2.0, reaffirmed August 2016